CET Partnership Call 1 / Heat Energy RecOvery from WASTEwater: HERO-WASTE

Short summary The main purpose of this project is to determine the heat energy recovery potential of wastewater at different points of a municipal wastewater treatment plant (WWTP) with a pilot-scale heat energy recovery system that involves a heat pump and a heat exchanger, and to propound the optimum point for heat energy recovery as well as evaluating possible usage area of the recovered heat energy within the WWTP.

Full description Space heating, cooling, and domestic hot water supply account for the majority of energy used in buildings. Hot water in buildings is used for a variety of purposes including showers, sinks, dishwashers, washing machines, and more. On the other hand, wastewater, dissipated from these, retains a significant portion of its initial energy, which can be recovered. By recovering waste heat, the use of fossil fuels in order to heat domestic hot water can be reduced, thereby reducing greenhouse gas emissions into the atmosphere. According to the World Green Building Council, around 28% of global carbon dioxide (CO2) emissions come from building operations, due to the energy used for heating and cooling. Moreover, the European Council published “The 2030 Climate and Energy Framework”, aiming at reducing greenhouse gas emissions by 40% by 2030, and by 80-95% by 2050, relative to the 1990 levels. A renewable energy share target of at least 27% was defined as well. China, the world's biggest emitter of CO2, is aiming to be carbon neutral before 2060 and achieve 60–65% carbon intensity reductions by 2030. Similarly, Europe's ambition is to become the world's first net-zero emissions continent by 2050, compared to1990 levels. Besides, in the United States (US) a target of net-zero emissions by 2050 was announced based on Paris Agreement. In this project, energy recovery potential from wastewater at different points of a WWTP in Istanbul will be examined. To reveal the current energy recovery potential of wastewater with a heat pump system, the pilot scale heat energy recovery system, that consists heat pump and heat exchanger, will be located at different points in WWTP. The heat energy recovery potential of municipal wastewater per m3 wastewater treated will be determined for each point. Besides, in the project, possible usage areas of the recovered energy will also be investigated within WWTP. The heat energy recovered from wastewater has a great potential for energy-neutral or positive WWTPs. There is a significant amount of energy consumption in WWTPs: Energy consumption for advanced biological WWTPs in Istanbul ranged between 19 and 31 kWh/PE.year. Anaerobic digester (AD) is one of the treatment units with the highest energy consumption in WWTPs. Generally, the ADs are operated at either mesophilic (35 °C) or thermophilic (55 °C); therefore, high heat energy is needed to keep it constant at the desired temperature. In addition, heat energy is also needed for sludge drying units and air conditioning at WWTPs. To provide a better understanding of environmental impacts and the economic performance of each point, a Life Cycle Assessment (LCA) and a comprehensive economic evaluation will be conducted. Conventional heating and cooling systems are not suitable for reaching net-zero emission target since they have high CO2 emissions. Thus, the use of technologies, that has low carbon footprint for heating and cooling in residential, commercial, and industrial settings in the world, is needed. Heat pumps, one of the most important environmentally friendly technologies, have been used for a long time in developed countries due to their high energy efficiency. Heat energy recovery systems including a heat pump and heat exchanger can radically reduce the carbon footprint of buildings compared to fossil fueled boiler systems. In wastewater heat pump system, heat exchanger systems are used to provide the energy required for both heating and cooling. However, wastewater may contain various solid particles. For these systems, specific heat exchangers that do not fall under conventional classifications of the heat exchangers should be designed and used. On the other hand, wastewater was officially recognized by the European Union as a renewable source of energy, with the EU Directive 2018/2001.

Advantages and innovations Converting wastewater into a valuable resource with heat energy recovery technology has become increasingly popular due to the advantages of relatively higher energy utilization efficiency and environmental protection. Using a heat energy recovery system for municipal wastewater has lots of advantages including a higher energy efficiency when compared to other heaters (electric boiler, gas boiler, oil and coal boiler), a higher coefficient of performance than the other source heat pumps (air and ground source heat pump), high potential due to high flowrates and an environmental-friendly technology that emits no air pollutants. Moreover, municipal wastewater can be considered as a reliable energy source for heat energy recovery system as the temperature of wastewater is stable throughout the year. There are various applications of heat energy recovery systems from wastewater at different scales in the world. Heat energy is recovered from wastewater by heat energy recovery technology with a capacity of 18.4 MW in Oslo (Norway), and it has a significant contribution to the air conditioning of more than 9000 buildings and provides an annual fuel saving of 6000 tons. WWTPs in Austria contribute 40% of the installed heat power in district heating grids. Besides, in Finland in the Turku region, a new facility, including two 21 MW heat pumps to recover heat energy from wastewater, was built. The facility produces 302 GWh of heat annually, which corresponds to 8% of its district heating. The heat has mainly replaced burning oil and coal, which is estimated to have replaced 5.7 TWh of fossil heat production and reduced emissions by 1.7 MtCO2.

Technical Specification or Expertise Sought Istanbul Technical University (ITU) 2. Istanbul Water and Sewerage Administration (ISKI) 3. Potential Partner-1 4. Potential Partner-2 In HERO-WASTE Project, ITU will take part in the scientific research part, and will be responsible to conduct research studies and evaluate the results of the study. ISKI will provide support to the project in terms of providing the required space for research activities at the selected WWTP. A pilot-scale heat energy recovery system that involves a heat pump and heat exchanger, will be established by the Potential Partner-1 to be located at different points in WWTP. A mathematical modeling study will be carried out by Potential Partner-2 for a full-scale heat energy recovery system using experimental data obtained from the pilot scale system. With this collaboration, a sustainable solution for the problems concerning energy demand and carbon footprint with the implementation of a heat energy recovery system will be proposed. During and/or after the completion of the project, project results will be shared with academia and industry. Publications related to heat recovery from wastewater are expected. The expected role from the Potential Partner-1 The potential partner will be responsible to install and turnkey a pilot-scale heat energy recovery system that involves a heat pump and heat exchanger for different points of the WWTP. The system to be installed should be suitable for different flowrates and temperatures of wastewater since the wastewater flow and temperature would be different at different locations in WWTP. The expected role from the Potential Partner-2 Potential Partner-2 will be responsible for developing a mathematical model for a full-scale heat energy recovery system.

Contact / source: NEXT EEN Widgets (europa.eu)