Specialist Group on Use of Macrophytes in Water Pollution ... - IWA

Recommendations

Info

Figure 2 Plant condition in constructed wetland treating young leachate (left) and stabilized leachate (right). Greenhouse gas emission during the treatment Greenhouse gases emission from the HSF unit was measured by close-flux chamber method. The close flux chamber has 0.3 m diameter and 0.3 m height. The base of chamber was made of stainless steel with 0.3 m diameter and 0.125 m height. The gas sampling was regularly conducted during 2 hours after the installation of chamber during which gas concentration gradient in the chamber relates directly to the its emission rate. The emission of methane gas was ranged between ND level up to 0.71 g/m 2 .d. The maximum emission rate was found highest at inlet zone and reduced along the flow. The emission of greenhouse gas was also found varied seasonally. During rainy season, the emission was found lower as considerable amount of rain diluted the water in the system thus led to lower methane emission. Methane emission was comparable higher during summer under elevated temperature. Introduction of internal recirculation in the system also helped reducing greenhouse gas emission. More detailed information can be found in Chiemchaisri, C. et al., Leachate treatment and greenhouse gas emission in subsurface horizontal flow constructed wetland. Bioresour. Technol. (2009), doi:10.1016/j.biortech.2008.12.028. ___________________________________________________________________________ 16 IWA <strong>Specialist</strong> <strong>Group</strong> on Use of Macrophytes in Water Pollution Control: Newsletter No. 35
ESTROGEN REMOVAL IN WETLANDS – REVIEW Dana Milstein a , Avital Gasith a and Dror Avisar b a Faculty of Life sciences, Department of Zoology, Tel Aviv University, Israel b Geography and Human Environment, Hydrochemistry Laboratory, Tel Aviv University, Israel One of the key environmental problems facing humanity emanates from the widespread and diverse contamination of freshwater (Schwarzenbach et al., 2006). New contaminants are continuously being identified and become the focus of new investigations. Recently, micropollutants were recognized as a threat to the integrity of aquatic environments (Schwarzenbach et al., 2006). These pollutants are compounds that are present in the environment in minute concentrations (micro and nanograms per liter) and thus are hard to detect. Known micro-pollutants include chemicals for human use such as pesticides, pharmaceuticals and cosmetic products. Such contaminants reach aquatic systems and soils together with the effluents and sludge that are discharged into the environment (Shore et al., 1993; Ingerslev and Halling-Sørensen, 2003). The presence of estrogens in primary and secondary effluents reveals that they are not completely removed by conventional wastewater treatments (Kreuzinger et al., 2004; Pawlowski et al., 2004; Kolodziej et al., 2003). Developing and implementing cost-effective wastewater treatment technologies to remove micro-pollutants is therefore a major challenge (Schwarzenbach et al., 2006). Here we review the current knowledge on the removal efficiency of estrogens from municipal wastewater effluent by environmentally friendly, wetland technology. Findings of our recently completed research are included (Milstein et al., in preparation). Estrogens Estrogenic compounds are lipophilic; natural or synthetic molecules. Natural estrogens such as estrone (E1), 17�-estradiol (E2) and estriol (E3) are synthesized in the vertebrate body. Synthetic estrogens such as 17�- ethinylestradiol (EE2) and mestranol (MeEE2) are used as pharmaceuticals (e.g., contraceptives). There is evidence that at the low concentrations at which these compounds are present in the environment they interfere with normal endocrine activity (e.g., Tyler and Jobling, 2008). One of the earliest pieces of evidence for the biological effects of estrogenic compounds found in the environment was that of the increase of a precursor molecule for egg yolk synthesis (vitelogenin) in plasma of male fish (e.g. Lintelmann et al., 2003). In addition, inhibition of testicular growth and diminution of secondary sex characteristics of male fish were reported (Jobling et al., 1996; Jobling et al., 2002). There is evidence that invertebrates too (e.g. molluscs and crustaceans) are affected by exposure to estrogenic pollution originating from vertebrates (Jobling et al., 2004; Gagne et al., 2003; Segner et al., 2003; Czech et al., 2001). Potential mechanisms for estrogen removal in wetlands Physical, chemical and biological processes attenuate organic compounds in wetlands (Imfeld et al., 2009). These processes involve evaporation, photo-chemical oxidation, sedimentation, sorption, and biological degradation mechanisms (e.g., Kadlec, 1992; Imfeld et al., 2009). Little is known on the relative contribution of each mechanism to the removal of organic compounds (Imfeld et al., 2009). Moreover, the relative importance of a particular process can be expected to vary, depending on system attributes such as wastewater quality, flow pattern (surface flow, sub-surface, horizontal or vertical flow), operational variables (e.g. ____________________________________________________________________________________________________ IWA <strong>Specialist</strong> <strong>Group</strong> on Use of Macrophytes in Water Pollution Control: Newsletter No. 35 17
Page 1 and 2: Specialist <strong
Page 3 and 4: PREFACE BY THE SECRETARY Dear Membe
Page 5 and 6: ___________________________________
Page 7 and 8: ___________________________________
Page 9 and 10: ___________________________________
Page 11 and 12: UNCLOGGING THE FUTURE OF TREATMENT
Page 13 and 14: Paul Knowles (Aston University) and
Page 15: APPLICATION OF CONSTRUCTED WETLAND
Page 19 and 20: Prado wetland (Xie et al., 2004) by
Page 21 and 22: estrogens were adsorbed to suspende
Page 23 and 24: Matamoros, V. and J.M. Bayona (2008
Page 25 and 26: Table 1 - Water withdrawal in Italy
Page 27 and 28: Integrated system of multifunctiona
Page 29 and 30: Rovigo Province Landfill Site Leach
Page 31 and 32: administrative, ―political‖ or
Page 33 and 34: The CW sector is formed by a sedime
Page 35 and 36: References and Bibliography Barbaga
Page 37 and 38: Table 1. Domestic wastewater of the
Page 39 and 40: awareness on the importance of wate
Page 41 and 42: The IWA Water Wiki! Call for Contri
Page 43 and 44: The book covers: � handling of re
Page 45 and 46: Looming threats such as climate cha
Page 47 and 48: The findings and recommendations of

Specialist Group on Use of Macrophytes in Water Pollution ... - IWA

Create successful ePaper yourself

Delete template?

Save as template?