Study On Aluminum Salt Composite Flocculant Removing Humus Organic Matters In Groundwater

The raw water of the water supply plant derives the shallow groundwater of floodplain which is mainly supplied by river seepage.Meanwhile by the occasion of humus of floodplain area,CODMn of the raw water exceeds the standard of drinking water quality obviously.After raw water is treated by the water plant existing two stage filtering process,the finished water can not satisfy standards of drinking water(GB5749-2006).The subject aims at optimizing flocculating agent which is suitable for raw water quality characteristics,the pilot plant based on the optimizing flocculant simulating the water plant purification process utilizes enhanced micro-flocculation filtration process to strengthen the removal efficiency of natural organic matter,so that the finished water can satisfy the standards.By this way,the subject could provide theoretical and technical support for the water plant`s reconstruction.The analysis of raw water quality characteristics dedicates that the groundwater has the following characteristics: high iron,low manganese,high ammonia nitrogen,high organic matter,high turbidity,high color,low temperature,violent fluctuation of water quality,companying with characteristics of mixed contamination of groundwater and surface water.The organic matter in the water exist mainly in the form of humic acid and fulvic acid which have a large range of molecular weight and poor biodegradation.Under the pilot process,the removal efficiencies of CODMn of the four flocculants of PAC,PFC,FeCl3 and aluminum salt composite flocculant through the enhanced micro-flocculation filtration process were compared,And the suitable flocculant for the organic pollution characteristic of the water plant is the aluminum salt composite flocculant.The micro-flocculation reaction pH value of 6.85,6.6 5,6.35,6.15 under the conditions of the test results show that by reducing the micro-flocculation reaction pH can enhance removal effect of organic material by the performance of aluminum salt composite enhancing micro-flocculation filtrationBy the long-term stable operation at the the best suitable dosage of aluminum salt composite flocculant of 54.5mg/L,after micro-flocculation filtration process CODMn of the effluent water can sustain stably at the range of 2.8~2.9mg/L.The analysis of 3D-EEM and GPC indicate that after micro-flocculation filtration process the humic acid and fulvic acid in the effluent water decease obviously,meanwhile the molecular weight of organic matter deceases evidently.The pilot research indicates that the aluminum salt composite flocculant play a significant role in the removal of natural organic matter of humus class for the source of water which gets pollution characteristics of surface water and groundwater.