Choosing a greywater pumping system

Just water Savers has manufactured and sold over 6,000 water re-use systems. We have also attended hundreds of greywater diversion system installations. So we believe we have a good idea of what works - and what doesn't work.
 
There are a lot of greywater diversion systems on the market right now. And in our opinion there are systems with a lot of problems . Normally in business you do not focus on the negatives found with other products. However we believe you should know.

   
Special Note: Holman Arid
 
The Arid greywater system deserves special mention. Instructions state the Arid may be connected to household fixed waste plumbing (eg shower wastes) by licenced plumbers. The packaging  box also shows images of the product connected to standard DWV waste plumbing pipes. Holman representatives have also been on radio saying it can be connected to shower waste.
 
Although the Arid has 40mm DWV (drainage, waste and vent) inlet and overflow connections, the pipes passing through the wall of the unit reduce to 25mm or less, severley restricting water flow. Because of this plumbers cannot connect an Arid system to household plumbing without risking their licence.
 
The plumbing regulations are there for a reason -  devices such as the above create a very high risk of waste water backflow within the house ie flooding.

 

 

The following is a list of problems that are inherent in some products available in the market right now:

• Electronic Controllers:
   
  Regulations state that greywater must not be stored for more than 24 hours. To solve a technical pump issue, some diversion systems use a water probe to detect water levels in the pumping unit. This probe has two floating collars that act as electronic switched. To work effectively, these collars must be able to move up and down a small section of the probe freely.
   
  Because greywater is sticky, this probe must be cleaned every two weeks, or the pump will not turn on, or worse, will not turn off and will seize.
   
  The EcoBowser does not use any electronics - it is Watermark approved for use throughout Australia, without the need for electronics.

• Internal Filters:
   
  Apart from being extremely messy and unpleasant to clean, internal filters are a major cause of lost greywater.
• Internal filters are almost always placed between the plumbing inlet and the pump. Therefore the greywater only moves through the filter by gravity. As foreign materials get caught in the filter, the greywater slows down in its passge through the filter.
   
  Many systems have small entry chambers, so if 20 litres of water per minute is coming into the system (from a shower or washing machine), it cannot pass through the filter quickly enough. So the water level rapidly rises in the entry chamber and flows out the overflow pipe, and down the drain.
   
  The EcoBowser filter is located outside the pumping unit, after the pump. Because water is forced through the filter, water is not lost in this way.

• Single 50mm Plumbing Inlet:
   
  In the vast majority of installations, it just makes sense to connect at least two greywater sources, if not more. Any diversion systems that only has one 50mm inlet may only be connected to one greywater source.

• Single 65mm Plumbing Inlet:
   
  If the diversion system has a 65mm inlet, more than one greywater source can be connected (this is good). However the plumbing required to bring water from two or more different waste pipes, together with installing 65mm diverters can be very time consuming ie expensive.
   
  The EcoBowser is designed in such a way the plumber can create as many inlets as required, anywhere on the EcoBowser.

• Self Cleaning Systems:
   
  Diversion systems that claim to be self cleaning generally use a significant percentage of the greywater to flush lint and hair back down the sewer pipe. The remaining water still contains a lot of small to medium particles that will clog the internal or external filters, and as such will still require regular cleaning. In our opnion the removal of lint and hair from the water will not reduce the amount of manual filter cleaning required.  Sludge buildup will still occur in the bottom of most of these sytems.

• Insufficient Pump Protection:
   
  If the pump outlet becomes blocked (eg full external filter) or closed external valves, water cannot pass through the pump, and it will rapidly heat up the small amount of water inside the pump, causing the bearings to sieze. In the last two years other systems have started using special pressure sensitive valves to detect a blockage, and we tried it as well. Unfortunately these valves do block with greywater matter, and require cleaning regularly.
   
  The EcoBowser includes an always open pressure relif tube that is not troubled by greywater matter. Also this tube causes water to vigorously circulate within the EcoBowser, so sludge buildup does not occur.

• Use of Irrigation Systems other than Drip LIne:
  
  There are two main types of alternative irrigation methods:

• Large diameter slotted tube, buried in a trench, below shrub root level. Becuase the tube is well below garden bed surface level, most of the water simply drains down into the subsoil. This is good for Trees (deep roots) but is not effective for shrubs and general plants.

• Water Pods, supply line is used to carry water from the diversion system to a number of pods placed around the garden. In our opinion this is significantly inferior to greywater drip line. The water is concentrated in certain areas, creating the risk of over watering and concentration of greywater contaminants in those areas.

          Just Water Savers only recommends greywater dripline for even water distribution.
  

• Gravity Fed Irrigation Systems:
   
  There are a number of systems that pump water up to a header tank and then use gravity to supply the irrigation system. Gravity does not provide sufficient pressure to ensure even water distribution across the irrigation network, unless greywater dripline (eg Tiran) is used. Other methods, or using gravity alone with dripline over an extensive garden will result in uneven irrigation.
   
  The EcoBowser provides sufficient pressure to maintain the same drip rate 200 metres away from the EcoBowser as 1 metre away.