Tag Archive | "grey water reuse"

Cape Town Drought Cycle. Should Water Tanks be Mandatory?


Over the six past decades, there has been a drought cycle every six to seven years. The last time Cape Town was in adrought was 2004. I have watched this in Cape Town since 1965 when I can first remember the newspapers reporting the dam levels every day, and this has been the case to a greater or lesser extent for the past forty years.

We have always been able to augment further supply by building an additional dam, but not so anymore.  There is not another single place or any more river water that can possibly be found anywhere in the Western Cape for augmenting supply. The Western Cape is simply dammed out of water.  The rest of the country is in no better condition, so we cannot go looking elsewhere to steal this precious resource.

Two ways of augmenting supply to Cape Town have recently been mooted by the minister of DWA (Department of Water Affairs) Buyelwa Sonjica, viz. the desalination of sea water and pumping water out of the Table Mountain aquifer. Simply put, both of these augmentation systems are not sustainable, and should not and must not be pursued. The former is too energy hungry, and the latter means pumping fossil water from the TM aquifer. Clearly these are not options for a way of finding water for Cape Town.

What is studiously being ignored by Minister Sonjica is our ability to use less water, as well as ways to augment our own supply. Minister Sonjica will not be found encouraging citizens to harvest water; mainly because this would not mean any revenue for her department.

However for this to work, we need a few things to fall into place, which things will happen sooner than later.  These are:

  • The inability of our city council to process sewerage.  This really is the case already with Cape Town City Council only able to process 65% of the effluent running to their sewerage treatment works. The rest of the semi and untreated sewerage runs into rivers etc.
  • The inability of the Department of Water Affairs (the owners of the water in our dams) to meet the increasing demand for water for Cape Town from the rivers in the Western Cape.
  • The inability of the City Council to make our drinking water potable.  In this regard, there are a burgeoning number of municipalities around South Africa who admit that they cannot clean the water in the pipelines to a drinkable standard.  Among other reasons for Cape Town is the growing number of informal settlements in our catchment areas. One only has to look at Hout Bay and the condition of the Disa River – the deadly condition of this water kills every living thing in the river and estuary.  The faecal coli (EC) numbers are 9 billion per 100 millilitres of water.  Unacceptable standards are any number higher than 350 per 100 ml.
  • Realization by Cape Town City that there is simply not enough money budgeted in the near and distant future for sewage treatment.  We need 6 billion Rand right now to upgrade existing and build new sewage treatment works.  There is not more than 300 million (5% of the need) budgeted over the long term budget for the City to use for this purpose.
  • Similarly realization that based on simple arithmetic how much water we will need by 2012.
  • Drought. There is conclusive evidence that the Western Cape is being adversely affected by global warming.  The effect of this can be seen clearly today.  Until thirty years ago the character of winter was that it rained for weeks at a time, cleared up for a day or two, and rained for more weeks.  The rain patterns now see us getting one, two or three days of rain followed by a week or two of warm sunshine.  This means that every time it rains, the first ten or even twenty millimetres of rain are needed just to saturate the soil before any run off occurs.  The total number of millimetres of rain may very well be the same but the way it falls makes an enormous difference.  We simply get less run off these days.

What are we able to do about it?

We can augment our own supply.  We should harvest rainwater for using during the rainy season.

The system for this is the Water Rhapsody Grand Opus, which starts with the Water Rhapsody Rain Runner to harvest water from the whole of a roof.  The harvested rainwater is delivered by an unobtrusive underground pipeline around the building, called a ring main, to water tanks (of which there are a large number of different sizes available). Each Rain Runner from each downpipe tees into the ring main.

Rainwater tanks fill very quickly, but an overflowing rainwater tank is not very romantic, so Water Rhapsody plan cleverly to balance the inflow, volume stored and the amount required in the household.

Stored rainwater is then pumped to the whole household. In practice, the stored rainwater is able to sustain the number of people in an average home / business without any municipal feed for an entire rainfall season, and of course in Cape Town, this is in the winter season.

Capetonians use on average 240 litres per person per day, but by using the WWF award winning Water Rhapsody Systems of Conservation you get to use less water without changing your lifestyle. You will with these systems effectively reduce your daily water use from 240 litres to – at worst 120 litres per day. If you do this, stored rainwater will go much further, getting most householders to be completely “off the grid”. This is certainly true for the rain season, and most of the dry season too.  Getting “off the grid” is something we all aspire to, and if we can use all the systems as made and installed by Water Rhapsody, one gets as close to this magic point as is possible.

What we would have done in effect for DWEA and the Municipality without them appreciating us one bit, is to increase the stored water in the dams by a volume of water that is difficult to imagine. It is not just the stored water in one single filling that increases the volume in total, but the yield (which is the number of times the water tanks may be filled and drawn down), and then of course filled again. Should everyone through their own initiative install such a system to harvest, store, and use rainwater, this will make a total annual difference of more than 200 million kilolitres.

This is an amount that I am unable to imagine so for yours and my benefit I have created some analogies:

The volume of the total yield from all the water tanks (total number of times they are filled and drawn down) is the equivalent of more water than the total volume of the second biggest supply dam to Cape Town.  The biggest supply dam to Cape Town is Theewaterskloof near Villiersdorp which holds when full 480 million kilolitres, but not all that water is available for us to use.

Another analogy (bearing in mind the fact that the average use of water in Cape Town per household is 28 kilolitres per month), is saving a kilolitre or tonne of water per household per day.  Put this water into road water tankers and park them nose to tail, and these trucks would stretch from Cape Town to Johannesburg.  Over a whole season, these tankers would stretch around the world (at the equator nose to tail) ten times!

Yet another analogy is to imagine an Olympic sized swimming pool full of water.  The amount of water saved would fill 1350 of these pools per day.

Emergency supply. Yet another of the advantages of having rainwater tanks is that you create an emergency supply against future water outages.  Water outages are the very next way that our municipality will use to get us to use less water.  By having Water Rhapsody to install water tanks to harvest rainwater, for your benefit they will install an emergency supply fed from the municipality, which guarantees the householder of a continuous supply in spite of outages.

Water Rhapsody will provide something for all seasons.

Posted in Grey Water, Rainwater harvesting, water tanksComments Off

Fog Project boosts water supply


A climatologist from the University of South Africa (Unisa) has helped develop a low cost, eco-friendly system to harvest moisture from abundant mountain fog in a water-scarce region of the Eastern Cape, and communities there are already benefiting from it.

The project was successfully launched in Cabazane Village, in the rural Mount Ayliff area in the north of the province, in mid-March 2010 during the annual National Water Week.

The area, which falls in the picturesque Alfred Nzo district municipality, is bordered to the north by the mountain kingdom of Lesotho and much of the terrain is steep and remote, with very cold winters and mild summers. Fog is a frequent visitor and a ready source of clean water.

Professor Jana Olivier of Unisa’s School of Agriculture and Environmental Sciences has spent the past 20 years specialising in the properties and hazards associated with fog, especially for vehicles.

She later started delving into the technique of fog harvesting. “We got funding from the Water Research Commission, and we designed the fog water system,” she said.

Olivier teamed up with Professors Johan van Heerden, Hannes Rautenbach and Tinus Truter – all of Pretoria University – in the development of the system.

Unisa is involved in ongoing research into water harvesting from fog, especially for isolated rural communities, where water is scarce and villagers often have to walk vast distances to fetch a few litres at a time.

However, the system is only practical where fog occurs for at least 40 days a year, and for a period of several hours at a time.

The project has also been rolled out in other dry areas of South Africa, including Venda, Limpopo, and the West Coast, but Mount Ayliff’s persistent fog yields the best results, producing hundreds of litres of water a day.

“The West Coast and the mountainous areas – stretching from the Soutpansberg in the north, along the Drakensberg in the east to the Cape Mountains in the south – have the highest fog harvesting potential,” said Olivier.

Mount Ayliff is located in the Umzimvubu local municipality, one of two municipalities within Alfred Nzo – the other is Umzimkhulu. Umzimvubu’s population is just 198 550, of which only 4% live in towns – the rest live in rural areas.

Safe drinking water is a continual problem as the area lacks essential infrastructure, including water on tap. Villagers are often forced to dip into natural springs, running the risk of picking up water-borne disease.

“We have a challenge … because about 40% of our community here does not have basic water,” said Alfred Nzo mayor Gcinikhaya Mpumza.

However, the villagers’ lives have changed with the installation of the water-harvesting system and its inexhaustible supply. No electricity is needed to power the scheme, which makes it eco-friendly and low-cost, and suitable for areas with no power infrastructure.

Because the technology is simple, the equipment does not need special maintenance. The system consists of a double layer of 30% shade cloth nets stretched between steel cables supported by posts, with a gutter beneath each screen to catch the run-off. All components are readily available in the area.

The Cabazane set-up involves around 700 square metres of netting, said Olivier, with each square metre of shade cloth yielding up to five litres of water a day – depending on the weather.

Water droplets in the fog are trapped on the nets. They get bigger and heavier as the fog rolls along, and eventually run down into the gutter and from there through a filter into storage tanks. The system works best when the wind is blowing, because the fog moves over the nets more rapidly.

The system is installed up on the mountain slope, where nothing more than gravity is needed to get the drops flowing into the tanks. Reports say that about 30 homes in Cabazane Village have already benefited from the project.

The quality of water is described as “very high”, falling within the World Health Organisation’s standards for potable water. “The water is incredibly pure because it comes from the clouds,” said Olivier.

Innovative schemes like the simple and cost-effective fog harvester are well-suited to South Africa, as it’s one of the driest countries in the world, with annual rainfall well below the global average.

Source: MediaClubSouthAfrica.com


Posted in Water ConservationComments Off

S.Africa looks to sea to meet growing water demand


CAPE TOWN (Reuters) – South Africa will increasingly use desalinated seawater to meet growing demand for drinking water in coastal towns facing the worst drought in 150 years, the country’s water minister said on Thursday.

South Africa is a water-scarce country with an average rainfall of 450 millimetres — compared to a world average of 860 mm — and conditions are expected to worsen as a result of global climate warming.

“South Africa has a boundary consisting of approximately 3,000 kilometres of sea water, and this water is presently unusable because of its high salt content,” Water Affairs Minister Buyelwa Sonjica said in her budget vote speech on Thursday.

“We therefore made a decision to press ahead with unconventional water treatment, in this case desalination, largely because of the unavailability of river water due to drought,” she said.

Popular tourist coastal towns Plettenberg Bay, Knysna, George and Mossel Bay are facing severe water shortages due to prolonged drought in the southern Cape region.

These towns have turned to purifying seawater, as well as treating so-called grey water — waste water generated from domestic activities like laundry and bathing — to help meet their drinking needs.

Cape Town is also eyeing the option of desalinating water.

“Desalination has become the preferred purification option in terms of both the cost benefit and the flexibility of application,” Sonjica said.

However, she said the government needed to exercise caution in extending its desalination programme because of possible negative effects to the environment.

“There is ample scientific evidence that the impact of the effluents from the desalination plants on the seawater environment increase the seawater temperature, salinity, water current and turbidity,” said Sonjica.

Desalination is big business in the desert conditions of some Middle East countries, where it is a major supplier of clean drinking water to economic hubs such as Dubai.

Posted in Water ConservationComments Off

Rainwater Harvesting

Rainwater harvesting using water tanks are becoming urban lifestyle trends, saving you reliance on municipal water. Water Rhapsody can provide rain harvesting solutions as simple as a water tank and a filter, to our full blown Rainwater harvesting system that also pumps rain water back into the home from a water tank, and only uses municipal water when the water tanks are empty.

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Against a global rainfall average of 870mm per year, South Africa receives a pitiful 450mm, making it the world's 30th driest country. Water Rhapsody, with 16 years experience in water conservation, is number 1 in South Africa in Grey water recycling systems and Rainwater harvesting systems.Get a quote for your water tanks and water conservation systems now.

Rainwater Harvesting

It is now viable to harvest rainwater for your whole household. This includes rainwater harvesting, storing in a water tank and pumping rainwater for bathing, showering, toilet flushing, pool, laundry and irrigation. Rainwater harvesting together with other Water Rhapsody products can save up to 90% of your municipal water bill. Get a quote for your water tanks, rainwater harvesting systems and other water conservation systems now.

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A bath uses 120 litres and a shower 80 litres of water. When used, that water is called grey water. You pay for it, and then it all goes down the drain. Water Rhapsody Grey Water System uses this grey water to immediately irrigate your garden, saving you a substantial portion of your water bill. Get a quote for your grey water system, water tanks, rainwater harvesting systems and other water conservation systems.

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