Energy crisis caused by the population growth, increasing demand, and the limited availability of fossil fuels has led to wastewater-based heat recovery emerging as an alternative energy source. As wastewater-based resource recovery systems are location-specific, a holistic view of their sustainability requires a comprehensive analysis of the effect of local conditions on these systems. This study evaluated the role of climate and population density on the economic and environmental sustainability of drain water heat recovery systems (DWHRS) and compared it to that of a medium-scale district heating system. The DWHRS installed in a cold location showed about 2–2.6 times higher energy recovery and 4 times higher greenhouse gas emissions than that in a hot place. The economic impact was predominantly influenced by the cost of electricity, while the environmental sustainability was found to decrease with a decrease in the ambient temperature and solar radiation. Lower population density increases economic sustainability and lowers environmental sustainability of the system. The DWHRS is more sustainable than the medium-scale district heating system in low population density regions irrespective of the climatic conditions. However, in cold places with a high population density, the trade-off between the economic and environmental sustainability must be evaluated to decide whether to install a small- or medium-scale system. Therefore, it is essential to perform a detailed location-specific analysis before deciding the optimal type of heat recovery system for the location under consideration. The model can be utilized as an evaluation tool to quantify the sustainability of the DWHRS and help consumers decide the most suitable method of waste heat recovery.

由人口增长，需求增加和化石燃料供应有限引起的能源危机导致基于废水的热回收成为替代能源。由于基于废水的资源回收系统是针对特定地点的，因此要全面了解其可持续性，就需要对当地条件对这些系统的影响进行全面分析。这项研究评估了气候和人口密度在排水热回收系统（DWHRS）的经济和环境可持续性中的作用，并将其与中等规模的区域供热系统进行了比较。与寒冷地区相比，安装在寒冷地区的DWHRS的能量回收率高约2–2.6倍，温室气体排放量高4倍。经济影响主要受到电力成本的影响，同时发现环境可持续性随着环境温度和太阳辐射的降低而降低。较低的人口密度提高了经济可持续性，并降低了系统的环境可持续性。不管气候条件如何，在人口密度低的地区，DWHRS都比中等规模的区域供热系统更具可持续性。但是，在人口密度高的寒冷地区，必须评估经济和环境可持续性之间的权衡，以决定是否安装小型或中型系统。因此，在确定所考虑位置的最佳热回收系统类型之前，必须进行详细的特定位置分析。