Physical Properties

Operating Condition

• Backwash: Sufficient rate using treated water to produce approximately 30% bed
  expansion.
• Rinse: At normal service flow rate for 5 minutes or until the effluent is acceptable.
• Capacity: 350 ~ 500 g/m2 of bed area based on potassium permanganate demand.
  In addition to the required continuous regeneration a 70 cm minimum bed of specially sized. It is also required in any case the pressure drop should not exceed 0.70 ~ 0.85
  Kg/cm2.

General Notes

Raw water having a pH of 6.2 or higher can be passed through Zeomangan without pH correction; water having a pH lower than 6.2 should be pH corrected to 6.2 – 6.5 before passing through the Zeomangan. If a pH higher than 6.5 is desired in the water system, the additional alkali should be added after the filters due to the adverse reaction (formation of a colloid) that sometimes occurs with the iron and alkali with pH over 6.5. KMnO4 solution Strength – with continuous regeneration operation the KMnO4 can be any concentration up to 30 g/L.

Flow Rate:

Normal flow rates with continuous regeneration operation are 5~12 m/hr. Higher concentration of iron and manganese usually require lower flow rates for equivalent run lengths. Rates in excess of 12 m/hr can usually be tolerated but a pilot unit should be operated to determine the effluent quality and run length.

The run length between backwashes can be estimated as follows:

Example : What is run length on a water containing 1.7mg/L iron and 0.3 mg/L manganese at 10m/hr operating rate?

At 500 g/m2 loading ÷ 2.3 mg/L = 217 m

At 10 m/hr service rate, 217/10 = 21.7 hr

Therefore the backwash frequency is approximately every 20-24 hours of operation.