Effects of Sludge Concentration and Disintegration/Solubilization Pretreatment Methods on Increasing Anaerobic Biodegradation Efficiency and Biogas Production

Abstract

It is urgent to determine suitable municipal sludge treatment solutions to simultaneously minimize the environmental negative impacts and achieve sustainable energy benefits. In this study, different sludge pretreatment techniques were applied and investigated to enhance the sludge solubility and, subsequently, facilitate the anaerobic biodegradation performance of the mixed sludge under different sludge concentrations and pretreatment techniques. The sludge characteristics before and after pretreatment and batch experiments of anaerobic digestion of sludge samples under different conditions were analyzed and discussed. The results showed that the mechanical pretreatment method, alone and in combination with low-temperature heat treatment, significantly improved the sludge solubility, with the highest solubility at 39.23%. The maximum biomethane yield achieved was 0.43 m3/kg after 10 d of anaerobic digestion of a 3% sludge sample subjected to mechanical and thermal pretreatment prior to anaerobic biodegradation. In comparison, it took more than 28 d to achieve the same biomethane production with the unpretreated sludge sample. Mechanical pretreatment and subsequent heat treatment showed a high ability to dissolve sludge and, subsequently, accelerate anaerobic digestion, thereby providing promising prospects for increasing the treatment capacity of existing and new sludge treatment plants.

Sludge Thermal Hydrolysis for Mitigating Oxidative Stress of Polystyrene Nanoplastics in Anaerobic Digestion: Significance of the Solids Content

“…The cumulative methane yields for controls (Control-4%TS, Control-8%TS, and Control-12%TS) were 208.31 ± 1, 193.92 ± 2.3, and 157.81 ± 2 mL CH 4 /g COD (Figure ). Thus, with an increasing solids content, methane yields decreased ( p -value = 0.006), which could be related to increased sludge viscosity and mass transfer limitation at a higher solids content . The THP at 160 °C increased methane yield (Table S3) for the sample with 12% TS (THP-12%TS), indicating that the THP at a higher solids content could alleviate such a mass transfer limitation by disintegrating sludge flocks and thereby increasing the methane yield up to 62% compared to the corresponding control (Control-12%TS) (Figure S1).…”

“…Thus, with an increasing solids content, methane yields decreased (p-value = 0.006), which could be related to increased sludge viscosity and mass transfer limitation at a higher solids content. 22 The THP at 160 °C increased methane yield (Table S3) for the sample with 12% TS (THP-12%TS), indicating that the THP at a higher solids content could alleviate such a mass transfer limitation by disintegrating sludge flocks 20 and thereby increasing the methane yield up to 62% compared to the corresponding control (Control-12%TS) (Figure S1). Also, the THP enhanced the methane production by ∼10% for samples with 4 and 8% TS (THP-4%TS and THP-8%TS) compared to their respective controls (Control-4%TS and Control-8%TS).…”

El compostaje de cáscara de Musa paradisiaca L. para la producción de biogás y biometano como estrategia de preservación de la salud ambiental

“…También se ha demostrado que los métodos de pretratamiento, como la preparación del sustrato, la solubilización mecánica en combinación con el tratamiento térmico a baja temperatura, afectan el rendimiento del biogás. En procesos de digestión anaeróbica con lodos de aguas residuales consiguiente la aceleración de la digestión anaeróbica (Ahn & Chang, 2021). En el caso de residuos que contengan una gran cantidad de materia leñosa con un alto contenido de lignina, se requieren tiempos más largos para lograr la producción de biogás deseada.…”

Current Status and Review of Waste-to-Biogas Conversion for Selected European Countries and Worldwide

“…Pretreatment, co-digestion, bioaugmentation, biohythane, temperature, organic loading rate and reactor design are some of the ways to increase biogas yield [89]. It has also been shown that pretreatment methods, such as substrate preparation, mechanical solubilisation in combination with low-temperature heat treatment, affect biogas yield in AD processes with wastewater sludge because of a higher ability to dissolve sludge and consequent acceleration of anaerobic digestion [90]. In the case of waste containing a large amount of woody matter with a high lignin content, longer times are required to achieve the desired biogas production.…”