Abstract:

Based on the operation of the hydrocyclone which is employed to treat 200 t/h excess sludge in a wastewater treatment plant (WWTP) in Sichuan Province, the effects of hydrocyclone split ratio (F) on the morphology, settleability, concentration, composition and the release of carbon source of the underflow and overflow sludge are compared, and the feasibility of using the substance released from sludge treated by hydrocyclone as the carbon source for denitrification process was explored. The results show that after the sludge is treated by the cyclone, the structure of the underflow sludge becomes dense; the overflow sludge becomes loose. Under different conditions of split ratio, the ratios of proteins to polysaccharides (PN/PS) of both the underflow and overflow sludge increased, the values of sludge volume index (SVI) of the underflow sludge was lower than those of the inlet sludge. However, the SVI of the overflow sludge increased when F was less than 30%, and decreased when F was greater than or equal to 30%. The carbon source release of sludge varied with different values of split ratio, the carbon source release of the underflow sludge reached the maximum when F was equal to 30%. With this split ratio, the denitrification rate of the underflow sludge was higher than that of the inlet and overflow sludge. The denitrification rate of the carbon source released by the underflow sludge was 0.81 mg/(g·h), which was equivalent to that of the analytical grade sodium acetate (0.82 mg/(g·h)), higher than that of the industrial grade sodium acetate (0.64 mg/(g·h)) and the microbial compound carbon source (0.66 mg/(g·h)) which are commonly used in WWTP. The SCOD and protein discharged from the sludge treated by hydrocyclone can supplement the carbon source for denitrification, reduce the addition of external carbon source, and provide technical references for the upgrading of WWTP.

Key words: hydrocyclone, wastewater treatment plant, waste water, separation, recovery, carbon source, denitrification

摘要：

基于四川省某城市污水厂处理200 t/h剩余污泥的旋流器运行情况，比较了旋流器分流比（F）对底流和溢流污泥的形貌、污泥沉降性、污泥浓度、成分变化和碳源释放的影响，探究了污泥旋流释放物质作为反硝化碳源的可行性。结果表明：污泥经过旋流器处理后，底流污泥结构变得密实；溢流污泥松散。在不同分流比条件下，底流和溢流污泥蛋白质和多糖比值（PN/PS）均增大，底流污泥体积指数（SVI）较进口均降低。但是，溢流污泥在F<30%时SVI增大，在F≥30%时SVI降低。污泥的释碳情况随分流比不同而有变化，当F=30%时，底流污泥碳源释放量达到最大。在此分流比条件下，底流污泥反硝化速率较进口污泥和溢流污泥高，底流污泥旋流释放的碳源反硝化速率达到0.81 mg/(g·h)，与分析级乙酸钠碳源相当（0.82 mg/(g·h)），高于污水厂常用的工业级乙酸钠（0.64 mg/(g·h)）和微生物复合碳源（0.66 mg/(g·h)）。污泥旋流释放的SCOD和蛋白质可补充反硝化碳源，减少外碳源投加，为污水处理厂升级改造提供技术借鉴。

关键词: 旋流器, 城市污水厂, 废水, 分离, 回收, 碳源, 反硝化