Ren Hongqiang

A review of membrane fouling in municipal secondary effluent reclamation

Reclamation of municipal secondary effluent for non-potable purposes is considered vital in alleviating the demand for existing limited water supplies while helping to protect remaining water sources from being polluted. In recent decades, reverse osmosis and nanofiltration membrane technologies have become increasingly attractive for reclamation of municipal secondary effluent because they are highly efficient, easy to operate, and economical. However, membrane fouling is a major obstacle in the development of membrane technology in municipal secondary effluent reclamation. This paper reviews three types of membrane fouling in municipal secondary effluent reclamation, namely, effluent organic matter (EfOM) membrane fouling, microbial membrane fouling, and inorganic membrane fouling, as well as their correlation. Membrane fouling by EfOM and microbes are found to be severe, and they are significantly correlated. Most previous studies conducted laboratory-scale experiments of membrane fouling with model organic matters and bacteria, but these model organic matters and bacteria might still be unrepresentative. More studies on membrane fouling in municipal secondary effluent reclamation with actual wastewater are essential.

Advanced Treatment of Vitamin C Wastewater by Coupling Electrochemical Oxidation and an Integrated Bioreactor

AbstractThis study aims to establish a new technology for the advanced treatment of vitamin C (VC) wastewater by coupling electrochemical oxidation (EO) and an integrated bioreactor. Characteristics of organic compounds in the effluent from biotreatment of VC wastewater were analyzed. EO was used to break the chromophore functional groups of these organic compounds and improve biodegradability of the effluent. The subsequent integrated bioreactor was proposed to further degrade organic compounds in the effluent from the EO. The optimum operation parameters of this combined technology and the effect of cosubstrate on the removals of color, chemical oxygen demand (COD), and nitrogen were investigated. EO could remove color with the maximum removal of 183° and improve the biochemical oxygen demand-to-COD ratio effectively from 0.07 to 0.24. Effluent COD and color of the integrated bioreactor decreased from 111.4  mg/L and 60° without glucose addition to 100.9  mg/L and 50° with glucose addition. Concomitantl...

Nitrification Behavior of Ammonium Nitrogen Under Membrane Bioreactor

The behavior of CODMn and NH4 +-N removal under an integrated and submerged MBR was investigated, the plate membrane shows better stability in filtration during the long period of operation, and the removal efficiency of COD reached as much as 80%, but that of NH4 +-N was below 50%, This findings may be largely responsible for the relative lower pH value of the sludge, which could severely hinder the nitrification ability of nitrifying bacteria. Consequently, out of pH control, the reactor maintains its pH value at about 5.4.