Not only is water quality a growing concern throughout the United States, but so too is water efficiency, with many American communities scrambling to find ways to conserve what is becoming an increasingly precious resource.
Doetsch Environmental Services, a Warren, Mich.-based full-service environmental company, has pioneered an innovative continuous operation process that utilizes recycled sewer water in its cleaning operations and requires no by-pass pumping.
The company has constructed a system in-house whereby the company has taken combination sewer cleaner technology and stretched it onto two trailers — one houses the vacuum equipment and stores debris while the other houses the final filtration, as well as the high-pressure water pump and hose reel.
During the vacuuming process, solids are separated from the liquid. The liquid goes through several stages of filtration until it’s usable to be put back into the high-pressure pump and injected back into the sewer.
“We started focusing on the environment before ‘green’ became such a buzzword,” notes Joe Schotthoefer, a fifth-generation manager at the 112-year-old company. The company’s services focus on inspection and wet and dry cleaning for such jobs as oil spills, hazardous waste, solid waste and sewer lines.
Doetsch Environmental Services is a rare breed in the industry — not only has it survived and thrived throughout economic fluctuations for more than a century and remains family-owned, but the company has introduced cutting-edge technologies to the marketplace it serves, including municipalities, manufacturing facilities, power plants, foundries, chemical plants and refineries.
For example, Doetsch Environmental Services was the first in Michigan to introduce an electric sewer machine in the late 1920s when sewer cleaning was done by a man entering a manhole with a bucket.
The company then automated the system by attaching a bucket to a cable and anchoring it to the manhole to pick up and remove debris.
In the 1970s, Doetsch Environmental Services introduced hydraulic sewer cleaning to Michigan through the use of combination machines.
Now the company is attracting attention with its latest process of using recycled sewer water, which addresses what has become a dire situation in many water-starved regions throughout the United States that are embracing ways to conserve water.
Large-diameter or large bore sewer pipe cleaning has become a growing market, shaped by the increasing number of federal regulations spawned by the Clean Water Act and the aging of the nation’s underground infrastructure, creating a need for greater maintenance and repair — and ultimately replacement.
With water being a key component in large-diameter pipe cleaning, the ability to use it in such a way that conserves it while getting the job done has enabled Doetsch Environmental Services to offer a niche service.
“There isn’t specific equipment to fit this need for cleaning,” Schotthoefer notes, adding that to date, the process has been labor intensive.
“In the past, the only way to tackle such a job was to adapt production equipment,” he adds. “We took a look at the inefficiencies by doing this and from that developed the equipment we currently use.”
Those inefficiencies focused on safety and labor-intensive tasks that have traditionally been “incredibly slow,” Schotthoefer says.
Schotthoefer concedes that like most pipe cleaning operations, the job has seemed much easier by connecting a supply line to a fire hydrant.
But the need to ‘go green’ was becoming increasingly apparent.
On a typical day, Doetsch Environmental Services would use more than 120,000 gals of water in its operations in order to meet the requirements of increased water flows for pipes exceeding 36 in. in diameter. But that water use also increases the amount of greenhouse gases being used in the traditional process.
In Doetsch Environmental Service’s new process, “We’re not using potable water to clean with,” Schotthoefer says. “And we’re not adding water back into the system that has to be treated again. We’re essentially operating a ‘mini’ wastewater treatment plant, putting cleaner water back.”
The new process also addresses an access issue that has been a characteristic industry challenge.
“Typically, the amount of water we require can’t always be pulled from hydrants without infrastructure damage,” Schotthoefer notes.
In using its new system on a particular job, employees from Doetsch Environmental first conduct a site survey, assessing the sewer segments in question as far as the amount of debris and what should be removed at that point.
“We set up our mobile operation and we would begin by vacuuming water to start the recycling process,” says Schotthoefer. “Once our tanks are full, we are ready to operate. This is a high-pressure water jetting operation whereas the hose will traverse down the sewer pipe to a given distance and then we will retract it.
“As we retract the high-pressure hose with the cleaning head, it will bring material back to the access point, which is typically a manhole that is already installed. We are working with the accesses that are given to us. There isn’t any pre-construction that needs to happen for our process.”
The process repeats itself as the cleaning head travels further to bring the material back. The material is put into a dewatering hopper and at some point during the cleaning operation, it can be unhooked and moved away and another debris hopper is put in its place.
“Once we’re finally completed, then we will use either a camera or sonar operation with which to verify cleanliness and verify capacity has been restored to this particular segment,” Schotthoefer says.
The benefits of Doetsch’s new system to its clients have been numerous.
Many urban cities treat all of their stormwater because of the contaminants that the water picks up during run-off, Schotthoefer notes.
“They need to treat it before they can discharge it into a riparian waterway,” he says. “Our cleaning process is useful in this regard. While we are removing debris from these large pipes, we are restoring capacity so they have more storage.
“If it backs up during a rain event, they have a bit more time to treat this water and discharge treated water.”
For some municipalities, it’s a challenge to get water to the treatment plant fast enough during a rain event.
“So the whole system backs up,” Schotthoefer says. “These systems are built to allow them to overflow — if there’s too much water in the system and it’s a river town or near the lake, that’s where they deposit it without wet weather storage.”
But sometimes, such as in the case of combined sewer overflows (CSOs), there’s a lot more being discharged to the water bodies than stormwater, such as untreated raw sewage.
Another benefit is a savings of time and money — the latter being a major concern in today’s economic conditions.
“With the conventional method of sewer cleaning, in order to make a portion of the system work, you would typically take that portion out of service and use a by-pass pump, a practice that is cost-prohibitive and involves the possible interruption of traffic,” says Schotthoefer. “Our process allows the work to be done in live conditions, without having to take sewer segments out of service.”
Carol Brzozowski is a freelance journalist based in Coral Springs, Fla. She has written about the industrial cleaning industry for more than 15 years and is a member of the Society of Environmental Journalists.