Wastewater produced by breweries is rather unique. The brewing process creates alcohol, sugars, and proteins that all end up in its wastewater. If brewery wastewater rich in nutrients is discharged without the correct treatment it can seriously interfere with natural ecosystems.
Brewery wastewater has a high BOD, “biochemical oxygen demand”. In other words, it needs a lot of oxygen for decomposition. In rivers, large algae blooms form in nutrient-rich wastewater. As they feed off the nutrients, they leave little oxygen for the fish. And that’s just one example of how untreated brewery wastewater can harm the environment.
Can you imagine that it used to be acceptable for breweries and other industries to pump their wastewater to the nearest river? Not anymore thankfully! Here’s a very basic breakdown of some modern techniques that make brewery wastewater safe for discharge to the environment. The same often applies to industries that produce nutrient-rich wastewater. For example, the restaurant wastewater treatment process or food and drink wastewater treatment processes.
Brewery Wastewater Treatment Processes
Removal of Heavy Solids
Brewery wastewater is usually treated in stages by passing through a series of tanks. The first step is the removal of the solids in the brewery wastewater. Brewery wastewater is solid heavy due to the all the grain from the brewing process like barley and hops for example. Coarse and fine mechanical screens filter out the solids in the first step of the treatment process.
Removal of Lighter Solids and Biochemical Treatment
Aeration inside Buffer Tanks
Once the heavy solids are gone, the remaining wastewater needs biochemical treatment. Buffer tanks allow the brewery wastewater to pass through the system in set quantities, rather than a constant flow. The buffer tank fills to a certain extent before it periodically empties wastewater into the next tank in line. This allows really thorough treatment of the wastewater. It also helps the system to cope with shock loads. The buffer tank may even carry out part of the treatment process itself. For example, aerated buffer tanks, as the name suggests, add oxygen to the wastewater to help the bacteria break down the nutrients faster.
Suspended matter in the wastewater, like oil for example, is then removed by a process known as DAF “dissolved air floatation”. Air is dissolved under pressure in the wastewater, then released again at atmospheric pressure. This causes tiny air bubbles to stick to the suspended matter and form a foam which floats to the surface and can then be skimmed off.
A lamella clarifier removes small particles from liquids in a settling process using a series of inclined plates. Solid particles begin to settle on the plates and accumulate at the bottom of the clarifier unit. The sludge is drawn off the bottom and the clarified liquid exits the unit over a weir at the top.
Fixed Bed Reactor
The fixed-bed reactor is a submerged structure with a large surface area that microorganisms can grow on. This creates a biofilm for the wastewater to pass through, filtering out biochemicals to feed the microorganisms. Aerators provide the oxygen for the chemical breakdown process.
Brewing up a storm
To conclude, thanks to technology in wastewater treatment we can keep our environment safe from the harmful byproducts of the brewing process. In order to continue enjoying the good stuff breweries come out with we need to keep improving the ways, we deal with the not so good stuff! Leading wastewater engineering companies have developed many economical and eco-friendly sewage treatment solutions for breweries. Click here to see some examples.
By law, all new and existing breweries need to ensure that their wastewater is safe and clean. Otherwise, they could face closure, or hefty fines and penalties. Environmental authorities are responsible for keeping a check on it. We’ve definitely improved our standards since the heydays of dumping rich raw waster into rivers and lakes!