Photo courtesy of Thames Water - mains replacement in London
Drivers for investment in AMP6 (2015-2020) is the
theme of the blog this week.
The Water Framework Directive is driving massive investment
as a better understanding of each water basin develops. Nutrient input
especially from phosphates is proving a bigger problem than anticipated.
Already many sewage discharges have a 1mg/l consent especially in slow moving
rivers. This can be achieved relatively easily by using a tertiary treatment
process usually involving chemical dosing (typically ferric chloride) to precipitate
out the phosphate. However in some water courses the Environment Agency is
suggesting discharge consents may need to be an order of magnitude lower
0.1mg/l. This poses a significant technical challenge – several processes are
currently being trialled usually involving a combination of enhanced tertiary
filtration and chemical dosing but as yet no clear winner has emerged.
Despite the recent extremely wet weather concerns over water
leakage has not eased. The issue is the rising population and changes in
lifestyle that is increasing water demand. This is despite the moves by water
companies in the particularly water stressed South East regions to install
water metering for everyone. Several water companies are proposing huge new
reservoirs (Bristol Water for example at Cheddar). The Environment Agency
recognises that winning public support is difficult when water losses are still
averaging over 24% across the network. Virtually unchanged over the last 10
years.
Some new technologies are emerging to detect or manage water
losses especially some sophisticated software systems to improve the monitoring
of the distribution network. A few countries have got leakage down to about 5%.
This has been achieved through a combination of investment in new distribution
mains, extensive metering through the distribution system and tight control of
water pressure to minimise the stress on pipes and leakage if a pipe does
break.
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