Future proofing our wastewater treatment infrastructure

Fossil fuel and electricity costs could significantly increase in the not too far future. This will affect our industrial sector and waste treatment service providers who are exposed to price changes as they maintain wastewater treatment plants with significant use of electricity. CPG was commissioned in 2007 to estimate the present and future New Zealand biofuel production potential to produce additional biogas fuel via treatment of industrial and primary processing byproducts by anaerobic digestion. The data showed that only about 25 % of the biogas production potential from these materials is currently realized (0.45 PJ biogas /annum). Co-digestion of suitable and available industrial, commercial and institutional sludge materials with the municipal WWTP biosolids in urban environments would produce additionally 0.45 PJ biogas/annum and double the biogas potential to approximately 0.9 PJ biogas/annum. Nationwide systematic capture of wastewater treatment dissolved air floatation (DAF) sludge material from meat processing and dairy factories could quadruple the potential to approximately 1.9 PJ biogas/annum. We compare in this paper the technical and commercial feasibility and advantages/disadvantages of implementing new co-digestion facilities through upgrade of existing municipal digesters or through new construction of dedicated anaerobic digestion facilities next to large industrial energy users.