The City of Mount Pleasant, like many cities in Texas, experienced a significant drought in 2011. The water shortage tested the limits of Mount Pleasant’s only water treatment plant, the I-30 facility. In response, the City of Mount Pleasant enlisted KSA to upgrade the water treatment capabilities of the city through a program that consisted of three projects. The first project was a new, secondary water treatment plant named after the city’s primary water resource, Lake Bob Sandlin. The second project involved constructing and modifying raw water pipelines and treated water transmission lines that integrated both the new plant and existing plants. The third project in the program was to make improvements to the I-30 Water Treatment Plant.
The I-30 Water Treatment Plant had been operating for over 30 years and was overdue for long-lasting modifications and repairs. KSA provided surveying services as well as civil, electrical, instrumentation and controls and structural engineering services; in addition to construction administrative services to facilitate the much-need improvements. The plant had two, large clearwells that had to be modified to meet American Water Works Association (AWWA) and Texas Commission on Environmental Quality (TCEQ) requirements. The clearwell repairs included replacing vents and man-ways, mending leaks in the floor, sandblasting and repainting. The schedule 10 welded steel pipe in the filter pipe gallery was in poor condition, prone to leaks and failures. This thin walled steel pipe was replaced with ductile iron pipe and fittings, which is more corrosion-resistant than steel.
Safe and Efficient
The project replaced all of the high service across-the-line starters with variable speed starters. KSA also designed a new electrical building to house the plant’s new variable frequency drives. Before the modifications, the plant was limited to emergency pumping with only one pump designated for high services and one standby engine-driven pump. The project included replacing the standby engine-driven pump with an electrically driven pump. In addition to creating a more environmentally friendly facility, the changes KSA designed made the plant safer; they removed a significant heat source from the high service pump station that, in the past, had adversely impacted the operation of the facility. In addition, a “load shed” was designed for the high service pumps to provide an array of available pumps for emergencies, alleviating the dependence on one dedicated emergency pump. During construction, KSA discovered low pressures on the suction side of the plant’s high-service pumps that were impacting efficient operation and causing damage to the equipment. A second suction supply feed was designed from the clearwells to alleviate the low suction pressure issue. The new variable frequency drives (VFD’s) are more energy-efficient and can be adjusted to pace the pumping rate to match demand.
KSA added highly desired filter-to-waste provisions, which allows filtered water to be bypassed so that the operators do not send water of marginal quality to the clearwell. The project team also resolved multiple control issues for dependable, remote operation of the filter system. The system included two filter backwash pumps, both of which were in poor condition. One backwash pump was replaced with a new unit. The other backwash pump was removed and a new automated control valve system was designed to take water from the high service system. The valve system is significantly less expensive than an additional backwash pump and incorporates controls to read and modulate flow rates, plus it maintains pressure in the distribution system.
The construction of improvements to Mount Pleasant’s primary water source did not interfere with the city’s ability to deliver water to its businesses and residents. To achieve this difficult task, KSA conducted monthly progress meetings with the city, design team, contractors, operators and KSA’s on-site resident project representative to discuss completed work and coordinate plans for future work. The project team stayed connected by phone and email and met more frequently whenever necessary to ensure the smooth and timely completion of the project. KSA’s design team was flexible and competently maximized the effectiveness of the dollars allocated for the project to meet the needs of the City of Mount Pleasant and the operators of the I-30 Water Treatment Plant.
Instrumentation and Controls Engineering
Key KSA Staff
John Ringler, P.E., Principal in Charge
John Ringler, P.E., Project Manager
Jerry Nolan, Resident Project Representative
John Flahie, Resident Project Representative
City of Mount Pleasant
Mike Ahrens, City Manager
City of Mount Pleasant
Anthony Rasor, Director of Utilities
City of Mount Pleasant
11 MGD (Millions of gallons per day)