WO2010068578A1

WO2010068578A1 - Zero discharge produced water treatment system with minerals recovery, agricultural production and aquaculture

Info

Publication number: WO2010068578A1
Application number: PCT/US2009/066934
Authority: WO
Inventors: Paul Steven Wallace
Original assignee: Katana Energy Llc
Priority date: 2008-12-09
Filing date: 2009-12-07
Publication date: 2010-06-17

Abstract

A produced water treatment process includes a produced water treatment facility fluidly coupled to at least one minerals recovery system. The facility produces a recovered oil stream, an agricultural water stream, and at least one water treatment tailings stream from an inlet feed stream. The system produces a mineral compound, at least one potable water stream, and at least one minerals recovery tailings stream from a stream supplied by the water treatment tailings stream. At least one of the recovery tailings stream is recycled into a brine shrimp pond that produces brine shrimp. The pond is fluidly coupled between an RO unit located within the facility and one of the minerals recovery facility. The mineral compound includes gypsum, calcium chloride, magnesium chloride, sodium chloride, fertilizer, boric acid, potassium chloride, sodium bromide, and silicon dioxide which can be sold to increase revenue. The process can be connected to a gasification unit.

Description

ZERO DISCHARGE PRODUCED WATER TREATMENT SYSTEM WITH MINERALS RECOVERY, AGRICULTURAL PRODUCTION AND

AQUΛCULTURE

CROSS REFERENCE TO RELATED APPLICATIONS

[000 ! ] The present application claims priority from U.S. Provisional Patent

Application No. 61/120,920. entitled "Zero Discharge Produced Water Treatment System With Minerals Recovery, Agricultural Production And Aquaculture" and filed on December 9, 2008.

TECHNICAL FIELD

10002] This invention relates generally to methods and systems for treating brackish oil production wastewater, and, more particularly, to methods and systems for treating brackish oil production wastewater and recovering at least one of minerals, potable water, oil, and/or agricultural water from the brackish oil production wastewater.

BACKGROUND

[0003] A byproduct of crude oil production is contaminated water referred to as produced water. This water is typically brackish and is contaminated with hydrocarbons, heavy metals, selenium, boron, and fine solids. Typically, the produced water has about 5,000 to about 10,000 parts per million ('"ppm") total dissolved solids ("TDS").

[0004] Typically, this produced water is re-injected back into the underground oil reservoir to maintain pressure. However, as the oil is depleted, increasing amounts of water are produced due to the increasing water to oil ratio within the reservoir. For some formations this ratio can be greater than 6: 1 water to oil, and not all of the produced water can be re-injected without adversely impacting the reservoir and oil production. [0005] Currently, many oil producers are considering carbon dioxide ("CO₂") injection instead of water injection to recover oil and sequester CO₂. However, this method further reduces the amount of produced water that can be re-injected into the reservoir, thereby increasing the excess produced water.

[0006] Various treatment options have been considered for this excess produced water. However, treatment costs are high due to the large volume of produced water. Treatment produces large volumes of hydrocarbons and metals rich sludge that is a toxic waste. Minerals recovery using a proprietary minerals recovery process (SAL-PROC technology from Geo-Processers Ltd) has been considered; however, this process is not suited to remove oil, metals, or the large amount of suspended solids in the produced water.

[0007] Biorcmediation schemes also have been considered to treat the produced water. However, these schemes produce bioaccumulation of metals, selenium, and boron. Additionally, bioremediation is subject to local climatic conditions which can cause significant evaporation, thereby concentrating the dissolved contaminants in the runoff water.

[0008] Evaporation ponds also have been considered to treat the produced water. However, these ponds would require a large surface area due to the low salt concentration in the produced water. Additionally, evaporation ponds using produced water generate a potentially toxic waste salt residue that creates a long term disposal problem since it is extremely leachable. Evaporation ponds producing salt and brine shrimp are currently in commercial operation. However, these ponds typically use only a small portion of the available area, approximately twenty-five percent, for brine shrimp production. These ponds are designed as once through seawater based operations that recover sodium chloride and reject a mixed tailings brine stream. The brine shrimp can be introduced into the ponds only after the salt concentration has been increased from 3.5 weight percent to eight weight percent. [0009] Currently reinjection into deep saline aquifers is being used to dispose of the produced water. However, this process is energy intensive and has the potential to cause underground aquifer contamination. Additionally, reinjection does allow utilization of the water resource. [0010] In view of the foregoing discussion, need is apparent in the art for providing improved treatment of produced water. Additionally, there exists the need for recovering one or more of the minerals, potable water, oil, and/or agricultural water during the treatment of produced water. Moreover, there exists a need for utilizing any by-products formed during the treatment of produced water. A technology addressing one or more such needs, or some other related shortcoming in the field, would benefit produced water treatment processes. This technology is included within the current embodiments of the invention.

SUMMARY fOO I l ] According to one embodiment, a produced water treatment process includes a produced water treatment facility and at least one minerals recovery system fluidly coupled to the produced water treatment facility. An inlet produced water feed stream enters the produced water treatment facility and produces a recovered oil stream, an agricultural water stream, and at least one produced water treatment tailings stream. A stream supplied by the produced water treatment tailings stream enters the minerals recovery system and produces at least one mineral compound, at least one potable water stream, and at least one minerals recovery tailings stream. [00121 According to another exemplary embodiment, a method for operating a produced water treatment process includes providing a produced water treatment facility and fluidly coupling at least one minerals recover)' system to the produced water treatment facility. An inlet produced water feed stream enters the produced water treatment facility and produces a recovered oil stream, an agricultural water stream, and at least one produced water treatment tailings stream. A stream supplied by the produced water treatment tailings stream enters the minerals recovery system and produces at least one mineral compound, at least one potable water stream, and at least one minerals recovery tailings stream.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The foregoing and other features and aspects of the invention may be best understood with reference to the following description of certain exemplary embodiments of the invention, when read in conjunction with the accompanying drawings, wherein:

[0014] Figure 1 shows a simplified flowchart of a produced water treatment process in accordance with an exemplary embodiment;

[0015] Figures 2A and 2B show a detailed flowchart of the produced water treatment process in accordance with an exemplary embodiment;

[0016] Figure 3 shows a predicted revenue bar chart for the produced water treatment process of Figures 2A and 2B in accordance with an exemplary embodiment;

[0017| Figure 4Λ shows a Gulf Cooperation Council ("GCC") (bod pricing bar chart for two consecutive years in accordance with an exemplary embodiment:

[0018| Figure 4B shows an Arab country food import bar chart in accordance with an exemplary embodiment; and

[0019 J Figure 5 shows a vegetable crop salinity yield potential and compound tolerance chart in accordance with an exemplary embodiment.

[0020] The drawings illustrate only exemplary embodiments of the invention and are therefore not to be considered limiting of its scope, as the invention may admit to other equally effective embodiments.

BRIEF DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0021 ] The application is directed to methods and systems for treating brackish oil production wastewater, or produced water. Jn particular, the application is directed to methods and systems for treating produced water and recovering at least one of minerals, potable water, oil, and/or agricultural water. The invention may be better understood by reading the following description of non-limiting, exemplary embodiments with reference to the attached drawings, wherein like parts of each of the figures are identified by the same reference characters, and which are briefly described as follows. [0022] Figure 1 shows a simplified flowchart of a produced water treatment process 100 in accordance with an exemplary embodiment. Λs shown, the produced water treatment process 100 includes an oil and metals recovery unit 1 10, a UF membrane 120. a NF membrane 130, a first minerals recovery unit 140, a RO unit 150, a brine shrimp pond 160, a second minerals recovery unit 170, and an agricultural unit 180. The oil and metals recovery unit 1 10, the UF membrane 120, the NF membrane 130, and the RO unit 150 collectively form a produced water treatment facility. Referring to Figure 1 , a produced water feed stream 102 enters the oil and metals recovery unit I 10. According to one example, the flowrate of the produced water feed stream 102 is approximately 900,000 cubic meters per day (m³/d). According to this exemplary embodiment, the produced water feed stream 102 includes two parts per million (ppm) of Boron and 7.000 ppm total dissolved solids (TDS).

|0023] Within the oil and metals recovery unit 1 10, the produced water feed stream 102 is separated into a recovered oil stream 1 12, a metals and solids stream 1 14, and a oil and metals recovery produced water outlet stream 1 16. The recovered oil stream 1 12 is returned to the oil production process (not shown), which forms the produced water feed stream 102. In one exemplary embodiment, the metals and solids stream 1 14 flows to a gasifier (not shown), where it is used as a co-feed. Within the gasifier. the hydrocarbons within the metals and solids stream 1 14 are converted to syngas, while the metals within the metals and solids stream 1 14 are vitrified into a glassy slag and converted into a non-leachable construction grade aggregate. In an alternative exemplary embodiment, the metals and solids stream 1 14 flows to an incinerator (not shown) for destruction. The oil and metals recovery produced water outlet stream 1 16 exits the oil and metals recovery unit 1 10 and proceeds to the UF membrane 120. According to one exemplary embodiment, the oil and metals recovery produced water outlet stream 1 16 exits the oil and metals recovery unit 1 10 at a pH of about 8.5.

[0024] The UF membrane 120 removes essentially all the remaining suspended solids, bacteria, viruses, and microbes from the oil and metals recovery produced water outlet stream 1 16. Within the UF membrane 120, the oil and metals recover)' produced water outlet stream 1 16 is separated into a UF permeate stream 124 and a UF non-permeate stream 122. The UF permeate stream 124, which has had essentially all the suspended solids, bacteria, viruses, and microbes removed, exits the UF membrane 120 and flows to the NF membrane 130. The UF non-permeate stream 122. which contains essentially all the suspended solids, bacteria, viruses, and microbes, exits the UF membrane 120 and is recycled back to the oil and metals recovery unit 1 10.

|0025] The NF membrane 130 removes most of the selenium, calcium, magnesium, sulfate, and any remaining heavy metals from the UF permeate stream 124. The NF membrane 130 operates to provide about a one hundred pounds per square inch (psi) differential pressure between the inlet stream and the outlet streams. Within the NF membrane 130, the UF permeate stream 124 is separated into a NF permeate stream 134 and a NF non-permeate stream 132. The NF permeate stream 134, which has had essentially most of the selenium, calcium, magnesium, sulfate, and any remaining heavy metals removed, exits the NF membrane 130 and flows to the RO unit 150. The NF non-permeate stream 132, which contains essentially most of the selenium, calcium, magnesium, sulfate, and any remaining heavy metals, exits the NF membrane 130 and flows to the first minerals recovery unit 140. [0026J Within the first minerals recovery unit 140, the NF non-permeate stream 132 is separated into a metals stream 142, a first potable water outlet stream 144, and a first minerals stream 146. The metals stream 142 includes iron, selenium, and other metals. According to one exemplary embodiment, the metals stream 142 exits the first minerals recovery unit 140 and (lows to the gasifier (not shown), where it is used as iron rich flux. In an alternative exemplary embodiment, the metals stream 142 flows to the incinerator (not shown) for destruction. The first potable water outlet stream 144 exits the first minerals recovery unit 140 and is used as potable water. According to the exemplary embodiment, the first potable water outlet stream 144 has a flowratc of approximately 50,000 m³/d. The first minerals stream 146, which includes gypsum, calcium chloride, magnesium chloride, and sodium chloride, exits the first minerals recovery unit 140 and is sold to market. In another exemplary embodiment, the first minerals stream 146 can be further processed or used in another industrial process without departing from the scope and spirit of the exemplary embodiment. In some exemplary embodiments, a portion of the first minerals stream 146, such as gypsum, is recycled back into the produced water treatment process 100.

[0027] Within the RO unit 150, the NF permeate stream 134 is separated into a RO permeate stream 154 and a RO non-permeate stream 152. The RO unit 150 operates with a low pressure drop, which is approximately 400 psi differential pressure. The RO permeate stream 154, which has had essentially all of the salt and much of the boron removed, exits the RO unit 150 and flows to the agricultural unit 180. According to this exemplary embodiment, about ninety-nine percent of the salt is rejected and about seventy percent of the boron is rejected within the RO unit 150. The RO permeate stream 154 is a high purity agricultural water stream that is used for irrigation of food products, such as vegetables. In this exemplary embodiment, the RO permeate stream 154 has a flowrate of approximately 650,000 m^"7d, has about one hundred ppm TDS, and is at about 8.5 pH. The RO non-permeate stream 152, which contains essentially all the salt and much of the boron, exits the RO unit 150 and flows to the brine shrimp pond 160. In this exemplar)' embodiment, the RO non- permeate stream 152 has a flowrate of approximately 200,000 m³/d. has about one 20,000 ppm TDS. and is at about 8.5 pH.

[0028] Within the brine shrimp pond 160, approximately ninety percent of the

RO non-permeate stream 152 is allowed to evaporate. Approximately ten percent of the RO non-permeate stream 152 exits the brine shrimp pond 160 in a brine shrimp pond sludge stream 162, which then flows to a second minerals recovery unit 170. Thus, according to this exemplary embodiment about 180.000 m³/d of RO non- permeate stream 152 is evaporated within the brine shrimp pond 160. Additionally, the brine shrimp pond sludge stream 162 has a flowrate of approximately 20,000 m7d. The brine shrimp pond 160 operates at a pH of about 8-8.5 and has approximately ten percent to about twenty percent TDS. The brine shrimp pond 160 is maintained at appropriate conditions for producing highly valuable brine shrimp, which is sold to market.

[0029] Within the second minerals recovery unit 170, the brine shrimp pond sludge stream 162 is separated into a second potable water outlet stream 174 and a second minerals stream 172. The second potable water outlet stream 174 exits the second minerals recovery unit 170 and is used as potable water. According to the exemplary embodiment, the second potable water outlet stream 174 has a flowratc of approximately 20,000 m³/d. The second minerals stream 172, which includes fertilizer, sodium chloride, boric acid, potassium chloride, sodium bromide, sodium chloride, and silicon dioxide, exits the second minerals recovery unit 170 and is sold to market. In another exemplary embodiment, the second minerals stream 172 can be further processed or used in another industrial process without departing from the scope and spirit of the exemplary embodiment. In some exemplary embodiments, a portion of the second minerals stream 172 is recycled back into the produced water treatment process 100.

[0030J As shown in Figure 1 , for 900.000 m³/d of produced feed water feed stream 102, 650,000 m³/d of agricultural water 154 and 70,000 m³/d of potable water 144 and 174 are produced. Thus, the process described in Figure 1 is about 80% efficient in producing agricultural water and potable water from produced water. [003 IJ Although exemplary flowrates, pl ls, concentrations, and efficiencies have been provided with respect to the process described in Figure 1 , alternative flowrates, pHs, concentrations, and/or efficiencies can be used without departing from the scope and spirit of the exemplary embodiment. Additionally, although a second minerals recovery unit 170 has been utilized within the process described in Figure I , the second minerals recovery unit 170 can be integrated with the first minerals recovery unit 140 without departing from the scope and spirit of the exemplary embodiment. Furthermore, although certain equipments and streams have been described for the process shown in Figure I , greater or fewer equipment can be used and/or the stream destinations may be altered, so long as the goals of each equipment has been maintained within the process, without departing from the scope and spirit of the exemplary embodiment.

[0032] Figures 2A and 2B show a detailed flowchart of the produced water treatment process 200 in accordance with an exemplary embodiment. Referring to Figures 2A and 2B, a produced water feed stream 201 enters an API separator unit 202 where approximately eighty percent of the oil and solids are removed from the produced water feed stream 201 . According to one example, the flowrate of the produced water feed stream 201 is approximately 900,000 m³/d. According to this exemplar)' embodiment, the produced water feed stream 201 includes about 500 ppm oil, about 7,000 ppm TDS, about 500 ppm total suspended solids (TSS), about 1 ,000 ppm metals, about two ppm boron, and about 0.2 ppm selenium. Λn ΛP1 separator recovered oil stream 203 exits the ΛPI separator unit 202 and is recycled to the oil production process (not shown), which forms the produced water feed stream 201. An API separator solids stream 204, which includes metals and solids, exits the API separator unit 202 and proceeds to a first rotary drum filter 215, which is described in further detail below. An API separator discharge water stream 205 exits the API separator unit 202 and flows to a dissolved air flotation (DAF) system 208. According to one exemplary embodiment, the API separator discharge water stream 205 includes about one hundred ppm TDS and about one hundred ppm oil. [0033J Within the DAF system 208, the API separator discharge water stream

205 is separated into a DAF recovered oil stream 209, a DAF solids stream 210, and a DAI-' discharge water stream 21 1. In the inlet section of the DAF system 208, an iron chloride stream 206, an anionic surfactant, and a sulfuric acid stream 207 arc mixed with the API separator discharge water stream 205, resulting in reducing the pH to about six and causing the solid particles to coalesce together. The acidic pH also causes the dissolved naphthenic acids to re-associate, thereby breaking the oil emulsions and causing the oil droplets to coalesce. The acidic mixture is then mixed with air (not shown) within a flotation section (not shown) in the DAF system 208. The air enables separation of the coalesced oil, water, and solids, thereby forming the DAF recovered oil stream 209, the DAF solids stream 210, and the DAF discharge water stream 21 1 . The DAF recovered oil stream 209 exits the DAF system 208 and is recycled to the oil production process (not shown), which forms the produced water feed stream 201 . In some exemplary embodiments, the DAF recovered oil stream 209 is combined with the ΛPI separator recovered oil stream 203 prior to reaching the oil production process. The DAF recovered oil stream 209 and the API separator recovered oil stream 203 combine to form about 3.000 barrels per day (bbl/d) being sent to the oil production process. The DAF solids stream 210, which includes metals and solids, exits the DAF system 208 and proceeds to the first rotary drum filter 215, which is described in further detail below. The DAF system discharge water stream 21 I exits the DAF system 208 and flows to an oil and metals removal primary settler 213. According to one exemplary embodiment, the DAF system discharge water stream 21 1 is at a pH of about six.

|0034] Within the oil and metals removal (OMR) primary settler 213, the

DAF system discharge water stream 21 1 is separated into an OMR primary settler solids stream 214 and an OMR primary settler discharge water stream 219. In the OMR primary settler 213. a pet coke coal stream 212, or activated carbon stream, is added to capture any remaining trace oil or naphthenic acid within the DAF system discharge water stream 21 1. Additionally, an iron chloride absorber bottoms stream 226 and a first rotary drum filter discharge stream 217, both of which are discussed in further detail below, also are recycled back into the OMR primary settler 213. The OMR primary settler solids stream 214, which includes metals and solids, exits the OMR primary settler 213 and proceeds to the first rotary drum filter 215. In some exemplary' embodiments, the OMR primary settler solids stream 214, the DAF solids stream 210, and the API separator solids stream 204 are combined prior to entering the first rotary drum filter 215. The OMR primary settler discharge water stream 219, which is acidic, exits the OMR primary settler 213 and flows to an OMR air stripper 221.

[0035] Within the first rotary drum filter 215, the OMR primary' settler solids stream 214, the DAF solids stream 210, and the API separator solids stream 204 are filtered to produce a first rotary drum metal and solids stream 218 and the first rotary drum filter discharge stream 217. A pet coke stream 216, or a coal pre-coat stream, is used to pre-coat the first rotary drum filter 215 to prevent the filter cloth from blinding from any tars or oils in the OMR primary settler solids stream 214, the DAF solids stream 210, and the API separator solids stream 204. A low TDS product water stream (not shown) is used to wash the filter cake that is produced within the first rotary drum filler 215, thereby minimizing the chloride content within the filter cake. According to one exemplar)' embodiment, the filter cake is then transported to a gasification unit for further processing via the first rotary drum metal and solids stream 218. In an alternative exemplary embodiment, the first rotary drum metal and solids stream 218 flows to an incinerator (not shown) for destruction. The first rotary drum metal and solids stream 218 includes coke, naphthenic acid, and phenol. As previously mentioned, the first rotary drum filter discharge stream 217 exits the first rotary drum filter 215 and is routed back to the OMR primary settler 213. [0036] Within the OMR air stripper 221 , the OMR primary settler discharge water stream 219 is stripped of carbon dioxide (COi), hydrogen sulfide (H₂S), and any trace light hydrocarbons to produce an OMR air stripper discharge water stream 223 and an OMR air stripper offgas stream 222. In the OMR air stripper 221 , an air stream 220 enters the OMR air stripper 221 at its bottom area and strips the OMR primary settler discharge water stream 219. The air stripper discharge water stream 223, which is acidic, exits the OMR air stripper 221 and flows to an OMR secondary settler 231. The OMR air stripper offgas stream 222 exits the OMR air stripper 221 and is routed to an iron chloride absorber 225.

[0037] Within the iron chloride absorber 225, hydrogen sulfide is removed as iron sulfide from the OMR air stripper offgas stream 222 to produce the iron chloride absorber bottoms stream 226 and an iron chloride absorber offgas stream 227. In the iron chloride absorber 225, an iron chloride (FeCb) stream 224 enters the iron chloride absorber 225 at its top area and absorbs hydrogen sulfide from the OMR air stripper offgas stream 222. The iron chloride absorber bottoms stream 226 exits the iron chloride absorber 225 and is routed to the OMR primary settler 213, as previously mentioned. The iron chloride absorber offgas stream 227 is routed to an activated canister 228, which is used to collect any trace organics within the iron chloride absorber offgas stream 227. From the activated canister, an activated canister discharge stream 229, which essentially includes pure air and carbon dioxide, is produced and routed to a brine shrimp pond 283, which is described in further detail below.

[0038J Within the OMR secondary settler 231 , the air stripper discharge water stream 223 is separated into an OMR secondary settler solids stream 232 and an OMR secondary' settler discharge water stream 236. In the OMR secondary settler 231, a lime stream 230 is added to the air stripper discharge water stream 223 to increase its pH to about 8.5 This precipitates most of the remaining metals and silica as a co- precipitatc with iron hydroxide. In some exemplary embodiments, a supplemental iron chloride stream (not shown) is added to the OMR secondary settler 231 depending upon metal content in the air stripper discharge water stream 223. Additionally, a UP non-permcate stream 238 and a second rotary drum filter discharge stream 235, both of which are discussed in further detail below, are recycled back into the OMR secondary settler 231. The OMR secondary' settler solids stream 232, which includes metals and solids, exits the OMR secondary settler 231 and proceeds to a second rotary drum filter 233. The OMR secondary settler discharge water stream 236, which is basic, exits the OMR secondary settler 231 and flows to a UF membrane 237.

[0039] Within the second rotary drum filter 233, the OMR secondary settler solids stream 232 is filtered to produce a second rotary drum metal and solids stream 234. which includes iron and metals, and the second rotary drum filter discharge stream 235. Λ low TDS product water stream (not shown) is used to wash the filter cake that is produced within the second rotary drum filter 233, thereby minimizing the chloride content within the filter cake. According to one exemplary embodiment, the filter cake is then transported to a gasification unit, where it is used as an iron rich flux, via the second rotary drum metal and solids stream 234. In an alternative exemplary embodiment, the second rotary drum metal and solids stream 234 flows to an incinerator (not shown) for destruction. The second rotary drum metal and solids stream 234 includes iron and metals. As previously mentioned, the second rotary drum filter discharge stream 235 exits the second rotary drum filter 233 and is routed back to the OMR secondary settler 231.

[0040] As previously mentioned, the OMR secondary settler discharge water stream 236 enters the UF membrane 237, where the UF membrane 237 removes essentially all the suspended solids, bacteria, viruses, and microbes from the OMR secondary settler discharge water stream 236. Within the UF membrane 237, the OMR secondary settler discharge water stream 236 is separated into a UF permeate stream 239 and the UF non-permeate stream 238. The UF permeate stream 239, which has had essentially all the suspended solids, bacteria, viruses, and microbes removed, exits the UF membrane 237 and flows to a NF membrane 240, where essentially all of the selenium, calcium, magnesium, sulfate, and any remaining heavy metals are removed. As previously mentioned, the UF non-permeate stream 238, which contains essentially all the suspended solids, bacteria, viruses, and microbes, exits the UF membrane 237 and recycles back to the OMR secondary settler 231. Additionally, an agricultural unit runoff stream 282, which is described in further detail below, also enters the UF membrane 237.

[0041] Within the NF membrane 240, UF permeate stream 239 is separated into a NF permeate stream 242 and a NF non-permcate stream 241. According to some of the exemplary embodiments, the NF membrane 240 operates at about one hundred psi differential pressure. The NF permeate stream 242, which has had essentially all of the selenium, calcium, magnesium, sulfate, and any remaining heavy metals removed, exits the NF membrane 240 at a pH of about 8.5, which is mildly basic, and flows to a RO unit 276. Prior to entering the RO unit 276, the NF permeate stream 242 is mixed with a first minerals recovery NF permeate stream 248, which is described in further detail below. The NF non-permcate stream 241 , which includes essentially all the selenium, calcium, magnesium, sulfate, and any remaining heavy metals, exits the NF membrane 240 and flows to a first minerals recovery UF membrane 243. where precipitated gypsum is removed from the NF non-permeate stream 241.

[00421 Within the first minerals recovery UF membrane 243_.. the NF non- permeate stream 241 is separated into a first minerals recovery UF permeate stream

245 and a first minerals recovery UF non-permeate stream 244. The first minerals recovery UF permeate stream 245 is routed to a first minerals recovery NF membrane

246 where most ofthc water from the NF non-permeate stream 241 is recovered. The first minerals recovery UF non-permeate stream 244 is routed to a first minerals recovery primary settler/filter 250. which is described in further detail below. [0043] Within the first minerals recovery NF membrane 246, the first minerals recovery UF permeate stream 245 is separated into the first minerals recovery NF permeate stream 248 and a first minerals recover)' NF non-permeate stream 247. As previously mentioned, the first minerals recovery NF permeate stream 248 is routed to the low pressure drop RO unit 276 via the NF permeate stream 242. However, in alternative exemplary embodiments_., the first minerals recovery NF permeate stream 248 can be routed to the RO unit 276 independently of the NF permeate stream 242. The first minerals recovery NF non-permeate stream 247 is routed to the first minerals recovery primary settler/filter 250, either independently of the first minerals recovery UF non-pcrmeate stream 244 or via the first minerals recovery UF non-permeate stream 244.

[0044] Within the low pressure drop RO unit 276, the NF permeate stream

242 and the first minerals recovery- NF permeate stream 248 are combined and separated into a RO permeate stream 279 and a RO non-permeate stream 277. According to one exemplary embodiment, the RO unit 276 operates at about a 8.5 pH and rejects about ninety-nine percent of the salt and about seventy percent of the boron. The RO unit 276 operates at about a four hundred psi differential pressure. The RO permeate stream 279 is a high purity agricultural water stream that is suitable for vegetable irrigation. According to one exemplary embodiment, the RO permeate stream 279 has a flowrate of about 650,000 mVd and includes agricultural water and about one hundred ppm TDS. The RO permeate stream 279 is routed to an agricultural unit 280 for irrigating food products, such as vegetables. The RO non- permeate stream 277 is routed to the brine shrimp pond 283, or evaporation pond, which is described in further detail below. According to one exemplar)' embodiment, the RO non-permeate stream 277 has a flowrate of about 200,000 m³/d and includes about 20,000 ppm TDS. Prior to the RO non-permeate stream 277 entering the brine shrimp pond 283, a magnesium chloride and calcium chloride stream 278 is added to the RO non-permeate stream 277 to increase magnesium content to the level required by the brine shrimp that is produced within the brine shrimp pond 283. However, in alternative exemplary embodiments, the magnesium chloride and calcium chloride stream 278 can be added directly to the brine shrimp pond 283 or indirectly through any other stream entering the brine shrimp pond 283.

[0045] Within the agricultural unit 280, the RO permeate stream 279 is used to produce food products, such as vegetables. A gypsum inlet stream 281 and a fertilizer stream 286 are added to the agricultural unit 280 for facilitating food production. The gypsum inlet stream 281 and the fertilizer stream 286 are produced within the produced water treatment process 200; however, in alternative exemplary embodiments, these streams 281 and 286 can be provided from elsewhere without departing from the scope and spirit of the exemplary embodiment. The agricultural unit 280 produces the food crop and the agricultural unit runoff stream 282, which, as previously mentioned, is recycled back to the UF membrane 237. [0046] Within the first minerals recovery primary settler/filter 250. a sulfuric acid stream 249 is added to the combined first minerals recovery UF non-permeate stream 244 and the first minerals recovery NF non-permcate stream 247 to adjust the pH to about six and to facilitate gypsum recovery. The sulfuric acid stream 249 can be added to either to the first minerals recovery UF non-permeate stream 244, the first minerals recovery NF non-permeate stream 247, or directly into the first minerals recovery primary settler/filter 250. Additionally, a second minerals recover)' NF non- permeate stream 294 also is added into the first minerals recovery primary settler/filter 250. The first minerals recovery UF non-permeate stream 244 and the first minerals recovery NF non-permeate stream 247 are separated into a gypsum product stream 251 and a first minerals recovery primary settler/filter overflow stream 252. Most of the gypsum product stream 25 1 is sold; however, a portion of the gypsum product stream 251 is used in conjunction with the RO permeate stream 279 within the agricultural unit 280 to decrease the sodium absorption ratio of the water, thereby preventing crop drainage problems. As previously mentioned, the portion of gypsum that is used in conjunction with the RO permeate stream 279 flows to the agricultural unit 280 via the gypsum inlet stream 281 . The first minerals recovery primary scttler/filtcr overflow stream 252 is routed to a first minerals recovery de- aerator 253. According to one of the exemplary embodiments, the flowratc of the first minerals recovery primary settler/filter overflow stream 252 is about 50,000 nτ7d. [0047| Within the first minerals recovery de-aerator 253, the first minerals recovery primary settler/filter overflow stream 252 is separated into a first minerals recover)' de-aerator off-gas stream 255 and a first minerals recovery de-aerator bottoms stream 254. Additionally, a first minerals recovery crystallizer recycle stream 258. which is described in further detail below, also enters the first minerals recovery de-aerator 253 to facilitate de-aeration of the first minerals recover)' primary settler/filter overflow stream 252. The first minerals recovery de-aerator off-gas stream 255 is high quality desalinated condensate that can be used as potable water. The first minerals recovery de-aerator bottoms stream 254 is routed to a first minerals recovery crystallizer 256.

(0048] The first minerals recover)' crystallizer 256. which can be a mechanical vapor recompression (MVR) crystallizer, vaporizes the first minerals recovery dc- aerator botioms stream 254 to produce a first potable water outlet stream 259, the first minerals recovery crystallizer recycle stream 258, a calcium and magnesium salt stream 257, and a first minerals recovery crystallizer bottoms water stream 260. Additionally, a first minerals recovery tertiary settler/filter overllow stream 275 also is recycled back to the first minerals recovery crystallizer 256, which is described in further detail below. The first potable water outlet stream 259 combines with the first minerals recovery de-aerator off-gas stream 255 and is used as potable water. According to one exemplary embodiment, the fiowrate of the combined first potable water outlet stream 259 and first minerals recovery de-aerator off-gas stream 255 is about 50,000 m³/d. In some exemplary embodiments, a iime stream 261 and a bleach stream 262 is added to the combined first potable water outlet stream 259 and first minerals recovery de-aerator off-gas stream 255. The lime stream 261 is added to remineralize and pH stabilize the streams 259 and 255 . The bleach stream 262 is added to disinfect and treat the combined first potable water outlet stream 259 and first minerals recovery de-aerator off-gas stream 255 so that they can be used as potable water. As previously mentioned, the first minerals recovery crystallizer recycle stream 258 is recycled back to the first minerals recovery de-aerator 253 for facilitating de-aeration of the first minerals recovery primary settler/filter overflow stream 252. The calcium and magnesium salt stream 257 is sold as a byproduct salt for magnesium and calcium chloride recover}' in an off-site minerals recovery plant (not shown). The calcium and magnesium salt stream 257 includes magnesium chloride, calcium chloride, and sodium chloride. The first minerals recovery crystallizer bottoms water stream 260 is routed to a first minerals recovery secondary settler/filter 268.

[0049] Within the first minerals recovery secondary settler/filter 268, the first minerals recovery crystallizer bottoms water stream 260 is separated into an iron selenium stream 269 and a first minerals recovery secondary settler/filter overflow stream 270. A ferrous chloride stream 266 and a lime stream 267 are added to the first minerals recovery secondary settler/filter 268 to adjust the pH to about nine. This reduces the selenate to selenium and co-precipitates it with iron. The iron selenium stream 269 is filtered, and the resulting iron and selenium filter cake is sent to the gasification unit for use as iron rich flux. The first minerals recovery secondary' settler/filter overflow stream 270 is routed to a first minerals recovery tertiary settler/ filter 273.

[00501 The ferrous chloride stream 266 is produced as a discharge from a mixer 263. Λ ferric chloride stream 264 and an iron stream 265 are mixed into the mixer 263. thereby forming the ferrous chloride stream 266. As previously mentioned, this ferrous chloride stream 266 is introduced into the first minerals recovery secondary settler/filter 268.

[0051 ] Within the first minerals recovery tertiary settler/filter 273, the first minerals recovery secondary settler/filter overflow stream 270 is separated into an iron and metals stream 274 and the first minerals recovery tertiary settler/filter overflow stream 275. The first minerals recovery tertiary settler/filter 273 includes a reactor portion (not shown) and a settler portion (not shown). The first minerals recovery secondary settler/filter overflow stream 270 is routed to the reactor portion where an air stream 271 is added to oxidize the ferrous iron within the first minerals recovery secondary settler/filter overflow stream 270 into ferric iron. The oxidized mixture is then sent to the settler portion where the oxidized mixture is mixed with a lime stream 272, thereby causing the oxidized iron and any remaining metals to co- precipitate out of the mixture and form the iron and metals stream 274. In one exemplary embodiment, the lime stream 272 is at a pH of about nine. The iron and metals stream 274 is filtered, and the resulting iron and metal filter cake is sent to the gasification unit for use as iron rich flux. The first minerals recovery tertiary settler/filter overflow stream 275 is recycled back to the first minerals recovery crystal lizcr 256. as previously mentioned.

[0052] Referring back to the brine shrimp pond 283, the brine shrimp pond is used to evaporate approximately ninety percent of the RO non-permeate stream 277. These large ponds 283 also are used to produce highly valuable brine shrimp. The brine shrimp thrive in high salinity, hot sunny conditions. According to some of the exemplary embodiments, the brine shrimp pond 283 operates at a pH between about 8-8.5 and includes about ten to twenty percent TDS. A small amount of nutrients are added to the pond to promote algae growth which feeds the shrimp. For example, an ammonia and phosphate stream 630 is added to the brine shrimp pond 283 to promote algae growth. In some exemplary embodiments, the ammonia and phosphate stream 630 includes at least one of ammonia, phosphates, and urea. In another example, the activated canister discharge stream 229, which has elevated levels of carbon dioxide content, also is added to the brine shrimp pond 283 to increase the oxygen and carbon dioxide levels within the brine shrimp pond 283 which results in increasing both the brine shrimp and the algae growth. As previously mentioned, the magnesium chloride and calcium chloride stream 278 also is added to the brine shrimp pond 283 to increase magnesium content within the brine shrimp pond 283 to the level required by the brine shrimp. Additionally, a second minerals recovery primary' UF permeate recycle stream 292. a second minerals recovery NF non-permeate recycle stream 295, a second minerals recovery secondary crystallizer recycle stream 627, a second minerals recovery secondary crystallizer overheads stream 628, a second minerals recover}' tertiary crystallizer recycle stream 623, and a second minerals recovery tertiary crystallizer overheads stream 624, which are all discussed in further detail below, are recycled back into the brine shrimp pond 283. One or more of the streams entering the brine shrimp pond 283 can enter directly into the brine shrimp pond 283 or can be combined with any other stream entering the brine shrimp pond 283 without departing from the scope and spirit of the exemplary embodiment. A brine shrimp pond bottoms sludge stream 284 is discharged from the brine shrimp pond 283 and is routed to a second minerals recovery settler/filter 285.

[OO53J Within the second minerals recovery settler/filter 285, the brine shrimp pond bottoms sludge stream 284 is settled and filtered to produce a second minerals recovery settler/filter overflow stream 287 and a filter cake (not shown), which is washed and dried before being removed in the fertilizer stream 286. The second minerals recovery settler/filter overflow stream 287 is routed to a second minerals recovery primary UF membrane 288 to remove any remaining suspended solids and most pathogens. In one exemplary embodiment, the second minerals recovery settler/filter overflow stream 287 has a flowrate of about 20,000 mVd. The fertilizer stream 286, as previously mentioned, is routed to the agricultural unit 280 for producing food products. Additionally, a second minerals recovery primary UF non- permeate stream 289 also is recycled back into the second minerals recover)' settler/filter 285. [0054] Within the second minerals recovery primary UF membrane 288, the second minerals recovery settler/filter overflow stream 287 is separated into a second minerals recovery primary UF permeate stream 290 and the second minerals recovery primary UF non-permeate stream 289. The second minerals recovery primary UF permeate stream 290 is routed to a second minerals recovery NF membrane 293 to purge the salt, thereby maintaining the brine shrimp pond 283 salinity below the brine shrimp limit of about 200,000 ppm TDS. However, a portion of the second minerals recovery primary UF permeate stream 290, as previously mentioned, is recycled back to the brine shrimp pond 283 via the second minerals recovery primary UF permeate recycle stream 292. The portion of the second minerals recovery primary UF permeate stream 290 that is routed to the second minerals recovery NF membrane 293 is combined with a sulfuric acid stream 291 to adjust the pH of the stream to about six. As previously mentioned, the second minerals recovery' primary UF non- permeate stream 289 is recycled back to the second minerals recover)' settler/filter 285. Additionally, an iron chloride absorber bottoms stream 604 is recycled back to the second minerals recovery primary UF membrane 288.

[0055] Within the second minerals recovery NF membrane 293, the second minerals recovery primary UF permeate stream 290 is separated into a second minerals recover)' NF permeate stream 296 and the second minerals recovery NF non- permeale stream 294. The second minerals recovery NF membrane 293 removes calcium, magnesium, sulfate, and selenate from the second minerals recovery primary UF permeate stream 290. The second minerals recovery NF permeate stream 296, which has essentially most of the calcium, magnesium, sulfate, and selenate removed, exits the second minerals recovery NF membrane 293 and is routed to a second minerals recovery de-aerator 297. The second minerals recovery NF non-pcrmcate stream 294 is> routed to the first minerals recovery primary settler/filter 250. as previously mentioned, and is used to purge brine from the brine shrimp pond 283. Additionally, a portion of the second minerals recovery NF non-permeate stream 294, as previously mentioned, is recycled back to the brine shrimp pond 283 via the second minerals recovery NF non-permeate recycle stream 295. The second minerals recovery NF non-permeate recycle stream 295 is used to maintain the minimum calcium, magnesium, and sulfate content within the brine shrimp pond 283. [0056] Within the second minerals recovery dc-aerator 297, the second minerals recovery NF permeate stream 296 is separated into a second minerals recovery de-aerator ofT-gas stream 299 and a second minerals recovery de-aerator bottoms stream 298. Additionally, a second minerals recovery primary crystallizer recycle stream 610, which is described in further detail below, also enters the second minerals recover)' de-aerator 297 to facilitate de-aeration of the second minerals recovery NF permeate stream 296. The second minerals recovery de-aerator off-gas stream 299 is high quality desalinated condensate that can be used as potable water, but is first sent through an off-gas cooler 600. The second minerals recovery de- aerator bottoms stream 298 is routed to a second minerals recovery primary crystallizer 608.

[0057] The off-gas cooler 600 cools the second minerals recovery de-aerator off-gas stream 299 and forms a off-gas cooler discharge stream 601 , which exits the off-gas cooler 600 and is routed to an iron chloride absorber 603. Within the iron chloride absorber 603, the off-gas cooler discharge stream 601 is separated into an iron chloride absorber off-gas stream 605 and the iron chloride absorber bottoms stream 604. The iron chloride absorber 603 uses an iron chloride stream 602 to remove any hydrogen sulfide from the off-gas cooler discharge stream 601 . The hydrogen sulfide is removed from the off-gas cooler discharge stream 601 as iron sulfide. As previously mentioned, the iron chloride absorber bottoms stream 604, which includes iron sulfide, is routed to second minerals recovery primary UF membrane 288. The iron chloride absorber off-gas stream 605 is routed to the activated carbon guard bed 606. A activated carbon guard bed discharge stream 607 exits the activated carbon guard bed 606 and combines with a second potable water outlet stream 61 1 , which is further described below.

[0058] The second minerals recovery primary crystallizer 608, which can be a mechanical vapor recompression (MVR) crystallizer, vaporizes the second minerals recovery dc-acrator bottoms stream 298 to produce a second potable water outlet stream 61 1 , the second minerals recovery primary crystallizer recycle stream 610, a sodium chloride salt stream 609. and a second minerals recovery primary crystallizer bottoms water stream 614. Additionally, a second minerals recover)' secondary UF non-pcrmeate stream 616 also is recycled back to the second minerals recovery primary crystallizer 608, which is described in further detail below. The second potable water outlet stream 61 1 combines with the activated carbon guard bed discharge stream 607 and is used as potable water. According to one exemplary embodiment, the flowrate of the combined second potable water outlet stream 61 1 and the activated carbon guard bed discharge stream 607 is about 20,000 m^'Vd. In some exemplary embodiments, a lime stream 612 and a bleach stream 613 is added to the combined second potable water outlet stream 61 1 and activated carbon guard bed discharge stream 607. The lime stream 612 is added to remineralize and pH stabilize the streams 61 1 and 607 . The bleach stream 613 is added to disinfect and treat the combined second potable water outlet stream 61 1 and activated carbon guard bed discharge stream 607 so that they can be used as potable water. As previously mentioned, the second minerals recovery primary crystallizer recycle stream 610 is recycled back to the second minerals recovery de-aerator 297 for facilitating de- aeration of the second minerals recovery NF permeate stream 296. The sodium chloride salt stream 609 includes high purity sodium chloride salt and is sold as a byproduct salt. The second minerals recovery primary crystallizer bottoms water stream 614 is routed to a second minerals recovery secondary UF membrane 61 5 to remove suspended salt crystals and recycle them back to the second minerals recovery primary crystallizer 608.

|0059] Within the second minerals recovery secondary UF membrane 615, the second minerals recovery primary crystallizer bottoms water stream 614 is separated into a second minerals recovery secondary UF permeate stream 617 and the second minerals recovery secondary UF non-permeate stream 616. The second minerals recovery secondary UF permeate stream 617, which has had the suspended salt crystals removed, is routed to a second minerals recovery RO unit 618. According to one of the exemplary embodiments, the second minerals recover)' secondary UF permeate stream 617 has a flowrate of about 400 m³/d. As will be discussed in further detail below, a portion of the second minerals recovery secondary crystalliκer overheads stream 628 and a portion of the second minerals recovery tertiary crystallizer overheads stream 624 is routed back to the second minerals recovery RO unit 618 via a second minerals recovery crystallizer overheads recycle stream 629. According to some exemplary embodiments, the second minerals recovery crystallizer overheads recycle stream 629 cither directly flows into the second minerals recovery RO unit 618 or flows into the second minerals recovery RO unit 618 via the second minerals recovery secondary UF permeate stream 617. As previously mentioned, the second minerals recovery secondary UF non-permeatc stream 616, which includes the suspended salt crystals, is recycled back to the second minerals recovery primary crystallizer 608.

[0060] Within the second minerals recovery RO unit 618, the second minerals recovery secondary UF permeate stream 617 and the second minerals recovery crystallizer overheads recycle stream 629 arc separated into a second minerals recovery RO permeate stream 620 and a second minerals recovery RO non-permeate stream 619. The second minerals recovery RO permeate stream 620 is routed to a second minerals recovery secondary crystallizer 625. The second minerals recovery RO non-permeate stream 619 is routed to a second minerals recovery tertiary crystallizer 621.

|0061] The second minerals recovery secondary crystallizer 625, which can be a mechanical vapor recompression (MVR) crystallizer, removes high purity boric acid from the second minerals recovery RO permeate stream 620. Within the second minerals recovery secondary crystallizer 625, the second minerals recovery RO permeate stream 620 is separated into the second minerals recovery secondary crystallizer recycle stream 627, the second minerals recovery secondary crystallizer overheads stream 628, and a boric acid stream 626. As previously mentioned, the second minerals recovery secondary crystallizer recycle stream 627, which includes sodium chloride, is recycled back to the brine shrimp pond 283. Also as previously mentioned, most of the second minerals recovery secondary crystallizer overheads stream 628 also is recycled back to the brine shrimp pond 283. However, some of the second minerals recovery secondary crystallizer overheads stream 628 is recycled back to the second minerals recovery RO unit 618, thereby reducing the salt concentration and facilitating boric acid separation within the second minerals recovery RO unit 618. The boric acid stream 626 includes high purity boric acid is sold for glass production.

[0062] The second minerals recovery tertiary crystallizer 621 , which can be a mechanical vapor recompression (MVR) crystallizer, removes bromide and potash rich salt from the second minerals recovery RO non-permeate stream 619. Within the second minerals recovery tertiary crystallizer 621 , the second minerals recover)' RO non-permeate stream 619 is separated into the second minerals recovery tertiary' crystallizer recycle stream 623, the second minerals recovery tertiary crystallizer overheads stream 624, and a bromide and potash salt stream 622. As previously mentioned, the second minerals recovery tertiary crystallizer recycle stream 623, which includes ammonia and phosphate nutrients, is recycled back to the brine shrimp pond 283. Also as previously mentioned, most of the second minerals recovery tertiary crystallizer overheads stream 624 also is recycled back to the brine shrimp pond 283. However, some of the second minerals recovery tertiary crystallizer overheads stream 624 is recycled back to the second minerals recovery RO unit 618. The bromide and potash salt stream 622 includes potassium chloride, sodium chloride, sodium bromide, and silicon dioxide, which is sold for potash and bromine recovery.

[0063] A portion of the brine and various crystallizer recycle streams are re- circulated back to the RO non-permeate stream 277, thereby elevating the salinity of the feed mixture going into the brine shrimp pond 283. The salinity is raised to a level above the minimum required for the brine shrimp, which is about 3.5 percent. The crystallizer operations are adjusted to maintain the ionic chemistry of the recycle streams plus inlet water within the optimal range for the brine shrimp. In some exemplary embodiments, sulfuric acid or lime is added to the inlet stream to adjust the inlet pl l to about seven to eight. In certain exemplary embodiments, sprays (not shown) using re-circulated brine are sprayed into the brine shrimp pond 283 to provide cooling during high ambient conditions.

[0064] As shown in Figure 2, for 900.000 m³/d of produced feed water feed stream 201, 650.000 mVd of agricultural water, or RO permeate stream 279, and 70,000 m³/d of potable water 61 1 and 259 are produced. Thus, the process described in Figure 2 is about 80% efficient in producing agricultural water and potable water from produced water.

[0065] Although exemplary flowratcs, pHs, concentrations, and efficiencies have been provided with respect to the process described in Figure 2, alternative flovvraies, pHs, concentrations, and/or efficiencies can be used without departing from the scope and spirit of the exemplary embodiment. Additionally, although certain equipments and streams have been described for the process shown in Figure 2, greater or fewer equipment can be used and/or the stream destinations may be altered, so long as the goals of each equipment has been maintained within the process, without departing from the scope and spirit of the exemplary embodiment. [0066] Figure 3 shows a predicted revenue bar chart 300 for the produced water treatment process 200 of Figures 2A and 2B in accordance with an exemplary embodiment. The revenue bar chart 300 has a revenue/expenditure source x-axis 301 and a revenue/expenditure amount y-axis 309. The revenue/expenditure source x-axis 301 is separated into three groups. One group is a reinjeclion expenditure 302. which is specific to a conventional process for disposing the produced water in an underground oil reservoir. The reinjection expenditure 302 includes expenditures associated with injecting the produced water into an underground oil reservoir. The second group is a cleanup revenue 304, which occurs when using the produced water treatment process 200 of Figures 2Λ and 2B. The cleanup revenue 304 includes revenue associated with potable water, minerals byproduct, vegetables, brine shrimp, and recovered oil. The minerals byproduct includes gypsum, sodium chloride (NaCl), magnesium chloride (Mg Ch), calcium chloride (CaCh), boric acid, potassium chloride (KCl)_.. sodium bromide (NaBr), and silicon dioxide (SiO:). The third group is a cleanup expenditure 306. which occurs when using the produced water treatment process 200 of Figures 2A and 2B. The cleanup expenditure 306 includes expenditures associated with capital recovery, power, plant operating and maintenance, and agricultural operating and maintenance. The revenue/expenditure amount y-axis 309 shows the revenue/expenditure amount for each group 302, 304, and 306 provided in the revenue/expenditure source x-axis 301 , in $MM/y. [0067] Expenditures 302 associated with reinjecting the produced water into an underground oil reservoir is illustrated by a reinjection expense bar 310. The reinjection expense bar 310 shows that conventional disposal processes expend about $75 MM/y for reinjecting the produced water. There are no capital expenditures or revenues associated with the conventional process for disposing the produced water. [0068] Cleanup revenue 304 associated with potable water is illustrated by a potable water revenue bar 320. The potable water revenue bar 320 shows that potable water, which is formed by treating the produced water, produces about S20 MM/y cleanup revenue. Cleanup revenue associated with minerals byproduct is illustrated by a minerals byproduct revenue bar 322. The minerals byproduct revenue bar 322 shows that minerals byproduct, which is formed by treating the produced water, produces about $80 MM/y cleanup revenue. Cleanup revenue associated with vegetables is illustrated by a vegetables revenue bar 324. The vegetables revenue bar 324 shows that vegetables, which is formed by treating the produced water and using water for irrigation, produces about S l , 145 MM/y cleanup revenue. Cleanup revenue associated with brine shrimp production is illustrated by a brine shrimp revenue bar 326. The brine shrimp revenue bar 326 shows that brine shrimp, which is produced by treating the produced water, produces about $180 MM/y cleanup revenue. Cleanup revenue associated with recovered oil is illustrated by a recovered oil revenue bar 328. The recovered oil revenue bar 328 shows that recovered oil, which is foπned by treating the produced water, produces about $90 MM/y cleanup revenue. Thus, approximately $1 ,515 MM/y revenue is generated when using the produced water treatment process 200 of Figures 2A and 2B.

[0069] Cleanup expenditure 306 associated with capital recovery is illustrated by a capital recovery expense bar 330. The capital recovery expense bar 330 shows that capital recovery expenses are about $ 100 MM/y cleanup expenditure. Cleanup expenditure associated with power is illustrated by a power expense bar 332. The power expense bar 332 shows that power expenses are about $40 MM/y cleanup expenditure. Cleanup expenditure associated with plant operating and maintenance is illustrated by a plant operating and maintenance expense bar 334. The plant operating and maintenance expense bar 334 shows that plant operating and maintenance expenses are about $65 MM/y cleanup expenditure. Cleanup expenditure associated with agricultural operating and maintenance is illustrated by an agricultural operating and maintenance expense bar 336. The agricultural operating and maintenance expense bar 336 shows that agricultural operating and maintenance expenses arc about S760 MM/y cleanup expenditure. Cleanup expenditure associated with chemical use is illustrated by a chemical expense bar 338. The chemical expense bar 338 shows that chemical expenses are about $25 MM/y cleanup expenditure. Thus, approximately $990 MM/y cleanup expenditures are needed when using the produced water treatment process 200 of Figures 2A and 2B. fOO7OJ As seen in Figure 3, the net revenue generated when using the produced water treatment process 200 of Figures 2A and 2B is seen by subtracting the cleanup expenditure 306 from the cleanup revenue 304. Thus, the net revenue is about S 1.5 1 5 MM/y - $990 MM/y extra, which is about $525 MM/y. The expenses generated by disposing the produced water according to conventional methods is about $75 MM/y. Thus, the net profits generated by using the produced water treatment process 200 of Figures 2A and 2B when compared to using conventional reinjection methods is about $525 MM/y - (-75MM/y) = 600 MM/y. [0071 ] Figure 4A shows a Gulf Cooperation Council ("'GCC") food pricing bar chart 400 for two consecutive years in accordance with an exemplary embodiment. The GCC food pricing bar chart 400 has a year x-axis 401 and a food price percentage increase y-axis 409. The year x-axis 401 depicts two consecutive years. One year is 2007 year 402, while the second year is 2008 year 404. The food price percentage increase y-axis 409 shows the percentage that GGC food prices increase for the 2007 year 402 and the 2008 year 404, in %/yr.

[0072] Food pricing percentage increases associated with the year 2007 402 is illustrated by a 2007 food price increase bar 410. The 2007 food price increase bar 410 shows that food prices increased by about thirty percent per year in the GCC. Food pricing percentage increases associated with the year 2008 404 is illustrated by a 2008 food price increase bar 420. The 2008 food price increase bar 420 shows that food prices increased by about forty percent per year in the GCC. One reason for this increase in GCC food pricing is illustrated in Figure 4B.

[0073] Figure 4B shows an Arab country food import bar chart 450 in accordance with an exemplary embodiment. The Arab country food import bar chart 450 has a country x-axis 45 1 and a food import amount y-axis 459. The country x- axis 45 1 depicts two country groups. One country group is an all Arab countries group 452, while the second country group is a GCC group 454. The food import amount y-axis 459 shows the dollar amount that food is imported for the all Arab countries group 452 and the GCC group 454, in billion dollars/yr. [0074] Food import amounts associated with the all Arab countries group 452 is illustrated by an all Arab countries food import bar 460. The all Arab countries food import bar 460 shows that food imports to all Arab countries are about 200 billion dollars per year. Food import amounts associated with the GCC group 454 is illustrated by a GCC food import bar 470. The GCC food import bar 470 shows that food imports to the GCC are about twenty-five billion dollars per year. The GCC imports about ninety percent of all imported foods. Thus, according to the GCC food pricing bar chart 400 and the fact that the GCC imports about ninety percent of all imported foods, there is a need for a more available food supply in the GCC to maintain or lower the food pricing per year. Although these charts arc shown specific to the GCC, the exemplary embodiments can be used anywhere where produced water is available for treatment.

10075] Figure 5 shows a vegetable crop salinity yield potential and compound tolerance chart 500 in accordance with an exemplary embodiment. This chart 500 shows statistical information that can be used in selecting potential crops to be grown in the agricultural unit 280 (Figure 2A) using the RO permeate stream 279 (Figure 2). Irrigation water quality has a profound impact on crop production. All irrigation water includes dissolvcr mineral salts, but the concentration and composition of the dissolved salts vary depending upon the irrigation water source. Too much salts reduces or even prohibits crop production, while too little salt reduces water infiltration, which indirectly affect crop growth.

[0076] The vegetable crop salinity yield potential and compound tolerance chart 500 has three main columns, which include a vegetable and row crops column 510. an electrical conductivity and yield potential column 520, and a rating column 530. The vegetable and row crops column 510 displays various crops, including vegetables and fruits, that can potentially be grown. Although some exemplary crops are shown in the vegetable and row crops column 510, the listing is not meant to be limiting.

[0077] The electrical conductivity and yield potential column 520 is further divided into four sub-columns, which include a one hundred percent yield column 522. a ninety percent yield column 524, a seventy-five percent yield column 526. and a fifty percent yield column 528. In each of these four sub-columns 522, 524, 526. and 528, the electrical conductivity based upon the irrigation water source is provided for each of the various crops and is given in millimhos per centimeter (mmhos/cm) units.

[0078] The rating column 530 is further divided into two sub-columns, which include a salt rating column 532 and a boron rating column 534. Both rating columns 532 and 534 provide sensitive or resistant ratings for each of the various crops. These ratings are provided as 'S'^: for sensitive, '"MS" for moderately sensitive, "'MT" for moderately tolerant. "T" for tolerant, and "VT" for very tolerant. Optimal crop production occurs when minimizing the energy used in reverse osmosis, producing crops that are at least moderately tolerant for boron, and producing crops that are at least moderately sensitive for salt. Based upon information provided in the chart, some f the exemplary crops that can be produced using the produced water treatment process 200 of Figures 2Λ and 2B include asparagus, red beet, cabbage, cauliflower, celery, scallop squash, zucchini squash, and tomato. The other listed crops also can be grown; however, the efficiency for crop growth may be reduced. Upon producing the crops, these crops are used to reduce food imports into the country; thereby saving dollars.

[0079] In summary, according to some exemplary embodiments, the produced water treatment process 200 of Figures 2Λ and 2B recovers greater than ninety percent of the produced water as low salinity, low selenium agricultural water and high quality potable water. This prevents environmental issues associated with disposal of the produced water by conventional processes. Λlso, according to some exemplary embodiments, the heavy metals and selenium is recovered in the produced water treatment process 200 of Figures 2A and 2B and is vitrified in a gasification unit; thereby producing a slag byproduct stream which can be used as construction aggregate.

[0080] Additionally, according to some exemplary embodiments, the produced water treatment process 200 of Figures 2A and 2B is a multi-train self- contained system that uses limited utility requirements (power only), truckable amounts of commodity chemical feeds (iron, ferric chloride, lime, sulfuric acid, coke, and fertilizer), and truckable amounts of useful byproducts (fruits, vegetables, brine shrimp, gasifier feedstock, gasifier flux, high purity salt, bromine rich salt, magnesium rich salt, and boric acid). The multi-train self-contained system also provides all potable water and agricultural water for a sustainable community; thereby allowing the plant to be located in multiple remote locations with only truck access and onsite power generation. According to some exemplary embodiments, the produced water treatment process 200 of Figures 2Λ and 2B avoids the cost and environmental risk of contaminated water injection, as used in conventional processes. Further, according to some exemplary embodiments, the produced water treatment process 200 of Figures 2A and 2B generates a positive revenue from the sale of agricultural products, brine shrimp, and mineral byproducts. [0081] According to some exemplary embodiments, the produced water treatment process 200 of Figures 2A and 2B consumes less energy, about fifty percent less energy, when compared to traditional seawater desalination plants due to the lower salinity in the produced water. According to yet more exemplary embodiments, the produced water treatment process 200 of Figures 2A and 2B produces no waste effluent stream since all the byproduct streams usable in commercial processes or markets. In some exemplary embodiments, the produced water treatment process 200 of Figures 2A and 2B allows net produced water removal from oil formations; thereby enabling more effective enhanced oil recovery production using carbon dioxide and nitrogen instead of water reinjection.

[0082] In still some exemplary embodiments, the produced water treatment process 200 of Figures 2A and 2B allows the entire brine evaporation pond to be utilized for brine shrimp production by using a continuous purge system and brine recirculation. According to some exemplary embodiments, the produced water treatment process 200 of Figures 2A and 2B removes essentially all the suspended solids, hardness, carbonates, and sulfates in the irrigation water; thereby, enabling the use of subsurface drip irrigation (SDI) since the potential for emitter plugging is climated and the sytem life is increased to over twenty years. The SDI system reduces evaporation losses to less than about five percent; thereby, minimizing agricultural water consumption, which is especially important in arid climates. The operation of the SDI system is known to people having ordinary skill in the art. Yet, in some exemplary embodiments, the produced water treatment process 200 of Figures 2A and 2B increases the brine shrimp production quantity at a constant reliable flow due to control of the brine pond at optimum conditions, which is at near indoor tank operation parameters as known to people having ordinary skill in the art. The brine pond has a predator free synthetic seawater.

[0083] One feature of the produced water treatment process 200 of Figures 2A and 2B includes a dissolved air flotation and settler system, which operates in an acidic environment, for removing emulsified oil, emulsified solids, and trace dissolved hydrocarbons from produced water using coke, or activated carbon, ferric chloride, and anionic flocculants. The dissolved air flotation and settler system recovers oil and produces a carbonaceous filter cake with an ash component high in iron and low in chloride, which is optimum for use in a gasification process. The dissolved air flotation and settler system recovers oil also produces an essentially organics free, solids free effluent water stream suitable for further processing to produce potable water and agricultural water.

10084] Another feature of the produced water treatment process 200 of

Figures 2A and 213 includes two stages of NF membranes in combination with an evaporator operating at an acidic pl l to treat the essentially organics free, solids free effluent water stream, mentioned above, and produce a stream concentrated in sclcnate and heavy metal, but low in nitrates, sulfates, carbonates, and oxygen. These two stages of NF membranes and the evaporator allow co-precipitation of selenium and heavy metals with iron; thereby, producing a low chloride filter cake. This filter cake is used in a gasification process and is an optimal gasification fiuxant. Additionally, the evaporator offgas can be treated with lime to produce potable water that meets quality standards.

[0085] Another feature of the produced water treatment process 200 of

Figures 2 A and 2B includes and air stripper, located downstream of a primary settler, and an iron chloride absorber which removes hydrogen sulfide from the offgas of the air stripper. The bottoms of the iron chloride absorber is used as a fiocculant in the primary setter and produces a filter cake that is iron rich. This filter cake can be used in a gasification process.

[0086J An additional feature of the produced water treatment process 200 of

Figures 2A and 2B includes a combination of acidic air stripping, NF hardness removal, and a low pressure drop RO membrane for removing boron. The RO membrane operates at basic conditions due to the upstream removal of calcium carbonate in the NF membrane. The boron is converted into ionic borate before entering the RO membrane, which facilitates the removal of boron. [00871 Another feature of the produced water treatment process 200 of

Figures 2A and 2B includes an NaCl crystallization and a low pressure drop RO membrane to separate the Boron from the salt; thereby allowing recovery of high purity boric acid. The NaCl crystallizer and the RO membrane operate at acidic conditions.

[00881 Another feature of the produced water treatment process 200 of

Figures 2A and 2B includes using only an RO membrane permeate water stream with gypsum soil addition in a subsurface drip irrigation system. This eliminates emitter plugging from hardness deposits and solids accumulation.

[0089] Another feature of the produced water treatment process 200 of

Figures 2A and 2B includes using the offgas from an iron chloride absorber, which includes carbon dioxide rich air. to enhance operation of the brine shrimp pond. This carbon dioxide rich air provides carbon dioxide and oxygen to the algae and brine shrimp.

[0090] Another feature of the produced water treatment process 200 of

Figures 2A and 2B includes a brine shrimp pond. The brine shrimp pond uses synthetic seawater, a continuous purge and contaminant removal system, a brine recirculation stream, and spray cooling to maintain the brine pond at optimum ranges for salinity, ions, and temperature.

[009 IJ Although the invention has been described with reference to specific embodiments, these descriptions are not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the invention will become apparent to persons of ordinary skill in the art upon reference to the description of the invention. It should be appreciated by those of ordinary skill in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures or methods for carrying out the same purposes of the invention. It should also be realized by those of ordinary skill in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. It is therefore, contemplated that the claims will cover any such modifications or embodiments that fall within the scope of the invention.

Claims

WHAT IS CLAIMED IS:Whal is claimed is:

1. A produced water treatment process, comprising: a produced water treatment facility producing a recovered oil stream, an agricultural water stream, and at least one produced water treatment tailings stream from an inlet produced water feed stream entering the produced water treatment facility, at least one minerals recovery system fluidly coupled to the produced water treatment facility, the minerals recovery system producing at least one mineral compound, at least one potable water stream, and at least one minerals recovery' tailings stream, wherein the produced water treatment tailings stream supplies a stream into the minerals recovery system.

2. The produced water treatment process of claim I, wherein at least one of the minerals recovery tailings stream is fed into a gasification system.

3. The produced water treatment process of claim 1 , wherein a first minerals recovery system is fluidly coupled to the produced water treatment facility and produces a first potable water stream, at least one mineral compound, and at least one minerals recovery tailings stream from a first produced water treatment tailings stream, the first produced water treatment tailings stream being discharged from an NF membrane positioned within produced water treatment facility.

4. The produced water treatment process of claim 3, wherein the mineral compound comprises at least one mineral compound selected from a group consisting of gypsum, calcium chloride, magnesium chloride, and sodium chloride.

5. The produced water treatment process of claim 3, wherein at least one of the minerals recovery tailings stream comprises iron sclenate.

6. The produced water treatment process of claim 1, further comprising: a brine shrimp pond fluidly coupled to the produced water treatment facility, wherein the brine shrimp pond produces a brine shrimp discharge stream from a second produced water treatment tailings stream, the second produced water treatment tailings stream being discharged from a RO membrane positioned within produced water treatment facility, the brine shrimp discharge stream feeds into a second minerals recovery system.

7. The produced water treatment process of claim 6. wherein the second minerals recovery system produces a second potable water stream, at least one mineral compound, and at least one minerals recovery tailings stream from the brine shrimp discharge stream.

8. The produced water treatment process of claim 7, wherein the mineral compound comprises at least one mineral compound selected from a group consisting of fertilizer, sodium chloride, boric acid, potassium chloride, sodium bromide, and silicon dioxide.

9. The produced water treatment process of claim 7, wherein at least one of the minerals recover}' tailings stream is recycled back to the brine shrimp pond.

10. The produced water treatment process of claim 6, wherein the second minerals recovery system comprises a second RO unit, the second RO unit operating at acidic conditions.

1 1. The produced water treatment process of claim 1. wherein the produced water treatment facility comprises: an oil and metals removal system, wherein the inlet produced water feed stream enters the oil and metals removal system and produces the recovered oil stream, a third produced water treatment tailings stream, and an oil and metals removal discharge stream; a UF membrane fluidly coupled to the oil and metals removal system, the oil and metals removal discharge stream entering the UF membrane and producing a UF permeate stream and a UF non-permeate stream, the UF non-permeate stream being recycled to the oil and metals removal system; a NF membrane fluidly coupled to the UF membrane, the UF permeate stream entering the NF membrane and producing a NF permeate stream and a first produced water treatment tailings stream; and a RO membrane fluidly coupled to the NF membrane, the NF permeate stream entering the RO membrane and producing a RO permeate stream and a second produced water treatment tailings stream.

12. The produced water treatment process of claim 1 1, wherein the first produced water treatment tailings stream enters a first minerals recovery system.

13. The produced water treatment process of claim 12, wherein the first minerals recovery system produces at least one mineral selected from a group consisting of gypsum, calcium chloride, magnesium chloride, and sodium chloride.

14. The produced water treatment process of claim 1 1. wherein the second produced water treatment tailings stream enters a brine shrimp pond producing a brine shrimp pond discharge stream, the brine shrimp discharge stream entering a second minerals recovery system.

15. The produced water treatment process of claim 14, wherein the second minerals recovery system produces at least one mineral selected from a group consisting of fertilizer, sodium chloride, boric acid, potassium chloride, sodium bromide, and silicon dioxide.

16. The produced water treatment process of claim I I , wherein the RO permeate is supplied to an agricultural unit the agricultural unit producing one or more food crops.

17. The produced water treatment process of claim 1 1 , wherein the RO membrane operates at basic conditions.

18. The produced water treatment process of claim 1 1 , wherein the oil and metals removal system comprises: a first settler producing a first settler discharge stream; an air separator producing an air separator discharge stream and an air separator overheads stream from the first settler discharge stream; a second settler for receiving the air separator discharge stream; and an iron chloride absorber for receiving the air separator overheads stream and producing an iron chloride absorber overheads stream and an iron chloride absorber bottoms stream, wherein the iron chloride absorber bottoms stream is routed to the first settler.

19. The produced water treatment process of claim 18. wherein the iron chloride absorber overheads stream comprises carbon dioxide and oxygen and is routed to a brine shrimp pond.

20. Λ method for operating a produced water treatment process, comprising: providing a produced water treatment facility producing a recovered oil stream, an agricultural water stream, and at least one produced water treatment tailings stream from an inlet produced water feed stream entering the produced water treatment facility. fluidly coupling at least one minerals recovery system to the produced water treatment facility, the minerals recovery system producing at least one mineral compound, at least one potable water stream, and at least one minerals recovery tailings stream, wherein the produced water treatment tailings stream supplies a stream into the minerals recovery system.

21. The method of claim 20, wherein at least one of the minerals recovery tailings stream is fed into a gasification system.

22. The method of claim 20, wherein a first minerals recovery system is fluidly coupled to the produced water treatment facility and produces a first potable water stream, at least one mineral compound, and at least one minerals recovery tailings stream from a first produced water treatment tailings stream, the first produced water treatment tailings stream being discharged from an NF membrane positioned within produced water treatment facility.

23. The method of claim 22. wherein the mineral compound comprises at least one mineral compound selected from a group consisting of gypsum, calcium chloride, magnesium chloride, and sodium chloride.

24. The method of claim 22, wherein at least one of the minerals recovery tailings stream comprises iron selenate.

25. The method of claim 20, further comprising: fluidly coupling a brine shrimp pond to the produced water treatment facility, wherein the brine shrimp pond produces a brine shrimp discharge stream from a second produced water treatment tailings stream, the second produced water treatment tailings stream being discharged from a RO membrane positioned within produced water treatment facility, the brine shrimp discharge stream feeds into a second minerals recovery system.

26. The method of claim 25, wherein the second minerals recovery system produces a second potable water stream, at least one mineral compound, and at least one minerals recovery tailings stream from the brine shrimp discharge stream.

27. The method of claim 26, wherein the mineral compound comprises at least one mineral compound selected from a group consisting of fertilizer, sodium chloride, boric acid, potassium chloride, sodium bromide, and silicon dioxide.

28. The method of claim 26, wherein at least one of the minerals recovery tailings stream is recycled back to the brine shrimp pond.

29. The method of claim 25, wherein the second minerals recover)' system comprises a second RO unit, the second RO unit operating at acidic conditions.

30. The method of claim 20. wherein the produced water treatment facility comprises: an oil and metals removal system, wherein the inlet produced water feed stream enters the oil and metals removal system and produces the recovered oil stream, a third produced water treatment tailings stream, and an oil and metals removal discharge stream: a UF membrane fluidly coupled to the oil and metals removal system, the oil and metals removal discharge stream entering the UF membrane and producing a UF permeate stream and a UF noπ-permeate stream, the UF non-permeate stream being recycled to the oil and metals removal system; a NF membrane fluidly coupled to the UF membrane, the UF permeate stream entering the NF membrane and producing a NF permeate stream and a first produced water treatment tailings stream; and a RO membrane fluidly coupled to the NF membrane, the NF permeate stream entering the RO membrane and producing a RO permeate stream and a second produced water treatment tailings stream.

31. The method of claim 30, wherein the first produced water treatment tailings stream enters a first minerals recovery system.

32. The method of claim 31 , wherein the first minerals recovery system produces at least one mineral selected from a group consisting of gypsum, calcium chloride, magnesium chloride, and sodium chloride.

33. The method of claim 30. wherein the second produced water treatment tailings stream enters a brine shrimp pond producing a brine shrimp pond discharge stream, the brine shrimp discharge stream entering a second minerals recovery system.

34. The method of claim 33, wherein the second minerals recovery system produces at least one mineral selected from a group consisting of fertilizer, sodium chloride, boric acid, potassium chloride, sodium bromide, and silicon dioxide.

35. The method of claim 30. wherein the RO permeate is supplied to an agricultural unit, the agricultural unit producing one or more food crops.

36. The method of claim 30, wherein the RO membrane operates at basic conditions.

37. The method of claim 30, wherein the oil and metals removal system comprises: a first settler producing a first settler discharge stream; an air separator producing an air separator discharge stream and an air separator overheads stream from the first settler discharge stream; a second settler for receiving the air separator discharge stream; and an iron chloride absorber for receiving the air separator overheads stream and producing an iron chloride absorber overheads stream and an iron chloride absorber bottoms stream, wherein the iron chloride absorber bottoms stream is routed to the first settler.

38. The method of claim 37, wherein the iron chloride absorber overheads stream comprises carbon dioxide and oxygen and is routed to a brine shrimp pond.