Treatment of road runoff by coagulation/flocculation and sedimentation

• Published in: Water science and technology Vol. 79; no. 3; pp. 518 - 525
• Main Authors: Nyström, F, Nordqvist, K, Herrmann, I, Hedström, A, Viklander, M
• Format: Journal Article
• Language: English
• Published: England IWA Publishing 01.02.2019
• Subjects: advanced stormwater treatment; Alkalinity; Centre - Centre for Stormwater Management (DRIZZLE); Centrumbildning - Centrum för dagvattenhantering (DRIZZLE); Chromium; Coagulants; Coagulation; Committees; Construction costs; Copper; Environmental engineering; Environmental Monitoring; Experiments; Flocculation; Heavy metals; International organizations; Metals; Particle size; particles; Phosphorus; Pollutants; Quality standards; Rain; Reduction; Reduction (metal working); Retention; road runoff; Roads & highways; Runoff; Scientific imaging; Sedimentation; Sedimentation & deposition; Sewer systems; Soil contamination; Solid suspensions; Standardization; Stormwater; Stormwater management; Surface runoff; Suspended particulate matter; Suspended solids; Turbidity; Urban Water Engineering; VA-teknik; Waste Disposal, Fluid - methods; Water Movements; Water Pollutants, Chemical - chemistry; Water quality; United States > US; Switzerland; Lake Tahoe
• ISSN: 0273-1223; 1996-9732; 1996-9732
• DOI: 10.2166/wst.2019.079

A laboratory investigation of the treatment potential of a coagulation process in the context of stormwater treatment was undertaken. The initial 25 L road runoff generated from four rain events was collected and subjected to a jar-testing regime with two commercial coagulants. The treatment effect was assessed by analysing the runoff before and after treatment for turbidity, suspended solids and metal content. The coagulation process resulted in particle and total metal reduction of more than 90% compared to 40% for only sedimentation. Up to 40% reduction of dissolved Cr, Cu and Pb was also observed compared to 0% for sedimentation. This study shows that coagulation may be a useful process for stormwater treatment systems when the treatment requirements are high.