Ecological Water Treatment System for Removal of Phosphorus and Nitrogen From Polluted Water

Abstract

We propose that phosphorus and nitrogen can be removed from polluted water using an ecological water treatment system consisting of periphyton and fish. In the proposed system, polluted water flows through a series of vessels, and the nutrients are taken up by periphyton growing on porous screens. Algal-grazing fish feed on the periphyton and either assimilate or egest the nutrients in mucus-bound feces that settle from the water into a sediment trap. Both the fish and their feces can be harvested as nutrient sinks. In this study we examined the effects of an algal-grazing cichlid (Tilapia mossambica) and a stoneroller minnow (Campostoma anomalum) on nutrient removal by the proposed water treatment system. In two experiments using tank-mesocosms, we found that the algal-grazing fish consumed the periphyton and transferred nutrients into the fish's body tissues or the sediments. The mass of phosphorus sequestered in the nutrient sink in the body tissues of the fish was approximately equivalent to the phosphorus sink in the sediments. High removal rates for phosphorus and nitrogen suggest that the proposed ecological water treatment system may be an effective ecotechnology for removal of nutrients from polluted water.

Algal Productivity and Nitrate Assimilation in an Effluent Dominated Concrete Lined Stream

“…Therefore, the mean accumulation rate observed in Cucamonga Creek (13.2 g dry weight/m 2 /d) is in the range reported for these treatment systems. Such biological treatment systems include wetlands (Gersberg et al, 1983;Phipps and Crumpton, 1994;Van Oostrom and Russell, 1994;Van Oostrom, 1995;Eriksson and Weisner, 1997;Stober et al, 1997), tank mesocosms (Drenner et al, 1997;Rectenwald and Drenner, 2000), artificial streams (Adey et al, 1993Craggs et al, 1996;Mariñelarena and Di Giorgi, 2001), high rate algal ponds (Gianelli, 1971;Nurdogan and Oswald, 1995;Green, et al, 1996;Hoffmann, 1998;Mulbry and Wilkie, 2001;Wilkie and Mulbry, 2002), and wastewater treatment lagoons (Reed, 1984;Silva et al, 1995;Green et al, 1996;Hurse and Connor, 1999;Maynard et al, 1999).…”

Wastewater Treatment With Suspended and Nonsuspended Algae

“…For both systems, it is likely that a more integrated approach in the context of ecological engineering at the ecosystem level will be emphasized. The work by Drenner et al (1997) on a periphyton-fish treatment system is a recent example of this approach. The fundamental principles of the ecological design of these living technologies for wastewater treatment have recently been summarized by Todd and Josephson (1996) and underlie the applications described by Guterstam (1990) and Teal and Peterson (1991).…”

Contribution of omnivorous tilapia to eutrophication of a shallow tropical reservoir: evidence from a fish kill

“…(2) Removal of P in dead fish biomass. The 150 tons of tilapia wet weight correspond to a dry weight (DW) of 36 tons (using a DW : WW ratio of 24%; Drenner et al, 1997) and 857 kg of P (using a P-content of 2.39% of fish dry weight). This amount is equivalent to the external loading received by Riacho Fundo branch during 20 days after tilapias had been removed.…”