Re: Ion Technology Dramatically Improves Village’s Water Quality
(WC&P, Nov. 2005)
This article makes for interesting reading, providing as it does, an insight into problems of dealing with waters in various parts of the world. In the U.K. we do not of course have the vastnesses of area hence our main (almost only) problem is that of high bicarbonate hardness which for the most part will be treated by the householder—if at all—rather than at source.
The paper by Mr. Sanchez is somewhat unspecific regarding certain details, however, and I wonder if he and his team could be kind enough to help with some extra information as per the following:
- From the descriptions given would it be correct to assume that the set up comprises in essence sodium form cation exchange softening plus chloride form anion exchange for removal of the species mentioned below the photograph at the top of page 31?
- In preliminary study, were there any problems relating to displacement of radium by the predominant cations towards the exit end of the resin bed once the softeners had attained ‘settled down’ running condition?
- Further to the last point, does leakage occur during the service cycle and if so, which ions? (Possibly a case for COR operation?)
- What criterion is used for breakthrough/service run termination?
- How quantitative is the regeneration/elution, particularly with regard to radium? (This would be relevant to the leakage question above.)
- Are there some specific precautions relating to H and S in view of the concentration effect of the radium on the resin bed in the service cycle? Or in this respect, is the actual absolute level not seriously hazardous? Presumably provision was built in to cope with spillage.
- What arrangements are in place to deal with the regenerant effluent, which presumably contains excessive radium to allow simple disposal to land?
In due course, the U.K. may decide that to plug an energy gap a further program of nuclear fired generating plant will be constructed; when, (to judge by precedent) the handling and decontamination of aquifers will be more than just academic.
My thanks in anticipation for any comments in reply.
G. Allen Segar B Sc M VV M Soc.
Proprietor GARIX Associates
Exclusive Representatives of Resindion (U.K. and Ireland)
Div. of Mitsubishi Chemical Corporation
Response from Romeoville’s Joe Sanchez
Met with our staff and happy to answer your questions (See numeric references to your original, please.) Thank you for your interest in the article and I hope this helps.
1) Our process only uses cation exchange to remove calcium, magnesium and radium.
2) and 3) The ion exchange process with this resin will continue to remove radium beyond the point in which it is exhausted with calcium and magnesium. I believe the resin will even exchange captured calcium for radium. So by monitoring effluent calcium and magnesium levels for breakthrough, operators can have high confidence that 95+ percent radium removal is being achieved up to the point of resin regeneration.
4) It is usually based on computations. The village’s resin has 20000 grain capacity per cubic foot of media. Also as stated above, calcium and magnesium levels can be monitored.
5) This is probably a better question for the ion exchange resin and equipment manufacturer. This is dependant upon the raw water radium levels, calcium levels and magnesium levels. The softeners will treat about 300,000 gallons of water between regenerations. The amount of captured ions for the different contaminants that will be released to waste depends upon the influent levels.
6) It is my understanding that radium is only hazardous to health and safety when ingested. Emissions of radium decay will not penetrate the steel tank in which it is captured. Also, regeneration occurs quite frequently and displaces the radium back to the sanitary stream, which it has always traveled. Here it is diluted pratically back to its raw water levels.
7) See above. Sampling at the wastewater treatment facility has shown that effluent levels of radium are within regulatory limits at the Village of Romeoville.
I was catching up on my reading over the recent holiday period when I came across the paper by James Bolton of IUVA entitled Fundamentals of Ultraviolet Treatmen: Terms and Definitions Do Matter! in WC&P, May 2005. For interest and perhaps the benefit of the readership on the outskirts of this technology, I would like to offer corrections and some comments to the paper.
Firstly, on page 26, top of third column, the paper assigns the title of Beer-Lambert law to Transmittance etc. This is incorrect. The correct title of the law is the Bouger-Lambert law. The law was discovered by Bouger in 1729 and refined by Lambert in 1760 (ref: Ultraviolet Radiation, Second Edition, Lewis R. Koller, Wiley, p. 153). Since then it has been consistently referred to in literature, books and by the industry etc. as the Bouger-Lambert law.
Secondly, Beer’s law is the name given to the law that defines UV dose to inactivate microorganisms as the product of UV germicidal intensity and time of exposure. This title has been recognized and used since time immemorial. The word Beer has no connection to the Bouger-Lambert law.
Also, while Dr. Bolton does acknowledge that the use of the words dose and dose rate are in common use against IUVA’s preferred choice of fluence and fluence rate, I have difficulty with this and it should be recognized that there is no cause for us at the business end of UV water treatment to rename the terms as is advocated. Dose and dose rate quite adequately express the functions in UV irradiation that they are meant to represent. They have been used for many decades, their concepts are well understood and they can also be interpreted correctly from our lives in general. For example, we can all relate to a a doctor telling us how many pills to take (the dose) and at what frequency to take them (the dose rate). Further, fluence is not in the two dictionaries that I have on hand—the Oxford Dictionary and the American Heritage Dictionary—and can cause confusion, whilst dose is in both and explains correctly the context. The layman can possibly presume fluence to be related to words in common usage such as affluence and influence etc. and this is totally misleading. Also in this context, other comparable irradiation technologies, including the electron beam irradiation area in which I spent 10 years as Manager with AECL (Atomic Energy of Canada Limited), relate and use the terms dose and dose rate in exactly the same context as used in the UV industry. Thus I do not see the necessity to go back on history and change the terminology for the sake of change. UV technology has only recently become fashionable and there is a preponderance of new younger technical members who either through ignorance or otherwise are misguidedly ignoring the past and attempting to redefine the UV technology as though they are the founding authors of it and seek to establish their position at the core of the technology. It is notable that most of the terminology and definitions in the IUVA paper are culled from draft papers etc. from 2000 onwards and from the papers’ authors and the name changes etc. like fluence are arbitrary and at the dictate of the authors of these draft papers and do not necessarily come from any requirement for standardization. The existing terms are already used to encompass the concepts defined for fluence in the paper and have stood the test of time. Changing the name does not change their meaning, so while the neophyte UV scientific community may find a need to manipulate UV technology terms, the long established practical UV industry and business—to avoid unnecessary confusion—should and will continue to use the perfectly adequate historical terminology.
This for your interest and if, as the caption on the paper heading says, Terms and Definitions do Matter—then they should at least be accurate and meaningful.
Dr. David Free, Ph.D. CEng MIChemE
Principal, DF Consultants