Sewer System Rehabilitation and Retrofit Design
As is the case with any man-made structure, given enough time, pipes, manholes, risers, catch basins, and wells tend to degrade and develop defects due to natural geotechnical, chemical and unnatural (man-made) causes. The severity of a certain defected buried structure and its impact on the level of service, hydraulic capacity or efficiency is specific to the structure's location, intended function and consequence of failure. WRMA's sewer rehabilitation specialists provide inspections and assessments according to standardized condition assessment criteria. WRMA engineers and inspectors are certified by the National Association of Sewer Service Companies (NASSCO), which is the industry recognized national authority on condition assessment criteria for stormwater and sanitary sewer systems. WRMA's engineering team can quickly inspect and assess an existing sewer system for defects and developing degradation and make recommendations, based on the consequence of failure, for an appropriate rehabilitation, repair or replacement procedure.
Sewer System Configuration Versus Rehabilitation Method Selection
While often defected sewer structures must be replaced in their entirety, occasionally, performing a rehabilitation or retrofit can be a more viable and cost efficient alternative. WRMA engineers are experienced in performing evaluations of numerous rehabilitation methods for defected sewer systems. Trenchless methods are often preferred for sewer systems under busy paved roadways while open cut might be possible in less populated and undeveloped areas, however the type of rehabilitation or retrofit chosen will mostly depend on the frequency and severity of defects found during the inspection process as well as the type (wastewater vs. stormwater) and configuration (combined vs. separate) of the sewer system. For example, Combined Sewer systems which combine both stormwater and wastewater flows into a single pipe system are often found in older downtown metropolitan areas, while separate sanitary (wastewater only) sewer systems are found in newer suburban areas. Rehabilitation methods of degraded sewer pipes may include less costly trenchless alternatives such as Pipe Bursting and Cured-In-Place-Pipe (CIPP) lining as opposed to the more costly renewal methods such as Open Cut (excavation) replacement of the entire pipe. WRMA's experienced engineering team can select and design the rehabilitation or replacement of entire sewer systems for a given service area and can prepare task orders and bid packages including plan and profile drawings, CIPP liner thickness calculations, specifications, details, and opinion of probable costs for construction.
Asset Management & Permitting for Wastewaster and MS4 Systems
Keeping a sewer system O&M budget under control is hard enough with the multitudes of planned and unplanned concurrent cleaning and inspection projects throughout your service area. Learn how WRMA's asset management services can help reign in annual O&M costs and deflate ballooning budgets through inventory development and analytics. WRMA is also experienced in permitting for Municipal Separate Storm Sewer Systems (MS4) and has assisted municpal entities in determining which TMDL requirements apply and the steps to be taken to be in compliance with the terms and conditions of an MS4 permit.
WRMA engineers and inspectors are certified by the National Association of Sewer Service Companies (NASSCO) in:
- PACP (Pipeline Assessment Certification Program)
- MACP (Manhole Assessment Certification Program)
- LACP (Lateral Assessment Certification Program)
Sewer Systems For Proposed Developments
WRMA's engineering team is experienced in the design of both stormwater and sanitary sewer systems for new municipal and private development projects. For stormwater sewer systems WRMA can design proposed systems which implement green infrastructure elements to qualify for stormwater credits. For sanitary sewer systems, our engineering team is experienced in the design of gravity systems for government, transportation, residential and commercial facilities. Our civil design team can assist your development team throughout the lifecycle of your project, from the conceptual/planning phase, to permitting, site layout and design. During the planning phase, WRMA's in-house hydrologic and hydraulic modeling capabilities can quickly identify required capacity needs and site all pipe, inlet and manhole structures according to provided easements, right of ways or architectural site layouts. WRMA can also work with local public works departments to ensure proposed sewer systems can be permitted for construction and that adequate mainline service is available. Prior to construction, WRMA can provide bid packages including plan and profile drawings, specifications, details, and opinion of probable costs for construction.