Water Quality Is a Central Focus for Michigan’s Genesee County Communities

In the wake of the Flint Water Crisis, a dozen communities in the city's own Genesee County are now receiving potable water from one of the newest water treatment facilities operating in the nation

Water Quality Is a Central Focus for Michigan’s Genesee County Communities

The reactor chamber of CONTRAFAST. In this chamber, incoming water mixes with previously settled solids to promote flocculation and solids contacting. Chemical addition is also introduced in this process.

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A dozen communities in Genesee County, Michigan, recently began receiving potable water from a new multimillion-dollar water treatment plant in neighboring Lapeer County’s Columbiaville Village.

The $72 million facility, which services more than 200,000 customers, receives water from Lake Huron via the newly-built Karegnondi Water Authority (KWA) pipeline. The pipeline is capable of delivering 125 mgd of raw water, and the plant can treat about 30 mgd.

But not all of the communities that originally committed to use the pipeline will access its water. One of those communities is Flint, Michigan, the county seat and population center in Genesee County.  Flint, along with Genesee County, was a key initiator of the KWA pipeline. But in late November, 2017 Flint instead opted to receive its water from the Great Lakes Water Authority which was created in late 2014, following months of debate on which source to choose.  

Earlier, in April 2014, Flint stopped using treated water from the Detroit water system and began pumping water from the Flint River for the city’s drinking water source.  A lack of corrosion-control chemicals caused the more corrosive river water to damage the city’s water infrastructure, and caused lead to leach into the city’s water system, resulting in a citywide health emergency by exposing Flint residents to toxins.

Emphasis on water safety

With the heightened emphasis on safe potable water following the highly-publicized concerns over water safety in Flint, Genesee County officials have made rigorous efforts to ensure its water meets state and EPA requirements for the communities and residents serviced by the KWA pipeline and the county’s new water treatment plant.

Genesee County Drain Commissioner, Jeff Wright, told the Flint News in November the commission understands the importance of water safety. “Our plant mirrors the first-class treatment process conducted by our previous water supplier, the Great Lake Water Authority, treating the same Lake Huron water.”

Wright described the thorough and deliberate planning, construction and operation of the plant, emphasizing how every action focused on safety and reliability.

Testing took place for four months at the county water treatment plant and multiple locations along the distribution system. To ensure the water is of the highest quality, Genesee County completed its lead and copper testing for 2017 while it was still connected to the Great Lakes Water Authority.

In addition to lead and copper, the county water facility completed a battery of additional water sampling. These tests measured parameters such as temperature, pH, hardness, chlorine, fluoride, aluminum, zinc and sulfates, and many other factors. The tests established a baseline for future water testing.

Plant process

When Genesee County decided to treat its own water and build a new treatment plant, it considered several options for the type of treatment it could use, including conventional treatment, reverse osmosis and microfiltration. County officials chose a conventional treatment plant because they believed it was the best system to deliver the highest quality water to its residents.  

After traveling 67 miles from Lake Huron, the raw water reaches a 150-million-gallon holding pond where the lake water can settle before it is screened and released into the plant.

Central to the performance of the Genesee County Water Treatment Plant is its high-rate sludge thickening clarifier. As early as 2015, the county began testing a clarifying technology called CONTRAFAST, developed by WesTech Engineering, at one of the city of Saginaw’s reservoirs, which also receives water from Lake Huron.

The CONTRAFAST pilot operated like a miniature water treatment plant, pulling water from one of Saginaw's two 90-million-gallon reservoir cells. A filtration pilot column was included as part of the testing to determine filterability of the CONTRAFAST unit effluent.

Testing of the treated water gauged pH levels, turbidity and other factors. The process was designed to assess the effectiveness of the entire treatment process, which Genesee County planned to use in its new plant, and ultimately did select.

“The clarifier utilizes a combination of internal and external solids recirculation, and tube-settling clarification,” says Jeff Easton, WesTech process engineer. “It is capable of running at four times the rate typically used for conventional clarifiers, and produces sludge with as much as 10 percent solids by weight, eliminating the need for a gravity thickener.”  

The entire process takes place in a single basin, reducing a plant’s footprint. It works with this 10-step process:

• Raw water is combined with recirculated sludge and treatment chemicals in a center draft tube;

• A variable-speed impeller mixes the flow at high G-values, accelerating flocculation and densifying the solids;

• Water and densified solids are recirculated within the reactor chamber;

• A high-velocity upflow port prevents settling in the reactor and transfers water to the settling chamber;

• A baffle directs the water to a more quiescent settling area where the solids settle out;

• Tube or plate settlers remove residual solids;

• Effluent launders collect clarified water;

• Dense sludge settles to the basin floor where it is continually scraped and further thickened;

• Thickened solids are continuously recirculated to the draft tube to seed future floc and densify sludge; and

• Periodic blowdown removes solids from the process as needed.

CenTROL Gravity Filters

Once the CONTRAFAST units have clarified the water, it passes through two CenTROL gravity filters in a cluster arrangement. Each CenTROL unit includes four gravity filter cells arranged around a centrally located influent distributor box, and backwash waste control column.

An operating platform on top of the distributor box allows convenient visual inspection of four filter cells from this central location. Inlet weirs within the distributors evenly divide flow between all online filter cells without the use of electro-mechanical flow control systems. Hydraulic flow control through the filter system eliminates potential flow surging providing a consistent high-quality effluent.

Use of a downstream effluent weir system allows the filter system to generate the required backwash supply without the need for additional storage or pumping systems. Backwash of the filter incorporates WesTech’s MULTIWASH Filtration Process, using sustained simultaneous air-water backwashing to return the filter media to like-new condition after each backwash, while minimizing backwash waste generation. Specially designed baffles, situated around the wash troughs, prevent media loss during the backwash process.

Water independence for Genesee communities

The 94,000-square-foot treatment plant, accessory buildings and retention basins, positioned on 80 acres, put Genesee County at the forefront of water supply safety and innovation.

Shortly after the facility opened, Wright told the Division Index (a publication in Michigan) that the pipeline and treatment facility were constructed on time and under budget. He also said that the facility will save hundreds of millions of dollars over the next 30 years; stabilize water rates; ensure the lowest water rates in the Great Lakes region; and provide a solution that will last 100 years.



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