TAILIEUCHUNG - Monitoring and assessing processes of organic chemicals removal in constructed wetlands

The Committee is composed of representatives of the National Standards Bodies in Partner States, together with the representatives from the private sectors and consumer organizations. Draft East African Standards are circulated to stakeholders through the National Standards Bodies in the Partner States. The comments received are discussed and incorporated before finalization of standards, in accordance with the procedures of the Community. East African Standards are subject to review, to keep pace with technological advances. Users of the East African Standards are therefore expected to ensure that they always have the latest versions of the standards they are implementing | Chemosphere 74 2009 349-362 Contents lists available at ScienceDirect Chemosphere journal homepage locate chemosphere Review Monitoring and assessing processes of organic chemicals removal in constructed wetlands Gwenael Imfelda Mareike Braeckeveltb Peter Kuschkb Hans H. Richnowa a Department of Isotope Biogeochemistry Helmholtz Centre for Environmental Research - UFZ Permoserstr. 15 Leipzig D-04318 Germany b Department of Bioremediation Helmholtz Centre for Environmental Research - UFZ Leipzig D-04318 Germany ARTICLE INFO ABSTRACT Article history Received 7 March 2008 Received in revised form 11 September 2008 Accepted 12 September 2008 Available online 8 November 2008 Keywords Biogeochemistry Remediation Phytoremediation Degradation Volatilization Integrative approach Physical chemical and biological processes interact and work in concert during attenuation of organic chemicals in wetland systems. This review summarizes the recent progress made towards understanding how the various mechanisms attributed to organic chemicals removal interact to form a functioning wetland. We also discuss the main degradation pathways for different groups of contaminants and examine some of the key characteristics of constructed wetlands that control the removal of organic chemicals. Furthermore we address possible comprehensive approaches and recent techniques to follow up in situ processes within the system especially those involved in the biodegradationprocesses. 2008 Elsevier Ltd. All rights reserved. Contents 1. Introduction. 350 2. Removal processes in constructed wetland. 351 . Non-destructive . Volatilization and phytovolatilization. 351 . Plant uptake and phytoaccumulation. 351 . Sorption and sedimentation. 352 . Destructive . Phytodegradation. 353 . Microbial degradation. 353 3. Metabolic potentials of constructed wetlands. 354 . Redox processes at the constructed wetland system .

• Hoá học
• Transkei
• Ciskei
• rural
• peri urban and urban consumers on the reasons for not consuming organic products
• The two main reasons advanced is that organic products are expensive according to 60% of the consumers in the Transkei
• 54
• 2% of consumers in the Ciskei
• 62
• 5% of peri urban consumers and 81
• 8% of urban consumers (see Table 1)
• The second reason advanced is that organic products are not readily available according to 60% of the consumers in the Transkei
• 70
• 8% of the consumers in the Ciskei
• 80% of rural consumers
• 62
• 5% of peri urban consumers and 63
• 6% of urban consumers (see Table 1)