Method for treating wastewater with high sulfate and high COD

Abstract

The invention discloses a method for treating the high sulfate and high COD wastewater, including the treatment step of one-step SO42- removal combined with one step anaerobic treatment, the treatmentstep adopts aluminum source compound and calcium source compound as the treatment reagent, adds the reagent to the high sulfate and high COD wastewater to be treated, controls the reaction in the wastewater with pH between 9.5-10.5 to generate the ettringite precipitation, makes the concentration of the SO42- in the wastewater reduced to2500-4500 mg / L, then dilutes and dispenses the clear liquidof the wastewater post sedimentation to the range with COD between 5000-10000mg / L and SO42- below 1000mg / L, and conveys the clear liquid to the anaerobic reactor for further anaerobic treatment. The treatment method obtained solves the problem of the disadvantage brought to the subsequent anaerobic treatment post the SO42- removal from the wastewater by CaSO4 or BaSO4 precipitation approach in theexisting technology, which enables the anaerobic treatment system to run efficiently and stably in the high sulphate wastewater treatment application, meanwhile, the treatment method has significantly optimized the processing technology, making the operation more simple and convenient and the treatment effect more economical and environment-friendly.

Description

technical field [0001] The invention relates to the technical field of environmental protection, in particular to a method for treating waste water with high sulfate and high COD. Background technique [0002] Chemical and pharmaceutical, food processing, papermaking, mining and other industries will produce a certain amount of organic wastewater with high sulfate content, such as antibiotic wastewater, monosodium glutamate wastewater, sulfate process papermaking wastewater, acid mine wastewater, etc.; sulfate wastewater entering the surface will not only cause water pollution Acidification will affect the growth of aquatic organisms; it will pollute the soil, cause soil compaction, and destroy the ecological balance of the soil; in addition, the H produced by sulfate reduction 2 S and other malodorous gases escape from the water body and cause air pollution; therefore, sulfate wastewater needs to be treated before it can be discharged. [0003] The treatment of sulfate was...

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Problems solved by technology

[0004] (1), using biological method, using sulfate-reducing bacteria to reduce SO 4 2- Revert to S 2- , using nitrogen or desulfurized biogas for blow-off treatment, the gas blown out of the reactor is desulfurized and then recycled for blow-off, and the sulfide in the desulfurization reactor wastewater is discharged for iron salt precipitation treatment, but because hydrogen sulfide is easy Flammable, explosive and poisonous substances have high requirements on the safety of the operating environment and cause great physical harm to on-site operators. Most enterprises do not accept this process, and when COD(mg / L) / SO 4 2- (mg / L)<2 seriously affects the sulfate reduction efficiency;

[0005] (2), add lime to generate CaSO 4 Precipitation, suitable for the treatment of acidic wastewater, but due to CaSO 4 Slightly soluble, the sediment is not easy to filter, and when it enters the anaerobic treatment system, it is easy to accumulate and form hard scale at the bottom of the reactor, which affects the water distribution effect of the reactor and the mixing effect of wastewater and anaerobic sludge. On the other hand, anaerobic reaction It is troublesome to overhaul and clean up the device, and the safety requirements are high;

[0006] (3), add barium salt to produce BaSO 4 Precipitation, the precipitation effect is good, the removal rate is high, but the barium salt is toxic, and the operating cost is high, the sludge production is large, and it is easy to cause secondary pollution;

[0007] (4), using two-stage anaerobic treatment process, the anaerobic reaction of the first stage is mainly the hydrolytic acidification stage, and the anaerobic reaction stage of the second stage is mainly the methanogenic stage. This process reduces the S 2- and sulfate-reducing bacteria on anaerobic production, but most of the S produced by the system 2- Still exists in the sewage, the effect is limited;

[0008] When the above methods are used to deal with acidic high sulfate organic wastewater, there are some shortcomings and deficiencies, resulting in the inability to effectively and reliably eliminate SO 4 2- The impact on the anaerobic treatment system limits the anaerobic treatment of high-concentration sulfate organic wastewater

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