微生物絮凝剂的制备及其对城市污水厂污泥的脱水

研究利用甘蔗渣作为廉价原材料制备微生物絮凝剂并探讨其对城市污泥的脱水性能。按0.5%最佳接种量接种,并利用发酵罐进行批式发酵培养,培养60 h后的发酵液具有最佳絮凝效果,投加量为5.0 mg/L时较优,污泥脱水率从75.60%提高到84.2%,污泥含水率从95.82%降至76.21%。此时絮凝剂粗产量为1.16 g/L。培养108 h后,发酵液仍具有显著的絮凝效果,能使污泥含水率维持在76.81%左右。补料发酵实验表明,恒pH培养会抑制微生物分泌絮凝剂,最佳絮凝效果为72 h的发酵液,投加量5.0 mg/L,污泥含水率降至76.47%。通过补料以及不控制pH后,发酵液絮凝效果迅速上升,投加不同量的发酵液使污泥的含水率保持在76.22%~75.60%之间。综合来说,补料在能减少原料浪费的同时也可以有效地提高絮凝剂的絮凝效果。

Microbial flocculant preperation and its application in dewatering of sewage treatment plant sludge

Bioflocculant was produced by using sugarcane bagasse as a cheap raw material to culture Aspergillus Aspergillus and its ability to remove water from sewage sludge was studied. The results showed that with the optimum inoculation volume of 0.5%, the lowest moisture content of sludge achieved after 60 h fermentation through batch culture. At the best bioflocculant dosage of 5.0 mg/L, the dewatering rate of sludge increased from 75.6% to 84.2%, and its moisture content decreased from 95.82% to 76.21%, with crude bioflocculant yield of 1.16 g/L. The sludge still kept lower moisture content, remaining about 76.81% after 108 h batch fementation. The constant pH in the process of fementation would inhibit A. sojae to secrete bioflocculant during fed-batch fementation. Under this condition, the sludge moisture rate was 76.47% after culturing A. sojae for 72 h at the best dosage of 5.0 mg/L. The flocculating effect of fermention liquid rose rapidly after feeding new culture medium and stopping pH control. The sludge moisture rates under different bioflocculant dosages were kept between 76.22%~75.60%. Generally speaking, feeding new culture could both decrease the waste of raw material and improve the flocculating rate of flocculant efficiently.