Petrochemical Plant in Jubail, Saudi Arabia

Project Background

The original wastewater treatment system at this petrochemical plant had a design capacity of 10,000 m³/day. However, due to capacity expansion, both influent flow and pollutant loads exceeded design values. The wastewater contained high concentrations of recalcitrant organics such as benzene series and phenols. The conventional activated sludge system had low treatment efficiency and suffered from frequent sludge bulking. The plant required a capacity increase and stability improvement without expanding the footprint.

MBBR Retrofit Solution

The existing aeration tank was converted into a two‑stage series MBBR system. The first stage primarily removed easily biodegradable organics (BOD/COD), while the second stage targeted recalcitrant compounds and ammonia nitrogen. Our MBBR Media (Φ25 mm) was used at a total filling ratio of 55%. The inherent fixed‑film nature of the MBBR system provided much higher tolerance to toxic substances compared to suspended growth systems.

Retrofit Results

● Treatment capacity increased by 40%, meeting post‑expansion demand.

● COD removal efficiency improved from 78% to 92%.

● Sludge bulking completely resolved (MBBR systems require no sludge return and do not suffer from bulking) .

● Operational stability greatly improved; effluent remained compliant even during influent fluctuations.

● Annual operating costs reduced by approximately USD 350,000.