Study On Treatment Technology Of Organophosphorus Pesticide Wastewater And Design Of Its Control System

Organic phosphorus pesticide wastewater is a kind of refractory wastewater,which has characteristic of high organic,high phosphorus,high salt,and high ammonia nitrogen "four high".Organophosphorus pesticide chemical structure is complex,completely using the traditional biological treatment method cannot reach the water requirements.In order to solve the organic phosphorus pesticide wastewater treatment problems,in this paper,the processing method of diazinon pesticide wastewater of a pesticide factory in Wenzhou was compared.The advanced oxidation technology(AOP)was studied on laboratory and field pilot study was carried out.A set of automatic control system was designed for the process.Advanced oxidation pretreatment is a common method for the treatment of refractory wastewater,which can interrupt the chemical structure of organophosphorus pesticides and degrade organic phosphorus pesticide wastewater.Through the investigation and study,it is found that all the advanced oxidation methods which can degrade organophosphorus pesticides,iron-carbon microelectrolysis Fenton process is a very promising treatment method.It not just is a simple joint process,but a great combination of the two reaction mechanisms.It is a feasible method for pretreatment of diazinon pesticide wastewater.The ferrous carbon micro-electrolysis-Fenton-coagulation sedimentation process was used to study the wastewater of the diazinon industrial wastewater.The influence factors of each link are studied.Found,the optimal treatment condition of iron-carbon micro electrolysis was iron-carbon dosage 262 g/L,pH = 3,reaction time 120 min.The optimal treatment condition of Fenton reaction was 30% H2O2 15 mL,FeSO4 18 g,reaction time 120 min,pH = 3.The optimal treatment conditions of coagulation sedimentation was PAC 1000 mL,pH = 8.The results showed that the removal rates of COD of iron-carbon micro electrolysis,Fenton reaction,coagulation sedimentation were 33.17%,64.91% and 12.28%,respectively,and the removal rates of ammonia nitrogen were 30.67%,66.95% and 9.82%,respectively,under the optimum conditions.A pilot study was carried out on the treatment of diazinon wastewater by "two-stage ferricFenton-coagulation-AAO-Fenton-coagulation-activated carbon adsorption" process.After the pilot system in the trial and sludge acclimation to achieve stable operation.When the COD concentration of inlet wastewater was 20845 mg/L.The COD removal rate of the two-stage advanced oxidation system,biochemical treatment AAO system and post-treatment tertiary oxidation-activated carbon adsorption system reached 89.2%,91.9% and 91.8%,respectively.The concentration of COD of outlet was between 8 and 80 mg/L,which reached the discharge standard of pesticide wastewater.On the other hand,although the "two-stage iron carbon-Fenton-coagulation sedimentation-AAO-Fenton-coagulation sedimentation-activated carbon adsorption" process can be a diazinon wastewater treatment.Each unit process must be controlled in practical engineering application.The control method is that the iron-carbon micro-electrolysis,the coagulation sedimentation,the activated carbon adsorption and the Fenton reaction take the control of the dosage of the medicine according to the amount of the influent and the method of controlling the p H value within a certain range.In particular,Fenton's dosage of H2O2 because of the dosing method will affect the dosage of FeSO4 and treatment effect,FeSO4 dosing to take a one-time a large number of dosing methods,H2O2 to take a slow way to dose.The sludge back flow control was used to control anaerobic tank.The control method of anoxic tank is the control of the reflux of the nitrification solution and the control of the redox potential(ORP).Aerobic pool as a result of the use of plug-flow contact oxidation tank,need take the front and back point's method to control the DO constant value constant.