臭氧作用改善膜-生物反应器混合液膜过滤性

提出了利用臭氧作为调控膜-生物反应器中活性污泥混合液的方法,采用小膜过滤装置测定臭氧作用后混合液的膜过滤性变化,并通过测定混合液MLSS、胞外多聚物(EPS)含量、絮体粒径、上清液胶体有机物浓度、黏度的变化,探讨了混合液膜过滤性变化的原因.结果表明,当臭氧投加量低于8.5mg/L条件下,混合液的膜过滤性得到改善.臭氧对混合液的主要作用是氧化污泥絮体表面的部分EPS,使污泥絮体表面性质发生改变,引起絮体再絮凝,絮体粒径增大,上清液胶体有机物浓度和黏度减少,从而改善混合液的膜过滤性质.

Improvement of membrane filterability of mixed liquor in membrane bioreactor by ozonation

Ozone was used as a method for modifying the characteristics of the activated sludge mixed liquor in the membrane bioreactor. A mini-membrane filtering instrument was adopted to determine the change of membrane filterability of the mixed liquor after ozone action and through determination of MLSS, extra-cellular polymeric substance (EPS) content, floc size, supernatant colloidal organic concentration and viscosity, the cause of the change of membrane filterability of the mixed liquor was inquired into. That membrane filterability of the mixed liquor was improved when the adding amount of ozone was less than 8.5mg/L. The main action of ozone on mixed liquor was oxidizing the surface part EPS of the sludge flocs, which changed the surface property of the sludge flocs, inducing re-flocculation of the flocs, increase of floc size and decrease of supernatant colloidal organic and viscosity, so the membrane filterability of mixed liquor was improved.