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WETLANDS COULD HELP COMBAT WATERBORNE DISEASE
Worldwide, some 50 000 people die daily due to waterborne and water related diseases, while 80% of all diseases worldwide are attributable to drinking water quality, says David Lindley, national coordinator of the Mondi Wetlands Project.
"People don't realise how dangerous dirty water is," he says. "For example, Environmentek's Cape Water Programme involved 12 rural communities in the Western Cape and found that 33% of people did not disinfect their drinking water, even though almost two thirds of samples failed the SABS Drinking Water Maximum Allowable Limits."
At least 650 South Africans die of diarrhoea every day. The Water Research Commission says that short term direct costs, such as hospitalisation and treatment of diarrhoea patients are around R5 billion a year. Total annual costs are estimated at R15 billion.
These costs can only get higher if we consider South Africa's rising population, lack of services and falling health budget. For example, the rivers around Gauteng are rapidly deteriorating and the water has become a microbiological cesspool. Samples taken by Urban Green File magazine at Bruma Lake, Gillooly's Farm, Alexandra and Northern Wastewater Treatment Works showed faecal coliforms per 100ml as 450 000, 450 000, 3 million and 30 000 respectively. (The target is 130 maximum).
E. coli per 100 ml were 60 000, 25 000, 3 million and 30 000 respectively. (The ideal is a maximum of 130).
The Star newspaper recently reported that bacterial contamination of the Klip River, between Alberton and Meyerton, was unacceptably high and could pose a health risk. Sewage works have been rapped over the knuckles by Rand Water after alarmingly high levels of bacteria were found in the water. Many sewage works said they had 'run out of chlorine' because bills had not been paid. The Klip River is used by towns such as Parys for drinking water.
Northern Sewage Works' discharge water - after processing - has had E. coli counts as high as 69 000 per 100 ml. Yet water is considered suitable for swimming with less than 125
E. coli per 100 ml. At one stage, eight sewage works in Gauteng were allowing raw waste into rivers. Sewage can carry cholera, typhoid, hepatitis and dysentery, all of which start with acute
diarrhoea.
A few Johannesburg children have even contracted dangerous shigella dysentery. Fishermen, canoeists and swimmers often seek recreation in waterways that posed a dire threat to health.
"Contaminated rivers do not only affect people who wash or play in them," warns David Lindley. "Diseases which start with swimmers can quickly spread through a community." When contaminated water is sprayed on crops, food becomes unsafe. People who drink river water work in the homes of people who drink tap water. The bacteria can be spread. There is a cycle and everyone is at risk, no matter who they are.
Wetlands to the rescue
Luckily wetlands provide a free service in purifying water, a service we would do well to utilise more effectively if we are to contain the rapid deterioration of water, David Lindley points out. If we lost the services of wetlands, we would have to replace them with artificial wetlands and extra water treatment plants at great cost.
In America, the important role that wetlands play in improving water quality is recognised by protecting wetlands in the Clean Water Act. In both USA and Europe, extensive wetland areas are being restored and conserved as part of broad integrated plans to maintain good catchment quality.
That natural wetlands improve water quality should be taken into consideration by all private and government agencies concerned with land-use management and planning, says South African wetland expert George Begg. Every effort should be made to preserve the few wetlands remaining in many agricultural and urban areas. Wetlands behave as nitrogen and phosphorous 'traps'.
Removal efficiencies of up to 90% of nitrogen have been reported for some wetlands. Submerged soils, high in organic matter are phosphorous 'sinks'. Various studies have been made in wetland ecosystems of the changes in concentrations of other dissolved compounds in water such as sodium, chloride, calcium, magnesium and potassium. Their fate is less well understood. There is some evidence that wetlands remove heavy metals - from 15% to 32%. It is important to realise that wetlands store certain components that they remove because the disturbance of wetlands leads to their release back into the system. Water-borne pathogens are not stored but destroyed by wetlands. An efficiency of 86% coliform bacteria was achieved in the USA.
"Conserving and improving what wetlands we have left, as well as restoring defunct wetlands, are urgent priorities if we are to address South Africa's deteriorating water quality," says David Lindley.
At present in Gauteng, the water drawn by Rand Water is from the Vaal Dam and not the barrage and this water is in good condition so purification costs are low (they would increase if there were more bacteria in the water) say Marc de Fontaine, Catchment Coordinator for the Vaal Barrage at Rand Water.
There are however problems with the Rietspruit, Blesbokspruit and Klip Rivers but these drain into the Vaal Barrage below the dam. Purified drinking water is safe because it is disinfected but danger lurks for people using river water - either for drinking, washing or swimming, he warns.
The Klip River already has many wetlands on it which are helping to keep the water clean, Marc de Fontaine comments. Water quality would be a lot worse if the wetlands were absent. However, there is a limit to how much pollution wetlands can remove from water. "Artificial wetlands would be a good idea but they would not function straight away," he says. "People using river water need to be educated."
Because faecal contamination is a diffuse source it is difficult to point fingers but some of the culprits include informal settlements without sanitation and municipal water treatment works that do not purify water properly.
Hope in artificial wetlands
While conserving and restoring natural wetlands is Mondi Wetlands Project's main function (and also because nature does a more efficient job than mankind), artificial wetlands have their place as well in water purification," says David Lindley.
Constructed wetlands are designed, built and operated to emulate the natural functions of wetlands. Constructed wetlands have advantages over other means of treating waste water because they require little energy, chemical input or maintenance. The constructed wetland at Mount Grace Hotel, for example, is both functional and aesthetically pleasing. Its operating costs are also low. Wetlands are being actively investigated on a number of South African mines to provide a self-maintaining long term (including after mine closure) solution to the treatment of acid drainages and leachates. However, the technology is new and still being perfected.
Nursery owners in America and Europe were facing punitive measures if they did not reduce contamination of their water supplies and many turned to artificial wetlands to purify water so they could avoid using chlorine and other harmful chemicals. A local nursery owner is now also using researchers at Potchefstroom University to help him construct an artificial wetland.
The CSIR Water Technology branch as "Wetland Ecological Technologies (WET)", explores a range of artificial wetland installations. Wetlands can be used by rural schools, police stations, game lodges, caravan parks or in communities without sewerage systems. Standard wetland designs are also available for smaller installations, from 25 to 100 people. A DIY installation is also available as modular design kits, in four-person modules which can handle the waste of up to 12 people. There are currently more than 40 artificial wetland sewage systems operating in South Africa including 12 in the Kruger National Park, other game reserves and in small communities (for information, contact CSIR on (012) 841 3580).
For further information on the Mondi Wetlands Project, contact David Lindley on 083 - 222 9155 or e-mail :
lindley@wetland.org.za or visit
their web-site at www.wetland.org.za
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