Grey water reuse offers a wonderful opportunity for us to maintain the sort of gardens we want, without wasting a single drop of precious drinking water.
John Payne | Enviro-Friendly Products
by John Payne, Founder
Our local (Canberra, Australia) community is considering building a new dam, and that's a sad reflection on generations of government inaction, and individual indifference. Governments have taken little action to promote water conservation, even positively discouraging citizens from installing water tanks until comparatively recently.
As individuals, we've been seduced by a couple of hundred years of almost free water available at the turn of a tap. This pattern has been repeated through much of the industrialized world. Throughout our world, we're faced with falling dam levels, depleted aquifers, and rising consumption. Whatever the outcome of the debate about climate change, simple population growth in almost every region is sufficient to create a continuing upward pressure on water demand. We're considering new dams, desalination plants and more, to deal with our water supply shortfall.
There are three obvious areas where we can act effectively as
- cut our water use
- catch and use as much rainwater as possible on our block
- re-use as much water as possible before it leaves our block.
Reducing Water Use.
There are a whole lot of habits that can be changed, like running the water while brushing our teeth or peeling the potatoes, or our quaint attachment to lawns best suited to the English climate. The average family even wastes something like 20,000 litres (4,500 gal.) of water a year while waiting for the hot tap to produce hot water! In addition to our ability to reduce water use by changing habits, there are many products that can be installed that can make a dramatic difference to water consumption...
- tap washer replacement valves and aerator taps can dramatically
lower water use
- good low-flow showerheads can save the average family over 40,000 litres (9,000 gal.) a year
- installing new dual-flush toilets can slash water use by tens of thousands of litres a year
- hot water recirculators can make dramatic savings
Catching And Using Rainwater On Our Block.
An average home with a total roof area of 160m2 (1720 sq. ft.) has the potential to collect around 80,000 litres (18,000 gal.) a year if the annual rainfall is around 500mm (20"). That's water than can go on the garden, flush toilets, run washing machines, or even supply a whole house. Every case is different, but there's almost no home that can't make a big dent in it's water usage by installing water tanks. Happily, many government and municipal bodies now provide rebates to assist homeowners install tanks. In a pioneering deal with a local land developer, our company is supplying over 1,000 compact water tanks to homes in their developments that flush the toilets with rainwater, not drinking water. An average family could see 20,000 litres (4,500 gal.) a year come off their water bill. There is a lot we can do to catch and use rainwater.
Re-Using Greywater On Our Block.
This is the big one. It's normally allowed that 150-200 litres (35-45 gal.) of wastewater per person per day leaves our homes. That's 600-800 litres a day for a four-member family, or 219-292,000 litres (50-65,000 gal.) a year! Something around 25% of that is 'black water'. The majority of black water comes from the toilet, and obviously shoudn't be used. The balance of the water we don't want to reuse comes from the kitchen. Because of the fats and organic material that goes down the kitchen sink, it's wise to exclude kitchen water from our calculations. That still leaves a huge volume of usable water leaving our blocks, around 150-220,000 litres (40-50,000 gal.) a year.
Until recently, there has been no convenient, affordable way of reusing grey water on our gardens. Sure, you could always run a hose from the washing machine, or have a bucket in the shower with you to catch some of that water. You could buy a diverter valve for a few tens of dollars. For those with money to burn, you could spend thousands of dollars on anything from amateurish inventions, to a domestic aerated watewater treatment system. We had choices that were convenient, but not affordable, or affordable choices that weren't convenient. As a businessman of many years experience, I knew that the market was there, just waiting for the right product at an affordable price. A few months ago, we found it.
Newly developed products on the market mean that the average household can now do most of its garden watering with a reasonably-priced grey water reuse system. For the Australian market, we are shipping a compact system called the eco-Care Grey Water Diverter System. The eco-Care has a pump that automatically sends grey water to the garden as it is produced. It also has a timer that automatically engages every 24 hours, which ensures that the grey water leaves the system before it has a chance to turn into black water. The price is A$769- equivalent to around US$600 at today's exchange rate. That's definitely affordable for the mass market, and customer interest and sales have been excellent.
A few words of caution. Grey water systems are a 'grey area'. There are a number of issues to be considered if we want a grey water system to give the best results.
- attitude of local authorities. These bodies are responsible
for plumbing standards, and health matters. Some are progressive, some are firmly
stuck in the past.
- health issues. Ideally, grey water should be reticulated underground to avoid human contact, and not come in contact with any vegetables or fruit.
- filtration issues. Water from the laundry contains lint. Water from the bathroom contains hair. Both can block up distribution pipes with small holes.
- chemistry issues. The soaps and detergents we use produce grey water that is alkaline. The degree of alkalinity varies greatly from product to product. Chose products with low sodium and phosphorus levels. Why? Because different plants prefer different acid-alkaline (pH) balances. Putting highly alkaline water on acid-loving plants iwon't get the result you want.
While keeping the issues of the last paragraph in mind, grey water reuse offers a wonderful opportunity for us to maintain the sort of gardens we want, without wasting a single drop of precious drinking water.
Enviro-Friendly Products is just one of many innovative and responsible businesses that can help customers dramatically reduce their water needs. While governments are doing some good things, and could do more, it's now up to us as individuals. If we continue 'business as usual', then we must get used to building (and paying for) new dams and infrastructure. Watch those taxes rise. The most responsible course is to change the way we act, and our the way our homes operate, to reduce our need for water from outside our block. If we come up with the wrong answers, including doing nothing, our children will be paying those dam bills forever!
John Payne is the Founder of Enviro-Friendly Products. He was previously General Manager of a biological wastewater treatment company, and worked at Tidbinbilla Nature Reserve in Canberra, Australia. John has successfully operated many businesses in a 40-year career, and has a life-long interest in science and nature.
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