Anaerobic digestion has become an increasingly popular technology for treating wastewater. UEM specializes in design and construction of anaerobic wastewater treatment plants on turnkey basis. UEM has installed more than 60 low rate anaerobic digester systems for various industries such as distilleries, breweries, pharmaceuticals, pulp & paper, citric acid, yeast, chemicals, etc. These digesters provide a large volume (hydraulic retention time: 15- 45 days), offering better process stability with consistent performance and biogas generation. BOD reductions of 80%- 95% and COD reductions 60% – 80% can be achieved, depending on the nature of the wastewater. These digesters can be constructed in a rectangular or circular above ground or below ground construction.
In absence of oxygen i.e. under anaerobic environment, bacteria decompose organic pollutants (BOD, COD, etc.) to carbon dioxide, methane and water. The biogas here is generated through a series of biomethanisation reactions. The large quantities of biogas generated have been used to replace fuel in boilers and to generate electricity in generators, offering quick returns to our clients. Benefits of this anaerobic system includes high reductions in organic load and thus less loading and power consumption in the downstream treatment process. In addition, the use of biogas as a renewable non-conventional source of energy is possible.
Due to the environmental benefits of anaerobic digestion, UEM has been able to secure grants and funding for some of our anaerobic digestion projects. These grants and funding opportunities can offset the cost of the anaerobic treatment system, further improving the economics of using anaerobic treatment. Additional streams of revenue in the form of carbon credits can also be secured which can allow for a design-build-finance-operate form of project delivery – UEM recently executed a project that was delivered in this manner.
For the project Bioenergia in Guatemala, UEM has installed the anaerobic digesters for the treatment of alcohol distillery wastewater. The rich organic matter in wastewater (vinasse or spentwash) is converted into rich biogas i.e. methane which is used as fuel in the distillery to produce steam. Biogas generation replaced approximately 2,363,300 gallons of fossil fuels per year and also reducing the methane emissions. Use of biogas instead of fossil fuel helped in reduction of about 43,889 tons of CO2 emissions annually. Due to this, carbon credits were able to be secured under the Clean Development Mechanism (CDM). UEM is a member of Bioenergia S.A. which is the Guatemalan registered company created by CAREC, E+Co, UEM Group, and SEMA for the purpose of designing, building, owning and operating the Anaerobic Digestion biogas plant system.