消防和水工程

消防和水工程

倾向于采购水from distant sources has developed to a large extent in this country within a comparatively short time. On the other side of the Atlantic there are many precedents to show that where local environments would not permit continuing the use of waters supplying urban populations, it became necessary to use other sources many miles from the places to be supplied. Thirty years ago Liverpool tapped the Vyrnwy watershed, eighty miles from that city, and previous to that time Dublin completed an excellent gravity supply of pure water from the Vartry river in the county Wicklow, nearly twenty miles out, with sufficient elevation to furnish ample pressure for fire service. And so on many other cases might be quoted to show that these expensive systems had to be adopted to meet the demands that then existed for improved supplies. Owing probably to the sparseness of the population of this continent, it was not until recent years that large projects of a similar kind had to be undertaken, to provide adequate permanent supplies, where previous conditions for that purpose had failed. Boston, Los Angeles, New York and other cities have been compelled to construct systems miles from their centres and involving immense expenditures of money in order to establish works that will furnish plenty of good potable water for these communities for many years to come. Philadelphia chose filtration of its present supply rather than the adoption of another and distant source, which was under consideration at the time the filter plans were decided upon. It will, however, always prove a troublesome task to keep those filters in condition as the water to be filtered is both turbid and polluted and will likely become more so as the population of the city increases. So it is that at no distant date we may expect to see many places being forced to abandon their present sources or resort to filtration. The American system of water purification is relied upon as it is easily adapted to places where defects were found in the existing supplies, rather than to resort to the more expensive plan of going a distance for a new source and in many cases such sources are not available. This mechanical filtration proved effective and economical in rendering good, potable water, where before introduction, it had become decidedly objectionable and almost unfit for domestic use. To show how successful this method became, it may be stated that there are now over three hundred cities using it with the most satisfactory results. Where communities take their supplies from the lakes it has been necessary to construct new cribs and intakes further out, as the polluted zone widened. Chicago, an example of this kind has had to build its latest intake crib six miles out from shore, where originally it received its supply from a distance of only two miles from shore and the same is the case with Cleveland. Cities along the rivers have to depend on the streams contiguous to them for supplies and it is these places that have been obliged to resort to filtration. Turbidity, discoloration and suspended matter are prevalent obstacles to maintain these sources for domestic use, so that a large number of cities, along the Mississippia and Missouri rivers particularly, have long since been compelled to use artificial means to render their supplies fit for domestic use. In the middle states where wells from the principal sources of supply much care has to be exercised to prevent waste, as subterranean water is more or less of an uncertain quantity. One thing is certain that where water supplies have to be obtained from adjacent sources both filtration and meterage must be adopted in order to furnish water of good quality and at rates that will meet the approval of consumers. By making future calculations along these lines the waterworks companies will save considerable trouble and be in a position to claim fair compensation on their investments. Where, however, it is possible to bring water from mountainous and unpolluted sources and furnish gravity pressure for domestic and fire purposes, no doubt ought to exist as to the expediency of procuring such systems with as little delay as possible.

在最近的一次revelat芝加哥表示惊讶ion, apparently based on substantial authority, that of the 467,772,000gallons of water. representing the average daily pumpage during a year, and allowing for a per-capita consumption of 204gallons per day, at least 75 per cent. was wasted, or disposed of without yielding any return to the city, by devious methods, involving surreptitious supply to corporations and other methods not strictly allowable. The experience of Chicago, in this respect is like that of hundreds of communities in all parts of the country. They are paying year after year, for the pumping, treatment, storage and distribution of a large quantity of water from which neither the community nor the consumer derives the least benefit. That the prevention, in large part of this waste, can be accomplished at once and effectively, has been demonstrated again and again where cities, determined to stop it have adopted the simple expedient of metering all services. Commencing with consumers who arc found, on investigation to be wasting water, or at least consuming much more than their share, the installation of meters is made compulsory. Sufficient evidence is presented in every issue of FIRE AND WATER ENGINEERING to demonstrate the effectiveness of this course against wanton waste. The immediate decrease in the quantity of water pumped, with a corresponding reduction in pumping station expenses, and, where water is filtered, in the amounts, is the result. Not only this, but in many instances where the supply of water threatened to be inadequate and the adoption of new sources of supply were regarded as inevitable, the employment of meters has caused such a stoppage of waste that the supply proved adequate for all purposes for many years to come. The expense of the contemplated additions were in consequence, indefinitely deferred. The plan to be followed in securing the universal metering of a city’s water supply, whether meters be owned by the community or by the consumer, there ought to be no hesitancy about placing them on all services to secure a complete system of check ing waste. But, whether the consumer or the municipality pays the expense of the meter, it has been proved time and again, that in both directions a saving is affected to the consumer, in that he pays only for what he uses and is not called upon to share the cost of what other people are recklessly wasting. It will be to his own interest to avoid the common causes of waste, such as leaking fixtures, faucets left running at all times and other means of waste, for all of which the meter makes his pocket responsible. The metering of all supplies, in a city of the magnitude of Chicago, is naturally a formidable undertaking, but even this can be effected by dividing it into sections and appointing a time for the metering of every service in each section, as has been done in many other cities. Long before the metering is completed, the advantages of the system have been realized, and in not a few instances have been so apparent, that the appointed time, for the completion of the metered service, has been curtailed. A community that tolerates such a state of affairs as Chicago complains of, does so with its eyes open and at its own expense.