Thermal treatment – a promising trend in wastewater sludge utilization

Summary

The presence of toxic elements in wastewater sludge generated at the wastewater treatment facilities precludes from using to the full extent the biosludge rich in nitrogen, phosphorus and potassium as efficient organic or combined organomineral fertilizers and potting soil for reclamation of disturbed lands. In this context the task of developing advanced technologies of wastewater sludge treatment in order to mitigate the negative impact on the environment with the use of different passivation methods of active forms of toxic metals has been set. The information on metal furnaces made of hi-tech alloy with fluidized bed for thermal treatment of wastewater sludge is presented in comparison with furnaces made of chamotte brick. Compact modular furnaces have been designed for incinerating 2000–6000 tons of sludge annually at small-scale wastewater treatment facilities. Furnaces for medium and large-scale wastewater treatment facilities have been designed for incinerating from 6000 to 80000 tons of sludge annually. The use of mineral additives and different inorganic sorbents ensures efficient treatment of waste gases. It is shown that metal furnaces with patented design have advantages compared to the traditional furnaces made of chamotte brick particularly when used at small-scale wastewater biological treatment facilities.

Key words

treatment facilities , ecological safety , wastewater sludges , metal furnace with fluidized bed , biosludge incineration