Engineering Wonders of the World
Volume III

224 ENGINEERING WONDERS OF THE WORLD. sity to lift this water into the Thames. The Lot’s Road station contains eight large cen- trifugal pumps, able to discharge each 3,200 cubic feet (about 19,000 gallons) a minute, rope-driven by twin-cylinder gas engines built on the “ Otto ” principle. Four of the engines develop 260 horse-power; four, 210 horse- power. The more powerful engines pump from the Counter’s Creek sewer, the others from the low-level intercepting sewer, into the Thames. Compressed air is used to charge the pumps with water and start the engines. Twenty to thirty minutes suffice to get all the pumps to work. When steam-power is used at a storm-water pumping station—as in the Isle of Dogs—the fires must be kept banked ready for any emergency, a course which entails heavy expense in fuel; whereas the gas engine is ready to start at a moment’s notice, and costs nothing when not running. Therefore it is improbable that any more steam engines will be installed for dealing with the dis charge of storm water into the river in future. Adjoining the Deptford Creek is the Dept- ford pumping station, in which are six main pumping engines capable of raising 193,000,000 gallons of sewage daily to a height of about 20 feet. At Crossness—where, as we have stated already, all the sewage from the southern district has to be lifted—is the largest of th© pumping installations. Here are six engines, of which, four are beams and two triple-ex- pansion vertical engines. The total pumping capacity of these six engines is 250,000,000 gallons per day. The lift is about 21 feet. Each, of the beam engines has two pump plungers 9 feet in diameter, which, prob- ably makes them the largest pump plungers in the world as regards diameter. | In addition to the stations mentioned above ar© those for dealing with storm water at Heathwall, Nin© Elms Lane, King’s Scholar’s Crossness Pumping Station. Pond, Pimlico, Falcon Brook, Battersea, and Shad Thames, Bermondsey. Plans for a storm-water pumping station at Abbey Mills, capable of raising 150,000 gallons a minute, are in course of preparation. The problem of draining London has indeed been a difficult one to handle, but it has been solved in a most masterly and efficient man- ner. At the beginning of this Figures. century about 5,140,000 people inhabited the area to be drained *—the total has increased considerably since then—a popu- lation equal to that of Glasgow, Liverpool, Manchester, Salford, Leeds, Birmingham, Shef- field, Newcastle-on-Tyne, Bristol, Hull, Dub- lin, Belfast, and Edinburgh combined—or, in other words, to eight times that of Glasgow. Every day of last year an. average volume of nearly 300,000,000 gallons of sewage had to be treated at Barking and Crossness, and all the huge amount of solid matter abstracted and carried out to sea. It is indeed difficult to appreciate the vastness of the work and its maintenance for which the London County Council is responsible in connection with the sewage of the Metropolis. Despite its huge area and population, London, is one of the healthiest cities in the world ; and that this is due largely to the excellent drainage must be apparent from a comparison of the follow- ing death-rate statistics with, the development of the drainage works. Prior to 1874—in which year Sir Joseph Bazalgette’s scheme of intercepting sewers was completed—the average annual death- rate per thousand in the Metro- polis was about 24. During Ettect °* Qood , . .1 Drainage on the decade 1871-80 the figures the Death_ fell to 22’5. The works for Rate, treating sewage chemically and carrying the sludge to sea were completed * This includes, besides the county of London, Acton, Wood Green, Tottenham, West Ham, Penge, and parts of Willesden, Hornsey, East Ham, Croydon, and Beckenham—an area of about 31 square miles. The total area drained is about 150 square miles.