The Good Life - Off Grid Water Solutions and Water Neutrality

If you're thinking of escaping the smog of modern day commercial living in exchange for a more peaceful existence we've prepared a quick guide for those essential off grid water supply and treatment considerations. 

Water Supply

The vast majority of homes in the UK are connected to a central water supply, operated by their local utility company. However, around 1% of the population in England and Wales use a private water supply (PWS); in Scotland this figure increases to 3%.

Groundwater or River Abstraction as a Water Supply

Many properties with a PWS have a ground water supply usually fitted with a borehole well pump. Being off grid the benefit of a solar water sumbersible well pump is clear. Likewise the motion of flowing water can actually be used in a ram pump set up. The Papa Ram Pump is one such innovation which allows the momentum of flowing water to power the pump and so an external power supply is not required. This set up is ideal to fill a header tank and using this header tank to discharge to the site on demand.

If a new borehole or alternative abstraction is to be implemented this will be subject to building control and the Environment Agency (or SEPA) will be involved at the early stages to ensure the borehole/abstraction has no negative impacts on the existing groundwater/river.  

Rainwater as a Water Supply

Capturing Rainwater is something that any household or business can do but if you are thinking of living off grid this becomes particularly important. Any roof space can become source of water supply. By simply installing a water storage tank, whether that be above or below ground, a large amount of water that would otherwise go to waste can quickly be collected and stored until necessary and delivered on demand to where it is required using a rainwater harvesting system. Considering a gravity rainwater harvesting system reduces the power demand on the site and makes off grid living that much more achievable.

Whilst rainwater itself is not suitable for drinking directly after harvesting, there are a number of products that will divert and filter the rainwater to an acceptable standard for flushing toilets which typically represents 30% of total household demand increasing to 45% if washing machine usage is added. Splitting out potable and non potable demand has a significant effect of reducing the demand and sizing of the potable water system and often pays for itself. 

In terms of sizing our online rainwater harvesting calculator  will help for most domestic and smalls scale projects. If the project is more substantial you may wish to consider a level 3 rainwater harvesting assessment.

Storage of Water. 

Once a source has been identified the water can be collected and stored in its raw form with the the treatment step downstream of the holding tank. If stored after treatment a potable water tank will be required. A combined potable tank and booster pump set can be incorporated into the system to ensure short durations of high water demand are well managed. This tank is typically much smaller than a main raw/source water tank. This step (potable water storage) may not be required if the treatment capacity exceeds the maximum demand.

Water Treatment for Drinking

In some cases however a total off grid solution is required since no other source of water exists and so rainwater purification system is required.

Water that is intended for drinking understandably comes under the most stringent of regulations.

Typically treatment  for drinking water starts with analysis of the incoming water to establish the baseline using water quality testing.

Once the baseline has been established the treatment can tailored to suit. 

In all cases a particle/sediment filter(s) followed by a carbon filter will be required. This will remove all particles typically down to 5 micron and the carbon filter will remove taste and odour issues. 

This will be followed by a Ultraviolet (UV) light to kill bacteria - the size on this will depend on the maximum flow rate required typically 20-30 lpm in a domestic setting. 

A WRAS approved booster pump set maybe required  to store water, balance demand and maintain pressure. 

Further water treatment may applied depending on the baseline assessment, this may include Reverse Osmosis membrane filters.

The above treatment chain can be supplied in an "all in one package"  such as the Rainsafe or Ozo-Pure, an innovative rainwater to drinking water package solution for treating rainwater into drinking water, storing it and delivering it on demand. 

For drinking water treatment on the move a UV LED water bottle could be a worthwhile investment.

Waste Water Treatment and Grey Water Recycling

There are a number of activities that result in wastewater being created, domestically these could include cooking, bathing, washing, using the toilet. 

As with the benefit of splitting out incoming water into potable and non potable uses it is worth considering the different types of waste water. 

Grey water represents up to 70% of wastewater output resulting from showers, baths and taps and thus a potentially great resource. We supply the Hydraloop  which is a package system which treats grey water to a non potable standard suitable for flushing toilets. A simpler alternative for greywater recycling is the Manhattan Greywater recycling system.  This system is completely passive and requires no external power, the key component of the system is powered by solar. This system was developed for irrigation but could be adapted to flush toilets also using a micro on demand pump.

96% of the UK’s wastewater is treated at large scale waste water treatment plants. This is completed in the following stages:

• Preliminary treatment
• Primary treatment
• Secondary treatment
• Tertiary treatment 

In an off grid scenario the waste water must be treated to a standard where it can be discharged to a drainage field or a water course. New legislation in the UK requires all new properties and existing properties with a septic tank to be upgraded to a package treatment plant or a small sewage treatment plant. 

There are also a number of solutions that can be installed on a more local level, such as a GRAF One2Clean domestic sewage treatment plant which treats wastewater to a very high standard allowing it to be discharged to the water course with minimal environmental impact. 

Living in the 'sticks' is dream for many but it does present some challenges: where will the water come from, how should it be treated for drinking and  how will the wastewater be dealt with. Whatever the challenges we have a solution. Most the technologies described above are available for inspection at the Centre for Water Saving technology.

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