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[AGE28-P12] Biofiltration System Using Granulated Autoclaved Aerated Concrete (AAC) for Phosphorus Recovery from Municipal Wastewater in Vietnam
Keywords:Municipal wastewater, wastewater treatment, Autoclaved Aerated Concrete (AAC), phosphorus recovery
Municipal wastewater (MWW) is the main wastewater source that causes serious surface water pollution in Vietnam and approximately 80% of MWW discharges directly to the canals or inner rivers. MWW is characterized by high dissolved organic matter, ammonium, and phosphorus content. In the wastewater treatment plant, the organic matter is easily removed by biological treatment processes, but a high amount of chemicals are used for the removal of phosphorus (P), resulting in an increase in the operation cost for MWW treatment. Autoclaved Aerated Concrete (AAC) is one of the popular construction materials, it has a high porosity and large surface area, which can be expected as a low-cost suitable adsorbent from the viewpoints of microorganism inhabitants in the biofiltration system. Besides, AAC is rich in metal oxides/hydroxides that have a high affinity with phosphate (PO43-) in MWW. This study, therefore, investigated the P recovery (as well as the treatment of other organic pollutants) from MWW using a newly developed biofiltration system assembled with multiple bioreactors packed with granulated AAC. The results showed that the newly developed system well treated the organic pollutants in MWW and the treatment efficiencies became > 90% for COD, > 70% for total nitrogen, and > 90% for total P (meaning the high P recovery) and that the effluent after the treatment met well the national technical regulation on domestic wastewater discharge in Vietnam. The recovered P in the system (i.e., P-sorbed granulated AAC) would be expected to use as a recycled soil conditioner especially for improving agricultural soil health.