New Britain herald., 1914-07-09

\ $. | comes from the pickling liquors used l plants in the city.
 Tt is significant to note that there | was no free acid present in the sew age at any time during the investi- gations made last week. Although l the city water supply is unusually soft, it appears that trade wastes con- 1 tain sufficient alkali to neutralize all l of the unused portions of the acid employed as a pickling liquor at the various manufacturing plants All l of the analyses of New Britain sew 1 age that we have examined indicate a high quality of mineral matter dis solved in the sewage
 1 'unquestionably the iron wastes 1 have been an important factor in the l clogging of the existing filters and l have interfered seriously with their l efficient operation. As I understand the situation, the iron wastes for the most part could be kept out of the !. city sewers and treated at three or more plants in the city.
 Keep Trade Wastes Out of Sewer. 1 T consider that it would be highly desirable to keep the trade wastes out
 
 l able. How to proceed to do this is question that I have not investigated 1 sufficiently to warrant a final conclu- sion. But it is perfectly feasible to keep these trade wastes out of the sewers and shall proceed with the balance of this report on the basis ] that the disposal works are to treat l sewage of substantially domestic origin, with trade wastes constituting phase of the problem that will have tc be handled separately either at the manufacturing establishments in the city or in connection with an enlarge ment of the disposal works beyond that required in the absence of these iron wastes.
 "As the sewage reaches the treat ment works, it is allowed to flow dur ing the warmer season of the year di- rectly on to the thirty-two different sewage beds in turn. During the winter the sewage is allowed to first. pass through the settling reservoirs above. mentioned. At the time of my visit the filter beds were seriously overloaded and some of them had not the deposit of sludge at the surface removed since last autumn.
 When these beds were uncovered V oN iron within the pores of the fil- tering material, particularly at, and near the underdrains of the bot tenn of the filters. >
 Tt is during the spring and early summer that odors have been most marked at and near these beds. due to the accumulation of sludge during the winter months. This sludge un- dergoes foul putrefaction long before It can be completely removed from the tanks and filter beds
 The effluent or filtered sewage was fairly cleear as 1t flowed through the ditches to the Mattabessett river at the time of my visit. It was plain. however, from the amount of iron rust on the bottoms and sides of the ditches that the sewage was being merely strained and not subjected to any oxidation worthy of mention. Obviously the sewage beds were grossly overtaxed.
 sand beds of the type here in- stalled for New Britain are ordinarily capable of dealing with unsettled sewage .at rate corresponding to a sewage flow from 500 to 700 people Ter acre of filtrating surfoce. When the sewage is well settled, which is
 
 Britain, and where the Altering ma tcrial is relatively coarse, rates of Alteration nearly double that above mentioned are sometimes feasible. The local material consists of much gravel and relatively coarse sand. but unfortunately there is distributed through it clay and disintegrated shale that seriously restrict the efficiency and capacity of the local filter beds.
 "As above stated, iron wastets and Eickling liquors from the manufac- turing plants in the city are a. serious handicap to the local inter- rnittent sand filters, the rating of which elsewhere at 500 to 700 persons per acre Is based upon unsettled sewage that is substantially free of trade wastes. In this connection will refer. however, for further de- tails to my book on Sewage Disposal pages 720 and 666: and also page 7S of the Practical Methods of Sewage Disposal by Messrs. Ogden and Cleveland.
 Conclusion as to Present Plant.
 "In my Judgment, >the city of New Britain ought to have from 80 to 100 acres of filter beds in order to dispose satisfactorily of the unsettled sewage of the city at the present time inde- pendently of the influence of trade wastes, particularly the iron pickling liquors now entering the sewers and seriously clogging the present beds.
 'The present beds are clogged to a degree which makes them of very little use other. than as mere strain CTS to take out suspended solid mat ters. The cost of repairing them is so great that it will be cheaper to build new filter beds of coarser ma terial which will allow the air to reach the bottom of the beds thus