Water, Sewage & Effluent May June 2019 - Page 30

The business of safe water Disinfection and the challenge of old infrastructure rears its ugly head. By Mike Muller T products like petrol for foreign exchange. We could get lime locally, but aluminium sulphate and chlorine were imported. Although some people complain about its taste, chlorine is one of the world’s wonder drugs. It has saved more lives than almost all medicines. I discovered that in Beira when we ran out for a couple of weeks and the number of patients at local clinics immediately increased. “Is there something we could do about this?” I asked the UK-based Intermediate Technology Development Group, founded by the famous ‘small is beautiful’ professor Fritz Schumacher. Specifically, could we produce chlorine locally? Being by the sea, we had mountains of salt available (for readers who failed chemistry, salt – or sodium chloride is the raw material for producing caustic-soda with chlorine as a by-product). We had electricity from the hydropower plants on the Buzi river. Was there a chlorine generator for water treatment in poor countries? If not, could we develop a robust piece of equipment to electrolyse a salt solution and produce disinfection- strength sodium hypochlorite? ITDG found a chemical engineer who confirmed that it was indeed possible. he recent cyclone Idai disaster in Mozambique reminded me of another life, when I ran the water supply of Beira. Contrary to media reports, Beira wasn’t the worst affected by the cyclone – that was the dubious privilege of the small town of Buzi on the other side of a rather wide estuary. Beira’s water supply was restored within a few days of the cyclone when the power lines were put back up. But it was always a challenge to keep the city’s water running and safe, not least because important things like chemicals for water treatment competed with Seawater, with its natural supply of sodium chloride, is the raw material capable of producing caustic soda with chlorine as a by-product. 28 Water Sewage & Effluent May/June 2019 www.waterafrica.co.za