WO2008071809A1 - Refinements made to drinking water plants for regeneration of aquifers contaminated by nitrates and functioning procedure thereof - Google Patents

Abstract

The invention relates to a new type of drinking water plant designed for regenerating aquifers and the functioning procedure thereof with application of set concepts for general purification of waters as the initial stage of fine filtering and other methodologies which to date have not been applied to this technical sector enabling the plant to be totally adapted to the type of water to be purified, said adaptation depending on the greater or lesser presence of extraneous substances, or rather the greater or lesser concentration thereof in said water, thereby extracting mineral or organic loads, with abundant presence of nitrates to be processed by formulation of fertilisers for subsequent application in nearby agricultural lands.

Description

 "IMPROVEMENTS INTRODT-πrtoÓS-SfcMí & S

WATER TREATMENT PLANTS FOR THE REGENERATION OF NITRATED CONTAMINATED AQUIFERS AND THEIR PROCEDURE

OF OPERATION "

The invention relates to a new type of water treatment plant designed for the regeneration of aquifers and their operating procedure with application of certain concepts of general water treatment as a preliminary phase of fine slabs and other methodologies that have not been applied to this. technical sector, which allow a perfect adaptation of the plant to the type of water to be purified according to the greater or lesser presence of foreign substances, or to the greater or lesser concentration of the same in said water, extracting mineral and organic loads, accompanied by abundant presence of nitrates that will be managed by formulating fertilizers for subsequent application in nearby arable land.

Until now, pig and cattle hog farms represent an important contribution to the national GDP, although due to technological hazards they have moved away from compensated agricultural operations, which often leads to farms without a sufficient territorial base for the use of slurry. generated by these farms.

This reality together with the massive application of mineral fertilizers to the soil often raises severe environmental impacts, where the water vector is usually affected by nitrate contamination, microbial load, presence of metals and other contaminating substances. The aforementioned contamination by nitrates of surface water and groundwater from agricultural sources is considered, today, as the main problem of pollution of diffuse origin recorded by the European Union. The situation in Spain and some autonomous communities such as Catalonia is particularly serious due to the harmful effects it generates, a circumstance that the European Commission has repeatedly denounced in front of the administrations both Catalan and Spanish, for breach of Directive 80/778 / EC.

The excessive contamination of water resources by the presence of nitrates invalidates the application of these waters for mouth consumption, which is why the application of preventive and corrective measures is imposed on those activities directly or indirectly responsible for this impact. It is, therefore, a decontamination of water resources that allows its use as water for basic consumption by the populations directly affected. The routes currently used for the supply of drinking water to areas affected by nitrate pollution are mainly:

- Via 1: Reservoir, pumping of the water collected in said reservoir, water treatment station, regulating tank, pumping to the consumption zone, sometimes covering large pumping distances.

- Via 2: Water tanks and water transport to the consumption zone, by cisterns on motorized vehicles. The alternative to the supply routes described in the previous paragraph is the object of the present invention, which proposes the action ^" in situ" for any population level, which must be provided with special emphasis on those lower levels, especially populations of less than 500. From track 1, a significantly unfavorable cost-level evaluation is given, given its characteristics of investment and operating expenses, the investment being in a situation of long-term amortization, as a consequence of its intensity, (high ratio in the ratio: investment practiced, number of inhabitants served).

Via 2 is characterized by giving merely punctual responses to critical situations of scarcity, associated with the service, significantly increasing the real cost of the water supplied.

It is due to these factors that the alternatives consisting of water potabilization actions in areas close to the consumption areas gain ground, as opposed to those consisting of applying transport solutions at a distance (channeling and / or roads).

The problem arises very often when it comes to adapting contaminated water for mouth consumption for small populations, since it becomes impossible or practically impossible to carry out the reasonable amortization of road 1, which implies the need for disproportionate subsidies, in base to general budgets, charging the cost of the investment on a significantly expanded population, and not directly enjoying the service. On the other hand, the "principle of subsidiarity" indicates that a solution that would have been marked would have to be applied for territoriality and self-sufficiency. This will force an economically easily assumable and local effort on the part of the population directly affected, which could benefit from the water supply for mouth consumption, from their own water resources after being subjected to a corrective purification treatment.

The dimension of the problem raised together with other sanitary requirements that the law insists on stressing, involve the search for solutions that are technically feasible, easy to operate, with high repetitiveness and with sufficient controls in real time. All this in order to ensure at all times the character of potability.

With the proposed invention basically two types of health risks would be avoided:

- About the respiratory system:

The binomial [hemoglobin - nitrated waters] easily leads to the fixation of oxygen during respiration. Especially sensitive population: children and the elderly. - About the digestive system:

The presence of nitrated waters in the digestive system favors the formation of nitrosamines (especially on protein bases).

That is why the solution recommended "in situ" allows to undertake a double objective:

1) Provide drinking water for mouth consumption in a sustainable manner, avoiding problems of morbidity and mortality associated with nitrated waters.

2) The regeneration of aquifers contaminated by nitrates (remediation). Within the techniques of denitrification applicable ^ΛΛ in situ "the physical-chemical separation has been chosen, with the use of membranes that allow the potabilization of the mentioned waters, converting it into water valid for mouth consumption, simultaneously allowing the recovery of aquifers affected by nitrate contamination.

A non-destructive method of nitrates is applied that leads to the obtaining of a saline concentrate, which has to be managed and treated in a different way; considering the reuse as a basic objective of its management.

The volumes of saline concentrate (between 10 and 20% of the total produced water) will present a concentration between 5 and 10 times higher than the concentration of the salts initially present in the water to make it drinkable. As a consequence of the almost total elimination of the salts initially present through the application of tangential filtration, it is necessary to carry out a refining of the salt, making a mixture of deionized water from the membranes exit with raw water without osmotization, in order to recover those minimum saline content that must be present in the water for mouth consumption.

Another purpose of the invention is the reduction of the hardness of the water due to the presence of calcium and magnesium, in order to obtain drinking water of optimum characteristics so that its mineralization is weak, and therefore avoiding the serious problems that the lime deposit causes in the pipes and interior installations in the subscriber's house.

Another purpose of the invention is that the water treatment plant object of the invention will be manufactured on a container element or chassis easily transportable in the platform of a truck or in a trailer, with which it will be possible in the first place its rapid construction in an industrial warehouse equipped with all the means and protected from any adverse climatic situation, and in second place it will be able to move with great ease, being implemented almost instantaneous way to its taken to the vicinity of the aquifer.

In addition, the compact and confined structure of the plant protects it from possible vandalism, thus ensuring the functionality of it.

The stages that make up the functioning of the proposed water treatment plant are the following: Stage n ° 1 - Physical-chemical treatment Stage n ° 2 - Pre-treatment 1 of reverse osmosis Stage n ° 3 - Pre-treatment 2 of osmosis Reverse Stage n ° 4 - Reverse osmosis treatment Stage n ° 5 - Final chlorination and sanitization

Other details and characteristics will become apparent in the course of the description given below in which reference is made to the figures that accompany this report in which is shown for illustrative but not limited to a practical implementation of the invention. Following is a detailed list of the main elements that make up the proposed water treatment plant, accompanied by a number found in the attached figures; (10) water treatment plant, (11) 20-foot container, (12) 10-foot container, (13) auxiliary generator, (14-15) intermediate tanks, (16) pump, (17) electrical panel, (18) work table, (19) mechanical filter, (20) micro-filtration tanks, (21) product dosing tanks, (22) osmosis membranes, (23) pump, (24) hypochlorite reservoir, (25) carbon filter,

(26) carbon filter by-pass (25), (27-28) dosing pumps, (29) automatic regulation means, (30) injection system, (31) reducing agent reservoir, (32) reservoir acid, (33-34) dosing pumps, (35) automatic regulation system, (36) injection system, (37) anti-fouling tank, (38-39) pumps, (40) automatic regulation system, ( 41) injection system, (42) safety micro-filter, (43) by-pass, (44) pressure gauge, (45) flowmeter, (46) micro-filter by-pass (42), (47) reservoir osmotized water, (48-49) upper and lower levels in the reservoir (47), (50) reject reservoir, (51) control panel, (52) pH meter, (53) pressure transducer, (54) flowmeter, (55) impulse pump, (56) anti-return valve, (57) pump by-pass (55), (58) reverse osmosis membrane, (59) conductimeter, (60) flowmeter, (61) ) sample taking, (62) ph meter, (63) conductimeter, (64) manometer, (65) cauda limetro, (66) confluence point, (67) conductimeter, (68) impulse pump, and (69) external deposit.

Figure 1 is a flow chart illustrative of the operation of the water treatment plant (10), which includes the different stages.

Figure 2 is a schematic plan distribution of a possible water treatment plant (10) mounted in a container (11) of 20 feet, with its main elements written on it. Figure 3 is a schematic layout of another possible water treatment plant (10) mounted in a container (12) of 10 feet, with its main elements written on it.

In one of the preferred embodiments of what is the object of the present invention, the water treatment plant (10) includes a container element (11-12), 10 or 20 feet in length respectively, which allows it to be moved by a simple truck, loading it as if it were a container, or said container placed on a platform with the conventional means for coupling to the tractor unit of the truck to allow its operation completely autonomous, as can be seen in figures n ° 2 and 3.

The water treatment plant (10) is equipped with an auxiliary generator (13) that supplies energy to the elements that drive the water flow, such as pumps

(16-23), as well as any other secondary element, such as probes, electro-valves and other measuring and control elements governed by an electrical panel (17). In turn the water treatment plant (10) within a stage I ^to call physicochemical treatment, see figure 2, performing the function of thin slab, it has intermediate tanks (14-15) for assuming that the waters to be treated have important contributions in terms of suspension, in the event that said waters do not contain suspended matter, they pass directly to the following stages 2 ^a , 3 ^a and 4 ^a .

In general, the waters to be treated will come from wells, rivers, aquifers, groundwater and similar.

It is therefore a matter of eliminating insolubles of organic matter and mineral matter from the drinking water that enters the plant (10) and goes to the deposits (14-). 15), using decantation flocculation coagulation techniques using chemical products from the tanks (21) which are poured into the mechanical filter.

(19) proceeding therein to the so-called fine slab, see figure No. 2. The chemical products used will be the following:

- aluminum chloride (monomer); I

- aluminum hydroxychloride (monomer and polymers); and / or aluminum hydroxychloride sulphate (monomer and polymers); I

- iron (III) chloride; I

- iron (III) chlorosulfate; I

- aluminum sulfate; I

- iron (II) sulfate; and / or iron (III) sulfate; I

- anionic polyoacylamides (strong, medium or weak)

; I

- cationic polyoacylamides (strong, medium or weak, and / or - non-ionic polyacrylamides, and / or

- other related products with these types of structures and chemical compositions.

After this stage of decantation of the water, they are obtained as by -product a primary sludge that must be managed properly, and clarified water (without suspended material) that enter into the 2nd stage, which we call pretreatment 1 reverse osmosis, wherein microbicidal products such as sodium hypochlorite, from the reservoir (24) or sanitizing techniques by radiant energy such as lamps are applied ultraviolet disinfecting water, see figure 3, when necessary, the resulting mixture (water + sodium hypochlorite) through the carbon filter (25) in order to eliminate recalcitrant organic molecules (halomethanes, pesticides and others), as remnants of unreacted chlorine.

The dosage of sodium hypochlorite includes the reservoir (24) and the dosing pumps (27-28), together with an automatic regulation and an injection system (29-30), not shown in the figures. In the event that (water + sodium hypochlorite) from the mechanical filter (19) does not require filtering through the carbon filter (25), a by-pass (26) is provided so that it does not pass through the filter

(25) In both cases, at the outlet of the carbon filter (25), the water is prepared for the reverse osmosis pre-treatment or to by-pass the membrane system and be added on the osmotized water, trying to get replacement saline in hygienic conditions.

In stage 3 ^a a water homogenization process is followed, in which three families of different reagents will be applied:

- reducers from the tank (31); I

- acidifiers from the tank (32); I

- anti-foulants from the tank (33).

The purpose of these reagents is to ensure the total elimination of oxidizing agents that can damage the membranes, by means of the use of reducing agents and the elimination of volatile hardness by means of acidifying agents and the control anti-deposition of saline hardness with the dosage of anti -crushers. The dosage of the reducing agent and the acid deposits are used (31-32-37) Individually provided with the pumps (33-34-38-39), see figure No. 1 and the corresponding agitator, with the aid of automatic regulation (35) and an injection system (36) not shown in the figures. As products with reducing effect are applied for example:

- sodium sulfite; I

Sodium acid sulphite (sodium hydrogensulfite); and / or - sodium disulfite (potassium metabisulfite or potassium pyrosulfite); I

- calcium sulfite.

As products with an acidifying effect, for example:

- acetic acid; I

- hydrochloric acid; I

- phosphoric acid; I

- sulfuric acid.

For the dosing of anti-fouling products, the antifouling tank (37) equipped with a stirrer and metering pumps (38-39) is used, see figure 3, with an automatic control system (40) and a system of injection (41), not shown in the figures. Products with antifouling effect are applied, such as:

- potassium dihydrogen phosphate; I

- sodium dihydrogen phosphate; I

- tripotassium phosphate; and / or - trisodium phosphate; I - sodium hydrogen phosphate; I

- potassium hydrogen phosphate; I

- tetrapotassium pyrophosphate; I

- sodium pyrophosphate; and / or - potassium tripolyphosphate; I

- sodium tripolyphosphate; I

- sodium hexametaphosphate; I

- potassium hexametaphosphate; I

- phosphoric acid.

The water mixture with reducer, acid and anti-fouling agent then passes to the tanks (20) and then to a safety micro-filter (42), see figure 2, equipped with the corresponding by-pass (43). at this point stage n ° 3.

Starting from this point the 4th stage, in which the liquid passes by the pH meter (52) which regulates the metering pump acid (34) and can be sampled for external control, then passing water a pressure transducer (53) provided with its pressure gauge (54). The function of the transducer (53) is to stop the delivery pump (55) if it runs out of water, then passing through the conductimeter (54), provided before the pump (55) a non-return valve (56) . The impulse pump (55) incorporates a by-pass (57) with automatic and / or manual regulation, depending on the frequency inverter incorporated in the control panel (51). Before the water enters the reverse osmosis membrane (58) it passes through the pressure transducer (59) which will regulate and inform the control panel (51) of the reading values. In the reverse osmosis membrane (58) there is a reverse phenomenon to normal osmosis, which is obtained by exerting a pressure above the osmotic pressure on the concentrated solution, so that nitrate and contaminant separation occurs in it. Well the water is rejected.

The purified water at the outlet of the membrane (58) passes through a conductimeter (59) and flow meter (60), finally passing through the sampling (61), or even a de-dosed water tank (47) equipped with a level game

(48-49), provided (47) of a pH meter (62) and a flowmeter (63) connected to the control panel (51), if the water in the tank (47) presents the correct parameters measured by the meter pH (62) and conductimeter (63) from the control panel (51) the water passes from the tank (47) to an external tank (69) pumped by the impulse pump (68), then the water passes in what we will call 5 ^to stage, to a chlorination by means of hypochlorite coming from the tank (24), which is pumped by the impulsion pump (27) to the treated water tank (47).

Alternatively, depending on the nature of the water leaving the osmosis membrane (58), it is rejected and through the corresponding conduit it goes to a reject tank (50) through a conductimeter (67) connected to the control panel (51), or it is re-sent to the point before the impulse pump (55) passing through the manometer (64) and the flowmeter (65) until reaching the point

(66)

Finally and before finishing the stage, the water goes through a conventional washing and displacement system formed by a tank, a pump, a stirrer, some low pressure connection pipes with the corresponding valves, equipped with the system flowmeters, thermometers, manometers.

The electrical control panel (51) controls for all stage 4 ^to work automatically, for this and as can be seen in figure n ° 3 is directly connected to a pH meter (52) and a flow meter (53) located at the inlet and outlet of the pressure switch and pressure gauge (43-44) respectively. Having sufficiently described the present invention in correspondence with the appended figures, it is easy to understand that any modifications of detail that may be considered convenient may be introduced therein, provided that the essence of the invention summarized in the following claims is not altered.

Claims

R E I V I N D I C A C I O N E S: I ^a - "INTRODUCED IN PLANTS WATER TREATMENT WATER FOR REGENERATION Aquifer CONTAMINATED BY NITRATES IMPROVEMENTS AND METHOD OF OPERATION" of the type using physico-chemical methods with media manufactured ^Λλ in situ ", reservoirs, ponds and other elements, through civil works and directly on the chosen land and that are capable of water treatment contaminated with foreign substances but assessed and with fixed values, characterized in that the water treatment plant (10) includes means of adapting it to the type of water to be purified according to the greater or lesser presence of foreign substances, means of extracting nitrates and finally means for balancing in nutrient that allows the application of rejection of fertirrigations in crops near the site of the water treatment plaza. 2 ^a - "IMPROVEMENTS INTRODUCED IN THE WATER TREATMENT PLANTS FOR THE REGENERATION OF NITRATED CONTAMINATED AQUIFERS AND THEIR OPERATING PROCEDURE" according to the I ^a claim, characterized in that the means of adaptation of the water treatment plant (10) to the type of water incoming are physical-chemical means. 3 ^a - "IMPROVEMENTS INTRODUCED IN THE WATER TREATMENT PLANTS FOR THE REGENERATION OF NITRATED CONTAMINATED AQUIFERS AND THEIR OPERATING PROCEDURE" according ^to claim I, characterized in that the operating procedure of the water treatment plant (10) comprises the following steps : - stage 2 ^a : pre-treatment 1 of reverse osmosis; - stage 3 ^a : pre-treatment 2 of reverse osmosis; - stage 4 ^a : reverse osmosis treatment; Y - stage 5 ^a : final chlorination and sanitization. 4 ^a - "IMPROVEMENTS INTRODUCED IN THE WATER TREATMENT PLANTS FOR THE REGENERATION OF AQUIFERS CONTAMINATED NITRATE AND METHOD OF OPERATION "according to I and 3rd claims, characterized in that in step Pretreatment 1 reverse osmosis microbicides products are applied, such as sodium hypochlorite, from a reservoir (24) or hygienization techniques using radiant energy such as UV lamps adapted to disinfect water, and optionally the resulting mixture (water + sodium hypochlorite) passes through a carbon filter (25) adapted to remove recalcitrant organic molecules (halomethanes, pesticides, and others) and remains of unreacted chlorine, provided by a by-pass (26) in the said filter (25), in the case that the (water + sodium hypochlorite) does not require filtering, at the end of this stage the water enters in the pre-treatment of osmosis or it passes to the membrane system and is added on the osmotized water, trying to achieve saline replacement under hygienic conditions. 5 ^a _ "IMPROVEMENTS INTRODUCED IN THE WATER TREATMENT PLANTS FOR THE REGENERATION OF NITRATED CONTAMINATED AQUIFERS AND THEIR OPERATING PROCEDURE" according to the 4 ^to claim, characterized in that dosing pumps for microbicide products are included (26-27) , together with an automatic regulation and an injection system (29-30). 6 ^a - "IMPROVEMENTS INTRODUCED IN THE WATER TREATMENT PLANTS FOR THE REGENERATION OF AQUIFERS POLLUTED BY NITRATES AND ITS PROCEDURE OF OPERATION "according to the I ^to claim, characterized in that in the phase of Pre-treatment 2 of reverse osmosis a water homogenization process is followed in which three families of reagents will be applied: - reducers, coming from the tank (31); I - acidifying agents, coming from the tank (32); I - anti-fouling, from the tank (37). 7 ^a - "IMPROVEMENTS INTRODUCED IN THE WATER TREATMENT PLANTS FOR THE REGENERATION OF AQUIFERS CONTAMINATED BY NITRATES AND THEIR PROCEDURE OF OPERATION "according to I and 3rd claims, characterized in that in phase 2 Pretreatment reverse osmosis the following products are used as reducing effect: - sodium sulfite; I Sodium acid sulphite (sodium hydrogensulfite); I - sodium disulfite (potassium metabisulfite or potassium pyrosulfite); I - calcium sulfite. g ^a _ "INTRODUCED IN PLANTS PURIFICATION OF WATER IMPROVEMENTS FOR REGENERATION contaminated aquifers by nitrates and its operation procedure" as the I and 3rd claims, characterized in that in the Pre-Treatment 2 of reverse osmosis they use the following as acidifying products: - acetic acid; and / or - hydrochloric acid; I - phosphoric acid; I - sulfuric acid. 9 - according to I and 6th claims "INTRODUCED IN PLANTS WATER TREATMENT WATER FOR REGENERATION Aquifer CONTAMINATED BY NITRATES AND METHOD FOR OPERATING IMPROVEMENTS" characterized in that phase Pretreatment 2 reverse osmosis they use the following as antifouling products: - potassium dihydrogen phosphate; and / or - sodium dihydrogen phosphate; I - tripotassium phosphate; I - trisodium phosphate; I - sodium hydrogen phosphate; I - potassium hydrogen phosphate; and / or - tetrapotassium pyrophosphate; I - sodium pyrophosphate; I - potassium tripolyphosphate; I - sodium tripolyphosphate; I - sodium hexametaphosphate; and / or - potassium hexametaphosphate; I - phosphoric acid. 10 - "INTRODUCED IN THE PURIFICATION OF WATER PLANTS IMPROVEMENTS FOR REGENERATION contaminated aquifers by nitrates and its operation procedure" as I ^to claim, characterized in that in the 4th stage the liquid passes through the pH meter (52 ) that regulates the acid dosing pump (34), being able to take samples for external control, then passing the water through a pressure transducer (53) provided with its pressure gauge (54) the function of the transducer (53) is to stop the pump of impulsion (55) if it runs out of water, then passing through the conductimeter (54), provided before the pump (55) a non-return valve (56), the pump drive (55) incorporates a by-pass (57), with automatic and / or manual regulation , depending on the frequency converter incorporated in the control panel (51), before the water enters the reverse osmosis membrane (58) passes through the pressure transducer (59), which will regulate and inform the control panel (51). ) of the reading values. 11 ^a - "IMPROVEMENTS INTRODUCED IN THE WATER TREATMENT PLANTS FOR THE REGENERATION OF AQUIFERS CONTAMINATED BY NITRATES AND THEIR PROCEDURE OF OPERATION "according to I ^a and 10 ^to claims, characterized in that in the reverse osmosis membrane (58) a reverse phenomenon occurs to normal osmosis, which is obtained by exerting on the concentrated solution a pressure higher than the osmotic pressure, so that the separation of nitrates and pollutants occurs in it or the water is rejected. 12 ^a - "IMPROVEMENTS INTRODUCED IN THE WATER TREATMENT PLANTS FOR THE REGENERATION OF AQUIFERS CONTAMINATED BY NITRATES AND THEIR PROCEDURE OF OPERATION "according to I ^a and 10 ^to claims, characterized in that the water already purified at the exit of the membrane (58) goes through a conductimeter (59) and a flow meter (60), finally passing through the sampling (61) or to a deionized water tank (47) equipped with a set of levels (48-49), provided (47) with a pH meter (62) and a meter (63) connected to the control panel (47). 51), if the water in the tank (47) has the correct parameters measured by the pH meter (62) and conductimeter (63) from the control panel (51) the water passes from the tank (47) to an external tank (69), pumped by the drive pump (68); if the parameters measured by the control panel (51) through (62-63) in the deposit (47) is not correct, the water passes into what we will call step 5 ^to a chlorination by hypochlorite from the reservoir (24), which is pumped by the pump drive (27), up to the deionized water tank (47), alternatively and according to the nature of the water leaving the osmosis membrane (58) it is rejected and through the corresponding conduit it goes to a reject tank (50), passing through a conductimeter (67), connected to the frame. 13 - "INTRODUCED IN PLANTS PURIFICATION OF WATER IMPROVEMENTS FOR REGENERATION Aquifer CONTAMINATED BY NITRATES AND METHOD OF OPERATION" according to I and 3rd claims, characterized in that the water treatment plant (10) is mobile and modular nature , incorporating all the elements in a container (11-12) and is self-sufficient when incorporating an electromotive force generator (13).