Since the age of imprudent disposal of human waste has passed, a cost-effective, environmentally-friendly alternative for the disposal of sewage sludge has been sought-after. The Institute for Environmental Management of the Hochschule Bremen produced a research report concerning the processing of waste prior to burning: The Dehydration of Sludge (German). The conclusion was similar to the results of many previous comparisons between techniques utilizing renewable energy and fossil fuels: investment costs of renewable energy, in this case solar thermal energy, lie above those using natural gas. However, in terms of operating costs, solar thermal energy is indubitably more economically advantageous. In addition, there are other benefits to sewage sludge dehydration utilizing the sun, such as the ability to use waste heat and lack of large amounts of carbon dioxide emissions.