Anaerobic wastewater treatment and biogas production from brewery effluent

June 1, 2018

In this case study, a global beer producer — set to begin production in a new brewery — works proactively with the local wastewater treatment plant to install an anaerobic wastewater pretreatment facility.

In 2019, MolsonCoors, a 230-year-old beermaker with 18,000 employees at 31 breweries selling product in more than 50 countries, is scheduled to start production in its new state-of-the-art brewery in Chilliwack in the Fraser Valley of British Columbia, Canada, providing about 1,000 jobs in the construction phase and supporting another 100 employees  at the brewery at full production. To handle effluent from the new MolsonCoors $CAD200 million plant, which will produce beverages made with mountain-fed water at the foot of the North Cascade Mountains, the city of Chilliwack worked with Global Water Engineering (GWE) to build a high-strength wastewater pretreatment facility.

The anaerobic wastewater pretreatment installation was engineered to provide treatment performance of 85 to 90 percent biochemical oxygen demand (BOD) and chemical oxygen demand (COD) removal, which are measures of the amount of potentially polluting organic content in the wastewater. The technology is purpose-built to treat wastewater that is rich in organic content.

"The anaerobic wastewater pretreatment installation was engineered to provide treatment performance of 85 to 90 percent BOD and COD removal."

Wastewater from the MolsonCoors brewery will be pumped to the new Chilliwack anaerobic wastewater pretreatment facility, which is adjacent to the existing municipal treatment works. From there, it will pass to the Chilliwack wastewater treatment plant for final polishing and ultimate discharge. The anaerobic wastewater pretreatment facility, which generates operating income for the city while removing the need for the brewery to invest in its own operators, has a capacity of 1,500 m3 of wastewater a day, with COD removal of 7,500 kilograms.

This joint effort between the city of Chilliwack and MolsonCoors will provide a wastewater pretreatment process that safeguards the environment while facilitating jobs. The new plant is the third GWE facility installed to achieve high-quality treatment of MolsonCoors wastewater at other facilities.

In addition to producing high-quality effluent, the anaerobic design will require less energy than conventional aerobic treatment solutions, produce lower levels of waste sludge, and need less chemicals.

Biogas production from anaerobic digestion process

The anaerobic wastewater treatment facility can also produce biogas from the anaerobic digestion process. A portion will be used initially to heat the wastewater entering the anaerobic reactor, replacing the need to use fossil fuels to power the heating process involved. The excess biogas generated will ultimately be available for resale commercially, adding to the financial and environmental benefits of the pretreatment facility.

Based on past results for MolsonCoors and at GWE wastewater treatment and waste-to-energy plants, the facility could achieve an average daily biogas product of 910 kW a day, or 332 MW a year, if commercial customers are found. The high-quality produced wastewater and potential use of the resulting large quantities of biogas can further minimize the brewery’s environmental footprint.

Similar facilities in the U.S., Asia and Europe are generating millions of dollars of biogas — with high returns on investment, generated profits and lower demand for conventional energy sources such as oil and coal.

GWE has built and commissioned more than 200 biogas utilization plants over the past 15 years. Such plants produce green energy from pollutants present in wastewater using high-performance anaerobic bacteria to digest the dissolved and suspended organic matter, which is converted into biogas, a mixture of methane and carbon dioxide.

Anaerobic wastewater treatment for food and beverage processing plants

GWE’s system installed in the city of Chilliwack’s plant is designed based on an upflow anaerobic sludge blanket (UASB) type of anaerobic reactor, which accepts relatively high amounts of the biodegradable suspended solids in the influent. Its high BOD and COD removal efficiency allows users to install smaller aerobic polishing treatment subsequently, achieving low excess sludge production and power consumption in the aeration polishing stage.

Different configurations of technology have been deployed at food, beverage and agribusiness facilities worldwide, where they are used to transform wastewater treatment effluent from a disposal issue to a profitable source of green energy.

Food and beverage processing plants, including animal and crop processing plants, can install their own anaerobic wastewater pretreatment facilities — before discharging water into public systems — to protect their environments and meet statutory requirements using custom-designed municipal facilities such as the city of Chilliwack’s. 

Ian Page is vice president of GW&E, the North American division of GWE, a  global anaerobic treatment and organic waste-to-energy technology provider. He holds a bachelor’s and master’s degree in civil/environmental engineering and has more than 24 years of experience in wastewater treatment, recycling and reuse. Page has designed, constructed, started and operated  anaerobic and aerobic systems worldwide for a variety of industries, utilizing a range of technologies. He is a registered professional engineer in Texas and has authored or co-authored more than 35 technical papers and articles on industrial wastewater treatment.

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