Drying takes dewatered cake from around 20 to 30 percent solids to 60 to 95 percent, slashing mass and volume and producing a stable, storable product suitable for reuse or thermal recovery.
Removing residual water cuts haulage and disposal mass several-fold.
Dried sludge is stable, low-odour and storable, decoupling disposal from production.
High dry-solids product can be used as a soil improver or thermally valorised as a fuel.
Evaporating water requires about 2.26 MJ per kg, so drying energy is dominated by the latent heat of the water removed.
Sludge passes through a sticky, glue-like phase around 40 to 60 percent solids that the dryer must manage.
Recovering evaporative and exhaust heat is essential to viable drying energy feasibility.
Because the latent heat of vaporisation is about 2.26 MJ/kg of water, the energy to dry sludge is set almost entirely by the mass of water removed, which is why upstream dewatering to maximum cake solids is the cheapest 'drying' available. A thermal dryer's net energy demand is reduced by recovering heat from the exhaust vapour and, where available, by using waste heat from digester combined heat and power or solar gain, turning drying into part of an integrated energy strategy.
Belt, drum and disc dryers with heat recovery for high-throughput drying.
Low-energy solar drying with automated turning for moderate climates.
Cooling, storage and conveying of the dried product.
Reynolds & Bauhm engineers complete sludge treatment trains — thickening, conditioning, dewatering, stabilisation and drying — matched to your solids and disposal route.
Our expertise spans multiple industries with sector-specific water treatment solutions.