By Katariina Majamaa, Global Strategic Marketing Manager and Jake Moen, Technical Service Specialist, Dow Water & Process Solutions
Water is critical to the food and beverage processing industries where water and wastewater are key components of multiple operations. Prior to the introduction of the Clean Water Act in 1972, food and beverage facilities did not have regulations governing the release of their wastewater into local bodies of water. Today, companies are held responsible and therefore must better understand and manage their wastewater. This has led to a growing need in the food and beverage industry to implement wastewater treatment solutions that are affordable, reliable and low-maintenance.
While all sectors of the food processing industry, ranging from fruit and vegetables to meat, poultry, seafood and dairy, generate a large amount of wastewater, one sector stands out for its high strength and oftentimes high volume of wastewater: the Beer Brewing industry. In fact, according to the Brewers Association, most breweries discharge effluent, wastewater generated that is discharged to the sewer system, equivalent to 70 percent of their incoming water.
This article discusses the financial and regulatory challenges of high BOD (Biochemical Oxygen Demand) wastewater in the brewing industry, as well as treatment options brewers should consider helping reduce fines and increase the sustainability of their operations.
Brewers Faced with Impacts of High BOD Wastewater
The presence of craft breweries continues to climb, and today the world beer market amounts to billions of gallons per year. However, success comes with challenges. Breweries must contend with high BOD wastewater – a measure of oxygen used by bacteria (bugs) in five days – generated by their operations. This high BOD wastewater is taxing wastewater treatment plants and costing business owners money in the form of regulatory fines and higher fees from the receiving plants.
High BOD waste streams reduce oxygen levels as they are broken down. When sent untreated, this can produce an excessive load to local wastewater plantsÔÇöand if discharged directly, the reduced oxygen level (resulting from high BOD) can disturb ecosystems and have negative environmental impact. But aside from the desire for eco-friendly and sustainable solutions, there are other drivers pushing craft brewers to develop a wastewater strategy.
Brewers must comply with a combination of federal, state and local limits that can impact their facility. Failing to meet these expectations can lead to severe penalties or even discharge cessation.
If unaware of effective treatment options, craft brewers can be stuck paying unnecessary fees for the content of their wastewater. Municipalities can charge the breweries for discharging wastewater that exceeds TSS, Temperature, pH, and/or BOD limits, with the biggest fees often coming from the excess BOD surcharges. Currently there is a wide range in fees but even areas with low fees can expect to see increases as regulations continue to grow.
In order to send less polluted water to the wastewater plant and save on surcharge fees, brewers should consider point source treatment, which means treating the wastewater at the brewery prior to sending it down the drain.
Developing a Viable Wastewater Treatment Strategy for High BOD
A wastewater treatment strategy can have a big impact by reducing costs and liability. In order to develop the best wastewater treatment strategy for their operation, brewers should understand the following:
- What regulations apply to them (local, state and federal)
- Volumes of wastewater generated
- Strength of wastewater generated
- Costs they are incurring or should be incurring for their wastewater disposal
- How to reduce the liability (financial and regulatory) and impact of their operations
An effective strategy begins with assessing wastewater streams by characterizing the various streams that require treatment. Unfortunately, wastewater composition can be hard to quantify. Breweries must identify all wastewater streams generated from both regular operations and routine maintenance tasks, such as flushing and cleaning. Ideally, in order to understand the variable flow rates and variable strength of streams (both BOD and Total Suspended Solids (TSS), the minimum and maximum values should be quantified for each stream.
In order to test for BOD and TSS, brewers can test with monitoring equipment or collect samples and submit them to a laboratory. The effects of these processes and procedures can be taxing, as batch operations can make accurate assessments challenging, and there are multiple variables to keep in mind, such as whether all drains are connected to the same outlet, or whether some wastewater streams are segregated and handled separately. A good resource for making an assessment is the “Water and Wastewater: Treatment/Volume Reduction Manual” by the Brewers Association.
Assessing and Treating High BOD and TSS
Once a brewer has good knowledge of the wastewater streams in their operation, there are multiple treatment options available. These include segregation and collection, pH adjustment, flow equalization, and BOD/TSS reduction.
There are two types of BOD that must be considered: insoluble and soluble. The insoluble type has Total suspended solids (TSS), while the soluble type is dissolved in wastewater (e.g., streams with sugars or alcohols).
For solids removal, there are physical, chemical and filtration treatment methods. One example of a solids removal option is settling, with or without chemical addition. However, while solids removal may achieve 30-50 percent of total BOD, this method does not remove soluble BOD. Dissolved BOD poses a big challenge, based on the traditional options currently on the market today. Filtration through reverse osmosis or ultrafiltration is effective, but can be costly. For classic activated sludge, there remains a large footprint on top of high capital and operating costs.
The Craft Brewing Process: A Typical Facility
There are multiple steps in the craft brewery process (see Figure 1).
Depending on the brewery, there is a wide range of water used to produce beer, from three to eight barrels of water per barrel of beer (see Figure 2). What this means is BOD values for typical brewery wastewater can range anywhere from 2,000 to 10,000 mg/l with large variations. The sources of wastewater at breweries range from activities such as washing spent grain wash, which results in very high suspended solids (approximately 30,000 ppm TSS) and rinsing yeast for fermenting, which results in suspended solids of approximately 6,000 ppm and BOD up to 100,000 ppm. Beer spillage alone during the packaging process can result in up to 11,000 ppm BOD.
Source: Brewers Association, Water & Wastewater Treatment / Volume Reduction Manual
In order to effectively identify and assess point sources, brewers must consider:
- Daily volumes and range of flow rates
- Measuring BOD, TSS, pH
- Discharge limits
- Treatment targets
- Alternatives for treatment
Successful implementation of a treatment system requires attention to a number of key attributes: consistent performance, robust operation over a range of varying conditions, ease of operation, low initial capital cost and minimum ongoing operating cost, as well as scalability to support future plant expansions.
Finding a Reliable Treatment Solution
A growing number of craft brewers have found that an above ground, non-submerged bioreactor can reliably and cost-effectively minimize total wastewater volume and reduce discharge loads by rapidly treating high BOD wastewater streams at the source.
The following craft breweries piloted Dow’s Bio-Tower BX Module, a small 4′ X 4′ bioreactor, for use in a wastewater treatment process that also included filters with advanced cross-flow filtration to treat TSS up to 10,000 mg/L.
The bioreactor has a ceramic-coated fabric, which provides structure with a large surface area for rapid biome development and sustained growth, providing water and oxygen for efficient BOD reduction.
The resulting process is low energy, low odor and low solids generation. Compared to traditional treatment methods, this option has no blower requirements, can lift and move with a pallet jack and is scalable, allowing for the addition of more units as flow or load increases.
The objectives of this field performance was to measure BOD reduction under single-stage and two-stage treatment, confirm rapid buildup of biofilm and response to load swings, and stress test the technology.
Saint Arnold Brewing Company – Houston Texas
A single-stage treatment trial was completed at Saint Arnold Brewing Company, where 265 gallons of wastewater were treated daily. The average BOD was 4,140 ppm and the average TOC was 1,300 ppm.
By utilizing the bioreactor at the brewery, the results showed an average TOC reduction of over 88% as well as an average BOD reduction of over 88%. A high BOD stress test was conducted using high strength brewery wastewater with a starting BOD of over 5,000 mg/l (Figure 3). The triangles represent BOD sampling during the one-day test, which concluded with less than 200 mg/l of BOD, greater than a 95% reduction in BOD. These findings showed the modular design to have simple operation with high soluble BOD reduction, addressing rapid buildup of biofilm and robust to load swings.
Revolver Brewery – Granbury, Texas
At Revolver Brewery, there was a two-stage treatment trial, with a goal of maximizing BOD reduction. 265 gallons of wastewater was treated daily, showing an average BOD of 8,300 ppm and an average TOC of 3,861 ppm.
After the first stage, the average TOC reduction experienced was 75% and the average BOD reduction was 78%. When operated as a two-stage system the resulting average TOC reduction was 98%, and the average BOD reduction was 99%. The graph in Figure 4 shows a one-day snapshot of treatment with a starting BOD of nearly 8,000mg/l and the treated effluent of <100 mg/l.
These findings showed rapid buildup of biofilm, robust to load swings, with an extremely high (>99%) reduction of soluble BOD. Also noteworthy is the dissolved oxygen (DO2) increased during the treatment process due to the BioTower’s water distribution and natural ventilation.
In conclusion, the use of the bioreactor in brewery pilot testing determined high BOD removal efficiency in both single- and dual-stage configurations.
What Next? – Assessing and Investigating
For both breweries and other companies in the food and beverage industry, the next step is assessing the wastewater conditions at the facilities they operate. To do so, brewers should obtain copies of the applicable regulations and determine the wastewater flow and flow patterns present at the facility. It is important for plants with little or no wastewater treatment strategies to understand the flow, load and regulatory limits, look for opportunities to minimize total wastewater volume, and investigate methods to reduce discharge loads.
Looking Forward: The Future of Wastewater Treatment for Food and Beverage
By utilizing a compact, low-attention bioreactor as part of a wastewater treatment strategy, companies in the food and beverage industry can improve the quality of their wastewater streams.
Conserving water and reducing the amount of BOD, TSS, and other materials in food and beverage industry wastewater can not only save money, but can also reduce the facility’s environmental impact. Brewers and facility managers alike are able to reduce the liability and impact of brewery operations, both financial and regulatory, and make their facilities better models of sustainability.
About the Authors
Katariina Majamaa is a global strategic marketing manager at Dow Water & Process Solutions (DW&PS). She is responsible for developing and implementing global strategies with the objective to grow value for end users and for heavy industry applications requiring ultrafiltration, reverse osmosis, nanofiltration, ion exchange and high solids filtration technologies. To contact her email: email@example.com.
Jake Moen is the North America Technical Service Specialist focusing on the Dow™ Ultrafiltration, Electrodeionization and Bioreactor products for Dow Water & Process Solution (DW&PS). In this role, he is responsible for technical assistance with project design, product development and field support for North America. To contact him email: firstname.lastname@example.org.
 From “Water and Wastewater: Treatment/Volume Reduction Manual” by Brewers Association, https://www.brewersassociation.org/attachments/0001/1517/Sustainability_-_Water_Wastewater.pdf