What Are The Common Malfunctions Of Manganese Sand Filter Aeration Systems? - News

Common malfunctions of manganese sand filter aeration systems can be categorized into three types: substandard treatment effect, abnormal operating parameters, and damaged equipment components. Considering the characteristics of high-temperature, high-hardness water in the Dazu area of Chongqing, the specific breakdown is as follows:

1. The treatment effect is not up to standard (directly affecting the quality of the effluent).

Excessive iron and manganese in effluent
Symptoms : Yellowish effluent (excessive iron, Fe > 0.3 mg/L) or blackish effluent (excessive manganese, Mn > 0.1 mg/L).

reason :

Insufficient aeration (DO < 5 mg/L) leads to incomplete oxidation of iron and manganese (e.g., clogged aeration heads, reduced blower airflow).

If the filter media is ineffective (MnO₂ content < 30%) or the filter media layer thickness is insufficient (< 1.2m), it will be unable to retain oxidation products;

In water with high hardness, calcium and magnesium scale can clog aeration heads, reducing aeration efficiency by more than 40%.

Turbidity increased
Symptoms : Effluent turbidity >5 NTU (normal <1 NTU), accompanied by increased suspended solids.

Causes : Incomplete backwashing (time < 10 minutes or intensity < 12 L/(m²・s)) leads to the accumulation of iron and manganese oxides, or the water flow is short-circuited after the filter media clumps together.

II. Abnormal operating parameters (indicating potential malfunction)

Excessive pressure difference
Indication : Inlet and outlet pressure difference > 0.15 MPa (normal 0.04-0.05 MPa).

reason :
Influent suspended solids >10mg/L without pretreatment led to filter bed clogging;

Insufficient backwashing intensity (<10L/(m²・s)) leads to the accumulation of iron and manganese oxides in the gaps between the filter media.

In water with high hardness, calcium and magnesium deposits clog the pores of filter media.

Dissolved oxygen abnormality
Symptoms : Influent DO < 5 mg/L or localized hypoxia.

reason :
Aerator blockage (covered by iron and manganese oxides or biofilm) or pipeline leakage;

A fan malfunction (loose belt, worn impeller) leads to a decrease in air supply.

Poor backwashing effect

Symptoms : Turbid backwash drainage and loose filter media.

reason :
Inappropriate air-water combined backwashing parameters (air wash time < 3 minutes, water flushing intensity < 12 L/(m²・s));
Water distributor/air distributor clogged (blocked by iron sludge, filter media fragments).

III. Damaged equipment components (hardware malfunctions require immediate attention)

Aeration device failure

Characteristics : Few bubbles or no bubbles in some areas.

reason :

Aeration heads/aeration pipes are clogged by iron and manganese oxides and calcium and magnesium scale (especially serious in high hardness water).

Aeration membrane aging and cracking (high temperature water quality accelerates aging);

Insufficient air pressure in the fan (blade wear, air intake filter blockage).

Valve leakage or jamming
Symptoms : Valves are leaking water or air, or cannot be opened or closed normally.

reason :

Aging of seals (O-rings, gaskets) (high humidity environment accelerates aging);

The valve core is stuck by iron sludge and filter media fragments (incomplete backwashing allows contaminants to enter the valve).

Filter media loss or damage

Characteristics : The backwash drainage contains a large amount of manganese sand, and the filter media layer height is <1.2m.

reason :
The backwashing intensity is too high (>25L/(m²・s)) or the filter media gradation is unreasonable (the proportion of fine material is too high);

The water distributor's filter screen is damaged, and the filter media is leaking out of the drain.

Instrument display abnormal

Symptoms : Pressure gauge or flow meter malfunction, or DO meter deviation > ±5%.

Causes : The instrument is contaminated with iron and manganese oxides (due to lack of regular cleaning), or the sensor is faulty or improperly installed.