Friday, April 11, 2008

April Showers Bring MMSD Sewage Overflows

Ah, Springtime!

April showers bring May flowers... and sewage dumping.

From the Milwaukee Journal Sentinel:

Heavy rains Tuesday and Thursday resulted in combined sewer overflows to urban rivers and Lake Michigan beginning Thursday night, and prompted the Milwaukee Metropolitan Sewerage District to begin blending partially treated wastewater with fully treated flows at the Jones Island treatment plant, district officials said.

It was the first combined sewer overflow in central Milwaukee and Shorewood this year.

Blending was necessary to prevent filling of the deep tunnel storage system, causing separate sanitary sewer overflows in the rest of the district's service area, district Executive Director Kevin Shafer said. It was the first time blending had been needed since May 2004.

The actions came as heavy rain fell in the area for the second time in three days, bringing rainfall totals in some places during that period to over 3 inches. The National Weather Service in Sullivan issued flood warnings for areas of southeastern Wisconsin, including Rock, Waukesha, Milwaukee and Racine counties.

Shafer ordered gates from combined sanitary and storm sewers to the deep tunnel storage system closed at 6:05 p.m.

The action was taken to reserve adequate space in the quickly filling tunnel for sewage from separate sanitary sewers in the rest of the district's service area. Sanitary sewer overflows generally are prohibited under the district's state permit.

At the time the combined sewer overflows began, an additional half-inch of rain was forecast between 6 p.m. and midnight in Milwaukee County, Shafer said.

Allowing combined sewer overflows during heavy rainstorms prevents sewers from backing up in basements, Shafer said. The district is allowed up to six combined sewer overflows in a year.

Blending began about 8:15 p.m. In a heavy rain, the district is allowed to divert up to 20% of the wastewater flow around a secondary treatment stage and then blend that volume with fully treated flows before discharging it to the lake.

...A brief sanitary sewer overflow, the first one of the year, was reported at 5:09 p.m. at Bay View Park in St. Francis.

I don't like the term "blending" used in conjunction with sewage.

"Blending" makes me think of a pitcher of margaritas, not wastewater.

Raw sewage wasn't dumped into the lake, but the water discharged was not fully treated. Obviously, it's not a good situation.

Still, you can't have sewers backing up into basements. That possibly poses a greater health risk than the dumping of the "blend" into the lake.

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