2O – Grey water

Supporting article O: Re-use your grey water and become part of the solution


River Pollution and Reuse of Grey Water

Feb 252010

With the installation of a grey water system you will be contributing not only to the current surge in water saving activity in South Africa but also to the cleaning up of our river systems.  It has recently been made public that the state of sewerage works stations in South Africa is dire to say the least.  Only around 6% of the stations active in the country are operating according to national health safety standards.  The result is that untreated or insufficiently treated effluent is finding its way into our rivers at an alarming rate.  Our system allows you to slash the amount of effluent leaving your building by up to 50% thereby ensuring that you are doing your part by not contributing to the very real environmental problem of pollution in our river systems Please read on for an example of how our river systems are being affected by the over burden of our sewerage treatment works.

Pollution levels in the Klein River estuary at Hermanus – which runs through the main beach – are so high they are “off the chart” of what the laboratories are able to measure.
Fish have been washing up dead in the estuary since the start of December and are still dying. The water quality of the Bot River and Onrus River estuaries is also well above the maximum allowed for E coli pollution.

Rob Fryer, manager of the Overstrand Conservation Foundation, said yesterday: “The Klein River estuary is extremely sick and deteriorating. Testing by the Overberg District Municipal health department shows 100 percent of water samples tested over December and January were in excess of the standards.

“The laboratories can test only up to 2 419 counts of E coli per 100ml, and all the samples were at this level, which probably means they are above 2 419,” Fryer said.
The Department of Water Affairs states that the maximum level for safe recreational use of rivers and estuaries is that 80 percent of the water samples must be less than 100 counts of E coli in a 100ml of water, and that 95 percent of the samples must be less than 2 000 counts a 100ml.

Fryer said people were still swimming and boating in the dirty estuary.

Scientists Steve Lamberth from Marine and Coastal Management and Lara van Niekerk from the CSIR had investigated the cause of the fish deaths 10 days ago, and had found they were caused by low oxygen levels in the water. This was the result of a high level of nutrients in the river, which stimulated an algal bloom, or massive growth in algae, which then depleted the oxygen.

Fryer said there were several possible causes for the high level of nutrients in the estuary.

“It could be from the Stanford sewerage works, from seepage from the many old septic tanks along the rivers, run-off from wineries, from the brewery and from farming upstream, but the extent of pollution from each is not known.”

Fryer said if a single sample had shown pollution levels of 2 419, he would not be concerned, but for 100 percent of samples taken over two months to be at the maximum the laboratories could measure showed the severity of the problem.