Biodegradation of fish wastes in a 5-l ribbon-type reactor for re-utilization as a liquid fertilizer

Abstract

The amount of fisheries waste generated in Korea is expected to increase with a steady increase in population to enjoy taste of slices of raw fish, which urger us to seek for an effective treatment of fish waste. To re-utilize fish waste as a fertilizer, eleven microorganisms were isolated from composting site and internal organs of earthworm, which showed active biodegradation of fish waste. Biodegradation was carried out in a 5-l ribbon-type reactor using fish wastes for seven days. By the active biodegradation, the weight of dry solid in the reactor was decreased with disappearance of fishy odor. The cell number increased, and pH decreased slowly. After biodegradation, hydroponic cultures of red bean and barley were carried out at various dilution ratios with the biodegraded broth, which is fit for test of its fertilizing ability. Elongation of root was slow after seed germination in all diluted broths of fish waste. However, roots elongated soon after development of root. The fastest growth was achieved at 500-fold dilution for both plants.