Research Paper

Beaumont's Natural Wastewater Treatment Plant

In 1985 the EPA issued new standards for wastewater discharge. The city of Beaumont, Texas knew that their current method of effluent treatment would not meet the new standards. After considering several very expensive options the city decide to build an artificial wetland onto a current marsh near the city. Eight minimarshes, 600 acres, and the original marsh, 300 acres, now make up an area known as Cattail Marsh. The marsh helps the city meet Federal regulations that prohibit net losses of wetlands acreage.

How it Works
The fact that wetlands clean water is not a new technology, but actually putting this natural phenomenon to work as been done only within the past ten years. The ability to clean the water is very dependent on agitation of the water which in turn increases the oxygen supply. This is accomplished by wind, rain, fish, birds, other animals and a small motor boat with large propellers called Go Devils.

Many of the cells contain bulrushes that absorb atmospheric gasses through the stems for food. Uniquely, the oxygen travels down to the roots and is released into the water which also increases the oxygen content of the water. This high oxygen content water sustains the many animals and bacteria used in the purification processes. Other plants floating on the water capture the ammonia from the effluent and store it within the plant. As the plants die, they accumulate on the bottom serving as a food source for the bacteria that help remove ammonia, nitrogen, phosphates and heavy metals.

The Treatment Process
Wastewater from the city passes through a treatment plant before it goes to the marsh. In the treatment plant the wastewater is clarified . Then, the water is passed through a biological sludge that removes many contaminating chemicals. After this process, the water drains into the first cell of Cattail Marsh. The level of each cell is lower than the one before it, so that gravity
pulls the water through all eight marshes for treatment. The treated effluent water is then discharged into Hildebrandt Bayou.

The first cell of the marsh is used to oxygenate the water and reduce the ammonia levels. Few plants were added to this area so that wind, rain, and animals could churn up the water. This open area attracts birds, and the birds brought in various species of fish. This cell was stocked with gambusia, a minnow sized fish that eats mosquito larva. By eating the larva, the fish also help solve a summertime problem of mosquitoes. The second cell was densely planted with California bulrushes. They have naturalized into clumps that serve as nurseries for fish and birds. This nursery works well as long as the water level in the cell remains fairly constant. The third cell is open water and is about eight feet deep in most areas. Most plants cannot reach that deep to take root so the area has few plants. Oxygenation is the goal of this cell. The fourth cell has clumps of cattails that were introduced by the birds. Officials would like to get rid of them; they are messy plants. Consequently, the area has to be cleaned of debris often. The rushes and other plants in this cell grow thick quickly and thus do not work efficiently. About every ten years this cell must be drained so that the plants can be cut just above the soil line. After the cut, the plants grow rapidly and provide oxygen to the water as well as removing other effluent gasses from the water. It is estimated that the plants will have to be cut every ten years.

The original marsh, Willow Marsh, is at the end of the eight cells. It is thick with trees and native grasses. This marsh was originally dry during the summers and to duplicate this natural process, Willow Marsh is drained during the summer to allow native grasses to regenerate. This area is a wildlife preserve that is open to the public.

Results of the Marsh
Water leaving Cattail Marsh is cleaner than Beaumont's municipal water supply, and the construction of the project was estimated at 13.5 million. This is five million cheaper than any of the alternatives considered by the city. Because it is a natural structure using gravity to move the water, there are few mechanical items to break, and fewer employees are needed to run it. This lowers the cost of operating the facility. The wetlands have brought Beaumont a fair amount of ecotourism and recreational opportunities. Visitors easily can count 40 separate species of birds on any given day. More than eight miles of levee trails can be used by bicycles, runners, hikers and riding horses. Other cities in Texas and around the country are using this method of wastewater treatment. They are finding that is very cost effective, and it satisfies federal regulations on wetland conservation.

Field Trips to Cattail Marsh
To get to Cattail Marsh turn south off Interstate 10 at Walden Road.
Follow Walden Road to Tyrell Park.
The marsh is about a mile south inside the park.
Take the left Y and turn left into the marsh at the sign.
The park is open from 7 a.m. until 5 p.m. daily and a biologist is available for school field trips at no charge. 409-866-0023

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