Wastewater-grown microalgae biomass as a source of sustainable aviation fuel: Life cycle assessment comparing hydrothermal routes.

The present paper compared, through life cycle assessment (LCA), the production of aviation biofuel from two hydrothermal routes of microalgae cultivated in wastewater. Hydrothermal liquefaction (HTL) and gasification followed by Fischer-Tropsch synthesis (G + FT) were compared. Both routes included biomass production, hydrotreatment for biofuel upgrading, and product fractionation. Secondary data obtained from the literature were used for the cradle-to-gate LCA. G + FT had a higher impact than HTL in the 18 impact categories assessed, with human carcinogenic toxicity exerting the most harmful pressure on the environment. The catalysts were the inputs that caused the most adverse emissions. The solvent used for bio-oil separation also stood out in terms of impacts. In HTL, emissions for global warming were -51.6 g CO2 eq/MJ, while in G + FT, they were 250 g CO2 eq/MJ. At the Endpoint level, HTL resulted in benefits to human health and ecosystems, while G + FT caused environmental damage in these two categories, as well as in the resources category. In the improvement scenarios, besides considering solid, aqueous, and gaseous products as co-products rather than just as waste/emissions, a 20% reduction in catalyst consumption and 90% recovery were applied. Thus, in HTL, 39.47 kg CO2 eq was avoided, compared to 35.44 kg CO2 eq in the base scenario. In G + FT, emissions decreased from 147.55 kg CO2 eq to the capture of 8.60 kg CO2 eq.

Aviation fuel based on wastewater-grown microalgae: Challenges and opportunities of hydrothermal liquefaction and hydrotreatment.

The current technical issues related to the conversion of algal biomass into aviation biofuel through hydrothermal liquefaction (HTL) and the upgrading of bio-oil through hydrotreatment have been reviewed and consolidated. HTL is a promising route for converting microalgae into sustainable aviation fuel (SAF). However, HTL must be followed by the hydrotreatment of bio-oil to ensure that its composition and properties are compatible with SAF standards. The fact that microalgae offer the possibility of recovering wastewater treatment resources not only makes them more attractive but also serves as an incentive for wastewater treatment, especially in countries where this service has not been universalized. The combination of SAF and wastewater treatment aligns with the Sustainable Development Goals of the United Nations, representing an advantageous opportunity for both aviation and sanitation. In this context, the utilization of HTL by-products in the concept of a biorefinery is essential for the sustainability of aviation biofuel production through this route. Another important aspect is the recovery and reuse of catalysts, which are generally heterogeneous, allowing for recycling. Additionally, discussions have focused on biomass pretreatment methods, the use of solvents and catalysts in HTL and hydrotreatment reactions, and the operational parameters of both processes. All these issues present opportunities to enhance the quantity and quality of bio-oil and aviation biofuel.

Determination of the spatial susceptibility to Yellow Fever using a multicriteria analysis

BACKGROUND The outbreak of sylvatic Yellow Fever (SYF) in humans during 2016-2017 in Brazil is one of the greatest in the history of the disease. The occurrence of the disease in areas with low vaccination coverage favoured the dissemination of the disease; therefore, it is necessary to identify the areas vulnerability to the YF virus (YFV) to assist in the adoption of preventive measures. OBJECTIVE To correlate the physical-environmental elements associated with the occurrence of SYF in humans via a multicriteria analysis. METHODS For the multicriteria analysis, preponderant elements related to SYF occurrences, including soil usage and coverage, temperature, precipitation, altitude, mosquito transmitters, and non-human primate occurrence areas, were considered. The results were validated by assessing the correlation between the incidence of SYF and the vulnerable areas identified in the multicriteria analysis. RESULTS Two regions with different vulnerability to the occurrence of the disease were identified in the multicriteria analysis, with emphasis on the southern areas of the state of São Paulo northeast areas of Minas Gerais, and the entire states of Rio de Janeiro and Espírito Santo. The map of SYF vulnerability obtained in the multicriteria analysis coincides with the areas in which cases of the disease have been recorded. The regions that presented the greatest suitability were in fact the municipalities with the highest incidence. MAIN CONCLUSIONS The multicriteria analysis revealed that the elements that were used are suited for and consistent in the prediction of the areas that are vulnerable to SYF. The results obtained indicate the proximity of the areas that are most vulnerable to the disease to densely populated areas where an Aedes aegypti infestation was observed, which confers a high risk of re-urbanisation of YF.

Microalgae biofilm in soil: Greenhouse gas emissions, ammonia volatilization and plant growth.

Microalgal biofilm in soils represents an alternative fertilization method for agricultural sustainability. In the present study, greenhouse gas emission, soil ammonia volatilization, and the growth of Pennisetum glaucum were evaluated under the effect of a microalgal biofilm, commercial urea, and a control (without application of a nitrogen source). CH4 emissions were equal for the three treatments (p>0.05). CO2 emissions significantly increased in microalgal biofilm treatment (p<0.01), which was also responsible for the highest N2O emissions (p<0.01). The ammonia (NNH3) volatilization losses were 4.63%, 18.98%, and 0.82% for the microalgal biofilm, urea, and control treatments, respectively. The main differences in soil characteristics were an increase in nitrogen and an increase in cation exchange capacity (p<0.01) caused by the algal biomass application to the soil. The soil organic matter content significantly differed (p<0.05) among the three treatments, with the microalgal biofilm treatment having the greatest increase in soil organic matter. Significant differences were observed for shoot dry matter mass and nitrogen content in the plants from both treatments where nitrogen sources were applied. All treatments differed from each other in leaf dry matter mass, with the urea treatment increasing the most. Chlorella vulgaris was the dominant microalgal specie in the soil.

Effect of solar radiation on the lipid characterization of biomass cultivated in high-rate algal ponds using domestic sewage.

The objective of this paper is to compare the lipid content and composition ofbiomass produced by a consortium of microalgae and bacteria, cultivated under different solar radiation intensities and tropical conditions in pilot-scale high-rate ponds (HRPs) using domestic sewage as culture medium. The treatment system consisted of an upflow anaerobic sludge blanket reactor followed by UV disinfection and six HRPs covered with shading screens that blocked 9%, 18%, 30%, 60% and 80% of the solar radiation. The total lipid content does not vary significantly among the units, showing a medium value of 9.5%. The results show that blocking over 30% of the solar radiation has a negative effect on the lipid productivity. The units with no shading and with 30% and 60% of solar radiation blocking have statistically significant lipid productivities, varying from 0.92 to 0.96 gm(-2) day(-1). Besides radiation, other variables such as volatile suspended solids and chlorophyll-a are able to explain the lipid accumulation. The lipid profile has a predominance of C16, C18:1 and C18:3 acids. The unsaturation of fatty acids increases with the reduction in solar radiation. On the other hand, the effect of polyunsaturation is not observed, which is probably due to the presence of a complex and diverse biomass.

Tratamento de esgotos sanitários em sistemas reatores UASB/wetlands construídas de fluxo horizontal: eficiência e estabilidade de remoção de matéria orgânica, sólidos, nutrientes e coliformes / Domestic wastewater treatment in UASB-horizontal flow constructed wetlands systems: organic matter, solids, nutrients and coliforms removal

Este trabalho apresentou os resultados de um estudo realizado durante 19 meses sobre o comportamento de wetlands construídas na remoção de matéria orgânica, sólidos, nutrientes e coliformes, em unidades em escala piloto de fluxo horizontal, subsuperficial e superficial, com tempo de detenção hidráulica entre 1,3 a 5,3 dias, operando como pós-tratamento de efluentes de reatores UASB (esgotos sanitários). A remoção de matéria orgânica e de sólidos mostrou-se elevada e estável, com eficiências médias de 70, 80 e 60 por cento para SST, DBO5 e DQO, respectivamente. A remoção de nutrientes, após início promissor, mostrou-se instável e aparentemente influenciada pela temperatura. O sistema de tratamento revelou elevado potencial de remoção de coliformes, embora com variações relativamente amplas ao longo do período de operação: ≈ 2 log10 de remoção de coliformes totais e 2-4 log10 de remoção de Escherichia coli.

This work presented the results of a 19-month study on the performance of constructed wetlands in terms of organic matter, solids, nutrients and coliforms removal in pilot scale unities with horizontal, subsurface and surface flow, with hydraulic retention time from 1.3 to 5.3 days, as post-treatment of UASB effluents (domestic wastewater). Organic matter and solids were effectively and consistently removed, with average values of 70, 80 and 60 percent for TSS, BOD5 and COD, respectively. Nutrients removal, after a promising start up, became unstable and apparently influenced by temperature. The treatment system has also shown high potential to remove coliforms, although with relatively wide variations over the study period: ≈ 2 log10 reduction of total coliforms and 2-4 log10 reduction of Escherichia coli.

Estudo de indicadores de saúde ambiental e de saneamento em cidade do Norte do Brasil / Study of indicators of environmental health and sanitation in Northern city of Brazil

A qualidade de vida de uma população está diretamente relacionada com a infraestrutura urbana em que a mesma está inserida. Nesse sentido, o objetivo do estudo foi avaliar a saúde pública da área urbana do município de Tucuruí no Pará, sob o ponto de vista das condições do saneamento ambiental e a composição de um sistema com menor quantidade de variáveis para discriminar áreas com distintos níveis sanitário-ambientais, e relacionar esses indicadores com a ocorrência de agravos à saúde nessas áreas. O município de Tucuruí foi selecionado para a área de estudo devido à deficiência de sua infraestrutura sanitária, alta taxa de crescimento da população, e a forte incidência de doenças tropicais relacionadas diretamente com as condições sanitárias.

The quality of life from a population is directly related to urban infrastructure on which it is embedded. Accordingly, the objective of the study was to evaluate the public health in the municipality of Tucuruí in Pará, under conditions of environmental sanitation to the composition of a system with a smaller number of variables to discriminate areas with different levels of sanitary and environmental health, and relate these indicators with the occurrence of diseases related to health in these areas. The municipality of Tucuruí was selected for the study area due to the deficiency of their health infrastructure, high rate of population growth, and high incidence of tropical diseases directly related to the health conditions.

Identificação de áreas alternativas para disposição de resíduos sólidos na região do Baixo Ribeira do Iguape - SP / Identification of alternative areas for solid waste disposal in Baixo Ribeira do Iguape - SP

Este trabalho teve por objetivo a proposição de cenários para o equacionamento da disposição de resíduos sólidos gerados por áreas urbanas da região do Baixo Ribeira de Iguape, localizado no estado de São Paulo. Utilizou-se a análise multicritério, que requer a identificação de critérios que podem ser restrições e fatores. Como critérios de agregação optou-se pela Combinação Linear Ponderada e pela Média Ponderada Ordenada. Para cada um dos municípios calculou-se a área necessária para a disposição final de seus resíduos sólidos. Os resultados mostraram que a melhor área para o município de Cajati está localizada a aproximadamente 3,0km da sede do mesmo, para Jacupiranga a 2,7km e para Pariqüera-Açu a 2,4km. A metodologia mostrou-se adequada ao propósito em questão, levando-se em consideração 18 fatores e restrições influentes no processo de decisão.

This paper addresses the proposition of scenarios for the equation of the disposal of solid residues generated by urban areas of the region of the Baixo Ribeira de Iguape, located in the São Paulo State, Brazil. Multicriterion analysis requiring identification of criteria that can play restrictions and factors roles were used. Aggregation Criteria was represented by the Weighed Linear Combination and the Ordered Weighed Mean. For each one of the selected cities it was calculated the required area for the final disposal of its solid residues. The results had shown that the best area for the city of Cajati is located approximately 3,0 km of its headquarters, for Jacupiranga 2,7 km and for Pariqüera-Açu 2,4 km. The applied methodology revealed adequate to the objective of this research, taking into account 18 influential factors and restrictions in the decision process.