Vermicomposting and Land Utilisation of Biosolids With Pulpmill Solids

New Zealand's central north island economy is dominated by intensive dairy farming and forestry operations. The soils are young, porous, shallow, and are lacking of soil humus. To mitigate nutrient losses, farmers are increasingly opting to replace mineral fertilisers with humus rich organic fertilisers. The region is producing approximately 50,000 tonnes of biosolids and 200,000 tonnes of carbon rich fibrous by-products from pulp and paper mills per year. Until recently, these had been sent to landfills with dramatic negative effects on New Zealand greenhouse gas emission balance. From 2007 these waste streams have been blended and processed in industrial scale vermicomposting operations established within the region. In 2013, greater than 100,000 tonnes of organic wastes have been vermicomposted including 35,196 tonnes of municipal biosolids and 68,746 tonnes of pulp mill solids. From this approximately 30,000 tonnes of vermicast has been produced and has been land applied. The local vermicomposting industry is currently establishing its third industrial vermicomposting operation in the North Island to process 150,000 tonnes per year and positions New Zealand as the global leader in vermicomposting technologies.