title: Comparative study of low-energy ultrasonic and alkaline treatment on biosludge from secondary industrial wastewater treatment.
abstract: In this study, low-energy ultrasonic (3 and 6 kJ/g volatile solids of feed biomass (FB) which was lower than the heat value of the FB), alkaline, and ultrasonic-alkaline pretreatments were applied on FB, a biosludge from secondary industrial wastewater treatment. Biochemical methane potential (BMP), particle size distribution, Biomass Stress Index (BSI™), soluble chemical oxygen demand (SCOD), protein, carbohydrate, and size-exclusion chromatography (SEC) fingerprints were used to comparatively study the mechanisms of these pretreatment methods. The results indicated that low-energy ultrasonication and alkali exhibited significantly different impacts on the FB. After ultrasonication with energy input of 6 kJ/g-VS, the average particle size of FB was reduced from 102.6 to 19.4 µm. However, ultrasonication had no obvious effect on microbial cells rupture, solubilization of protein and carbohydrate, and SEC fingerprint. Consequently, low-energy ultrasonication could not enhance methane generation. However, after alkaline pretreatment with dosage of 0.3 g-NaOH/g-VS, SCOD, soluble protein, and soluble carbohydrate concentration of FB increased from 0.66, 0.00, 0.07 to 2.83, 0.83, 0.47 g/L, respectively. At the same time, BSI™ increased from 5.3% to 96.8%, and the SEC fingerprint changed significantly. Consequently, the methane generation in the BMP test increased from 68.9 to 135.0 mL. Ultrasonic-alkaline pretreatment was similar to alkaline pretreatment in terms of methane generation. Based on this study, alkaline pretreatment is recommended over both low-energy ultrasonic and low-energy ultrasonic-alkaline pretreatment to enhance the biodegradability of FB.
authors: a School of Civil and Environmental Engineering , Nanyang Technological University , Singapore , Singapore.
authors: Dongzhe
authors: D
authors: Li
authors: Youming
authors: Y
authors: Tan
authors: Yan
authors: Y
authors: Zhou
authors: Santosh
authors: S
authors: Pathak
authors: Antonius Yudi
authors: AY
authors: Sendjaja
authors: Maszenan
authors: M
authors: Abdul Majid
authors: Prannoy
authors: P
authors: Chowdhury
authors: Wun Jern
authors: WJ
authors: Ng
mesh_terms: D000468:Alkalies / Q000737:chemistry*; D000693:Anaerobiosis; D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D002241:Carbohydrates / Q000032:analysis; D002850:Chromatography, Gel; D008697:Methane / Q000032:analysis; D010316:Particle Size; D011506:Proteins / Q000032:analysis; D012722:Sewage / Q000032:analysis* / Q000382:microbiology*; D014465:Ultrasonics / Q000379:methods*; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods
chemical_list: D000468:Alkalies; D002241:Carbohydrates; D011506:Proteins; D012722:Sewage; D008697:Methane
keywords: Biomass Stress Index; extracellular polymeric substances; methane generation; particle size; size-exclusion chromatography fingerprint