Proceedings

The Cambi thermal hydrolysis process (THP) has been operated on full-scale projects in the range of 1,000 to 35,000 dry tonnes of sludge per year. Since the fall of 1995 ten plants have been built and all are operating well. Three more are in construction. The basis of Cambi technology is to pressure cook sludge cake at about 6 Bar (165C) for about 30 minutes as a pre-treatment for anaerobic digestion.

The following benefits can be achieved:

• more biogas production – typically 60% VS reduction
• biosolids mass reduction, typically digested cake at >30% DS
• enhanced digester capacity – digester loading of 5-6 kg VS/m3 per day
• fully pasteurised product – free of all know pathogens
• very stable digestion operations – high digesting biomass and consistent feed.
• a very compact and automatic plant, typically half the volume of conventional digestion

The thermal hydrolysis plants have been easily integrated into existing and new sludge treatment plants. Each plant is optimized to achieve the lowest possible processing costs. There have been a number of new challenges on each project but Cambi has overcome these so that all plants are running well.

KEY WORDS: Biosolids, Cambi, Plants, Case Studies Digestion, Sewage Sludge, Thermal Hydrolysis Volatile Destruction.