THE OPPORTUNITY

Over the past several years, the WTSA has had increasing levels of Infiltration and Inflow (I&I) in their sewer collection systems. These extraneous flows reduce the available capacity in the collections systems and plants, cause maintenance and operational issues and are a detriment to the long term compliance with their NJPDES permits.

THE CHALLENGE

PS&S needed to investigate, find, and reduce average and peak flows to their wastewater treatment plants to ensure long term compliance with their NJPDES permits and provide for consistent and continual capacity in their collection systems.

Implementation of the investigate and remediation was difficult in easements, along streams, and other tough to reach locations. These areas were able to be completed through detailed coordination between the Authority, engineers PS&S and the pipe and manhole rehabilitation Contractors. In addition, due to COVID restrictions/impacts many residents in both SSA’s were home during the day while work was being performed which required a greater level of public relations coordination and outreach.

THE PS&S SOLUTION

The program ultimately achieved the stated goals through the performance of flow studies in several sewer service areas, GIS mapping locating assets, smoke testing and the CCTV’ing of approximately 59,500 linear feet (LF) of sewer lines in the Stage I/II SSA and 87,306 LF of sewer lines in the Stage IV SSA. In addition, the WTSA implemented a new technology Focused Electronic Leak Location (FELL) testing on 9,440 LF of the collection system located in hard-to-reach easement locations. The WTSA also invested in purchasing temporary flow meters for deployment though-out the SSA to monitor wet weather flows and determine sub basins in need of further investigation or rehabilitation work. Once all the data was collected and reviewed to confirm and locate sources of I&I the remediation and removal of the I&I was performed under the following capital improvement projects:

Contract 60 – Stage I/II SSA Collection System Rehabilitation Project: This project entailed the rehabilitation of sewers and manholes in the Stage I/II SSA including approximately 11,500 LF of 8” Cured In Place Pipe (CIPP) Lining, 1,000 LF of 12” CIPP Lining, 16 lateral connection repairs, 161 LF of manhole lining rehabilitation and general sewer collection maintenance work.

Contract 61- Stage IV SSA Collection System Rehabilitation Project: This project entailed the rehabilitation of sewers and manholes in the Stage IV SSA, including approximately 16,100 LF of 8” Cured In Place Pipe (CIPP) Lining, 800 LF of 12” CIPP Lining, 12 lateral connection repairs, 300 LF of manhole lining rehabilitation and general sewer collection maintenance work.

Both projects were to reduce wet weather peak I&I flows to the Stage I/II WWTF and Stage IV WWTF and maintain the long term “health” of the collection systems. In addition, both projects were scoped to be trenchless cured-in-place (CIP) lining projects which caused minimal disruption during construction to residences and no excavation in neighborhoods was required.

The WTSA received the Association of Environmental Authorities (AEA) 2021 Best Management Practices Award for these projects.