Access Water

By Brian Fuerst, CH2M HILL Senior Project Manager

The growing City of Waco, Texas, is located about 100 miles south of Dallas. Prior to the City of Waco Water Quality and Quantity Improvement Project, the City’s drinking water from Lake Waco was treated at two conventional water treatment plants: the 42-million-gallon/day (mgd) Mt. Carmel Water Treatment Plant (WTP), and the 24-mgd Riverside WTP. The watershed for Lake Waco includes the highest concentration of dairy farms in Texas, resulting in high nutrient loadings and algae growth in the Lake. Periodic algae blooms led to the release of geosmin during the treatment process and gave Waco water a reputation of being nearly undrinkable during certain times of the year.

To remedy its water problems, the City of Waco partnered with CH2M HILL and The Wallace Group to design improvements to the Mt. Carmel and Riverside WTPs, as well as to: expand the total system treatment capacity from 66-mgd to 90-mgd initially and 135-mgd ultimately; eliminate hydraulic bottlenecks in the existing system; improve performance of aging equipment; and, reduce taste and odor episodes in the City’s potable water.

CH2M HILL and The Wallace Group incorporated a number of innovative features to improve performance, reduce costs, and enhance aesthetics. For example, the new 90-mgd clarification facility located near the raw water intake at Lake Waco is the first dissolved air flotation (DAF) plant for water treatment in the State of Texas, as well as one of the first WTPs in the U.S. to use DAF for taste and odor control, as well as clarification. Regulatory approval required five pilot studies and four rounds of bench scale tests to obtain data on DAF and ozone performance. CH2M HILL used decision science techniques to analyze the results and select the best alternatives based on the cost and benefits important to Waco. As a result of these studies, not only was regulatory approval obtained for both the DAF and the ozone processes, but the DAF loading rate was increased from the standard 6 gallons per minute(gpm)/square foot, to 12 gpm/square foot, resulting in about $10 million in construction cost savings.

We were also careful to analyze the social and ecological complexities of the project. Both of the existing water treatment plants are located near residential areas. The new DAF facility also has nearby neighbors, but CH2M HILL and The Wallace Group conducted a series of public meetings to obtain input and designed the new facilities to mitigate the neighbors’ concerns. For example, potential algae odors were mitigated by covering the DAF basins and diverting the odorous air back to the lake to provide aeration that reduces algae growth near the intake. To reduce unappealing visual impacts, many of the DAF plant facilities, including the ozone facilities and balancing basins, were constructed underground and covered with native landscaping and ground coverings. Existing trees and landscape were left in place where possible. As a result, the City was able to get the plant site designated as an official Texas Wildscape by the Texas Parks and Wildlife Department.

Blind taste tests conducted by the local newspaper confirmed the processes effectiveness. The water quality has gone from a source of woe to a source of pride and economic development for the City. In fact, I am pleased to share that the City of Waco Water Quality and Quantity Improvement Project has been selected as a Water and Wastes Digest Magazine Top Projects for 2011 and was a silver medal winner in The Texas Council of Engineering Companies Engineering Excellence Awards competition based on the project’s successes and outstanding achievements.

With more than 25 years of experience, Brian Fuerst has participated in numerous studies, designs, and construction services for a variety of water and wastewater projects. He has extensive experience in process design and project management of water and wastewater facilities, and offers expertise in all phases of services during the planning and construction of water and wastewater projects.