次氯酸钠控制城市污水处理厂微丝菌污泥膨胀

Control of Sludge Bulking Caused by Microthrix parvicella Using Sodium Hypochlorite

针对由微丝菌引起的城市污水处理厂营养物去除系统的活性污泥膨胀,采用投加次氯酸钠进行氧化控制,探讨不同剂量下次氯酸钠对微丝菌的杀灭效果、活性污泥沉降性能的改善以及对功能微生物(聚磷菌)的损伤和恢复。结果表明,次氯酸钠使裸露于絮体外的菌丝断裂,污泥容积指数减小;随着非丝状菌的增殖和剩余污泥排出,活性污泥沉降性能进一步改善;次氯酸钠的投加量越高,对聚磷菌吸磷和释磷速率影响越大,但聚磷菌释磷速率减小的幅度小于吸磷速率。最佳投药量为5.3 g Cl/kg MLSS,此时SVI由未投加次氯酸钠时的202 m L/g降至134 m L/g,最大释磷速率和最大吸磷速率同比分别降低了11%和40%。可见,投加次氯酸钠能有效控制微丝菌引起的污泥膨胀。

Sludge bulking caused by Microthrix parvicella in the municipal wastewater treatment plant was cured by dosing sodium hypochlorite. The improvement of the settlement properties of activated sludge and the damage and recovery of the functional microorganism( PAOs) were investigated with different dosages. The results showed that the sodium hypochlorite could kill Microthrix parvicella and cut them into pieces,so that the settlement performance of activated sludge was improved with the proliferation of non-filamentous bacteria and the discharge of residual sludge. The higher the dosage of sodium hypochlorite was employed,the greater damage on the phosphorus release rate and phosphorus uptake rate was observed. However,the effect on phosphorus uptake rate of PAOs was greater than that on the phosphorus release rate. The sludge SVI was reduced from 202 m L/g to 134 m L/g with optimal dosage of 5. 3 g Cl/kg MLSS of sodium hypochlorite. At the same time,percentages of the maximum specific phosphorus release rate and the maximum specific phosphorus uptake rate were reduced by 11% and 40% respectively. Sodium hypochlorite can be used to control the sludge bulking caused by Microthrix parvicella.