混凝工艺预处理中纤板废水的研究

Study on the pretreatment of MDF wastewater by coagulation

通过筛选,确定了聚合氯化铝(PAC)为混凝剂对中纤板废水进行混凝预处理。由于中纤板废水本身的浓度和脱稳性能随pH变化很大,使得混凝效果最佳的废水pH为5。当PAC投加量为2 g/L时,混凝工艺对废水中SS、COD和SCOD的去除率分别接近100%、50%和30%。通过分析PAC的混凝机理,认为PAC的最佳投加量主要与废水中SS有关而与COD关系不大。沉淀时间和助凝剂聚丙烯酰胺(PAM)的投加对混凝效果几乎没有影响,但可以有效加速絮体的沉降和减小污泥体积。研究结果为中纤板废水的混凝预处理提供了详细、可靠的理论依据。

PAC has been chosen as the suitable coagulant for pre-treating medium density fiberboard （MDF） waste- water by screening test. Since the concentration and destabilization properties of MDF wastewater itself varies greatly with its pH, the optimal pH during the coagulation process is 5. When the PAC dosage is 2 g/L, the removing rate of SS,COD and SCOD can almost reach 100% ,50% and 30% respectively. Through analyzing PAC coagulation mechanism, it can be considered that the optimal dosage of PAC is mainly related to SS concentration and might not be associated with COD concentration of the wastewater. Precipitation time and the addition of PAM have no influence on the effect of PAC coagulation but can accelerate the sedimentation of floc and reduce the floc volume. Therefore the research results provide detailed and reliable theoretic basis for the MDF wastewater pretreatment by coagulation.