Noon Sugar Mills Limited, Bhalwal, Sargodha, Pakistan

Distillery Wastewater Anaerobic Treatment System

Noon Sugar Mills Ltd. (NSM), one of the largest sugar units in Bhalwal, Sargodha, Pakistan operates a 50 KL per day capacity distillery. The wastewater (spent wash) contains a very high BOD and COD.

Noon Sugar Mills chose a Low Rate Anaerobic Digester System for the anaerobic treatment of its spent wash to reduce most of the biodegradable organic matter and generate large quantities of methane-rich biogas. The biogas generated in the digester was to be used as alternative fuel in the plant boiler to produce steam.

The Anaerobic Digester System is designed for a 700 M3/day spent wash flow with a BOD of 40,000 mg/l and a COD of 80,000 mg/l. The system is designed to achieve a 90% reduction in BOD and a 70% reduction in COD. The expected biogas generation is approximately 20,000 M3/day with a calorific value of about 5,000 KCal/M3. The system consists of two steel digesters each of 10,600 M3 volume, operating in a parallel mode. These digesters are equipped with a Floating Geo-membrane Cover system. The biogas is collected from under the membrane covers and delivered to boilers to produce steam. This installation was completed in April, 1999 and has been producing satisfactory results since.