The Sewage of South London

Londoners in general arc (says a writer in the P.M. Budget) wonderfully apathetic about matters which concern them closely and which conduce to their health, happiness, and comfort. We turn on a little tap and are at once supplied with abundant light or plenty of water, but little heed is given to the previous deep thought and incessant care which have brought us to this wellarranged state of affairs. Water pipes and gas pipes ramify through every street and lane and alley, distributing their valuable contents to the inhabitants of the dwellings therein. Then there are huge sewer pipes which carry away for us all that is disagreeable and unwholesome. VVe say that eur present supply of gas and water is perfect, nor that our mode of dealing with the disposal of our sewage is perfect, but at all events they are on the high road to perfection. It was one day, a short time ago, when cogitating on the vast machinery requisite to meet the demands of Londoners, and more especially to keep them in a healthy sanitary condition, that I was led to visit the outfall works at Crossness, where the sewage from the south side of London is poured into the Thames. It comes along in a sewer 'llft 6in in diameter. The main pumps lift the sewage into reservoirs, where it is treated chemically with lime and proto-sulphate of iron in the proportion of four grains of lime per gallon and one of proto-sulphate of iron. The sewage in the course of treatment flows along large reservoirs. The flow is very slow, in order that the majority of solids may be deposited. It flows finally over a weir wall, and thence into the river. This is called the effluent. This treatment necessitates the use of fifteen to eighteen tons of lime per day, and four to five tons of proto-sulphate of iron. The sewage is drained off the reservoirs every two days, and men go down and thoroughly clean all the sludge out, which is swept down to a sump, and pumped from there into the sludge-settling channels,where it undergoes a further draining. It is then let down into a lower sludge store, and pumped from there on to ships and taken to sea. Fifteen to twenty thousand tons per week of sludge are sent to sea. There are five sludge ships altogether, which are sent out at every tide. They go some forty miles away. Two engines are required for pumping up the sludge from the reservoirs to the sludge settling channels, and two for pumping the sludge from the sludge store to the ships. There are four precipitation reservoirs, the capacity of two being 6,250,000 gallons each, and that of the two smaller ones 3,125,000 each, or a total precipitation reservoir capacity of 31,250,000 gallons. In the warm weather the effluent is deodorised by means of manganate of soda and sulphuric acid in the proportion of one grain of manganate to .75 gr. of sulphuric acid per gallon of effluent. This deodorising at Crossness costs Londoners just LlOO a day, so that it is not continued longer than absolutely necessary. Crossness Outfall Works employ from 190 to 200 men. They have an engineers’ shop on the spot fitted up to carry out the various repairs that are constantly required to be done. Some strange things get into the sewers of London, and now and again babies have been found. Such are some of the most important features of a section of the great machinery of themetropolis.whichneverrests, never sleeps. Notwithstanding the room

' which exists for further improvement in the disposal of its sewage, the reduction which has been brought about in the death rate of London in modern times is as noteworthy a> it ia satisfactory. In the latter half of the seventeenth century the average mortality of London is said to have been not less than 80 per 1000; at the end of the eighteenth century it had dropped to 50 per 1000; while in 1890 it had fallen to 19-8 per 1000. , ... The main intercepting and principal branch sewers which have been constructed for the conveyance of the sewage of London to the two outfalls into the river Thames at Barking and Crossness respectively measure about 80 English miles. As illustrating the magnitude of London, it has been computed that the streets and roads within the. metro, polis if placedend toend in onecontinuousline, would measure about 2500 miles, equal to the distance from London to Land’s End, thence across the Atlantic Ocean to tho mouth of the Gulf of St. Lawrence in Canada on the west; or going eastward would extend across the entire continent of Europe, and beyond the Ural Mountains into Asia. So one can understand at a glance what it means to control its drainage, water supply, etc. Supposing we were to employ animals to do the work which our engines do for us in pumping water and sewage, we should require four times the number of horses in the entire British army, both at home and abroad. This gives some idea of the labour involved in giving us our water and taking away our sewage.