Shrimp and Prawn Processing Wastewater Treatment: Heads, Peel and Brine

Shrimp and prawn processing makes water that is strong, smelly and sometimes salty. Heading and peeling release heads, shells and soluble protein, and the chilling and washing steps add brine from the ice and the salt used to keep the catch fresh. The organic load is high and putrescible, so the water turns sour fast, and the salinity complicates both biology and any reuse. Treat it as a strong, smelly, sometimes-saline protein stream and move it quickly.

A Putrescible Protein Stream

Heads and peel are the first load. They are mostly soluble protein and chitin, and they degrade fast, which means a tank that is not turned over becomes a smell and a compliance problem within a day.

Brine from chilling and washing is the salinity source. High salinity inhibits ordinary biomass and constrains reuse, so keeping the brine streams separate from the process water is worth real effort.

Chitin from shells is a solid that settles poorly and can be recovered, but on most lines it is simply a suspended solids load the treatment plant has to handle. Much of this mirrors the situation set out in Oleochemical Plant Wastewater Treatment.

Catch is seasonal and the plant runs hard when the boats land. The load follows the catch, not the calendar, and the equalisation volume has to absorb that. The process logic sits close to what is described in APT and Ammonia, particularly on the pretreatment side.

Heads, Peel and Soluble Protein

Soluble protein from heads and peeling is the bulk of the BOD, and because it is soluble it passes every screen. Coagulation with a cheap inorganic salt pulls much of it out before biology, and that is the standard first move.

Recovering protein as a feed-grade product is worth considering on large lines, because what you recover upstream is load you do not pay to treat downstream.

Because the protein is putrescible, holding time is the enemy. Short retention, good mixing and prompt treatment beat a big lazy tank on this duty.

Do not let a protein slug reach the anaerobic digester unmanaged. A concentrated slug will acidify and sour a digester faster than most other food streams.

Brine and the Salt Balance

Brine from chilling is the salinity source. Keep it separate so the fresh process water can be treated biologically, and decide early what you will do with the salt stream rather than mixing it in by default.

Diluting a high-salinity brine into a biological effluent salts the biomass and degrades the whole works, so keep it out of the biology.

Where the brine is sent to a permitted industrial drain, the salt load is what the utility charges for, so it is a direct and ongoing cost, not a free disposal.

Some sites recover salt or reuse brine for washing, and the cheaper long-term move on a steady line is to concentrate and recover rather than discharge.

The stream varies in strength by the hour as lines start and stop. A mixed, buffered equalisation tank is what lets the biological stage run steady.

At the loads a shrimp plant reaches, anaerobic digestion ahead of aerobic recovers energy as biogas and shrinks the aerated stage. The gas offsets a real part of the plant energy bill.

The aerobic polish removes residual BOD and nitrogen. It is smaller than it would be without the anaerobic front end, which is the whole point on a high-strength food effluent.

Reference Data from 42 Commissioned Plants

Across 42 commissioned plants where we hold complete COD records, influent COD ranged from 200 to 172,000 mg/L and treated effluent from 50 to 5,000 mg/L. Average removal across that set is 87.1% — not a marketing figure, but the measured mean.

That average is worth pausing on. It sits well below the 95%-plus numbers most suppliers quote, because the set includes genuinely difficult streams. On some electroplating and municipal duties the installed configuration only reaches about half the influent COD, and saying that up front is more use to you than a number the plant will never hold.

Sludge is organic and settles poorly when loaded with fine protein and shell. Dewatering needs to be specified for that, not for a municipal sludge.

Operating Notes

Recover protein where volumes justify it. This is a stream where upstream recovery pays for itself in reduced treatment load. Where several streams need joint treatment, Battery Materials Recovery is the more detailed reference.

Keep brine separate from the process water. Mixing salt in by default just makes biology harder and reuse impossible.

Finally, turn the water over fast. Shrimp effluent sours within a day, so short retention and prompt treatment beat a large idle tank.

Why Choose Baihuipu as Your Manufacturer

Picking a supplier for this kind of plant is mostly about who carries the risk when something goes wrong. We have built this equipment for more than twenty years, and we are the ones who fabricated it, programmed the controls and will still answer the phone three years from now.

Manufacturing Base in Guangdong

Owned production lines mean we control tolerances, materials and delivery. Standard modular units and bespoke skids are both built by our own people, so schedule commitments are ours to keep.

Two Decades of Field Data

Food and beverage, chemicals, electroplating, textile dyeing, mining, municipal work — we have commissioned across all of them. The useful part is not the project count, it is having seen how plants fail in year seven and designing those failures out.

Complete Units and Turnkey Plants

Whether you need a single package unit or a turnkey installation with civil works, we deliver the entire treatment scheme. Our engineering team covers process, mechanical, electrical and automation so one party owns the outcome.

Spares, Service and Commissioning

Membranes, dosing pumps, diffusers, instrumentation and blowers are stocked for the systems we sell. Our control systems support remote diagnostics, and we can put an engineer on site for commissioning, training or an unplanned shutdown.

Talk to Our Engineers

Send through your raw water data and we will advise on the viable process route and realistic operating cost before you commit to anything. We can be reached on WhatsApp: +86 13631765076 or through hkbhp.com.

WhatsApp: +86 13631765076

Frequently Asked Questions

What spare parts should we hold on site?

Critical spares are pumps, dosing valves, instrumentation sensors and any specialty media. We ship a recommended spares kit with the plant and hold stock for everything we supply, so lead times on replacements stay short.

What happens if the incoming shrimp prawn processing load exceeds the design figure?

Load swings are the most common reason plants underperform. We set the design envelope from your worst-case samples, not your average ones, and specify enough buffer in the biological stage to ride out shocks. If your process genuinely shifts up permanently, we can usually add capacity in stages.

Do you export and support overseas installations?

We have shipped to the USA, Canada, Indonesia, India, Russia, Vietnam and Nigeria among others. Documentation, crating and export paperwork are handled in-house, and we support commissioning either remotely or with engineers on site.

What information do you need to quote?

Water analysis for your worst-case stream, peak and average flows, discharge limits, available footprint and utilities. If you do not have a full analysis yet, we can start from a partial one and flag the gaps.