Inhibition of anaerobic digestion process: A review

Anaerobic digestion of organic solid wastes. An overview of research achievements and perspectives

Optimisation of the anaerobic digestion of agricultural resources.

With the rising demand for renewable energy and environmental protection, anaerobic digestion of biogas technology has attracted considerable attention within the scientific community. This paper presents a comprehensive review of research achievements on anaerobic digestion developments for biogas production. The review includes a discussion of factors affecting efficiency (temperature, pH, C/N ratio, OLR and retention time), accelerants (greenery biomass, biological pure culture and inorganic additives), reactors (conventional anaerobic reactors, sludge retention reactors and anaerobic membrane reactors) and biogas AD processes (lignocellulose waste, municipal solid waste, food waste, livestock manure and waste activated sludge) based on substrate characteristics and discusses the application of each forementioned aspect. The factors affecting efficiency are crucial to anaerobic digestion, because they play a major role in biogas production and determine the metabolic conditions for microorganism growth. As an additive, an accelerant is not only regarded as a nutrient resource, but can also improve biodegradability. The focus of reactor design is the sufficient utilization of a substrate by changing the feeding method and enhancing the attachment to biomass. The optimal digestion process balances the optimal digest conditions with the cost-optimal input/output ratio. Additionally, establishment of theoretical and technological studies should emphasize practicality based on laboratory-scale experiments because further development of biogas plants would allow for a transition from household to medium- and large-scale projects; therefore, improving stability and efficiency are recommended for advancing AD research.

Review on research achievements of biogas from anaerobic digestion

Ammonia inhibition in anaerobic digestion: A review

Anaerobic digestion is a well established process for treating many types of organic waste, both solid and liquid. As such, the digestion of cattle slurries and of a range of agricultural wastes has been evaluated and has been successful. Previous batch studies have shown that based on volatile solids (VS) reduction, total methane production and methane yield, co-digestions of cattle slurry (CS) with fruit and vegetable wastes (FVW) and with chicken manure (CM) were among the more promising combinations. A continuously stirred tank reactor ( 18 litres ) was used as a mesophilic (35°C) anaerobic reactor to examine the effect of adding the FVW and CM to a system which was digesting CS. The retention time was kept at 21 days and the loading rate maintained in the range 3.19– 5.01 kg VS m −3 d −1 . Increasing the proportion of FVW from 20% to 50% improved the methane yield from 0.23 to 0.45 m 3 CH 4 kg −1 VS added, and caused the VS reduction to decrease slightly. Increasing the proportion of chicken manure in the feed caused a steady deterioration in both the criteria for judging digester performance. This appeared to be caused by ammonia inhibition.

Continuous co-digestion of cattle slurry with fruit and vegetable wastes and chicken manure

Co-digestion of waste organic solids: batch studies

A kinetic study of the anaerobic digestion of ice-cream wastewater

Anaerobic digestion of cattle slurry has become a well established practice. In recent years disposal of waste milk in the UK has been the cause of many pollution incidents. This paper describes the co-digestion of cattle slurry and waste milk under shock loading conditions in 1 dm 3 laboratory digesters. Methane concentration in the biogas of all digesters receiving waste milk additions initially dropped, but quickly recovered to above previous levels. The methane production rate (dm 3 methane day -1 ) was most elevated in those digesters receiving the greatest loading of waste milk; however, initial depression of biogas methane concentration was also greatest in this system.

K. Thayanithy

Papers

Continuous co-digestion of cattle slurry with fruit and vegetable wastes and chicken manure

Co-digestion of waste organic solids: batch studies

A kinetic study of the anaerobic digestion of ice-cream wastewater

Co‐Digestion of Cattle Slurry and Waste Milk under Shock Loading Conditions

An examination of the continuous anaerobic co-digestion of cattle slurry and fish offal