| Abstract [eng] |
Wastewater is one of the most potential heat recovery sources. The domestic, municipal, industrial, etc. wastewater are selected for heat recovery in the most cases. The wastewater of Kaunas wastewater treatment plant has been used in this case of study. The wastewater from the sludge household has been decided to use for the heat recovery. The temperature of it is between 24–28 °C and depends on a seasonal prevalence. The treated wastewater which is released to Nemunas has been used as another heat source for heat recovery. The annual average temperature of this stream is 14 °C. These streams of wastewater are a potential sources of recovered heat energy. The existing amount of heat inside of it has been recovered by double-pipe heat exchanger and heat pump. According to calculations has been recovered 116233 GJ of heat from the annual stream of wastewater. Implementation of heat recovery technologies in the wastewater treatment plant is an important approach not only to energy but to environmental approach as well because the emissions of greenhouse gases decrease. The reduction of carbon dioxide, nitrogen oxides, and carbon monoxide emissions are noticeable in the atmosphere. In the large combustion plants when the natural gas is used to generate the same amount of energy (116233 GJ) the annual emission of carbon dioxide is 6614 t, nitrogen oxides – 3.47 t and carbon monoxide – 0.03 t. The emissions of pollutants approve that the technology which has been chosen does not only reduce the greenhouse gas emission. It is also a successful foundation for sustainable energy development. Energy consumption or part of it can be compensated by formed hydrothermal energy of wastewater. |
