WATER SUPPLY.
The Report, by Professor Frankland, on the analysis of the waters supplied by the Metropolitan Water Companies during the several months of the year, is, on the whole, somewhat more favourable than usual. As regards “temperature,” he notices the wide variation in the waters derived from riverian sources, as compared with the narrow range in the deep well water of the Kent Company, derived from the chalk. The temperature of the Thames water varied from 36° Fahr. in February to 68°–9 in June, a range of 34°; while the range in the water of the Kent Company was only 7°–9 Fahr., viz., from 51–l° in May to 59° in September and October. The total solid impurities—composed of a great variety of substances, some of which are organic and very objectionable, and at times eminently noxious, while others are either entirely or comparatively harmless—was rather less than in previous years, the progressive increase in the quantity which had been noticed during the years 1871–2–3 having apparently ceased. The maximum was observed in January, and the minimum in July. The character of the Thames water, in respect of organic impurity—as represented by its two most important constituents, carbon and nitrogen—was practically the same as in the previous years. The maximum pollution occurred in March, April, and December, when the river was in a very objectionable condition. In December the Chelsea Company supplied this foul water in an unfiltered condition, and contaminated with fœcal matter. The subjoined table shows the maximum, minimum, and average quantity of organic matter in the water, the amount of organic element (organic carbon and organic nitrogen) in the Kent Company’s water being taken as unity, or the standard of comparison:—
| Name of Company. | Maximum. | Minimum. | Average. |
| Kent | 1.0 | 1.0 | 1.0 |
| West Middlesex | 4.3 | 2.0 | 3.0 |
| Grand Junction | 4.9 | 2.4 | 3.3 |
| Chelsea | 7.1 | 2.3 | 3.7 |
Professor Frankland remarks that the water of the Thames is at its source as free from pollution as the chalk well water, but on its downward course becomes largely and progressively contaminated by sewage and the washings of cultivated land, especially during winter.
The average hardness of the Thames water—or the weight of carbonate of lime, or its equivalent of other soap-destroying substances, found in 100,000 parts of water was 21° or parts in 1873, and 19.7° in 1874. Large quantities of soap or soda are required to soften the water before it is used for washing; but this process could be accomplished for a small portion of the expense by substituting lime for soap or soda, as practised on similar waters at Aylesbury, Canterbury, Caterham, and Tring. The following table exhibits the degree of efficiency of filtration of the waters:—
| Name of Company. | No. of occasions when clear and transparent. | No. of occasions when slightly turbid. | No. of occasions when turbid. | No. of occasions when very turbid. |
| Chelsea | 6 | 5 | 0 | 2 |
| West Middlesex | 12 | 1 | 0 | 0 |
| Grand Junction | 7 | 5 | 1 | 0 |
The exceptional occasion on which the water supplied by the West Middlesex Company was slightly turbid was in December, when the condition of the Thames was bad for a lengthened time, so that even the large storage of the Company proved insufficient to render them independent of flood water; it being impossible, moreover, to separate by filtration the whole of the finely divided clay to which the turbidity of the water was due. The Kent Company’s deep well water, having already undergone natural filtration through an enormous thickness of chalk, is always clear and transparent, without artificial filtration. The appliances of the Companies supplying river water are, excepting in the case of the West Middlesex Company, unequal to the filtration work required of them. The microscope is called into use in the examination of potable water, and it always reveals numbers of living and moving organisms in the sediment deposited by turbid water on standing. The annexed table exhibits the results of such microscopic examinations during the past six years:—
Name of Company. | Number of occasionswhen living | |||||
1869. | 1870. | 1871. | 1872. | 1873. | 1874. | |
Chelsea | 3 | 2 | 2 | 3 | 2 | 5 |
West Middlesex | 0 | 0 | 0 | 0 | 0 | 0 |
Grand Junction | 4 | 1 | 1 | 2 | 3 | 5 |
To Professor Frankland’s valuable report, the main features of which I have thus summarised, are appended numerous tables setting forth, in detail, the various information condensed in the text. I subjoin, as of greatest general interest, Table M, which exhibits the
Averages for 1874.
(The numbers in this Table relate to 100,000 parts of each Water.)
Names of Companies. | Temperature in CentigradeDegrees. | Total Solid Impurity. | Organic Carbon. | Organic Nitrogen. | Ammonia. | Nitrogen, as Nitrates andNitrites. | Total Combined Nitrogen. | Previous Sewage or AnimalContamination. (Estimated.) | Chlorine. | Total Hardness. | Proportionate Amount of organicElements, that in the Kent Company’s Water being taken as1. |
Thames. | |||||||||||
Chelsea | 11.8 | 26.46 | .211 | .039 | .001 | .155 | .196 | 1250 | 1.87 | 19.3 | 3.7 |
West Middlesex | 12 5 | 26.62 | .176 | .028 | .001 | .124 | .153 | 930 | 1.83 | 19 4 | 3.0 |
Southwark | 12.7 | 26.68 | .192 | .030 | .001 | .125 | .155 | 940 | 1.83 | 20.0 | 3.3 |
Grand Junction | 11. 4 | 27.00 | .186 | .033 | .001 | .129 | .164 | 990 | 1.83 | 20 0 | 3.3 |
Lambeth | 12.0 | 27.88 | .196 | .037 | .001 | .144 | .181 | 1120 | 1.87 | 20.0 | 3.4 |
Other Sources. | |||||||||||
New River | 12.2 | 26.02 | .087 | .015 | .001 | .146 | .162 | 1150 | 1.67 | 20.1 | 1.5 |
East London | 11.8 | 27.13 | .153 | .027 | .001 | .076 | .104 | 560 | 2.04 | 19.3 | 27 |
Kent | 12.4 | 40.36 | .057 | .012 | .000 | .371 | .383 | 3 40 | 2.48 | 28.1 | 1.0 |
But it is not to Professor Frankland alone that we are now indebted for information respecting the water we drink, many very interesting facts being supplied by Major Bolton, R.E., the water examiner appointed by the Board of Trade, under the provisions of the Metropolis Water Act, 1871. Major Bolton’s reports, which, by his courtesy, I receive every month, afford information on all points relative to the machinery for water supply, and to the provisions already made, or in progress, for giving a constant supply, the main object of the Act; and which, I suppose, we may, at some remote future, hope to obtain. As the information in question is not generally accessible, I make no apology for presenting a resumé of it on this occasion. And, first, with respect to the constant service, we learn that the West Middlesex Company are giving constant supply to a number of houses, on the application of the owners, and are fully prepared to extend the supply when called upon. Extensive works and additional engine power of 120 horse power are in course of construction at Hampton.
The Grand Junction Company have formed a high service reservoir near Kilburn, to contain 6,000,000 gallons, for constant service, and are completing the line of main pipes to connect up this reservoir with the works at Campden-hill; they are likewise erecting boilers and works at Hampton, for which place an additional 70-inch engine of 125 horse power is being constructed, and an extra 30-inch main from Hampton to Kew has been ordered to be laid down. The Chelsea Company does not appear to have taken, as yet, any steps in this matter, having, as we shall see, other and more pressing work in hand. The Act of 1871 provides power to compel the companies to give a constant supply as and when the “public authority” may see fit to move. The authority (Metropolitan Board of Works) has not seen fit to move in respect of the companies supplying this parish, nor is it probable that any steps will be taken until the stringency of the water regulations, to which I have already referred, has been modified.
The number of miles of streets in the Metropolis which contain mains constantly charged, and upon which hydrants could at once be fixed, is 666—including 67 in the West Middlesex, 41½ in the Grand Junction, and 50 in the Chelsea Company’s district. The companies are prepared to affix hydrants thereon when required by the authorities; but, in fact—although hydrants might be used for street watering—of 2,531 hydrants already erected, 1,996 are for private purposes, and only 535 for public purposes, including 267 for street watering, in the entire Metropolis.
The companies supplying this parish obtain water exclusively from the Thames, viz., the West Middlesex and Grand Junction Companies at Hampton, and the Chelsea Company at Ditton. The bad state of the water supplied by the last-named company in December appears to have been caused by the intake being “below the filthy outflow of the rivers Mole and Rye.” The total volume which may be supplied daily by each company is 20,000,000 gallons. The average daily supply during the month of December was—West Middlesex, 8,600,000; Grand Junction, 10,200,000; and Chelsea, 7,200,000 gallons—eleven to fourteen per cent. of the water (exclusive of waste, an enormous but unknown quantity!) being delivered for other than domestic purposes. The number of houses supplied in the several districts is—West Middlesex, 46,404; Grand Junction, 35,144; and Chelsea, 28,395. Only 401 houses in the West Middlesex district have a constant supply. The estimated population supplied is—West Middlesex, 348,000; Grand Junction, 316,000; Chelsea, 210,000. The West Middlesex Company possess eleven engines of 1,341 horse power; the Grand Junction, eleven of 1,820 horse power; and Chelsea, eight of 1,025 horse power. The number of miles of mains possessed by these companies in the Metropolis is—West Middlesex, 248; Grand Junction, 200; Chelsea, 170. The West Middlesex Company have three subsiding and storage reservoirs for unfiltered water—area, 20½ acres; available capacity, 57,000,000 gallons: and three covered reservoirs for storing filtered water, of an aggregate capacity of 10,922,000 gallons. This company, by means of its large reservoir capacity, avoids taking in water during floods. The Grand Junction Company have four subsiding and storage reservoirs for unfiltered water—area, 7 acres; available capacity, 19,500,000 gallons: the number of covered reservoirs for filtered water being three, their capacity 18,000,000 gallons. This company requires additional impounding and subsiding reservoirs. The Chelsea Company have no reservoirs for unfiltered water, and only two (capacity, 11,000,000 gallons) for storing filtered water. The filter beds of the several companies are as follows:—West Middlesex, five in number, area 8 acres, depth 5 feet, viz., Harwich sand 1ft. 9in., Barnes sand 1ft., and gravel (screened to different sizes and arranged in layers) 2ft. 3in. The average rate of filtration per square foot of area was, during December, 1½ gallons per hour. (It may be here observed that the quality of the water is improved by a slow rate of filtration—the rate should not exceeded 2½ gallons per square foot of filter bed per hour: this will give 540 gallons per square yard each 24 hours, and at this rate filtration should be effectual.) Grand Junction: Number of filter beds, 4; area in acres, 7¾; depth, 5ft. 6in.—viz., Harwich sand, 2ft. 6in.: Hoggin, 6in.: fine gravel, 9in.: coarse gravel, 9in.: boulders, 1ft.: average rate of filtration, 1⅓ gallons per square foot of area per hour. Chelsea: Filter beds, 7; area, 6¾ acres; depth, 8ft.—viz., Thames sand, 3ft. 3in.: shells, &c., 3in.: gravel, 4ft. 6in.; rate of filtration, 2⅓ gallons per square foot per hour. It will be observed that notwithstanding the greater depth of the filter beds of the Chelsea Company, the water supplied by the Company in all times of difficulty arising from a flooded state of the river is unfit for drinking, although the rate of filtration is slower than that deemed sufficient by the water examiner. This is due to the total absence of impounding and storage reservoirs for unfiltered water, to the exceptionally bad quality of the water taken in by the Company, owing to the improper situation of the intake at Ditton, and to the impossibility of filter beds removing suspended matter when in any large quantity; that, moreover, being a principal object of the subsiding reservoirs. The disgusting condition in which the water of the Company was sent out during parts of the months of November and December formed the subject of many complaints, both in the public press and in communications addressed to myself, and was referred to in my reports, dated December 16th, 1874, and January 13th, 1875. I had, on former occasions, reported specially on the subject, and particularly in February, 1872. The dissatisfaction which the condition of the water at the latter date gave rise to induced the Company to take steps to improve their means of supply by enlarging their storage. The scheme submitted to Parliament in the Session of 1873 included the embanking of the Thames at Hampton Court, and was defeated by a strong public opposition, on what I described at the time as æsthetical grounds. No further attempt appears to have been made by the Company to put their supply on a proper footing until the great outcry referred to arose. On the 18th December, however, at a special meeting of the proprietors, a resolution to the following effect was passed:—
“That the directors be authorised to take such steps as in their judgment may be necessary or expedient to obtain a fresh intake, with reservoirs and other works connected therewith, and lay the necessary main pipes from the site of such proposed intake to the works at Seething Wells, with the least possible delay.”
The measures taken by the directors to secure the land—an area of 50 acres, near Molesey—for the construction of impounding reservoirs, were approved and adopted, and the directors were authorised to apply to Parliament in the now current Session for the necessary powers. This they have done, and there is every probability that their Bill will pass, and that with the completion of the contemplated additions to their works this Company will be able, at no distant time, to supply its customers with water as clear and transparent as any derived from the River Thames.