The filter material used in contact bed is
Explanation: The filter material used in contact bed is broken stones called as stone ballast.
Which of the following is called as contact bed?
Explanation: Contact filters are water tight tanks which are used for the aerobic treatment of sewage. They are also called as contact bed.
How many types of trickling filters are used in sewage treatment?
Explanation: The trickling filters are divided into conventional and high rate trickling filters.
The depth of the filter media of intermittent filter is
Explanation: The minimum depth of filter media of intermittent filter is 60cm. These filters give highly nitrified effluent.
Which of the following filter is used in anaerobic treatment of sewage?
Explanation: Biological filter is used in anaerobic treatment, whereas intermittent sand filter, trickling filter and contact filter are used in aerobic treatment of sewage.