Reduced Peak Wastewater Flows by 23% Through a Nineyear Gravity Sewer Lining Program

Abstract

The City of Cocoa (city) is located on the eastern side of central Florida just south of Cape Canaveral. The city maintains a service area that contains roughly 1,891 manholes, 85 mi (2,031 segments) of gravity mains, and 53 sewer basins. The city operates the Jerry Sellers Water Reclamation Facility (WRF), which receives the wastewater flow from the collection system. The plant has a design capacity of 4.5 mil gal per day (mgd) and received an average daily flow of 1.86 mgd in 2022 and 1.63 mgd in 2023. Regular sewer collection system maintenance plays a vital role in ensuring the efficient and effective operation of underground systems and reduced treatment costs. Over time, however, manholes and gravity mains can deteriorate due to exposure to harsh environmental conditions, aging, and heavy usage, leading to structural failures and inflow and infiltration (I/I). As a result, it’s critical to maintain and rehabilitate these systems to prevent potential problems, such as groundwater pollution, system overloading, and damage to surrounding infrastructure. This paper presents the findings of the City’s collection system rehabilitation program, which aimed to assess the condition of manholes/gravity mains, identify structural deficiencies, and recommend suitable repair and rehabilitation solutions. Furthermore, it highlights the importance of ongoing maintenance and monitoring of the collection system to prevent future deterioration and ensure the long-term performance of the sewer system. To institute the collection system rehabilitation process the City worked with various stakeholders including management, city council, staff members, and consulting engineers to develop a plan to address the I/I through a rehabilitation program that focused on the structural deficiencies of the collection system. By working as a team the city was able to determine the general scope of the problem and justify the methodology with leadership.