Company ProfileCase Study: Sugar Alcohol Distillery—Sao Paulo, Brazil
The Problem
A sugar alcohol distillery near Sao Paulo was discharging approximately 4,400 m³/day of distillery slop at a COD of 54,500 mg/l into lagoons and then, without any appreciable reduction in COD levels, directly into the Piricicaba River. As a result, the Piricicaba River had a COD level of over 1,000 mg/l. This pollution load needed to be drastically reduced. Additionally, a local source of energy was needed.The EversTech Solution
CSR and EversTech decided to treat the distillery slop with EversTech's ET Process. An aerobic stage was added to the basic process. Bio-augmentation of the thermophilic anaerobic digester, to enhance biogas production for ultimate steam raising and energy generation, was also incorporated into the treatment.
The gas burned in a boiler generates approximately 20.5 tons/hour steam at 300°C and 350 psi pressure, which in turn gives 1,800 kilowatts continuous electricity and 20.5 tonnes/hour saturated steam at 35 psi for distillery process. The separated lignin prior to digestion generates an additional 13 tons/hour of steam under the same conditions, and 1,150 kilowatts of continuous electricity.
The cake produced by centrifuging of the excess activated sludge can also be burned after drying in drying beds, which will provide 6.8 tons/hour steam and 600 kws. continuous electricity, making the total energy produced 3,550 kws. of continuous electricity and 40.3 tons/hour saturated steam at 35 psi pressure. The biomass cake could also be used in the cane fields, or marketed as an organic fertilizer.
The final effluent quality which was discharged into the lagoons was 4,000 m3/day with COD of 600 mg/l, BOD of 200 mg/l and SS of 50 mg/l.