Manhole riser prevents infiltration and improves public safety
Problem: The St. Louis Water department raised manholes to grade by manually exposing and lifting concrete grade rings, a process that takes several hours and compromises new paving lifts. After jackhammering and raising, the newly raised rims have to be sealed in with new concrete, creating seams in the new pavement that wear faster than undamaged concrete. It was clearly a problem, so it made sense to do a pilot test with an adjustable riser.
Solution: The American Highway Products riser relies on a pivoted turnbuckle that can be expanded with a screwdriver. The screwdriver, used as a lever, exerts thousands of pounds of mechanical force, seating the riser in the original rim solidly and securely. “For the pilot test, we put a riser in an intersection on Kingshighway Boulevard, one of our busiest downtown roads,” says Vince Foggie, St. Louis Water department superintendent. “It was easy to install, stayed put and didn’t cause any problems, and it didn’t rattle. It was very encouraging, especially since we were getting behind on paving at the time.”
Results: The at-grade risers were better for the roads in many ways. They didn’t set low, so water didn’t collect around the manhole lid, causing excessive infiltration. The city was able to save time and money, do more water department work and keep the public safer. 888-272-2397; www.ahp1.com
Crystalline technology accelerates sewer construction
Problem: The Thames Tideway Tunnel, London’s “super sewer,” aims to prevent millions of tons of pollution from entering the River Thames. Its west section initially included a sprayed concrete liner, waterproof membrane and a cast-in-place secondary liner. However, a higher-end waterproofing solution was needed.
Solution: The Hammersmith Dropshaft and Connection Tunnel – constructed by the BAM Nuttall, Morgan Sindall and Balfour Beatty joint venture, incorporated Xypex Admix C-Series into the primary liner shotcrete, eliminating the need for a waterproof membrane, reducing construction activities and trades on site, and providing superior permanent waterproofing and protection. A total of 100,000 kg of Xypex Admix C-Series was used, enabling the secondary liner to be cast directly. Besides waterproofing, Xypex self-heals cracks up to 0.5 mm and resists aggressive chemicals in sewage infrastructure, reducing future maintenance costs and increasing durability.
Result: This streamlined construction and shortened the project schedule by 11 weeks for the dropshaft and seven weeks for the tunnel. “The number of activities has been reduced,” says Edward Batty, tunneling manager. “The number of resources required for the different interfaces have also been reduced.” 800-961-4477; www.xypex.com
Easy installation of insertion valve saves time and money
Problem: The city of Phoenix Water Service Department needed a valve replacement in the vicinity of a hospital, doctors’ offices and a dialysis center — an area which would be problematic if a lengthy shutdown occurred. Typically, replacing a broken valve in such an area would involve turning off the water supply to these key locations affecting a large number of customers.
Solution: Instead, the city installed a 6-inch PermaSeal Insertion Valve from Mueller to reduce nonrevenue water loss and limit customer shutdowns. The area was excavated the day prior to the installation, the main was plated and then the live installation of the valve took place the next day. The advanced design of the valve integrates the functionality and performance of the A-2361 Resilient Wedge Gate Valve and H-600 Series ductile iron tapping sleeve. With its clean-seat technology, the insertion valve provides users with reliable and repeatable watertight shut off, suitable for an exercise program, by having the gate seated on the precision cast surface of the valve body and not the host pipe. With a 350 psi rating, the valve allows for insertion into existing water mains with minimal service disruption and dependable functional service life.
Result: The new valve was successfully installed in approximately three hours and the team was able to flush the waterline and perform a brief shutdown to test that the line was dry, confirming that the installation was successful. The valve significantly reduced service downtime to customers, and the speedy installation saved time and money. 800-423-1323; www.muellerwaterproducts.com
Wastewater system designed to grow with community
Problem: The Valley Knolls housing development was a multi-phased project with single family units, triplex units, a community center and recreational facilities. The project required a new wastewater station to service the new housing development. The problem was that the development was being built in phases and would experience different flow at each phase. The wastewater pumping station starts with approximately 100 gpm pumps and will work up to 900 to 1,000 gpm pumps in later phases.
Solution: From a high level, Romtec Utilities set the wastewater system up to accommodate the “now” budget and demands for the system. Then, as the development continues into later phases, additional pumps and larger pumps will be added to accommodate larger flows. This keeps costs down initially and allows for a better sized system relative to flow. Phase one utilized a duplex 11 hp Flygt submersible pump. The sizing of the pumps keeps the system cheaper at each phase. It prevents the developer who is developing the first phase from having to pay for the full system buildout. A developer may sell off the development after the first few phases and does not want to pay for costs that fall under later development phases.
Result: This project is set up to accommodate both “now” and “future” flows by providing a phased lift station. It keeps costs down at the beginning and properly sizes the system for the current flow. The oversized wet well accommodates now and future flows without the need for another wet well. The round structure helps direct flows to the pump intake. 541-496-3541; www.romtecutilities.com
