Garden Lane Water Treatment Facility Begins Operations

By Jonathan Kleyer

Portage’s new water treatment plant at the Garden Lane well field has started operations.

Construction for the $5,213,716 facility began last spring. The treatment facility was built to use an indoor gravel and carbon filter system to remove arsenic, iron and manganese from the groundwater supply. The project also included the addition of a new well to the well field.

“We’ve gone to go through a start-up already and then we’ll have the final landscaping work done by June,” commented City Engineer Chris Barnes.

The completed project will put up what the city describes as a “native planting scheme” and tree buffer between the facility and Garden Lane.

Barnes explained that one of the reasons Portage decided to build the treatment plant is because the Environmental Protection Agency lowered the limit on how levels of arsenic allowed in drinking water.

In 2006, the EPA lowered the federal standard for the maximum allowed amount of arsenic in drinking water from 50 parts per billion to 10 parts per billion.

The problem for Portage was that in its water utility system, which has 22 operational groundwater wells, two wells had to be taken out of service because they exceeded the lowered arsenic limit—and a third well was close to the limit.

“We have a few wells that have over 10 parts per billion, so that we either needed to abandon those wells or treat the water. So we chose to build a treatment plant,” Barnes confirmed. “The levels of arsenic aren’t rising. It’s not one of the elements that you would normally see rise, unless you have a contamination problem.”

Portage’s water utility system draws water from the Kalamazoo-Portage and Schoolraft aquifers, and Barnes assured that any arsenic in the water was simply naturally-occurring, not the result of contamination.

As for the other reason Portage chose to build the facility and additional well, Barnes commented, “Our goal as a city is to make this area our central pumping and water supply area. So we wanted to provide some additional capacity.”

Barnes estimated that the new well is going to provide an additional million gallons of water a day.

The engineer joked that explaining how the treatment facility would remove arsenic from the city’s water was going back to high school chemistry.

“The water is pumped up out of the ground, and it’s pumped through a series of four filter vessels that have a combination of different kinds of gravel and rock. Much like a filter system in an aquarium,” Barnes said. “We add chlorine to the water, which combines with the naturally-existing iron, which oxidizes it and turns it into a rust. As it goes through the filter process, the gravel gets smaller and smaller and removes it from the water. In a nutshell, it filters it through sand and gravel and carbon to strip arsenic from the water.”

The reason the plant removes arsenic, iron and manganese is mostly because the process happens to involve all three. Barnes explained that manganese is bound up with the iron in the same manner.

“All of those elements are similar, so they’re often found together,” he said. “We don’t really have much manganese, though.”

He said that there are benefits to going ahead and removing all three, however.

“Removing the iron also helps prevent staining laundry and dishes, which is a good thing,” Barnes commented.

According to information released by the city, the facility’s building was designed to meet general Leadership in Energy and Environmental Design standards by incorporating a number of “green” construction techniques, from pervious pavement and natural interior lighting to storm water management and recycling of the plant process water.