Fonterra Dairy, Tirau
Methane (bio-gas) generated from the site's anaerobic waste water treatment pond is used to partially fuel the site's boilers. Fonterra Tirau has one of the biggest waste water treatment plants in the Southern Hemisphere and supports other sites in the region.
This bioenergy process was novel in the dairy industry at this scale in 1983. The process, producing both energy and a very high standard of treatment, has provided significant economic and environmental benefits for over 22 years, enabling this dairy-processing site to remain viable.
The capacity of the plant is 70 tonnes of chemical oxygen demand per day and wastewater flow of 3 million litres per day. The plant was one of the largest anaerobic plants for industrial wastes in the world and was in 1984, the first full-scale anaerobic plant for the treatment of dairy wastes.
Fonterra Tirau, removes sludge from anaerobic lagoon annually and is applied mainly to maize cropping land. Lime
is dosed to the anaerobic process for pH control and to remove Phosphorus, so sludge has high content of lime and