Microphotograph of water in the sump after 7 days
Once the oil is broken down into smaller droplets, bacteria consume the oil. TPH of the oil in the wash water on the day of treatment was 286 ppm with a large population of bacteria along with the oil droplets. However, on 7th day another sample was collected and interestingly this was water was very clear. Under microscope, the population of bacteria was much less than on the start day and the TPH of the water was 25.6 ppm thus suggesting that once the oil is consumed, bacteria die a natural death. One more significant observation was that there was a sudden increase in protozoan population in this water and this was attributed to the reduced toxicity of the water in the sump. These protozoans were transferred into a culture medium to facilitate the growth of the population and in one set the protozoan were fed with SpillRemed and one could see that the population of these ciliates was actually feeding on the bacteria and thus in a water which did not allow healthy growth of protozoans, there was now an establishment of a food chain.The results answered an important question of what happens to the bacteria after the oil is consumed:; they either die a natural death in the absence of any available food or predators consume these bacteria.