FILTRATION AND SEPARATION
Thames Water has installed a filtration system for washwater at the UK’s largest sewage treatment works. John Dow, the MD of Bollfilter UK explains the choice
T
hames Water’s Sewage Treatment Works (STW) in Beckton, East London is the biggest in the UK and one of the largest
in Europe, serving 3.4 million people throughout London. The works, which is undergoing a major expansion programme, features the latest sludge treatment technology, including a sludge powered generator for energy efficient waste disposal. The sewage treatment process features eight
large screens that can operate continually to remove screenings from the sewage. Following primary and secondary treatment, washwater is fed into the screens via a series of nozzles to wash the sludge off and clean the screens and brushes . In order to prevent the washwater nozzles
from blocking and disrupting the screenings separation process, a Bollfilter automatic filtration system has been installed in the Beckton screen house. The system which comprises two Boll 6.19
automatic self-cleaning filters and CCD pumps is mounted on one skid for ease of installation. The 6.19 filters, which operate under low pressure conditions, are fitted to the washwater inlet feed prior to the pumps, with the added benefit of protecting these from possible particulate damage. A small amount of the pressurised
Beckton’s sludge powered generator provides power to the site and feeds excess electricity back into the national grid; two of the Beckton sludge screens
Filter keeps the washwater flowing
washwater is fed back into the filters for efficient cleaning without the need for separate backflush pumps, creating a low energy, space efficient filter/pump solution. The Beckton filter skid is the second
similar installation fitted by Laing O’Rourke for Thames Water.
Kevin Woolley, Laing O’Rourke’s construction manager explains the choice of the Boll 6.19 low pressure system. “We have found Boll filters to be very good. We installed a similar installation at the Thames Water’s Deephams STW, following problems with two previous filter systems. The Boll filters have worked well ever since.”■■■
Watertechnologies. Since March, water purified using ultra-fine filtration has been available by simply turning on the tap. The area that makes up the city of
Luxembourg raises a glass for UF A
drinking water treatment plant in Luxembourg has installed ultrafiltration (UF) modules from Inge
Luxembourg features 71 springs and water sources, though only 38 of them are used to obtain drinking water. The quality of the water acquired from these sources varies depending on how the land that feeds the spring is used. The water supplied to the Birelergronn water
treatment plant comes from a total of 14 sources and is collected and temporarily stored in a reservoir that consists of four separate chambers. This reservoir simultaneously serves as a pump tank for the drinking water pumping station that conveys the water to the Sandweiler water towers. The untreated water in Birelergronn
occasionally exhibits microbiological impurities and elevated levels of turbidity. The city therefore decided to treat the water using a UF system – and they chose Inge Watertechnologies from Greifenberg near Munich to supply the modules. Inge says its membranes are resilient membranes and the sustainably cost-effective operating concepts of the systems they supply. The first stage of the Birelergronn plant features 36 Dizzer 5000 MB modules arranged in two racks, each of which provides a treatment capacity of 1,680m3/d. The idea is to incorporate further water sources in the treatment process at a later point in time. Plans have already been drawn up a further stage which would then feature a total of 44 modules in two filtration lines and an overall capacity of 4,320m3/d. To protect the membranes from abrasive substances, a fine filter with a cut-off of 300µm is installed upstream
28 Water & Wastewater Treatment September 2010
from each block. The remainder of the job is undertaken by Inge Watertechnologies small-pore membranes, which remove bacteria, viruses and suspended solids from the water using purely physical means – without the use of chemicals. The result is ultra-pure water that Luxembourg’s inhabitants can drink with confidence. Bruno Steis, chief executive of Inge
Watertechnologies, said: “We are delighted to have been given this opportunity to equip a drinking water treatment plant in Luxembourg with our ultrafiltration technology. Birelergronn represents a fantastic showcase project in the Benelux region which will attract interest from plenty of other districts in the wider area.“ Viviane Loschetter, the Luxembourg councillor
responsible for environmental affairs said: “The city of Luxembourg makes tremendous efforts to constantly monitor the quality of the water people here drink.”■■■
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