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New Zealand Times, Volume XXXII, Issue 4977, 6 March 1877, Page 2

, In the present discussion on Mr. Climie’s 1 proposals for disposing of the sewage of , Wellington, it will be interesting to note what conclusions on the general question as to the best mode of disposing of sewage some of the best practical authorities in England have arrived at. In an issue of the Manchester Guardian we find an article, from which we learn that in June, 1875, the Local Government Board of Great Britain appointed a committee to enquire into the “ practical efficiency of i the chief systems for the disposal of sewage now in operation, and for which loans have been sanctioned by them.” i The appointment of the committee was caused, as our English contemporary states, by. the fact that the Board had become impressed by the great difficulties experienced by urban sanitary authorities in disposing of the sewage of their districts. Special instructions were issued to the committee to investigate the following systems :-r—l. Sewage farms. 2. Land filtration. 3. Precipitation by chemical process. In connection with these .modes of disposal the committee ■were instructed to ascertain the nature, character, and cost. of the works; the population which the works served, and .the time they had been in operation ; their efficiency, and the degree of purification and deodorisation of the effluent water ; whether any nuisance existed now or formerly from the works; and the yearly cost of maintaining and using them. With regard to sew.ige farms, the committee were to regard their area, soil, and crops, and the financial outcome. In other cases the money realised by the sale of sewage was to be shown. The committee visited sewage irrigation works at Edinburgh, Chorley, Blackburn, Doncaster, Wolverhampton, . Warwick, Bedford, Croydon, Aldershot, Tunbridge Wells, Merthyr Tydvil, Barking, Norwich, and nine other towns. The downward intermittent principle they saw in, operation at Kendal. At Leeds, Bolton, ; Coventry, Tottenham, Edmonton, and Hertford the chemical process was investigated. Bradford, Birmingham, * and Luton, whore sewage sludge is precipitated by the addition of lime, came also within their inquiry. The towns where the “pail system ” is in partial operation, and which furnished evidence, were Halifax llochdale, Salford, and Manchester. Having inspected sewage works of one kind and the other in thirty-seven English and Welsh towns, the committee went to Leyden and Amsterdam, where the “pneumatic system ” is particularly in operation ;■ to Paris, where part of the sewage is employed for irrigation ; also to Brussels and Berlin, where sewage is about to be utilised in husbandry. It will be seen by the above that the report of the committee is necessarily of great interest here, in view of Mr. Climib’s proposals, which, with Mr. Ckawfoed’s. readiness, to use the sewage on his farm, makes the manner in which it is contemplated to dispose of the sewage of Wellington come’ directly under such criticism as the report of the committee aforesaid offers. The committee then, after the ample investigations which as is evident they made, .came to. nine conclusions, as follows “ That the scavengeingj arid cleairising Of towns are necessary for ,comfort and health ; and that in all cases these operations involve questions of how to remove the refuse of towns, in the safest manner and at the least expense to the ratepayer. That the retention for any lengthened period of refuse and excreta in privy cesspits, or in cesspools, or at stables, cowsheds, slaugh-ter-houses, or other places in the midst of towns, must be utterly condemned ; and that none of the (so-called) dry-earth or pail systems of improved privies can bo approved, other than as palliative for cesspit middens, because the excreta is liable to be a nuisance during the period of its retention and the cause of nuisance in its removal; and, moreover, when re-

moved leaves the crude sewage, unless otherwise dealt with- by the filtration through land, to pollute any watercourse or river into which such sewage may flow. We huve no desire, however, to condemn the dry-earth or pail system for detached houses,' or for public institutions in the country, or for villages, provided the system adopted, is carefully carried out. That the sewering of towns and the drainage of houses must be considered a prune necessity under all conditions and circumstances, so that the subsoil water may be lowered in wet districts, and may be preserved from pollution, and that waste water may be removed from houses without delay 1 ; and that the surface and the channels of streets, yards, and courts may be preserved clean. That most of

the rivers and streams are polluted by a discharge into them of crude sewage, which practice is highly objectionable. That, as far as we have been able to ascertain, none of the existing modes of treating town sewage by deposition and by chemicals in tanks appears to effect much change beyond the separation of the solids and the clarification of the liquid.. That the treatment of sewage in this manner, however, effects a considerable improvement, and when carried to its greatest perfection may in some cases be accepted. That, so far as our examinations extend, none of the manufactured manures made by manipulating town’s refuse, with or without chemicals, pay the contingent costs of such modes of treatment; neither has any mode of dealing separately with excreta so as to defray the cost of collection and preparation by a sale of the manure been brought under our notice. That town sewage can best and most cheaply be disposed of by the process of land irrigation for agricultural purposes where local conditions are favorable to its application, but that the chemical value of the sewage is greatly reduced to the farmer by the fact that it must be disposed of day by day throughout the entire year, and that its volume is generally greatest when it is of the least service to the land. That land irrigation is not practicable in all cases, and therefore other modes of dealing with sewage must be allowed. That towns situate on the sea coast or on tidal estuaries may be allowed to turn sewage into the sea or estuary below the line of low water, provided no nuisance is caused ; and that such mode of getting rid of sewage may be allowed and justified on the score of economy.” The report of the committee, according to the Guardian, is a most extensive one, but so far as the plan proposed for Wellington is concerned, it is pretty decisive on one point, as may be gathered from the following resumS of it, published by the Guardian : —“The report opens with a description of the modifications in its volume and constituent elements that sewage undergoes, according to the meteorological and geological conditions, the amount of traffic, the character of the streets and roads, and the nature and efficiency of the sewerage works of the locality. Then there is the difference —and this is very material—between the value the chemist assigns to town sewage and that at which the farmer appraises it. The great difficulty with the farmer is that the sewage must be delivered on his land daily ; but he cannot use it daily, therefore it accumulates. With respect to manure made from town sewage and refuse and ‘ solid manipulated manure,’ the committee have not met with ‘ a single case where it is sold at a profit.’ But they found cumbering the works great accumulations of manufactured manure ‘ several thousands of tons’—at nominal prices which could not be realised. Town scavenging, sewering, and house draining are then considered. It is pointed out that sanitary progress in Great Britain dates from a very recent period. Among other instances they adduce that of Windsor Castle, which in 1850 had within the basement fifty-three cesspools ‘ all full and overflowing.’ The proportion of sewage to excreta by volume and weight is an all-important question to the farmer. Sewage, it is observed, is not profitable to the extent estimated. ‘ln 100 tons (240,000 gallons) of sewage, having the equivalent of eight grains of ammonia to the gallon, the ingredients, are estimated as having a manorial value of 17s. 7d.’ The Rochdale pail system does not produce a manure ‘of sufficient value to repay the contingent expenses and command a ready sale-. ’ • Sewage for irrigation should not be kept in cesspools. The next section treats of ‘ water as a purifier, a cleanser, a dissolver, and a mechanical power.’ This part of the report closes with some general remarks on sewage. That sewage irrigation is not injurious to health is then supported by the experience of Edinburgh and the sewage meadows there, which have now taken the refuse for about 200 years, with no demonstrable injury to the adjacent population. The money return from sewage is naturally contingent on local conditions. Commercially, the sewage manure business is a failure. ‘At Leeds, Bradford, Bolton, and Coventry ’ Messrs. Rawlinson and Read report that ‘ thousands of tons of extracted sewage sludge remain to cumber the works.’ Then the pneumatic or the Liernur system, ‘ one of the most complicated. and costly processes’ known for dealing with solid excreta from dwellings, is described and criticised. Town sewage, its treatment and characteristics, follows. We are told that no chemical process ‘ has ever restored sewage water to its original purity. Though most of the suspended solids may have been removed, the salts of sewage remain.’ The dangers arising to the public health from foul sewers and tanks are animadverted on, as well as the careless cleansing of sewers during periods of sickness. The rent of land for sewage farms, examples of irrigation, the area dependent on local supply, and the kind of crops, are all important points practically investigated. Sections on drains and water-closets, on the clarification of sewage in tanks, and 1 details as to irrigation by town sewage’ close this valuable and unique report.”