Zhejiang Chemical Co., Ltd. Pesticide Production Wastewater Treatment Project

A company in Zhejiang uses a chemical synthesis process to produce the herbicide Dicamba. The production process is complex, and the wastewater pollutants mainly include organic compounds such as phenols, salicylic acid, xylene, alcohols, esters, as well as salts such as sodium and potassium. The daily sewage volume is 80 tons.

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案例詳情

A company in Zhejiang uses a chemical synthesis process to produce the herbicide Dicamba. The production process is complex, and the wastewater pollutants mainly include organic compounds such as phenols, salicylic acid, xylene, alcohols, esters, as well as salts such as sodium and potassium. The daily sewage volume is 80 tons.

 

Water quality indicators CODCr Phenols saltness
Inflow value (mg/L) ≤6000 ≤300 ≤15000
Effluent value ≤500 ≤5 -

 

Based on the characteristics of the company's wastewater, macroporous resin is first used to adsorb phenols, and the phenols in the wastewater are recovered through alkaline backwashing to achieve resource utilization of the wastewater; In addition, due to the use of a large amount of heterocyclic and benzene ring substances in the production process, as well as the presence of sodium sulfate, potassium salt, etc., the salt content of the wastewater is high, exceeding the range that ordinary biochemical process microorganisms can withstand. A salt tolerant bacterial biochemical combination is used to treat the wastewater after resin adsorption, further reducing the COD and residual phenols in the wastewater. After biochemical treatment, the wastewater is treated by flocculation and sedimentation, and then discharged up to standard.
After adjusting the water volume and quality of the regulating pool, the phenolic wastewater is first pumped to the macroporous resin adsorption column through a corrosion-resistant pump. A precision filter is installed in front of the adsorption column to remove suspended solids in the wastewater to prevent blockage of the adsorption column;, The adsorption resin has the characteristics of good adsorption effect, easy desorption and regeneration, stable performance, wide applicability, good practicality, and comprehensive utilization. After being adsorbed by macroporous adsorption resin, wastewater can significantly remove phenols and organic matter, reducing the burden of subsequent biochemical treatment. After adsorption saturation, the macroporous resin needs to be regularly regenerated with NaOH solution (about 5%) to recover the phenol sodium solution. The recovered phenol sodium solution can be applied to production.
The salt content of the wastewater after phenol removal is around 2% after neutralization with waste alkali. This project adopts functional bacterial hydrolysis and contact oxidation treatment technology that can withstand high salinity. The hydrolysis tank is equipped with a special filling material for salt tolerant bacteria, and a reflux pump is installed for forced circulation; Special combination fillers are hung in the contact oxidation tank, and efficient salt tolerant bacteria are added to the hydrolysis tank and contact oxidation tank. Efficient salt tolerant bacteria are heterotrophic bacteria that can directly treat high salt organic wastewater, with amino acids, small molecule fatty acids, sugars, and proteins as nutrients. After biochemical treatment by salt tolerant bacteria, the organic matter in the wastewater is significantly reduced. After biochemical treatment, the wastewater enters the flocculation and sedimentation process section to further ensure compliance with discharge standards.