Plumbing Africa July 2018 | Page 27

HEALTH AND SANITATION 25 Do septic tanks work? South African plumbers have an opportunity to help set world standards; tell us about your experience with the humble septic tank. By Mike Muller The United Nations wants everyone to have safely managed water supplies and sanitation by 2030. That’s going to create a lot of work for everyone in the water sector. But, before that happens, we need to know just what “safely managed” means and how do we measure it? With water supply, it is relatively easy: Does water come out of the taps reliably and is the water safe to drink? In South Africa, we already know the answer to the first question (it has been getting less reliable every year). We used to know the answer to the second question, until Minister Mokonyane stopped publishing the Blue Drop report because it was too embarrassing. Sanitation is more difficult. We can estimate how many blocked sewers spill muck and germs into the roads and how many treatment plants are working (if only the Minister would publish the Green Drop reports!). But there are plenty of people who do not have access to sewerage. That is why the UN’s Joint Monitoring Programme is asking questions about septic tanks. Do they work? And are they safe? This is already a problem in developed countries. In Ireland, there were near riots when, in compliance with EU rules, the authorities started surveying the state of septic tanks in rural areas — and charging people to be inspected. The surveys found that many septic tanks were unsafe, usually because their soakaways were inadequate. The danger is that poorly treated waste could flow onto the surface, spreading germs onto people’s shoes and hands and then into their mouths and food. www.plumbingafrica.co.za So, it is of concern that some companies that sell plastic septic tank units provide detailed installation instructions on how to bury the tanks but give no guidance on what is needed for a good drain field. This can be a real problem on small sites where there isn’t enough room. Drain fields work in two ways: either the liquid evaporates from the soil, or it soaks into the ground. Either way, it needs enough space to do that — the old city regulations used to prohibit septic tanks on stands less than 2 000m 2 . Now, septic tanks can be a real boon in p laces where there are no sewers, as in many of the extensive settlements in the former homelands. People there want — and often can afford — to have a flush toilet, but they won’t get one if they wait for their municipality to install sewerage. So, we should be planning for this and providing guidance on how to build proper systems. The other question is, where is the water for flushing going to come from? Many rural water supplies have been designed to provide 50 litres of water per person daily. As people in Cape Town are discovering, that is not enough if you are going to flush every time you use the toilet. In Cape Town, because of the crisis, household water use is being strictly monitored but in our rural settlements, that is the exception — not the rule. Mike Muller Mike Muller is a visiting adjunct professor at the Wits University School of Governance and a former Commissioner of the National Planning Commission and Director General of Water Affairs. So perhaps the real problem with septic tanks is that they are using a lot of water, which means, very often, that there is not enough to go around. That’s one more thing for the new Minister to think about! What advice would you give him? PA July 2018 Volume 24 I Number 5