Performance evaluation of silica nanoparticles modified with Pumice reduce the amount of nitrate (NO3) and phosphate (PO4) in wastewater effluent water from fish farms

Effluents from fish farms have high levels of nitrate and phosphate. In the present study, the removal of nitrate and phosphate from aquatic farm effluent was investigated by nanosilica adsorbent modified with mineral pumice. For this purpose, the desired adsorbent was added to 250 ml of effluent (with 50% and 100% concentration) in laboratory conditions (adsorbent doses of 0.01, 0.05, 0.1, 0.5 and 1 g/l). Nitrate and phosphate concentrations in the effluent were measured before the experiment. According to the results, the highest amount of nitrate and phosphate removal at a dose of 0.5 g/l was selected as the optimal dose, so the nitrate and phosphate removal efficiency was decreased at concentrations higher than this amount, because the available active ingredient was reduced at doses higher than 0.5 g. In this experiment, the optimum contact time of the adsorbent with the contaminant was 45 minutes. It seems that modified nanosilica with mineral pumice has a high ability (86% efficiency) to remove nitrate and phosphate from aquaculture effluents and can be used to purify effluents from aquaculture farms before reuse in the return system or before entering to the environment.