Nutrient Reduction potential of

Transcription

1 Nutrient Reduction potential of

2 Nutrient Reduction potential of Global importance of Wetlands Classification of wetlands Types of activities on Wetlands Reduction potentials of Wetlands Pros and Cons using Wetlands for Nutrient Reduction The Political/Economical/Social importance of Wetlands

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4 Classification of wetlands Natural wetlands (swamps, marshes and similar areas along edges of water bodies) Rehabilitated Wetlands (pulling out dikes, redirecting streams and rivers, stopping intensive agricultural practices) Constructed Wetlands (A modified natural or constructed shallow basin for treatment of contaminated waters by wetland vegetation)

5 Nutrient reduction using wetlands Using natural wetlands to clean wastewater (Discharging directly into Wetlands, little alteration in the natural dynamics, not able to target specific types of wastewater, mainly used for Construction of tertiary treatment) Wetlands to clean wastewater (Artificially created wetland with optimized functions for cleaning specific types of wastewater)

6 Constructed Wetlands Horizontal Flow System Vertical Flow System

7 Nutrient reduction: Wetlands contra Conventional Chemical/Biological efficiency of Wetlands Free Water Syst. Subsurface Water Syst. Conventional Efficiency BOD Good (80%) Good (70-80%) SS Good (80%) Very good (80-90%) N Mediocre (65-70%) Mediocre (70%) P Limited (50%) Limited (50%) ColiForm Such results can only be reached using a combination of low tech solutions: P - needs calcium rich post-treatment filtration BOD - needs a well-activated sludge pre-treatment N - needs a thorough post-treatment aeration

8 BOD, N & P Reductions % 80.00% 60.00% 40.00% 20.00% wastewater 0.00% Household seweage, Tanzania Dairy, Colombia Printing, (Newspaper)*, Colombia Flower production**, Colombia Tanneries, (Leather prod.)***, Colombia Slaughter house, Colombia Household Seweage, Denmark Domestic and industrial, Egypt UNDP/GEF Cheese factory, France N % P % BOD %

9 Wetlands contra Conventional Social/Cultural aspects Free Water Syst. Subsurface Water Syst. Conventional Area needed per PE High 2 m 2 15 m 2 High 1-10 m 2 Is a minor issue Animal infestation risk high Medium low Odor nuisances high Low Low Mosquito breeding High Low Low Cold climate stability Mediocre High High Inclusion of the public Crucial Crucial Important

10 Wetlands contra Conventional Political and financial Aspects Free Water Syst. OM skills needed Low Investment indexed Operation US$ (1998) 1000 PE 7500 Depreciation of invest. 20 yr Subsurface Water Syst. Low yr Conventional high yr

11 The Political/Economical/Social importance of Wetlands Local (Water security, Food, money generation, health) National (Impact on national water ways, health, political stability) Regional ( e.g. Lake Vic, Black Sea, social, economical and political stability) International (Strategic importance for GEF, WB, UNDP etc.)

12 GEF Funded Wetland projects Country Albania/ Macedonia (UNDP) Bosnia-Herzegovina (WB) Bulgaria (WB) Project Name Integrated Ecosystem Management in the Prespa Lakes Basin of Albania, FYR-Macedonia and Greece Water Quality Protection Project Wetland Restoration and Pollution Reduction Project Type of action (among others) Construction of SFS/FWS systems Combination of constructed SFS, FWS and Natural wetland systems Rehabilitation of Natural Wetlands China (WB) Ningbo Water and Environment Combination of constructed SFS, FWS and Natural wetland systems Egypt (UNDP) Hungary (WB) Lake Manzala Engineered Wetland Reduction of Nutrient Discharges Combination of constructed SFS & FWS wetland systems Rehabilitation of Natural Wetlands Moldova (WB) Agricultural Pollution Control Project Rehabilitation of Natural Wetlands Uganda/Tanzania/ Kenya(WB) Lake Victoria Environmental Management Project Combination of constructed SFS, FWS and Natural wetland systems

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