Water Harvesting

Water harvesting reed beds
Water harvesting reed beds

My homemade reedbed

 

My homemade reedbed water harvesting project

 

Project overview
Project: Grey water reclamation at home
Client: Me / Planet Earth
Cost / Value: “Undisclosed”
Programme: Spring 2006 – Spring 2007
Client’s Requirements: How to beat the hosepipe ban and save the planet
The inspiration and research: Article on Monday, 13 March 2006

 

 Article on Monday, 13 March 2006, extracted from BBC News.

Hosepipes banned by Thames Water

 

Hosepipe ban
Britain's biggest water company will ban hosepipes and sprinklers from next month, the firm has announced. Thames Water, whose eight million customers will be affected by the ban, says two unusually dry winters have caused "serious" water shortages. The South East has experienced its driest period for more than 80 years

 Rainfall graph

  I used the water usage calculator on the BBC website and estimated that my family uses approximately 400lts of water per day. That equates to 133lts per person which compares favourably to the national average of 155lts per day. Of this about 60% is for showers and baths. However, the above calculation did not include the irrigation system that I have in the garden. I recalculated the water usage including use of a hosepipe to water the garden, but for a reduced time to account for the difference between a hose pipe and irrigation system rate of flow. This added 90 lts per day. Coincidently the water used for showers and baths equates to 80 lts per day.

We already did some water conservation by collecting rain water using a single water butt and leaving the grass to grow a little longer, and not watering it. So it seemed a simple solution to use the bath waste water to water the garden. At this point I should have just decided to have showers with the plug in and siphon out the water with a hose after it had cooled. As sane people eventually did. You can even now buy special products specifically designed to make it easier.

 However, I decided to research the possibility of creating a grey water reclamation system using reed beds. The local library proved, yet again, to be a good source of information, as did the internet. I learnt,

  • that different reeds deal with different pollutants and pathogens,
  • about aerobic and anaerobic digestion
  • micro-organisms, bacteria, fungi, and protozoa
  • surface or subsurface, horizontal or vertical flow configuration
  • rainfall patterns throughout the year
  • rate of flow through reed beds
  • and area of reed bed required per person
  • Pollutants and pathogens are removed from the waste water flowing through a reed bed by a complex variety of physical, chemical and biological processes, including aerobic and anaerobic microbial activity, nitrification, plant uptake, sedimentation, precipitation and filtration.
  • Reed beds are successfully and economically used in full scale black water sewage treatment and industrial effluent treatment.

Importantly reed beds require little maintenance, no additional chemicals, little or no energy dependent upon the site geography / topography and are of course, completely natural. 

 


Conclusion

In conclusion this has been a very rewarding project involving a number of different ‘green’ techniques to provide a solution to a specific problem. Albeit that this problem has yet to occur this year, the system is still working very well, producing crystal clear water day after day, whatever the weather. I have not had the water tested to be able to categorically state its quality, but suspect that it is actually potable. I believe that it has significantly reduced the family’s carbon footprint and provided interest and ongoing enjoyment.

I have added two narrow water butts at the front of the house to capture rainfall from those elevations. The water butts are small and relatively unobtrusive. It is however sufficient to be a surge tank and to accommodate the build-up during downpours which is free to flow via a garden hosepipe to the reed beds in the back garden, after keeping back enough in the second tub to water the pots in the front garden. The rain water flush provide by the front water butt and the brick shed cistern also reduce the systems maintenance requirement.

Another development to be considered is the adaptation of the WC supply to be both mains and reclaimed water. This would further reduce our mains water consumption.

Finally my thanks to the books and internet articles that provided the invaluable reference material that made this project possible.


 

 

Updates

 

June 2010

August 2020

  • Transfer from old site to this one
  • Photos re-mastered
  • Some additional photos, Figure numbers with sufix.
  • Minor text corrections

 December 2021

  • Added tabs to aid reading
  • Incorporated this article inside another

 



 

 

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