In order to cope with the tremendous volumes of sludge generated by the effluent treatment plants, and the cost of sludge disposal, the requirement for further sludge volume reduction after mechanical dewatering systems (centrifuges, belt filter presses, chamber filter presses, screw presses….) becomes a necessary step.
As a sludge treatment specialist EMO has developed a range of low temperature dryer.
Among the 3 different technologies of dryers (direct, indirect and mixed) EMO has selected the direct dryer. The EMO belt dryer is designed to be simple, energy efficient and dust free to achieve dryness up to 80-90%.
ADVANTAGES
- Environmental friendly
fully enclosed, no odor emission, no need of expensive and huge gas treatment system - Low temperature, no dust, no explosion hazard
- Economical operational costs
reduced by 2 to 3 times compared with traditional high temperature dryer 15 kW/ Ton of water evaporated. Even further energy reduction by using waste heat : (3kW/ T) - Energy efficient enclosed system
allowing heat recovery, possibility to use recycled energy
OPERATING PRINCIPLE
The sludge coming from the upstream dewatering machines is spread evenly over the first upper of the three level of perforated belts moving at low speed. When moving through this drying tunnel, the sludge is exposed to hot wind moving upwards.
This hot air carries the humidity from the sludge and leads it to a condensing system.
The same air is re-cycled and re-heated thanks to the compressor and is reinjected in the drying tunnel. The dried sludge is discharged from the lower belt into a conveying system. The retention time inside the dryer and therefore drying performances can be adjusted.
Depending on the sludge characteristics, it might go through an extruder that will change the pasty sludge into “spaghetti”. In case the inlet sludge does not reach the 20 % minimum required, a pre-mix system consisting of mixing dewatered sludge with a part of dried sludge might be installed as well.
RANGE
The range of EMO dryers is split into two categories : the Heat Pump (electrical) range and the Waste Heat recovery range. When the waste water treatment plant is equipped with digestor it is possible to recycle the energy in order to enhance the efficiency of the dryer.
