Valorização agronómica/energética de lamas de ETAR

Mestrado em Engenharia do Ambiente - Instituto Superior de AgronomiaThis work aims to evaluate the use of 4 different sewage sludges as a fertilizer: mixed sewage sludge (primary+secondary sludge), dehydrated mixed sewage sludge; anaerobically digested sewage sludge and anaerobically digested sewage sludge treated with quicklime (CaO). Two aerobic incubations were performed with mixtures of sludge and the top layer of a Haplic Pdzol, at a rate equivalent to 10 ton dry matter ha- 1. During 140 days, the CO2-C emissions and the mineral N in soil were periodically measured. At the end of the incubation period, several soil properties were evaluated. The higher CO2-C emission was found in the mixed sludges while the anaerobic sludge presented the lower value. The treatment of anaerobic sludge with lime led to an increase of CO2-C emission and nitrogen mineralization from the sludge, indicating that lime treatment promoted more favorable conditions to sludge mineralization. At the end of the incubation period, sludge-amended soil had higher pH, more evident on the lime-treated sludge, and higher amounts of available nutrients, namely, nitrogen, phosphorus, potassium and calcium. The balance between applied carbon and C-CO2 emission, proved that sewage sludge increases carbon accumulation in soil

The antimicrobial properties of Moringa oleifera Lam. for water treatment: a systematic review

Plant extracts have been used as alternatives to the conventional chemical water treatment. Moringa oleifera Lam. is one of the plants used for this purpose due to its antimicrobial and coagulant properties. However, there is no systematization of Moringa’s application methodology. Different parts of the plant, extraction methods and concentrations can be applied to remove several pathogens present in contaminated drinking water. In the present work, reported Moringa applications with antimicrobial effect were systematically reviewed, in order to identify effective methodology(ies) for water treatment. Forty-nine articles were screened for: (1) part of the plant used, (2) extraction method, (3) extract concentration, (4) targeted pathogens, and (5) inhibition zone obtained. Nine articles complied with these criteria and were carefully analyzed; eight of them reported on leaf extracts and only one on seed extracts. Two approaches were used: analysis by pathogen and overall analysis. A total of eight different extraction methods were reported. Extract concentrations used ranged from 0.02 to 800 mg mL−1 and were tested on twenty pathogens. Our analysis revealed that none of such methods is effective against all the tested pathogens. However, leaf extracts obtained with distilled water or with 95% ethanol were the most effective ones for a higher number of pathogens such as Escherichia coli and, possibly, Vibrio cholerae. Moreover, Moringa’s extract concentration of 30 mg mL−1 obtained by the 95% ethanol extraction method was the most efficient. Findings suggest an effective procedure to use Moringa, reinforcing its importance as an environmentally friendly alternative for water treatment in areas lacking a water supply system.info:eu-repo/semantics/publishedVersio

Moringa as a household water purification method – community perception and pilot study in Guinea-Bissau

Background: Public perceptions of water-related issues are still under-researched topics. The current paper intends to explore a local community’s perceptions regarding household water purification (HWP) strategies, namely before and after trying a new method: moringa seeds powder (moringa-teabag). Methods: In September 2020, six focus group discussions (N = 65) assessing perceptions about the usefulness of Moringa oleifera Lam (Moringaceae) as a HWP method (before moringa-based HWP trials), and questionnaires (N = 104) evaluating successes and identifying difficulties (after one week of moringa-based HWP trials). Participants were all women aged over 18 years, living in Ondame, Biombo region, Guinea-Bissau. Data were analyzed using qualitative and quantitative approaches. Results: The focus group discussions revealed that people are aware of the fact that water can transmit diseases. Although certain persons showed concern about shallow well water safety, people generally underestimate the risk, as they trust tubewell water. Not everyone had an understanding of what water contamination is, or the concept of medical importance. Some respondents declared they use traditional methods such as boiling and bleach to treat water before drinking. However, those who reported no kind of treatment indicated reasons such as lack of time, cost, and bleach’s taste and smell. In the questionnaire, more than half of the participants (68%) reported treating water before consumption. Nevertheless, these results are not consistent with our field notes. Participants demonstrated a strong belief in the capacity of moringa-teabags to purify water and even consider them better or much better (81%) than other methods. Participants asked for more information on moringa-teabag for household water purification. Conclusion: More information on water treatment and water safety would help to raise public awareness about waterborne diseases. These findings could be used to promote greater adherence to moringa-based HWP as an alternative to household water treatment.info:eu-repo/semantics/publishedVersio

Quality assessment of three types of drinking water sources in guinea-bissau

The lack of access to safe drinking water causes important health problems, mainly in developing countries. In the West African country Guinea-Bissau, waterborne diseases are recognised by WHO as major infectious diseases. This study analysed the microbiological and physicochemical parameters of drinking water in the capital Bissau and its surroundings. Twenty-two sites belonging to different water sources (piped water, tubewells and shallow wells) were surveyed twice a day for three weeks, in both dry and wet seasons. Most of the microbiological parameters were out of the acceptable ranges in all types of water and both seasons and tended to worsen in the wet season. Moreover, in Bissau, the levels of faecal contamination in piped water increased from the holes to the consumer (tap/fountain). Several physicochemical variables showed values out of the internationally accepted ranges. Both well sources showed low-pH water (4.87–5.59), with high nitrite and iron levels in the wet season and high hexavalent chromium concentration in the dry season. The residual chlorine never reached the minimum recommended level in any of the water sources or seasons, suggesting a high risk of contamination. Results reveal a lack of quality in the three water sources analysed, coherent with the high number of diarrheal cases in the country. There is an urgent need to improve sanitarian conditions to reduce the disease burden caused by these waterborne illnesses.publishersversionpublishe

Effect of anaerobic digestion and lime stabilization on sewage sludge carbon and nitrogen mineralization

This work aims to evaluate the N and C mineralization in a Haplic Arenosol amended with 3 different sewage sludge: mixture of primary and secondary sewage sludge (MSS), anaerobically digested sewage sludge (DSS) and anaerobically digested sewage sludge treated with quicklime (LimeDSS). Two aerobic incubations, one to follow N mineralization and the other one to assess CO2 emissions, were performed during 140 days. MSS promoted soil N immobilization during the first days of incubation and higher CO2 emissions (46% of the applied C was lost), consequence of a high content of non-stabilized organic matter. In DSS there was nitrogen net mineralization but only 17% of the applied carbon was mineralized, showing that anaerobic digestion stabilized the sludge organic matter. Sewage sludge treatment with quicklime reduced its NH4+ content, but enhanced carbon (40%) and nitrogen (39.2%) mineralization after soil application. Anaerobic digested sewage sludge (DSS) seems to be the most interesting treatment, since it ensured a high level of available N to plants and a great contribution to C sequestra-tion in soil

Compositional features and biological activities of wild and commercial Moringa oleifera leaves from Guinea-Bissau

Moringa oleifera Lam. is a nutraceutical edible plant used to fight malnutrition in developing countries. This investigation describes the nutritional, chemical and bioactive assets of wild and commercially acquired M. oleifera leaves from Guinea-Bissau. Both samples presented significant differences in the contents of almost all the analysed parameters. Carbohydrates and proteins were the major constituents of the leaves, which also showed an interesting profile of tocopherols, organic acids, unsaturated fatty acids, and phenolic compounds. The infused extract of the commercial leaf sample was more effective than other preparations against lipid peroxidation and oxidative haemolysis. In turn, higher antibacterial activity was achieved with hydroethanolic and infused extracts of the wild sample, which extracts also displayed superior antifungal activity. Overall, the commercially acquired M. oleifera leaves stand out with better quality profiles than the wild collected, which aroused interest in studying the processing methods used locally to process this functional food.The authors are thankful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES to CIMO (UIDB/00690/2020) and to the Centre for Ecology, Evolution and Environmental Changes (cE3c) (UIDB/00329/2020). National funding by FCT, P.I., through the institutional scientific employment program-contract for the contracts of A. Fernandes and L. Barros, and through the individual scientific employment programcontract for the contract of J. Pinela (CEECIND/01011/2018). To the grants of A. Liberal (through the INTERNOVAMARKET-FOOD project) and A. Bancessi (SFRH/BD/135356/2017). This work was funded by FEDER-Interreg España-Portugal programme through the projects 0377_Iberphenol_6_E and TRANSCoLAB 0612_TRANS_CO_LAB_2_P, and also by the Ministry of Education, Science and Technological Development of Republic of Serbia (451-03-68/2020-14/200007).info:eu-repo/semantics/publishedVersio

Nutritional and phytochemical profiles and biological activities of Moringa oleifera Lam. edible parts from Guinea-Bissau (West Africa)

Moringa oleifera is an edible medicinal plant used to fight malnutrition in Africa. In this study, M. oleifera flowers, fruits and seeds from Guinea-Bissau were characterized for their nutritional composition and hydroethanolic and aqueous extracts were prepared to investigate the phenolic profiles and bioactivities. Seeds presented higher levels of proteins (~31 g/100 g dw), fat (~26 g/100 g dw) and flavan-3-ol derivatives, while carbohydrates, proteins, citric acid, and glycosylated flavonoids were abundant in fruits and flowers, these last samples also being rich in α-tocopherol (~18 mg/100 g dw). Some of the identified polyphenols had never been described in M. oleifera. In general, hydroethanolic extracts contained more polyphenols and were more active against lipid peroxidation, NO production, and tumour cells growth. Significant antimicrobial effects against the tested bacteria and fungi strains were displayed by both hydroethanolic and aqueous extracts. The M. oleifera potential to fight malnutrition and health issues was highlighted.info:eu-repo/semantics/publishedVersio

A water treatment strategy using Moringa oleifera (Lam) to prevent waterborne diseases in Guinea-Bissau

Waterborne infections remain a public health concern mainly in developing countries. Despite control initiatives undertaken by local and international authorities, namely the introduction of water, sanitation, and hygiene (WASH) policies and practices, in 2019, 702.974 cases of diarrhoea were reported in Biombo, an administrative region in northern (Guinea-Bissau). Therefore, promoting the adherence of the community to preventive practices has become an even major priority in order to reduce the rate of diarrhoeal diseases in the country. Due to the absence of a piped water distribution system, in most of the territory, and the community’s resistance to the most promoted household water treatment strategies such as chlorine and boiling, moringa has emerged as a promising strategy. This naturalized plant, easily found in all country have been showing water purifying effects in the recent literature. The present work started in 2018, by understanding what is known in general regarding moringa concerning its antimicrobial activity and its potential for water purification. For this purpose, an extensive literature review was conducted to clearly identify which parts of the plant are used, as well as the most effective extraction methods and concentrations for a greater number of pathogens. This review allowed us to clearly identify the part of the plant used, as well as the methods and the most effective concentration for a higher number of pathogens for antibacterial activity. The second step was to try to understand which are the hotspot areas for certain kinds of diseases such as (diarrhoeal diseases) in Guinea-Bissau, and which are the most contaminated water sources and which pathogens are present in these waters. For this purpose, we collected water samples in both dry and wet seasons and analyzed the physical-chemical and microbiological parameters of the three types of drinking water sources (Piped water, tubewell water2, and shallow well water3) in Bissau (urban) and its surroundings (peri-urban) and Quinhamel (rural). Simultaneously we collected samples of the moringa plant in four localities in Guinea-Bissau, made extracts in distilled water and ethanol, and tested their efficiency in Petri dishes in contaminated water in the laboratory, selecting the two pathogens responsible for gastrointestinal diseases most commonly found in water. Finally, we carried out social studies aimed at understanding the local community's perception of moringa before and after they tried it as a viable alternative for domestic water treatment, as well as its private and public management implications. In this context, qualitative focus group discussion and quantitative survey studies were carried out in a selected community. The results of the systematic review showed that there is no single effective method for all pathogens and that the concentrations used vary. Regarding the extract for antibacterial activity, the leaf is the part used, while the seed powder is used as a coagulant in the water treatment process. However, extraction with ethanol and distilled water showed to be the most effective for the highest number of pathogens at the concentration of 30 mg mL-1. Regarding the analysis of the three types of drinking water sources in Guinea-Bissau, the results show that all water sources present strong faecal contamination with greater emphasis on shallow wells, followed by tubewells and finally water supply system. In water supply systems, contamination tends to increase from the hole to the final consumer. In general, contamination tends to increase during the wet season for all three types of water sources. Moringa extracts are shown to have antibacterial activity and inhibit microbial growth. Of the two methods of extraction used (ethanol and distilled water), ethanol shown to be more effective than distilled water. These results are in agreement with those found in the literature, thus reinforcing that ethanol extracts are the most effective. For the social studies, results from both qualitative and quantitative analyses were consistent in identifying community perceptions that hinder adherence to household water treatment practices. The community, in general, showed great openness to the use of moringa and even buying it, and in general consider moringa much better than other methods. Overall, the main community perceptions observed as hindering the adherence to water treatment practices at the household level are: chlorine’s smell, change in taste of the water after the use of chlorine, difficulties in reaching chlorine or firewood to boil the water, time and financial issues among others. On the other hand, moringa is seen as a natural and odourless product, easily accessible and with nutritional and medicinal capacities. However, its availability throughout the year, conservation, and the moringa seed powder/water ratio are some of the difficulties presented. This work probably constitutes the most comprehensive study to date on the use of moringa as an alternative for domestic water treatment. It is thus hoped that the findings of this study can enhance the effectiveness of prevention and reduction of waterborne infectious diseases in endemic and epidemic regions at national and sub-regional levels

Efeito da digestão anaeróbia e da estabilizção com cal na mineralização do carbono e do azoto de lamas de ETAR Effect of anaerobic digestionand lime stabilization on sewage sludge carbon and nitrogen mineralization

Neste trabalho avaliou-se a mineralização do carbono e do azoto presente em diferentes tipos de lamas de ETAR: lama mista obtida por mistura de lamas primárias e secundárias (LM); lama mista tratada por digestão anaeróbia (LD) e lama digerida anaerobicamente tratada com cal (LDcal). Efectuaram-se incubações laboratoriais, em condições controladas, de misturas de lamas com um Arenossolo Háplico, durante 140 dias, tendo-se quantificado as emissões de CO2 e a evolução do azoto mineral nas misturas. A aplicação de LM originou uma imobilização inicial de N no solo e uma elevada emissão de CO2 (46% do C veiculado foi mineralizado) indicando que a MO presente nestas lamas está pouco estabilizada. Nas LD ocorreu mineralização líquida de N mas apenas 17% do C aplicado foi mineralizado, indicando a presença de matéria orgânica estabilizada. Pelo contrário, o tratamento com cal reduziu o azoto amoniacal das lamas mas estimulou a mineralização do carbono (40%) e do azoto orgânico (39,2%). As LD foram as que originaram, simultaneamente, a maior disponibilidade de N e a maior acumulação de C no solo.This work aims to evaluate the N and C mineralization in a Haplic Arenosol amended with 3 different sewage sludge: mixture of primary and secondary sewage sludge (MSS), anaerobically digested sewage sludge (DSS) and anaerobically digested sewage sludge treated with quicklime (LimeDSS). Two aerobic incubations, one to follow N mineralization and the other one to assess CO2 emissions, were performed during 140 days. MSS promoted soil N immobilization during the first days of incubation and higher CO2 emissions (46% of the applied C was lost), consequence of a high content of non-stabilized organic matter. In DSS there was nitrogen net mineralization but only 17% of the applied carbon was mineralized, showing that anaerobic digestion stabilized the sludge organic matter. Sewage sludge treatment with quicklime reduced its NH4+ content, but enhanced carbon (40%) and nitrogen (39.2%) mineralization after soil application. Anaerobic digested sewage sludge (DSS) seems to be the most interesting treatment, since it ensured a high level of available N to plants and a great contribution to C sequestration in soil