We can’t get away from the fact that man, in common with other mammals, produces vast quantities of bodily waste. Left lying around and untreated this waste will spread diseases such as diarrhoea and cholera, some of which can prove fatal. In fact we only have to look at a single incident to see how fatal water borne disease can be.
Since it was struck by an earthquake in 2010, Haiti has seen the largest outbreak of cholera in recent years. More than 7,500 people in Haiti have died from the disease and hundreds of new cases are still being reported every week. Until 2010, Haiti had been cholera free for hundreds of years. Recently a report by a US cholera specialist has identified the Haitian outbreak as having the same genome as that seen in Nepal and it is now believed that inadequate sewage disposal facilities in the camp of a group of Nepalese soldiers, brought in to help with post-earthquake construction, may have led to the outbreak.
Whilst this is an extreme case, it does underline the care which is required when treating and disposing of human waste. Water authorities have a duty of care to ensure that treatment is as safe and effective as possible and within the EU there are strict guidelines in respect of water quality and effluent disposal. Such was the challenge which met Scottish Water when they were faced with replacing a treatment plant at Cartland. The old sewage treatment plant which served eighty residents was nearing the end of its natural life and Scottish Water wanted to not only replace it but to open up treatment for a further sixteen properties.
In researching the options available Scottish Water had in mind a low carbon and sustainable waste water solution which would be in harmony with the local environment. At stake was the health of a nearby watercourse, the Brocklinn Burn, into which treated effluent would be pumped. The final solution chosen was a wetland treatment system, designed in conjunction with Wildfowl and Wetlands Trust (Consulting) Ltd. The design not only requires no mains power; the materials used in construction have been chosen to provide a low carbon impact and also make use of recycled products.
With no ongoing power costs, no mechanical plant requiring maintenance and replacement and multi-stage primary settlement minimising the build up of solids the solution for the Cartland Sewage treatment works is environmentally friendly and cost effective. It was therefore a worthy winner of a Green Apple award for Environmental Best Practice.