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Green Beer, part 4
Water and Wastewater
December 2, 2004
Written by jercraigs
There are many compelling reasons to avoid overusing an important resource by conserving water at home. At a brewery the costs of water and wastewater treatment are also important considerations. Beyond the water itself, there is also a direct relationship between high water usage and energy consumption. This is especially important considering that the ratio of water used to beer produced can be as high as 20:1 in inefficient operations, or as low as 4.5:1 in breweries that have implemented water conservation measures. What are breweries doing to make the difference?
Turn Off The Taps
Literally - Turn off the taps. Common sense and good housekeeping practices can result in huge savings through small efforts such as replacing leaky faucets, ensuring that piping is in good condition, and shutting off water hoses. A large brewery that replaced its drinking fountains with water coolers yielded almost $45,000 a year in water savings. Small measures such as these may seem simplistic but consider this - a leak dripping just one drop of water a second can waste almost 1600L of water over the course of a year.
Some of the biggest water uses in a brewery include bottle and keg washing, cooling, pasteurization, cleaning-in-place (CIP) equipment, line and filler flushing water. The Anheuser-Busch Fort Collins Brewery in Colorado recorded the best water use efficiency of all domestic A-B breweries at the end of 2003, reducing water use per barrel by almost 12 percent from the previous year. To achieve this reduction brewery employees first performed a water audit to quantify flows throughout the facility and identify opportunities for improvements. Some key conservation measures implemented include eliminating steam, condensate and water leaks, optimizing water use during cleaning processes and equipment startup without affecting product quality, and installing a water recirculation system.
Moosehead Brewing improved their water efficiency through annual steam trap surveys, and increasing the distribution of monitoring data to their employees in control of energy expenditures. At many SAB breweries, the installation of water cooling towers allows for the recycling of clean cooling water while state of the art water meters allow them to monitor water usage elsewhere. The cost of implementing water conservation measures for smaller brewers can range from a couple of dollars at Home Depot for new hose nozzles to more expensive equipment replacement.
No matter how much effort a brewer puts into efficient water use, a brewery will still produce a lot of wastewater. For small breweries their water and sewage costs are typically minimal, and wastewater costs are not typically a major financial concern. It is interesting to note though, that some municipalities calculate sewage output costs based on the water input rather than actual sewage output. Wastewater reductions would therefore not yield similar savings in sewage charges. This also means that some brewers are paying sewage fees on water that goes out the door as beer rather than down the drain.
Obviously, wastewater costs are a bigger concern for large breweries if only for reasons of scale. Breweries can exert a large demand on municipal wastewater treatment systems because of the high levels of organic materials in the wastewater, and may therefore be charged substantial fees by local utilities. Two common measures of wastewater pollution levels are BOD5 levels, and the amount of suspended solids in the water.
BOD5 is the biochemical oxygen demand of wastewater during decomposition occurring over a 5-day period, this is used as a measure of the organic content of wastewater. BOD5 levels are also a concern in pulp and paper industry. A German study found that untreated brewery effluent typically contains suspended solids in the range 10-60 milligrams per liter (mg/L), BOD5 in the range 1,000-1,500 mg/L range, and nitrogen in the range 30-100 mg/L. Canadian results were comparable, with some materials such as BOD5 having wider ranges.
Brewers can reduce treatment fees by operating their own wastewater treatment plants, altering wastewater ph chemically or with C02, but this requires large amounts of electricity and energy. Breweries using anaerobic digesters reduce the need for such treatment options and can recover some of the energy used through the generation of biogas.
The Anheuser-Busch website says they are the world’s largest operator of Bio-Energy Recovery Systems (BERS). BERS is a method of anaerobically pre-treating wastewater and capturing biogas (methane). The biogas recovered is then burned as fuel at the brewery providing more than ten percent of A-B’s on-site fuel needs.
Anheuser-Busch uses BERS to treat wastewater at eight of its twelve breweries in the United States and at two international breweries in the UK and China. BERS systems have important environmental benefits: Pre-treating wastewater reduces its organic load by up to ninety percent, reducing the demand on community treatment facilities and the use of biogas to supplement boiler fuel purchases reduces the use of fossil fuels. In the past five years A-B averaged more than 1500 billion btus of energy production from biogas, and credits BERS operations with eliminating an estimated 200,000 tons of carbon dioxide emissions annually.
At the A-B brewery in Baldwinsville, New York, wastewater is treated with the BERS system and then a final aerobic polishing treatment process. This secondary process allows recovered biosolids to be used in landscaping and agricultural applications instead of being disposed of in a landfill. In 2003, the facility composted 21.2 million pounds of biosolids in this way. Critics of composting and spreading of "biosolids", or "sludge" from water treatment plants point out that if the sludge contains heavy metals or other hazardous materials it can contaminate soil and groundwater. This seems to be a greater problem for municipal facilities than for breweries, but a rigorous testing program to ensure its safety is advisable in both cases.
Still to Come
The focus of the last two parts has been on packaging and the waste that leaves the brewery. The next installment will take a look at things inside the brewery itself, specifically heating and cooling, lighting, and electricity use.
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