Onsite Water Reuse: Addressing Fermentation’s Water Footprint

Fermentation is used in a wide range of industries, including biofuels, pharmaceuticals, and food and beverage production. In recent years, the use of fermentation in sustainable initiatives, such as alternative protein production or the replacement of materials traditionally derived from petrochemicals, has been rapidly increasing. Fermentation processes use a significant amount of water with typical uses including growth media makeup, downstream processing, clean in place (CIP), sanitization, cooling and steam generation, and area washdown.  As an example, breweries can use 6 to 10 gallons of water to produce 1 gallon of beer if they do not implement water conservation and reuse measures. 

Photo credit to GPC Bio.

Water usage is typically a major consideration for fermentation scaleup and can be a limiting factor to site selection or expansion due to permitting regulations on water consumption and wastewater disposal. Water use reduction and reuse offers solutions to this scaleup challenge.

Rather than disposing of this process water after it is used in the fermentation process or downstream processing in a once through manner, it can be treated to remove impurities and contaminants, making it suitable for reuse in media makeup in subsequent fermentation batches or for applications such as equipment clean in place or utility make-up water.  The water quality and treatment requirements will depend on whether the process requires potable water as a starting ingredient and the local regulatory environment.  Advanced wastewater treatment can generate water cleaner than EPA drinking water standards on site.

Water reuse presents both economic and sustainability benefits: reducing freshwater usage requirements results in lowered utility costs and can help reduce the overall water footprint in a Life Cycle Analysis (LCA).

There are several factors to keep in mind when implementing water reuse in a fermentation process. First is the quality of recovered water, which is crucial for the success of the fermentation process. Secondly, the economic feasibility of treatment must be taken into account. And lastly, the regulatory/permitting environment is crucial well. The main challenges to consider in designing a reuse system include the potential for accumulation of fermentation inhibitors, risks to system microbial controls, and degree of pretreatment required for successful reuse system operation without introducing significant operational or cleaning (with additional water usage) requirements. 

So where to start when developing and implementing a water reuse strategy?

At Next Rung Technology, we have found that a good first step in developing a water reuse strategy is to perform a water audit. A comprehensive assessment of each water user and each wastewater generator in the facility or process, involving water data collection if feasible, development of a water balance, and definition of quality requirements. Such an assessment can be used to define the water efficiency of the facility and identify localized or overall opportunities for water reuse.  An audit can help identify opportunities for segregating less contaminated waste streams for reuse prior to combination with other streams.

The next step is typically a technology option evaluation identifying the most appropriate treatment technologies for the specific water reuse application. Treatment goals should first be determined, including parameters such as turbidity, total dissolved solids (TDS), hardness, pathogens, and organic and inorganic contaminants. Typical technologies in play can include biological treatment, ultrafiltration, reverse osmosis, granular activated carbon, and ozone or UV disinfection. Criteria such as capital and operational costs, energy requirements, reliability and maintenance requirements, compatibility with the intended use, and regulatory compliance should be considered in developing the final plan.

New sustainable technologies such as fouling resistant membrane systems and electrochemical wastewater treatment are continuing to raise the bar and expand the toolbox of options for industrial water reuse. At Next Rung Technology, we routinely work with these types of emerging sustainable technology companies.

Let’s be honest, the challenge of water scarcity is not going anywhere. We predict industrial onsite water reuse will need to become a standard part of the design for fermentation processes and facilities as a result. Thus, we encourage you to get a jump on the competition and start your own water audit today.

If you need some extra capacity for this effort, don’t hesitate to reach out we would love to hear about your project!

Photo: RO Membrane Skid