The development of a biogas production system from pig manure for environmentally friendly

           Walailak demonstration community, Thasala District, Nakhon Si Thammarat Province, is an ideal surrounding community of Walailak University. People in the community have an additional economic improvement profession which is pig farming. The environmental impact of pig farming is mainly driven by the spread of feces and waste to surrounding neighborhoods, polluting air, and water with toxic waste particles. Waste from pig farms can carry pathogens, bacteria (often antibiotic-resistant), and heavy metals that can be toxic when ingested. Pig waste also contributes to groundwater pollution in the forms of groundwater seepage and waste spray into neighboring areas with sprinklers. The change of pig manure to energy by converted to biogas is an environmentally friendly and good waste management solution.

        From the social engagement project 2020, the sample pig farm at Walailak demonstration community has installed and operated biogas production from pig manure by using a semi-continuous digester because the continuous digestion process bacteria are more tolerant of changes in environmental conditions than those of the batch digestion process.  Normally an adult pig produces around 5kg of manure every day. This waste is 90% water and 7% volatile solids, which can produce 0.136 cubic meters (4.8 cubic feet) of biogas daily. There are 12 adult pigs at the farm so this process can produce 1.63 cubic meters of biogas daily. However, the installed reactor has a daily wastewater capacity less than 10 kg/day. Therefore, this system cannot support the total amount of wastewater generated per day of this pig farm. 

          To solve the problem, The purpose of this project was to develop a biogas production system from pig manure. The low-cost plastic biogasters was used in the project. “The development of a biogas production system from pig manure for environmentally friendly” was held during 1 October 2020 – 30 September 2021. The experimental of this project divided into 2 parts. The first part is designed and build the continuous biogas production system. The other is on-site testing and weekly follow-up of the biogas system. The results show that the low-cost plastic biogasters can produce biogas about 1.61-2.81 m3/day or 84.28 m3/month. The generated biogas can be used as a substitute for household cooking gas, resulting in a reduction in household expenditure by approximately 1000 baht per month or equal to the cost of purchasing 2.5 cooking tank (15 kg). Moreover, the sludge that overflows from the biogas digester can be used as fertilizer for plants and vegetable gardens as well (Saving on fertilizer about 200-500 baht per month). Moreover, the resulting biogas can be utilized in a variety of ways, such as centralized heating systems, pipe connection to distribute applications within the community nearby the farm or using biogas to generate electricity for use within the farm.

          Moreover, the project of “the development of a biogas production system from pig manure for environmentally friendly” ​ was helping to achieve the Sustainable Development Goals (SDGs) in the areas of 

• wastewater treatment :The biogas system in this project reduce chemical oxygen demand of pig farm wastewater by approximately 80%, reducing the risk of water contamination. Helps to achieve SDG 6 clean water and sanitation (Ensure availability and sustainable management of water and sanitation for all).
• Renewable energy: Biogas is a flexible fuel. It can used to reduce liquid propane gas’ fee for over 1000 Bath/month/household. Helps to achieve SDG 7 affordable and clean energy (Ensure access to affordable, reliable, sustainable and modern energy for all).
• Consumption and Production: this project treats waste at the source and produces clean energy using proven technology. Reducing pollution, controlling polluted water and waste from pig farms. Receiving fertilizer from animal manures. Helps to achieve SDG 12 responsible consumption and production (Ensure sustainable consumption and production patterns).
• Other Sustainable Development Goals: In addition, our biogas systems make a positive contribution to SDG goals 2 (End hunger, achieve food security and improved nutrition and promote sustainable agriculture) fertilizer that by-product from biogas production helps increasing crop yields through the use of nutrient-rich digestate biofertilizer and SDG goals  3 (Ensure healthy lives and promote well-being for all at all ages) treating and recycling organic wastes  (pig manure) to reduce odors and the spread of diseases.