Removal of ammonia nitrogen from surface water source
with the use of powdered zeolite

Summary

During flood periods increased concentrations of ammonia nitrogen in river water to 2–2.5 maximum permissible concentration are recorded at the Kirov water treatment plant. The assessment of possible use of powdered clinoptilolit containing zeolites in the existing water treatment process flow scheme to eliminate ammonium ions from natural water is given. The tests were carried out with the Viatka river water. After zeolite powder dosage of 0.1–1.3 mg/l addition into the water and 30 minutes mixing (200 rpm) slick was formed. During sedimentation a part of zeolite powder settled for 2–3 hours; however high turbidity remained for 24 hours. After adding 10 mg/l dosage of coagulant (aluminium sulfate) (as Al2O3) and Praestol 650TR flocculant complete precipitation of big flocks was achieved within 5–15 minutes. The ion-exchange capacity of powdered zeolite specimen – from 1.35 to 2.25 (as ammonia nitrogen) was determined. The highest ion-exchange capacity was recorded for Sokirnit natural zeolite (0.06–0.1 mm particle size). It was proved that ammonium ions exchange capacity depends on the concentration of clinoptilolit in the material (its concentration can change in the process of natural zeolite disintegrating and fractionating). The first pilot line of the plant with a capacity of 58 thousand m3 of water per day that provided for reducing ammonia nitrogen concentration to the level lower than MPC (2 mg/l) was assembled and tested at the Kirov water treatment plant.

Key words

flow chart , water treatment facilities , exchange capacity , clinoptilolit containing zeolite , ammonium ions

Enhancing the removal of hardness and iron ions from water

Summary

The numerical calculation of the problem of determining the concentration of components in the flowing water and in the stationary solid state – ionite granules, is presented. For three cations, namely Ca⁺², Mg⁺² and Fe⁺² subject to removal, the reduced concentrations in ionite and equilibrium concentrations in the treated water are calculated for each component. The calculations made show more than double increase of the surface coefficient of external mass transfer and of the volumetric coefficient of mass transport when the electric field intensity changes from 0 to 100 V/m. With that, the cycle operating time increases due to the increase of ionite exchange capacity use.

Key words

iron , water treatment , ion exchange , hardness ions , cathode , anode , ionite , exchange capacity , electric field , mass transfer