Thermal Dewatering (TDW) to Reduce the Water Content of Sludge

ABSTRACT

Thermal dewatering describes the process whereby a heating plate and heat supply unit are incorporated into a filter press system to improve separation of water from sludge. The performance of our thermal dewatering system for both wastewater and waterworks sludge was measured and compared with mechanical dewatering in terms of water content, dewatering velocity, cake specific resistance, and energy consumption. Dewatering velocity was improved by a factor of two, cake water content was lower, and specific cake resistance was improved. However, energy consumption was higher. Thermal dewatering systems may be economical and have practical application to improving dewaterability.

Keywords:

• Thermal dewatering
• Water content
• Dewatering velocity
• Cake specific resistance
• Energy consumption

ACKNOWLEDGMENTS

This study was carried out as part of research project entitled “The drying and dewatering system development for sludge reduction and reuse” sponsored by the Ministry of Commerce, Industry and Energy (Project No. 10024221).

Notes

^a Waterworks sludge.

^b Wastewater sludge.

MDW: Mechanical dewatering filter press, TDW: Thermal dewatering filter press.

Note. MMD: Mass median diameter.

Note. A = (Gradient · 2 · A² · ΔP)/(μ · c); SCR: Specific cake resistance.

Note. DS: Dry solid.