|
Seafood Processing
 The slaughtering of live seafood (crab, flounder, catfish, shellfish, tuna, menhaden, etc.) generates significant waste. These wastes may be highly concentrated depending on species. Disposing of these wastes generally require permits from state and federal environmental agencies to ensure minimal environmental impact. These wastes include solids (e.g., eggs, heads, shells, eviscera, etc.) and liquids (e.g., blood, cook water, washwater, chilling water, cleaners, sanitizers, etc.). Solid waste are typically separated and sold (e.g., fish meal) or disposed of (e.g., landfill or compost) depending on economic markets. Solid waste or liquids that end up in the liquid waste stream are collectively referred to as wastewater. The percentage of solid waste generated from each species ranges from about 0% for fish which are completely processed such as menhaden to approximately 85% for blue crab. The average percentage solid waste to raw product for all seafood is about 30%. Table 1 shows a sample of wastewater characteristics for a discharge from a traditional (non-mechanized) blue crab processing facility. Before being discharged this wastewater would need additional treatment to reduce regulated components (e.g., TSS, FOG, COD, TKN, Total Phosphorous) by 10 to 100 times. Wastewater concentrations in seafood processing varied widely with manufacturing process. For example, wastewater from a fish meal processing plant can have COD concentrations greater than 30,000 mg/L.
Permits required for seafood processing vary with the type of manufacturing (filleting (slaughter), picking, canning, packaging). The wastewater permit may be a municipal permit for those discharging into a publicly owned treatment works (e.g., city or municipality) or a National Pollution Discharge Elimination System (NPDES) permit if the facility treats its own wastewater and directly discharges into the environment. These permits specify maximum allowable limits for discharge parameters such as total flow, BOD5, COD, FOG, TKN, and Total Phosphorous. These limits are based many factors such as location, type of treatment available at POTW, type of discharge (river, municipality, land application, etc.).
TABLE 1: Compiled profile of wastewater from conventional
(non-mechanized) blue crab processing.
Parameter |
Flow
Gal water/kg product |
pH |
TSS
(mg/L) |
FOG
(mg/L) |
BOD5
(mg/L) |
COD
(mg/L) |
TKN
(mg/L) |
Total
Phosphorus
(mg/L) |
Total
Sodium
(mg/L) |
Values |
3.0-10.0 |
6.0-8.5 |
310- 620 |
160 -280 |
3,200 - 5,300 |
4,600– 7,900 |
100-300 |
0-80 |
100-300 |
TSS – Total Suspended Solids
FOG – Fat, Oil and Grease
BOD5 – A five day Biochemical Oxygen Demand
COD – Chemical Oxygen Demand
TKN – Total Kjeldahl Nitrogen
Other Resources
Sustainability Resources for Seafood
Food Processing Environmental Assistance Center
Purdue University, Food Science Building, 745 Agriculture Mall Drive, West Lafayette, IN 47906
Phone: 765-494-7997 • FAX: 765-494-7953
Disclaimer | About | Contact | Home
|
