For a 6-month project, renting a filter press typically costs 50 to 70% of the purchase price (8 to 12% of price per month), so renting is cheaper only if the press has no use afterwards. Break-even sits at 8 to 12 months; beyond that, or if the unit can be resold or relocated, buying wins.
Yes. A chamber or membrane filter press can dewater oily sludge and drilling mud to 30 to 45% cake moisture when free oil is kept below about 10 to 15% of solids, the slurry is heated to 50 to 70 °C or demulsified, and monofilament or PTFE-coated cloth is used. Cycle times run 1.5 to 4 hours.
A multi-disc screw press dewaters sludge to 15 to 25% dry solids at 8 to 20 kWh/t DS with minimal labour; a chamber or membrane filter press reaches 30 to 50% DS at 15 to 30 kWh/t DS. Below 1 t DS/day the screw press is cheaper to run; above 3 t DS/day the filter press wins on disposal cost.
To calculate the number of filter press plates, convert dry solids per day into wet cake volume (cake density 1.2 to 1.6 t/m³), divide by cycles per day, then divide by the chamber volume of one plate (9 L for 630 mm to 55 L for 1500 mm at 30 mm depth) and apply a 1.2 to 1.3 safety factor.
A chamber filter press dewaters marble, granite and engineered stone cutting slurry from 10 to 30% solids to a 20 to 28% moisture cake in 20 to 40 minute cycles and returns 90 to 95% of the water to the saws. Most cutting shops use 800 to 1250 mm plates, abrasion-resistant monofilament cloth, and automatic plate shifting for unattended operation.
A chamber filter press dewaters textile dyeing wastewater sludge from 2 to 4% solids to a 60 to 70% moisture cake; a membrane press reaches 50 to 55%. A 1,000 m³/day dyeing plant produces 400 to 800 kg of dry solids per day and typically needs one 1000 mm press with 50 to 80 plates.