Background l The Technology l Effluent l Biosolids l Green Roof l Honored for Excellence

Background
From 1989 until constructing its own Water Reclamation Facility (WRF) in 2006, the Shakopee Mdewakanton Sioux Community utilized an aging regional governmental sanitary waste treatment facility for its sanitary sewer needs. That system discharges effluent directly into the Minnesota River. From a position of weakness, the SMSC had to negotiate for additional sewer units each time new housing or enterprise additions were planned. Designing, constructing, and operating a tribal WRF is a very important achievement in strengthening self-determination and self-governance. Not only did this project strengthen sovereignty, but it also brought state-of-the-art wastewater treatment to the United States and created additional resources for the SMSC. Use of treated effluent for irrigation has reduced groundwater withdrawal by the SMSC by approximately 35,000,000 gallons a year.

Construction on the facility began in February 2005 and took 18 months to complete on an expedited schedule. Principal designer was Bolton & Menk, Inc., Environmental Services Division, Mankato, Minnesota. Architect Plus of Faribault, Minnesota, designed the building. General contractor was Rice Lake Construction Group, Deerwood, Minnesota.

The SMSC opened the WRF on trust lands on August 18, 2006. The WRF treats wastewater from all tribal residences and Community enterprises, including Mystic Lake Casino Hotel, located south of County Road 42 in Scott County, Minnesota.

"Having our own water reclamation facility increases sovereignty, facilitates future planning, and decreases dependence on other jurisdictions," said SMSC Chairman Stanley R. Crooks.

The unique characteristics of the WRF are the direct result of the Community’s dedication to protecting and preserving the environment.

Facts About the Facility

The Technology
The SMSC Water Reclamation Facility is one of less than a dozen in the United States which utilizes BAF (Biologically Aerated Filtration) technology, a continuous flow process developed in Europe and recently imported into the United States. In Europe land is at a premium and water quality standards are very high. In essence, millions of tiny styrofoam beads provide a home for bacteria which eat suspended and dissolved solids in the wastewater.

The WRF provides primary treatment using screens, a vortex grit removal system, and clarification to remove solids. Secondary and tertiary treatments take place in the BAFs with post tertiary treatment using membrane microfiltration and disinfection. The combination of the BAFs and the membrane microfiltration is a unique application of these technologies. The membrane microfiltration followed by ultraviolet disinfection returns the water to the environment at drinking water quality.

Control of the WRF is by a computer-based system which monitors all equipment. Redundant systems assure continuation of services. The support facilities for the plant include a standby diesel power generator in the event of a loss of electrical power. An onsite laboratory allows the performance of required testing, assuring proper operation of the facility. Room for future growth was also built into the facility.

High quality air scrubbers inside the building minimize odor outside the building. Noise dampening materials and construction processes were also used to keep sound from WRF operations to a minimum outside the building.

Effluent
Typically, effluent, clean treated water that flows out of a treatment facility, is discharged to a river or other public body of water. In the case of the SMSC’s facility, the effluent is routed through two wetlands within the Community before flowing into a large irrigation pond. Water from the pond is then used to irrigate The Meadows at Mystic Lake golf course, as well as other areas of the reservation. Water discharged from the facility contains less dissolved solids than the water already present in the wetlands and meets drinking water standards for surface water use. During the irrigation season, very little effluent from the WRF exits SMSC land, eliminating downstream impacts.

On January 22, 2007, the discharge of treated water from the WRF to the wetlands took place for the first time. The effluent traveled through a pipe to the wetlands west of Dakotah Meadows RV Park and Mini Storage. Rigorous standards for water quality were met before discharge. Wildlife flocked to the site of the effluent release, relishing the warm (57 degree Fahrenheit) water during the cold Minnesota winter when most other water bodies are frozen. Open water all winter in the wetlands provides a home for minnows which are eagerly devoured by water fowl. Even during warm weather the wetlands provide a home for Canadian geese, muskrats, mallards, and others.

Groundwater is the sole source of drinking water in Scott County, where the SMSC is located. Region-wide groundwater demand is increasing, with limited groundwater available. The Community is considering injecting treated effluent from the WRF into the aquifer for use in the future. The Community has completed a bench-scale study and is proceeding with additional research. This project has generated nation-wide interest, and a technical committee of tribal, federal, and state agencies has been assembled to monitor the full-scale pilot study. Removal of emerging contaminants including endocrine disruptors and pharmaceuticals are a primary goal of the research. The State of New Jersey is also studying a similar process, but the Community is the only tribal government currently active in this process. Technology developed here will be readily transferable nationwide.

Biosolids
As part of the water reclamation process, there are solids remaining after the water is removed and treated. These biosolids are pressed and dried for use as fertilizer in a drying process that is the first of its kind in the United States.

Influent from SMSC facilities and residents flow into the WRF for treatment. Inorganic solid materials are removed for transfer to a solid waste dump in the initial treatment operations. Organic matter, called biosolids, which remain are pumped to the biosolid room for treatment. A polymer, or coagulant, is then added to help de-water the materials.

Next, equipment removes the water from the sludge in two processes. The first is a belt press, and the second is a large oven. The drying process, which takes 30-32 hours, also sterilizes the biosolids, which are then placed into large bags for storage and transport. The drying process converts the biosolids to a solid product with a water content less than 8%. The SMSC uses these Class A biosolids on The Meadows at Mystic Lake and agricultural lands within the Community. The biosolids are also mixed with mulch and used on flower beds and landscaping throughout the Community. It may also provide a future fuel source in waste-to-energy recovery facilities such as the Koda Energy project which will be operational in December 2008.

Green Roof
During the design phase of the WRF, the SMSC found that it did not have available land to accommodate the necessary size of the facility and sufficient storm water ponding to handle the project’s runoff. A vegetated green roof was suggested by the SMSC Business Council to allow the project to proceed by storing rainwater on the building itself, reducing land impacts and pollution. The green roof system disperses significant amounts of water back into the atmosphere through evaporation and transpiration.

The 30,200 square foot, vegetated roof hosts over 45,000 plants which themselves have become habitat for pollinators, grasshoppers, spiders, and other insects. Seeds for native prairie grasses and flowers were strewn to fill in the spaces between plants, creating a lush vegetative roof. During dry spells, the plant life on the roof is supported using reclaimed wastewater from the treatment process itself, yet another benefit of the high level of treatment the facility provides.

A Green Roof reduces the total storm water runoff from the building. It also reduces erosion and improves water quality. The green roof also has an extended roof life because it is protected from ultraviolet radiation. A typical roof will last about 12 years; the green roof is designed to last 50 years.

The green roof also simplifies temperature management inside the facility, because it lowers the temperature inside the building. By efficiently managing heating and cooling, energy usage is reduced. Most of the WRF, though not air-conditioned, remains comfortable throughout the year, even during the hot months of summer. The building itself, aside from the superior treatment process, is designed to produce minimum environmental impact on the site and the surrounding area.

Part of the Green Roof is being used for research to determine some of the efficiencies of a Midwestern green roof. These studies may make green roofs a more marketable building option to other governments and private industries in the future.

The Community has hosted numerous tours of the WRF, including groups of government officials, tribal leaders, tribal public works departments, foreign journalists, and American Indian students. The highlight of these tours is generally the visit to the green roof.

The SMSC is also building the largest green roof in the Midwest at 32,648 square feet on its new Dakotah! Sport and Fitness Ice Arena. The SMSC’s second sheet of ice will open in October 2008.

Honored for Excellence
The Shakopee Mdewakanton Sioux Community Water Reclamation Facility has been honored by three organizations for its excellence. The Minnesota American Council on Engineering Companies (ACEC) presented the SMSC with a Grand Award at a banquet held January 26, 2007. The SMSC project won one of nine Grand Awards for the best overall engineering achievement. The ACEC competition recognizes projects that demonstrate a high degree of achievement, value, and ingenuity. For more than 40 years, this competition has awarded uniqueness and originality; future value to the engineering profession and perception by the public; social, economic, and sustainable development considerations; complexity; and successful fulfillment of client/owner’s needs, including schedule and budget.

The Minnesota Society of Professional Engineers (MSPE) 2007 Seven Wonders of Engineering Award was presented to the SMSC February 23, 2007, in Bloomington, Minnesota, as part of MSPE’s Engineers Week celebration. Entries were judged on the engineering methods, systems, and skills utilized by the project team; the project’s advancement of the engineering profession; the complexity of the project and how the project team overcame this complexity; the significance of the project to society; and the extent to which the entry meets the needs of the market, client, or owner.

The SMSC facility was also awarded the Minnesota Governor’s Award for Excellence in Waste and Pollution Prevention. The 16th annual award was presented during a banquet on February 28, 2007. The award honors superior environmental achievement by Minnesota non-profit organizations, businesses, and private institutions for programs or projects that benefit the environment by reducing or eliminating wastes and pollutants at the source. Award winners selected by the Minnesota Pollution Control Agency for this award are leaders at the highest level of environmental achievement.