Annual report of the Medical Officer of Health / City Council of Pretoria.

  • Pretoria (South Africa). Health Department.
Date:
[1927]
Catalogue details

Licence: Public Domain Mark

Credit: Annual report of the Medical Officer of Health / City Council of Pretoria. Source: Wellcome Collection.

    25/52 (page 21)
    Refuse Removal Service:— The system of collection remains the same. About 170 tons were collected daily. Of this some 150 tons were dumped at various places on the town lands and outskirts of the town. About 20 tons were dealt with by the pulveriser. The cost of collection is 2/8d. per ton. It has not been possible so far to estimate the cost of pulverising. After pulverisation the product is sold at 6/3d. per ton including cartage. Manure Removal Service:— There has been no alteration in arrangements with regard to collection and disposal of manure. The service is carried out without char ge from 200 premises. The amount dealt with was 5,500 tons. The total cost of collection amounted to £1,350 for the year whilst revenue from sale of manure and fertiliser produced at pulverisor amounted to £408. SEWAGE DISPOSAL WORKS. The Manager (Mr. M. Lundie) reports as follows:— Volume of Sewage.—The volume of sewage delivered at the works for the year amounted to 507,334,000 gallons. The maximum volume for 24 hours was 2,451,000 gallons on the 27th February, 1927 and the minimum 821,000 gallons on the 27th January 1927. The daily average for the year amounts to 1,389,945 gallons. The maximum monthly flow was 49,234,000 gallons in November 1926 equivalent to a daily average of 1,641,133 gallons. The minimum monthly flow was 31,931,000 gallons in De¬ cember 1926 equivalent to a daily average of 1,030,032 gallons. Volume of Water over Daspoort Weir.—This represents water from Aapies, Steenhoven and Skinner Spruits together with effluent from the works. The total volume registered for the year amounted to 1946,720,560 gallons which is equivalent to a daily average throughout the year of 5,333,480 gallons. The maximum monthly flow was 271,917,072 gallons in Feb¬ ruary equal to a daily average of 9,711,324 gallons. The minimum monthly flow was 89,936,280 gallons in June equal to a daily average of 2,997,876 gallons. The maximum daily flow was 63,471,000 gallons on the 25th November. The minimum daily flow was 1,258,000 gallons on the 2nd July. The above figures show a considerable drop when compared with last year (admittedly also a dry year). The drop becomes more pronounced when comparisonTs made with previous more or less normal years. ] The averages and ratios of dilution therefore compare very unfavourably with pre¬ vious years. Ratio of Dilution of Effluent to Stream Water at Daspoort Weir:—The maximum ratio of dilution of effluent to stream water was 1 :6.2 in February. Tbe minimum ratio of dilution of effluent to stream water was 1:1.6 in June. The mean ratio of dilution of effluent to stream water for the year was 1 -.2.8. Rate of Filtration:—The average rate of filtration by the 16 circular filters was 155.4 gallons per square yard per diem or 77.7 gallons per cubic yard per diem. Under working conditions with one filter in every set of four as a standby the rate then becomes 207.2 gallons per square yard per diem or 103.6 gallons per cubic yard per diem. Rainfall.—The total rainfall registered at the works for the year amounted to 18.49 inches, this being half the total registered for the year ending June 20th 1925. The max¬ imum fall was 5.77 inches in November. No rainfall being registered for five months in July, August, April, May, June. This abnormal dry season naturally had a very depress¬ ing effect on the quality and yields of farm crops.