Manganese Removal Drinking Water Treatment

Pollution characteristics and risk control

Divalent manganese (Mn²⁺) is commonly found in groundwater (concentrations often reach 0.1-2.0 mg/L)

Exceeding 0.1 mg/L will cause black water in pipes (national standard limit 0.1 mg/L)

Long-term exposure may cause damage to the nervous system (WHO recommended limit 0.08 mg/L)

Differentiation of manganese forms treatment process

1. Catalytic oxidation filtration system

Modified manganese sand filter (manganese dioxide coating thickness ≥ 80 μm)

Contact time ≥ 12 minutes (pH control range 6.2-8.5)

Simultaneous removal of iron/manganese (Fe²⁺＜0.3 mg/L, Mn²⁺＜0.05 mg/L)

2. Ion exchange process

Sodium type strong acid cationic resin (exchange capacity ≥ 2.0 eq/L)

Manganese ion replacement rate ＞95% (regeneration cycle 300-500 bed volumes)

Applicable to low concentration manganese pollution (＜0.5 mg/L)

3. Deep oxidation technology

Ozone catalytic oxidation (O₃ addition 1.5-3.0mg/L, CT value ≥2.0)

Potassium permanganate enhanced oxidation (KMnO₄/Mn²⁺ molar ratio 1.8:1)

Hydroxy radical assistance (UV/H₂O₂ system 185nm ultraviolet lamp)

Key engineering control nodes

Redox potential (ORP) control:

Primary oxidation>650mV

Secondary filtration<200mV

Anti-manganese leakage protection:

Online monitoring of residual manganese in filtered water (<0.02mg/L)

Automatic backwash trigger (head loss> 0.05MPa)

Operation and maintenance technical points

Regeneration of manganese sand filter media:

KMnO₄ solution immersion (concentration 1.5%, duration 6h)

Regeneration efficiency > 90%

Ion exchange resin anti-poisoning:

Influent COD limit < 3mg/L

Regular resuscitation treatment (10%NaCl+1%NaOH)

Water quality verification indicators

Atomic absorption spectrometry detection limit ≤ 0.001mg/L

Filtered water turbidity < 0.3NTU (inhibits manganese re-precipitation)

Manganese content in water at the end of the network < 0.05mg/L (72h stability test)

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