Addressing Wastewater Head On

Actions are aligning around dairy’s least sexy issue – the wastewater streams generated by dairy processing – and this alignment of negotiated regulation, improved engineering and a new emphasis on research can yield the equation, dairy growth = a cleaner environment.

DNR N Permits
For two years, the Wisconsin cheese industry and state’s Department of Natural Resources have been working through a new approach to address nitrogen in dairy plant waste streams.

This ubiquitous element found in cow’s milk becomes a part of the clean-up water at dairy plants, and cheese makers and DNR have discussed how soil treatment systems such as spray irrigation fields and ridge and furrow systems treat nitrogen.

This fall, the department adopted new language for state wastewater permits recognizing that these soil and cover crop systems are now engineered and operated to remove more nitrogen than previous limits allowed, and industry has agreed that new, higher limits for nitrogen will be monitored by adding groundwater monitoring wells at treatment sites. It’s an agreement that will allow these tried and true treatment systems to continue operation into the future, and allow dairy manufacturers to grow their businesses.

Nitrogen Research
A key component to this nitrogen negotiation was each party agreeing that sound science, not speculation, should guide an understanding of these wastewater treatment systems. Wisconsin Cheese Makers Association has joined with Wisconsin’s Department of Natural Resources and Midwest Food Processors Association to develop new research into the efficacy of soil treatment systems.

The University of Wisconsin soil science department will structure a two-phase research project, beginning with a review of existing research and following up with field testing of, for example, nitrogen uptake and de-nitrification at existing spray fields and soil systems. Each party has agreed to fund this third-party research and in October, the WCMA board of directors pledged $50,000 to move this research forward.

Challenging Phosphorus Regulations
Another nutritional element found in cow’s milk, phosphorus, has played a central role in wastewater treatment discussions following Wisconsin’s 2011 adoption of new, stringent water quality standards for phosphorus entering Wisconsin’s rivers, streams and lakes. Wisconsin leaped ahead of other states with new phosphorus limits 10x lower than previous limits in wastewater permits.

Wisconsin’s municipalities and villages, cheese makers, food processors and paper mills are struggling to find technologies to meet standards as low as 0.075 mg/l phosphorus in their wastewater streams. For most, new limits will require the addition of multi-million-dollar filtration systems to make already-cleaned water slightly cleaner.

Today, public utilities and private companies are discussing with regulators common-sense alternatives, such as a longer time frame to develop new technologies or simpler ways to support off-sets from agricultural use of phosphorus, to meet the new water quality limits.

Water Quality at a Cost
To find a bright side to the challenging issue of stringent phosphorus regulations, one industry engineering firm, Probst Group, reports that new high-tech, high-cost systems are, at least, proving successful.

One large scale operation in Wisconsin, treating combined whey and high strength wastewater with a simplified anaerobic pretreatment process, is finding COD (chemical oxygen demand) reduced by 99 percent and phosphorus reduced by 75 percent – simplifying further steps needed to remove more phosphorus.
WEP in Milwaukee

Milwaukee is host to the Water Equipment & Policy Center, an industry and university center created by the National Science Foundation. The WEP focuses exclusively on water quality issues, with an emphasis on applied research and product development.

Administrative money for the Center, which includes labs and professors at University of Wisconsin–Milwaukee and Marquette University, comes from NSF. Research dollars come from private industry partners.
Energy production from wastewater streams is a major focus at the Center, with Milwaukee Metropolitan Sewer District at the table as one of WEP’s industry partners. A recent Marquette study performed for WEP by Dr. Daniel Zitomer’s team at Marquette found that addition of acid whey to anaerobic digesters at a municipal treatment site raised methane levels dramatically, and above theoretical levels.

The conversion of wastewater from a headache into an energy resource is another example of how proactive research and open communication between industry, academia and regulators can yield the equation, dairy growth = a cleaner environment. JU

John Umhoefer has served as executive director of the Wisconsin Cheese Makers Association since 1992. You can phone John at (608) 828-4550; Fax him at (608) 828-4551; or e-mail John Umhoefer at jumhoefer@wischeesemakersassn. org