The Combined Activated Sludge-Anaerobic Digestion Model (CASADM) quantifies the effects of recycling anaerobic-digester (AD) sludge on the performance of a hybrid activated sludge (AS)-AD system. The model includes nitrification, denitrification, hydrolysis, fermentation, methanogenesis, and production/utilization of soluble microbial products and extracellular polymeric substances (EPS). A CAS...

Adsorption of ammonia from anaerobic digester effluent by magnetically modified zeolite (MMZ) has been investigated using a batch technique and comparison of adsorption isotherm equations. Adsorption isotherm models were utilized to describe the equilibrium isotherms and the isotherm constants were calculated. The sorption of ammonia follows Langmuir, Freundlich and Dubinin-Radushkevich (D-R) m...

This paper presents a saturated proportional controller that achieves depollution of wastewater in a continuous anaerobic digester. This goal is reached by defining a region of the state-space where the depollution is achieved and forcing attractivity and invariance of this region. The control variable is the dilution rate and the controlled variable is a linear combination (S(lambda)) of the s...

Anaerobic digestion (AD) is a complex biological system which can be affected by several operational problems. Among them, biological foaming is one of the most difficult to deal with. It has many effects, such as causing gas pipe clogging and probe failures, and it can affect mixing devices, etc. Since the mechanisms involved in biological foaming development are not fully understood, it is no...

This review is a summary of different aspects of the design and operation of small-scale, household, biogas digesters. It covers different digester designs and materials used for construction, important operating parameters such as pH, temperature, substrate, and loading rate, applications of the biogas, the government policies concerning the use of household digesters, and the social and envir...

Anaerobic digestion (AD) is an efficient and sustainable way of using organic carbon from residual biomass and organic waste for the production of renewable energy, while simultaneously recycling nutrients and cleaning up waste streams. The process relies on complex microbial communities comprised of diverse functional guilds; these communities have manifold metabolic pathways and interactions....

In this paper, a simple and rapid method was developed in order to assess in comparative tests the production of binary biogas mixtures containing CO(2) and another gaseous compound such as hydrogen or methane. This method was validated and experimented for the characterisation of the biochemical hydrogen potential of different pure strains and mixed cultures of hydrogen-producing bacteria (HPB...