Experimental Study And Mechanism Analysis On Printing And Dyeing Wastewater Treatment By Facultative Oxygen FMBR

The printing and dyeing wastewater has been recognized difficult dispose industrial wastewater at home and abroad which high content of organics,complex composition,deep chromaticity and great water quality variation.At present,even though has various of traditional technology and methods to treat the printing and dyeing wastewater,but all of them have kinds of disadvantages,such as occupying a large area,the high processing cost,harsh process conditions,the complex operation,being difficult for the water to reach the stable water-quality standards so that there is no appropriate technology widely accepted by environmental workers.The processing technology is facing a bigger challenge with the implementation of new environmental laws.Under the condition of considering the large engineering project construction,this paper used a set of 65 m3 facultative oxygen membrane bioreactor(FMBR)to deal with the wastewater in dyeing factory of Jiangxi province.The first phase of the experiment,the result showed that the system had great removal effect to all kinds of pollutants when the working time of reactor hydraulic(HRT)was up to 30 hours(h).The water quality met the requirement of the country "textile dyeing and finishing industrial water pollutant discharge standard"(GB4287-2012)in 2015.In order to optimize the process parameters,the best HRT for the system was researched firstly.The reactor worked for half a month under the condition that the HRT was adjusted to 20 h,18h and 15 h respectively.The result shows that only when the HRT conditions is 15 h,COD and chromaticity of reactor effluent can't meet the requirements of national direct emissions.In order to reduce the energy consumption of the experimental device further,on the premise of ensuring that water quality meets the standard,the DO of membrane area and facultative area ranged from 1.5-2.0mg/L and 0.5-1.0mg/L to 1.0-1.5mg/L and 0.5mg/L the following by controlling the air in the reactor.The results show that under the condition of the same HRT,reduce facultative area DO improve removal rate of COD and chroma in wastewater,the average removal rate increased by 1.0% and 0.3% respectively.But removal efficiency of NH3-N is greatly reduced,NH3-N in effluent was higher than the national emission standard.We determined the experiment developed under the best condition that HRT for 18 h,membrane area DO 1.5-2.0 mg/L,facultative area DO 0.5-1.0 mg/L.Under this condition,the average COD was 67.7%,averageremoval rate was 88.5%,average NH3-N was 7.1mg/L,average removal rate was81.7%,average chroma was 39 times,average removal rate was 90.6%.Interception of membrane was studied in COD and NH3-N and chroma removal effect,the results show that the membrane has good retention on the COD and colority,almost no interception of NH3-N.The removal effect of FMBR on pollutants was effected by operating conditions and factors such as HRT,DO,sludge loading,temperature,influent COD concentration,NH3-N concentration,pH,sludge concentration and so on.Meanwhile the change of sludge in the process of the reactor was analyzed.Finally,the related mechanism of FMBR has carried on the analysis discussion and the related theoretical basis was elaborated.