Removal of dissolved organic matter and phthalic acid esters from landfill leachate through a complexation-flocculation process.
Dissolved organic macromolecules (DOM) and micropollutants, such as phthalic acid esters (PAEs), are often enriched in landfill leachate. PAEs were detected in 10 leachate samples from three landfills in Hubei province, central China. In particular, di-(2-ethyhexyl) phthalate (DEHP) concentration was higher than 70microgL(-1) in most samples, and the highest DEHP concentration was in the colloid fraction (1000Da-0.45microm). Use of flocculants may result in flocculation and precipitation of colloids and associated contaminants, such as DEHP. Biodegradation is not effective for long chain PAEs or the landfill leachate, given the low ratio of BOD5/COD (less than 0.2) and deficient phosphorus content. Complexation-flocculation is therefore proposed as an alternative process for removing DOM and PAEs. Jar-test experiments were employed to investigate the mechanism and feasibility of the process. Among tested coagulants (ferric chloride, aluminum sulfate and poly aluminum chloride (PAC)), PAC was the most efficient. Hydrophobic contaminants with log KOC greater than 4 and DOM in wastewater can be removed simultaneously through the complexation-flocculation process.
Zhang
Caixiang
C
MOE Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, People's Republic of China.
Wang
Yanxin
Y
D005427:Flocculation; D010795:Phthalic Acids / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
D010795:Phthalic Acids; D014874:Water Pollutants, Chemical; D014867:Water