Treatment of landfill leachate by constructed wetlands: three case studies

Ewa Wojciechowska; Magdalena Gajewska; Hanna Obarska-Pempkowiak

Treatment of landfill leachate by constructed wetlands: three case studies

Abstract

The performance of three CW systems treating landfill leachate, two located in northern Poland (Szadółki near Gdańsk and Gatka near Miastko) and one in southern Sweden (Örebro), is discussed. The CWs differ in size, hydraulic regime, type of hydrophytic plants and type of leachate pre-treatment before discharging to the CW. The CW in Szadółki consists of two parallel beds with sub-surface, horizontal flow of leachate (HSSF) planted with reed. The leachate is discharged to the CW without pre-treatment. The facility in Gatka is a willow plantation, receiving leachate after preliminary sedimentation in a retention pond. The system at Örebro consists of a series of ponds with a surface flow of leachate (the free water surface - FWS wetland), preceded by pre-treatment in an aerated tank with nitrogen stripping. A comparison of treatment conditions and results is presented. The best treatment efficiencies were observed at the CW Örebro (98% TSS, 91% BOD, 65% COD,99.5% N-NH4+), which resulted from (i) an effective pre-treatment of leachate before it was discharged to the CW and (ii) the CW type - with surface flow of leachate (FWS). At the sub-surface flow wetlands (Szadółki, Gatka), clogging problems occurred due to lack of or unsatisfactory pre-treatment of leachate, resulting in lower treatment efficiencies. The ammonia nitrogen was still removed at the clogged facilities with the efficiencies varying from 52 to 89%, while the organics removal efficiencies were substantially lower (27 - 61% for BOD5 and 2-35% for COD).

Authors (3)

Ewa Wojciechowska prof. dr hab. inż.
Magdalena Gajewska prof. dr hab. inż.
Hanna Obarska-Pempkowiak prof. dr hab. inż.

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Category:: Articles
Type:: artykuł w czasopiśmie wyróżnionym w JCR
Published in:: POLISH JOURNAL OF ENVIRONMENTAL STUDIES no. 19, pages 643 - 650,
ISSN: 1230-1485
Language:: English
Publication year:: 2010
Bibliographic description:: Wojciechowska E., Gajewska M., Obarska-Pempkowiak H.: Treatment of landfill leachate by constructed wetlands: three case studies// POLISH JOURNAL OF ENVIRONMENTAL STUDIES. -Vol. 19, nr. nr 3 (2010), s.643-650
Verified by:: Gdańsk University of Technology