What Are The Impacts Of Common Malfunctions in The Manganese Sand Filter Aeration System On Water Quality?

Common faults of the manganese sand filter aeration system have an impact on water quality mainly in the following aspects: 1. The iron and manganese content in the effluent exceeds the standard (core impact) Insufficient aeration leads to incomplete oxidation If the aeration device is blocked, the air volume is insufficient, or the organic matter content of the raw water is high, the dissolved oxygen (DO) in the water is <5mg/L, and ferrous iron (Fe²⁺) and manganese (Mn²⁺) cannot be fully oxidized into Fe³⁺ and MnO₂ causes iron in the effluent to exceed 0.3mg/L and manganese to exceed 0.1mg/L, making the water yellow and accompanied by a rusty smell. Actual manifestations: water turns yellow after standing and stains appliances (such as washing machines and water heaters). Long-term drinking may cause gastrointestinal discomfort or the risk of excessive heavy metals. The filter material fails or is contaminated. The manganese sand has been used for more than 3-5 years or is covered with oil and algae, and its catalytic oxidation ability is reduced. The filter material layer is hardened or disordered (the backwash intensity is too strong), causing the iron and manganese oxides to be unable to be retained and directly penetrate the filter layer. Actual manifestations: The effluent turbidity increases (>3NTU), and iron and manganese precipitates block subsequent pipelines or equipment (such as water purifiers and boilers). 2. Sensory deterioration of water quality, increased turbidity, blockage of the filter layer (inlet water turbidity >10 NTU) or incomplete backwashing, resulting in outlet water turbidity >3 NTU and turbid water quality, affecting drinking and production water (such as washing, printing and dyeing). Increased odor. Insufficient oxidation of iron and manganese or contamination of the filter material may breed bacteria, producing a rancid or metallic smell, reducing the water experience. 3. Abnormal chemical indicators and pH fluctuations. Insufficient aeration or strong acidity of the raw water (pH<6.5) inhibits iron and manganese oxidation. If excessive chemicals are added to adjust the pH, the pH of the effluent may be >9.0, causing calcium carbonate to precipitate and block the filter material. Accumulation of interfering ions. The incoming water contains excessive sulfide, nitrite and other reducing substances, which preferentially consume dissolved oxygen, causing manganese to be unable to be oxidized. Too high iron content (>10 mg/L) will dominate the oxidation and inhibit the removal of manganese. 4. Chain reaction of equipment failure: Excessive pressure difference leads to "penetration" filter layer blockage (pressure difference >0.15MPa), which will destroy the filter material structure, iron and manganese oxides will be discharged directly with the water flow, and the water quality will deteriorate instantly. Backwash failure aggravates pollution. Backwash intensity is insufficient (<15L/(m²·s)) or water distribution is uneven. Iron mud on the surface of the filter material cannot be peeled off. The filtration cycle is shortened to less than 50% of the design value, and water quality fluctuates frequently. Special reminder for the Dazu area in Chongqing: If the iron and manganese content in local groundwater is high (such as >5mg/L), the water quality problems caused by aeration failure will be more significant: High-concentration iron-manganese water: When aeration is insufficient, iron-manganese oxides are easy to deposit on the inner walls of the pipes, forming "red rust" and clogging the pipe network; High temperatures in summer: Algae reproduce quickly and the risk of filter material contamination is high. Pre-oxidation (such as adding sodium hypochlorite) needs to be strengthened or the backwash cycle should be shortened to 5-7 days/time. By regularly monitoring dissolved oxygen (≥5mg/L), pH (7.5-8.5) and turbidity (≤3NTU), the impact of aeration system failures on water quality can be discovered in time and measures can be taken.