1.Settling velocity increases with

2.The type of sewer which is suitable for both combined and separate system is

3.Laying of sewers is usually done with the help of

4.In a BOD test, 1.0 ml of raw sewage was diluted to 100 ml and the dissolved oxygen concentration of diluted sample at the beginning was 6 ppm and it was 4 ppm at the end of 5 day incubation at 20�C. The BOD of raw sewage will be

5.Dissolved oxygen in streams is