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Treatment Process

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The four stages of cleaning wastewater

Wastewater cleaning process

1. Screening - Large and small objects are removed, like towels, sand, and gravel.

2. Primary Clarification - Grease and oil float to the top of large settling tanks. Solids sink to the bottom and are collected to make energy.

3. Biological Treatment - Microscopic organisms, "bugs", break down organic material. The bugs we use for cleaning wastewater are famous! When they're done doing their jobs in the water reclamation facilities, we dry them out and turn them into Milorganite®, a slow-release fertilizer sold nationwide, trusted and used by lawn and gardening experts since 1926.

4. Disinfection - Disease-causing organisms are killed by chemicals that are then neutralized. Clean water is returned to Lake Michigan.

Environmental Protection Agency (EPA) Goal for capturing and cleaning wastewater = 85%

MMSD's performance since 1994 = 98.4%

Here's how we're doing so far this year:

2021 Volume treated

Gallons Treated: 19,846,000,000

Gallons Overflowed: 0

Total Gallons: 19,846,000,000

MMSD % Treated: 100.00%



mmsd percent capture clean graphic

Since 1994, we've captured and cleaned more than

1.9 Trillion gallons of water and wastewater