During the 1990s, it was popular for municipalities around the world to enter into agreements with private contractors for water and wastewater treatment plants and services. The trend has slowed and lost favor for new systems in urban residential areas, but wastewater treatment for industrial operations remains largely private, and private wastewater treatment agreements are still desired in many suburban areas. Suburbia likes private contracting because it allows developers the chance to build higher density housing in areas where municipalities cannot or will not provide wastewater treatment.
An example of how that works is the Ballantrae Wastewater Treatment Plant at the northernmost edge of greater Toronto, Canada. The plant serves 800 homes in a senior community constructed around a golf course. When the developers decided to build the subdivision, the hamlet of Ballantrae had a population of only about 300 people. The rural community around that hamlet did not have a municipal wastewater treatment plant; every home had its own private well and septic system.
“Because by-law restrictions on lot size existed for a tile bed and septic system, the builder [for the new senior community] performed its own environmental study and built its own wastewater treatment plant. That was the only way to construct high-density housing,” said Eric Todt, owner of Outdoor Enviro Services, Inc., the company that now operates the plant.
The plant was built in 1999 and continues to be managed efficiently under a contractual arrangement. One of the challenges in a situation like this is that “we don’t have a bottomless pit for operation expenses,” Todt explains. Those expenses are covered by the budget for just 800 homeowners.
“The municipal fresh water system is separate from our operation, but just like municipalities everywhere, we’re governed by environmental laws,” Todt adds. However, because of more intense focus and less labor expense, costs are low, and “we can run lean and mean.”
Don Stronge, an operator at the plant, who previously worked for the municipality of York for 38 years, adds, “It’s very different working with financial restraints, but we operate very efficiently.”
One tool that helps is technology. Like most municipal and private wastewater treatment systems, Ballantrae Natural Resource, Inc., the contractor that manages infrastructure for the subdivision, uses a supervisory control and data acquisition system (SCADA) to control the plant. It operates the programmable logic controller (PLC), which controls the sequence and stepping of plant operations. While the plant can run without human beings on site, the SCADA system is continually monitoring what’s going on, and staff is on call 24-hours-a-day, 7-days-a-week. “There’s no rolling over in your bed and going back to sleep when that beeper goes off!” Stronge jokes.
Also, “our staff is very small, so we use essential support companies to help maintain the plant,” Todt says. Using contractors reduces liability, increases speed and reduces costs. “We have computer, instrumentation and mechanical systems, and they all require skilled people to deploy. We have to hire qualified contractors who specialize in pumps, valves and computer systems to fix problems we can’t fix.”
DEPENDING ON THE EXPERTS
Another area where expertise is needed is supply.
“A significant expense is valves and pipes,” Todt says. “But I work with a great distributor,” which allows him to focus on operation and environmental health and safety compliance so that the plant maintains its perfect record. (The Ballantrae plant has never had a reportable environmental incident in its history.)
Both Todt and Stronge stressed how important a distributor is in finding what’s needed quickly and on budget. The main distributor used for the project has extensive experience with local municipalities and uses that experience to find equipment that can be retrofitted with minimal impact, Todt says. Also, “There is two of everything in this plant so if one part goes down, I have a spare.”
For hard-to-locate equipment, Todt finds new sources. For example, he explains a situation in which a valve became obsolete—nobody currently carries repair parts for the valve despite the fact the same kind of plug valve is used in municipal plants throughout North America.
“They don’t even make a seal kit for this valve anymore. But I approached a local company that makes hydraulic seals, and they made up a kit up for us,” said Todt.
Beyond meeting provincial regulations, Todt and Stronge are especially sensitive to the necessity of ensuring every aspect of the treatment plant is operating with minimal environmental impact. Treated water from the plant discharges to a pond on the property, and the site itself is a registered site for the National Audubon Society.
“We get swans, ducks, geese and migratory birds of all kinds. The pond also has koi,” Todt says. One of the ways he measures how the company is minimizing its effect is that these fish “are huge. We know we’re doing a good job of wastewater treatment because all the fish are living.”
The pond water also is used to irrigate the golf course in the summer; in the winter, the discharge is subterranean. “It’s a complete hydrographic cycle,” Stronge says.
The use of treated residuals from wastewater processes (biosolids) are regulated in Ontario by the Ministry of the Environment, and in the U.S. by the Environmental Protection Agency. Meanwhile, local governments on both sides of the 49th parallel determine whether those biosolids can be recycled as fertilizer, incinerated or buried in landfills.
Ninety-nine percent of the valves at the Ballantrae wastewater treatment plant are plug valves; the remainder are ball or gate valves. Generally the valves are made of ductile iron.
Most of the valves in the plant are electrically actuated because they are controlled by the SCADA system to react to changes in sewage levels, temperature and flow rates. Automation is also required to regulate the amount of air that gets to the bio-organisms that are carefully cultivated to treat the water. To be effective, this biota require oxygen and food to live. The bacteria and protozoa consume biodegradable soluble organic contaminants such as fats, sugars and other organic molecules. The precision required to make this happen is possible only with a fully automated system.
Stronge uses his experience with municipalities to show how automation has affected the wastewater treatment facilities. In the past for a city the size of Toronto, “There was a man operating every valve. But when computers came into operation and actuation was automated, the city was able to greatly reduce labor costs.” Even the amount of alum—the coagulant used as a sludge dewatering agent in the plant—is controlled by the computer system, he said.
Private wastewater treatment plants are fulfilling increasingly important functions in the nation’s infrastructure. The purpose of these plants is to make possible subdivisions in rural areas, run commercial facilities in rural areas or protect the environment during oil and gas exploration. Essential ingredients in making these plants economical are automation as well as good suppliers and contractors.