APPENDIX.

APPENDIX A.

SEWERAGE-SYSTEMS OF LARGE CITIES.

London. When water-closets were first introduced in this city, about the beginning of the present century, they were connected with the sewers. The latter were large and badly constructed ; and the pollution of the soil became so great that a law was passed forbidding their use as a means of discharge for the water-closets or privies. Cesspools were then built all over the city, and the nuisance so increased that another law was passed, in 1847, requiring that they should be abolished, and that connections should in all cases be made with the sewers.

The contamination of the soil from these various sources became so great, that in 1866, during the cholera epidemic, posters were placed upon all the city pumps, stating that the water was none of it fit for drinking purposes. Even at the present day cases of illness are not unfrequently traced to buried and forgotten cesspools, and many polluted wells are still in use.

In 1856 the stench from the discharge of sewage into the Thames had become intolerable; there had been two recent epidemics of cholera in the city (in 1849 and 1854), and the many evils in the sewerage system had become so great, that engineers and physicians had united in declaring the necessity of a change. As a consequence, the main-drainage scheme was adopted, consisting of five sets of intercepting sewers, with four pumping-stations.

The two outlets for the northern and southern sections of the metropolis are at Barking and at Crossness, respectively ten and fourteen miles below the city proper; and they are covered by the water at the time of discharge. At each outlet there is a reservoir capable of containing the ordinary sewage of twenty-four hours, if necessary. The discharge into the river from these reservoirs takes place only during the two hours succeeding high water, so that an abundance of time is given for the ebb-tide to carry all the sewage to a safe distance.

Ventila

In the City of London proper, where the land is quite high, the sewers are well flushed, and they are ventilated by gratings placed at intervals, from one hundred feet to fifty yards apart, opening directly into the streets. Where the sewer-gases are especially foul, they pass first through charcoal filters. tion is also got in the different parishes by extending the soil-pipes through the roofs, by special pipes carried up above the tops of the houses, and in some cases by connecting rain-water spouts with the sewers without traps.

The sewers of the main-drainage scheme are self-flushing, and are a perfect success; and the pumps work admirably, so that places so low that they must be protected from the Thames by embankments are thoroughly drained.

Many of the old sewers, however, especially where the sand and dirt from the streets are discharged directly into them, require cleaning from time to time. This is done by contract, and inspections are made every three months by the Sewer Department to see that it is properly done. They are also flushed by gates which hold the water back until the sewers are nearly full, and then, being suddenly opened, let it go with a rush.

Since the intercepting sewers were built, the level of the groundwater has been very much lowered, cellars formerly wet have become dry, and, in some few places, trees are even dying from loss of moisture in the soil.

The storm-water is discharged into the Thames by overflows, some of which are so low that they are tide-locked at high water. Consequently, in case of very heavy rain at high tide, which indeed. does not often happen, those cellars which are placed below the grade established by the city authorities are liable to be flooded. This difficulty, however, has been obviated for a great part of the city by means of a sewer for surface water only.

All the attempts to utilize the sewage of London have proved failures from a pecuniary point of view. There is no nuisance to the metropolis created by the discharge into the river, and the surveys of the Board of Works convince them that the harbor is not filling up at all from sewer deposits. In fact, Sir Joseph W. Bazalgelte has given an opinion that the sewage actually helps scour the channel. All of the sewage of London goes into the Thames except that corresponding to a population of 20,000, which is utilized, at some pecuniary loss, on an experimental sewage-farm at Barking.

Liverpool. The drainage of this city is a comparatively simple matter. Most of the land is quite high, and there are only 5,210 acres. The sewers are, generally speaking, excellent. There are nine main branches, each having a separate drainage-area, discharging into the Mersey at deep water, in one case by a siphon, and at points eight feet below high-water mark.*

In the low part of the city there are nearly three hundred acres occupied chiefly by warehouses and drained by tide-locked sewers; and, in case of heavy rain at high water, the damage done in the cellars of this district has sometimes been very great.

At the summits of the new branch-sewers, reservoirs are made of about five hundred cubic feet capacity, to be used for flushing purposes. In many cases, too, similar reservoirs are making for the old sewers, so that there will be finally several hundred of them; and they will be used as often as frequent inspection shows flushing to be necessary. It is thought that some of them will never be needed.

The plans of all new sewers and of all alterations in the old ones

* The tide, as in London, rises and falls about twenty feet.

must be submitted to and approved by the Health Committee before they can be carried out.

In the lower parts of the city nearly three thousand pipes have been carried from the sewers through the roofs of the houses, to be used exclusively for ventilation. There have been complaints of bad odors from them in only two or three instances, in which cases they have been removed. Charcoal filters were used, too, at one time at the upper ends of the pipes, but were soon abandoned, as they were found to obstruct the passage of the sewer-gases.

In the better parts of the city, soil-pipes are carried up through the roofs, and rain-water spouts are used as ventilators in many cases where their upper ends are remote from chimneys and windows. The Sewer Department is also constructing ventilating shafts alongside of the manholes, and opening directly into the streets. The street-gullies are trapped, and are flushed in the summer time, so that they never shall become dry.

A few years ago the sewage was carried to a point north of the city and delivered by pumps upon a farm for irrigation; but the whole process was found so costly that it had to be abandoned. There is very little offence from the sewer-outlets, and a commission of engineers has decided that the bed of the river is not obstructed by the deposits from the sewage.

Leeds, a city of 300,000 inhabitants, has sewers for two-thirds of its population. In 1871 they were served with an injunction obliging them to cease extending their sewerage-system any farther until they purified the sewage before discharging it into the river Aire. They have tried the various precipitating processes, and are now using the A. B. C. in a modified form. The cost of their precipitating works has been £90,000, and their yearly expenses for working them amount to £15,000. The sewers are treely ventilated by untrapped street-gullies.

Manchester, a city of 4,516 acres, with a population of 356,000, has water-closets for only about 50,000. For the remaining 300,000, ash-closets, privies and cesspools are used, but the latter are fast disappearing. The ash-closets are emptied daily by carts, at a cost four times as great as that of the water-carriage system, and in a manner which is certainly much less inoffensive. The idea of the authorities is that the river Irwell will thus be saved from pollution; but it is already so fouled by manufactories that it would be difficult to say whether the slop-water and streetdrainage do not pollute it so much that the additional discharge from the water-closets would make any difference or not. The better classes— only a few of whom live in the city itself · insist upon having water-closets in their own houses.

Birmingham has an admirable system of sewers, having waterclosets connected with about two-thirds of the houses. At the present time they depend chiefly upon one of the precipitating processes to clarify their sewage; but, owing to its great expense and its failure to purify the sewage, they are trying to secure sufficient land for irrigation. The cost of the works is 13,000 pounds a year, beside the interest on the money invested. The return from the manure sold is trifling.

Bristol. — A long intercepting sewer has been built with its outlet four miles below the city.

The

Glasgow. Water-closets are used in the better parts of the city, and elsewhere ordinary privies or charcoal-closets. sewage of the city is discharged into the Clyde, which has been for nearly twenty years so fouled that people have avoided going up the river in steamboats during the summer. The sewers are not well ventilated, so that the gases ascend to the highest points, where also the best houses are, and are thought to give rise to a certain number of cases of typhoid fever. Typhus is common in the lower districts, where there are no water-closets. In 1868, Messrs. Bateman and Bazalgette, in their report, proposed a main-drainage system to carry the sewage out to sea many miles south of the mouth of the Clyde. Sir John Hankshaw has recently been asked to make a report on the question, and it is not yet decided what is to be done.

Edinburgh has not yet completed sewers for all of the lowest parts of the city, but is contemplating doing so. The sewage of the northern part of the city, which formerly created a great nuisance by its discharge into the river Leith, has been intercepted by a main sewer and carried out into deep water.

Much of the sewage of the other parts of the city is flooded over four irrigation-farms, which are profitable, but the sources of considerable complaint. It is proposed to build another long intercepting sewer on the southern side of the city.

The ventilation of the sewers is deficient, and, as in Glasgow, typhoid fever is observed in the houses of the better class on the high land, at the tops of the sewers. Typhus is not uncommon in the "Cowgate" and "Canongate," where the poorest classes live.

Three inspectors are kept constantly employed looking after house-drains, and compelling house-owners to repair breaks and imperfections.

Dublin has, in the main, good sewers, but their discharge into the river Liffey is a source of so great annoyance that many business men have been obliged to remove their offices from that part of the city. The system of intercepting sewers with two siphons across the Liffey, proposed by Messrs. Bazalgette and Carrick in their report, it is generally supposed will be adopted, at a cost of 500,000 pounds. The sewage is to be discharged at deep water, several miles from the city, and at a point where it can be utilized by irrigation, if it shall be thought necessary or best to do so. The sewers are well flushed, but not thoroughly ventilated, an evil which they mean to correct.

Paris. - The enormous sewers of this city are beautiful specimens of engineering skill; but it is doubtful whether they are as satisfactory in a sanitary point of view as those built upon the principles laid down by English and American engineers. The two intercepting sewers, one with a siphon, under the Seine discharge at points quite below the city. The street refuse passes directly into the sewers through untrapped pipes, the idea being that it can thus be removed more cheaply and with less obstruction to travel and traffic than from the streets. There is always,

therefore, quite a large deposit in the sewer; but it is not allowed to remain long, six hundred and seventy men being constantly employed to remove it. Originally, water-closets were not connected with the sewers, but the rule has been changed with reference to the newer houses, and 1,500 of them now discharge into sewers instead of cesspools. Flushing is provided for by the large quantities of water used daily to wash the streets; and the street-gullies serve as free ventilators.

The irrigation with sewage is unfortunately at present carried out on a very small scale and at considerable pecuniary loss to the city, although the farmers, who pay nothing for the sewage, make some profit.

The telegraph-wires and water-pipes are laid along the tops of the arches of the sewers, many of which really resemble subterranean streets in their size. The only objection to this arrangement is that during the flooding of the sewers by storm-water these pipes could not be readily repaired if injured. The water in the sewers has very seldom been high enough, however, to make any such thing possible. Gas-pipes are laid in the streets, as with us, and not in the sewers, for fear of explosions.

There are two principal sources of water-supply beside the two Artesian wells (which latter yield a very small proportion of the whole quantity used). The water from the Seine and the Dhuis is potable, while that from the Marne is used only for washing streets and such purposes.

Frankfort-on-the-Main. A new system of sewers was begun in 1867, under the distinguished English engineer, Mr. W. Lindley. The old sewers are to be filled up and destroyed. The plans show the highest skill. The mechanical execution is most admirable, and no other large city in Europe is so perfectly sewered. The sewage is discharged in the middle of the river Main, under water, and at some distance below the city. The sewers are put at great depth in order to drain the soil, and to take advantage of the ground water for flushing. The street-gullies are all trapped, and no dust or sand is allowed to get in from that source.

Flushing is secured by means of three hundred flushing-gates in the course of the sewers, which are closed long enough to get sufficient head, and then suddenly opened. Ventilation is to be got by soil-pipes carried through the roofs, by rain-water pipes, and by three high ventilating towers, one of which is the chimney of a manufactory. The river is so broad and rapid that it is not likely to be seriously contaminated for some years. Nevertheless part of the original plan provides for sewage irrigation, and the present outlet is therefore placed near land suitable for that purpose.

Hamburg was the first city which had a complete systematic sewerage-system throughout according to modern ideas. How far that was in advance of the rest of the world, in 1843, when the work was undertaken, may be inferred from the fact that there are no real advances in new principles from that time up to the present day. The sewers, unlike those of Frankfort, are made on the “ open system,” that is, the rain-water spouts are all untrapped to serve as ventilators to the sewers; the street-gullies are also without traps, and