NEORSD Experiences the Power of Renewable Energy

Abstract

The Northeast Ohio Regional Sewer District (NEORSD) is starting to replace four multiple hearth incinerators (MHIs) at its Southerly Wastewater Treatment Center (WWTC), located in Cuyahoga Heights, Ohio (Cleveland Metropolitan Area) with three new fluidized bed incinerators (FBIs). The plan is to replace the 46 year old MHIs with 3-100 dtpd capacity FBIs. Design work for this project, which started in 2006,did not include power generation with energy recovered from the incinerators. In August of 2008, NEORSD leadership determined that the facility should include energy recovery to produce green electrical power form the biosolids processed, at the recommendation of an independent Validation Panel. This directive was issued to fulfill the NEORSD's mission of protecting the environment and providing cost effective wastewater treatment for their stakeholders.The Validation Panel consisted seven independent biosolids management expert that assessed the NEORSD's proposed long-term biosolids handling program for Southerly, including a fresh look at the incineration project as well as other options. The project was already in preliminary design for the shutdown of the plant's thermal conditioning system and construction of new dewatering and incineration processes. The panel confirmed the NEORSD's plan for biosolids handling, and recommended the integration of the green power facilities into the overall design.With this change, the Southerly Renewable Energy Project was modified to include waste heat boilers (WHBs) to produce steam that would be used to produce electricity using a steam turbine generator. This modified work included auxiliary facilities including water treatment, condensate handling, and controls. This paper summarizes the challenges, benefits, and "lessons learned" in implementing the green power features of the Southerly Renewable Energy Project.

Employing Energy Management Planning to Achieve Net Zero Energy in Wastewater Operations

“…James Welp described the "green energy" component to a sludge incinerator at the Southerly WTP serving Cleveland: "The concept was to capture the energy in the flue gas through a waste heat boiler and use the steam to produce electricity in a steam turbine." (Welp, Mault et al 2010) Further, "The NEORSD decided that the benefits of reduced reliance on purchased power and the environmental benefits outweighed the relatively long payback of 11 years using an electricity cost of $0.07/kWh for the first year of service and escalated power cost factors for subsequent years. " In the NEORSD evaluation, the net energy production from its "green power" system, consisting of condensing steam turbines using waste heat from the biosolids incinerators, provided over 250 kWh/MG of electrical energy..…”