Chemically coupled microwave and ultrasonic pre-hydrolysis of pulp and paper mill waste-activated sludge: Effect on sludge solubilisation and anaerobic digestion
Journal
Environmental Science and Pollution Research
Journal Volume
21
Journal Issue
9
Pages
6205-6217
Date Issued
2014
Author(s)
Abstract
The effects of alkali-enhanced microwave (MW; 50-175 °C) and ultrasonic (US) (0.75 W/mL, 15-60 min) pretreatments, on solubilisation and subsequent anaerobic digestion efficiency of pulp and paper mill waste-activated sludge, were investigated. Improvements in total chemical oxygen demand and volatile suspended solids (VSS) solubilisation were limited to 33 and 39 % in MW pretreatment only (175 °C). It reached 78 and 66 % in combined MW-alkali pretreatment (pH 12 + 175 °C), respectively. Similarly, chemical oxygen demand and VSS solubilisation were 58 and 37 % in US pretreatment alone (60 min) and it improved by 66 and 49 % after US-alkali pretreatment (pH 12 + 60 min), respectively. The biogas yield for US 60 min-alkali (pH 12)-pretreated sludge was significantly improved by 47 and 20 % over the control and US 60 reactors, respectively. The biogas generation for MW (150 °C)-alkali (pH 12)-pretreated sludge was only 6.3 % higher than control; however, it was 8.3 % lower than the MW (150 °C) reactor, which was due to the inhibition of anaerobic activity under harsh thermal-alkali treatment condition. © 2014 Springer-Verlag Berlin Heidelberg.
Subjects
Alkali pretreatment; Anaerobic digestion; Biogas potential; Microwave; Pulp and paper mill waste-activated sludge; Ultrasonication
SDGs
Other Subjects
activated sludge; anoxic conditions; biogas; chemical oxygen demand; hydrolysis; pH; pulp and paper industry; solubilization; volatile substance; United States; anaerobic growth; article; biochemical oxygen demand; bioremediation; chemistry; hydrolysis; industrial waste; methodology; microwave radiation; paper; sewage; ultrasound; waste water; water pollutant; Anaerobiosis; Biodegradation, Environmental; Biological Oxygen Demand Analysis; Hydrolysis; Industrial Waste; Microwaves; Paper; Sonication; Ultrasonics; Waste Disposal, Fluid; Waste Water; Water Pollutants
Type
journal article