Cloth media filters treat combined sewer overflow

Problem: 

The city of Rushville, Indiana, had to comply with a 2007 consent order for combined sewer overflows polluting the Flatrock River. The city planned to install a 1 million-gallon stormwater storage tank.

Solution: 

The city was approached by Aqua-Aerobic Systems with a pilot test proposal using the AquaStorm cloth media filter. The pilot study captured events from May to July 2015. The results prompted the city to request a design for an AquaStorm filtration system that could treat both dry- and wet-weather flows. An alum coagulant was to be injected upstream of the filters to meet future effluent phosphorus limits and eliminate fine CSO particles.

Result: 

Two 14-disk AquaStorm systems started up in July 2017 with a design average flow of 1 mgd (dry) and 12.6 mgd (peak wet weather). The filters were retrofitted to abandoned sand media filter structures, saving capital costs. The system cost $1 million less than the storage tank proposal. This was the nation’s first AquaStorm filter installation for dual tertiary/wet-weather treatment, and it will keep some 50 million gallons of raw sewage per year from entering the Flatrock River. “With the addition of the AquaStorm filter system and new UV disinfection system, Rushville is discharging the best quality of water to our receiving stream, Flatrock River, than in years past,” says Les Day, utilities director. 815-654-2501; www.aqua-aerobic.com.

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Liner used to end I&I issues in precast manholes

Problem: 

Along one length of the Carroll County (Maryland) Bureau of Utilities’ sanitary sewer force mains, there are nine precast manholes. As with most aging municipal infrastructure, they required regular attention and rehabilitation in order to eliminate inflow and infiltration through their leaking joints.

Solution: 

Pleasants Construction recommended Epoxytec’s CPP Sprayliner. This 100% solids, high-build epoxy paste is blended with fiber-reinforced polymers, providing high strength with flexural properties. The product was applied using an Epoxytec CPP Sprayliner rig. Materials flow through separate (part A and part B), continuously heated hoses. The system has a fixed ratio of 1-to-1 by volume. This structural product was sprayed to achieve a thickness of 100 mils.

Result: 

Applied by a four-man crew, the entire application to all nine manholes took five days. “When searching for manhole solutions, it’s important to find a product with hydrogen sulfide resistance and sealed I&I barrier protection,” says Ron Callahan, director of construction for Pleasants Construction. “CPP Sprayliner offers that protection in an easy-to-apply method.” The successful application and completion of this project will eliminate I&I from these manholes, thus eliminating the costly routine maintenance that was previously required. 877-463-7699; www.epoxytec.com.

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Sealing products stop manhole leaks in minutes

Problem: 

During a newly developed inspections program in the town of Ithaca, New York, infiltration was found throughout the system’s manholes. Joseph Slater, Water & Sewer maintenance supervisor for the town’s Public Works Department, needed to find an economical solution for active leaks that could be handled entirely with in-house personnel.

Solution: 

PARSON SEAL-TITE and PARSON QUICK PLUG, both part of the manhole rehabilitation product line from Parson Environmental Products, were chosen because of their ability to stop active leaks in minutes. PARSON SEAL-TITE is a moisture-insensitive, two-component, fast-reacting hydrophobic polyurethane grout designed to stop high-volume active leaks up to 50 gpm. It is injected at or near the source of the leak, using a manual dual-component caulk gun. The product cures to a dense, rigid mass in approximately 30 seconds and contains no solvents, CFCs or HFCs. PARSON QUICK PLUG is a hydraulic cement material that is mixed with clean, potable water to produce an extremely rapid setting plug. It is inserted into prepared areas to stop active leaks under low to moderate pressure and is suitable for sealing around pipes and conduits.

Result: 

The products were able to quickly and effectively stop the active leaks, even in the most difficult areas on the bottom side of the pipe at the invert. 800-356-9023; www.parsonenvironmental.com.

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Monitoring system enables utility to optimize sewer cleaning

Problem: 

San Antonio Water System was struggling to sustain the demands of monthly cleaning for nearly 200 sites to prevent sanitary sewer overflows in response to an Environmental Protection Agency consent decree. The collections system has about 110,000 manholes and pipeline segments.

Solution: 

SAWS deployed SmartCover Systems at high- frequency cleaning sites over 70 miles of sewer line and performed cleaning only as needed. SmartCover Systems combines real-time monitoring, data transmission via satellite communications, software and analytics to guide sewer operators to exactly where and when to clean.

Result: 

SAWS now monitors level trend changes, and SmartCover Systems provides automated messages for anomalies, allowing the utility to clean only when necessary instead of just in case. The combination of real-time monitoring and trend analysis provides powerful, predictive insights into the behavior of the collections system, enabling visibility of potential problems days or weeks ahead and concurrently providing continuous overflow protection while dispatching cleaning crews only as needed. 760-291-1980; www.smartcoversystems.com.