Understanding the dependence of biochar properties on different types of biomass.

Owing to the diversity of biomasses and many variables in pyrolysis process, the property of biochar from varied biomass feedstock or even same biomass could differ significantly. Since the property of biochar governs the further application of biochar, this review paid particular attention to the correlation between the nature of biomass feedstock and the specifications of biochar in terms of yield, elemental composition, pH, functionalities, heating value, pore structures, morphologies, etc. The property of the biochar from the pyrolysis of cellulose, hemicellulose, lignin, woody biomass (pine, mallee, poplar, acacia, oak, eucalyptus and beech), bark of woody biomass, leaves of woody biomass, straw, algae, fruit peels, tea waste was compared and summarized. In addition, the differences of the biochar of these varied origins were also analyzed. The remaining questions, about the correlation of biomass nature with biochar characteristics, to be further investigated are analyzed in detail. The deduced information about the relationship of the nature of biochar and biomass feedstock as well as key pyrolysis parameters is of importance for further development of the methods for tailoring or production of the biochar of desirable properties. The results from this study could be interesting technically and commercially for the technology developer using biochar as the source of carbon in different applications.

Decreasing environmental impact of landfill leachate treatment by MBR, RO and EDR hybrid treatment.

A prototype pilot plant testing for a novel complete treatment strategy for landfill leachate aimed to decrease its environmental impact was studied. Pre-treatment of leachate was performed by means of a membrane biore-actor (MBR) decreasing inorganic carbon concentration by 92 ± 8% and achieving N removals of 85%. Suspended solids removal in the MBR >99.9% conditioned leachate for the next membrane step. Spiral-would reverse osmosis (RO) regenerated membranes were used to treat the MBR effluent. This RO unit achieved a global recovery of 84% along with operation and rejections of >95% for most of the analyzed compounds. Since RO permeate did not meet discharge standards, promising results were obtained after a second RO pass was applied. The RO brine produced was further concentrated by an electrodialysis reversal (EDR) unit, achieving an averaged recovery of 67% throughout the operation. The average recovery of the whole pilot plant system was >90%. The reduction of global brine volume together with the use of regenerated membranes are key to the environmental impact of the process and contribute to closing the loop of the circular economy. Life Cycle Assessment (LCA), performed according to ILCD Handbook guidelines, demonstrated that proposed new treatment had lower environmental impact than conventional treatments currently used in landfill facilities. Concretely, for the nine impact categories evaluated, the proposed treatment presented an average impact reduction of 93% compared to an advanced oxidation system and an average reduction of 26% when compared to a conventional RO treatment.