Phycoremediation by high-rate algal ponds (HRAPs)

Abstract

The disposal of liquid and solid waste in rivers, streams, lakes, and oceans has been occurring for extended periods of time. Increasing industrialization to serve rapidly expanding urban population needs generates large amounts of wastewater that require treatment before release in order to prevent further environmental deterioration. Point source wastewater contamination has the capacity to “overload” receiving water bodies and is the most widespread threat to environmental water quality. Wastewater generally contains high concentrations of organic and inorganic nutrients, which are among the main causes of irreversible ecological degradation. This disrupts the bio-system and natural recycling processes such as photosynthesis, respiration, nitrogen xation, evaporation, and precipitation. Effective wastewater treatment and the use of reclaimed wastewater have great potential to help meet fresh water requirements for various domestic and industrial uses, thus somewhat alleviating the need for water in growing urban centers. In industrial and municipal wastewater, reduction of various chemical stacks at sources is not an easy process and is very expensive to treat by conventional treatment methods due to the demand for skilled operators, high capital investment, high operational costs, reliability etc. Complex operation of conventional treatment methods for removing chemicals does not guarantee sludge reduction. Sludge removal is one of the main challenges in sustainable wastewater treatment, but can be accomplished by the Best Available Technique (BAT) to treat the socio-economic aspect of efcient wastewater treatment. This, coupled with potential energy resource recovery, is mandatory and necessary in exploring the feasibility of biological treatment. There has been growing worldwide interest due to decreasing water resources and increasing demand for preservation and the sustainable management of water resources (Garca et al., 2000).