Study And Application On Treatment Of Pesticide Wastewater By Combined Process Of Chemical Phosphorus Removal+fenton Oxidation+ABR+two-stage A/O

China is a large agricultural country,and the annual demand for pesticides is also gradually increasing.At present,there are countless domestic pesticides production enterprises,and the amount of pesticides wastewater discharged in the process of pesticides production is also a considerable figure.It will bring serious harm to the ecological environment if not be treated.The research object of this paper is pesticides wastewater with the characteristics of high concentration,high toxicity,poor biodegradability and difficult treatment.The research site of this paper is located in a pesticide production company in Jiang Xi,which specialized products intermediates of pesticide.The pesticide production company mainly has two production workshops.The production wastewater in one workshop has the characteristics of high concentration of COD_Cr,up to 30000 mg/L,and the daily water volume is about 150 tons;The wastewater produced by another workshop has the characteristics of high phosphate,high ammonia nitrogen and high salinity.The phosphate content is as high as 10000 mg/L,the ammonia nitrogen is about 150 mg/L and the salinity is 5000 mg/L.The company plans to expand a new factory and increase production scale.The main purpose of this study is to take the original pesticide production wastewater as the research object,selecet feasible and efficient treatment processes,and determine the optimal operation conditions of each process.After the completion of the project,its daily detection and commissioning shall be carried out to ensure that the effluent can meet the discharged standard.Through small-scale experiments,the process of"chemical phosphorus removal+Fenton oxidation+ABR+two-stage A/O"was determined for wastewater treatment.The main conclusions of this research are as follows:（1）The optimum operating conditions of Chemical phosphorus removal are as follows:the initial p H of wastewater is 11,the input amount of Ca（OH）₂ is 55 g/L,and the reaction time is 30 minutes.Under these conditions,the removal rate of TP can reach more than 95%.（2）The optimum operating conditions of Fenton oxidation are as follows:the initial p H of wastewater is 3,the input amount of H₂O₂ is 20 ml/L,the input amount of Fe SO₄·7H₂O is 18.5 g/L,and the reaction time is 2 hours.Under these conditions,the removal rate of COD_Cr is about 30%.（3）After commissioning and operation,the removal rate of COD_Crby ABR pool is stable between 30%～40%,the removal rate of COD_Crin the two-stage A/O pool is more than 90%and the removal rate of NH₃-N is about 80%.The overall operation of the combined process is stable,and the effluent can meet the discharged standard.（4）Through calculation,the comprehensive treatment cost of the pesticide wastewater is 19.3 yuan/ton.