Polymer-assisted hydraulic dredging for quality control of stormwater pond sediment and reject water – Influence of polymer choice and its preparation

• Hydraulic dredging of stormwater ponds may include on-site dewatering of dredged materials using polymersand geotextile filtration. The choice of polymer and its preparation affect the overall operational effectivenessand the quality of the reject water (filtrate) returned to the stormwater pond. This study examined the resultingparticle content as well as nutrient and metal concentrations in the filtrate conducted on hydraulically dredgedstormwater sediment that was chemically conditioned and filtered through geotextile. This study investigateshow polymer choice and preparation affects the outcome. In total, three types of polymers were tested (powder,emulsion commercial cationic polymers and chitosan), the water (tap water or reclaimed) the polymer wasprepared in, and the aging time of the polymer solution. Deviations from manufacturer's instructions on thepolymer preparation increased the amount of polymer needed for an optimal conditioning process. In terms ofpollutant retention, there was no difference between polymer preparations. In the filter cake there was nodiscernable difference between conditioned and unconditioned sediment, rather the difference was noticeable onthe filtrate. Conditioned stormwater sediment produced a geotextile filtrate with considerably less metal andnutrient content than the unconditioned stormwater sediment.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Samhällsbyggnadsteknik -- Vattenteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Civil Engineering -- Water Engineering (hsv//eng)

Nyckelord

Stormwater sediment

Stormwater pond

Hydraulic dredging

Polymer-assisted

Polymer preparation

Aging

Reclaimed water

Centrumbildning - Centrum för dagvattenhantering (DRIZZLE)

Centre - Centre for Stormwater Management (DRIZZLE)

VA-teknik

Urban Water Engineering

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)