Sewer Bypass PEng Designed
Aging infrastructure and new development across Canada is creating a high demand of related infrastructure development projects. In some cases this work is planned and in others in may be as a result of failure, in either case many problems will arise in trying to do work around existing residences, buildings, roads and other structures.
In redevelopment of existing lines or in installation of new systems typically the flow through sewer lines cannot simply be diverted; it must be bypassed or in other terms a temporarily isolation pumping system around the pipe being repaired, replaced or added. This is accomplished using diversion pumps capable of pumping trash and/or sewage are deployed.
Typically, a primary and a backup Pump will be are installed upstream of the existing pipe and a temporary pipeline is installed to transfer effluent downstream of the pipe and reintroduced back into the existing an existing manhole / sewer line. To isolate the effluent flow upstream a temporary plug, which is inflatable to the diameter of the line, is installed between the various sections being worked on. If the customer has not calculated the necessary flow, then NCS Fluid Handling Systems design engineers may be required to size the bypass system and provide engineered calculations with the bypass plan. This is all dependant on the number of homes and types of businesses that the line may serve. The bypass may be required to handle sewage at a low flow or in some city cases up to several thousand gallons per minute (gpm).
NCS Fluid Handling Systems engineering department considers several associated factors to select the proper pump size, support equipment, residential factors like noise (where silent run pumps are used) and traffic (which may require road crossing, to allow traffic over the temporary line.) These factors include sewer line pipe size; excavation pipe depth; duration of the work; access issues; and any other specific factors of the project. NCS Fluid Handling Systems may also be required to install well point dewatering system to maintain a dry excavation and soil stabilization during line installation.
The designed flow may vary throughout the day dependant on use, at peak flow this the highest flow on the pipeline throughout the day. Typically, in cities this usually occurs in the early morning when everyone is getting ready for the day and water consumption peaks and potentially again in the afternoon when everyone starts to return home. In some cases, designers look at event centers or arenas in the area that may host special occasions if off peak hours.
The peak flow must be known for a system to properly perform, never use the average flow as the design benchmark. In many cases once a bypass and construction has started it can’t be taken out of service or modified so proper design is critical at the beginning. Nobody wants to deal with or have to report a spill.
Once and a while a bypass system will required to be installed remote areas where there is lots of space for everything however in most cases, bypasses, are installed in densely populated urban areas where limited disruption can occur. This is where NCS Fluid Handling Systems designers most design the system to minimize the footprint of the system and equipment while considering all safety requirements for contractors and the public in proximity. Traffic patterns are always considered during a diversion and while it may be necessary during in-road installations that a road be temporarily closed NCS designers incorporate specially designed and engineered road crossings allowing the temporary bypass pipe to be directed through the crossing and still allowing traffic to travel without restriction. Additionally, items such as “Echo Barrier” curtains for sound attenuation or sound attenuated pumps may be installed.
To ensure proper design, installation and success “Experience Matters”. When it comes to engineered designs, proper installation, 24-hour monitoring, proper pump selection, support equipment and skilled technicians with comprehensive training and knowledge the entire NCS team is there to support project success. Having general knowledge of pumps alone is not enough. Experience in setup, installation and maintenance of this vital construction service is the best overall requirement for this type of projects. As always, our client’s gat a complete project document turn-over package with run sheets and safety data for their bypass completion package.