THE TREATMENT OF SEWAGE AND TOWN REFUSE.

New Zealand Herald, Volume XXIV, Issue 7840, 8 January 1887, Page 3

THE TREATMENT OF SEWAGE AND TOWN REFUSE.

Aw Auokland gentleman, who is at present in England, sends a copy of the Western Morning News to show how Southampton has dealt with the sewage and town refuse, in the hope that the city authorities here may endeavour to do something of the same kind. We quote a portion of the article :—

"For many years Southampton has been vexed with the accumulation of Its refuse, and the nuisance created by the discharge of its sewage. It treasured up at a spot called Ghapel, a gruesome and always growing mound of the offscourings of the dustbins, which offended the noses and endangered the health of the inhabitants and it turned into the river from the sewers a stream of filth which nauseated the visitors afloat and befouled the waters to which the town owes its prosperity. The Corporation, assisted by a prescient and practical engineer, determined to rid itself of these unsanitary conditions, and by one bold and comprehensive scheme it has resolved its "burning question" into a question of burning, and seen all its troubles vanish in smoke—and clinkers.

The scheme is very simple, and not, con* sidering its beneficent results, expensive. The refuse collected at Southampton amount* on an average to forty tons a day, and two or three years ago this mountain of " matter in the wrong place" measured upwards of 3000 tons. The outbreak of cholera at Toulon and its subsequent ravages in Southern Europe acted as the vis inertias, aad a depu* tation of the Town Council having visited Leeds, Nottingham, and London, and obtained information on the subject from » number of other large towns, unanimously recommended that body to adopt Fryer's patent destructors. This apparatus consists of six cells or furnaces, each capable of consuming by fire, without the addition of any other fuel, about seven and eight tons of garbage per day, and it is now in full working order. As the collecting carts arrive at the works they pass up an inclined roadway and discharge their eontents directly into the furnaces. The fumes and gases are rendered innoxious and innocuous by their passage through a series of arches, which are the essential principle of Fryer's patent, and are then discharged through a shaft 160 feet in- height. This was one half of the difficulty surmounted, and next came the problem how to deal with the sewage. It was in combining the two objects that the ingenuity of Mr. Bennett, the borough engineer, was brought into play.

Originally the contents of certain sewers, amounting to 500,000 gallons in twenty-four hours, were discharged into two tanks at a spot locally known as the platform, and thence at low tide were emptied into the sea. The result was that the waters were polluted in a manner which threatened to destroy Southampton's reputation as a yachting resort, and > the intermittent disoharge periodically scaled up the sewers and drove the gases and emanations into the homes of the inhabitants. Mr. Bennett, after a careful study of the subject, resolved to teak what is termed patent) porous carbon, a discovery of Mr. Ellis, and the property now of the Patent Porous Carbon Company, whose works are at Newton Abbot. The product satisfied all Mr. Bennett's requirements and the treatment is as simple as it is effectual. About one hundred yards from the juuetion of the sewer with the two reservoirs referred to is a small tank, in which the porous carbon is mixed with water. From this receptacle it runs into the sewer, and falling over a small weir, becomes thoroughly incorporated with the sewage. When one reservoir is full the contents are allowed to remain quiescent while the precipitating action is going on, and in the meantime the drain is tamed into the tank adjoining. In about two and a half hours the solids, acted upon by the oxidising and highly carbonaceous material which tha Carbon Company supplies, sink to the bottom in the form of sludge, and the effluent or liquid, which is praotically colourless quite inodorous, and gives no action upon litmus paper, is drained off into the sea. This is accomplished by an ingenious arrangement known as Shone's pneumatlo ejector. In each tank is a buoy, and shackled to it Is a movable pipe, the end of which is always a few inches below the surface of the effluent The harmless liquid escapes through this pipe until the buoy rests upon the bottom of the reservoir, where the mouth of the arm is held a short distance above the sludge. This resultant is now about the consistency of treacle, but the chemical action of the porous carbon has rendered it to a large extent deodorous and inocuous, and capable of being dried by natural evaporation in the open air, or still mora rapidly by heat or pressure. What is to become of it? At Southampton, where the scheme has been in operation thirteen months, every particfe produced has been mixed with road sweepings, and sold to the farmers of the district for manurial, purposes at 2s6dper load, - and the demand still exceeds the supply. In order to guard against any accumulations under altered circumstances in the future, Mr. Bennett conducted further experiments, and found that the sludge when discharged directly into the cells of Fryer's destructor, could be consumed with the refuse without danger or annoyance. To obviate the expense of cartage from the. platform to the destructor, the ingenious engineer laid a sealed main, and the deposit is now forced in a continuous stream from the reservoirs to the sanitary works— about a mile distant—by compressed air, the energy being generated in a multitubular boiler heated by the burning waste and refuse of the town. The slag or clinker which the furnaces emit is utilised is the foundation of new roads, and in reclaiming a valuable piece of land from the sea, and a fine white ash, 'another resultant from the process, is invaluable in the prepatation of mortar. The prime cost of the destructor was about £3600, and the sewage portion of the works £2SOO. The current outlay is 7a 6d a day expended in porous carbon, the wages of a man to mix it with the sewage and four stokers ; and Mr. Bennett is now devising an automatic mixer to be worked by the boiler in the destructors, which will relieve the town of the cost of one labourer. Against all this the Corporation have to set the income from the sale of sludge, an appreciably dimished death rate, and the removal of a fruitful source of danger and annoyance.