High-rate stormwater clarification with polymeric flocculant addition.
Water Sci Technol
; 51(2): 79-88, 2005.
Article
in En
| MEDLINE
| ID: mdl-15790231
ABSTRACT
Treatment of urban stormwater by clarification, with flocculant addition, was studied in Toronto, Canada using a pilot-scale clarifier with removable lamellar plates. Almost 90 stormwater runoff events were characterised at the study site and found fairly polluted. The previous research phase indicated good treatability of this stormwater by lamellar clarification with flocculant addition (total suspended solids, TSS, removal of 84%, at a surface load of 15 m/h), but there were concerns about cleaning plates after storm events. With the aid of numerical modelling, hydraulic improvements to the clarifier inlet zone were retrofitted in 2004 and permitted the removal of the lamellar pack without a loss in treatment efficiency. In the modified clarifier, a cationic polymeric flocculant dosage of 4 mg/L with conventional clarification provided a TSS removal of 77%, at surface loads up to 43 m/h. The use of the polymer did not increase the acute toxicity of the treated effluent. The clarifier sludge was severely polluted by several heavy metals and would require special disposal. The treatment process tested could be well applied in projects requiring intensive stormwater treatment at compact sites.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Waste Disposal, Fluid
/
Oncorhynchus mykiss
/
Water Purification
Type of study:
Prognostic_studies
Limits:
Animals
Country/Region as subject:
America do norte
Language:
En
Journal:
Water Sci Technol
Journal subject:
SAUDE AMBIENTAL
/
TOXICOLOGIA
Year:
2005
Document type:
Article