Taking the next step forward in enhancing the value of constructed wetlands, a pilot biogas plant to extract energy from the biomass of constructed wetlands was installed on ICRISAT campus recently.
Several tons of biomass from constructed wetlands needs to be disposed periodically either through composting or through biogas/biofuel production. Some of the biomass varieties grown on constructed wetlands, such as Typha latifolia have very high productivity (~35kg/m2) and also high biogas potential (~200m3/t) and are better suited for energy production than composting.
The plant will help dispose plant biomass from wetlands, agricultural residues and food wastes generated on campus in an environment friendly manner while producing a clean and renewable form of energy which can be used for cooking. Furthermore, the slurry output of the biogas plant (approx. 200 liters per day) can be directly applied to the agricultural fields as a liquid biofertilizer as it contains nutrients and minerals that can be more readily absorbed by plants and thus serves as an efficient soil-improvement medium.
Use of untreated domestic and industrial wastewater for agriculture is a significant problem. It results in degraded soils due to accumulation of salts and heavy metals thus making them unfit for agriculture and also posing a serious health hazard to consumers. Constructed wetlands help tackle the problem by making the water fit for use in agriculture. This also helps augment the supply of water for agriculture, potentially reducing the overexploitation of groundwater in agriculture. The safe reuse of wastewater for agricultural purposes shows higher crop yields and helps reduce the amount of pollutants in wastewater by 30-92%.
“It is very important to keep the nutrient cycle closed for the benefit of the environment and agriculture. This goal can be clearly achieved with the help of innovative initiatives such as a biogas plant to recycle the biomass generated on constructed wetlands and again using the energy for cooking and putting the slurry back into agriculture which aids in efficient distribution and closure of nutrient cycle,” said Dr Chandra Madramootoo, ICRISAT Governing Board Chair, at the inauguration of the plant.
“This is a great example of innovative partnerships between ICRISAT and a private company. Such partnerships are needed to strengthen ICRISAT’s research capacity towards innovative ideas for sustainable and reliable solutions in agriculture and environment. Producing biogas from organic wastes and cooking food using biogas means that we can have clean energy, cleaner homes and thus a cleaner environment,” said Dr David Bergvinson, Director General, ICRISAT.
“The biogas plant will be utilized to process up to 100 kg of organic biomass/wastes generated on campus and can produce about 15 m3 of biogas per day,” said Dr Wani, Director, ICRISAT Development Center (IDC) and Research Program Director, Asia. The plant has been established by IDC as part of the Indo-EU Water4Crops (www.water4crops.org) project. Water4Crops is one of the largest EU-India collaborative projects that aims to address the problems of using untreated domestic and industrial wastewaters for agriculture.
The plant, designed and fabricated by Xeon Waste Managers, Pune, Maharashtra, was inaugurated on 17 February.