Introduction

Whole Systems Approach to Ecological Design

Appropriate Technology: Water

Organic Agriculture and Local Food

Appropriate Technology: Energy

Green Building & Retrofitting
Appropriate Technology: Water

Tank Based Systems

Tank-based technologies take waste into a single or series of tanks, where controlled short retention time treatment takes place (in typically six hour cycles).  The Organica approach described below is a good example of an ecological engineering approach to tank based design.

Constructed wetlands and lagoon-based systems are located in the open and usually have a high physical footprint and low ecological footprint.  In wastewater treatment physical size can be traded for energy.  Tank based systems are more highly engineered, are of a smaller size and use larger amounts of energy.  The chart in “Suitable treatment for sustainable communities” illustrates this.

Organica of Hungary - Fed Batch Reactor (FBR)

Organica has combined natural treatment biology with a highly engineered and computer-controlled mechanical technology to provide the most advanced expression of an ecologically engineered wastewater treatment system.  This is the most suitable for systems larger than 3,000 pe to be installed in an urban location.  The physical footprint is a fifteenth the size of a constructed wetland.  It is a trade-off between land used and investment plus operating energy. (www.organica.hu)

The system has the following characteristics:

  • Attached growth treatment with planted ecologies and manufactured media;
  • Suspended growth treatment;
  • Anaerobic, anoxic & aerobic batch cycles;
  • Nitrification in aerobic and denitrification in anoxic cycles;
  • Luxury uptake of phosphorous;
  • Blowers controlled by dissolved oxygen sensor activation of variable frequency drives.

The system runs four treatment cycles a day.  The short retention time results in a low physical footprint.  Finely tuned treatment cycles are controlled by a computer that can be accessed remotely.

High efficiency aeration blowers have variable frequency drives and dissolved oxygen sensors enable the process computer to optimise energy performance.

FBRs provide high levels of treatment performance.  Here the average annual BOD was 8.2 mg/l with a highly variable influent, demonstrating the robustness of the system.

BOD Performance

BOD Performance
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In countries with cold winters, FBRs are installed in greenhouses: 8,000-pe system outside Budapest

The planted ecologies make the greenhouses look like botanical gardens.  A wide diversity of plants is grown.

The root mass in the reactors provide excellent attached growth treatment.

FBRs can be installed in urban locations, as there are no odours.

Typical cross-section of the greenhouse and tanks.
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