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Journal nr. 7509/13
Uppsala Vatten, Sverige: Erfaringer med blødgøring
Fra Philip McCleaf
Processingeniør
Uppsala Vatten
16.6. 2010, sendt som mail
Dear Ms. Von Bülow
I have just finished discussing your questions with some of my colleagues and our responses to your
questions can be found below in the text of your original message. However, a little background information
concerning softening here in Uppsala may help clarify the situation.
Central softening has been in operation in Uppsala since approximately October 2007. Previously, Uppsala’s
drinking water had a calcium level of approximately 85-100 mg/l and magnesium 9-16 mg/l. That is a
hardness level of about 14-18 German degrees of hardness (dH). The alkalinity of our water was
approximately 280-330 mg/l as bicarbonate and pH 7,2.
The central softening process we utilize is a fluidized pellet bed reactor process wherein slaked lime is
dosed to the raw water and the pH is increased to pH 9-9,5. At this elevated pH the chemical reaction occurs
wherein soluble calcium is crystallized as calcium carbonate and builds pellets in the fluidized reactor. The
calcium content is about 35 mg/l with bicarbonate alkalinity 110 mg/l and pH 8,3 in the water distributed to
our customers. Thus hardness of our water is reduced to between 7-8 dH without affecting the magnesium
content of the water. Again note that only calcium hardness is removed in our softening process not
magnesium hardness.
Best Regards,
Philip McCleaf
Från: Dorthe von Bülow [mailto:[email protected]]
Skickat: den 16 juni 2010 09:56
Till: McCleaf Philip
Ämne: Vs: Copenhagen Water Department seeks information about softening
Dear Philip McCleaf,
Allow me to remind you of my prior mail to you.
I´d appreciate very much if you could help me with some information on your experiences with softening,
especially issues relating to the customers´ interests and reactions.
Kindest Regards/
Med venlig hilsen
Dorthe von Bülow
Water Supply and Sewage Department
Direkte tlf: 2795 4672
E-mail: [email protected]
Københavns Energi A/S • Ørestads Boulevard 35 • 2300 København S • CVR: 10073022 • tlf. 3395339
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----- Videresendt af Dorthe von Bülow/4530 Salg & Produkt/KBHE den 16-06-2010 09:50 -----
Dorthe von Bülow/4530 Salg & Produkt/KBHE
Salg & Service Vand & Afløb
2795 4672
21-05-2010 12:09
[email protected]
cc
EmneCopenhagen Water Department seeks information about softening
Dear Philip McCleaf,
As I mentioned on the phone we are right now investigating the possibilities and consequences of softening
the Copenhagen drinking water. Our water holds 20 German degrees right now. We deliver water to
Copenhagen city and to 18 other municipalities outside Copenhagen, altogether 54 mio. m3 water yearly to 1
mio. citizens.
We are investigating the technical and environmental issues relating to softening. In addition, we are
interested in possible responses from various categories of consumers and companies.
I am working in Sales and Services Section and have been assigned the task of looking into issues relating
to consumer interests.
I understand that it is fairly recent that softening of drinking water have been introduced in Uppsala.
Hence, I would very much like to know about your experiences in this field, and I would appreciate very
much if you could answer my questions below:
1. What was the reason for implementing softening of drinking water in Uppsala? And what were the
main arguments for doing it? The main reasons for implementing softening in the drinking water
were to reduce hardness deposits in heating systems and household appliances, reduce the amount
2.
3.
4.
5.
6.
7.
8.
of laundry and dishwashing detergents, reduce the amount of copper corrosion in consumers’ piping
systems, and decrease the use of salt-regenerated ion exchange softening equipment by our
customers. The reduction of copper corrosion in turn is aimed at reducing the amount of dissolved
copper in our wastewater and in our wastewater sludge residuals. The ultimate goal is the use of our
wastewater sludge as a soil amendment.
Was an investigation of customers´ interests and reactions undertaken prior to the implementation of
softening? If so, which groups of customers did the study involve? No formal structured investigation
of interests or reactions was made.
Did you foresee any problems or negative responses from the customers? Of what kind? There was
some concern about the possible reduction of magnesium and the possible health benefits provided
by magnesium. However the process that we utilize does not significantly reduce the amount of
magnesium in the drinking water.
Did you encounter any resistance from companies that produce,, install and service decentralized
softening systems? And has it turned out to be a problem afterwards for this type of sector or
business? There were some mixed signals sent to our customers. On one hand we the “water
provider” informed our customers that private/home owner water softening would not be needed
after central softening was implemented. While purveyors of home water softening devices
advertised that private/home water softening would still be required. Approximately 50-100 calls
were received by us from our customers asking for a clarification.
And likewise, has it caused problems for laundries, restaurants, hotels etc. who have invested in
their own decentralized systems? Central water softening has not caused problems for these
customers, but since they had become acclimated to almost completely softened water from their
decentralized systems, many have chosen to continue operating their own decentralized softening
systems. Especially those utilizing hot water above 90 C for example industrial dishwashing. One
could say they had too high expectations of central water softening or did not understand the degree
of softening afforded by their own decentralized systems.
Have you experienced any positive reactions from customers regarding less use of soap, washing
powder and chemicals for cleaning or prolongation of service life of household appliances (wasking
machine, dish washer, coffee machine etc. We have experienced positive reaction about the
decreased need for cleaning of calcium carbonate scale from shower, bathtubs and sinks.
Have you experienced any positive developments among children regarding atopic eczema? We are
not aware of any problems or developments.
And finally, did you launch any kind of information campaigns among customers regarding the
implementation of softening? Yes, we had an information campaign which began around December
2003 a copy of which is attached. From 2003 until operation of the plant in 2007 we published
information in the local newspapers and in our newsletter that is sent out to all our customers.
I would appreciate very much if you could send me the contact information you mentioned from
Holland/Amsterdam. Mr. Bas Brouwer, RWB Water Services, PO Box 223, 7600 AE Almelo, tel +31 546 545
025
Best Regards
Dorthe von Bülow
Water and Sewage Department,
Copenhagen Energy
Dear Mr. Philip McCleaf,
Sendt som mail d. 21. 6. 2010:
Thank you very much for your dedailed replies to our questions, it is most helpful in our investigations
regarding softening. We understand that you published information about softening to the customers from
2003 to 2007, a very useful information to us.
In your reply you also mention an information campaign from December 2003. We would very much like to
see a copy of that campaign, if possible.
Best Regards
Dorthe von Bülow
Copenhagen Energy