Bio Digester System Overview of Experience and Cost Benefit Analysis

Where is it installed? Mara Plains Camp Olare-Motorogi Conservancy

Why was it installed? To deal with waste! Gold Eco- Rating Very low lying area in black cotton soil, so no other real options.

Cost Benefit Analysis Costs Purchase and Installation 2,500,000 Annual Maintenance Contract 50,000 Other Annual Costs - Samples 16,000 Benefits (per Annum) Monthly removal of Sewage per load) 240,000 Recycled Water Used (approximately 3000 litres per month, 1/- per litre) 36,000 Annual Benefit less Annual Costs 210,000 Straight Payback - Years 11.9

Cost Benefit Analysis Intangible Benefits (per Annum) Gold Eco-Rating 1,000,000 No Smells 500,000 NEMA Compliance ?? Annual Benefit less Annual Costs 1,710,000 Straight Payback - Years 1.5

Other Pros and Cons Biobox BioRock® System Pros No moving parts No pumps and motors No Power Consumption Low Maintenance, Local Support Should last 25 years

Other Pros and Cons Cons Teething problems, slight smells etc The system is good, but only as good as the installation. The flow rates need to be balanced and correct. Laundry and Detergents Upset the Balance Grease Traps for Kitchen Waste – need to be kept clean