SEWERAGE OF A SEASIDE TOWN. 



781 



The disposal of the sludge is the most difficult matter to 

 be satisfactorily dealt with in connexion with chemical treat- 

 ment of sewage. Pressing it into dry cakes for sale as 

 manure is a delusion and a snare. The most valuable 

 manurial part of the sludge is still in solution, and the pressing 

 out of the water consequently sends out with it the ammonia 

 and soluble phosphates, and so the remaining cake is not 

 worth the cost of pressing ; and, to complete the folly of the 

 whole proceeding, the concentrated manure in the expressed 

 water is returned to the tanks to be treated over again — that 

 is, to be re-diluted and re-concentrated. At Southampton 

 the sludge used to be burnt in the destructor, but is now 

 mixed with street sweepings and sold readily as manure. At 

 Birmingham the sludge is also profitably utilised by being- 

 spread over land and then dug in. At London it is sent out 

 to deep sea in tank ships. At Ealing it is burnt. At every 

 other place I know it is accumulating and growing to the 

 dimensions of a " serious difficulty." It goes without 

 saying that if there is a market for it as at Southampton, or 

 land for it without expense of carriage, as at Birmingham, 

 the sludge should be utilised ; but as I do not think the one 

 or the other is likely to be oljtained in the colonies in the case 

 of the larger cities, I should in their case recommend the 

 disposal of it by burning it in the destructors that must 

 necessarily be built for scavenging purposes. This can be 

 done without nuisance, as everyone knows who has had any 

 experience with destructors. If it be objected that this is 

 wasting manure, I would reply, Let anyone who ol)jects 

 to the Avaste take the manure and use it. And I would go 

 further, to encourage him to take it — I would give him what 

 it would cost to burn it. It will be understood that with 

 ejectors there is no necessity to place the destructors close to 

 the tanks, but that they can be placed wherever most con- 

 venient in relation to town refuse dis])Osal. 



I have now brought the matter with reference to sewage 

 ti'eatment by ferozone to the same stage that I arrived at 

 with reference to its treatment l^y irrigation, and can thus 

 resume what is necessary for, or commonly incidental to, a 

 system for the disposal of the sewage of a seaside town by 

 this precipitating process : — 



1st. To provide covered tanks sufficiently large to treat 

 the whole sewage. 



2nd. To provide a sufficient quantity of the })recipitant. 



