Haijia Su

Adsorption of Ni2+ on the surface of molecularly imprinted adsorbent from Penicillium chysogenum mycelium.

The adsorption capacity for Ni2+ on to the surface molecular imprinting adsorbent on Penicillium chysogenum mycelium (the surface-imprinted adsorbent) was 40–45xa0mgxa0g−1 (using 200xa0mg Ni2+xa0l−1), two times of the mycelium adsorbent. The surface-imprinted adsorbent had good stability at pHxa02∼8. The optimal concentration of EDTA for desorption was 0.1 to 0.5xa0gxa0l−1. The surface imprinted adsorbent could be reused 15 times without losing its uptake.

Role and influence of extracellular polymeric substances on the preparation of aerobic granular sludge.

Due to the important role of the extracellular polymeric substances in the formation of aerobic granular sludge, the variation of the EPS contents in the process of cultivation and that in the one running cycle time were studied in this work. Aerobic granules with diameters between 0.8 and 1.1xa0mm were obtained within 30-35 days. The results suggested that the increase of EPS contents significantly contributed to the formation of aerobic granules. A linear relationship between the EPS and SVI was also developed, and it revealed that the aerobic granules had good settling property when the EPS exceeded 200xa0mg/g MLVSS. Two mainly components of EPS, protein (PN) and polysaccharides (PS), could act as the endogenous food for the microbes during the starvation period. The survival of the microbial population was jeopardized when the F/M ration was below 0.5xa0g COD/g SSxa0d.

Influence of an aniline supplement on the stability of aerobic granular sludge.

In order to evaluate the stability of aerobic granules in a toxic environment, this study discussed the influence of an aniline supplement on the properties and microbial community of aerobic granules. In the early stages of sequencing batch reactor (SBR) operation, an aniline supplement slightly affected the properties of the aerobic granules (strength, growth rate, SVI and so on). This effect was thereafter removed because of a change in the microbial community and the structure of aerobic granules: with the present of aniline, microbes with biodegradation ability appeared and gathered in the aerobic granules and the aerobic granules densified and settled faster as their SVI decreased to 35xa0mL/g and settling velocity increased to 41.56xa0m/h. When a synthetic waste water containing acetate as carbon source was used as influent, aniline (10-500xa0mg/L) could be degraded in 6xa0h, at a rate as high as 37.5xa0mg aniline/(L·h), with a removal rate in excess of 90%, while the effluent COD fell below 100xa0mg/L from the initial about 2000xa0mg/L. The aerobic granules cultured by acetate were compact, stable and resistant to aniline.

Analysis of aerobic granules under the toxic effect of ampicillin in sequencing batch reactors: Performance and microbial community

To study the change of the aerobic granules microbial community in the present of antibiotics, ampicillin (AMP) was selected as a model component. With acetate as carbon source, different concentrations of AMP (5, 10 and 15xa0mgxa0L-1) were applied to the inflow intermittently and the results showed that the stability of the aerobic granules was maintained below 10xa0mgxa0L-1 AMP. Simultaneously, under exposure to 5 and 10xa0mgxa0L-1 AMP, the COD removal efficiency in the batch reactors remained at 86% and AMP was degraded almost completely with a removal efficiency of 97%. However, the EPS concentration and dehydrogenase activity decreased constantly with increasing AMP dosage. High-throughput sequencing analysis revealed that Proteobacteria was the most prominent phylum in the whole experiment and contributed to the degradation of AMP. The percentages of Azoarcus and Mycoplana increased at 10xa0mgxa0L-1 AMP. In addition, Hydrogenophaga and Enterococcus played a key role in the microbial metabolism.

Combining microwave irradiation with sodium citrate addition improves the pre-treatment on anaerobic digestion of excess sewage sludge

This study investigated the synergistic effect of sodium citrate (SC; Na3C3H5O(COO)3) and microwave (MW) treatment on the efficiency of the anaerobic digestion of excess sewage sludge. In terms of the methane yield, an increase of the digestions efficiency was observed. Taking into account the cost for the MW energy supplied to the system, the optimum treatment conditions were a MW energy input of 20u202fMJ/kg TS and a SC concentration of 0.11u202fg/g TS, obtaining a methane yield of 218.88u202fml/g VS, i.e., an increase of 147.7% compared to the control. MW treatment was found to break the sludge structure, thereby improving the release of extracellular polymeric substances (EPS) and volatile fatty acids (VFAs). The treatment of sodium citrate further strengthened the breakage of loosely bound extracellular polymeric substances (LB-EPS) and tightly bound extracellular polymeric substances (TB-EPS). The increased VFA content stressed the improved digestion by this pretreatment. Furthermore, the preliminary economic analysis showed that at this point in the research, only operational but no financial gains were achieved.