TRANSACTIONS OF SECTION G. 881 



almost the whole of the soot was removed and a considerable proportion of the 

 sulphurous acid. 



It may be mentioned that the apparatus is exceedingly ^^imple to work, bein" 

 in fact almost automatic. 



6. The London Sewage Q^iestion. By Cbawfokd Barlow, B.A., M.I.G.E. 



The following obaervations and suggestions are made on the assumption that 

 the recommendations of the joint report of Sir B. Baker and Mr. Binnie are car- 

 ried out. This report advises that two new intercepting sewers shall be con- 

 structed, one north and the other south of the Thames, which are to discharo-e at 

 the present outfalls ; and it suggests that a decision in respect to the question of 

 disposal shall be postponed until the present arrangements have been tested. 



A considerable reduction of the difficulties will be effected if the volume of the 

 liquid to be dealt with is reduced, say, by conveying some of the rain direct to the 

 river. Suggestions of somewhat similar character have been alreadv considered 

 and condemned on account of the great cost and interference with private property, 

 but an arrangement whereby a partial separation of rain from sewage (to be 

 accomplished by conducting the rain off roads, open spaces, squares, parks, public 

 buildings, &c., direct to the river) would, while being effective, avoid these objec- 

 tions. 



There are certain old sewers which were constructed in times past in the 

 valleys and hollows, and were made of large dimensions, so as to be able to convey 

 the flood waters to the river before the main drainage system was designed. 



Five of these — the Eanelagh, the King's Scholars Pond, and the Fleet on the 

 north side of the Thames, the Falcon and the Eflra on the south — are capable of 

 discharging large volumes of liquid, and, in fact, are the ones which now chiefly 

 relieve the main drains in times of heavy rains. 



To utilise these for carrying off ram water only, intercepting sewers could be 

 constructed on each side of them, to be connected with the nearest main drainage 

 sewers, and the rainfall from all the neighbouring streets could be conveyed by 

 small conduits into these great carriers, and so direct to the river. Also new con- 

 duits could be constructed for taking off rain water only to the river. 



The great advantage of such an arrangement is, that the liquid so conveyed 

 would involve no further expense, whereas if the same liquid were conveyed by 

 intercepting sewers to the outfalls it would, in consequence of its mixture with 

 sewage, have to be chemically treated, and the resulting sludge removed. 



The main objection to the present system is the discharge of sewage into the 

 river — either by storm overflows or in the form of effluent or sludge. 



The diy weather quantity of sewage is given at the present time as 180,000,000 

 gallons per diem, but when the proposed new intercepting drains are completed the 

 total amount of sewage discharge at Barking and Crossness will be close upon 

 300,000,000 gaUous per diem, and the resulting effluent must produce most dis- 

 astrous results to the river for miles on each side of the outfalls. 



The amount of sludge is at the present time 40,000 tons per week, but when 

 these new arrangements come into operation it will be increased to 70,000 tons (of 

 which 7,000 tons is absolutely solid matter), and the deposition of this amidst the 

 sandbanks at the mouth of the Thames will most assuredly affect the width, depth, 

 and position of the navigable channels there, and thereby cause obstruction to the 

 navigation, with the great probability of deposits of sewage mud being formed on 

 all the shoals and shores in the neighbourhood. 



In dealing with this question neither Londoners nor the many other persons who 

 are interested in the sanitary condition of the river shotild pennit the London County 

 Council to depart in any way from the recommendations of the lloyal Commission 

 of 1884, that is to say, that they shall not allow them to discharge any effluent 

 into the river nearer London than Hole Haven, or to deposit sludge anywhere ex- 

 cept in the open sea ; and as these conditions will involve an enormous expense 

 fresh considerations should be given to a land treatment, especially as Berlin, 



1892. 3 L 



