Olive Oil Mill in Andalusia, Spain

Project Background

Olive mill wastewater (known as “alpechín”) is one of the most difficult industrial wastewaters to treat. It contains high concentrations of phenolic compounds, organic matter, and fats, with COD levels reaching as high as 200,000 mg/L or more. This facility processes about 30,000 tons of olives annually, generating roughly 200 m³/day of wastewater during the production season (November to February). The original system achieved a COD removal efficiency of less than 60%.

MBBR Retrofit Solution

A two‑stage anaerobic + aerobic MBBR process was adopted. The anaerobic stage significantly reduced the organic load, while the aerobic MBBR provided advanced treatment. The aerobic MBBR used our specially formulated MBBR Media with high salt tolerance and toxicity resistance at a 45% filling ratio.

Retrofit Results

● Overall COD removal efficiency reached 97% (from a peak of 120,000 mg/L to below 3,000 mg/L).

● Phenol removal efficiency 99%.

● The system can run at low load during the off‑season and quickly recover during the production season, adapting to seasonal operation.

● Treatment costs reduced by 40% compared to conventional solutions.