Application On The Treatment Process Of The Wastewater From The Organic Silicon Intermediate Production

A chemical company mainly produces tetramethyl divinyyl disiloxane,methyl hydrogen-containing silicone oil and N,N-carbonyl diimidazole,which will produce high-concentration complex wastewater in the production process,the wastewater contains a certain amount of silicone oil,and It has the characteristics of high NaCl,high COD,and poor biodegradability.It is necessary to design a sewage treatment plan that is highly feasible and economical in engineering.After a small trial experiment,it is finally determined to use "air floatation+three-effect evaporation+Fe-C "Micro electrolysis+enton oxidation+UASB+A/O+BIOFOR biological filter" combined process to treat the integrated wastewater:In view of the characteristics of high oil concentration,high salt concentration and high COD concentration in wastewater,the pretreatment of "air floatation+three-effect evaporation+Fe-C micro-electrolysis+Fenton oxidation" is used.Degreasing and desalting waste water to improve the biodegradability of waste water.The best reaction conditions were obtained through the combined experiment of Fe-C micro-electrolysis and Fenton oxidation:the dosage of Fe powder was 8g/L,the dosage of C powder was 8g/L,and the dosage of FeSO4 was 3.0g/L,30%The dosage of H2O2 was 5ml/L,the reaction pH was 3,and the reaction time was 2h.COD removal rate can reach 40%,NH3-N removal rate can reach 20%.For the characteristics of high oil concentration,high salt concentration,high COD concentration,and high turbidity in wastewater,pretreatment of "air floatation+three-effect evaporation+Fe-C micro-electrolysis+Fenton oxidation" is required.After oil separation and air floatation pretreatment of wastewater,COD was reduced from 44560mg/L to 30350mg/L,and the removal rate was about 30%;after three-effect evaporation pretreatment of wastewater,the salt removal rate was as high as 99%or more.Part of the COD can be removed;the wastewater is subjected to the combined treatment of Fe-C micro-electrolysis and Fenton oxidation process,and the best reaction conditions are obtained through experiments:the dosage of Fe powder is 8g/L,the dosage of C powder is 8g/L,FeSO4 The dosage is 3.0g/L,the dosage of 30%H2O2 is 5ml/L,the reaction pH is 3,and the reaction time is 2h.The removal rate of COD is about 40%,and the removal rate of NH3-N is up to 20%.After the pretreatment process of the integrated wastewater,the biodegradability of the wastewater is significantly improved,and it enters the "UASB+ A/O+BIOFOR" biochemical treatment section.Through research on the feasibility,design,experiment,start-up and commissioning and operation data of this project,the results show that:(1)The stable operation of the UASB anaerobic tank,the inlet water temperature is controlled at 25?35?,and the pH value is controlled at 6.8?7.2,the volume load is controlled within the range of 2-5kgCOD(m3/d),the effluent COD is about 900mg/L,and the removal rate is 80?90%;(2)The stable operation of the A/O pool,controlling the dissolved oxygen at 2?4mg/L,pH value controlled at 7.0-8.0,the final removal rate of COD and NH3-N are 80%and 70%respectively;(3)During the stable operation of BIOFOR biological filter,it needs to be backwashed at 1 week 1 time,ensure that the effluent meets the standard.The removal rate of COD and NH3-N in the final biological filter is 70%and 60%,respectively.The project's comprehensive wastewater water quality COD is about 45000mg/L and NH3-N is about 480mg/L.After 4 months of commissioning and operation,the removal rate of COD by this set of sewage treatment system is stable at over 99%,and the effluent COD 100mg/L or less;the removal rate of NH3-N is about 98%,and NH3-N is less than 15mg/L,which meets the first-level standard in Table 4 of the Comprehensive Wastewater Discharge Standard(GB8978-1996).The "air floatation+three-effect evaporation+Fe-C micro-electrolysis+Fenton oxidation+UASB+A/O+BIOFOR biological filter" combined process is used to treat such complex wastewater,and the effluent quality is stable.This set of technology is mature and has good operation effect.It provides a reference example for the design of wastewater treatment in the silicone industry.After the stable operation of the sewage station,the treatment cost of each ton of wastewater is 90.4 yuan/ton under the premise of only considering the cost of chemicals,steam and electricity consumption.The industrial production wastewater treatment design provides reference examples.