Greenhouse gas emission reduction and environmental quality improvement from implementation of aerobic waste treatment systems in swine farms

摘要

Trading of greenhouse gas (GHG) emission reductions is an attractive approach to help producers implement cleaner treatment technologies to replace current anaerobic lagoons. Our objectives were to estimate greenhouse gas (GHG) emission reductions from implementation of aerobic technology in USA swine farms. Emission reductions were calculated using the approved United Nations framework convention on climate change (UNFCCC) methodology in conjunction with monitoring information collected during full-scale demonstration of the new treatment system in a 4360-head swine operation in North Carolina (USA). Emission sources for the project and baseline manure management system were methane (CH_4) emissions from the decomposition of manure under anaerobic conditions and nitrous oxide (N_2O) emissions during storage and handling of manure in the manure management system. Emission reductions resulted from the difference between total project and baseline emissions. The project activity included an on-farm wastewater treatment system consisting of liquid-solid separation, treatment of the separated liquid using aerobic biological N removal, chemical disinfection and soluble P removal using lime. The project activity was completed with a centralized facility that used aerobic composting to process the separated solids. Replacement of the lagoon technology with the cleaner aerobic technology reduced GHG emissions 96.9%, from 4972 tonnes of carbon dioxide equivalents (CO_2-eq) to 153 tonnes CO_2-eq/year. Total net emission reductions by the project activity in the 4360-head finishing operation were 4776.6 tonnes CO_2-eq per year or 1.10 tonnes CO_2-eq/head per year. The dollar value from implementation of this project in this swine farm was US$19,106/year using current Chicago Climate Exchange trading values of US$4/t CO_2. This translates into a direct economic benefit to the producer of US$1.75 per finished pig. Thus, GHG emission reductions and credits can help compensate for the higher installation cost of cleaner aerobic technologies and facilitate producer adoption of environmentally superior technologies to replace current anaerobic lagoons in the USA.