Remediation of dyes in textile effluent: a critical review on current treatment technologies with a proposed alternative

http://repositorium.sdum.uminho.pt/bitstream/1822/9716/1/Angelidaki_WST059050927%5b1%5d.pdf

Defining the biomethane potential (BMP) of solid organic wastes and energy crops: a proposed protocol for batch assays.

Optimisation of the anaerobic digestion of agricultural resources.

Review paper on current technologies for decolourisation of textile wastewaters: Perspectives for anaerobic biotechnology

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

Anaerobic digestion of olive oil mill wastewaters

This work reviews the existing methodologies for assessing microbial activity and inhibition under anaerobic conditions. The anaerobic digestion process consists of several metabolic steps–the Anaerobic Digestion Model No. 1 (ADM1) has attempted to describe these steps in the form of a mathematical model with the intention of providing a reference base for all further efforts in the modelling of anaerobic processes. The existence of a reference point for modelling has highlighted the fact that there is a lack of coherence between the many different methodologies for experimentally assessing anaerobic activity and inhibition. A working group of the International Water Association was recently founded to harmonise the existing methodologies with the ultimate intention of developing a unified reference procedure– a primary objective of the group will be the establishment of a standard terminology in the field of anaerobic digestion, activity and inhibition assessment. Secondly, it will compare the existing methodologies and develop standard protocols for assessing the kinetic parameters (e.g. maximum uptake rate, half-saturation constant) of anaerobic processes that may be entered directly into ADM1 and its successors. This paper revises and enlarges a contribution presented by the authors at the workshop “Harmonisation of anaerobic biodegradation, activity and inhibition assays” (Ligthart & Nieman 2002, Proc. workshop held in Orta (Italy) June 7–8, 2002) and aims to promote a clear understanding of the currently established methodology. Numerous methods have been developed over the past 30 years, since Van den Berg et al. (1974, Biotechnol Bioeng 16(11)– 1459–1469) measured methanogenic activity, by using a manometric device equipped with a photoelectric sensor to quantify the gas production. Methanogenesis is often the rate limiting step of the entire process and since the quantification of gas flowrate is relatively easy to perform, most of the methods reported in literature monitor the production of biogas. These methods can be termed volumetric or manometric methods, as the volume of biogas produced or the pressure increase due to gas production inside a close vessel are assessed, respectively. However, this same concept can be employed to assess activity or inhibition of individual metabolic steps preceding the methanogenic one, providing that they are rate limiting for the whole process. The reliability of activity assessment through gas measurement has been proven to be strongly dependent on the equilibrium between liquid and gas phase in a closed vessel. This can be influenced by many factors, e.g. the amount and characteristics of the test substrate; the concentration of the biomass; the gas-to-liquid ratio– all these aspects will need to be addressed in the standard procedure. Other direct or indirect methods, targeting physico-chemical or microbiological parameter exist and have been investigated by many authors. Besides the interest for research purposes, the definition of reference methods to assess activity and inhibition can be of great interest for engineers, both phy. Specific reference procedures might be needed for particular applications, e.g. the (kinetic) study of rate limiting microbial steps and might require ad-hoc methodologies to be devised. A microbiological technique such as FISH, coupled with microsensors have been reported to have a great potential in the near future.

Alberto Rozzi

Papers

Anaerobic digestion of olive oil mill wastewaters

Methods of assessing microbial activity and inhibition under anaerobic conditions: a literature review

Phosphorus and Nitrogen Removal in Moving-Bed Sequencing Batch Biofilm Reactors

Textile wastewater reuse in northern italy (COMO)

Influence of c:n ratio on the start-up of up- flow anaerobic filter reactors