This chapter discusses the history and use of constructed wetlands for wastewater treatment. It began with casual experiments in the 1970s, influenced by the rise of the green movement and concerns about energy use. Constructed wetlands provide advantages over conventional wastewater treatment by using natural processes powered by the sun instead of energy-intensive mechanical systems. For wetlands to effectively treat wastewater, certain prerequisites must be met, such as sufficient light, nutrients, space, and detention time. The chapter will cover the origin and evolution of constructed wetlands as well as their philosophy and worldwide applications.

1. Chapter one
Wetlands for Water Quality
History and philosophy of the
use of wetlands for
wastewater treatment

2. Wetlands for Water Quality
Learning objectives
• At the end of this chapter participants will be able to:
• Know something about the history of constructed
wetlands
• Know the prerequisites for treatment of wastewater in
natural systems

3. Chapter one
Contents
• Origin of constructed wetlands
• Advantages natural systems
• Philosophy and context
• Prerequisites of use of natural
systems
Wetlands for Water Quality

4. Chapter one
Wetlands for Water Quality
History and philosophy of the
use of wetlands for
wastewater treatment
By Professor Diederik Rousseau
University of Gent, Belgium

5. Tänassilma wetland
(Estonia)
OLC Constructed Wetlands

6. Origin of constructed wetlands
Use of wetlands for
wastewater treatment
Casual
experiments
+
(Kangas, 2004)
Rise of ‘green
movement’
+
First energy crisis
(1973)
+
OLC Constructed Wetlands

7. Comparison of the energy inputs to natural and conventional
wastewater treatment technologies
Natural systems Conventional systems
Sun
Wind Land
Seeds Concrete
Steel Electricity
Chemicals
Soils
Plants
Microbes
Microbes
Advantages of natural systems
OLC Constructed Wetlands

8. Use of wetlands for
wastewater treatment
Distrust of new
technogies
-
Casual
experiments
+
First energy crisis
(1973)
+
(Kangas, 2004)
Rise of ‘green
movement’
+
Origin of constructed wetlands
OLC Constructed Wetlands

9. Wetlands for Water Quality
(Kangas, 2004)Big bang model

10. (Kangas, 2004)
1970 Optimism and enthousiasm
1980 Cautiousness and scepticism
1990 Full-growing
2000 Commercialisation
Evolutionary phases of constructed
wetlands’ evolution
OLC Constructed Wetlands

11. Scandinavia
Bolivia
Vietnam
Canada
Australia
New
Zealand
Tanzania
Belgium
USA
India
South Africa
Application throughout the world
OLC Constructed Wetlands

12. Wetlands for Water Quality
Converting wastewater in useful products
Philosophy and context

13. Fish cum duck
Fish cum chicken
Fish cum pig
Example: wastewater aquaculture
OLC Constructed Wetlands

14. • Sufficient incident light
• Temperature not too low
• Adequate quantities of nutrients
• Waste water not toxic
• Detention time long enough
• Organic loading not too high
• Need for enough space
Prerequisites for natural systems
OLC Constructed Wetlands