The rate of Alteration of pressure filters is A. Less than that of slow sand filters B. In between the filtration rate of slow sand filters and rapid sand filters C. Greater than that of rapid sand filters D. Equal to that of slow sand filters

The correct answer is: B. In between the filtration rate of slow sand filters and rapid sand filters

Slow sand filters have a filtration rate of 0.1-0.2 gpm/ft2, while rapid sand filters have a filtration rate of 2-10 gpm/ft2. Pressure filters have a filtration rate of 1-5 gpm/ft2, which is in between the filtration rates of slow sand filters and rapid sand filters.

Slow sand filters are the simplest type of filter and are made up of a bed of sand that is 2-4 feet deep. The sand bed is slowly washed with water, which removes particles from the water. Slow sand filters are effective at removing particles, but they require a lot of space and time to operate.

Rapid sand filters are more efficient than slow sand filters and can be operated at higher flow rates. Rapid sand filters are made up of a bed of sand that is 1-2 feet deep. The sand bed is washed with water at a high rate, which removes particles from the water. Rapid sand filters are effective at removing particles and can be operated in a smaller space than slow sand filters.

Pressure filters are the most efficient type of filter and can be operated at the highest flow rates. Pressure filters are made up of a bed of sand that is 0.5-1 foot deep. The sand bed is washed with water at a high rate, which removes particles from the water. Pressure filters are effective at removing particles and can be operated in a very small space.