Manganese Ion Removal Effect In Water Purification Process And Study On Countermeasures Of Sludge Treatment

With the rapid development of society and economy,surface water manganese pollution phenomenon occurs frequently.This undoubtedly makes the treatment of drinking water more difficult that seriously threat to human use water for production and life.This paper mainly studies the current situation of manganese removal process in water purification plant.Based on the field investigation and detection,the parameters of the treatment plant,the dosing point of water treatment reagent and the situation of raw water quality are understood.The total manganese and dissolved manganese were determined by potassium periodate spectrophotometry,and the characteristics that migration and conversion and removal of raw water containing manganese in water purification process were studied.The batch testswere carried out to treat filter production wastewater,which was directly added to raw water based on different ratios.The suggestion on the treatment of the sludge in the water plant was put forward.The main research results include:（1）During the trial period,the water quality of the drinking water source of the water purification plant was good.The concentration of ammonia nitrogen,COD_Mn and nitrite in the raw water can meet the three criteria of China’s Evironmental Quality Standards For Surface Water,while the concentration of manganese is greater than 0.1mg/L,up to 0.30mg/L.Water plant apply potassium permanganate pre-oxidation + high-density sedimentation tank + sand filtration process,making concentration of manganese from the finished water is meet the China’s Drinking Water Health Standards（GB5749-2006）defined for manganese in drinking water of no more than0.1mg/L.（2）The total manganese and dissolved manganese in raw water and effluent of process unit were detected,the results show that total manganese,dissolved manganese and dissolved oxygen have little change in the depth of 4 meters,dissolved manganese accounts for about 50 of the total manganese,and when the water depth reaches 6 meters,the concentration of total manganese and dissolved manganese occurrence of surge,and increase with the increase of water depth,the highest reached 7.51mg/L,7.34mg/L.At the same time,the concentration of the dissolved oxygen in the bottom water is much lower than the surface layer and may form an anaerobic environment,which may lead to the surge of manganese in the bottom water.（3）In the treatment unit,the preoxidation of potassium permanganate can oxidize nearly60% of the soluble manganese in the raw water to the particles state,and improve the destabilization of the particulate manganese and the adsorption of minute quantities of dissolved manganese and removal rate of total manganese up to 85% or more.The removal of dissolvedmanganese by sand filtration process can be neglected.When the concentration of total manganese in raw water was 0.3mg/L,through potassium permanganate pre-oxidation + high-density sedimentation tank + sand filtration process makes the concentration of total manganese in finished water was only 0.01mg/L and the total removal rate was 90%.（4）The manganese elements in the wastewater are mainly in the form of dissolved.The coagulation and agitation test shows that the turbidity and the COD_Mn of the supernatant are higher than that of the coagulation agent,and the content of ammonia nitrogen and manganese remained basically unchanged.When the dosage of coagulant is 20mg/L,the turbidity and COD_Mn content are the lowest.The coagulation test showed that the ammonia nitrogen and manganese contents of the supernatant increased significantly with the increase of the reflux ratio of the wastewater.