Aerobic Granular Sludge as a Substrate in Anaerobic Digestion—Current Status and Perspectives

Abstract

Even though many wastewater treatment systems have been applied so far, there is still a need to develop methods, the implementation of which are technologically and economically justified. The aerobic granular sludge (AGS) method, which has been developed for several years, may represent an alternative to traditional technologies. One of the barriers to AGS deployment is the limited knowledge on the determinants and efficiency of the anaerobic digestion (AD) of AGS, as little research has been devoted to it. Therefore, the aim of the present paper is to summarize the current state of knowledge on the subject, including a review of technological conditions, process performance, and AGS parameters that can impact AD, and currently used pre-treatment methods. The anaerobic stabilization performance of AGS is compared against conventional activated sludge (CAS). The paper also identifies avenues for further research and practical implementations to further optimize the process and to determine whether AD is viable in full-scale plants.

Methane Production from Confectionery Wastewater Treated in the Anaerobic Labyrinth-Flow Bioreactor

“…Due to the high organic content of confectionery effluents, the new construction of the anaerobic reactor is suitable to treat such kinds of sewage. Anaerobic digestion takes place in four metabolic phases (hydrolysis, acidogenesis, acetogenesis, and methanogenesis), and each of them requires specific conditions for a smooth and efficient run [62,63]. The most popular reactors used in full-scale to treat confectionery sewage are single-stage tank biogas reactors, such as UASB and EGSB reactors, in which all phases of anaerobic digestion are conducted in parallel in one digestion chamber.…”

Biotechnological Valorization of Waste Glycerol into Gaseous Biofuels—A Review

“…Each step of the digestion is mediated by specialized microorganisms that hydrolyze polymeric substances through enzyme action [49][50][51]. They are further broken down into fatty acids, alcohols, H 2, and CO 2 [52]. AD is a process that consists of the following steps: hydrolysis, acidogenesis, acetogenesis, and methanogenesis.…”

Application of Hydrodynamic Cavitation in the Disintegration of Aerobic Granular Sludge—Evaluation of Pretreatment Time on Biomass Properties, Anaerobic Digestion Efficiency and Energy Balance

“…However, remediable weaknesses, technical difficulties and emerging operational problems are still being identified [6]. Solutions are being sought to improve the methods of biodegradation of pollutants based on AGS, as well as technologies for the processing, stabilisation and neutralisation of this type of sewage sludge [7]. The direction is to improve economic profitability and technological efficiency, which should additionally increase the popularisation and dissemination of AGS-based solutions.…”