Innovative Strategies for Ozone Treatment of Industrial Wastes: Hydrothermal Liquefaction of Surfactant Wastewater and Leacheate Evaporation

In this paper, ozonation is used as a pre-treatment for two different kinds of wastewaters. The first purpose is the study of the effect of ozonation on a landfill leachate treated by a reverse osmosis process prior a concentration step in an atmospheric evaporator. At first sight, an ozone treatment can supply three effects: Defoaming capacity, biocide effect, and pH acidifier to avoid the ammonia striping in the evaporation process. The second purpose of this paper is regarding hydrothermal liquefaction (HTL) of wastewaters. HTL can produce a liquid fuel, normally called crude-oil, alternative to fossil fuels, as well as other products of industrial interest (phenols, furfurals, etc.). The second objective is the study of the possible positive effect that a pre-treatment with ozone can have on the performance of the subsequent HTL. In this work, HTL is applied to liquid surfactant wastes obtaining up to 7% crude-oil yield, with a High Heating Value (HHV) higher than 8.000 cal/g. These results are compared with those obtained when an ozonation pre-treatment is applied before the HTL process. Ozone treatment shows a slight defoaming capacity for the leachate feed but don’t seem to show a significant difference in the HHV of the crude-oils obtained from liquid surfactant. However, there is a noticeable difference in the solid residue generated for this later. Less aggregates of solid particles and a weight reduction of 20% in the filtering step were obtained from ozonated liquid surfactants. The reduction of solid by-products is of great interest for dimensioning an industrial-scale HTL plant due to the problems that these solids can generate in pipes and valves

Valorization of unripe papaya for pectin recovery by conventional extraction and compressed fluids

The aim of the study was to establish a green protocol for pectin extraction from unripe papaya flour (UPF), comparing conventional acid hydrolysis (CONV) and compressed fluid extraction techniques, including Pressurized Hot Water Extraction (PHWE) and Enhanced Solvent Extraction (ESE). Highest pectin yields were achieved with ESE (216 ± 10.8 mg g−1) when CO2+H2O (20:80) + citric acid (0.05 mol L−1) was applied (40 MPa/80 °C/60 min/300–710 µm), similar to that obtained by CONV (202 ± 49.5 mg g−1) and PHWE (208.0 ± 9.4 mg g−1) using oxalic acid. UPF pectin presented an average galacturonic acid (GalA) content of 73% (w/w) and degree of esterification (DE) of 57.8%, and it was composed predominantly of galactose, glucose and rhamnose. This pectic substance has been shown to contain two main types of pectic chains: rhamnogalacturonan-I (RG-I, average 58%) proportionally higher than homogalacturonan (HG, average 28%). Compressed fluid extraction techniques allowed obtaining high quality pectin with similar composition to other commercial products.The authors thank the following organizations, which supported this project: Organization of American States (OAS), USA; Universidade Tecnológica Federal do Paraná (UTFPR-PG) Ponta Grossa Campus, Brazil; Coimbra Group of Brazilian Universities (GCUB)-PAEC, Brazil and the Pan American Health Organization (OPS)/WHO), USA. Additionally, the authors are deeply grateful to Hans Ulrich Endreβ (Herbstreith & Fox, Germany) for samples of standardized pectin and for analyses kindly carried out in his industry.Peer reviewe

Memorias del primer Simposio Nacional de Ciencias Agronómicas

Primer simposio nacional de Ciencias Agronómicas: El renacer del espacio de discusión científica para el Agro colombiano