Research on composting of waste sludge from Catfish processing wastewater treatment plant

Abstract

Catfish is the key and breakthrough export product of Vietnam in recently years. Although most of catfish processing plants invested the wastewater treatment plants (WWTPs), it has not been paid good attention to the treatment of sludge generated from these WWTPs. So far, the sludge has been dumped in landfill. This solution is costly and causes heavy loss of resources containing nutrient. Therefore, this study aims at contributing to finding possible solution to recyle sludge from the WWTPs of catfish processing plants, recover nutrient and limit landfilling.

Aerobic digestion process of mixtures of dewatered sludge from WWTPs of casfish processing plants compress machine and rice straw or sawdust to reduce moisture content, increase C/N and porosity were conducted in 12 aerobic digestion reactors designed as aerated static and windrow composting styles. The best result was obtained with the mixure of 7 sludge: 3 sawdust or 7 sludge: 3 rice traw (in term of wet weight), solid retention time of 18 or 25 days, respectively and the compost produced reached level A of stabilization based on European standard for compost quality (Woods End Laboratory Inc., 2009) and Compost standard 10TCN 526 : 2002 of the Ministry of Agriculture and Rural Development of Vietnam (2002), excepting for total nitrogen.