ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Optimisation of sewage sludge dewaterability using BASF CF 802: SRF assessment and implications for anaerobic digestion and thermal treatment

Nassira Kermia, Nawel Elhanafi, Nadjib Drouiche, and Hakim Lounici

Laboratory of Sustainable Materials Development (MDD), Akli Mohand Oulhadj University, Bouira, Algeria

E-mail: drouichenadjib@crtse.dz

Received: 5 April 2026  Accepted: 10 May 2026

Abstract:

High moisture content in municipal sewage sludge remains a major constraint for transportation, handling, and downstream treatment processes such as anaerobic digestion and thermal valorisation. Improving sludge dewaterability prior to further treatment is therefore essential for enhancing operational efficiency. This study evaluates the conditioning of thickened sludge from the Baraki wastewater treatment plant (Algiers, Algeria) using BASF CF 802 polymeric flocculant, with dewaterability assessed through Specific Resistance to Filtration (SRF), dryness, and filtration performance. Polymer conditioning significantly improved sludge dewatering characteristics over the investigated dosage range (0–1.5 g L⁻¹). The optimal dosage was identified at 0.9 g L⁻¹, where dryness increased from 18.0 to 27.6% and SRF decreased from 100 to 24 × 10¹² m kg⁻¹. Filtration rate increased from 0.67 to 2.78 mL s⁻¹, indicating improved cake permeability and enhanced water release. Beyond the optimum dosage, slight deterioration suggested overdosing effects. The increase in dryness resulted in an estimated sludge volume reduction of approximately 34.8%, which may reduce transport requirements and improve operational flexibility. Higher solids concentration may provide advantages for anaerobic digestion through reduced hydraulic loading, although rheological effects should be considered at full scale. Reduced moisture content also improves the feasibility of thermal treatment by lowering evaporation energy demand, although supplementary drying or auxiliary fuel may still be required depending on operating conditions. Overall, BASF CF 802 conditioning provides an effective approach for improving sludge dewaterability and supporting integrated sludge management strategies in large-scale wastewater treatment plants.

Keywords: Sludge dewatering; SRF; Polymer conditioning; Anaerobic digestion; Thermal treatment

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-05042-7

Chemical Papers 80 (9) 10757–10770 (2026)