Close to five thousand licensed craft brewers are operating in small towns across Canada and the United States, with revenues exceeding $30 billion (Canadian) per year. Small breweries support local economies, contribute to tourism, and create jobs, but also can pose a problem for aging wastewater treatment infrastructure. It’s no longer an age where factories, breweries included, can just dump their wastewater into a local river (thank goodness). Laws and regulations that dictate how water must be kept clean prevents that from happening.
With breweries, untreated wastewater in rivers can cause nutrient pollution. Further, it is high temperature, high in sugar, low pH, has the potential to be high in solids, and is high in alcohol compared to regular domestic wastewater, putting a strain on wastewater treatment facilities. Read on to learn more about these issues and how wastewater treatment systems can be the solution.
1. Nutrient Pollution
Untreated wastewater from breweries causes nutrient pollution, which leads to large algae blooms. Algae blooms have severe impact on aquatic ecosystems, the economy, and human health. They can be toxic! Furthermore, nutrient pollution makes it more difficult for fish to gain the proper amounts of oxygen from the water, which leads to fish die-off.
2. High Temperature
The best temps for wastewater treatment range between 77 and 95 degrees Fahrenheit, or 25 to 35 degrees Celsius. Biological treatment will accelerate in warm temperatures and slow in cool temperatures; however, extreme heat in wastewater can stop treatment processes altogether. When dumped into receiving streams in large quantities, hot water alone can raise the temperature of receiving streams and disrupt the aquatic life.
3. High Sugar and Alcohol
The sugar and alcohol together create high biochemical oxygen demand, also called BOD. These nutrients have to be consumed by bacteria in a wastewater treatment plant before being discharged to the local body of water. High BOD wastewater put out by breweries puts a strain on the wastewater treatment plant, primarily in the electricity needed to treat it.
Large blowers are used to aerate the water, which gives bacteria the oxygen needed to consume all the nutrients. The more nutrients in the water, the more aeration is needed, which translates into more money being spent to clean the water.
Brewery wastewater can be highly corrosive both to brewery equipment and to municipal-omened pumps and pipes. Low or high pH wastewater, in addition to hydrogen sulphide gas, are the main culprits of corrosive wastewater. The wastewater from breweries is naturally acidic, typically around 4.5 pH.
There are times, however, when the wastewater can also be high pH depending on the CIP cycle. As the water sits, the pH will lower. Different municipalities have different discharge limits so it all depends on local laws regarding at what pH your wastewater may to be discharged.
Hydrogen sulphide gas is another corrosive issue. In the presence of water vapour, H2S creates sulphuric acid. This will eat away at concrete over time, as well as any steel it comes in contact with during its travels.
5. High in Solids
Solids in brewery wastewater tend to be small grain particles and yeast, but larger solids can also make their way down the drain like shrink wrap, wrenches, TC fittings, and more. Solids are likely the easiest to address in brewery wastewater because they can be removed mechanically. Screens in the floor drains to catch the larger particles are a great option; however, the best option is to not put solids in the drain in the first place.
Another problem of brewery wastewater is that solids can grow in your warm, sugary wastewater tank, creating a thick sludge at the bottom of the tank. This will also need to be addressed before it causes a backup in your tank.