Page 259 - Membranes for Industrial Wastewater Recovery and Re-Use

228 Membranes for Industrial Wastewater Recovery and Re-use

5.1 Flag Fen high-purity water production plant (UK)

5.7.7 Background
To many the UK is perceived as a water-rich country but the actual situation is
geospecific with annual rainfall ranging from up to 1600 mm in the north and
west to as low as 550 mm in the south and east. Similar amounts and temporal
distributions of rainfall are found in countries such as Israel where water is
viewed as a commodity and recycling is commonplace. Since the 1990s
legislation has required huge investment in coastal sites to improve effluent
quality prior to discharge. Unlike inland water discharges, coastal waters are a
lost commodity which offers the potential for reuse without downstream impacts
on the water demand balance of the inland areas. Specifically, with further
treatment the coastal discharges could prove an excellent source of industrial
water intake. Not only does this provide a reliable source of water to the
industrial client but alleviates a commensurate amount of potable water stress
on the public supply.
Anglian Water Group (AWG) is the water and sewerage operator for a region
of the UK in the east of the country and suffers from some of the lowest annual
rainfall in the country. Increasing population growth within the AWG supply
region has led the company to look at the strategic benefits of the use of coastal
discharges. A survey of potential industrial partners was conducted based on the
following criteria:
0 Proximity to a sewage works
0 Proximity to a coastal discharge
0 Non-food industry
0 Need for significant amounts of ultrapure water
0 Long asset life ( > 10 years)

One of the ideal candidates was identified as the power station in Peterborough
owned by Texas Utilities (TXU). The station is located adjacent to Flag Fen
sewage works which treats the majority of the flow from Peterborough.
Negotiations between TXU and Alpheus Environmental (a wholly owned
subsidiary of AWG) determined the contractual and expected product water
quality from the advanced treatment works that would supply the power station
(Table 5.1). The plant was built in the spring of 2000 and started operating in the
summer.

5.7.2 Description of plant
The initial process selection was controlled by the requirement to produce high
purity water with a conductivity of 70 pS cm-l which restricted the final stage to
a reverse osmosis plant. The real challenge of the project concerned the
pretreatment to the RO plant which had to provide a robust feed water from a