Preliminary evaluating the possible use of water-decanted sludge from seafood processing wastewater treatment to raise Peryonyx excavatus

The study was conducted to evaluate the possibility of using sludge from processing seafood after dehydration to grow earthworm (Peryonyx excavatus). The worms (purchased from the Xuan Nong worm farm) were raised with a density of 5,000 individuals in three plastic drums with dimensions of LxWxH of 60x42x18 cm. Plastic drums contain a layer of coconut fiber in the bottom and sludge layer above. At the bottom of the plastic drums there are several drainage holes with a diameter of 5mm which could let the water out but not the worms. Soil samples were collected before and after the experiment to analyze the parameters of temperature, pH, humidity, total nitrogen (Nt), total potassium (Kt), total phosphorus (Pt). The results showed that the sludge after raising earthworms has the nutrient components increased significantly. Nt increased from 0.7% to 3.32%, Pt from 0.675% to 3.381%, and Kt from 0.046% to 0.245% compared to input sludge. E. coli was not detected and coliform was reduced to a level that is safe for human health. The use of sludge from the wastewater treatment system of the seafood processing company for raising Peryonyx excavatusbrings benefits since it both brings an additional income, and converts sludge into organic fertilizer, contributing to solving environmental problem.