Grey Water Systems

GREY WATER SYSTEMS

General Information

The average bath produces 120l of water, a shower 80l and the washing machine 100l per load. This water has to be redirected from the various sources via 50mm pipe to a central point. The water then runs through a gravity filter and is automatically pumped to the garden first via irrigation pipe and then multiple garden hoses and Gardena sprinklers.

Recycling of grey water can reduce your total water needs by approximately 50 %:

Lower fresh water use

Grey water can replace fresh water in many instances, saving money and increasing the effective water supply in regions where irrigation is needed. Residential water use is almost evenly split between indoor and outdoor. All grey water except kitchen water could be recycled outdoors, achieving the same result with significantly less water diverted from nature.

Less strain on septic tank or treatment plant

Grey water use greatly extends the useful life and capacity of septic systems. For municipal treatment systems decreased wastewater flow means higher treatment effectiveness and lower costs.

Highly effective purification

Grey water is purified to a spectacularly high degree in the upper, most biologically active region of the soil. This protects the quality of natural surface and ground waters.

Site unsuitable for a septic tank

For sites with slow soil percolation or other problems, a grey water system can be a partial or complete substitute for a very costly, over-engineered system.

Less energy and chemical use

Less energy and chemicals are used due to the reduced amount of both freshwater and wastewater that needs pumping and treatment. For those providing their own water or electricity, the advantage of a reduced burden on the infrastructure is felt directly. Also, treating your wastewater in the soil under your own fruit trees definitely encourages you to dump fewer toxic chemicals down the drain.

Groundwater recharge

Grey water application in excess of plant needs recharges groundwater.

Plant growth

Grey water enables a landscape to flourish where water may not otherwise be available to support much plant growth. This in turn reduces the amount of thermal radiation and helps to reduce the greenhouse effect.

Reclamation of otherwise wasted nutrients

Loss of nutrients through wastewater disposal in rivers or oceans is a subtle, but highly significant form of erosion. Reclaiming nutrients in grey water helps to maintain the fertility of the land.

Overview of the Installation

In short, we are going to plumb the entire site to collect the water from every bath, shower, hand basin and clothes washing machine. This water is then filtered and used to irrigate your garden.

The installation requires one underground tank and filter as well as the redirecting of the waste water from the baths, showers and hand basins for distribution into the garden. During this process one new external electrical point will be fitted to provide power to the underground pump. We will place sprinklers and hoses.

In Cape Town alone there are more than 3500 houses using grey water to water their gardens every day. But this is small compared to a place like Santa Barbara California in the USA. Out a possible 200,000 people 40% use grey water systems.

FAQ

TOP

1. Where would the pump chamber be installed?

2. The piping needs to be concealed within the walls, is this possible?

3. What are the implications regarding any toxic levels to the plants?

4. Will you be providing piping to the storage tanks or do we provide the piping?

5. How much does the system cost?

6. What does the system contain?

7. What is involved in the installation?

8. If I have a Fynbos garden what should I use?

9. Can I use my irrigation that I already have?

10. Do I have to move a hose around al the time?

11. What size pump do you use?

12. Can I mix the rain and the grey water?

13. Can I store the grey water in a larger tank?

14. How long does the system take to install?

15. Does the grey water smell? If YES, can we eliminate this smell?

16. Why did the quote only include three bathrooms? There are in fact five bathrooms areas:

17. Is the grey water bad for the garden? What detergents should I use?

ANSWERS:

TOP

Where would the pump chamber be installed?

The pump chamber would be placed underground at the closest collection point of all the water from the bathrooms and laundry areas. We provide new 50mm pipes to redirect the water to a central location, maintaining 1 in 40m fall.

The piping needs to be concealed within the walls, is this possible?

As far as possible the 50mm pipe is either placed under ground or inside walls, obviously this is better concealed if done during initial building stage.

What are the implications regarding any toxic levels to the plants?

The oldest installation is in Fishhoek. It has been in place for 11 years and is still watering the garden every day.

We do not use the water from the kitchen sink or the dishwasher, as both would adversely affect the garden. Certain softeners for the washing machine have long term affect especially on Fynbos, Conifers and Roses.

A local company Enchantrix now manufactures an environmentally friendly range of softeners and detergents. Washing powders contain a large amount of Phosphates used as displacement agents. These phosphates over feed the soil and combined with the rest of its contents tend to change the alkalinity of the soil and this condition is not favoured by Fynbos. Ecosoft/Enchantrix washing powder now produces a phosphate free powder making it far more environmentally friendly.

Even if you choose not to use environmentally-friendly powders it will only affect certain plants.

Will you be providing piping to the storage tanks or do we provide the piping?

We provide for a 100L Pump chamber placed under ground for which we provide the piping from where the waste pipes leave the building.

Grey water is never stored and must be used within 8 hours, unless treated/filtered. Our system switches on automatically and pumps the water as soon as +-50 litres are accumulated.

Storage options are available, but should be discussed with your agent.

How much does the system cost?

Houses vary so there is no set price on how much the system cost, but the basic system has an average cost of about R5 500.

What does the system contain?

	Pump, pump chamber, filter
	Plumbing for the bathrooms and laundry into one central point
	Electrical point outside for pump
	Irrigation and pyramid sprinklers for irrigating the garden

What is involved in the installation?

	Plumbing all points into central area
	Submerging pump chamber
	Irrigation
	Electrical point

A standard system would take a day to install.

If I have a Fynbos garden what should I use?

The rain water system would be best to have if you have a Fynbos garden.

Can I use my irrigation that I already have?

This can be done with certain type of irrigation. We place new 25 mm irrigation pipes around the edge of the garden and attach 20 mm garden hoses ,Gardena fitting and sprinklers. We do not put grey water into POPUPS or Microjets. Even with advanced filtering the system will clog after 3 years. The irrigation pump provides enough pressure and flow to produce 5 meter spays from 3 Gardena sprinklers simultaneously.

10.

Do I have to move a hose around al the time?

We supply multiple hoses and sprinklers, spread around the garden - each with it's own tap. Our pump is strong enough to pump through 4 Gardena sprinklers simultaneously, covering a large part of your garden at once. Large gardens would require the hoses to be moved, but only once every second day.

11.

What size pump do you use?

Our standard system comes with 850 watt pump and open impellor with a float switch attached, but depending on the installation it may vary from house to house.

12.

Can I mix the rain and the grey water?

We do not recommend running into a grey water tank automatically. What we do propose is storing rainwater in a separate rainwater tank and then letting the rainwater run into the grey water system when required.

13.

Can I store the grey water in a larger tank?

Its not recommended cause the grey water must only be stored at most 10 hours long.

For large complexes and/or larger properties, we can store grey water, but a water purification system must be added to clean the water.

14.

How long does the system take to install?

1 day for Grey Water System

15.

Does the grey water smell? If YES, can we eliminate this smell?

Grey water does produce a faint odour while irrigating, but the smell disappears within minutes after irrigating.

If you leave the pump off for a long period of time, there will be some settlement. The first time you switch it on there will be a pronounced odour. You can use a hose pipe to rinse off the sides of the tank after a while of no use. There is a slight odour when using it (as much as bath water smells).

16.

Why did the quote only include three bathrooms? There are in fact five bathrooms areas:

We have found that 95 % of the usable water gets produced from the laundry, main bedroom, onsite cleaning staff room and second bathroom (kid's room). We can most certainly include these additional areas but it may only be worth it if the house was fully occupied.

17.

Is the grey water bad for the garden? What detergents should I use?

No, grey water isn't bad for your garden unless you have Fynbos; detergents have phosphates in it which is actually good for you garden.

Ecosoft and Enchantrix make powders which are environmentally friendly (and low in phosphates) - making it safe for Fynbos and certain specialized plants.