The role of biological processes in reducing both odor impact and pathogen content during mesophilic anaerobic digestion.
Mesophilic anaerobic digestion (MAD) produces renewable energy, but it also plays a role in reducing the impact of digestates, both by reducing odor and pathogen content. Ten full-scale biogas plants characterized by different plant designs (e.g. single digesters, parallel or serial digesters), plant powers (ranging from 180 to 999 kWe), hydraulic retention time (HRT) (ranging between 20 to 70 days) and feed mixes were monitored and odors and pathogens were observed in both ingestates and digestates. Results obtained indicated that MAD reduced odors (OU) from, on average, OUingestate=99,106±149,173 OU m(-2) h(-1) (n=15) to OU digestate=1106±771 OU m(-2) h(-1) (n=15). Pathogens were also reduced during MAD both because of ammonia production during the process and competition for substrate between pathogens and indigenous microflora, i.e. Enterobacteriaceae from 6.85∗10(3)±1.8∗10(1) to 1.82∗10(1)±3.82∗10(1); fecal Coliform from 1.82∗10(4)±9.09 to 2.45∗10(1)±3.8∗10(1); Escherichia coli from 8.72∗10(3)±2.4∗10(1) to 1.8∗10(1)±2.94∗10(1); Clostridium perfringens from 6.4∗10(4)±7.7 to 5.2∗10(3)±8.1 (all data are expressed as CFU g(-1) ww). Plants showed different abilities to reduce pathogen indicators, depending on the pH value and toxic ammonia content.
Università degli Studi di Milano, DISAA, Gruppo Ricicla, Lab. Agricoltura e Ambiente, Via Celoria 2, 20133 Milano, Italy.
Valentina
V
Orzi
Università degli Studi di Milano, DISAA, Gruppo Ricicla, Lab. Agricoltura e Ambiente, Via Celoria 2, 20133 Milano, Italy.
Barbara
B
Scaglia
Università degli Studi di Milano, DISAA, Gruppo Ricicla, Lab. Agricoltura e Ambiente, Via Celoria 2, 20133 Milano, Italy.
Samuele
S
Lonati
Università degli Studi di Milano, DISAA, Gruppo Ricicla, Lab. Agricoltura e Ambiente, Via Celoria 2, 20133 Milano, Italy.
Carlo
C
Riva
DG Agricoltura, Regione Lombardia, Piazza Lombardia, Milano, Italy.
Gabriele
G
Boccasile
Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via Bianchi 9, 25124 di Brescia, Italy.
Giovanni Loris
GL
Alborali
Università degli Studi di Milano, DISAA, Gruppo Ricicla, Lab. Agricoltura e Ambiente, Via Celoria 2, 20133 Milano, Italy; Università degli Studi di Milano, DISAA, Gruppo Ricicla - Lab. Biomasse e Agroenergia, c/o Parco Tecnologico Padano, Cascina Codazza, Via Einstein, 26900 Lodi, Italy. Electronic address: fabrizio.adani@unimi.it.
Fabrizio
F
Adani
D000397:Air Pollution / Q000032:analysis / Q000517:prevention & control*; D000693:Anaerobiosis; D056804:Biofuels; D001686:Biological Phenomena; D019149:Bioreactors; D009812:Odorants / Q000032:analysis*; D012722:Sewage / Q000382:microbiology*; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods*
D056804:Biofuels; D012722:Sewage
Anaerobic digestion; Odors; Organic wastes; Pathogens; Toxic ammonia