Liquid Gold: Save, Make Money from Wastewater Resource Recovery
There‚Äôs money to be saved ‚ÄĒ and made ‚ÄĒ in industrial wastewater. A growing number of organizations are recognizing this, and saving on water and energy bills by treating wastewater to produce freshwater and electricity.
Last week Kona Brewing Co. said its new high-efficiency brewery will include an on-site resource recovery center, built by PurposeEnergy, that will allow the brewery to recycle its wastewater and other brewing byproducts to produce electricity, heat and clean water for the brewery. Kona Brewing says the resource recovery center will help it reduce its water usage to less than half what typical craft breweries use.
‚ÄúWe were faced with a challenge to figure out how to build a brewery that would more than double our capacity with only half of the amount of water that is typically required to operate a craft brewery,‚ÄĚ says Sandi Shriver, head of brewery operations for Kona Brewing. ‚ÄúWe also learned that the scope of our operation would burden the existing infrastructure of the county wastewater facility.‚ÄĚ
Shriver says a typical craft brewery needs between six and eight volumes of water to produce one volume of beer. Most of this water is used to clean vessels, the brewery, and utility operations. Recycling this water used for cleaning and other brewery operations would save incoming freshwater for making beer.
‚ÄúWe partnered with PurposeEnergy which had a solution to not only reduce the amount and strength of our wastewater to the county to well below what they could handle, but also return clean recycled water to the brewery,‚ÄĚ Shriver says. ‚ÄúIt was just enough to get us to where we needed to be from a capacity standpoint. As a bonus, we could generate 30 percent of the energy needs from burning the biogas byproduct.‚ÄĚ
Turning Wastewater into Biogas
Lux Research‚Äôs Abhirabh Basu, a research associate on the firm‚Äôs water team, says industrial markets and municipalities can recover resources from wastewater, or sludge, two ways: installing anaerobic digesters or adding chemicals like magnesium chloride into wastewater to remove and upcycle nutrients.
Installing anerobic digestion systems, upstream of wastewater treatment, reduces high levels of chemical oxygen demand (COD) for the downstream biochemical oxygen removal (BOD). The process produces a valuable byproduct, biogas (methane), which can be used to power wastewater treatment.
Basu says while aerobic digesters are usually installed at large treatment plants ‚ÄĒ these are more likely to offset the high capital investment from onsite energy production ‚ÄĒ technological improvements are making wastewater resource recovery more accessible.
‚ÄúWe are also seeing technology improvement for processes like thermal hydrolysis, offered by companies like CAMBI As and Veolia, that pretreat sludge at high temperature and pressure to recover as high as 50 percent more biogas during the digestion step and reduce overall sludge volumes,‚ÄĚ Basu explains. ‚ÄúWe think such techniques are gradually going to penetrate deeper into both developed and developing markets where energy cost are high and sludge disposal is a logistical problem.‚ÄĚ
Industrial markets, like food and beverage, that produce wastewater with high concentration of fats, protein and hydrocarbons make a good source for biogas. Kona Brewing is a good example of this, as is a recent onsite wastewater treatment that Veolia designed and built for multinational food manufacturer Associated British Foods (Thailand). Veolia says the end-to-end wastewater package will allow ABF to handle its wastewater treatment needs on premise while also generating biogas.
Faced with the challenge of designing a wastewater treatment plant located within the client‚Äôs space constrained manufacturing grounds, Veolia recommended technologies that could effectively treat ABF‚Äôs wastewater volumes and COD loads. Veolia‚Äôs Michael Poonpipat says the company‚Äôs water and wastewater systems‚Äô compact designs take into account ‚Äúspace constraints that clients face without compromising on performance.‚ÄĚ
New Revenue Streams for Wastewater
The second resource recovery method ‚ÄĒ adding chemicals to wastewater ‚ÄĒ creates new revenue streams for wastewater by allowing nutrients such as phosphorous and nitrates to be extracted from wastewater and then sold for agricultural applications. For example, Ostara‚Äôs technology recovers 85 percent of the phosphorus and nitrogen from wastewater streams at municipal and industrial wastewater treatment plants and transforms them into fertilizer, marketed as Crystal Green.
‚ÄúWe see some interest in the market for recovering organic and inorganic material from wastewater, but this is largely driven by regulatory enforcement rather than speculations of ‚Äėpeak phosphate,‚Äô‚ÄĚ Basu says. ‚ÄúWhat is more valuable is recovering precious metals, like gold and copper, from industrial waste streams or run-off such as mining, semiconductor processing, and surface treatment of metals. Companies that do this include AMS Technologies and NanoStruck Technologies.‚ÄĚ
As water and energy prices increase, expect more companies to turn to sludge as a way to save on utility bills and conserve resources.
‚ÄúWe have the technology today to really take water conservation to the next level,‚ÄĚ Kona Brewing‚Äôs Shriver says. ‚ÄúThese technologies are definitely not inexpensive, but if companies are able to focus on being as sustainable as possible and willing to make the investments, the technologies will continue to improve and lower the cost for everyone.‚ÄĚ
Photo Credit: wastewater treatment via Shutterstock
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