Keep Getting Greener and Cleaner

The Northeast Ohio Regional Sewer District (District) has always been a conscientious steward of the environment and its rate payers. The Northeast Ohio Regional Sewer District was formed by court order in July of 1972 and has been updating and upgrading the biosolids incineration facilities at its Southerly WWTP on an ongoing basis. This paper illustrates the magnitude of improvements as the change from multiple hearth incinerators to the newer technology fluid bed incinerators was made.In July 1972 the District took over the four multiple hearth incinerators built in 1964 at the Southerly WWTP, located in the Village of Cuyahoga Heights, Cuyahoga County, Ohio. Southerly processes solids from two treatment plants, the Southerly WWTP (470,000 cubic meters per day (m3/d) average) and the Easterly WWTP (340,000 m3/d average). The average amount of biosolids processed from the two plants amounts to over 3,175 dry metric tons (Mg) (3,500 dry tons) of biosolids per month.In 2009 the District started constructing the fluid bed incinerator facility to replace the old multiple hearth incinerators. The facility was named the “Renewable Energy Facility” since it also included waste heat boilers to produce steam from the excess heat, which was then used to produce electricity. In addition to the utilizing the resource of wasted heat, the facility installed better emission control equipment. A summary comparison of emissions from the multiple hearth incinerator installation compared to the fluid bed incinerator installation shows a reduction in emissions ranging from 80% to 99% with sulfur dioxides being the exception with only about a 25% reduction.The paper provides a brief history of the District’s continuing efforts to provide a cleaner and greener biosolids handling process as well as documenting operational savings from lower natural gas usage, electricity production and even a gold LEED certification of the administrative portion of the fluid bed incinerator facility. As the name “Renewable Energy Facility” implies, the District included in the design the ability to use scum from its three WWTPs as a renewable fuel source to produce more heat in the fluid bed incinerators, which in turn produced more steam to produce more electricity. The amount of electricity currently being produced is 1.25 megawatts of power with a capacity of about 3 megawatts (MW) during peak solids processing.