The varieties of organic waste suitable for anaerobic digestion are numerous. Waterleau has designed technologies to cope with different organic substrates. We can distinguish different types of substrates according to the source.
- The organic fraction of municipal solid waste (OF MSW)
- Kitchen & restaurant waste (KRW)
- Agriculture : manure/dung/litter & energy crops
- Animal and slaughterhouse waste
- Industrial waste from the food industry / expired food waste
- Biosolids such as sludge from wastewater treatment
The composition of organic waste is often heterogeneous and subject to seasonal fluctuations. After the biogas production by anaerobic digestion, the solid part of the digestate can either be dried and turned into a high standard fertilizer or composted into a commercial product, while the liquid fraction can undergo an aerobic treatment and evaporation step to produce clean water and a valuable nutrient concentrate.
Source, amount of contraries and dry matter content have an effect on the energy yield and anaerobic digestion technology train.
From the technology point of view, energy recovery from biomass incineration shows a lot of similarities to energy recovery from waste. The same technologies are used ENERGIZE® grate, TURNOVER® rotary kiln, HELIOSOLIDS® fluidised bed). The appropriate technology depends on the nature (dimension, density, shape) of the biomass. Compared to the incineration of inorganic waste, combustion of biomass usually generates less corrosive compounds in the flue gases. This allows a simplified flue gas cleaning system and also an optimal energy efficiency.
Sludge, the by-product of biological wastewater treatment is also considered as biomass. As sludge usually contains too much water, even after mechanical dewatering, it has to be thermally dried. Waterleau’s HYDROGONE® and PUTTART® drying technologies are used for this purpose. After drying, the sludge has a heating value of approx. 16 MJ/kg similar to brown coal and thus is an interesting fuel.