Large amounts of large-scale debris in primary wastewater, such as plastic bags and leaves, cause pollution of equipment and pipelines. The traditional filtering means and mechanical grills can not handle these debris in practice. To the land, clean, debris transport and the surrounding environmental pollution, even with this simplest water treatment process, its processing costs should be much higher than the heat pump from the water to take heat and take the cold value, Moreover, in urban areas The area of ​​water treatment technology is also a problem. This undoubtedly brought an extinctive catastrophe to the city's primary sewage-source heat pump, which is exactly why the technology is delayed in development. Therefore, it is not feasible to deal with the water treatment in the traditional sense for solving the problem of blockage and pollution of the heat exchange equipment and the pipeline by the bad water quality. Due to the characteristics of the water quality of the primary sewage, compared with other water source heat pump technology has its own two characteristics, but also the key technology of the system.