[Enhanced Membrane Anti-fouling Ability of Anaerobic Membrane Bioreactor Equipped with Bio-electrochemical System Using Nano-zero-valent Iron and Its Regulation Mechanism].

Membrane fouling is the biggest challenge of membrane bioreactor industrialization. In this study, a bio-electrochemical system (BES)-anaerobic membrane bioreactor (AnMBR) system was constructed, and the effect of nano-zero-valent iron (nZVI) on membrane anti-fouling ability and methane production was investigated. The results showed that the BES-AnMBR system was stable and the chemical oxygen demand (COD) removal rate was maintained at approximately 95%. The optimum condition was observed to be nZVI 0.1 g·g-1(VS). Under this condition, transmembrane pressure (TMP) was reduced by 28.1%, the membrane flux had a slight improvement, and methane production was up to 81.3 mL·g-1(CODremoved). This was 12.1% higher than that of the control. In addition, a further analysis of extracellular polymeric substances (EPS) fraction and membrane resistance showed that nZVI enhanced EPS decomposition, promoted the formation of an iron-rich layer of inorganic and organic matters on the membrane surface, and changed the distribution of organics and inorganics, thereby significantly alleviating membrane fouling. This study will enrich basic theory of conventional AnMBR and provide a new solution for efficient sludge treatment and resource utilization.

[Feeding ecology of Conger myriaster and structure of the food webs in artificial reef zone, Laoshan Bay, China]. / 崂山湾人工鱼礁区星康吉鳗摄食生态及食物网结构.

Based on cage net and longline fishing surveys in Laoshan Bay, China, from April 2015 to January 2017, a total of 279 Conger myriaster stomach samples were analyzed to study their feeding ecology, including diet composition, feeding type, feeding grade, feeding intensity, trophic niche, and trophic level. The stomach content analysis of nine key fish species (including Sebastes schlegelii, Hexagrammos otakii, Hexagrammos agrammus, Sebastiscus mamoratus, Lateolabrax maculatus, etc.), were conducted to examine the food webs in artificial reef zone. The results showed that the diet of C. myriaster consisted of more than 30 species belonging to seven orders, in which shrimps were the most dominant prey species, followed by fishes and cephalopods. The dominant species in the diet of C. myriaster were H.otakii, Enedrias fangi, Trachypenaeus curvirostris, Ammodytes personatus and Alpheus japonicas. The diet composition of C. myriaster varied with season and anal length. Fishes and shrimps were the two important groups throughout the years. Cephalopods were predominant in spring. Cephalopods and crabs were predominant in Autumn. Fish eggs were eaten mostly during winter. Fish eggs and T. curvirostris were the dominant prey groups of the C. myriaster with anal length ≤120 mm, whereas A. personatus and A. japonicas were the dominant prey groups of the C. myriaster with anal length 120-130 mm, H.otakii and E.fangi were the dominant prey of the C. myriaster with anal length ＞130 mm. The percentage of empty stomach of C. myriaster varied significantly with season, but the mean stomach fullness index did not. The percentage of empty stomach and mean stomach fullness index did not differ significantly among different anal length groups. The trophic levels of the key fish species were higher than level 3, with C. myriaster at the top of food webs (with a trophic level of 4.636). Decapoda, crabs, amphipoda and molluscs were the main prey of key fish species, while Crustaceans, E. fangi, H. otakii and A. personatus were the main preys of L. maculatus and C. myriaster.