Most types of waste contain a substantial combustible fraction. e.g. household waste usually contains paper, plastic, biomass, ... which has an important heating value.

But most waste flows also contain inert matter and water which evidently do not have an energy generating potential. As a whole, the mixture of combustible and non-combustible matter that makes up waste, has a heating value of anywhere from 4 to 40 MJ/kg.

The higher the heating value of the waste the more potential it has as source of energy. When the combustible matter mainly is organic in origin, this energy is called renewable or sustainable.

How it works is explained in the section on waste treatment. The energy in the waste is released through oxidation at high temperature (incineration or combustion). The end product of this is a hot flue gas flow. In a boiler the thermal energy of the flue gases is transferred to a heat carrying medium such as steam, hot water, hot thermal oil, ... This heated medium can than be used for heating purposes, for power generation (in the case of steam in a steam turbine) or any other heat application.

Different waste combustion systems exist, based on the nature of the waste (grate, rotary kiln, fluidized bed, gas burner, liquid burner). WATERLEAU has proprietary technology for each of these systems (ENERGIZE®, TURNOVER®, HELIOSOLIDS®, DYNAFLUID®).