Abstract—Presently world is facing mounting water stress, both in quantity and quality, which has prompted many municipalities for a more efficient use of the water resources, including a widespread acceptance of water reuse practices. Treatment technology encompasses a vast variety of options. As a low-cost, eco-friendly approach constructed wetlands are recently promoted for wastewater treatment and end use applications of reclaimed water. The present study was conducted to assess the performance of a series of treatment wetlands (waste stabilization ponds) in wastewater purification in Kalyani, West Bengal, India in the perspective of reclamation and bioregenerative reuse of reclaimed wastewater. The waste stabilization ponds have been proved very efficient and cost-effective nature-based system for increasing the ecological value of wastewater in culturing aqua-crops and thus converting organic wastes into fish biomass. Index Terms—Heterotrophic bacteria, fish, nitrogen, phosphorus, regenerative reclamation, treatment wetlands, wastewater. I. INTRODUCTION Wastewater generates from point and diffused municipal and industrial sources and contains a vast array of chemical substances–a cocktail of both helpful and harmful ones. Continuous discharge of wastewater from diverse anthropogenic activities into the natural system is creating material imbalance and adversely affecting the aquatic ecology. Typical municipal sewage treatment plant requires high capital investment, technical expertise and is energy-intensive. In developing countries, such treatment plants are not considered as an economically viable option. Treatment should not also let the nutrient-enriched wastewater down the drains and nutrients and water should be reused in productive use by closing the nutrient loop [1]. Treatment wetland systems exemplify systems of low-cost, low-tech, low maintenance and minimal energy demanding system and therefore, can be promoted as appropriate eco-based solutions to wastewater problem. Recently there has been a major shift in reclamation strategies from costly conventional technology to low-cost, eco-friendly, sustainable eco-technology using living machines, hypolimnetic aeration, and treatment wetlands. Biological wastewater treatment includes all methods that involve organisms, and emulate at least some of the natural ecosystem processes. Several biological treatment systems emulate decomposer communities wherein degradation Manuscript received April 14, 2013; revised July 2, 2013. The authors are with International Centre for Ecological Engineering, University of Kalyani, Kalyani, Nadia 741235, India (e-mail: biswajoy2000@yahoo.com, sukanta_rana@rediffmail.com). Jayanta K. Biswas and Sukanta Rana processes predominate (treatment with activated sludge) and others emulate productive ecosystems where assimilation is important (wastewater-fed aquaculture). A World Bank report [2] strongly advocated for waste stabilization ponds as low-cost, effective and sustainable systems to be used for wastewater treatment and reuse in agriculture. Another important way of utilizing wastewater in economic activities is aquaculture where income of essential elements such as nitrogen, phosphorous, organic carbon from sewage can be converted into biomass resource. Wastewater-fed aquaculture, therefore, offers means to treat wastewater with integrated material-flow recycling. West Bengal is the pioneering state in India where such age-old, innovative and effective practices are underway involving many sewage-fed fish farms. Kalyani is a modern town of West Bengal established in 1945 with a well-planned underground sewerage system. A sewage treatment plant was constructed in 1993 under Ganga Action Plan (GAP) receiving 17×10 6 ld -1 of domestic wastewater from about 82000 inhabitants of the township. Of the total amount of sewage generated per day, about 11×10 6 l is treated through conventional treatment plant, whereas the remaining 6x10 6 l enters into a series of stabilization ponds before being discharged into the river Ganga. Wetlands improve water quality by acting as sediment sinks, filters and sponges for nutrients and toxicants. They are rightly regarded as ‘nature’s kidneys’ or ‘nature’s liver’ owing to their filtering and clean-up functions. Removal of pollutants relies on a combination of physical, chemical and biological processes naturally occurring in wetlands and are associated with vegetation, sediments and their microbial communities. As biologically active ecosystems bolstered with many active bio-filters wetlands transform many pollutants at a high rate and have increasingly been used for wastewater treatment [3]. Considered as complex bioreactors in natural setting wetlands’ ability to transform and trap organic matter and nutrients has been harnessed in constructed wetlands. Such wetlands are appropriate, low-cost, ecologically-based solutions, particularly for treating and reusing municipal sewage in developing regions. The central aim of the system is wastewater purification and nutrient assimilation into biomass. These artificial treatment systems consist of shallow ponds planted with aquatic plants. Being the man-made mimics of natural wetlands they optimally exploit the biogeochemical cycles and have evolved into a reliable treatment technology for wastewater reclamation and remediation [4]. The reduction of ubiquitous parameters like BOD, COD, total suspended solids and nutrients, pathogens, Jayanta K. Biswas and Sukanta Rana Treatment Wetlands as Ecotechnological Tools for Regenerative Reclamation of Wastewater: Experiences from Working with Kalyani Model Journal of Clean Energy Technologies, Vol. 2, No. 1, January 2014 23 DOI: 10.7763/JOCET.2014.V2.84