Sustainable Biogas Production In Municipal Wastewater Treatment Plants
Introduction
Anaerobic digestion (AD) is a proven technology for sewage sludge treatment and allows the generation of renewable energy from the same process. During AD, microorganisms break down the organic matter contained in the sludge and convert it into biogas, a mixture of mainly methane and carbon dioxide, which can be used for electricity, heat, and biofuel production. At the same time, the sludge is stabilized and its dry matter content is reduced. The benefits of AD of sewage sludge are widely recognized and the technology is well established in many countries. Today, a high proportion of biogas produced in AD plants is from those on municipal wastewater treatment sites (see Table 1) and there is still an enormous potential to exploit worldwide. Sewage sludge is produced in wastewater treatment plants (WWTPs) as part of the water-cleaning process. The sludge contains the particles removed from the wastewater, which are rich in nutrients and organic matter, leaving the water clean for its release into nature. Growing population centers and expanding industry, which is increasingly well served by wastewater treatment facilities, resulting in the rapid growth of sewage sludge production. As important consumers and generators of energy, WWTPs are one of the numerous players influencing developments toward energy sustainability. The present brochure aims to encourage sustainable and efficient production, conversion, and utilization of biogas in municipal WWTPs, including the closing of nutrient cycles, whenever this is legally and technically possible. It is addressed to energy policy- and decision makers as well as WWTP operators. It allows an understanding context and interactions involved in the treatment processes, but it is not meant as a technical guideline for project management. Specialists must also be involved in detailed studies and implementation of new treatment concepts and technologies. The three main objectives of the brochure are:
• To acknowledge the importance of AD in WWTPs
• To provide information about benefits and challenges
• To encourage optimization of biogas production and utilization
Sustainable Biogas Production In Municipal Wastewater Treatment Plants
Introduction
Anaerobic digestion (AD) is a proven technology for sewage sludge treatment and allows the generation of renewable energy from the same process. During AD, microorganisms break down the organic matter contained in the sludge and convert it into biogas, a mixture of mainly methane and carbon dioxide, which can be used for electricity, heat, and biofuel production. At the same time, the sludge is stabilized and its dry matter content is reduced. The benefits of AD of sewage sludge are widely recognized and the technology is well established in many countries. Today, a high proportion of biogas produced in AD plants is from those on municipal wastewater treatment sites (see Table 1) and there is still an enormous potential to exploit worldwide. Sewage sludge is produced in wastewater treatment plants (WWTPs) as part of the water-cleaning process. The sludge contains the particles removed from the wastewater, which are rich in nutrients and organic matter, leaving the water clean for its release into nature. Growing population centers and expanding industry, which is increasingly well served by wastewater treatment facilities, resulting in the rapid growth of sewage sludge production. As important consumers and generators of energy, WWTPs are one of the numerous players influencing developments toward energy sustainability. The present brochure aims to encourage sustainable and efficient production, conversion, and utilization of biogas in municipal WWTPs, including the closing of nutrient cycles, whenever this is legally and technically possible. It is addressed to energy policy- and decision makers as well as WWTP operators. It allows an understanding context and interactions involved in the treatment processes, but it is not meant as a technical guideline for project management. Specialists must also be involved in detailed studies and implementation of new treatment concepts and technologies. The three main objectives of the brochure are:
• To acknowledge the importance of AD in WWTPs
• To provide information about benefits and challenges
• To encourage optimization of biogas production and utilization
The Drainge Basins
Introduction
Two general relationships were realized concerning drainage basins
* streams form their valleys in which they flow
* every river consists of a major stream that is fed by a number of mutually adjusted branches that diminish in size away from the main stem
- Slope Hydrology and Runoff Generation A. Basin Hydro. Cycle and Budget Input = Output + change in storage Overland flow Interflow Baseflow
The Drainge Basins
Introduction
Two general relationships were realized concerning drainage basins
* streams form their valleys in which they flow
* every river consists of a major stream that is fed by a number of mutually adjusted branches that diminish in size away from the main stem
- Slope Hydrology and Runoff Generation A. Basin Hydro. Cycle and Budget Input = Output + change in storage Overland flow Interflow Baseflow
