General terms for this industry are: Waste Water Treatment and Bio-Mass, Waste to Energy, Municipal waste, Car Shredders, Land Fill replacement Plants Meat and Bone meal, and these are now becoming the biggest growth in Green field installations, as countries come to terms with their waste problems. Processes handling a combination of Dust, Gas and Vapour hazards are beginning to be developed, requiring the full range of Explosion prevention and protection systems available.
The sludge starts as a wet mix at the start of the Drum Dryer, and as it makes its way to the discharge screw, it becomes dryer and potentially more unstable. The product if thermally unsafe is discharged to a safe bin outside or cooled in a series of cooling screws before being lifted to the Sifter for grading into different sizes. Unusually the screws after the Drum Dryer have been the most dangerous risk, due to thermal instability. Protection is mostly chemical barriers along the screws with venting either to a safe area outside or if that not’s possible, flameless venting inside the building. Good house keeping is important as sludge pellets are a fuel source and dispersion of the dust layers is to be avoided.