... pump-- provide the pressure to sand/carbon filter2. Sand filter-- get rid of turbidity, suspended matter, organic matter, colloid and so ... water pipes, drains and flushing water mains, as well as access to water, such as the composition of backwashing valve.1 ... water pipes, drains and flushing water mains, as well as access to water, such as the composition of backwashing valve. 1 ...