Microwave, ultrasonic and chemo-mechanical pretreatments for enhancing methane potential of pulp mill wastewater treatment sludge

Wastewater Treatment and Reclamation: A Review of Pulp and Paper Industry Practices and Opportunities

“…In fact, some of the generated effluents already have a relatively high temperature, so they can already be handled in the thermophilic range without further chilling the effluent. Anaerobic wastewater treatment operations are often regarded favorably by environmental advocates because they actively generate methane that can be retrieved and used in place of other combustible fuels (Maat and Habets 1987;Tabatabaei et al 2010;Saha et al 2011;Meyer and Edwards 2014;Sanusi and Menzes 2014). GHG emissions by on-site and off-site processes in a typical industrial wastewater treatment plant that used aerobic, anaerobic, and hybrid anaerobic/aerobic treatment processes were studied by Bani Shahabadi et al (2009Shahabadi et al ( , 2010 and Yerushalmi et al (2011).…”

“…Moreover, reactors working in the thermophilic range managed to work at higher volumetric loading rates than AnMBRs operating within the mesophilic range. Saha et al (2011) found that when thermophilic conditions were employed during anaerobic treatment, there was little benefit of pretreating the sludge by any of the methods that they considered. …”

“…The rupturing of P&P secondary sludge by a rapid release in pressure was found to be an effective method to render the sludge more amendable for subsequent anaerobic treatment (Stephenson et al 2007). A drawback of many of these systems is the energy costs of operation.Ultrasonic treatment of secondary sludge was considered by Saha et al (2011) and Bayr et al (2013). Saha et al (2011) found ultrasonication to be effective for dispersing the sludge and breaking down the solids.…”

“…Enzymatic treatment with a cellulose-decomposing cocktail was found to be effective, especially in combination with the hydrothermal treatment (Bayr et al 2013). Saha et al (2011) found microwave pretreatment to be effective for secondary sludge from a pulp mill, enabling more effective action of an anaerobic treatment stage. Specific methane yields were increased by 90% compared to controls.…”

Optimization of H2O2 dosage in microwave-H2O2 process for sludge pretreatment with uniform design method

“…Therefore, recently many researchers have focused on sludge pretreatment technologies mainly based on physical, chemical, and biological methods and their combinations for minimization of sludge production, improvement of sludge dewaterability and enhancement of sludge anaerobic digestion (Neyens and Baeyens, 2003;Odegaard, 2004;Bordeleau and Droste, 2011;Chi et al, 2011;Coelho et al, 2011;Tyagi and Lo, 2011), and notably the hybrid sludge pretreatment technologies endow with promising outcomes through neutralizing the associated drawbacks with individual pretreatment techniques. As one of the most promising technologies, e.g., microwave pretreatment was proved to be the most effective for enhancing methane potential of pulp mill waste sludge, compared with ultrasonic and chemo-mechanical methods (Saha et al, 2011), studies of microwave technology and its combined processes for sludge pretreatment have received increasing attention in recent years. Microwave with pressure seal (Liao et al, 2005a), microwave under ambient pressure conditions (Cheng, 2008;Cheng et al, 2010;Yan et al, 2009), microwave-acid, microwave-alkali (Cheng, 2008;Cheng et al, 2009;Doǧan and Sanin, 2009;Yan, 2010;Chi et al, 2011;Chang et al, 2012;Erden, 2012), microwave-H 2 O 2 process (Eskicioglu et al, 2006(Eskicioglu et al, , 2007(Eskicioglu et al, , 2009Liao et al, 2005a;2005b;Lo et al, 2008;Wang, 2009;Wang et al, 2009aWang et al, , 2009bWong et al, 2006aWong et al, , 2006bYu et al, 2010aYu et al, , 2010b have been used to improve sludge disintegration and sludge disinfection, among which the microwave-H 2 O 2 (MW-H 2 O 2 ) process has been shown to be the most effective.…”