Water Purification in War
Major Howard McCyost
Quartermaster Service News
Reprinted in the Quartermaster Professional Bulletin – March 1988
Water purification during and after World War I
Wholesome drinking water has become recognized as one of the important elements entering into the conduct of warfare. Water is used for such a variety of purposes that it is absolutely necessary to both man and beast. Without water of any sort, an Army would soon become entirely demoralized and actually perish. With impure water, an Army must straggle along handicapped by various disorders which may be directly traced to the character of the water in use. Water is as necessary to an Army as food and transportation. It is far more necessary than either clothing or shelter.
To make water attractive for drinking purposes, it must be clear to the eye and sparkling. At the same time, as nearly sterile as it can be made under the conditions. Many diseases of men in the field can be traced directly to a spring or well that has become so foully polluted that it is the very essence of poison. It may be, therefore, assumed that one of the first, if not the prime, requisites for good morale is a sufficient supply of pure wholesome water.
Water coming from any source may be muddy or discolored to a point where it will be unsightly. When it is muddy and discolored, it generally contains many injurious elements which must be removed before it is in fit condition for general use. Again, raw water may be clear and sparkling and, at the same time, contain elements that are injurious to the health of the consumers. Therefore, it is necessary to have, in connection with the collection of water, a method for testing the quality by analysis. For turpidity, water is compared with standard samples having various known degrees of turpidity. The unit of turpidity is 100 and, is the turpidity of a water in which a bright platinum wire 1 millimeter in diameter may be seen through 1 centimeter of water. The comparative samples are arranged by dilution in distilled water in the ratio desired. Examination of water for bacterial contents involves a qualitative chemical analysis. Clear, sparkling water may contain bacilli coli to a count where the health of the community might be jeopardized by the use of the water. It can, therefore, be seen that appearances are quite deceptive and that any water that is intended for use should be carefully analyzed to determine its fitness. In the cantonments of the United States Army and the American Expeditionary Forces, permanent installations consisting of gravity filters and mechanical sterilizers were installed to ensure the health of the soldiers.
In the theatre of operations (near the front) it was impractical to have these permanent installations where rapid movement of the troops made them useless except to supply water for the water trains. It, therefore, became necessary to provide a means of examining and correcting the water encountered in this district, so that heavily contaminated water might be avoided and water that was not so heavily contaminated might be corrected to a degree where it could be made safe to use. Portable apparatus, such as Lister Bags and large canvas filters, was first developed; later on, a device which will be described in a succeeding paragraph was designed to replace in a measure the rough and ready expedient in use.
The filters used by the American Expeditionary Forces were those known as the gravity type, consisting of filter beds filled with sand and stone through which the water must percolate before reaching the outlet which connects with the distribution system. The operation of a typical filter may roughly be described as follows: Water is pumped into the tank, which is known as a dosing chamber, where it receives a treatment of an alum solution which is intended to coagulate the foreign elements in the water and form a substance known as flocce. The water flows very slowly through this dosing chamber and into what is known as a sediment bed where the rate of flowing is still slower–slow enough to cause the minute particles held in suspension that are heavier than water to drop to the bottom of the bed. The alum solution collects the particles which are not as heavy as the water and which are of the same specific gravity and forms them into a mass which is held separate from the water in a sort of gelatinous condition. These two processes reduce to a considerable degree the bacterial content of any water. The water then passes from the sediment bed out over beds of clean sand and stone of varying depths for filtering. The distribution of this water over the filtering beds is often accomplished by the use of a network of pipes laid in the sand, each pipe having many outlets which are terminated with sprinkling nozzles. The water is forced into the air where the sunlight and the oxygen of the air assist in the reduction of bacteria by an action known as aeration. As it flows upon the filter beds and gradually seeps through the various layers of filter material, the gelatinous flocce collects upon this filter material and is, thus, separated from the clear water. The turpidity is greatly reduced in the sediment bed, and final reduction to a point where it is clear and sparkling is accomplished in this filter bed. Thus, water is clarified and reduced to a certain degree in bacterial content, but still other processes must follow before safety in use can be assured.
We now approach the most recent development in the preparation of water for use. The purpose of sterilization is to render water entirely free of harmful bacteria. This ideal is not reached in practice, but modern devices have become so accurate that after water has been treated it is rendered absolutely safe for any purpose. The first method used in sterilization of water was distillation; that is, the water was formed into a vapor, the vapor was passed over certain chemicals, and the vapor was then recollected as distilled water. Another method of sterilization that has been tried and is still in use in many places is the treatment of water with certain salts of chlorine. This method has been replaced by a more scientific method largely because the percent of chlorine administered to the water could not be closely controlled due to the varying chlorine content of the salts used. Water sterilized by this method often has a strong taste and odor of chlorine which is decidedly disagreeable. Sterilization is accomplished in camps and cantonments by the use of permanent chlorine dosing stations. In the field and in the theatre of operations, portable apparatus has been developed which accomplishes the same purpose to a limited degree. The sterilization of water in our cities and also in our Armies is a safeguard against epidemics and has reduced the death rate due to disease very materially. In fact, cases are hard to discover where patients have contracted disease of a water-born variety where sterilized water has been used to the exclusion of all others. It is extremely difficult to control the drinking of troops. When a spring of clear, cold water is found, the water is generally used without regard to its content. It, therefore, became necessary for officers in charge of troops in the field to investigate the characteristics of the water that might be encountered by the troops and to prevent as far as possible the use of dangerous waters by providing sufficient sterilized water.
Sterilization equipment as used in the Army covers everything from lozenges of sterilizing chemicals which are placed in the canteens to highly developed dosing plants. Little need be said here of the ruder methods of sterilizing water except that each has its particular use. Most of the lozenges produced water which had a taste which was disagreeable to the user, consequently the lozenges were not used but were thrown away and dangerous water used in place of the bad tasting sterilized water. At all of the camps in the United States and at the permanent camps in France the American Army was equipped in addition to filters with up to date sterilizing equipment. Liquid chlorine compressed in steel cylinders was used instead of the salts used by other Armies. The amount of chlorine to be administered to the water was determined by analysis and an automatic regulating meter was used to insure the constant flow of the proper quantity of chlorine into the water. This measuring apparatus was extremely technical in operation and need not be described in detail here. It is sufficient to say that every gallon of water had its proper quota of sterilizing material injected into it before it was used. Oftentimes the amount of chlorine necessary to neutralize the bacteria in the water would be sufficient to cause a taste. This was overcome by the use of a dechlorinating agent such as soda thiosulphite. This chemical absorbed the excess chlorine and rendered the water acceptable for drinking purposes. The present advance in the science may be attributed directly to the war, as a development of portable apparatus for treating water in the field. This apparatus combines the analysis, filtering, and sterilizing of water in one unit. The entire unit was mounted upon a motor truck. The operation of the unit may be described as follows: Water encountered is first sampled and the samples taken to the laboratory for analysis for bacterial content. Here the amount of chlorine necessary to sterilize the water is determined. The water is pumped from this source by means of a pump, mounted integral with the rest of the unit, and forced into a dosing chamber where it receives the alum solution and thence into the pressure filter where it is clarified. Here the filtered water is forced through pipes and in its course treated with the correct amount of chlorine, by means of a special measuring device. After the chlorine has operated for sufficient time to render the water sterile a dechlorinating agent is administered in the form of sodium thiosulphite and the water sent to storage into two six hundred gallon tanks, fastened under the truck. Thus each unit is capable of providing 1200-gallons per minute of clear sterilized water for the use in the Army kitchens and for drinking purposes. It may here be said that the above device is strictly American. Practically all of the devices of a similar nature used by the British and French were designed by American Engineers. The success attained by the use of this apparatus is hard to estimate as it is not known how far impure water might have affected the troops. However, it suffices to say that the hospitals, cantonments, and even the troops in the field were provided with a means of obtaining suitable water for any purposes.
The collection of water in the field and in the camps abroad was under the control of the Corps of Engineers and the above devices were adopted and installed by the Engineers of the United States Army. The chemical analysis of the water was conducted by officers assigned to duty with the Engineers from the Medical Corps. The results achieved were; first, pure water; second, the death rate from water diseases was reduced almost to the figures obtained in civil life; third and last, a feeling of security from plagues and disorders that frequently reduce the morale of an Army to a very low figure. It can safely be said that that part of the Army engaged in the collection of water has rendered to the United States a service as valuable as that rendered by any branch of the Army.
EDITOR’S NOTE: This article is presented in the author’s original style as published in the 1920 Quartermaster News Service.