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JOHANNES MEIJER uvh2o at comcen.com.au
Sun Nov 1 22:13:12 EST 1998

Question on UVc Dosage CALCULATION
How do I arrive at the correct dosage, given the following information

Information that I have on a UVc Germicidal lamp is that it is powered with
15 watt 12V Dc inverter.
Lamp is 17 watts  and its actual UV output is 5 watts.
According to the lamp manufacture at 1 Meter the UVc lamp produces 45
microwatts per SQ Centimetre.
Wave length is 253.7 nm
As for water temp, that will vary from tap to tap , unit could be used in
various situations in various countries. I would presume that one could
perhaps quote an average temp taking in consideration  reasonable
As for a water transmission coefficiency   the device is to be used with
water that has already been subjected to pre-filtration 5 micron and is
recommended to be used with clear potable drinking water.
However the organism that it will need to target will depend upon its
efficiency and UV output water flow etc. Flow rate at
600Kpa using 3/8'' tubing is 3.4 Lpm, and using 1/4''tubing is
10 Lpm this should help in the quotation of dose rate.
The are a number of organism to target and I feel the best way to look at
this is to target those that require a high dose and work down from there,
but some require a higher dose than others, eg Cryptosporidium but no one
seems to know the required dose to neutralise this one including ,
Bilharzia and Giardia. I suspect it requires more than 100.000 microwatts
per cm sq.
Here is an indication of dose required for various bacteria etc

-------- -----------
Agrobacterium tumefaciens 8500 Mucor ramosissimus 35200
Bacillus anthraci 8700 (white gray)
Bacillus megaterium (vegatative)2500 Penicillum expensum 22000
Bacillus megaterium (spores) 52000 Penicillum roqueforti 26400
Bacillus subtilis (vegatative) 22000 11000 (green)
Bacillus subtilis (spores) 58000
Clostridium tetani 22000
Corynebacterium diphtheriae 6500 ALGAE
Escherichia coli 7000 -----
Legionella bozemanii 3500
Legionella dumoffii 5500 Chlorella vulgaris 22000
Legionella gormanii 4900
Legionella micdadei 3100
Legionella longbeachae 2900
Legionella pneumophila 3800 VIRUSES
(Legionnaires disease) -------
Leptospira interrogans 6000
(Infectious Jaundice) Bacteriophage 6600
Mycobacterium tuberculosis   10000 (E. coli.)
Neisseria catarrhalis 8500 Hepatitis virus 8000
Proteus vulgaris 6600 Influenza virus 6600
Pseudomonas aeruginosa 3900 Poliovirus 21000
    (laboratory strain) Rotavirus 24000
Pseudomonas aeruginosa     10500
(environmental strain)
Rhodospirilium rubrum 6200 YEAST
Salmonella enteritidis 7600 -----
Salmonella paratyphi 6100
(Enteric fever) Baker's yeast 8800
Salmonella typhimurium     15200 Brewer's yeast 6600
Salmonella typhosa 6000 Common yeast cake 13200
(Thyphoid fever) Saccharomyces var. 13200
Sarcina lutea 26400 ellipsoideus
Serratia marcescens 6200 Saccharomyces sp 17600
Shigella dysenteriae 4200
Shigella flexneri 3400 CYSTS
(Dysentery) _____
Shigella sonnei 7000
Staphylococcus opidermidis 5800 Cysts normally cannot be killed
Staphylococcuc aureus 7000 with UV, but are removed with
Streptococcus faecalis     10000 a sub-micron filters.
Streptococcus hemolyticus 5500
Streptococcus lactis 8000
Viridans streptococci    3800 Cysts include Giardia Llamblia
Vibrio cholerae (Cholera) 6500 and Chryptosporidium.
I hope this information will help .

Thank you in advance for your time and effort.

Regards, Johannes Meijer.         uvh2o at comcen.com.au
FAX 61 2 98749119
Sydney Australia.

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