Wastewater Treatment Plant for Fish, Seafood and Marine Resource Processing Industry

Fishing industry wastewater is highly contaminated. The degree of pollution of a wastewater depends on several parameters. The most important are the type of operation being carried out, the fish species being processed and the operating routine in the factory.

Examples are: fresh fish processing, delicatessen processing (crayfish, crabs, calamari, oysters etc) freezing process, salmon substitute production, canning and herring processing. This Industry is high seasonal.

In general, the wastewater contamination fluctuates, with a high percentage of organic material (undissolved remains, greases, cooking oils, proteins, spices, vegetables

as well as sugar, vinegar) and with high aconcentration of salt, chlorine, cleaning, colouring and disinfection agents.

Processing effluents have high amounts of contaminants such as TSS, biological oxygen demand (BOD), chemical oxygen demand (COD), fat, oil and grease (FOG) as well as nitrogen and phosphorus.

Water plays a key role in Fish processing industry. It is used in every step of the technological lines, including cleaning and washing, disinfection, heating and cooling. Water requirements are huge.

The three major categories according to their origin and composition are:

1. Processing water:

There often is strong variation between flow rates depending mainly on the plant operations. Effluent’s can be split into 2 categories: high salinity waste waters from the products or the utilization of seawater in part of the process and low salinity waste waters, where fresh water is used and no salinity is produced as a by-product.

2. Cleaning wastewater:

Cleaning wastewater usually comes from washing equipment which is in direct contact with the product. It also includes product spillage, pressing and brine, CIP effluents or equipment malfunction and even operational errors. These effluents are in large quantities and are highly polluted, thus requiring further treatment.

3. Sanitary wastewater:

Sanitary wastewater is found in lavatories, shower rooms, etc. Sanitary wastewater is similar in composition to municipal wastewater and is generally piped directly to sewage works, but it can be used as a nitrogen source for unbalanced effluents before a secondary aerobic treatment.