Integrating alum sludge with waste-activated sludge in co-conditioning and dewatering: a case study of a city in south France

• Published in: Environmental science and pollution research international Vol. 27; no. 13; pp. 14863 - 14871
• Main Authors: Ren, Baiming, Lyczko, Nathalie, Zhao, Yaqian, Nzihou, Ange
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2020; Springer Nature B.V; Springer Verlag
• Subjects: Activated sludge; Addition polymerization; Alum sludge; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Circular economy; Conditioning; Cost analysis; Dewatering; Earth and Environmental Science; Ecotoxicology; Engineering Sciences; Environment; Environmental Chemistry; Environmental Health; Environmental science; Geographical distribution; Geographical locations; Polymers; Research Article; Sludge; Suction; Waste Water Technology; Wastewater treatment; Wastewater treatment plants; Water Management; Water Pollution Control; Water utilities; Waterworks; France; Alum sludge reuse; Techno-economic analysis; Jar test; Circular economy; Sewerage sludge; Waterworks residues; Circular Economy
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-08056-0

The unique geographical location of waterworks and wastewater treatment plant (WWTP) in Graulhet (France) profited the environmental resource integration and “Circular Economy.” Alum sludge from a local waterworks was introduced to co-conditioning and dewatering with waste-activated sludge from a nearby WWTP to examine the role of the alum sludge in improving the dewaterability of the mixed sludge. Experiments demonstrated that the optimal mixing ratio was 1:1 (waste-activated sludge/alum sludge, v/v). Alum sludge has been shown to beneficially enhance mixed sludge dewaterability, by decreasing both the specific resistance to filtration (SRF) and the capillary suction time (CST). Moreover, the optimal polymer (Sueprfloc-492HMW) dose for the mixed sludge (mix ratio 1:1) was 200 mg/L, highlighting a huge savings (14 times) in polymer addition without alum sludge involvement. In addition, cost-effective analysis of its potential full-scale application has demonstrated that the initial investment could be returned in 11 years. The co-conditioning and dewatering strategy can be viewed as a “win-win” strategy for the Graulhet, France, water and wastewater industry. Graphical abstract