Two unique components devised and implemented by the joint venture team contributed heavily to maintaining the city’s budget and schedule for the project.
The first — used to help minimize site disruption and keep the plant operational — is the sunken caisson construction method, which was utilized for the new influent lift station. This technique is useful for projects, such as this one, where space is constricted by other structures in proximity. During this process, instead of a large excavation, the circular structure is formed and sinks into the ground under its own dead weight using special construction methods.
The second component is a biological treatment system designed with separate mixing and aeration within a single large basin. Biological treatment is provided by a cyclic aeration system to create the necessary anoxic and aerobic conditions to promote nitrogen reduction. Phosphorus removal is achieved through a combination of biological and chemical means. Before implementation, dynamic modeling was used to simulate the conditions at the plant and predict effluent quality and chemical demands.