Seafood Processing Plant in Dong Nai Province, Vietnam

Project Background

This plant primarily processes pangasius (basa) fish, generating about 800 m³/day of wastewater. The original treatment system used a facultative + aerobic process, but COD and ammonia nitrogen removal were unstable, especially during the peak season (September to December) when loads surged. Vietnam’s environmental authorities required all food processing industries to meet Class A discharge standards (COD < 75 mg/L, ammonia nitrogen < 5 mg/L) by the end of 2023.

MBBR Retrofit Solution

MBBR Media was integrated directly into the existing aerobic tank at a 40% filling ratio, with no new tanks required. The aeration system was upgraded to fine‑bubble diffusers to enhance oxygen transfer efficiency.

Retrofit Results

● COD reduced from 850‑1,200 mg/L to an average of 62 mg/L, removal efficiency 94% .

● Ammonia nitrogen reduced from 120 mg/L to 4.5 mg/L, removal efficiency 96%.

● Shock load resistance significantly improved; effluent remained stable even during peak season.

● Sludge production decreased by about 60%, greatly reducing sludge disposal costs.

● Retrofit investment payback period only 14 months.