Efficiency of aquatic macrophytes to treat Nile tilapia pond effluents
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Data
2006-10-01
Autores
Henry-Silva, Gustavo Gonzaga
Camargo, Antonio Fernando Monteiro [UNESP]
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Editor
Universidade de São Paulo (USP), Escola Superior de Agricultura Luiz de Queiroz (ESALQ)
Resumo
Os efluentes de piscicultura podem aumentar a quantidade de sólidos em suspensão e promover o enriquecimento de nitrogênio e fósforo nos ecossistemas aquáticos. Neste contexto, o objetivo deste trabalho foi avaliar a eficiência de três espécies de macrófitas aquáticas flutuantes (Eichhornia crassipes, Pistia stratiotes e Salvinia molesta) no tratamento de efluentes do viveiro de tilápia do Nilo. O efluente foi proveniente de um viveiro com 1000 m² contendo 2000 machos de tilápia do Nilo (Oreochromis niloticus). Os sistemas de tratamento consistiram de 12 taques experimentais, três tanques para cada espécie de macrófita estudada, e três tanques sem plantas (controle). Amostras foram coletadas da água de abastecimento do tanque de tilápia do Nilo (i); do efluente do viveiro com tilápia do Nilo (ii) e dos efluentes tratados pelas macrófitas aquáticas (iii). As seguintes variáveis foram determinadas: turbidez, nitrogênio total, nitrogênio dissolvido, N-amoniacal, N-nitrato, N-nitrito, e fósforo total e fósforo dissolvido. E. crassipes e P. stratiotes foram mais eficientes na remoção de fósforo total (82,0% e 83,3%, respectivamente) e nitrogênio total (46,1% e 43,9%, respectivamente) do que quando comparadas com S. molesta (72,1% de fósforo total e 42,7% de nitrogênio total) e com o controle (50,3% de fósforo total e 22,8% de nitrogênio total). Pode-se concluir que as macrófitas aquáticas, principalmente E. crassipes e P. stratiotes foram eficientes na remoção de nitrogênio e fósforo dos efluentes de criação de tilápia do Nilo. Desta forma, o efluente tratado pode ser utilizado nas próprias atividades de aqüicultura.
The effluents from fish farming can increase the quantity of suspended solids and promote the enrichment of nitrogen and phosphorus in aquatic ecosystems. In this context, the aim of this work was to evaluate the efficiency of three species of floating aquatic macrophytes (Eichhornia crassipes, Pistia stratiotes and Salvinia molesta) to treat effluents from Nile tilapia culture ponds. The effluent originated from a 1,000-m² pond stocked with 2,000 male Nile tilapia Oreochromis niloticus. The treatment systems consisted of 12 experimental tanks, three tanks for each macrophyte species, and three control tanks (without plants). Water samples were collected from the: (i) fish pond source water, (ii) effluent from fish pond and (iii) effluents from the treatment tanks. The following water variables were evaluated: turbidity, total and dissolved nitrogen, ammoniacal-N, nitrate-N, nitrite-N, total phosphorus and dissolved phosphorus. E. crassipes and P. stratiotes were more efficient in total phosphorus removal (82.0% and 83.3%, respectively) and total nitrogen removal (46.1% and 43.9%, respectively) than the S. molesta (72.1% total phosphorus and 42.7% total nitrogen) and the control (50.3% total phosphorus and 22.8% total nitrogen), indicating that the treated effluents may be reused in the aquaculture activity.
The effluents from fish farming can increase the quantity of suspended solids and promote the enrichment of nitrogen and phosphorus in aquatic ecosystems. In this context, the aim of this work was to evaluate the efficiency of three species of floating aquatic macrophytes (Eichhornia crassipes, Pistia stratiotes and Salvinia molesta) to treat effluents from Nile tilapia culture ponds. The effluent originated from a 1,000-m² pond stocked with 2,000 male Nile tilapia Oreochromis niloticus. The treatment systems consisted of 12 experimental tanks, three tanks for each macrophyte species, and three control tanks (without plants). Water samples were collected from the: (i) fish pond source water, (ii) effluent from fish pond and (iii) effluents from the treatment tanks. The following water variables were evaluated: turbidity, total and dissolved nitrogen, ammoniacal-N, nitrate-N, nitrite-N, total phosphorus and dissolved phosphorus. E. crassipes and P. stratiotes were more efficient in total phosphorus removal (82.0% and 83.3%, respectively) and total nitrogen removal (46.1% and 43.9%, respectively) than the S. molesta (72.1% total phosphorus and 42.7% total nitrogen) and the control (50.3% total phosphorus and 22.8% total nitrogen), indicating that the treated effluents may be reused in the aquaculture activity.
Descrição
Palavras-chave
Eichhornia crassipes, Pistia stratiotes, Salvinia molesta, aqüicultura, nutrientes, Eichhornia crassipes, Pistia stratiotes, Salvinia molesta, aquaculture, nutrients
Como citar
Scientia Agricola. São Paulo - Escola Superior de Agricultura Luiz de Queiroz, v. 63, n. 5, p. 433-438, 2006.