Vegetable waste treatment: comparison and critical presentation of methodologies

Vegetable industries have been considered responsible for a great amount of pollution; hence, there has been a strong need for the optimization of vegetable waste treatment systems. The currently employed systems are numerous and fall in the following large categories; thermal processes, evaporation, membrance processes, anaerobic digestion, anaerobic co-digestion, biodiesel spraying, combustion, transesterification, coagulation, and composting. Respective methodologies in conjunction with waste treatment methods were presented per waste treatment method. The comparative presentation of the various vegetable waste treatment methodologies showed that though anaerobic digestion stands for the most enviromentally friendly technique, its required longer treatment time in conjuction with its weakness to deal with elemental contaminants makes imperative the employment of a second alternative technique which could either be a membrance process (low energy cost, reliability, reduced capital cost) or a coagulation/flocculation method because of its low cost and high effectiveness. Biogas production appears to be another promising and energy effective waste treatment method. On the other hand, methods like distillation and ozonation (high cost) and electrolysis (experimental level) have not been employed in the field. Finally, new waste management technologies have been described.     

Corn and rice waste: a comparative and critical presentation of methods and current and potential uses of treated waste

Although corn and rice waste can be hardly classified among the most hazardous waste, their treatment is very important in view of the great volume of waste materials involved. In this review article, an update is provided for most of the waste treatment techniques (composting, pyrolysis, gasification, combustion) used to alter the physical, chemical or biological character of the waste, to reduce its volume and/or toxicity and to make the waste safer for disposal. Furthermore, all current and potential uses of treated corn and rice waste such as fertilisers, biomass and biogas/biofuel are summarised. Four comprehensive tables and six figures provide a thorough presentation of both waste treatment methods (characteristics, advantages and disadvantages) and uses of treated corn and rice waste.     

Wheat, barley and oat waste: a comparative and critical presentation of methods and potential uses of treated waste

Wheat waste stands for one of the most important cereals both in view of its nutritive value and its high waste volume, although the latter is not considered among the most polluting source of wastes. However, it is of great importance to optimise the conversion of wheat, barley and oat waste into useful materials such as biomass, biogas/biofuel, animal feed and composting. Advantages and disadvantages and effectiveness per method (incineration, combustion, composting) are summarised by means of six comprehensive tables and six figures. It appears that the method with the greatest potential is the one aiming at conversion of wheat waste into biomass or biogas in view of the energy problems and the extended pollution of the environment due to release of carbon dioxide.     

Olive oil authentication: A comparative analysis of regulatory frameworks with especial emphasis on quality and authenticity indices,and recent analytical techniques developed for their assessment. A review

Over the last decades, olive oil quality and authenticity control has become an issue of great importance to consumers, suppliers, retailers, and regulators in both traditional and emerging olive oil producing countries, mainly due to the increasing worldwide popularity and the trade globalization of this product. Thus, in order to ensure olive oil authentication, various national and international laws and regulations have been adopted, although some of them are actually causing an enormous debate about the risk that they can represent for the harmonization of international olive oil trade standards. Within this context, this review was designed to provide a critical overview and comparative analysis of selected regulatory frameworks for olive oil authentication, with special emphasis on the quality and purity criteria considered by these regulation systems, their thresholds and the analytical methods employed for monitoring them. To complete the general overview, recent analytical advances to overcome drawbacks and limitations of the official methods to evaluate olive oil quality and to determine possible adulterations were reviewed. Furthermore, the latest trends on analytical approaches to assess the olive oil geographical and varietal origin traceability were also examined.