Biogas generate electricity

Anaerobic fermentation of livestock excrements generates biogas, of which more than 60% is methane, a greenhouse gas. According to the IPCC 2007 report, the potential of methane to cause greenhouse effect and global warming is 25 times than that of carbon dioxide.

Therefore, collecting and utilizing biogas not only reduce greenhouse gas emissions but can also serve as a more stable source of bioenergy. After different levels of purification and recovery, biogas can be used for electricity generation, heating, and vehicle fuel.

Liquor and fiber digestate

Livestock excrements, after anaerobic digestion, would generate a water-soluble substance called "liquor digestate," and solid by-product called "fiber digestate." Both liquor and fiber digestate contain abundant nutrients and fertilizers that can be absorbed by crops and increase their yield.

Furthermore, research shows that the nitrogen fertilizer obtained from raising pigs in a year is equivalent to one bag of fertilizer #5 of Taiwan Fertilizer Company. Farmers can use liquor and fiber digestate to reduce the use of chemical fertilizers, promote organic farming, and save a significant amount of expense on fertilizer.

The recycling and reuse of animal excreta from livestock farming

Based on the Agriculture Industrial Waste Reuse Management Regulations, the Council of Agriculture, Executive Yuan, encouraged livestock farmers to collect livestock excrements in barrels or tank trucks and transport them outside the farmland for further processing, and the wastewater was used to restore farmlands after treatment. From 2009 to 2010, a pilot project was conducted to transport pig wastewater for irrigation, and the report indicated no negative impact on soil, groundwater, or public health. Therefore, proposals to reuse agricultural waste could now be accepted so to attain to advantages such as saving irrigation water, supplementing nitrogen fertilizer, and reducing carbon emissions.

Discharge for irrigation in plantation

Due to the scarcity of global water resources, recovery of wastewater has become a worldwide trend. Taiwan, constrained by its geographical environment and climate, is ranked as the 18th among countries with water scarcity in the world.

The livestock farming industry is often located in rural areas and developed alongside agriculture and fisheries. Given that the livestock excrement is naturally high in organic and nitrogenous substances, if it meets the effluent standards after treatment, it could provide the water and nutrients needed for crops, and reduce groundwater extraction and the demand for agricultural irrigation and drainage. This creates a multi-win situation for the livestock industry, farmers, and the water environment.