Continuous treatment of industrial dairy effluent by electrocoagulation using aluminum electrodes

Abstract

Electrocoagulation is one of the most efficient and convenient techniques for the elimination of several types of pollutants. Its efficiency has been validated for numerous industrial effluents (food, mechanical, textiles, paper industries, etc.). This paper deals with the treatment of dairy wastewater in Algeria by electrocoagulation using aluminum electrodes. The experiments were conducted in a small continuous reactor at laboratory scale. Turbidity and chemical oxygen demand (COD) were followed continuously during the startup period and at steady-state, where as BOD₅ (five-day biological oxygen demand), greases, and phosphorus were analyzed punctually at steady state using the better operating conditions. The effect of operational parameters, such as current density, initial pH, inlet flow rate, and the temperature of waste water, were examined to optimize the effectiveness of the treatment. A satisfactory reduction of 98% of the turbidity and 90% of the COD were obtained for the optimal conditions. The abatements of BOD₅ and greases were close to 97%, whereas 70% of the phosphorus was eliminated. Treatment of industrial wastewater concentrated with several milk powder concentrations has been also analyzed. Reasonable energy consumption of around 2 to 3.5 kWh/m³ for adequate operating conditions validates the economic reliability of this choice of treatment.

Keywords:

• Dairy effluent
• Turbidity
• Aluminum electrodes
• Continuous reactor