THAMES WATER EXPERIENCE
TREATMENT ON ITS HEAD
OF
MICROFLOTATION:
TURNING
PRIMARY
Microflotation offers a promising alternative to conventional primary treatment processes,
using tiny bubbles to float solids to the surface instead of letting them settle to the bottom of
the tank. By dissolving air in water under pressure in the enviplan® AQUATECTOR® unit and
then releasing that pressure through a carefully designed nozzle, microbubbles of 30-50
microns in diameter are formed. These bubbles, which form a cloud of white water in the
primary treatment tank, attach to solid particles including fat, oils and grease (FOG) and force
them upwards where they can be scraped from the surface. The process is more efficient at
removing solids than traditional settlement methods, with the Enviplan technology achieving
up to 95% removal of solids and, when combined with chemical dosing, up to 65% phosphorus
removal.
The impact of this increased solids removal in the primary treatment stage is twofold. The
lower solids and nutrients concentration entering the secondary treatment process leads to
energy savings from reduced aeration requirements. Additionally, the increase in the volume
of primary sludge compared to secondary sludge leads to better quality feed for anaerobic
digesters. As the retention time in this process is much shorter than in conventional PSTs,
leading to a smaller footprint, enviplan®’s Microfloat technology could be the perfect solution
for sites experiencing rapid growth. What’s more, the process can be easily retrofitted into an
existing tank allowing water companies to avoid building costly extensions to STWs.
Thames Water’s Wastewater Innovation team is currently trialling the technology at pilot scale
at a number of large sites, which could benefit from a retrofit of the technology. The pilot plant
processes up to 10m3/h of screened crude sewage, and allows the effects of chemical dosing
and co-settlement of secondary sludge in the primary tank to be studied under the various
operating conditions relevant for each site.
Roland Damann, managing director of Enviplan, said:
“We are very proud to serve Thames Water in this ambitious project after having
successfully introduced AQUATECTOR® Microfloat® technology for this application
in Austria, Switzerland and Germany with outstanding results. If STW capacity needs
to be increased, introduction of microflotation has proven to be an appropriate
solution, as it will require smaller aeration tanks and lower overall power
consumption. Additionally the full benefit of microflotation is obvious if sludge
treatment and the increased potential for energy generation are taken into
consideration. The energy saving and generation benefits are a likely driver for
implementation of microflotation as a primary wastewater treatment stage.”
Rebecca Sindall, a senior research scientist at Thames Water, said:
“The microflotation pilot plant has generated a lot of interest across Thames Water.
The initial results from the trial suggest that this technology could be a real game-
changer for the wastewater industry. The plant is easy and economical to operate and
the ability to remove such a high percentage of solids, including FOG, in the primary
treatment stage has such important benefits for downstream processes, both in the
wastewater treatment and in the sludge stream.”
The results of Thames Water’s pilot scale trials of the Enviplan microflotation technology will
be presented at Aqua Enviro’s 9th European Waste Water Management conference at
Manchester Town Hall on 12-13th October 2015. www.ewwmconference.com/
NOTES FOR EDITORS:
Aqua Enviro is a leading, specialist environmental consultancy, conference organiser and training provider in the
water, wastewater, bio-resources and organic waste sectors. With no links to any products or companies we are
able to give you truly impartial advice.
With more than 25 years of success in the field of water and wastewater treatment, enviplan® is one of the most
experienced companies for industrial and municipal water and wastewater treatment, particularly in the field of
microflotation technology. The system has more than 280 industrial and municipal reference plants and projects in
Germany and globally. In 2012, enviplan® received the German Innovation Award. For more information visit
www.enviplan.de. Alternatively call Roland Damann at enviplan® on +491707629925 or damann@enviplan.de
Thames Water is the UK’s largest water and wastewater treatment company with a service area that stretches
from Gloucestershire and Wiltshire in the west, through London and the Thames Valley to the western edges of
Essex and Kent in the east. It recycles safely back to the environment the wastewater of 15 million people; that’s
4,300m litres of sewage every day. Its tap water is in the top 10 of major suppliers in the UK. It supplies nine million
customers with 2,600m litres every day and carries out half a million quality tests every year.
Thames Water is also the biggest non-commercial producer of electricity inside the M25. It burns methane derived
from sewage to create heat from which to power its own renewable electricity and power its works. Along with solar
and wind self-generation, this saves the company on average £15m a year in grid energy bills.