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Qu F.,Harbin Institute of Technology | Liang H.,Harbin Institute of Technology | Liang H.,Urban Water Engineering | Luo A.,Dongying Water Supply Company | And 6 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2010

An integrated process of preoxidation, coagulation, sedimentation and ultrafiltration was used to treat algae-rich water and evaluate its algae removal efficiency in pilot experiments. The mitigation and mechanism of membrane fouling by preoxidation with potassium permanganate composites (PPC) is discussed. The results showed that the average algae removal rate increased about 28% with preoxidation at a PPC dosage of 0.6 mg·L-1. When treating algae-rich water with the integrated process, PPC preoxidation could enhance the performance of the pretreatment and control reversible and irreversible membrane fouling by reducing the foulant load on the membrane. The experiment results of chemical cleaning showed that the recovery of transmembrane pressure in alkaline cleaning was much greater than that in acidic cleaning, which indicated that the main foulants on the membrane in the ultrafiltration of algae-rich water were organics.

Chen W.,Hohai University | Yuan Z.,Hohai University | Yuan Z.,Jiangsu Academy of Environmental Sciences | Xu L.,Hohai University | And 3 more authors.
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2012

A pilot test was carried out using ultrafiltration membrane as the core of combined process to treat reservoir water around Yellow river area to study different dosage of KMnO 4 pre-oxidation's effect on organic configuration and ultrafiltration (UF) membrane fouling. The results show that the most part of organic matter is relative molecular mass of more than 3 × 10 3 at the same time the proportion of hydrophilic and hydrophobe organic is almost equal. Coagulation and sedimentation mainly remove the hydrophobic and relative molecular mass of more than 1×10 5 of organic matter and the removal rates are 13.50% and 47.06%, respectively. With the increase of dosage, KMnO 4 pre-oxidation's removal rate of relative molecular mass of more than 1× 10 5 organic increases while producing more 3 × 10 3-1 × 10 5 organic and makes hydrophobic organic from lower to higher. KMnO 4 can reduce membrane fouling when the dosage amount is feasible or can increase the membrane's irreversible pollution when the dosage amount is too high. UF membrane mainly removes hydrophobic organic. The relative molecular mass of more than 1 × 10 5 and 1 × 10 4-1 × 10 5 organic are respectively major factor which causes reversible and irreversible membrane fouling. There are mainly high relative molecular mass and hydrophobic organic in UF backwash waste water and Mn concentration in the waster water of chemical cleaning increases with the increase of dosage of KMnO 4.

Chang H.,Harbin Institute of Technology | Qu F.,Harbin Institute of Technology | Liang H.,Harbin Institute of Technology | Jia R.,Jinan Water and Wastewater Monitoring Center | And 3 more authors.
Journal of Water Supply: Research and Technology - AQUA | Year: 2014

This paper proposed an enhancement start-up strategy for accelerating the start-up of a membrane bioreactor (MBR) for treating micro-polluted surface water under low temperature. The surface water ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) were firstly enriched in a culture apparatus, and they were further acclimated to surface water through an MBR. Then the prepared mixed liquor obtained from the culture apparatus with natural start-up was introduced into new MBRs fed with reservoir water, and the start-up behaviors were discussed. Results indicated that the enrichment of AOB and NOB lasted for 27 days at 7.3 °C and the acclimation (at 5.9 °C) was completed within 3 days. After inoculating with the prepared mixed liquor, the start-up of the MBR was accomplished within 10 days at 9 °C with the flux of 11 L m-2 h-1 (LMH); while operated at lower initial flux (5.5 LMH) and relatively higher temperature (11 °C), it took 3 days for start-up of the MBR. However, the MBRs exhibited stable but not satisfactory organic removals under low temperature during the start-up. © 2014 IWA Publishing.

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