Energy-Positive Wastewater Treatment and Reuse System For Agriculture Applications

The use of recycled water has never been more important than it is today, especially with California and the Western United States experiencing the worst drought in 500 years.To address the severe and persistent shortage of water,growers in California are increasingly looking to recycled water as a way to consistently meet their irrigation demands. The main challenge for water reuse in agriculture remains in finding cheap and appropriate wastewater treatment systems that can improve the quality of wastewater used in irrigation without imposing risks on health or the environment.Methane is both a potent greenhouse gas and a valuable source of energy. The methane potential from animal manure in the United States is estimated at about 257 billion cubic feet or 142 trillion British thermal units, which is about 40% of total estimated energy potential from biogas sources in the U.S.[7] This is enough energy to power more than 1.2 million U.S. homes for one year or to produce the equivalent of 1 billion gallons of gasoline for vehicles. In March 2014, the White House released the Climate Action Plan - Strategy to Reduce Methane Emissions in which USDA, EPA and DOE identified strategies to reduce methane emission through the use of biogas systems and overcome barriers to a robust biogas industry in the United States. It supports the U.S. dairy industry's voluntary 2008 goal to reduce its greenhouse gas emissions by 25% by 2020.In order to develop an enhanced solution for improving agriculture water reuse while maximizing biogas energy recovery, Cambrian Innovation proposes a packaged, distributed, energy-positive wastewater treatment and reuse system (WTRS) targeted for manure wastewater which will enable more than 70% wastewater reuse by utilizing a combination of a novel anaerobic solids digester and membrane bioreactor (MBR). This system will be capable of addressing the major limitations associated with existing AD systems for manure waste treatment, while providing additional benefits as follows: (i) capability to reuse 70% of wastewater; (ii) energy-positive system; (iii) minimal waste generation; and (iv) modular design. Phase I R&D will focus on validating the proof of concept of the proposed integrated upflow anaerobic solids and liquid (UASL) digester, as the MBR is a mature technology.The successful development of this novel technology will significantly mitigate water pollution and supplement water supplies for agriculture applications while maximizing energy recovery via biogas production.