There are a wide variety of pesticides and the water quality of wastewater is complex. Its main characteristics are:
1) The pollutant concentration is high, and the COD can reach tens of thousands of mg/L;
2) It is highly toxic. In addition to pesticides and intermediates, the wastewater also contains toxic substances such as phenol, arsenic, mercury, and many substances that are difficult to degrade by organisms;
3) It has a foul odor and is irritating to the human respiratory tract and mucous membranes;
4) The water quality and quantity are unstable, and the seasonal changes are large.
How to deal with formaldehyde-containing pesticide wastewater?
Formaldehyde is a toxic, mutagenic and carcinogenic organic substance. Pesticide wastewater containing formaldehyde is one of the highly toxic and difficult-to-treat chemical wastewaters.
Is there a technology or solution that can not only effectively help pesticide companies deal with formaldehyde-containing pesticide wastewater, but also scientifically and reasonably control investment and operating costs?
(1) When the formaldehyde concentration is above 5000 mg/L, the formaldehyde is recovered by steam stripping;
(2) When the formaldehyde concentration is 1000-10000 mg/L, the lime condensation method can be used for pretreatment, and the formaldehyde in the wastewater is converted into substances with lower biological toxicity, and then treated by the microorganism method.
(3) When the formaldehyde concentration is within 2000 mg/L, the sodium sulfite reduction method can be used for pretreatment, and the reduction of sodium sulfite can be used to reduce aldehydes to alcohols, reduce the toxicity of wastewater, and improve the biodegradability, and then use the microbial method for treatment. The method has mild reaction conditions, high efficiency, and no secondary pollution. The disadvantage is that the operation cost is relatively high.
(4) For pesticide wastewater with a formaldehyde concentration of less than 1000 mg/L, it is recommended to use the microbial method. The “LBQ compound microbial flora” used in this method can withstand the toxicity of 1000 mg/L formaldehyde-containing wastewater, and at the same time effectively degrade various organic substances in the wastewater. pollutants, ensure that the formaldehyde concentration in the effluent is below 0.1 mg/L. The main advantages of biological method are good effect and low cost.
(5) For pesticide wastewater with low formaldehyde concentration, the “AOP oxidation” technology can be preferentially used, so that the formaldehyde concentration in the effluent is less than 0.5 mg/L.