Chemical Preoxidation Coupled With Bio-manganese Oxidation Enhanced Water Purification Efficiency

Excess nutrient matters in water,such as nitrogen and phosphorus,may lead to the algae blooms,which deteriorate drinking water quality.To eliminate the threatens of these matters on drinking water,optimizing the treatment process of drinking water is significant.Various efforts have been paid to process optimization of drinking water plant,But most of them focused on improving only one step of the whole processing,such as the chemical pre-oxidation and sand filter reformation often adopts a single-stepoptimizationandupgrading,ignoringthepossible superposition of the two process combinations.Here,chemical pre-oxidation coupled biomanganese oxidation process was designed,and its efficiency of water purification was evaluated.The chemical pre-oxidation experiments carried out in micro-polluted water,demonstrating that natural organic matter Tyr was effectively removed by potassium permanganate and iron manganese oxide but BP-4 was not.Unfortunately,Mn²⁺was released during these pre-oxidation process,resulting the secondary pollution of water.Tyr was effectively removed by serving as the nutrient source of the manganese oxidizing bacteria Pseudomonas sp.QJX-1,and the Mn²⁺generated during this process would be utilized by Pseudomonas sp.QJX-1 to form BMO,which realized the removal of BP-4.The performance of chemical pre-oxidation coupled bio-manganese oxidation process was further assessed in algal bloom water.The results showed that potassium permanganate pre-oxidation efficiently inactivated Microcystis aeruginosa,but caused second pollution due to the leakage of intracellular organic matter and residual Mn²⁺.The residual Tyr and Mn²⁺were effectively removed by Pseudomonas sp.QJX-1,but BMO formed by bio-manganese oxidation can not remove MC-LR.To verify the feasibility of chemical oxidation coupled with bio-manganese oxidation process,the water from Chaohu Lake during algal bloom event was obtained and used as the influent.The results showed that the chemical pre-oxidation coupled bio-manganese oxidation not only effectively removed the pre-oxidation residual Mn²⁺,but also significantly reduced the organics.What's more,it confirmed the existence of bio-manganese oxidation in actual water plant sand filter.Therefore,combining biogenic-manganese oxidation technology with chemical oxidation would be an efficient method to deeply purify drinking water.