Popular Science Monthly/Volume 58/December 1900/Municipal Water-Works Laboratories
|MUNICIPAL WATER-WORKS LABORATORIES.|
By GEORGE C. WHIPPLE,
MT. PROSPECT LABORATORY, BROOKLYN, N. Y.
THE laboratory idea is fast taking hold of our municipalities. It is the natural result of modern science and American practicality. More and more our civilization is making use of the great forces of nature, and more and more is it becoming necessary that nature's laws should be understood: hence the need for the precise data of the expert and the long-continued observations of the specialist. This is emphatically true in the domain of sanitary science, where the advances in chemistry, microscopy and bacteriology have wrought revolutionary changes. The microscope is no longer a toy, it is a tool; the microscopic world is no longer a world apart, it is vitally connected with our own. The acceptance of the germ-theory of disease has placed new responsibilities upon health authorities and has at the same time indicated the measures necessary to be taken for the protection of the public health. With the knowledge that certain diseases are caused by living organisms find that these may be transmitted by drinking-water has come the need of careful supervision of public water supplies, which has resulted in the establishment of many laboratories devoted to water analysis.
The pioneer work of the Massachusetts State Board of Health and the Board of Health of New York City has been followed by the installation of laboratories in most of our large cities. In many cases these are operated in connection with departments of health, and the supervision exercised over the water supplies is of great benefit to the communities. An instance of this is furnished by the Health Department of Chicago. The water supply of Chicago is taken from Lake Michigan, and before the operation of the drainage canal the sewage of the entire city was discharged into the lake. The location of the water-works intakes was such that the water pumped to the city was subject to great changes in quality, varying from day to day according to the direction of wind and currents. For a long time it has been the practice of the department to issue daily bulletins as to the sanitary condition of the water in the city. Samples from the various sources of supply are received at the laboratory each morning, and upon the results of certain rapid methods of analysis the chemist bases his judgment as to the probable character of the water in the city mains during that day. The report is promptly given to the representatives of the press, and the consumers are thus warned of approaching danger.
The work of supplying water to a community is, however, an engineering problem, and for some years water-works' officials and engineers have felt the need of having in their own hands the means of determining the quality of the water. This has not been because they wished to assume duties pertaining to the health authorities or because they stood in fear of criticism, but because the management of the water supplies demands immediate information of a character not always appreciated by a physician and not always promptly obtainable from the laboratory of a health department. Accordingly, there has been developed in this country during the last decade an interesting group of water-works laboratories devoted to sanitary supervision and to experiments upon water purification.
The first of these laboratories was that of the Boston Water Works, established in 1889 by Mr. Desmond Fitzgerald, C. E., then Superintendent of the Western Division. At that time, and for several years previous, the water supplied to the city was in ill favor with the consumers because of its brown color and its vegetable taste. The primary object of the laboratory was the study of these objectionable conditions and the means for relieving them, but as the work proceeded it developed along broader lines. The laboratory, situated on the shore of Chestnut Hill Reservoir, consisted of a small frame building of two rooms, one used for general biological work and the other fitted up as a photographic dark room. The working force consisted of one biologist and three assistants, besides a number of attendants at the reservoirs, who devoted a portion of their time to the collection of samples and the observation of the temperature of the water. The following were the general outlines of the work:
The water supply of the city was derived from Lake Cochituate and from a series of storage reservoirs on the Sudbury River. The waters from these sources differed from each other and varied at different seasons of the year. Accordingly, a system of inspection and analysis was arranged in such a way that the superintendent knew at all times the exact condition of the water throughout the system. Samples of water were collected regularly from all streams tributary to the supply, from reservoirs at various places and at different depths, and from the aqueduct. and distribution pipes. When these reached the laboratory they were examined microscopically and bacteriologically, the presence of any odor-producing organism was carefully noted and an immediate report was rendered when necessary. Careful observations of color were also made. When the work in Boston was started the methods of biological examination of water were in their infancy. The Sedgwick-Rafter method of ascertaining the number of microscopic organisms in water had just been devised and the methods of plate culture of bacteria were just becoming popular. The new methods were adopted in the Chestnut Hill laboratory and constant use resulted in important improvements. The old method of obtaining the temperature of water beneath the surface by the use of a weighted thermometer gave way to the electrical 'thermophone’ and new methods for measuring the color of water were devised. An apparatus for photography was installed, and excellent photographs were made of all the important microscopic organisms in the water. A set of these photographs was on exhibition at the World's Fair in Chicago. In addition to the routine work, many lines of experimental work were undertaken. Studies were made upon the seasonal distribution of various organisms, the effect of temperature, light and air upon their growth, and upon the cause and nature of the odor imparted by organisms to drinking water. The effect of swamp-land upon water
supplies, the stagnation of deep lakes, the bleaching action of sunlight upon colored waters were likewise considered, while for several years the laboratory was operated in connection with an experimental filter plant. After the Metropolitan Water Board assumed control of the water supply of Boston and its suburbs the laboratory was moved from Chestnut Hill Reservoir into the city, where it now occupies rooms at No. 3 Mt. Vernon street. In 1897 Dr. F. S. Hollis succeeded the writer as biologist, and he in turn has been succeeded by Mr. Horatio N. Parker. During recent years the conditions of the water supply have changed. New reservoirs of large capacity have been built, and the great Wachusett Reservoir is in process of construction. Swamps have been drained and fillers have been installed where there was danger of polluted water entering the supply. Thus new fields of work have been opened to the laboratory. The center of gravity of the system is now much farther from the city than formerly, and the logic of the situation points to the future establishment of a laboratory upon the watershed operated in connection with a department of sanitary inspection and equipped for chemical as well as biological work.
In 1893 the Public Water Board of the city of Lynn, Mass., fitted out a small room in the basement of the City Hall to serve as a laboratory for microscopical work. Weekly samples were collected from the supply ponds and examined by one of the lady assistants in the office. The results of the examinations were used by the superintendent in the operation of the works, and in several instances
they proved the direct means of preventing the consumers from receiving water of an inferior quality. They also resulted in the undertaking of improvements in one of the reservoirs and tributary swamp areas that materially reduced the growths of troublesome algæ.
Bad tastes and odors in the water supply of Brooklyn, N. Y., led to the establishment of Mt. Prospect Laboratory by the Department of Water Supply in 1897. As this laboratory is typical of its class it deserves more than a passing notice. Situated upon the shore of Mt. Prospect Reservoir, near the entrance to Prospect Park, the laboratory has a fortunate location. In addition to being within convenient distance of the office of the department, the main distribution reservoirs of the city and the railway depot at which samples from the watershed are received, it-isolation and elevation make it comparatively free from noise and dust, while the building is well lighted by large windows, heated by hot water and provided with gas, electricity and telephone. The upper portion of the building contains three rooms, known as the general laboratory or [(reparation room, the biological laboratory and the chemical laboratory. In the basement are the physical laboratory, the furnace room and the general storeroom. The general laboratory is used for the shipment of samples, the washing of glassware, the sterilization of apparatus, the preparation of culture media and for such chemical processes as might charge the air with ammonia and the fumes of acids. The biological laboratory is devoted to the bacteriological and
microscopical examination of samples of water and to the study of the various organisms found. It also serves as the office of the director. The chemical laboratory is the largest of the three rooms. Its atmosphere is kept free from ammonia and acid fumes in order not to vitiate the results of the water analyses there carried on. Analyses of coal are also made in this room. A storage room opens from the chemical laboratory and there is also a small dark room. All three laboratories have marble tiled floors, and the tables and shelves are covered with white tiles throughout. The partitions between the rooms are largely of glass. The apparatus is of the most complete description, much of it having been designed for the particular work at hand. The physical laboratory in the basement contains all the necessary apparatus for testing cement, analyzing sand, etc. The laboratory force consists of one biologist and director, one chemist, one assistant chemist and three assistants.
The routine work of the laboratory consists of the regular examination of samples of water from all parts of the watershed and distribution system, i. e., from the driven wells, streams, ponds, aqueducts, reservoirs and service taps. The complicated and varied character of the water supply requires the examination of an unusually large number of samples, and it is safe to say that no water supply in this country is examined more thoroughly and minutely than that of Brooklyn. During the three years that the laboratory has been in operation over eight thousand samples have been analyzed.
The problems of the Brooklyn supply are very different from those met with in Boston. The supply is drawn, not from a few storage reservoirs of large size, but from a large number of small supply ponds, supplemented by an almost equal amount of water from deep and shallow driven wells. There are no extensive swamp areas, but the watershed is sandy and serves as a natural filtering medium. The entire supply, therefore, partakes largely of the character of ground water. The storage of ground water in an open reservoir has been almost always attended with troubles due to growths of microscopic organisms, and the Brooklyn supply has proved no exception to the rule. The mingling of surface water, seeded with plant life, and ground water, laden with plant food, has resulted in the enormous development of microscopic organisms in the distribution reservoirs. During the summer and autumn of 1896 the condition of the water in the city caused general complaint because of its bad odor. An examination, made by Dr. Albert R. Leeds, showed that the diatom asterionella was responsible for the trouble, and that the fishy odor was caused by an oil-like substance secreted by this microscopic plant. Since 1896 growths of asterionella and other odor-producing organisms have recurred regularly in the distribution reservoirs, but by the use of the new by-pass, through which water may be pumped around the reservoirs direct from the aqueduct to the distribution pipes, the water in the city has been kept comparatively free from them. The organisms appear and disappear according to laws that are now beginning to be understood, and while their growth in the Brooklyn reservoirs cannot be wholly prevented under present conditions, the laboratory is doing an important service by constantly noting their condition of growth and by forecasting their effect on the city supply for the guidance of the engineer in his manipulation of the reservoirs. The chief service of the laboratory, however, is in connection with the sanitary condition of the watershed, and upon this most of the bacteriological and chemical work is concentrated. The laboratory was-installed and equipped under the direction of Mr. I. M. De Varona, Engineer of Water Supply, with the writer in immediate charge.
The filtration of all surface water used for domestic supply is one of the probabilities of the future. For years many of the large cities of Europe have been supplied with filtered water, and in England alone more than ten million people are using water from which all danger from disease germs has been removed. In America filtration has gained ground but slowly, and in some of our cities the condition of the drinking-water is a disgrace to civilization. A German health officer once said to me: 'You Americans are a queer people; you filter sewage, but you drink water raw.' One reason for our tardiness in following the practice of the Old World is the fact that the conditions here are not in all respects the same as in Europe. The old methods of filtration cannot be successfully applied to many of our American waters, and water-works' engineers have felt that before expensive works were undertaken the problems should be carefully studied by direct experiment with respect to existing conditions. Thus, recent years have witnessed the operation of experimental filter plants unequalled in magnitude, in the scope of their work and in the accuracy of their methods of investigation.
The experiment station of the Massachusetts State Board of Health at Lawrence was started in 1897 and is still in operation. The results of the investigations of the principles involved in the purification of water and sewage by sand filtration have become classic in the annals of sanitary engineering, and the annual reports are still furnishing results of the highest scientific value. At the present time the work is in charge of Mr. H. W. Clark, Chemist of the Board. One practical result of these experiments was the construction of a sand filter of novel type for the purification of the water supply of the city of Eaw fence, and the immediate reduction of the typhoid fever rate showed the success of the undertaking. The water of the Merrimac River, at Lawrence, though polluted, is comparatively clear, and it became evident that methods of filtration that were applicable to water of this character would not be necessarily successful where the water was highly colored and turbid. Experiments were, therefore, begun in other cities.
In Boston, where the water was of higher color than at Lawrence, and where microscopic organisms were sometimes numerous, a filtration station was in operation from 1892 to 1895. Six sand filters, each within area, of one-thousandth of an acre, and a large number of smaller filters, were used under varying conditions. The station was in charge of Mr. Win. E. Foss, under the direction of Mr. Desmond Fitzgerald, C. E. The analytical work was done partly at the Massachusetts Institute of Technology and partly at the Biological Laboratory described above. It is much to be regretted that the results of these experiments were never published.
In 1893 Mr. Edmund B. Weston, C. E., of Providence, R. I., conducted for the water department of that city a series of experiments upon the purification of the water of the Pawtuxet River by means of mechanical filters. Though less extensive than the experiments above mentioned, they are of historic interest as giving the first adequate demonstration of the possibilities of that method of purification.
The system of mechanical filtration, or the 'American System,' as it is sometimes called, differs from natural sand filtration by the use of alum or some similar coagulating substance before sedimentation and filtration, by the higher rate of filtration employed and by the use of certain mechanical devices for cleaning the sand beds. The application of this process to the treatment of turbid water was next investigated. In 1895 the Louisville Water Company undertook a most extensive series of experiments to determine the relative efficiency of various types of mechanical filters in the purification of the water of the Ohio River. The work was placed in charge of Mr. Geo. W. Fuller, C. E., who was assisted by a large corps of trained assistants. For nearly a year the experiments were carried on without interruption: the filters were operated by the companies interested in them, and their efficiency was determined by Mr. Fuller on behalf of the water company, who had at hand a complete laboratory equipment and who used every means known to science in the analysis of the water before and after treatment. The most important result of these experiments was to prove beyond doubt the applicability of mechanical filtration to the purification of water rendered turbid by the presence of fine particles of clay.
The experiments in Louisville were followed in 1898-9 by a somewhat similar investigation at Cincinnati, 0., also conducted by Mr. Puller. As in Louisville, the water supply is taken from the Ohio River, but the character of the water at this point is not in all respects the same as that farther down stream. The problem in Cincinnati was to determine whether the English system of sand filtration or the American system, involving the use of a coagulant, was best suited to the purification of the water, and whether any preliminary treatment of the water before filtration was advisable. To solve this problem the Board of Trustees, Commissioners of Water Works, decided to appropriate for needed experiments a sum equivalent to about one year's interest on the probable cost of a plant for filtering the supply of the city. The equipment consisted of four steel tanks, each with a capacity of 100,000 gallons, fifteen experimental filters, arranged for operation under different conditions, and a large laboratory fully equipped for chemical and bacteriological work. After a period of continuous operation, covering about ten months, the evidence showed that either the American system or the English system operated with preliminary coagulation and sedimentation would satisfactorily purify the water, but that the American system could be operated with less difficulty and with somewhat less expense.
In 1896 the city of Pittsburg, Pa., appointed a commission to consider the character of the water supply and the advisability of its purification by some means of filtration. The supply is taken from the Allegheny and Monongahela rivers, streams which are often turbid and which are subject to contamination by sewage. The conditions were such that direct experiment was necessary to determine the most suitable system of purification. Accordingly, an experimental station was located on the shore of the Allegheny River and placed in charge of Mr. Morris Knowles, under the direction of Mr. Allen Hazen, Consulting Engineer. Arrangements were made for the comparative study of sand filters and mechanical filters, and a laboratory was built and equipped for making all necessary analyses. The plant was in continuous operation for more than a year, and the results seemed to show that while satisfactory clarification of the water could be obtained by either system, the method of sand filtration could be depended upon to remove more completely the effect of pollution.
The report of a similar series of experiments made to determine the feasibility of purifying the water of the Potomac River at Washington, D. C, has been issued by the War Department. The work was carried on in a manner similar to that at Cincinnati and Pittsburg, the object of the studies being to find the best method adapted to the local conditions. Col. A. M. Miller, XJ. S. A., had charge of the investigations, and Mr. Robert Spurr Weston conducted the analytical work. Recently the Department of Public Works, of Philadelphia, Pa., has established a testing station near the Spring Garden Pumping Station for the purpose of studying the problems of filtration incident to the construction of filter beds for the water supply of the entire city, for which the sum of ten million dollars has been already appropriated. The work is in charge of Mr. Morris Knowles. Still more recently a testing station has been established by the Sewerage and Water Board of New Orleans, with Mr. Robert Spurr Weston as Resident Expert.
In July,1899,the newly-constructed water filtration plant at Albany, N. Y., was put in operation, Mr. Allen Hazen having been Chief Engineer of construction and Mr. Geo. I. Bailey Superintendent of Water Works. In connection with this plant is a small laboratory in which are made daily bacteriological examinations of the water before and after filtration. Physical, chemical and microscopical examinations are also made at frequent intervals. The results obtained indicate the amount of purification that is taking place, and they already have shown that the filter is rendering efficient service in protecting the community from water-borne diseases.
The combined work of these various laboratories of supervision and experiment has been of incalculable benefit to sanitary science, and the results have been not only of local and immediate value, but they have acquired a world-wide reputation and form a permanent contribution to scientific literature. If one doubts the practical worth of a laboratory in the management of a water-works system, no more convincing argument could be presented than the fact that a private water company in Wilkesbarre, Pa., has recently gone to the expense of establishing a laboratory for chemical, microscopical and bacteriological analyses of the Water sold to the community, and this in spite of the fact that the water supply is taken from a watershed not seriously open to the danger of contamination. The work is in charge of Prof. Wm. H. Dean.
It is an interesting fact that in many instances the laboratories have been found to have a wider field of usefulness than that for which they were originally intended. For example, the laboratory in Cincinnati did not cease its existence when the filtration experiments were completed; it was continued as a laboratory for testing the materials of engineering construction. It is now in charge of Mr. J. W. Ellms, Chemist, under the direction of Mr. Gustav Bouscaren, Chief Engineer. The building has seven rooms and contains not only the apparatus necessary for water analysis and general chemical work, but a complete outfit for testing cement. The work now includes the chemical analysis of paints and oils, asphalts, rock, sand and cement, physical tests of cement, besides experimental investigations of the properties of cement mortars and asphalts.
At Pittsburg, also, the laboratory has been made permanent. The Department of Public Works has erected a two-story brick building, known as the Herron Hill Laboratory. The first floor and basement are used by the Bureau of Water Supply for water analysis, tests of supplies purchased and experimental work upon the filtration of water; the second floor is used by the Bureau of Engineering as a cement laboratory. In the water laboratory the floor and operating-shelves are covered with white tiles and the walls are painted with white enamel, so that the room may be washed from ceiling to floor. Steam from a neighboring boiler house is used for heating the water-baths and for distilling water. The incubators used for bacteriological work are placed in the basement, where the temperature can be kept more constant than on the floors above. The ammonia stills, sterilizers,and other apparatus are of the most modern type. A safe in the basement serves to protect the records in case of fire. One biologist, one chemist and one attendant are employed in the water laboratory, and a chemist is employed in the department of cement testing. Mr. Wm. R. Copeland is the biologist in charge.
In the Mt. Prospect Laboratory, of Brooklyn, the miscellaneous work is constantly increasing. The coal used at the various pumping stations is purchased under specifications that require the analysis of a sample that must accompany every bid, and the determination of the heating power of a sample from every consignment. Lubricating oils, boiler compounds, samples of steel and other materials are analyzed and the laboratory is also equipped for the chemical and physical testing of cements.
Other departments of municipal work are taking up the laboratory idea. The Sewer Department of Worcester, Mass., has two laboratories. One is located at the disposal works and is devoted wholly to the supervision of the process of treatment of the sewage. The other occupies attractive rooms in the City Hall. Here a great variety of work is undertaken. During the year 1899 more than a hundred carloads of cement were used by the department, and over eight thousand samples were tested for tensile strength; many chemical analyses were also made. Bricks were frequently tested for absorption, and several samples of steel used in the construction of shovels and offered to the department by different dealers were analyzed. Coal, oil, lime and many other materials purchased by the department were analyzed. In addition to this, over seventy-five samples of butter and oleomargarine were examined for the Department of Milk and Butter Inspection, and a number of water analyses were made for the water department. A large amount of experimental work was carried on in connection with the problem of sewage disposal. Both laboratories are under the general direction of Mr. Harrison P. Eddy, Superintendent of Sewers.
It seems apparent, therefore, that the laboratory is destined to be an important factor in municipal engineering as well as in municipal sanitation, and it is not difficult to foresee a time when every city of importance will be provided with a laboratory equipped in accordance with its needs. In large cities, work of this kind is preferably specialized and distributed through different departments, in order that it may be under the control of those directly interested in the results, but in small cities, all the analytical work can be more economically accomplished in a single laboratory. In such a laboratory the work would cover a very broad field. Coal, cement, oil, brick, asphalt and various structural materials would be tested before purchase and during delivery; illuminating gas regularly examined; water, milk and various food products analyzed to determine their purity and healthfulness; bacteriological cultures made for diagnosis of diphtheria, typhoid fever, tuberculosis and kindred diseases; disinfection of buildings supervised, etc. All this would require the services of an engineer, a chemist and a bacteriologist, or of these three combined in one person. The expense of such an institution would be small in comparison with the saving that would result to the citizens in the purchase of supplies and in the protection of the public health.