How to treat Underground water with Excessive iron and manganese

Trace amounts of iron and manganese are essential elements for the human body. But when there is excessive amount of iron and manganese in water, the color and odor of the water will deteriorate, and manganese oxidants are easy to deposit on the inner wall of the pipe and cause the phenomenon of "black water". GB5749 stipulates, that iron should not exceed 0.3mg/L and manganese should not exceed 0.1mg/L in drinking water.

Iron and manganese removal generally have 2 methods, the removal of iron generally uses aeration oxidation while the removal of manganese generally uses contact oxidation:

Aeration oxidation refers to raw water after aeration fully dissolve oxygen and disperse CO2, increase the pH value, all or most of the Fe2+ in the water is oxidized to Fe3+, and then enters the filter for filtration.

Contact oxidation refers to the raw water after aeration with dissolved oxygen enters the filter quickly without complete oxidation. After a certain period, the filter material forms an active filter membrane on its surface and catalytic action of it is used for iron and manganese removal.

1. Water drop aeration, suitable for projects with low iron and manganese in water and low requirements for aeration. Note that if the drop water level or drop height is selected to be a smaller value, the single-width flow rate should also be smaller.

2. Water spraying aeration. There are two types of water spraying devices: perforated pipe and lotus head, but the holes are easy to be blocked, so suitable for iron removal in small gravity filters with iron less than 10mg/L in water. Perforated pipes can also be installed in the aerator on the air tower or on the water drop aeration tank, to combine with other aeration devices

3. Jet aeration, suitable for small projects with low iron and manganese in water and low requirements for CO2 removal.

4. Compressed air aeration is generally supplied by an air compressor and mixed by an air-water mixer, suitable for large-scale projects with high iron and manganese in water.

5. Contact aeration tower, suitable for large-scale projects with iron of less than 10mg/L in water, so as to prevent iron deposits from quickly clogging the packing. Generally, the packing layer should be cleaned every 1~2a, and to facilitate the cleaning, the layer distance should not be less than 600mm.

6. Impeller type surface aeration, high dissolved oxygen efficiency, can fully dissipate CO2 and greatly increase the pH value, and have strong adaptability.

When iron and manganese coexist, the iron less than 2.0～5.0mg/L and the manganese less than 1.5mg/L, single-stage filtration can generally remove iron and manganese at the same time. When the iron and manganese in water exceeds the above value, iron will significantly interfere with manganese removal, the process of removing iron first and then removing manganese should be adopted, and the first-level iron removal effect should be strictly controlled.

The quality of groundwater with excessive iron and manganese is very different. Therefore, in the selection of iron and manganese removal process, more detailed raw water quality data should be mastered. If possible, the iron and manganese removal test should be carried out.

More inquiries related to Iron and manganese removal please contact:

Mob& Wechat& WhatsApp: (+86)13544774483

Email: sales010@water-sy.com

We will provide high-quality, all-round comprehensive professional services for project consulting, system design, manufacturing, installation and commissioning, personnel training, etc.