SU916441A1 - Method for purifying effluents from arsenic - Google Patents

Description

The invention relates to the treatment of wastewater from arsenic, in particular to biological treatment and can be used to clean industrial wastewater from arsenic.

Known phosphate 'method for purifying wastewater from ⁵ arsenic ions with chemicals by which sewage is reached before the maximum permissible concentration (MPC) to form a substantially insoluble calcium phosphate ^10-arsenic complex. This method can be effectively used only in the presence of the oxidized form of arsenic Αδ (V).

Since industrial effluents usually contain arsenic in the trivalent form, the solution is first oxidized with pyrolusite (LLO ^) before purification, and then precipitated into an insoluble complex using milk of lime and phosphates 111.

The disadvantage of this method is that the oxidation of arsenic (III)

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With the help of pyrolusite, a preliminary, transverse dilution of arsenic wastewater is required to a concentration of 150,200 kg / l Az (W) at its initial concentration in the effluent of 1.0-1.5 g / l A $ (W), i.e. This method does not allow purification of wastewater to the required standards in the case of high arsenic ion content. In addition., Pyrolusite oxidative columns have to be periodically regenerated with sulfuric acid, since as they are used, pyrolusite loses its oxidizing properties, which requires additional operating costs.

The closest in technical essence and the achieved result to the proposed is a method of biological treatment of wastewater from arsenic iron bacteria Oslacia,

ΙαρΙοίΚτίχ сга55с1, Са ^ обебаа £ eggi <ξϊηβ <5 with simultaneous introduction of metallic iron and reducing agent in the form of sodium sulphide.

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The known method allows you to clean up drains containing up to 4 mg / l of arsenic after 4 daily contact of microorganisms with a certain volume of water at a temperature of 18-22 ° C [2]. five

The role of microorganisms in this method is indirect, since the method is based on oxidation by iron bacteria Fe (P) to Fe (III) and chemical precipitation of arsenic by the latter. ^ten

When the arsenic content is> 4 mg / l, the known method does not provide the degree of purification necessary before the MPC.

The purpose of the invention is to increase the degree of purification. ¹⁵

This goal is achieved by the fact that in the method of sewage treatment of arsenic (III) by oxidation to arsenic (Y), followed by treatment with phosphates and milk of lime, oxidation is carried out by microorganisms Reyeiotopaz ρυΐΐβα υ AVsIsh ^ eoez. eu ^ gorAyuv. ·

Microorganisms are aerobic, gram-negative, non-digestible bacilli that can use a wide range of organic substances as a carbon source. Therefore, mixing industrial wastewater with a small amount of domestic wastewater effluents, yeast production effluents, breweries and other wastewaters containing organic substances has a stimulating effect on times. vitie microorganisms as they MO ₃₅ Gut used as a source of energy and nutrition * A variety of body "nical connection. We should not be afraid that the microflora of domestic wastewater can suppress the development of bacteria from bacteria, since the usual saprophytic microflora is not resistant to high concentrations of arsenic and quickly dies.

The distinctive property of ве ₄₅ ρυΙΑάα is tolerance.

To low temperatures and the ability to develop in the range of 3-3 ° C. Bacteria culture AU wasp in

This can actively develop ₅ θ and oxidize 'arsenic in a wide range of pH from 6 to 10.5. The microorganisms capable of oxidizing arsenic contained in the solution at a concentration of 1.5-3.0 g / l B (III) at pH 7-9 without the addition of _PA-55 alignment.

With the passage of the solution through a layer of microorganisms adsorbed on

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solid carrier, trivalent arsenic is completely oxidized to pentavalent and then precipitated into a practically insoluble precipitate with phosphates and calcium.

For the purification of very acidic effluents (pH 1-3) with the help of microorganisms, preliminary alkalinization of water in the pH range 7-9 is required, but this does not affect the economics of the process, since to obtain solid solutions of arsenic, it is always necessary to further alkalify the effluent to pH 11- 12. Therefore, after passing the solution through a column with microorganisms, you only need to add the missing amount of alkali to a pH of 11-12.

Such an oxidative column with arsenic-acidifying microorganisms can function continuously with the same activity, since the adsorbed cells multiply well and do not require additional manipulations for their regeneration.

Thus, the cleaning process can be carried out both continuously and periodically in the temperature range from 3 to 30 ° C.

Example!. In 9 rocking flasks with medium and arsenic, add mont-morillonite clay, on which microorganisms are adsorbed. Then in 3 flasks add the culture of arsenic acid bacteria P5iiyotogav 35iIsYas1, strain 18, in 3 flasks - culture Ayso δ'ΐς, εηεβ eo! hump strain 280 and in 3 the following flasks add a mixture of cultures Rb.RIISS! strain 18 and A. greengrass, I5, strain 280. Thus, it was found that the rate of arsenic oxidation with a mixture of cultures is two times higher than that of individual strains with the same biomass of microorganisms.

Example 2. Microorganisms RB. For strain 18 and A. ekkorbye, strain 280 is adsorbed onto montmorillite clay, foam rubber or expanded clay. Then the microorganisms with the adsorbent are placed in an oxidizing column with a working volume of 7 liters.

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Sewage water containing 1.5-2.0 g / l AB (W) at pH 7-8 is passed through the column at a speed of 2.5 l / day. To intensify the process, 15 g of organic matter in the form of beet pulp is added to the column. The solution after passing through the column contains fully oxidized arsenic (pentavalent),

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which is then precipitated with phosphates and lime milk.

The column worked continuously for 30 days at a constant speed and, at the same time, the vital activity of microorganisms 5 was not inhibited.

The advantage of this method is the ability to clean undiluted wastewater containing up to 1500-2000 mg / l of arsenic. ten

Claims (1)

Claim. Method of wastewater treatment from mice - 15 shyak (Ø) by oxidation to arsenic (U) followed by treatment with phosphates and milk of lime, which is attributed to the fact that, in order to increase the degree of purification, oxidation is carried out by microorganisms Rzbibotz ηαε ρυΐΐοΐεΐ. and A8SovAe $ yp05 vi £ horn.