WO1994021349A1 - Flocculant composition for removing trihalomethane and its precursors - Google Patents

Abstract

This invention relates to a flocculent composition which so functions as an effective flocculant for flocculating and removing floating matter and detrimental metals when added to industrial wastes, sewage, raw water of service water, etc., removes effectively THMs and their precursors, and serves as a water purification agent. The present invention provides a novel flocculant composition which contains water-soluble aluminum salts, water-soluble iron salts and water-soluble magnesium salts in the proportions of Al, Fe, and Mg of 1, 0.01 to 2, and 0.01 to 2, respectively, in terms of atomic weight, and the sum of their oxides, Al2O3, Fe2O3, and MgO, amounts to 1 to 15 wt%.

Description

 Coagulant composition excluding trihalomethane and its forerunner substances

 The present invention relates to the field of purifying various industrial wastewaters such as metals, fibers, and papermaking, foods, domestic wastewaters such as municipal sewage, etc., and tap water.

 Background art

In general, there are inorganic and organic g-collectors. The former includes aluminum oxide (M ₂ (S0-) ₃ ), polyaluminum chloride (hereinafter referred to as PAS), and the latter includes compounds of various polymers. The coagulant composition of the present invention (hereinafter, referred to as composition) belongs to the inorganic type.

 An inorganic flocculant is required to have a high flocculating effect on suspended matter and a low residual amount of harmful metals and aluminum, iron, etc. in the treated water. Low residual amount is required even in water source water.

 In water source water treatment, aluminum-based inorganic coagulants are often used, and there is a problem that trace amounts of aluminum remain in the treated water, which is said to be the cause of Alheimer's disease.

X. CHC1 _3, CHCl ₂ Br in the water of the water supply is now, CHClBr _2, CHBr., Door Riharo meta emissions (less than THMs and abbreviation) of equal if there is a problem that there are, in terms of these are health Has been viewed as a global issue by

 In general, inorganic aluminum-based coagulants are used in the treatment of tap water, so that these substances such as THMs and Humic Acid must be removed. Have difficulty,

To solve this, ozone or ozone is not used without chlorine sterilization, which causes THHs formation. Some oxide sterilization method that by the CI0 ₂ or the like is試図are used. However, these disinfectants have problems that their safety has not been approved and their processing costs are expensive.

 Purpose of the invention

 INDUSTRIAL APPLICABILITY The present invention is added to industrial and industrial wastewater, domestic wastewater, etc., and acts as an effective flocculant for flocculation of suspended solids and removal of harmful metals, and at the same time, effectively removes THMs and their precursors. It is an object of the present invention to provide a flocculant composition to be used as a water purification agent for water supply and the like.

 Summary of the Invention

The present inventors have conducted long-term test research to achieve the technical background and problems as described above and the object thereof, and as a result, the water-soluble aluminum salt, the water-soluble iron salt, and the water-soluble magnesium salt were determined in atomic ratio. Fe 0 · 01-2 to al 1, to 2, contains Hg 0.01 to 2, the oxide _{A1 2 0 3, Fe 2 0} 3, novel scavenger is the sum of HgO 1 to 15 wt% We have found a surprising fact that the use of the composition can effectively solve the problem. Composition raw materials

A water-soluble salt of aluminum, iron, or magnesium is used as a raw material of the composition of the present invention. These can also be used in the form of solids or solutions such as anhydrides, hydrates and double salts. In addition, a solution of a reaction product obtained by treating a metal of aluminum, iron, or magnesium alone or a mixture thereof with a mineral acid such as hydrochloric acid, nitric acid, and sulfuric acid, or by drying the solution. the resulting anhydride, if hydrates specific examples, as the A1 salt A1 -. 61 ^ 0, A1 (N0 3) 3, Al 2 (sO,) a Al 2 (S0 -18H 2 0, A1 _{(N1) (S0,) 2} -18H 2 0 , etc., as the Fe salt rather then preferred trivalent Fe _{salt, FeC] 3, FeCl 3 -} 6H 2 0, Fe (N0 3) 3, Fe 2 (S0 _{4) 3 Fe 2 (S0 'xH z 0} , FeiNH ^) (S0 4) 2 * 6 ~ 12H 2 0 or a divalent iron salt FeSO, - 7H _Z can that you use the is a 0, etc. in the oxidation state environment. Is an H _K salt _{MgCl 2, MgC] 2 * 6H} 2 o, MgSO MgS0 4 * 7H 2 anhydride such as 0, there is hydrates. Double salt.

Mineral acid decomposed products of minerals containing Al, Fe and Hg can also be used. For example vermiculite (Verniculite) typically A 1 ₂ 0 _{3] 0~182, Fe 2 0 3 10~:} .? 18;, containing MgO 5-202, other oxides and moisture, etc. 44-75 .

Mineral acid decomposition products of these minerals can be used.

 Coagulant composition

The composition of the present invention coagulant, Fe 0.01 to 2 with respect to Al 1 in the atomic weight ratio, contains Hg 0 · 0Ι~2, its oxide _{A1 2 0 3, Fe 2 0} 3, the sum of HgO is 1-15 % The composition of% by weight is appropriate, and the effect is small outside this range. Formulations of these compositions are prepared by mixing various water-soluble Al, Fe, Mg or by adding decomposed products of Al, Fe, Mg-containing minerals and water-soluble Al, Fe, Mg salts.

 How to use flocculant

 The composition of the present invention is used in the same manner as a general inorganic flocculant. Although it can be used as a solid mixture, it is better to use it as an aqueous solution.

Add the composition solution to the wastewater and source water while stirring, adjust the pH to about 7, stir the mixture, and allow to separate and separate suspended matters and other substances. Amount of composition used The use amount of the composition of the present invention varies depending on the degree of pollution of wastewater and source water, the degree of S, and the like, but the overall high purification effect is as follows.

 With a composition of Fe 0.1-0.3 and Ηκ 0.1-0.3 with respect to the atomic weight ratio Al 1, the total amount of oxides is 5-10 weight%, and about 50-300ΡΡΒ is added to the wastewater and source water. It is effective to use.

 The invention's effect

 Aggregation effect

 Common inorganic coagulants such as aluminum sulfate and PAC are good coagulants, but further coagulation effects are required.

 The composition of the present invention has the ability to remove THMs and its precursors, and is not inferior to the ordinary S product in cohesion as described above, but rather, the mutual effect of coexistence of Al, Fe, and Mg is expected. . In other words, Floe increases due to the presence of Fe salts, which indicates the need for aggregation, and the specific gravity is large, so that the precipitation rate of Floe is increased and the water purification effect is improved.

 The presence of Mg further facilitates this trend.

 Metal removal effect

 Conventional inorganic coagulants have the ability to remove harmful metals, but depending on the type of wastewater and source water, these metals may remain in trace amounts.

 The composition of the present invention is not inferior to ordinary products in the ability to remove harmful metals. Rather, it is expected that the effects of these metals will be improved due to the improvement of the contact force due to the interaction of Al, Fe and Hg. In addition, the residual amounts of Al and Fe in the service water after coagulant treatment are very small and negligible.

Removal effect of THMs and forerunner substances

As mentioned above, ordinary flocculants are difficult to remove THHs and their deer substances. Tends to be difficult.

 These THMs are subject to regulation around the world, and their regulation values are less than 50 to 100 ppb.

 The present inventor has conducted tests to develop a flocculant capable of producing or effectively removing THHs and its precursors. An example of the test is as follows. Test conditions 1) .Sample sample-artificial Kaolin concentration 50 eg / 1

 Hu gen: ic Acid 5 Ra g / 1

 2) Adjust pH 7.0

 3). Water temperature 13.2

4). Concentration of added chlorine solution (chlorine «degree) 10 ng / J

5). Chlorine contact time 1 Hr

 6). Flocculant addition amount 215 ppm Test value table

試験結果第 1 表に表した如 く通常の凝集剤に比して Al，Fe系及び A1 Fe,Hg 系が THMs の残量が顕著に低いこ と を知る こ と が出来る。 本発明者等は A]，Fe系よ り A1，ト' e,Mg 系の THMs残量が顕著に低いので Mgの効果を確認するため下記の条件で Al，Feを固定 し Mgを活性させて 実験を実施し各組成物の濃度は酸化物合計量 8Ϊに したと ころ第 1 図の 如き結果を得た。

As shown in the test results in Table 1, it can be seen that the residual amount of THMs in the Al, Fe system and A1 Fe, Hg system is significantly lower than that of ordinary flocculants. The present inventors have found that the amount of THMs remaining in A1, Toe, and Mg systems is significantly lower than that of A] and Fe systems. Experiments were carried out to obtain the results shown in Fig. 1 when the concentration of each composition was adjusted to 8% of the total amount of oxides.

 As can be seen in Fig. 1, the amount of residual THMs was reduced as the amount of Hg increased, and Hg was found to be very effective.

 Thus, the present invention provides the composition of the present invention based on the surprising findings, and it is recognized that the removal of THMs is very effective. Economic effects

 The composition of the present invention has a good flocculating effect and at the same time has the ability to remove THMs and its precursors, and Fe, Mg-salts are relatively inexpensive in comparison with A] salts in terms of raw material price. In addition, minerals containing Al, Fe, and Mg can be used and their economic effects are great.

 BRIEF DESCRIPTION OF THE FIGURES

 Figure 1 is a graph showing the effect of removing THMs with the addition ratio of ME.

 [Example]

 Next, examples of the present invention will be presented.

 Example 1

 Experiments were performed on test samples corresponding to wastewater and tap water under the following conditions.

Implementation conditions 1) Test sample a) Artificial Kaolin portability 50 mg / 1 b) Hg, Cd, Cr, Pd concentration 1 rag / 1 c each) Huli ic Acid 5 mg / 1 2) Adjust PH 7.0

 3) Water temperature 15

 4) Chlorination solution Chlorine concentration 10 t / g

5) Chlorine contact time 1 hr

 6) Flocculant addition amount z86 ppB

7) Measurement method: Atomic absorption spectrophotometer

 THMs-one gas chromatography

 ECD detector

2. Measured value

 Table. 2

 (ND): Not detected

 As shown in Table 2, the composition of the present invention is the same as a flocculant compared to ordinary products.

 It shows equal or better effect, and the effect of removing THMs is also remarkable. Example 2

Korean蚝石_{(Verniculite):! A1 2 0} 3 10~12, Fe 2 0 3 11~13, MgO 6-7, the other 73-68 wtS) with mineral acid * management extracts (specific gravity 1 - 18 , Α1 ₂ 0 ₃ 2.1, Fe ₂ 0 ₃ 1.8, Experiments were performed under the same conditions as in Example 1 except that various salts were added to HgO 0.63 and other oxides 0.43 »).

 However, the added amount of various flocculants is 200 PP.

 Table 3

 (ND): Not detected

 As can be seen from Table 3, the composition of the present invention exhibits the same or better effect as a flocculant than conventional products even when the composition from mineral acid decomposed matter is mixed, and the effect of removing THMs is The same tendency was observed when using vermiculite hydrochloric acid or nitric acid extract. Example 3

Industrial wastewater containing heavy metals (PH 4, Cr 5 PPB, Ni 8 PP » containing) the extract of the present invention the composition obtained by reacting a mineral acid in vermiculite (atomic weight ratio of Al: Fe: Mg = l: l , 14: 0 · 34, oxides totaling 5 vt%) was added to 300 PP., Adjusted with _PH7 with lime oil and _treated according to the customary method. * _Purified solution ( _{PH7, Cr0.45, Ni0.67} ) ) Was obtained.

This can be recognized as a sufficient purifying effect as an inorganic flocculant. Example 4 Urban sewage <PH 6.5, SS 120ΡΡΠ, BOD 210 _PP B, coliforms (410X10 ^S / 100B1)> and vermiculite reactant (atomic ratio Al, Fe, Kg = 1: 0.27: 0.07 Total oxides 8.7 wt¾ ) Was added to 100 ΡΡ ·, ΡΗ was conditioned to 7.0, and treated as usual. As a result, purified solution <ΡΗ 7.0, SS 10.2, BOD 17 _PP «, coliform group (4X10 ² / 100B1)> was obtained. . It can be seen that this shows sufficient purification effect as an inorganic flocculant.

Claims

Claims 1. A water-soluble aluminum salt, a water-soluble iron salt, and a water-soluble magnesium salt contain Fe0.01-Mg001-1-2 with respect to AI1 in atomic weight ratio, and its oxide A Oa . Fe ₂ 0 _3, total 1 to 15 wt% der of HgO is, water heavy metals and preparative Riharo meth ting coagulant set Narubutsu that the precursor highly removed can.  1. Mineral acid decomposition of vermiculite (Ver.iculiee), which is a water-soluble aluminum salt, water-soluble iron salt and water-soluble magnesium salt mentioned in Paragraph 1 and contains aluminum, iron and magnesium. Water-soluble aluminum salt, water-soluble iron salt, and water-soluble magnesium salt were added to the product, and the ratio of Al, Fe, and Mg in item 1 was adjusted and adjusted to the same concentration as in item 1 for aggregation. Agent.