| 摘要 |
<p>The presence of material which would slow growth of bacteria in effluent is detected by measuring the rate of disappearance of dissolved oxygen in a sample which has been oxygenated and inoculated with bacteria. The measurement is made with an electrochemical oxygen meter. The steps in the test are as follows: (A) Measured quantities of effluent, diluent water and bacteria source are charged to separate measuring tanks. They are held at the required temp. and air is bubbled through all the tanks for a predetermined time. (b) The diluent and bacteria source are run into a stirred fermentor at the same constant temp. and air is bubbled through the mixt. for a predetermined time. (c) The effluent is run into the fermentor. The air supply is stopped and the vessel is sealed from the atmos. The amts. of effluent and diluent are chosen so that the bacteria added are sufficient for the bacterial activity can reach its maximum value. The oxygen and demand is greater than the total oxygen available in the fermentor. The rate of oxygen used is small enough for equlibrium to be maintained between the liq. and gas phases in the fermentor. A meter is used to determine either the fall in oxygen concn. in the liquid in a given time or the time taken for a given concentration drop. The average rate of oxygen use is calculated. The actual rate is compared with that for a similar procedure with a poison free nutrient substrate replacing the effluent. The method is sensitive to small amts. and takes only a few mins. to give a result.</p> |
