Introduction

Whole Systems Approach to Ecological Design

Appropriate Technology: Water

Organic Agriculture and Local Food

Appropriate Technology: Energy

Green Building & Retrofitting

Lagoon-based natural treatment system with floating ecologies

This system works on similar aquatic biological principles to constructed wetlands.  However it uses energy to supply aeration and mixing, is more highly engineered and has a smaller physical footprint.  It has five components:

• Floating Structure, that supports the active systems
• Aeration, either fine bubble or submersible venturi
• Floating planted areas, with roots in the water
• Geotextile media for enhanced attached growth treatment
• Biaugmentation, as necessary

This lagoon system has a smaller physical footprint than a constructed wetland with the same loading.  Operating costs are higher because aeration is used.  The systems can be designed to provide minimum sludge, where sufficient retention time is available, which could mean a larger lagoon.  The sludge is digested as part of the lagoon ecology.  Sludge removal every ten years is achievable.

(www.floatingislandinternational.com, www.lookfar.org/institute.html)

How does a lagoon system compare with “conventional” technology such as activated sludge?

• Lower Capital Cost
• Robust and Simpler systems to operations, owing to cascade operations
• Lower energy required for operations
• Substantially less sludge
• Combination of the above means lower operating costs, and
• Lower life cycle costs
• Uses more land
• Beautiful systems that are natural.

• Lagoon Based Systems
• Tank Based Systems
• Suitable treatment for sustainable communities
• Energy and Carbon Footprinting

Floating ecology and aeration in an industrial treatment lagoon

Baffles direct flow through the lagoon
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Automated HDPE but-welding machine

Fine bubble aeration provided by a membrane aerator