| Groundwater is an important water resource in our country, the traditional groundwater in addition to iron and manganese removal process often appears the problem of excessive iron and manganese, and ultrafiltration technology has high retention efficiency, water quality and biological safety is guaranteed, and so on. The subject of the use of different process of iron and manganese removal and ultrafiltration technology combined to study the removal of iron and manganese and characteristics of membrane fouling. The effects of dosage of potassium permanganate and aeration intensity on the removal of iron and manganese and membrane fouling was carried out, the membrane cleaning and the best cleaning methods of different chemical cleaning methods were studied.Iron and manganese removal efficiency and membrane fouling characteristics were studied by using the method of direct ultrafiltration, aeration and ultrafiltration, and the removal of iron and manganese. The results show that the ultrafiltration membrane can effectively retain ferric iron, but the rejection of two valence manganese is not good; the combination process of aeration sand filtration and ultrafiltration can significantly improve the removal of iron and manganese removal efficiency and process stability, the ultrafiltration water iron and manganese content of 0.10mg/L and 0.02mg/L, meet the sanitary standard for drinking water(GB5749-2006). SEM EDS and XPS analysis indicated that the pretreatment process of cake layer morphology and transmembrane pressure difference has significant effect on, direct ultrafiltration process and aeration ultrafiltration process of filter cake layer is loose, dense filter cake layer formation of aeration- sand filtration ultrafiltration process are important factors causing it to run later transmembrane differential pressure fast growth rate; membrane on the surface of the cake layer is mainly composed of ferric iron particles is caused by membrane fouling and trans membrane pressure main component.The comparison of the effect of iron and manganese removal and the membrane fouling rate showed that the change of operating parameters had significant effect on the control of membrane fouling.The average content of total iron and total manganese in the ultrafiltration effluent was 0.25mg/L and 0.05mg/L in the best dosage of 15mg/L potassium permanganate in direct ultrafiltration process; The average content of total iron and total manganese in the ultrafiltration effluent was 0.21mg/L and 0.05mg/L in the best dosage of 3mg/L potassium permanganate in aeration and ultrafiltration process; With the increase of aeration rate, the removal efficiency of iron and manganese showed an increasing trend, TMP growth rate has been effectively controlled; When the amount of 1mg/L, the gas water ratio increased from 30:1 to 60:1, the TMP growth rate decreased by 82.22%.Differential pressure recovery results and surface morphology of membrane was compared with hydrochloric acid and sodium hypochlorite, sodium hypochlorite, sodium hypochlorite and ammonia and EDTA combination of three kinds of cleaning methods of membrane cleaning agent, the type and concentration of cleaning agent has significant effect of direct ultrafiltration, aeration and ultrafiltration and aeration sand filtration and ultrafiltration process of three kinds of ultrafiltration membrane cleaning; 100 mm HCl and sodium hypochlorite combination of aeration and sand filtration ultrafiltration process has the best cleaning effect,TMP recovery rate up to 96.30%,the membrane surface was smooth and the film hole is clearly visible;TMP recovery rate were 75.68%, 66.67% and 75% after cleaned by 5.5mM ammonia and sodium hypochlorite combination; 100 mM EDTA and sodium hypochlorite cleaning the way of direct ultrafiltration and aeration and ultrafiltration has better cleaning effect, TMP recovery rate were 96.30% and 98.43%, the membrane surface cake layer pollution has been removed, and the irreversible pollution has been restored. |
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