Water and Its Impurities [antikvár]

PREFACE Historically, the design of works for the conveyance, control, and treatment of water and wastewater during the nineteenth and twentieth centuries has been the responsibility of civil engineers. The development of hydraulics, hydrology, and structural theory and the techniques of application of these engineering sciences to the design of water and wastewater works must be credited to the civil engineering profession. The modern public health movement probably originated in England about the middle of the nineteenth century as a result of the intolerable sanitary conditions which developed upon the concentration of population in urban areas in the wake of the industrial revolution. A movement was started to promote better water supplies and more satisfactory methods of sewage disposal. Water supplies were purified, sewers were built, and attention was directed to methods of sewage treatment. This movement was initiated by public sanitary commissions and medical or health officers. The movement resulted in a reduction in the incidence of disease, although the causative agents of the diseases were not then known^ Beginning about 1880, a series of epoch-making discoveries in bacteriology demonstrated that specific microorganisms are responsible for many of the common diseases, anthrax, tuberculosis, cholera, typhoid fever, diphtheria, tetanus, plague, gonorrhea, pneumonia, and others. It was proved that the mere accumulation of filth was not responsible for disease, but that the diseases were transmitted from person to person through the agency of microorganisms. Some of these disease germs, notably the agents of typhoid fever and cholera, were shown to be waterborne, passing from the intestinal tract of infected persons through sewage to the drinking water of others. About 182il» chemists, biologists, and bacteriologists became involved in problems of water quality and water pollution. A start was made to instruct some civil engineers in water chemistry and water biology and bacteriology. Thus emerged the professional sanitary engineer. The Sanitary engineermg profession has, over the years, been principally responsible for the protection and improvement of our water supplies, for the development of sewage and wastewater treatment and disposal methods, and for water pollution abatement. Sanitary engineers have administered the pubUc agencies dealing with these problems, they have designed and supervised the construction of the water and wastewater works, and they have operated these works. Today, they are involved in many other engineering activities relating to the public health and comfort.