The percentage of COD removal was calculated with the following formula:was composed of diluted semi-skimmed milk or whole milk, supplemented with nutrients and alkalinity. The reactors were seeded with approximately 4 L of flocculent sludge adapted to dairy wastewater from an industrial wastewater treatment plant. The inoculation sludge had a SMA (specific methanogenic activity) of 7.1 mL CH4/g VSS/day measured with sodium acetate at (35 ± 1) °C. Throughout the entire experiment, effluent from the reactors was collected in 24 h composite samples. All physical-chemical determinations were made according to Standard Methods [48]. The produced biogas was measured by wet gas meters (Schlumberger). Methane content in biogas was monitored using a Shimadzu GC – 9a gas chromatograph equipped with a Supelco Molecular Sieve 5 A column and a Thermal Conductivity Detector (T = 100 °C). Injection temperature was 45 °C and Helium was used as carrier gas (P = 4.4 kg/cm2). Volatile fatty acids determination was carried out in a Chrompack CP 9001 gas chromatograph equipped with a Chrompack CP – sil5 – CB column and a Flame Ionization Detector (T = 300 °C). The injection temperature was 270 °C and Helium was used as carrier gas with a volumetric flow of 8 mL/min. Biomass samples for FISH (Fluorescence In Situ Hybridization) analyses were collected immediately before each applied shock, at the end of the shock period, and 20 days after the end of the shock. After collection, biomass samples were immediately frozen at −20 °C. For (FISH) experiments, samples were allowed to reach room temperature and were vortexed for 5 min to disrupt granules and other aggregates, and subsequently fixed with formaldehyde (4% v/v). Fixed samples were washed
The percentage of COD removal was calculated with the following formula:was composed of diluted semi-skimmed milk or whole milk, supplemented with nutrients and alkalinity. The reactors were seeded with approximately 4 L of flocculent sludge adapted to dairy wastewater from an industrial wastewater treatment plant. The inoculation sludge had a SMA (specific methanogenic activity) of 7.1 mL CH4/g VSS/day measured with sodium acetate at (35 ± 1) °C. Throughout the entire experiment, effluent from the reactors was collected in 24 h composite samples. All physical-chemical determinations were made according to Standard Methods [48]. The produced biogas was measured by wet gas meters (Schlumberger). Methane content in biogas was monitored using a Shimadzu GC – 9a gas chromatograph equipped with a Supelco Molecular Sieve 5 A column and a Thermal Conductivity Detector (T = 100 °C). Injection temperature was 45 °C and Helium was used as carrier gas (P = 4.4 kg/cm2). Volatile fatty acids determination was carried out in a Chrompack CP 9001 gas chromatograph equipped with a Chrompack CP – sil5 – CB column and a Flame Ionization Detector (T = 300 °C). The injection temperature was 270 °C and Helium was used as carrier gas with a volumetric flow of 8 mL/min. Biomass samples for FISH (Fluorescence In Situ Hybridization) analyses were collected immediately before each applied shock, at the end of the shock period, and 20 days after the end of the shock. After collection, biomass samples were immediately frozen at −20 °C. For (FISH) experiments, samples were allowed to reach room temperature and were vortexed for 5 min to disrupt granules and other aggregates, and subsequently fixed with formaldehyde (4% v/v). Fixed samples were washed
การแปล กรุณารอสักครู่..