Study On Enhanced Removal Of Natural Organic Matter From Surface Water By Circulating Granulation Fluidized Bed

Ensuring the safety of drinking water is very important for maintaining people’s health.Therefore,how to improve the quality of water has become the focus of today’s academic circle.By combining the circulating granulation fluidized bed with pre-adsorption/pre-oxidation,the removal effect of turbidity and organic matter in micro-polluted reservoir was explored,and the removal mechanism of organic matter was also explored.In a circulating granulation fluidized bed,the treatment effect of organic matter is mainly affected by the dosage of PACl and the reaction time after the dosage of PACl.The dosage of PAM and the stirring speed mainly affect the operation of the fluidized bed system.In this experiment,the optimal operating conditions were PACl dosage 24mg/L,PAM dosage 0.9mg/L,stirring speed 7r/min,reaction time 65s.Compared with ordinary coagulation,the removal rate of UV₂₅₄,COD_Mn and DOC can be increased by up to 13%,18%and 25%respectively.Compared with the traditional coagulation and precipitation process,the circulating granulation fluidized bed has improved the treatment capacity of organic matter,and can be used as a technology to treat high-load organic matter,reducing the treatment pressure for the subsequent treatment process.When powdered activated carbon（PAC）was added for pre-adsorption,the strengthening effect of PAC was gradually increased with the increase of fulvic acid content in raw water.The removal rates of COD_Mn,UV₂₅₄ and DOC increased by 16.89%,6.73%and 10.88%,respectively,when raw water only contained fulvic acid.The particle density of the junction group decreased with the increase of PAC dosage.The strengthening effect of pre-oxidation is better than that of pre-adsorption when the concentration of humic acid in raw water is large.Among them,the pre-oxidation effect of Na Cl O is the best,and the removal rates of COD_Mn,UV₂₅₄ and DOC are 78.70%,63.35%and 63.85%when humic acid is only added into raw water.Both kinds of pre-oxidants can increase the density of the agglomeration,increase the settlement performance of the agglomeration,and reduce the sand loss during continuous operation of the circulating agglomeration pelletizing fluidized bed.