MBR Treatment Variation And Control Method Of Dyeing Process Wastewater EPS

As one of the reasons leading to membrane fouling in MBR, EPS(extracellular polymeric substance) has become a focus for many study on how to control membrane fouling. However there are few studies on the production of EPS when use MBR to treat with dyeing wastewater. So this study was conducted when treat dyeing wastewater with MBR, and mainly focus on the following aspects like:the method for extracting EPS; the relationship between the production of EPS and MBR operating conditions; the useful method to control the amount of EPS. Through the study we can get the following conclusions:(1) The amount of EPS extracted by pulverous ion exchange resin is22%-64%larger than the amount extracted by granular ion exchange resin. The best pH value for extracting EPS is9. The most appropriate dose of pulverous ion exchange is40g/(g污泥) with exchanging time of3hours. And the measurement of EPS indicates that activated sludge treating with dyeing wastewater produces less total EPS and more EPS polysaccharides than activated sludge treating with domestic sewage.(2) When increase the aeration rate, the scouring force of water and the activity of sludge enhanced. EPS proteins contribute more to membrane fouling than EPS polysaccharides. And soluble EPS contributes more to membrane fouling than bonded EPS. When setting aeration rate as0.08m3/(L-h), the concentration of soluble EPS can reach the lowest level, and the strongest turbulence around membrane can scouring membrane. So the aeration rate of0.08m3/(L·h) is the best to prevent membrane fouling. Besides, when the sludge load is1.03kgCOD/(m3·d), the amount of EPS produced equals to the amount degradated, hence the concentration of soluble EPS reached the lowest level. So the sludge load of1.03kgCOD/(m3·d)is best to prevent membrane fouling.(3) When input60mg/L of FeCl3, the concentration of soluble EPS can be decreased from41mg/L to31mg/L.60mg/L is the best dose for controlling EPS, and more FeCl3can cause autolysis of the cell of microorganisms so that more EPS can be produced. PAC can not only adsorb EPS and dye but also form a strong scouring force to the surface of membrane. More amout of PAC will be better for controlling EPS and membrane fouling. However, in order to save the cost, the dose of PAC can be set as15g/L which has already been effective to control membrane fouling.