A CITY WHICH DRINKS FROM THE SEWAGE.

Wairarapa Daily Times, Volume XXVIII, Issue 7826, 19 August 1904, Page 2

A CITY WHICH DRINKS FROM THE SEWAGE.

[By John W. Corcoran.] The sewage of the city of Berlin, Germany, is disposed of by conveying tbe liquid matter through a system of " canalization " from the city proper to remote districts, 0119 upon the north and the other upon the south side of the city. The sewage farm upon the north is called Blandenburg, and the other Mallowe. B.'andenburg, the larger, lies about eight miles from the city, and consists of low, flat lands. Technically, I believe, the system is called irrigation, as distinguished from the system employed in the United States, which is called filtration, though I confess it is difficult to determine from observation any great difference between the two.

The German plan consists in depositing the sewage upon its farm, discharg- , it at various points so as to make the m distribution equal and uniform. At ' various points wells or reservoirs are established, and by the use of a simple wooden appliance the sewage is held or discharged, as tbe management of the farm requires. Sewage beds in the sense that they are understood in the Massachusetts filtration system are not prepared. Tho contents of the little reserviors just referred to are spread by gravity over small sewage fields, tbe surfaces of which are practically as nature left them. Vegetables, fruit trees, shrubs and things of similar growth assist in taking up the sewage by natural processes, and the earth does the rest by absorption, the air and atmosphere assisting. Tho organic matter is thus discharged in vegetable growth, and the liquid is carried off through the pores of the earth. The farm is a garden of all the beautiful things that nature produces, and the products sold on the provision counters of the city. The interesting feature of this particular farm is that the effluent or resulting water is so purified that it is collected in a reservoir and pumped thence back to Ber]in,to replenish the domestic water supply. Sanitary engineers advise alternate use of these filtration beds, for the purpose, among others, as is stated, of giving the beds " a rest." upon the theory that they will do better work 'f used only intermittently. The same results are in a measure sought here under our scheme of filtration. The striking difference is that under the latter method of sewage disposal, beds have to be made into which the sewage is driven by pressure or gravity; these beds are made of sandy material and constructsd in layers, the coarsest of which is at the bottom and the finest on the top. This arrangement of material is made for the purpose of filtering the sewage. It ought to be said in this connection that the coarser and heavier material in the sewage is taken out in the settling basin at the pumping station, so that the filter beds have to deal with the lighter liquid matter in the sewage. It must be added, to be accurate, that some heavier matter finds its way to the sewage beds; this is taken up by raking it off after the sewage bed dries, or by the vegetable growth, sometimes natural, and sometimes obtained by planting, as at Brockton, Massachusetts. Effluent from these filtration beds is said to be chemically pure, and fit for domestic use. In Clinton, Massachusetts, no attempt is made to return the purified water to the water system, simply because it comes out at a point too low to secure it by gravity and there is no necessity to secure it by pumping. The American system, it would seem, is the more elaborate, and perhaps the more effective. However, I could learn of no complaint in Berlin as to the sufficiency and effectiveness of its system.

Note—The efficacy of thorough filtration, such as Amerisan cities practice upon river water is here strikingly demonstrated. Filtration in this way is said by bacteriologists to remove about 99 per cent, of the disease germs from sewage ; the remaining 1 per cent, diffused through the water supply of a great city is believed to be harmless.