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

Leu-M

Optimisation of the anaerobic digestion of agricultural resources.

The ensuing mechanical response to stressing or straining a structured liquid results in various viscoelastic phenomena, either in the linear region where the microstructure responds linearly with respect to the stress and strain but does not itself change, or in the nonlinear region where the microstructure does change in response to the imposed stresses and strains, but does so reversibly. The complication of thixotropy arises because this reversible, microstructural change itself takes time to come about due to local spatial rearrangement of the components. This frequently found time-response of a microstructure that is itself changing with time makes thixotropic, viscoelastic behaviour one of the greatest challenges facing rheologists today, in terms of its accurate experimental characterisation and its adequate theoretical description. Here a history of thixotropy is given, together with a description of how it is understood today in various parts of the scientific community. Then a mechanistic description of thixotropy is presented, together with a series of applications where thixotropy is important. A list of different examples of thixotropic systems is then given. Finally the various kinds of theories that have been put forward to describe the phenomenon mathematically are listed.

Thixotropy—a review

http://www.bashanfoundation.org/gmaweb/pdfs/P-removal.pdf

Recent advances in removing phosphorus from wastewater and its future use as fertilizer (1997-2003).

Mesophilic anaerobic digestion of waste activated sludge: influence of the solid retention time in the wastewater treatment process

Phosphate removal in anaerobic liquors by struvite crystallization without addition of chemicals: Preliminary results

The paper presents the results of two full-scale applications of the anaerobic co-digestion process of waste activated sludge together with the organic fraction of municipal solid wastes. The experiences were carried out at Viareggio and Treviso wastewater treatment plants (Italy). In the first plant, 3 tons per day of source sorted OFMSW were co-digested with waste activated sludge, increasing the organic loading rate from 1.0 to 1.2 kgTVS/m 3 d. This determined a 50% increase in biogas production. At Treviso WWTP, which has been working for 2 years, some 10 tons per day of separately collected OFMSW are treated using a low-energy consumption sorting line, which allows the removal of 99% and 90% of metals and plastics respectively. In these conditions, the biogas yield increased from 3,500 up to 17,500 m 3 /month. Industrial costs were evaluated less than 50 € per ton of organic waste, while the payback time was calculated as two years.

Paolo Battistoni

Papers

Mesophilic anaerobic digestion of waste activated sludge: influence of the solid retention time in the wastewater treatment process

Phosphate removal in anaerobic liquors by struvite crystallization without addition of chemicals: Preliminary results

Anaerobic codigestion of waste activated sludge and OFMSW: the experiences of Viareggio and Treviso Plants (Italy)

Anaerobic codigestion of waste activated sludge and OFMSW: the experiences of viareggio and treviso plants (Italy).

Struvite crystallization: a feasible and reliable way to fix phosphorus in anaerobic supernatants