title: Monitoring the aeration efficiency and carbon footprint of a medium-sized WWTP: experimental results on oxidation tank and aerobic digester.
abstract: The efficiency of aeration systems should be monitored to guarantee suitable biological processes. Among the available tools for evaluating the aeration efficiency, the off-gas method is one of the most useful. Increasing interest towards reducing greenhouse gas (GHG) emissions from biological processes has resulted in researchers using this method to quantify N2O and CO2concentrations in the off-gas. Experimental measurements of direct GHG emissions from aerobic digesters (AeDs) are not available in literature yet. In this study, the floating hood technique was used for the first time to monitor AeDs. The floating hood technique was used to evaluate oxygen transfer rates in an activated sludge (AS) tank of a medium-sized municipal wastewater treatment plant located in Italy. Very low values of oxygen transfer efficiency were found, confirming that small-to-medium-sized plants are often scarcely monitored and wrongly managed. Average CO2and N2O emissions from the AS tank were 0.14 kgCO2/kgbCODand 0.007 kgCO2,eq/kgbCOD, respectively. For an AeD, 3 × 10-10kgCO2/kgbCODdirect CO2emissions were measured, while CO2,eqemissions from N2O were 4 × 10-9kgCO2,eq/kgbCOD. The results for the AS tank and the AeD were used to estimate the net carbon and energy footprint of the entire plant.
authors.affiliation: a School of Engineering , University of Basilicata , Potenza , Italy.
authors.forename: Marianna
authors.initials: M
authors.lastname: Caivano
authors.affiliation: b Department of Civil and Environmental Engineering - DICEA , University of Florence , Florence , Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Bellandi
authors.affiliation: a School of Engineering , University of Basilicata , Potenza , Italy.
authors.forename: Ignazio M
authors.initials: IM
authors.lastname: Mancini
authors.affiliation: a School of Engineering , University of Basilicata , Potenza , Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Masi
authors.affiliation: c Acquedotto Lucano s.p.a. , Potenza , Italy.
authors.forename: Rosanna
authors.initials: R
authors.lastname: Brienza
authors.affiliation: c Acquedotto Lucano s.p.a. , Potenza , Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Panariello
authors.affiliation: b Department of Civil and Environmental Engineering - DICEA , University of Florence , Florence , Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Gori
authors.affiliation: a School of Engineering , University of Basilicata , Potenza , Italy.
authors.forename: Donatella
authors.initials: D
authors.lastname: Caniani
mesh_terms: D000393:Air Pollutants / Q000032:analysis; D064751:Ammonium Compounds / Q000032:analysis; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D002245:Carbon Dioxide / Q000032:analysis; D058572:Carbon Footprint; D004784:Environmental Monitoring; D007558:Italy; D009566:Nitrates / Q000032:analysis; D009573:Nitrites / Q000032:analysis; D009609:Nitrous Oxide / Q000032:analysis; D010084:Oxidation-Reduction; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D000393:Air Pollutants; D064751:Ammonium Compounds; D009566:Nitrates; D009573:Nitrites; D014874:Water Pollutants, Chemical; D002245:Carbon Dioxide; D009609:Nitrous Oxide
keywords: Aeration efficiency; aerobic digestion; carbon and energy footprint; greenhouse gases; off-gas method