WATER TREATMENT FOR RAILROADS
I will forego the usual preliminary of the water treatment paper, and in this article presume that all present are duly familiar with the tacts of how the gentle rain from heaven absorbs the various mineral impurities in its course along the earth beneath. Needless to say they are present in varying amounts in all waters available for consumption, and cause numerous troubles in the manufacture of steam power through the formation of scare in the boilers and from the alkali water carried over into the steam heads in the case of foaming. Those of you who are not directly connected with the operation of steam plants have witnessed this phenomena ot scale formation in the common household kettle, and exercising imagination may be able to conceive of the considerable amount which is similiarly formed in the large locomotives of 2,500 square feet of heating surface and evaporating over 5,000 gallons of water per hour. This scale formation greatly lessens the life of the boiler and appurtenances, also necessitating frequent costly repairs with loss of use of expensive machinery, and delays to traffic from leaks caused by scale opening the flue joints. In the case of the household kettle after the worthy husbandman has wearied of his efforts in scraping out the persistent scale or has punched a hole through the bottom during the course of the proceeding, it can be turned over to the ashman and its successor procured for a very nominal sum. In the case of the locomotive the “nominal” sum is around $20,000.00, so that it is obviously to the advantage of those concerned to prolong the life and service by every economical means, and to reduce the cost of repairs and time lost as far as possible. The scientific investigation of this economy is of comparative recent development, that is, it having been worked out principally in the past fifteen years. It is no longer an experiment. although as with many innovations it is still regarded in a few places with suspicion. Although originating in England, if the report of the International Railway Congress of 1910 at Berne can be taken as a criterion, the United States leads the world in water softening efficiency. On the generally softei waters of the Eastern part of the country the process was first tried with most gratifying results. On the harder and heavy scale waters of the middle West and Western districts it is now regarded as a practical necessity. In cases where it has been successfully installed and competently operated the increase in the life of flues has amounted to from 75 per cent, to 150 per cent. The report of the Committee on Water Service for the 1914 convention of the American Railway Engineering Association shows that on six representative trunk lines through the middle West there are now in service 237 complete treatment plants and 111 soda ash partial treatment stations, ranging from 5 complete plants on one road to a maximum of 112 on another, and from no soda ash plants on several to 86 on one. Resides this several railroads arrange for placing soda ash directly into the engine tanks at the terminals. This is conducive to foaming conditions, but the economy derived from the scale removal more than justifies the foaming complaints. On the road with which I am connected there are at present 45 complete water softening plants in operation, the majority being on the hard waters west of the Missouri River. The average amount ot water treated per year, reducing the hardness so that it will form practically no scale, is 1,693,000,000 gallons. The total average amount of scale removed from this water is 5,537,000 pounds, which would make over 110 carloads at 50,000 pounds each, a considerable amount when it is remembered that but for treatment this scale would have to go through the engine boilers and most of it removed by taking the flues out. The total annual cost for the above treatment including chemicals, additional supervision necessary, maintenance, interest and depreciation on plants is about $65,000.00. However, conservative figures show that with this expenditure there is a net saving of about $105,000.00, from cutting down the following losses alone
•Paper read at the Illinois Water Supply Association Meeting.
- —Frequent renewal of flues and other parts of boiler account of scale accumulation and injury to flue ends from repeated caulking.
- —Labor caulking flues and other engine house boiler repairs.
- —Loss of engine time during boiler and firebox repairs.
- —Loss of fuel due to the insulating effect of the scale on the flues and other heating surfaces.
Besides these are the indeterminate benefits in the road performence of locomotives by reducing the failures and interruption to traffic with the reduction of the number of locomotives required for a given traffic. On one terminal alone approximately 18,000,000 gallons of water are treated monthly, eliminating 5 pounds of scale per 1,000 gallons for a total of about 80,000 pounds per month. The cost for chemicals for this is about 4 cents per 1,000 gallons or a total monthly bill of about $720.00. The length of life of flues using the straight raw water before the installation ot the softening plants was from 8 to 12 months with serious trouble on account of frequent leaks. The locomotives now using the straight treated water average 18 months between shopping and the trouble with leaky flues is practically eliminated. At another terminal about 30,000,000 gallons of water are treated monthly, removing 3 pounds of scale per 1,000 gallons for a total of about 90,000 pounds. Prior to the installation of the softener, five boilermakers, days and foul boilermakers nights were employed caulking flues. After treating plant was put in operation this was reduced to one man, days, and one man. nights. The saving in this one item alone is $5,712.00 per year on an $8,000.00 investment. The life of the flues has increased from 8 to 12 months. In most cases where softening plants are installed the foaming conditions are increased, especially for the first few days after the treatment is started, due to the fact that the old scale in the boilers is lessened and, falling off. increases the amount of suspended matter in the water making a dirty boiler which seems to be the most important of the contributary causes of foaming. To soften a water to three grains per gallon or less of incrusting salts, which is the object in most cases, demands a purity in this respect of 3 parts in 58,341 or 99.995 per cent. This merely shows the deceptiveness of reporting water softening on the percentage basis, for although sounding complex is a comparatively simple matter. However, each individual water has its peculiarities such as temperature at different seasons and the difference in content of magnesium salts which
slow up the reaction and without due allowance for same leave a milky water as a final product. Creek waters of course change with the precipitation and l have also found that in some parts of the country well waters become softer in winter while others get harder. So far the development of water softening on a large scale has centered around lime and soda as being the chemicals which produce the results for the least cost However, Barium Hydrate is the ideal reagent on account of its leaving no detrimental byproducts as in the case of soda ash. So far the expense has retarded its development. Numerous boiler compounds through the high degree of exploitation obtained have been tried by a few railroads but investigation would show that even where the work desired was done the cost greatly exceeds that of the recognized methods. Inert powdered graphite is now being largely exploited as a cure-all for scale troubles, but its economical merits are yet to be proven. The “sunlight on corrugated aluminum” patent which was supposed to render the scale inert in the water without removing it chemically has been tried at several points in this section and seems to have proven unworthy. The Pernnititt water softener, the artificial zeolite, discussed by Mr. J. F. Garrett at our last meeting, has the objection in railroad work of replacing the incrusting carbonates with sodium carbonate, that is, waters which are sufficiently hard to warrant the expense of treatment as a rule contain sufficient incrusting carbonate, which if replaced by sodium carbonate could not be used on account of foaming properties. Therefore, it would seem that common lime and soda ash will continue to remain in service.