by Shane Henson — September 17, 2012—Honeywell, global manufacturer of technologies to address tough challenges linked to global macrotrends such as safety, security, and energy, has been contracted to oversee a $35-million renewable energy project for the City of Wilmington, Delaware. The project will feature a first-of-its-kind facility that converts two sources of biogas into power and heat for the citys wastewater treatment plant.
The project is part of a city-wide initiative to decrease energy costs and greenhouse gas emissions, a program that has also included Honeywell-led solar installations and energy-efficient building improvements. Combined, the upgrades will help the city trim its carbon footprint by approximately 35% and meet nearly 50% of its electricity needs with renewable energy, says Honeywell.
While this large-scale project does require significant capital, Wilmington has been able to make these energy and environmental-focused improvements without increasing budgets or taxes, city officials say. City officials intend to use the subsequent reduction in utility and operating costs, savings that are guaranteed through performance contracts with Honeywell, to fund the upgrades and ongoing support. In addition, the work is expected to deliver savings beyond the money required to finance the activities.
According to Honeywell, the centerpiece of the new project is the construction of a Renewable Energy Biosolids Facility to harvest and harness naturally occurring biogas, supplying a renewable resource to not only generate electricity for the Hay Road Wastewater Treatment Plant, but provide thermal drying to greatly reduce the volume of sewage sludge the city pays to remove.
The biosolids facility will capture methane produced by anaerobic digesters at the Hay Road plant, a potential energy source that is currently flared off. The gas will mix with additional methane from the nearby Cherry Island Landfill, which is operated by the Delaware Solid Waste Authority. And the blend will be purified at the facility and used to power reciprocating engines that can generate up to 4 megawatts of electricity, enough energy to provide up to 90% of the treatment plants power.
The biosolids, or sewage sludge, that come out of the digesters will also be dehydrated by heat recovered from the engines. This thermal drying process is expected to reduce the amount of sludge the city needs to truck away by approximately 75%–from 140 to 35 tons per day–greatly reducing material-handling costs.
The biosolids facility is also projected to trim greenhouse gas emissions by 15,700 metric tons annually. According to figures from the U.S. Environmental Protection Agency, the decrease is equivalent to removing more than 3,000 cars from the road.
