Metal removal by bed filter materials used in domestic wastewater treatment

• Bed filters using reactive materials are an emerging technology for on-site wastewater treatment. Used materials, which are enriched with phosphorus, can be used as a fertiliser or soil amendment. However the materials can also be enriched with metals from the wastewater. Six materials (opoka, sand, Polonite (R), limestone, two types of blast furnace slag) exposed to long-term wastewater loading in columns and in a compact filter well filled with Polonite were investigated for metal removal and accumulation. Wastewater applied to the columns had low heavy metal concentrations in the order Zn > Cu > Mn > Ni > Cr. All columns were able to remove 53%-83% of Zn except those filled with sand. Polonite demonstrated a high removal capacity of Mn (>98%), while only the slag materials were able to remove Ni. All materials showed increased Cu, Cr(III). Mn. Pb and Zn content after filtration. Speciation calculations showed that high concentrations of dissolved organic matter might have prevented efficient metal removal, particularly in the case of Cu. The low content of toxic heavy metals in the studied filter materials studied would probably not restrict their use as a fertiliser or soil amendment.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Naturresursteknik -- Annan naturresursteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Environmental Engineering -- Other Environmental Engineering (hsv//eng)

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Oceanografi, hydrologi och vattenresurser (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Oceanography, Hydrology and Water Resources (hsv//eng)

Nyckelord

Column experiment

Contamination

Blast furnace slag

Soil amendment

Polonite (R)

blast-furnace slag

phosphorus retention

heavy-metals

sorption

ions

zinc

fertilizer

sorbents

wetlands

calcite

Environmental engineering

Miljöteknik

TECHNOLOGY

Hydrology

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