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Recent research
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RECENT
RESEARCH.--FILTRATION
RECENT RESEARCH. ON THE PURIHCATION OF SEWAGEBY SUBSIDENCE.
OF WATER.
T H E F I L T R A T I O N O F W A T E R . a: By C. R. MACDONALD,M.D., D.P.H., Medical Officer of Health for the County of Ayr. Hfihner has investigated at Halle the effect of IT appears that the theory ot the purification of simple subsidence. H e gives an interesting and water by filtration has of late undergone considerelaborate description of the University buildings able modification. ~t has now been clearly and the sewerage thereof. T h e authorities forbid demonstrated through?the investigations of Koch, the direct introduction o f the hospital discharges Frankland, and others that a new filter composed into the town sewers as being highly dangerous to of perfectly purified sand has comparatively little the community. T h e sewage of the University, effect in producing either chemical or bacterioetc., passes into two large basins, where the logical purification of water. This view certainly suspended material is allowed to deposit and upsets all our preconceived ideas of the purification floating substances removed, the fluid contents of water by passing it through sand and gravel. passing o n without hindrance. T h e closets and It has been shown experimentally that although a drains are .purified by Friedreich's disinfectant, clean sand filter is unable to satisfactorily purify a consisting of i o per cent. carbolic, 35 quicklime, water polluted with organic matter, yet in the course i S hydrate of iron, and 3 per cent. alumina. This of use a layer charged with living microbes is prevents the development of germs and the evoludeposited upon the surface, and it is by these tion of noxiohs gases. As a result of these experiorganisms, which constantly increase in number, ments, he found that 94 per cent. of the solids and also penetrate the sand to a slight distance, are removed before entering t h e town sewers. that both the nitrification of organic matter and the (Hiihner, "Archly. fiir Hygiene," Vol. xviii.) arrest of other microbes are effected. Thus, the AN :EASY METHOD OF STERILISING WATER. longer a filter has been in use the more efficient it becomes, provided, of course, that the surface M'oritzTraube recommends a solution of chloride layer has not acquired such density as to interfere of lime. H e finds that a solution containing with the passage ot the water. T h e frequent 0000426 gramme, when a d d e d to too c.c. water cleansing of the filter-beds as had been formerly containing bacteria in large amount, destroyed all thought to be the proper method, now appears to in' about two hours. T h e water was shown to be have been a mistake. T h e filtration of the London b e e from germs by means of suitable nutritive water supply is no~¢ carried out on the method media, as Koch'-* bouillon. After two hours the recommended by Koch and Frankland, and the chlorine was only diminished to the extent of 9 per regularly conducted bacteriological examination of cent, I n order to rem'ove the excess of chloride of lime, the addition of o'oco2 gramme sodium • these waters by Dr. Frankland shows that when filtration is efficiently conducted 9 s to 99 per cent., sulphite was sufficient. An excess of the latter and sometimes even the whole of the microbes are :substance is not of much consequence, inasmuch removed from the samples examined, t We can as it is conve, ted into sodium sulphate alter the thus see that by proper filtration a doubtful supply lapse of a few hours. By the addition of these of water may be rendered almost absolutely safe. two compounds the hardness is only increased o'7 :But as this artificial barrier to its pollution will be degrees (German). One million cubic metres of subject to break down at any moment, the wisdom water require 85 cwt. of chloride of lime and of providing a water supply from a source which 4 ° c~t. of the sulphite. would render it independent of filtration must be I t is interesting to note that the organic matter apparent. Koch gives a very forcible illustration of the sterilised water was practically the same after of the importance of filtration. H e points out that the action of the chloride ot lime. I t seems, both the towns of Hamburg and Altona in i892 therefore, that the chlorine acts chiefly on the obtained their water supply from the E!be, which microbes. Traube made no experiments on pathocaused the serious epidemic of cholera in Hamburg, genic microbes, but trom the researches of Koch whiie Ahona escaped, although the former drew and of Nissen ("Zeitschrift fiir Hygiene," Vol. viii., its water from the river above the town, where it p. 62) it is probable that they are also destroyed. was comparatively pure, while Altona took water T h e author recommends this method for employlower down, where the river was very much fouler ment on the large scale as being cheap, feasible, and reliable. (Moritz Traube, "Zeitch. fiir Hyg,," owing to its having received the drainage of Hamburg. Altona practically escaped the visitaVot, xvi., Part I, February, i894. ) tion of cholera, whereas Hamburg suffered severely. At the latter the water was delivered unfiltered, but at Altona it was carefully filtered. F ~ o ~ a recent report by Dr. E. Klein, F.R.S., One group of workmen's houses in Hamburg was i t appears that the addition of a few drops of Jeyes' fluid to an agar cultivation of the influenza * From Dr. Macdonald's Third Annual Report. bacillus produced sterilisation, while the presence ~t" Vide Repor~ of the Royal Commission on the Water o f carbolic acid did not interfere with its growth. Supply of the Metropolis, London, I893.
RECENT
RESEARCH.--FILTRATION
RECENT RESEARCH. ON THE PURIHCATION OF SEWAGEBY SUBSIDENCE.
OF WATER.
T H E F I L T R A T I O N O F W A T E R . a: By C. R. MACDONALD,M.D., D.P.H., Medical Officer of Health for the County of Ayr. Hfihner has investigated at Halle the effect of IT appears that the theory ot the purification of simple subsidence. H e gives an interesting and water by filtration has of late undergone considerelaborate description of the University buildings able modification. ~t has now been clearly and the sewerage thereof. T h e authorities forbid demonstrated through?the investigations of Koch, the direct introduction o f the hospital discharges Frankland, and others that a new filter composed into the town sewers as being highly dangerous to of perfectly purified sand has comparatively little the community. T h e sewage of the University, effect in producing either chemical or bacterioetc., passes into two large basins, where the logical purification of water. This view certainly suspended material is allowed to deposit and upsets all our preconceived ideas of the purification floating substances removed, the fluid contents of water by passing it through sand and gravel. passing o n without hindrance. T h e closets and It has been shown experimentally that although a drains are .purified by Friedreich's disinfectant, clean sand filter is unable to satisfactorily purify a consisting of i o per cent. carbolic, 35 quicklime, water polluted with organic matter, yet in the course i S hydrate of iron, and 3 per cent. alumina. This of use a layer charged with living microbes is prevents the development of germs and the evoludeposited upon the surface, and it is by these tion of noxiohs gases. As a result of these experiorganisms, which constantly increase in number, ments, he found that 94 per cent. of the solids and also penetrate the sand to a slight distance, are removed before entering t h e town sewers. that both the nitrification of organic matter and the (Hiihner, "Archly. fiir Hygiene," Vol. xviii.) arrest of other microbes are effected. Thus, the AN :EASY METHOD OF STERILISING WATER. longer a filter has been in use the more efficient it becomes, provided, of course, that the surface M'oritzTraube recommends a solution of chloride layer has not acquired such density as to interfere of lime. H e finds that a solution containing with the passage ot the water. T h e frequent 0000426 gramme, when a d d e d to too c.c. water cleansing of the filter-beds as had been formerly containing bacteria in large amount, destroyed all thought to be the proper method, now appears to in' about two hours. T h e water was shown to be have been a mistake. T h e filtration of the London b e e from germs by means of suitable nutritive water supply is no~¢ carried out on the method media, as Koch'-* bouillon. After two hours the recommended by Koch and Frankland, and the chlorine was only diminished to the extent of 9 per regularly conducted bacteriological examination of cent, I n order to rem'ove the excess of chloride of lime, the addition of o'oco2 gramme sodium • these waters by Dr. Frankland shows that when filtration is efficiently conducted 9 s to 99 per cent., sulphite was sufficient. An excess of the latter and sometimes even the whole of the microbes are :substance is not of much consequence, inasmuch removed from the samples examined, t We can as it is conve, ted into sodium sulphate alter the thus see that by proper filtration a doubtful supply lapse of a few hours. By the addition of these of water may be rendered almost absolutely safe. two compounds the hardness is only increased o'7 :But as this artificial barrier to its pollution will be degrees (German). One million cubic metres of subject to break down at any moment, the wisdom water require 85 cwt. of chloride of lime and of providing a water supply from a source which 4 ° c~t. of the sulphite. would render it independent of filtration must be I t is interesting to note that the organic matter apparent. Koch gives a very forcible illustration of the sterilised water was practically the same after of the importance of filtration. H e points out that the action of the chloride ot lime. I t seems, both the towns of Hamburg and Altona in i892 therefore, that the chlorine acts chiefly on the obtained their water supply from the E!be, which microbes. Traube made no experiments on pathocaused the serious epidemic of cholera in Hamburg, genic microbes, but trom the researches of Koch whiie Ahona escaped, although the former drew and of Nissen ("Zeitschrift fiir Hygiene," Vol. viii., its water from the river above the town, where it p. 62) it is probable that they are also destroyed. was comparatively pure, while Altona took water T h e author recommends this method for employlower down, where the river was very much fouler ment on the large scale as being cheap, feasible, and reliable. (Moritz Traube, "Zeitch. fiir Hyg,," owing to its having received the drainage of Hamburg. Altona practically escaped the visitaVot, xvi., Part I, February, i894. ) tion of cholera, whereas Hamburg suffered severely. At the latter the water was delivered unfiltered, but at Altona it was carefully filtered. F ~ o ~ a recent report by Dr. E. Klein, F.R.S., One group of workmen's houses in Hamburg was i t appears that the addition of a few drops of Jeyes' fluid to an agar cultivation of the influenza * From Dr. Macdonald's Third Annual Report. bacillus produced sterilisation, while the presence ~t" Vide Repor~ of the Royal Commission on the Water o f carbolic acid did not interfere with its growth. Supply of the Metropolis, London, I893.