Portfolio

Master of Science

Environmental Policy & Management

Abstract

The brewing industry is one of the largest industrial users of water (Olajire 2012). Much larger quantities of water are required for other industries, agriculture and industrial uses for example (Schewe et al. 2014). With the popularity of beer displaying an increasing trend, this leads to potential problems with climate change and global water shortages. Breweries need to make changes to their production methods to cut back on costs and be more environmentally sustainable. This paper discusses the methods and technologies available for breweries to implement in their processes and also what methods breweries are currently using to decrease their water usage. Alternative methods will be suggested along with an in depth comparison between two of the novel technologies and their effect on chemical oxygen demand (COD) reduction. There are multiple avenues for reusing brewery wastewater ranging from selling spent grains as cattle feed to reusing spent yeast as a fertilizer, however new methods in filtration and microbial fuel cell technology (MFC) have a lot of potential. Both nanofiltration and MFCs will be covered in this paper. The expectation is to see a high percentage of COD removal in both nanofiltration and MFCs after conducting an experiment for each. In a comparison to each other, MFCs should be the more effective method since it removes COD allowing for reuse of the wastewater, but it also produces useable electrical energy as a byproduct. 

Introduction

Water is the most important natural resource on the planet. It is used for drinking and sanitation, but also has a multitude of agricultural and industrial uses. Many populations face water shortages mainly from lack of access and the water being low quality or unsafe to drink. Expected future population changes will occur in many countries as well as globally, this will increase the pressure on available water resources. (Schewe et al. 2014) To add to these problems, climate change is already altering precipitation in many areas, thus leading to uncertainty for the future of precipitation rates and access to fresh water (Schewe et al. 2014).

Beer is a very popular beverage, and is the fifth most consumed beverage globally. It is estimated on average 23 litres/person annually is consumed (Fillaudeau, Blanpain-Avet, and Daufin 2005, 463). Water is the main ingredient in beer, and many breweries select the location of their production buildings in areas with high quality city water. Basically stating large volumes of water are used during the beer brewing process (Simate et al. 2011, 236). 

To better understand the scope of the brewing process, it begins with malting barley. Barley is steeped in water to foster germination. The germination process builds up necessary amino acids and enzymes needed later in the brewing process. The germinated barley is then kilned and roasted to various degrees depending on what flavor profile is requested by the brewer. The dried barley is then crushed in a mill and then slowly added to hot water in large mash tun, where amylases from the grain are simplified to sugar (Gillespie and Deutschman 2010, 1244). The sugar rich water (wort) is then lautered/filtered over to the boil kettle, where it is boiled to sterilize it (Olajire 2012, 3). The wort is then centrifuged to separate out the last remaining solids and coagulated proteins (Gillespie and Deutschman 2010, 1244). The wort is then mixed with yeast to start fermentation. This brief summary of the brewing process details the steps each brewery uses. Each of these processes requires copious amounts of water and energy and also produces wastewater. 

Breweries have begun laying the groundwork to implement new wastewater recycling technologies into their own operations. This paper investigates how fresh water conservation and environmental sustainability can be improved through advancements in biological treatments, nanofiltration, and microbial fuel cell technology.

Literature Review

There have been significant improvements in wastewater treatment and recycling, however water consumption and disposal are critical factors when considering environmental and economic issues. (Filladeau et al. 2006; Olajire 2012). This problem combined with the scarcity of freshwater, which already constrains development and well-being in many countries; with population growth and increase in economic prosperity, water demand will increase which will aggravate water shortages (Schewe et al. 2014, 3245). Breweries produce copious amounts of wastewater, and these large volumes must be disposed of and treated with cost, health, and the environment under intense consideration (Simate et al. 2011; Olajire 2012). It is estimated that for the production of 1 L of beer, 3-10 L of waste effluent is generated depending on the production of specific water usage (Simate et al. 2011; Braeken et al. 2004; Fillaudeau et al. 2007). There are methods and technologies available to treat and recycle brewery wastewater. The most relevant and promising being nanofiltration, anaerobic/aerobic respiration, microbial fuel cell technology, and alternative methods of waste disposal.

Nanofiltration

Nanofiltration removes small organic compounds and ions and in a wide range of applications it has already shown successful results for the removal of organic compounds in water and waste waters (Braeken et al. 2004). Braeken et al. (2014) also analyzed waste water from a Flemish specialty brewery, where they collected waste water from different stages of the brewing process. In comparison, Gotz et al. (2014) analyzed brewery wastewater slightly different; they sampled seven different breweries with similar product lines and wastewater streams. Nanofiltration and other membrane technologies were explored in the literature analyzed for this topic. Nanofiltration was analyzed the most due to its success rate, compared to ultrafiltration with lower success rates.  The main factor when considering the success of filtration is the COD levels after the filtration is completed. The concentration of organic material is usually measured as chemical oxygen demand (COD). Brewery wastewater typically has a high COD from all the organic components (sugars, soluble starch, ethanol, volatile fatty acids, etc) (Olajire 2012; Simate et al. 2011; Filladeau et al. 2006). The final argument for nanofiltration comes from (Simate et al. 2011) where they compared nanofiltration to aerobic/anaerobic treatment and microbial fuel cells which are also covered extensively in this paper.

Aerobic/Anaerobic Treatment

Aerobic biological treatment is performed in the presence of oxygen by aerobic microorganisms (Simate et al. 2011; Olajire 2012).  Who also further analyzed more specific methods of aerobic treatment of brewery wastewater.  Simate et al. (2011) also analyzed anaerobic treatment, which is the biological treatment of wastewater without the use of air or elemental oxygen. They also further analyzed more specific methods of anaerobic treatment, and the combination of both aerobic and anaerobic methods together to find the most effective treatment of brewery wastewater.  Another approach applied by Olajire (2012) 

consisted of an overview of the brewing process and analyzing the many benefits of aerobic and anaerobic treatments of brewery wastewater. Olajire (2012) analyzed other alternative methods of wastewater and effluent recycling, weighing the advantages and disadvantages of each method, while incorporating feasibility of implementation. Aerobic granular sludge reactors were analyzed by (Corsino et al. 2017) who also established an effective procedure then proceeded to run through trials to find a successful balance of bacterial metabolic rates with treating brewery wastewater. 

Microbial Fuel Cell Technology

Microbial fuel cells (MFCs) represent a new method for treating wastewater and simultaneously producing electricity (Mathuriya and Sharma 2010). They conducted experiments with this new technology, sampling the Central Distilleries and Breweries Ltd. Meerut, India. They also gathered samples from different stages of the brewing process, and ran them through the microbial fuel cells. Both (Mathuriya and Sharma 2010; Olajire 2012) found this relatively new technology to be successful. MFCs can also be combined with anaerobic and aerobic processes to improve efficiency (Olajire 2012). Simate et al. (2011) also found similar results when exploring MFCs, particularly, sequential anode– cathode type, which can provide a new approach for brewery wastewater treatment while offering a valuable alternative to energy generation. This novel new approach to treating reclaimed brewery process water is both promising and thoroughly researched.

Alternative Methods

There are different drivers of water usage in a brewery, from hygiene to brewery size. Kirstein and Brent (2017) gathered data from 64 SABMiller sites and conducted surveys from experts in the industry to have them rank the main drivers of water usage in breweries. They found improvements in management and operating practices to be where water usage could be decreased. Similarly, (Fillaudeau et al. 2006) identified the main areas in a brewery where water usage is highest and also highlights areas where breweries can conserve water while providing many alternatives; ranging from disposing of surplus yeast to spent grains. The environmental impacts of brewery wastewater and water conservation are explored extensively by (Olajire 2012, 1), and many different suggestions to dispose and reuse wastewater are reviewed. Olajire (2012, 3) also reviews how spent grains and yeast surplus can be reused or sold by breweries for profit. Another approach to review water conservation in breweries is similar to both of the previous articles, Simate et al.( 2011) does investigate the cause and effect relationship between legislative and environmental management systems and brewery waste water treatment methods. Their review of previous research and literature allows them find plenty of advantages and disadvantages of these methods and also provide many new alternatives; from lagoons to vertical biological reactors for example. 

This purpose of this paper is to synthesize existing literature and compare nanofiltation and MFC experiments to address current methods of water conservation in breweries; while also looking ahead to what breweries can start implementing in their processes to run more efficiently with environmental sustainability and combatting climate change being the goal. 

Methods

The main focus of this experiment is the comparison of microbial fuel cell technology to nanofiltration. Both methods have been successful in treating human wastewater, and there are many parallels in treating brewery wastewater. The main goal is to analyze the data collected from each experiment and determine which of these methods is most effective in removing COD from brewery wastewater streams. 

Sample Collection

The brewery wastewater was collected from Denver Beer Company, a local craft brewery in Denver, Colorado. We contacted the general manager at the brewery and asked if he would be interested and willing to let us gather samples from the brewery’s wastewater sources. We then provided him with an informed consent form, which carefully outlined the methods we were going to use and the potential risks. We also assured him no trade secrets or employee personal information was to be collected. Careful coordination with the brewery staff was required to ensure we collected the appropriate wastewater samples. The wastewater was collected in three different areas of the brewing process, brewing/mashing, cellar/fermentation, and bottle rinsing.

Nanofiltration Experiments

The filtrations system used was the ROMEMBRA Toray RO Membrane, manufactured by Toray Ind. Inc. (ROMEMBRA RO Toray 2018). It features multiple membranes per system with activated carbon. The filtration experiments were conducted in a laboratory scale. First the membranes were flushed with pure water to establish flux rate, and then followed by the wastewater for three hours. The filtration systems were rinsed and cleaned between each cycle with distilled water, and new filters were set up between each pass (Braeken et al. 2004, 3076). 

Microbial Fuel Cell (MFC) Sample Collection

For the microbial fuel cell experiments, brewery wastewater samples were collected from the same craft brewery, Denver Beer Co. in Denver, CO. The wastewater samples were split into nine 1 liter bottles. Each sample was left to settle any particulates for 24 hours under anaerobic conditions (Mathuriya and Sharma 2010, 71). Just as before, we contacted the brewery prior to sample collection to request permission and put them through the same informed consent process, so we could use their wastewater for the experiments. The wastewater was also analyzed for COD content before and after the experiments, and all COD measurements were collected using standard methods (American Public Health Association and American Water Works Association 1998).

Microbial Fuel Cell (MFC) Experiments

MFC devices use bacteria to convert chemical energy from the wastewater to electrical energy, which are designed for anaerobic treatment. Eight reactors were used and filled with fully concentrated wastewater and operated at 30°C. Each run took four days to complete (Feng et al. 2008, 873).  Electricity production was measured by a Digital Multimeter every 24 hours. Each run was operated at 35⁰C (Mathuriya and Sharma 2010, 73). 

Analytical Measurements

Chemical oxygen demand (COD) is the variable we are targeting through treatment. COD measurement is considered sufficient in showing the amount of organic material in water (Simate et al. 2011). COD measurements were taken before and after each pass through the nanofiltration system, through standard methods (American Public Health Association and American Water Works Association 1998). Overall, after both experiments have been conducted, the data will be analyzed to determine which method was more effective in eliminating COD from the wastewater streams. Since we collected wastewater from three different streams, it was also necessary to compare the COD removal from each type, brewing/mashing, cellar/fermentation, and bottle rinsing.  In regards to MFCs, we will be looking at the cost/benefits of COD removal and electricity production.

Results

COD is the most important factor when considering recycling brewery wastewater (Braeken et al 2004, 3078). When comparing COD removal between MFC technology and nanofiltration, both should yield a high percentage of COD removal if not complete removal. The next variable investigated would be efficiency, mainly how long it will take to reach high percentages of COD removal when using both methods.  It is predicted that nanofiltration will require significantly less time to clean up the wastewater compared to MFC’s. It is known that Industrial uses of nanofiltration for human drinking water have proven to be successful. There is even success removing cleaning additives in bottle rinsing water (Braeken et al. 2014, 3076). It is hypothesized that nanofiltration and MFC’s will both completely remove COD in the brewery/mashing and cellar/fermentation wastewater streams, however they both will be unsuccessful in removing COD from the bottle rinsing stream. Therefore, bottle rinsing water will not be a candidate for brewery wastewater recycling.  The high COD levels in the bottle rinsing streams derive from the high concentrations of ethanol in the stream (Braeken et al. 2014, 3078).  

Despite both methods being effective in COD removal, MFC’s will also produce electricity while treating the brewery wastewater. Voltage will be produced easily and rapidly through operating the MFCs (Feng et al. 2008, 875). MFCs will sufficiently treat brewery wastewater, while also providing an alternative energy source (Simate et al. 2011, 244).

The remainder of this experiment would be to compare the findings with the nanofiltration and MFC experiments to the alternative methods and biological methods mentioned in the literature review. Breweries have already implemented many methods in disposing of wastewater and reusing it. Spent grains can be sold as livestock feed and fish feed, and using these biological wastes with agricultural purposes (Fillaudeau et al.  2006, 466).  These alternatives help with disposal of brewery wastewater but lack the recycling aspect much needed for water conservation, and not all breweries are capable of these methods.

I will only be able to analyze nanofiltration and MFCs with the limited amount of samples we gathered. There are many different types of breweries, and each brewery produces a wide array of beers. Each of these beers will have a slightly different chemical composition in the wastewater; and with unlimited funding and resources each of these wastewater streams could be treated and analyzed to determine compatibility.  This is one limitation with this current experiment and other similar experiments.

To maintain validity with this experiment, the construct method would have to be implemented. The underlying theory behind this experiment is COD removal from brewery wastewater. Each of the experiments conducted and methods discussed revolve around this central theme. This allows for extensive and thorough analysis of the experiments conducted from other industry experts. 

To establish reliability, the inter-rater method is the best choice. The main focus of this method is data collecting and observations, and using them to establish themes within the experiment. The inter-rater method is the backbone of this experiment, and the key driver behind finding out how effective nanofiltration and MFCs are with COD removal.

Conclusion

Overall, the use of biological alternatives is still prevalent and severely limited because many breweries do not have the capabilities to sell or give away their waste to potential buyers nor can they combine aerobic/anaerobic processes in treating their wastewater. The technological alternatives discussed in this paper fulfill the demand for treating and recycling brewery wastewater. Nanofiltration and MFCs aid in conserving fresh water for reuse, while also reducing the amount of waste produced. Both are extremely effective, but MFCs offer the opportunity to treat and reuse wastewater while producing electricity. The limitations on this study derive from an efficiency standpoint, MFCs will take this experiment approximately four days to complete, based off of other similar experiments. Since breweries are producing large quantities of wastewater to meet the high demand for their products, this technology will need to be optimized to run faster to cope with large volumes of wastewater. Nanofiltration does take less time, but breweries lose out on generating electrical energy. Feasibility becomes an issue as well; many of the articles and experiments I analyzed did not discuss real world applications of these technologies in actual breweries. Finding ways to implement MFCs and nanofiltration in breweries would be the new frontier in this topic. Overall, microbial fuel cell technology is the future; and eventually this technology will help breweries promote environmental sustainability and water conservation. 

References

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