CHICAGO — Somewhere between 1.28-gpf and 0.0-gpf, solid waste stops flowing down the drain. The plumbing industry doesn’t know what that point might be and its efforts to find out have stalled. The Plumbing Efficiency Research Coalition has been trying for the last couple of years to start a study of drainline carry of solid wastes in commercial buildings. The coalition, however, can’t get adequate funding for the study.
According to a recent solicitation of donations by PERC member the Alliance for Water Efficiency, the coalition has only raised $20,000 out of a minimum of $170,000 needed to begin the study.
PERC members include AWE, Plumbing-Heating-Cooling Contractors – National Association, Plumbing Manufacturers International, the International Code Council and the International Association of Plumbing & Mechanical Officials.
The test proposal calls for runs as long as 300-ft. to mimic a worst-case scenario in a commercial or institutional building. The test protocol also calls for flushes that vary from 1.6 to 1.28 to 0.8-gpf, varying flushes of liquid only and solid waste, and loadings of varying amounts of Miso paste filling in for actual solid waste.
The issue the plumbing industry is facing is data-free anecdotes that water-conserving toilets don’t work or cause problems down the drainline. Bill Gauley, P.Eng., principal at Veritec Consulting Inc., Mississauga, Ontario, said that every time he hears such a tale, he tries to get to the source to get data. None ever exists.
A number of years ago, CONTRACTOR picked up a story from the Augusta Chronicle newspaper that quoted Augusta, Ga., water company officials stating that low-flow toilets were creating “super sewage.” Gauley, co-creator of the Maximum Performance Test for low-flush toilets, said the arithmetic doesn’t add up.
“On the website www.idcide.com/citydata/ga/augusta.htm, it states that the population of Augusta is 194,149. I have no idea if this is accurate,” Gauley said. “With a peak day demand of 54.3 million gallons per day, this equates to a per capita demand of about 280 gallons per day. Now I know that this demand includes both residential and non-residential demands, but given the fact that the use of inefficient toilets would equate to about 32-GCD and efficient toilets would equate to about 15-GCD, this means the use of efficient toilets would decrease per capita demand by about 17-GCD — or about 6%. And this is if everyone in town had switched to efficient toilets. I would expect that more than 50% of this peak day demand is actually related to irrigation.”
The newspaper article also quoted water company officials saying that sewage coming into the treatment plant contained 300 PPM of solids and biota that require oxidation instead of the usual 200 PPM.
“I don’t know the details of the residential/non-residential mix in Augusta, but it is not uncommon for a small city to have gross per capita demands of somewhere around 130-GCD,” Gauley said. “Again, if everyone in town switched to efficient toilets, the demand would drop by about 17-GCD to approximately 113-GCD. A decrease of 17-GCD equals about a 13% reduction in total water demands and, one would assume, wastewater flows. How could this cause an increase in sewage concentration from 200 PPM to 300 PPM?”
Anecdotal grousing about low-flow toilets and a lack of data were the reasons why PERC decided to study drainline carry as its first research project, said Barb Higgens, executive director, Plumbing Manufacturers International.
The $170,000 price tag is “… the minimum with our revised work plan,” said Pete DeMarco, director of special programs, IAPMO.
“The first work plan was three-phase and a million dollars. PERC had the bad timing of its creation just when the economy was starting to go sour and government funding for these things was drying up. So we pulled our horns back and created a revised work plan of more limited scope and with a price that makes it easier to talk to government officials.”
DeMarco pointed out that with the advent of HETs and, eventually, HETs that are flushed with graywater, plumbing systems will reach a tipping point beyond which sewage no longer goes down the drain. The industry doesn’t know what that point is. Gauley reiterated that he and his collaborator, John Koeller, Koeller & Co., Yorba Linda, Calif., have recommended that non-residential buildings use only 1.6-gpf toilets because such buildings often don’t have supplemental flows, such as bathing, cooking or laundry, to move waste down the drain.
PERC will likely have the research done in Australia by a related organization that already has a test stand in place. Last December, PERC and the Australasian Scientific Review of Reduction of Flows on Plumbing and Drainage Systems (ASFlow) Committee signed a memorandum of understanding at the U.S. Environmental Protection Agency headquarters in Washington. Like PERC, ASFlow is working on research programs to investigate the impact of reduced water flows in sanitary drains resulting from reductions in water use from plumbing fixtures and fittings, appliances and commercial and institutional equipment.
Nevertheless, the lack of funding remains a problem. Higgens said that one of her manufacturer members has volunteered to pay for part of the research. It was never PERC’s intent to ask PMI manufacturer members to pay for the research, Higgens said, because naysayers in the public will say that manufacturers rigged the results if the research doesn’t confirm the complainants’ preconceived notions. Given that one manufacturer has volunteered, however, PMI will float the idea to its members.
PERC doesn’t want to wait until there’s a highly visible failure in a commercial or institutional building that forces the issue, DeMarco noted.
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