Satisfactory disposal of wastewater, whether by surface, subsurface methods, or dilution, is dependent on its treatment prior to disposal. Adequate treatment is necessary to prevent contamination of receiving waters to a degree which might interfere with their best or intended use, whether it be for water supply, recreation, or any other required purpose. The sewage treatment technologies have proven to be expensive, complex and are failing to cater to the total wastewater generated. The untreated/partially treated wastewater makes its way to the water body causing immense degradation of the ecosystem and the environmental health. Some effective, advanced treatment technologies take high construction and maintenance costs, high energy consumption. Need of the hour is to develop some sustainable treatment technologies - to locally treat the sewage and reuse. The decentralized sewage treatment can be both electro-mechanical system that have higher energy requirement or natural eco-friendly systems with less energy requirement. Substantial efforts are being made to document, understand, and explain the science behind these issues all over the world. The DHS (Down-flowHangingSponge) Bio-Tower based on anammox process in combination with UASB (Upward Flow Anaerobic Sludge Blanket) is one of the sustainable systems for waste water treatment & well suited for tropical and subtropical countries. The DHS Bio-reactors employing different sizes of sponge media exhibit excellent performance in removal of BOD, COD, and ammonium nitrogen at a fixed hydraulic retention time. Wastewater is trickled from the top of the reactor and allowed to flows vertically down through the reactor containing microorganisms retained both inside and outside of the sponge media. The resultsofinvestigationsshow that smaller sponge media produced better removal efficiencies may be due to better oxygen uptake in the stream flowing down through reactor.

Anammox Process, Sustainable Methods, Toxic Chemicals, Waste Water