Project description:Effluents from sewage treatment plants contain a mixture of micropollutants with the potential of harming aquatic organisms. Thus, addition of advanced treatment techniques to complement existing conventional methods has been proposed. Some of the advanced techniques could, however, potentially produce additional compounds affecting exposed organisms by unknown modes of action. In the present study the aim was to improve our understanding of how exposure to different sewage effluents affects fish. This was achieved by explorative microarray and quantitative PCR analyses of hepatic gene expression, as well as relative organ sizes of rainbow trout exposed to different sewage effluents (conventionally treated, granular activated carbon, ozonation (5 or 15 mg/L), 5 mg/L ozone plus a moving bed biofilm reactor, or UV-light treatment in combination with hydrogen peroxide). Exposure to the conventionally treated effluent caused a significant increase in liver and heart somatic indexes, an effect removed by all other treatments. Genes connected to xenobiotic metabolism, including cytochrome p450 1A, were differentially expressed in the fish exposed to the conventionally treated effluents, though only effluent treatment with granular activated carbon or ozone at 15 mg/L completely removed this response. The mRNA expression of heat shock protein 70 kDa was induced in all three groups exposed to ozone-treated effluents, suggesting some form of added stress in these fish. The induction of estrogen-responsive genes in the fish exposed to the conventionally treated effluent was effectively reduced by all investigated advanced treatment technologies, although the moving bed biofilm reactor was least efficient. Taken together, granular activated carbon showed the highest potential of reducing responses in fish induced by exposure to sewage effluents.
2012-05-10 | GSE37574 | GEO
Project description:Microbial community of urban sewage treatment plants in Xinjiang
Project description:Phosphorus (P) limitation will play a key role in the productivity of agriculture in the coming decades. Struvite is an ammonium magnesium phosphate mineral that can be recovered from wastewater-treatment plants and can be considered as an alternative source of P. However, the impact of struvite on the plant yield and, particularly, on the soil microbial community is barely known. Here, we tested the impacts of struvite, sewage sludge, and their combination on the barley yield, soil macro and micronutrients, and biochemical and microbiological soil properties. Amendment with struvite alone and its combination with sludge increased the availability of P in soil, the plant uptake of P and Mg, and the barley yield. The analysis of phospholipid fatty acids (PLFAs) and metaproteomics approaches revealed significant effects of struvite on the biomass of Gram-positive bacteria and, particularly, on actinobacterial populations in soil.