Why Aquaculture Effluent Is a Growing EPC Challenge

Indonesia and Vietnam together produce more than 1.1 million metric tons of farmed shrimp per year, supplying over 25% of global demand. Intensification of vannamei (white-leg shrimp) ponds has driven a parallel surge in high-strength saline wastewater loaded with feed residues, ammonia, nitrite, total suspended solids (TSS) and disease pathogens such as Vibrio and white spot virus. Discharging this effluent untreated damages coastal mangroves, triggers regulatory shutdowns, and exposes farm operators to export-market residue audits.

For EPC contractors, the opportunity is clear: build modular, pre-commissioned treatment trains that turn pond drain water into reusable process water, cutting both freshwater intake and discharge penalties. The two workhorse technologies that make this possible are Dissolved Air Flotation (DAF) for solids/fine-solids removal and closed-loop recirculation with biofiltration or MBR polishing.

Process Flow: From Pond Drain to Reusable Process Water

1. Pre-screening: Rotary drum or bar screen (1–3 mm) to remove feed pellets, molts and macro-solids.
2. Lift pump station: Submersible corrosion-resistant pumps (typically duplex, with standby) feeding the DAF unit at controlled flow.
3. DAF clarification: 5–25 m³/h units, 4–6 bar saturator, 10–25% recycle ratio, polymer dosing for colloidal solids.
4. Biofilter or MBR: Ammonia/nitrite oxidation; MBR variants deliver sub-1 NTU effluent for full recirculation.
5. Disinfection: UV or ozone polishing to control pathogens before pond reuse or discharge.
6. Sludge handling: DAF float thickened to 4–6% DS, then dewatered by volute screw press for off-site disposal or composting.

Technical Comparison: DAF Alone vs DAF + Recirculation

Parameter	DAF Only (Discharge Path)	DAF + Recirculation (Reuse Path)
Effluent TSS	20–50 mg/L	< 5 mg/L (after MBR)
Ammonia nitrogen	Unchanged	< 1 mg/L (after biofilter/MBR)
Freshwater intake	100% make-up	40–70% reduction
Discharge compliance	Meets basic standards	Exceeds recirculation-ready limits
Pathogen control	Limited	UV/ozone integrated
Typical CAPEX (5 m³/h)	USD 35–55k	USD 90–140k
OPEX savings (5-yr)	Baseline	30–50% on water + discharge fees

Regional Market Analysis

Indonesia

Indonesian shrimp production is concentrated in Lampung, Banyuwangi, Situbondo and South Sulawesi. The Ministry of Marine Affairs and Fisheries (KKP) and KLHK are tightening brackish-water discharge limits, with new Marine Environment Quality Standards expected in 2026. Many large farms (e.g., CP Prima, Central Proteinaprima) are now requiring turnkey treatment skids from EPC contractors. Salinity (15–30 ppt) demands duplex stainless or FRP construction for all DAF and piping components.

Vietnam

The Mekong Delta provinces of Cá Mau, Sóc Trăng and Bạc Liêu account for 70% of Vietnam’s shrimp output. Decree 08/2022/ND-CP and provincial DOST guidelines now require effluent recirculation or zero-discharge targets for new intensive ponds. Vietnamese EPCs favor containerized DAF + MBR packages that can be shipped by barge to remote coastal sites and commissioned in under 14 days.

Recommended Specification for EPC Procurement

• DAF hydraulic capacity: sized at 0.8–1.2× daily pond drain flow.
• Construction: SS316L or fiberglass-reinforced plastic (FRP) for saltwater resistance.
• Saturator: 4–6 bar, 10–30% recycle, automatic air/water ratio control.
• Sludge handling: integrated volute screw press, 4–6% DS concentrate, 75–80% recovery.
• Biofilter/MBR: surface area sized at 0.15–0.25 m²/kg BOD-day; MBR option for full recirculation.
• Disinfection: UV dose ≥ 40 mJ/cm² or ozone residual 0.2–0.5 mg/L.
• Controls: PLC with HMI, optional 4G telemetry for remote farms.

Bottom Line

Shrimp farm wastewater is moving from “out of sight, out of mind” to a regulated, auditable process stream. EPC contractors that master the DAF + recirculation playbook today will be first in line for the next wave of intensive aquaculture projects in Indonesia and Vietnam. The combination of stricter regulations, water scarcity and export compliance makes this one of the highest-growth water-treatment verticals in Southeast Asia.

Designing a shrimp-farm treatment train for an Indonesian or Vietnamese project? Talk to our aquaculture wastewater team for a tailored DAF + screw press + MBR sizing proposal and reference projects.