Water treatment plant operator fined $151,552
$4,700 daily penalty imposed for wastewater discharge with too much bacteria
The Milwaukee Metropolitan Sewerage District is penalizing the private operator of its regional sewage treatment plants more than $4,700 a day for failing to comply with contract limits on wastewater discharges from the South Shore plant in Oak Creek, district officials said.
Veolia Water Milwaukee LLC has been unable to control the growth of nuisance bacteria in large, open basins used in the treatment process at South Shore since June, records show.
As a result, excessive numbers of the unwanted microbes — known as filamentous bacteria — have disrupted treatment and cut treatment capacity there since July 12.
Wastewater discharges from the plant in July exceeded contract limits for fecal bacteria, ammonia and two other pollutants, Veolia Water Milwaukee General Manager Scott Royer said.
Amounts of those pollutants in plant discharges, however, were well below state permit limits set to protect Lake Michigan water quality, according to district officials.
The financial penalty was imposed Aug. 4 and will amount to $151,552 by Labor Day, MMSD contract compliance manager Patrick Obenauf said in an Aug. 23 letter to Royer.
The loss of treatment capacity substantially reduced the plant’s ability to deal with heavy flows of wastewater during rain storms, and increased the risk of sewer overflows to local rivers and Lake Michigan, Obenauf said in an interview.
MMSD is authorized under a state discharge permit to treat up to a maximum of 300 million gallons a day of wastewater at South Shore. The plant is unable to process more than 120 mgd — only 40% of its full capacity — at this time, according to district records released to the Milwaukee Journal Sentinel.
South Shore’s capacity was cut to 190 mgd on July 12, restored to 230 mgd on July 18, and reduced to 120 mgd on Aug. 16 due to the ongoing problem. It remained that low as of Friday.
All but one of the pollutant loads in treated wastewater discharged to the lake had dropped below stringent contract limits as of this week, but Veolia will violate its performance standard for ammonia in August, according to Obenauf and Royer.
The district has established high standards in the contract with Veolia, according to Obenauf.
“These standards are a part of helping to protect our region’s water resources,” he said.
Filamentous bacteria show up at South Shore in large numbers each summer, but the nuisance microbes have never been this persistent or disrupted treatment to this extent in the past, the officials said.
So MMSD is investigating whether there might have been recent changes in wastewater discharged by a local industry into the regional collection system that could explain their tenacious growth despite efforts to get rid of them.
MMSD laboratory tests of sewage moving through the early stages of treatment at the South Shore plant show there are patterns of abrupt changes in the contents.
“Frequently, on Monday evenings,” Royer said. These patterns of changes in wastewater cause levels of dissolved oxygen to plummet and create conditions in which the nuisance microbes thrive, he said.
Desirable bacteria and other microbes routinely used to digest organic waste in sewage do their job, then settle to the bottom of treatment basins where they compact together for easy removal. This enables plant operators to drain a basin and divert the wastewater to the next step in the treatment process.
But the filamentous bacteria grow in long strands, or threads, with more surface area than the desirable bacteria. They float in the wastewater and resist both settling to the bottom and compaction.
In July, the company exceeded contract performance limits for suspended solids, ammonia, fecal bacteria and biochemical oxygen demand, or BOD, in South Shore wastewater discharges to Lake Michigan.
BOD is a measure of organic material in wastewater. It is the amount of dissolved oxygen in water used by bacteria as they consume the waste.
Veolia Water Milwaukee has operated the district’s Jones Island and South Shore sewage treatment plants, regional sewers, deep tunnel and Milorganite fertilizer factory since March 2008.
MMSD is the largest publicly owned wastewater treatment system under private operating contract in the United States.
Veolia Water Milwaukee’s parent company is Veolia Water North America, a division of Parisbased Veolia Environment.
In June of 2016, the district’s commission approved a 10-year extension for Veolia Water starting March 1, 2018. The new contract will pay the Paris-based company at least $500 million over 10 years.
Apart from the contract, MMSD manages an industrial waste compliance program, laboratory, water quality research, and Milorganite sales and marketing.