A comperative study on nitrogen removal efficiency of seaweed species (Kappaphycus alvarezii and Eucheuma denticulatum) from aquaculture wastes.

Abstract

Seaweeds have been applied broadly in aquaculture activities. This project is to investigate a comparative study on the capacity of two seaweed species Kappaphycus alvarezii and Eucheuma denticulatum in absorbing nitrogen from aquaculture discharge water. Effluents of cultivation tanks of Red Tilapia were used as aquaculture discharge water for this study. In this study, there was no significant difference between two seaweed species in removing nitrogen from discharge water (p>0.05), but they were good bio-filters. Specifically, removal efficiency of K. alvarezii was 40.50±13.29%, 84.64±5.43% and 54±8.43% for nitrate concentration, nitrite concentration and total organic nitrogen, respectively. This capacity of E. denticulatum was 47.40±11.37%, 87.68±3.34% and 51.34±12.20% for nitrate concentration, nitrite concentration and total organic nitrogen, respectively. In addition, the seaweeds harvested can be a substantive source used for the carrageen industry and food products. Apparently, fish weight after 30 days was highly significant difference compared with the initial weight (p<0.05), but there was no significant difference between fish tanks cultured in the seaweed tanks (p>0.05). This study showed the effect of the seaweeds in bioremediation of aquaculture wastes.

Keywords: Kappaphycus alvarezii, Eucheuma denticulatum, nitrate, nitrite, total organic nitrogen.