Treatment efficiency of fish processing wastewater in different types of biological reactors

Abstract Fish processing technologies generate a significant amount of organic waste, both solid and liquid. Fish wastewater (FWW), if untreated or ineffectively treated, poses a threat to the aquatic environment. We investigated efficiency of different types of bioreactors with fixed and moving beds in the treatment of wastewater from fish processing. Pollution levels in raw effluents reached 260–660 mg O 2 · dm −3 for BOD 5 , 450–950 mg O 2 · dm −3 for suspended chemical oxygen demand (SCOD), 16.5–23 mg dm −3 for PO 4 3- , and 10–18 mg dm −3 for NH 4 + . It was typical wastewater such as leachate and wastewater after fish processing. The models of bioreactors (on a laboratory scale) identified ring fixed bed reactors (RFBR) as the most efficient under efficient aeration. Average reduction of COD and BOD 5 in RFBR was 44–80%, and 72–77% respectively, and for nutrients, it ranged from 16 to 34% for PO 4 3- and reached 42% for NH 4 + . The other experimental bioreactors were significantly less effective. The application of FRBR in wastewater treatment from fish processing would allow effective reduction of organics pollutants and nutrients concentration in treated effluents.