In the current and recent evaluation of organophosphorus pesticide wastewater treatment methods, the recommended method for treating organophosphorus pesticide wastewater is firstly Chemistry Activated Carbon adsorption, and the second is activated carbon sludge method. After treatment, the wastewater is diluted with a large amount of river water and discharged. Rivers have no effect on living things.
The activated carbon adsorption method is suitable for clear packaging containers, equipment and wastewater for washing the ground in the pesticide preparation factory, as well as wastewater for cleaning the pesticide packaging container on the farm.
According to the analysis of various organophosphorus wastewaters discharged from pesticide production plants in China, more than 95% of the organophosphorus compounds in wastewater are not pesticides, but their intermediates and degradation products at different stages.
The organophosphorus compound will be hydrolyzed during the placement process, and the phosphorus-sulfur bond in some of the dithiophosphates will be broken, so that the concentration of organic phosphorus in the adsorbed water is obviously increased, and the breakthrough point is advanced, but the adsorption of sulfur is the same as that of fresh wastewater. According to the analysis results, in the initial stage of adsorption, the organic matter adsorbed in the water is mainly methanol and monomethylamine, the ratio of BOD/COD is above 0.8, and the organic phosphorus gradually flows out from low to high according to the proportion of sulfur to phosphorus. Dimethoate and other compounds with large molecular weight and low polarity flow out when the activated carbon is nearly saturated.
Direct injection of Powder Activated Carbon into the biochemical treatment tank can also significantly improve the biochemical treatment effect of the dimethoate wastewater. When the dosage is 0.1% of the water inflow, the removal rate can be increased by about 20%. However, the waste water discharged per ton of dimethoate requires 0.8-1T activated carbon powder, and the cost is also large, and the recovery and regeneration method of carbon powder has not been solved, and there are still problems in industrial application. Although the cost of the treatment is problematic, in some special cases, such as when domestic water is contaminated with organophosphorus pesticides, temporary adsorption with activated carbon is effective and convenient.