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Domestic Reed Bed Systems

In Australia, more than 13% of the population (more than 2 million people) rely on on-site wastewater treatment systems. 

"On-site" means that these wastewater systems manage the human wastes and wastewater from households totally on the property.

More than 250,000 systems have been installed, and most of these use septic tanks. Other types of systems consist of aerobic treatment where air is forced into the effluent water body to accelerate biological processes.

All systems require appropriate disposal on-site (or in some circumstances, off-site) of the resulting treated water. 

Past investigations in some states in Australia have shown that there are thousands of properties with septic tank systems that have failed. Many of these properties are located in sensitive catchments where the quality of rainfall runoff needs to be maintained to as high a level as possible for human consumption. 

Every major city in Australia is reliant on water that falls on catchments outside the metropolitan areas. These catchments serve not only human drinking water purposes, but also sensitive ecosystems. 

Septic system failure is preventable if proper design and understanding of natural systems, understanding of soil characteristics, and use of appropriate technology, are all applied together.


REED BED WASTEWATER TREATMENT

Look along the edges of watercourses, creeks, and wetlands. What do you see? Reeds … natural aquatic plants that trap sediments and clean up the water body of contaminants. 

That is precisely the principle used in domestic reed bed wastewater treatment. It is a natural process. 

In a single house or perhaps a group of several houses in a community setting, a reed bed is fundamentally a constructed wetland for the secondary treatment of septic tank effluent. 

Note that a septic tank (a primary treatment process) is absolutely necessary to detain the solids, oils, and grease that are discharged from the household.

The reed bed could be a trench that is lined with an impermeable membrane, or it may consist of shallow troughs inserted into the ground. In some cases where topography is suitable, the troughs could be placed on the ground surface. 

Here are two of my designs.


A large-scale trench reed bed in the early stages of operation


  

A trough reed bed system prior to planting out with reeds


As you can see in the photos above, one of the most important parts of a reed bed is the gravel that supports the reeds. Next are two examples of fully grown domestic reed beds that have been functioning for many years.

Reed bed


Greywater reed bed


How does a reed bed work?

Raw wastewater in the septic tank undergoes primary treatment to remove large solids, grease and oils. This is essential, as any of these materials can clog the reed bed and ultimately decrease it's effective function.

Wastewater from the septic tank passes through the root zone of the reeds where it undergoes treatment via physical, chemical and biological interactions between the wastewater, plants, micro-organisms, gravel and atmosphere.

The resulting treated water is then discharged safely to sub-surface irrigation.

NATURAL PROCESSES + WATER RE-USE  =  ENVIRONMENTAL BENEFITS




Where can a reed bed system be used?

Domestic reed bed systems are suitable for the following;

  • rural properties on peri-urban (i.e. on the fringe of towns) land
  • property owners seeking a natural wastewater treatment system
  • sites that have had a soakage type disposal system that has failed and needs upgrading because of various problems such as soil structural collapse 
  • land located in sensitive catchments that should have secondary wastewater treatment as a minimum


Want to find out more?

THE REED BED BOOK ON NATURAL WASTEWATER MANAGEMENT

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