A conceptual design of an industrial production plant for activated carbon was developed to process 31.25 tons/day of industrial waste nutshells as the raw material and produce 6.6 ton/day of activated carbon using steam as an activation agent. The design considered the cost of the main equipment, the purchase price of the nutshells, basic services, and operation. A sensitivity analysis was developed, considering the price of the finished product and the volume of raw material processing varied up to ±25%. Furthermore, the total annual cost of the product was determined based on the production of 2100 tons/year of activated carbon. Two cash flows were developed and projected to periods of 10 years and 15 years of production, using a tax rate of 27%, a low discount rate (LDR) of 10% per year, and without external financing. For a 10-year production project, the net present value (NPV) was USD 2,785,624, the internal return rate (IRR) 21%, the return on investment (ROI) 25%, and the discounted payback period (DPP) after the fifth year. Considering a project with 15 years of production, the NPV was USD 4,519,482, the IRR at 23%, the ROI 24%, and the DPP after the fifth year of production.

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Most developing countries lack sufficient legal and management infrastructure to dispose of urban solid waste (USW). The continuous increase of USW generation requires evaluating different treatments for developing countries based on the life cycle assessment methodology to compare the environmental impact by reducing greenhouse gases and leachate. Hydrothermal carbonization (HTC) and gasification processes are presented as potential solutions for USW treatment due to their efficiency in producing energy for local requirements. This study aimed to compare both technologies for Temuco and Padre Las Casas cities in Southern Chile that show severe air pollution and USW management problems. The results indicated that gasification had a better environmental performance than HTC when the conversion of 1 ton of organic fraction USW was analyzed. However, since HTC achieved higher energy efficiency, it had a lower environmental impact than gasification, considering the production of 1 MWh. For a definitive choice of the technology to be used, it is necessary to compare other variables, including economic and social aspects, to provide a holistic perspective.

This work analyzes the relationship between short-term exposure to fine particulate matter and its incidence of respiratory and cardiorespiratory diseases. It involved the socioeconomic status of the population distributed in representative areas of Santiago de Chile, the capital city of Chile. The data used were collected from monitoring stations of fine particulate matter concentrations, classification of cardio-respiratory diseases, and the annual age distribution of the population in the representative areas of this megacity. Also, morbidity and mortality data and the distribution of the forecast of health by geographic zones within the Metropolitan Region were variables of input. The relative risk results showed that the level of risk from exposure to air pollution is not defined solely by the level of exposure to the pollutant when crossing the information considered. Therefore, the age distribution or quality of life of the population will define the susceptibility of this, being able to increase the risk of becoming ill or dying by being exposed to air pollution. This work showed that the exposed results serve as input data for the realization of studies in this area, regarding the cost-benefit that would be obtained by reducing pollutant emissions to the atmosphere, as well as valuable information to develop better air quality management policies.

The effect of magnesium chloride as an additive of hydrothermal carbonization (HTC) of lignocellulosic biomass (Pinus radiata sawdust) was studied. The HTC tests were carried out at fixed conditions of temperature and residence time of 220 °C and 1 h, respectively, and varying the dose of magnesium chloride in the range 0.0–1.0 g MgCl2/g biomass. The carbonized product (hydrochar) was tested in order to determine its calorific value (HHV) while using PARR 6100 calorimeter, mass yield by gravimetry, elemental analysis using a LECO TruSpec elemental analyzer, volatile matter content, and ash content were obtained by standardized procedures using suitable ovens for it. The results show that using a dose of 0.75 g MgCl2/g biomass results in an impact on the mass yield that was almost equal to change operating conditions from 220 to 270 °C and from 0.5 to 1 h, without additive. Likewise, the calorific value increases by 33% for this additive dose, resulting in an energy yield of 68%, thus generating a solid fuel of prominent characteristics.

Wildfires generate large amounts of atmospheric pollutants yearly. The development of an emissions inventory for this activity is a challenge today, mainly to perform modeling of air quality. There are free available databases with historical information about this source. The main goal of this study was to process the results of biomass burning emissions for the year 2014 from the Global Fire Assimilation System (GFAS). The pollutants studied were the black carbon, the organic carbon, fine and coarse particulate matter, respectively. The inputs were pre-formatted to enter to the simulation software of the emission inventory. In this case, the Sparse Matrix Operator Kernel Emissions (SMOKE) was used and the values obtained in various cities were analyzed. As a result, the spatial distribution of the forest fire emissions in the Southern Hemisphere was achieved, with the polar stereographic projection. The highest emissions were located in the African continent, followed by the northern region of Australia. Future air quality modeling at a local level could apply the results and the methodology of this study. The biomass burning emissions could add a better performance of the results and more knowledge on the effect of this source.

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