This compilation opens by presenting a discussion on the main conditions for the successful start-up and operation of full-scale mainstream partial nitrification-anammox technology, advantages of partial nitrification-anammox technology over other technologies of wastewater treatment, and a description of the interactions among key microbial groups and their identification by using metagenomic approaches. Next, one study elucidates the performance of anammox hybrid reactors under various operating conditions to optimize and assess its efficacy and feasibility for nitrogen removal from wastewater. Four numbers of hybrid reactors conglomerating the dual advantages of attached and suspended growth were designed and investigated. The authors seek to produce a soil erosion susceptibility map with selected parameters including elevation, slope, aspect, slope curvature, stream power index, topographic wetness index, cover management factor, land use/land cover, rainfall erosivity, soil erodibility, lineament density, distance from lineament, and distance from stream and drainage density. The weighted linear combination method is applied using remote sensing and geographical information system techniques in the Shiri river basin of Darjeeling, Himalaya. The following study addresses the financial and economic benefits of tourism, and whether these economic benefits are to the detriment of the natural environment. This is done by conducting an investigation into community fishing practices around Mnemba Island. Semi-structured interviews were held with Mnemba Island Lodge staff, local fishermen and local authorities involved in the fisheries around Mnemba Participatory observations were also used to support the data collected by the semi-structured interviews. The authors present data suggesting that of insolation is of high importance for the structuring of floodplain ecosystems because it has potential to impact floodplain lakes regardless of flooding. It is proposed that future investigations of floodplain aquatic habitats should take into account insolation effects other than those of hydrology. The closing chapter provides a brief review of anchovy characteristics, habitats, use, and eco-friendly treatment of anchovy waste/wastewater for reutilization. Anchovy is an attractive resource for the production of functional compounds such as antimutagenic, antifungal, antioxidant and antibacterial agents.