Highland Park plans to break ground Friday on a $30 million expansion of its water plant, a project in the pipeline for 15 years. The Lake Michigan water served to more than 60,000 north suburban customers will be cleaner, more abundant — and, naturally, more expensive.
Officials say they have no estimate of just how much more consumers will pay. They tout current rates that are among the lowest in the state, but point out that upgrading an 85-year-old plant to a modern filtration system with more capacity is not cheap. The new technology is expected to be operational by mid-2014, with the project scheduled to be largely completed by the end of that year.
Highland Park's water plant supplies Deerfield, Lincolnshire, Bannockburn, Fort Sheridan, and the Glenbrook Sanitary District, which is the unincorporated district surrounding Northbrook Court. Its current sand-and-gravel filtration and chemical treatment is similar to what most municipal water plants use.
But many in the water industry see "membrane filtration" as the wave of the future. One of them is Don Jensen, Highland Park's water plant superintendent. He calls the technology "the gold standard" for drinking water purification.
Rather than drawing water through layers of sand and rock to separate illness-spawning pathogens, it's drawn through cylindrical membrane tubes. Inside are hundreds of smaller straw-like tubes, each with tiny pores. Water is pulled through the ends of the tubes through a vacuum process, and the membranes filter out bacterial, viral and other pathogens.
Highland Park would be the eighth municipal water plant in Illinois to install membranes, according to David Cook, of the Illinois Environmental Protection Agency's public water supply division. Lake Forest was first, in 2004, followed by six smaller downstate cities.
For decades, sand filtration worked fine, along with chlorine treatment. In most cases it still does, and meets all state and federal requirements. Filtration and chemical treatment was originally targeted at preventing typhus and cholera, which became an increasing fear in the late 1800s and early 1900s as cities grew and struggled to prevent sanitary waste from mingling with drinking water.
But a new fear arose in 1993, after an outbreak in Milwaukee sickened an estimated 400,000 people. The culprit was cryptosporidium — a protozoan pathogen that slipped through the conventional treatment process through an unusual confluence of events. The incident shook both water providers and regulators.
There have been no known cases reported in Highland Park, and a monthly test over an 18-month period found no sign of the pathogen in local Lake Michigan water samples, Jensen said.
"But not detecting is not proof of absence. We know they're in the lake, we just didn't see them," Jensen said, noting the test was merely a snapshot of a particular water sample. "We have to assume they're there."
He'd rather err on the side of caution.
"This is an insurance policy against those pathogens," Jensen said.
But it's not cheap.
Each membrane tube costs between $400 to $450, and Highland Park's plant expects to use 3,500 of them. Jensen estimates the membranes have about a seven- to 10-year lifespan. Since the technology is proprietary, the city is entering into a marriage with its German provider, Siemens.
Kenosha, Wis. was among the first to adopt membrane technology. In addition to a sand filtration plant with a 20 million gallon per day capacity, it opened an 18 mgd membrane facility in 1998, also using Siemens equipment. While its process is slightly different than what Highland Park expects to use, the membranes are essentially the same.
But the process hasn't come without its share of unexpected hurdles, said Roger Field, director of water production in Kenosha.
That plant found the membranes lasted fewer years than expected. The original membranes lasted from 1998 until 2006. The second set was replaced three years later, in 2009. And now, four years after that, Kenosha is looking to replace them again, Field said.
Plant output has also been an issue, he added. When the membranes were first installed, there were two "trains" of filters, which had been estimated to fulfill its needs. When it turned out to be insufficient, the city purchased a third train.
"We're still trying to make that flow that they guaranteed us," Field said.
Jensen said Highland Park has learned from its neighbors and planned conservatively, so he doesn't expect similar difficulties.