The Portsmouth Society - News
| News | Waterworks Visit | |
| Earlier news | Some of us went on the Environmental Forum's visit to the Portsmouth Water
company's works on Portsdown hill. The occasion for the visit was the opening
of the new £5million filtration plant. Most of Portsmouth's water comes from the springs at Bedhampton. Until recently the treatment for the water consisted of filtration through sand filters with the addition of a small amount of orthophosphoric acid whose function is mainly to eliminate any lead from the water. It also reduces scale, for example in kettles. Some aluminium sulphate is also added to coagulate microscopic particles. The works process over 40 million litres of water a day and supplies 196,000 people. The new plant was necessitated by the contamination of the water by a microorganism, a protozoon called cryptosporidium, originating in the droppings of farm animals, which was not filtered out by the sand filters and could not be eliminated by chlorination. This is a nationwide problem. In the new plant which cost £5 million the water is forced through much finer filters consisting of bundles of straw-like tubes. And these do intercept the offending organisms. The works are full of the latest technological mechanisms. The filters are automatically switched off and changed when they have done their stint and at every stage the quality of the water is monitored. The Portsmouth Water Company is a private company established long before the privatisation that took place under the Thatcher government.. Some of Portsmouth water is extracted from the River Itchen but most of it comes from the springs at Bedhampton from where it is pumped up to the filters and reservoirs near the top Portsdown Hill. There are standby generators to supply the pumps in the event of power failure. The water has already been filtered through the chalk of the South Downs. It is naturally of very high quality. The reservoirs at Farlington hold only about two days' supply. The main reservoir is the South Downs. Only about 2% of this high quality, expensively treated, water is actually drunk by humans. And some people still prefer to buy their drinking water in bottles! RJ |