The Effect of Adding Wood Chips on The Decomposition of Sludge from Seafood Processing Wastewater Treatment System

This study evaluates the effect of various wood chips on the sludge decomposition process. Sludge from Surimi processing wastewater treatment system (AS) of Danifood factory in Danang city was mixed with local wood chips as bulking agents (BA) including Khaya senegalensis (D), Acasia (A) and sawdust (S). The weight ratio of AS/BA added to each aerobic model was 1:1, 1.5:1 and 2:1 for K, A and S, respectively. The results showed that variations of temperature and pH were suitable for aerobic biochemical process. K and S model reached 50 °C in three days and remained stably for next four days, whereas A reached 50 °C after ten days and remained stably for six days. The value of seed germination index from decomposed sludge was more than 80% for K and A whereas 48 - 60 % for S. It is necessary to consider the type or composition of sawdust when utilize it as a BA. In addition, the TOC and T-N of AS after decomposition met Vietnamese standard for organic fertilizer quality, so they could be used to supply nutrients to plants. This study is an important basis for the BAs selection to conduct experiments aim at AS recovery.