REPORT OF COMMISSIONER OF FISH AND FISHERIES. 113 



ness in operating, the quality of this waste is inexcusably bad, a large amount of 

 oil and tar escaping with it. 



By weir measurements the amount of waste discharged from the subsidence tank 

 and escaping into the sewers was at the rate of 0.173 cubic feet per second, equal to 

 112,000 gallons per 24 hours, or about 2,150 barrels. It was impracticable to deter- 

 mine the amount of oil and tar contained in this, but the samples show that it must 

 he at the rate of several barrels per day. 



While these works are not now running during the night, it is probable that, 

 except in the summer months, the total discharge for 21 hours is greater than indi- 

 cated above. 



3. Illuminating-gas ivorhs. — The discharge of waste from the works of the Terre 

 Haute Gaslight Company is from a pipe on the bank of the river near the works. It 

 is of much cleaner quality than the preceding. The discharge was at the rate of 

 43,000 gallons per 24 bonis. Of this the oil did not amount to more than a few gal- 

 lons a day. From what could bo seen, I judge that little pollution comes from this 

 source. 



The discharge from the oil wells and the fuel gas works is into the city sewer, 

 known as the canal sewer, which empties into the Wabash Rher at the foot of 

 Eagle street. Samples taken from the sewer at three different points show a strong 

 indication of oil, and even near the outlet, where sewage discharges down an incline 

 with a velocity of 10 feet per second, at the rate of 2,000,000 gallons per day, the oil 

 quickly comes to the top and floats along down the bank. The very marked coating 

 of oil on the Avails of the sewer shows that the discharge of oil must have continued 

 for a considerable time and that it has been at different stages of Ihe river. 



It may be said that the total amount of oil discharged into the river is not large 

 when compared with the oil received by other streams, and that the waste is not 

 relatively as large as that from some oil wells and refineries. However, the refusal 

 of the oil to diffuse with the water makes its presence, even when intermittent, very 

 perceptible, and the results are far different than would be the case with diffusing 

 liquids. 



It is fortunate that this very principle of nondiffusion makes the separation of 

 this refuse from the ordinary washings very easy, and hence the method of avoiding 

 its discharge into the river is simple and inexpensive. The only process needed 

 is that of separation by subsidence, carrying out more thoroughly and completely 

 the method now used, at both the oil wells and the fuel gas works. 



The situation is such that no pumping or extra labor is necessary beyond the 

 watching, the proper drawing off of oil and waste, and the occasional cleaning of the 

 tanks. Contrary to what might be expected, there will be no necessity for expen- 

 sive processes such as are used iu sewage purification works. 



The recommendations I would make relative to the disposition of the refuse are 

 that the oil and tarry waste be not allowed to reach the sewer or the river, and that 

 this waste be separated from the unobjectionable waste water by the process of 

 subsidence in tanks. The difference in specific gravity is so marked that the repa- 

 ration of the water will not be difficult. 



At the oil wells a tank at least 12 feet deep and 16 feet in diameter should be sunk 

 in the ground to such a depth as to catch all overflow from the wells and all leak- 

 age from tanks and pipes and waste from loading. The inlet should be so made 

 that the inflow will not agitate the liquid in the tank. A perforated partition will 

 direct the proper distribution of the liquid. The outlet pipe should project well 

 into the tank 3 or 4 feet above the bottom of the tank and bo so perforated as to 

 obtain an even draft from the liquid without causing any perceptible current iu the 

 tank. It should then be carried to the level of the inlet and connected with the 

 discharge pipe. By this process the water will bo carried away and the oil and 

 heavier matter held in the tank. Care must be taken to draw off the oil and waste 

 at the top as fast as it accumulates and to clean the bottom as often as necessary. 



In drawing off the " B. S. - ' from the steaming tank, sufficient time for the 

 discharge must be given, that the How through the separation tank will be 

 F. R. 94 8 



