Method for treating wastewater generated after preparing alcohol from cassavas as raw material

Abstract

The invention discloses a method for treating wastewater generated after preparing alcohol from cassavas as a raw material. The method comprises the following steps: (1) adding a primary flocculant according to an amount of 2-5kg / ton of wastewater into aerobic effluent which is discharged by virtue of active sludge treatment after preparation of alcohol, stirring uniformly, and standing for 10-40 minutes to obtain a sludge deposit and a supernatant; (2) adding a Fenton reagent into the supernatant, wherein the used amount of hydrogen peroxide is 0.8-2kg / ton of wastewater, the used amount of a ferrous salt is 0.6-3kg / ton of wastewater, and hydrogen peroxide is subjected to oxidative degradation reaction with substances in the supernatant; (3) adding an acid-alkali regulator to adjust the pH value to 6-9, and performing aeration treatment; and (4) adding a secondary flocculant into the waste solution after the aeration treatment according to a used amount of 2-10g / ton of wastewater to perform secondary sedimentation so as to ensure that residual impurities are deposited. After the wastewater is treated by the method disclosed by the invention, the COD (chemical oxygen demand) and SS (suspended substances) in discharged water are reduced to a very low level, the COD value is less than 300mg / L, the SS value is lower than 150mg / L, the color of the discharged water is light, and the foam in the discharged water is less, so that the wastewater reaches a standard of direct discharge.

Description

technical field [0001] The invention relates to a method for treating waste water after ethanol is prepared by using cassava as a raw material, and belongs to the technical field of waste water treatment after ethanol is prepared. Background technique [0002] Cassava is one of the three largest tuber crops in the world. It is rich in starch and is an important raw material for alcohol production. The process of using cassava as raw material to produce alcohol has become mature, and the residue after alcohol production has also been further utilized, but the waste liquid produced after alcohol production has not been effectively treated and directly discharged outside, which has a serious impact on the environment. The waste liquid has become the chief culprit of polluting the environment. If the alcohol waste liquid is not treated, there will be hidden dangers of damaging the environment. This problem has attracted the attention of alcohol manufacturers, and corresponding ...

AI Technical Summary

Problems solved by technology

The process of using cassava as raw material to produce alcohol has become mature, and the residue after alcohol production has also been further utilized, but the waste liquid produced after alcohol production has not been effectively treated and directly discharged outside, which has a serious impact on the environment. The waste liquid has become the chief culprit of polluting the environment

If the alcohol waste liquid is not treated, there will be hidden dangers of damaging the environment. This problem has attracted the attention of alcohol manufacturers, and corresponding measures have been taken. These measures are to directly contact the waste liquid with activated sludge. The organic matter in the waste liquid is degraded through the aerobic respiration of activated sludge. However, the concentration of TCOD and TSS (suspended solids) in the waste liquid after only such activated sludge treatment is still high and the color is deep. There is a lot of foam, it is difficult to use traditional advanced treatment processes such as membrane treatment and ion exchange treatment, and the cost is high, and it is not very good to ensure that the discharge is up to standard