Phytoremediation of freshwater crayfish (Cherax quadricarinatus) culture wastewater with spinach (Ipomoea aquatica) in aquaponic system

Aim of the study was to compare the ability of nutrient reduction of freshwater crayfish (Cherax quadricarinatus, family Parastacidae) wastewater cultured in aquaponic system using vegetable plant, water spinach (Ipomoea aquatica). Aquarium A - rearing freshwater crayfish without plant, and aquarium B - rearing freshwater crayfish with water spinach, were experimented for three weeks. Survival rates of crayfish were 85% (aquarium A), and 90% (aquarium B). Meanwhile mortality of crayfish was 15% and 10% at aquarium A and B, respectively. Aquaponic system applying water spinach can reduce freshwater crayfish culture wastewater particularly ammonia (NH3) until 84.6%, and nitrate (NO3) until 34.8%. Orthophosphate underwent reduction of 44.4% under spinach treatment. Relatively high ammonia concentration in control without plant treatment (aquarium A) affected the growth of freshwater crayfish. Hence, the survival rates of freshwater crayfish grown together with plant were higher than that without plant.