Activated sludge (AS) plays a crucial role in the treatment of domestic and industrial wastewater. AS is a biocenosis of microorganisms capable of degrading various pollutants, including organic compounds, toxicants, and xenobiotics. We performed 16S rRNA gene sequencing of AS and incoming sewage in three wastewater treatment plants (WWTPs) responsible for processing sewage with different origins: municipal wastewater, slaughterhouse wastewater, and refinery sewage. In contrast to incoming wastewater, the taxonomic structure of AS biocenosis was found to become stable in time, and each WWTP demonstrated a unique taxonomic pattern. Most pathogenic microorganisms (Streptococcus, Trichococcus, etc.), which are abundantly represented in incoming sewage, were significantly decreased in AS of all WWTPs, except for the slaughterhouse wastewater. Additional load of bioreactors with influent rich in petroleum products and organic matter was associated with the increase of bacteria responsible for AS bulking and foaming. Here, we present a novel approach enabling the prediction of the metabolic potential of bacterial communities based on their taxonomic structures and MetaCyc database data. We developed a software application, XeDetect, to implement this approach. Using XeDetect, we found that the metabolic potential of the three bacterial communities clearly reflected the substrate composition. We revealed that the microorganisms responsible for AS bulking and foaming (most abundant in AS of slaughterhouse wastewater) played a leading role in the degradation of substrates such as fatty acids, amino acids, and other bioorganic compounds. Moreover, we discovered that the chemical, rather than the bacterial composition of the incoming wastewater was the main factor in AS structure formation. XeDetect (freely available: https://sourceforge.net/projects/xedetect) represents a novel powerful tool for the analysis of the metabolic capacity of bacterial communities. The tool will help to optimize bioreactor performance and avoid some most common technical problems.

Budiasa IW, Santosa IGN, Ambarawati IGAA, Suada IK, Sunarta IN, Shchegolkova N. 2018. Feasibility study and carrying capacity of Lake Batur ecosystem to preserve tilapia fish farming in Bali, Indonesia. Biodiversitas 19: 563-570. Lake Batur in Bangli District was potential for fishery development up to 5% of the total water area. Currently the lake area used for fishery was only 6.28 ha, leaving the area up to 77.07 ha potential for fishery development. Tilapia (Oreochromis niloticus) was the most abundant fish in the lake. This research aimed to evaluate the financial feasibility of tilapia fish farming with Floating Net Cages (FNC) technology within the lake and to assess its carrying capacity for the tilapia aquaculture. Discounted investment criteria were used to test farm survey data from 30 tilapia fish growers at top three villages which had the largest number of FNC. Six water samples were taken using deep water sampler at three sampling points were analyzed to see a number water chemistry and physics condition. The results showed that economic life of a FNC was financially feasible as indicated by the positive Net Present Value (NPV), Internal Rate of Return (IRR) was greater than 9% and Net Benefit Cost Ratio (Net B/C) was greater than one; and however the water quality as indicated by value of TDS, NO2, BOD, Total-P, NH3, and P-PO4 exceeded the maximum limit of water quality criteria class II based on Government of Indonesia Regulation No. 82/2001. Thus, FNC should not be more expanded within the lake due to water pollution of the lake.

Plants, fungi, bacteria and protozoa are highly interconnected in constructed wetlands. These heterogeneous groups of organisms constitute a single system with complex internal trophic interactions. Thus, the joint activity of micro- and macroorganisms in constructed wetlands provides highly efficient wastewater treatment: both nutrients and complex organic substances can be effectively removed in branched trophic chains. The bacterial community of constructed wetlands has recently received much attention, while the fungal component remains less studied, particularly saprotrophic fungi. This paper reveals a taxonomic analysis of the cultivated saprotrophic fungi combined with the bacterial community in vertical flow constructed wetlands (VSCWs) operated by the Azoé-NP® process. These systems have unique features to affect the microbial community, which results in a high treatment efficiency and nitrogen removal. There are very few studies of saprotrophic fungi in VFCWs, while this work shows their abundance and diversity in VFCWs. We found 62 species of cultivated microscopic fungi and described the taxonomic composition of bacterial and fungal community at all wastewater treatment stages. In the studied VFCWs, we identified the species of micromycetes, which proved effective in the removal of contaminants. The data obtained can provide a deeper insight into the characteristics of Azoé-NP® systems and the treatment processes occurring in constructed wetlands.