The management of waste water had become a real issue for the EU in the last years. Specialists have been trying to conceive a way to address all the processes and to optimise it. For the waste water the concept is known as Waste Water Management featuring high originality and brings new ways to build, maintain, supervise and repair the sewage. Also, it is a fact that the water temperature in the sewage is varying from 8 to 18 degrees. The solution for using this heat is to put on the sewage pipes heat exchangers able to recover a certain amount of heat. Therm Liner is easy to apply and less costing comparing with other methods. Our challenge was to reduce the heating costs for an apartment building cluster in Pitesti. Because the cluster is heated by a few fairly new heating plants, our idea was to supply the heating plants with warm water. Warming the water will be done using a mix of technologies leading to a significant cost reduction and a world première.