Biofiltration and biodegradation of wastewater in shrimp farms by a species of sea cucumber, Holothuria leucospilota (Brandt, 1835) from Chabahar Gulf

Biofiltration is a pollution control technique in wastewater treatment, aquaculture, and greywater recycling in which organisms such as sea cucumber and bivalves can be used. In this study, we investigated the integrated bioremediation techniques for a shrimp farm wastewater by sea cucumber, Holothuria leucospilota in the Chabahar Gulf, around the Oman Sea. Furthermore, parameters such as pH, DO, turbidity, NO3 -, PO4 3-, EC, and TDS were evaluated. The concentrations of these parameters were measured in four sampling stations. The results showed that there were significant differences between the parameter values in four sampling stations (P 0.05), the highest concentration being observed in station 3 (outlet wastewater of shrimp farm). In addition, there were significant differences in filtration rates between different periods and different density of sea cucumber (P 0.05), the highest filtration was observed on the 8th day, and at the highest animal density (200). The filtration rates were 8%, 52.5%, 32%, 61.8%, and 55% for EC, NO3 -, turbidity, PO4 3-, and TDS, respectively. Based on these results, H. leucospilota had high capacity for absorption and removal of pollutants from shrimp farm wastewater. Therefore, H. leucospilota is an important species for bio-filtration and improvement of wastewater quality of shrimp and fish farms.