Sunday, January 18, 2009

Milwaukee - Sewer District

The Milwaukee Metropolitan Sewage District (MMSD) is arguably one of the best in the nation. Sewage districts, which span multiple jurisdictions, are forced to navigate difficult waters. Not only are they unable to force regulatory changes within their own boundaries, they often only cover portions of watersheds, leaving sections of waterways that drain into their area of responsibility totally out of their control.

For any sewage district to meet their mandate to treat sewage and act as a steward for waterways, they must forge political alliances between urban and suburban leaders. Two decades after the "Sewer Wars" in Milwaukee, it is clear that those alliances are now treated with great value. Outlying communities no longer threaten to break from the district and money flows into MMSD coffers to pay for infrastructure upgrades.

Before I get into what the MMSD is doing right and where they fall off the wagon, I'd like to give a brief overview of the treatment district, one of the largest in the country. The district covers 411 square miles over six different watersheds and dozens of local jurisdictions. They operate two separate treatment facilities, over 500 million gallons of storage capacity and 300 miles of collector pipe while managing flood control and mitigation for the entire area. Each jurisdiction owns and operates their own sewer pipes that feed into the MMSD collector pipes. Most of this area has separate sanitary and storm sewers, however 27 square miles in the heart of Milwaukee proper and a nearby community utilize combined sewers.

This small area of combined sewers collect so much water during rain storms and snow melts and that they often overwhelm the fixed capacity of the treatment plants. Each of the two plants can treat 300 million gallons of sewage per day but even a single inch of rain can add an additional 450 million gallons of water from the combined sewer area alone. Each storm event also brings additional groundwater infiltration into the 6000 miles of leaky pipes not operated or governed by MMSD.

For decades, rainfall in the Milwaukee area meant sewer overflows. If more water flowed to the treatment plants than they could handle, that excess water, usually a combination of stormwater and sanitary sewage, was discharged into the lake. The 1960's brought an environmental movement that no longer accepted 50-60 overflows per year and a solution was devised.

The decision was made (after much conflict) not to tear up streets in Milwaukee to separate the sanitary and storm sewers. Instead, 520 millions of gallons of storage capacity was built in tunnels burrowed deep beneath the city. The cost of this proposal (after much conflict) was shared between the city and suburbs.

$3 billion later, MMSD has nearly eliminated sewer overflows. Thanks to amiable communication between interested parties and ever evolving technological solutions, treatment efficiencies are increasing. Suburban communities have recently settled a lawsuit that will force them to upgrade their leaky pipes. Groundwater that flows into these pipes, greatly increases the risk of overflow and cost of treatment. MMSD operates hazardous waste collection as well as pharmaceutical collection as a way of avoiding costly treatment upgrades.

For over 80 years, the excess bacteria from secondary treatment is dried to create Milorganite, a popular commercial fertilizer. They sell 41,000 tons a year. The settled waste from primary treatment is anaerobically digested and produces $1.9 million worth of biogas a year. These programs are encouraged by the Wisconsin Beneficial Reuse Program which should act as a model for the nation.

MMSD has a website that shows they are striving for transparency. The have online tools showing sewage flow and treatment as well as river health advisories. Click on the link and you'll be able to find out how much sewage is flowing into each treatment plant at this very moment. All very cool stuff, if your city doesn't have informational tools like this, agitate!

But all is not well in metro Milwaukee. A recent watershed-by-watershed analysis revealed that most sampling sites in the watershed regularly exceeded acceptable limits for most pollutants, especially fecal coliform. A study by MMSD showed that only a fraction of this bacteria is now a result of sewage overflows. A vast majority of water quality problems are caused by runoff. The only place in the district with improved water quality is in the combined sewer area, where stormwater is treated to the same level as sanitary sewage.

This is a problem facing (or will soon face) all major sewage districts. They have exhausted the big fixes and are still left with big problems. We are entering the area of massively distributed little fixes. Rain barrels, green roofs, rain gardens and increased foliage are of little consequence if they are taken by their minuscule increments, but on a massive scale, they can have a massive effect.

MMSD knows this and to move in that direction, they have sold 10,000 rain barrels at-cost to district residents and subsidize rain garden plants. But they are unable to create the necessary vast scale of implementation under their current operating structure. Because they don't bill customers directly, they have no way to attach incentives to little solutions. To demonstrate their weak political position, it was only after years of cajoling that an informal agreement was put into place to limit the additional runoff caused by new development. Without legal authority, how can they possibly get communities to require rain barrel installation? Or implement green roof requirements?

I'm not sure if it makes more sense for the MMSD to evolve into an organization with some regulatory punch or if an entirely new body with a different mandate should be created. Since water-body quality is affected by activities throughout the watershed, one thing is overwhelmingly clear: effective management must be done at the watershed scale and it must have political authority. Those at the bottom of a river must have some say over what goes into the river at the top of it.

We can no longer rely on massive infrastructure solutions to clean up the mess we make. The most efficient and effective way to fix a problem is at its source. If that means new laws mandating rain barrels and green roofs, so bit it. If putting these new laws on the books takes a new political jurisdiction, let's make it.

1 comment:

  1. Very interesting article, I live in Milwaukee and didn't know a lot of this!