Impact of treatment plant management on human health and ecological risks from wastewater irrigation in developing countries - case studies from Cochabamba, Bolivia.

Wastewater irrigation is a common practice in developing countries due to water scarcity and increasing demand for food production. However, there are health risks and ecological risks associated with this practice. Small-scale wastewater treatment plants (WWTPs) intend to decrease these risks but still face management challenges. This study assessed how the management status of five small-scale WWTPs in Cochabamba, Bolivia affects health risks associated with consumption of lettuce and ecological risks due to the accumulation of nutrients in the soil for lettuce and maize crops. Risk simulations for three wastewater irrigation scenarios were: raw wastewater, actual effluent and expected effluent. Results showed that weak O&M practices can increase risk outcomes to higher levels than irrigating with raw wastewater. Improving O&M to achieve optimal functioning of small-scale WWTPs can reduce human health risks and ecological risks up to 2 log10 DALY person-1 year-1 and to 2 log10 kg nitrogen ha-1 accumulated in soil, respectively.

Computational and statistical modeling for parameters optimization of electrochemical decontamination of synozol red dye wastewater.

In this study, computational and statistical models were applied to optimize the inherent parameters of an electrochemical decontamination of synozol red. The effect of various experimental variables such as current density, initial pH and concentration of electrolyte on degradation were assessed at Ti/RuO0·3TiO0·7O2 anode. Response surface methodology (RSM) based central composite design was applied to investigate interdependency of studied variables and train an artificial neural network (ANN) to envisage the experimental training data. The presence of fifteen neurons proved to have optimum performance based on maximum R2, mean absolute error, absolute average deviation and minimum mean square error. In comparison to RSM and empirical kinetics models, better prediction and interpretation of the experimental results were observed by ANN model. The sensitive analysis revealed the comparative significance of experimental variables are pH = 61.03%>current density = 17.29%>molar concentration of NaCl = 12.7%>time = 8.98%. The optimized process parameters obtained from genetic algorithm showed 98.6% discolorization of dye at pH 2.95, current density = 5.95 mA cm-2, NaCl of 0.075 M in 29.83 min of electrolysis. The obtained results revealed that the use of statistical and computational modeling is an adequate approach to optimize the process variables of electrochemical treatment.

A call-to-action for sustainability in dialysis in Brazil / Um apelo pela sustentabilidade na diálise no Brasil

ABSTRACT Human-induced climate change has been an increasing concern in recent years. Nephrology, especially in the dialysis setting, has significant negative environmental impact worldwide, as it uses large amounts of water and energy and generates thousands of tons of waste. While our activities make us responsible agents, there are also several opportunities to change the game, both individually and as a society. This call-to-action intends to raise awareness about environmentally sustainable practices in dialysis and encourages this important discussion in Brazil.

RESUMO A mudança climática induzida pela atividade humana tem sido foco de preocupações crescentes nos últimos anos. A nefrologia, particularmente a diálise, produz significativos impactos ambientais em todo o mundo em virtude da grande utilização de água e energia e da geração de milhares de toneladas de resíduos. Embora nossas atividades nos tornem agentes responsáveis, há várias oportunidades para mudar esse cenário, tanto individualmente como em sociedade. O presente artigo pretende ampliar a conscientização sobre práticas ambientalmente sustentáveis em diálise e estimular essa importante discussão no Brasil.

A call-to-action for sustainability in dialysis in Brazil.

Human-induced climate change has been an increasing concern in recent years. Nephrology, especially in the dialysis setting, has significant negative environmental impact worldwide, as it uses large amounts of water and energy and generates thousands of tons of waste. While our activities make us responsible agents, there are also several opportunities to change the game, both individually and as a society. This call-to-action intends to raise awareness about environmentally sustainable practices in dialysis and encourages this important discussion in Brazil.

Exploring the influence of meteorological conditions on the performance of a waste stabilization pond at high altitude with structural equation modeling.

Algal photosynthesis plays a key role in the removal mechanisms of waste stabilization ponds (WSPs), which is indicated in the variations of three parameters, dissolved oxygen, pH, and chlorophyll a. These variations can be considerably affected by extreme climatic conditions at high altitude. To investigate these effects, three sampling campaigns were conducted in a high-altitude WSP in Cuenca (Ecuador). From the collected data, the first application of structure equation modeling (SEM) on a pond system was fitted to analyze the influence of high-altitude characteristics on pond performance, especially on the three indicators. Noticeably, air temperature appeared as the highest influencing factors as low temperature at high altitude can greatly decrease the growth rate of microorganisms. Strong wind and large diurnal variations of temperature, 7-20 °C, enhanced flow efficiency by improving mixing inside the ponds. Intense solar radiation brought both advantages and disadvantages as it boosted oxygen level during the day but promoted algal overgrowth causing oxygen depletion during the night. From these findings, the authors proposed insightful recommendations for future design, monitoring, and operation of high-altitude WSPs. Moreover, we also recommended SEM to pond engineers as an effective tool for better simulation of such complex systems like WSPs.

Modeling and dynamic simulation of a two-stage pre-denitrification MBBR system under increasing organic loading rates.

Biofilm-based wastewater treatment systems have become attractive due to their numerous advantages when compared to other suspended growth processes. However, the mathematical modeling of these reactors is relatively complex, since it has to consider a wide range of phenomena to accurately describe the process behavior. This work deals with the modeling of a two-stage MBBR system run in pre-denitrification mode for the removal of organic matter and nitrogen from wastewater. The model development took into account diffusive phenomena and kinetics in a homogeneous biofilm composed of different bacterial functional groups (namely heterotrophs and nitrifiers). The thickness of the biofilm was treated as a variable, given that detachment of adhered biomass took place. The suspended biomass fraction was also considered to remove the pollutants by means of Monod-type kinetics associated with the activated sludge model. The dynamic behavior of the components involved in the system and their spatial distribution in the biofilm obtained from simulated data showed good agreement with those reported in the literature, demonstrating the reproducibility of the model and encouraging future applications in full-scale MBBR plants.

The influence of solid-liquid coefficient in the fate of pharmaceuticals and personal care products in aerobic wastewater treatment.

Wastewater treatment plants (WWTPs) are considered to be a source of environmental contamination by micropollutants, especially from pharmaceuticals and personal care products (PCPs). The pathway of those compounds during sewage treatment has been investigated, but data from real-scale WWTPs is still missing (for example, the values of the solid-liquid coefficient (Kd) during treatment). This paper uses the Kd values for some pharmaceuticals and PCPs (fenofibrate, gemfibrozil, propranolol, metoprolol, salicylic acid, acetylsalicylic acid, ibuprofen, diclofenac, naproxen, fenoprofen, caffeine, triclosan, methylparaben, ethylparaben, propylparaben, butylparaben, and benzylparaben) to describe the micropollutants' behavior in the treatment process. In order to attain this data, an aerobic wastewater treatment plant located in Brazil was studied. Six samplings were carried out and a mass balance was performed, associating the concentrations of the micropollutants in the liquid phase with the solid phase (sludge and suspended solids). Of all the compounds analyzed, caffeine was the most biodegradable pollutant, as almost 98% of its mass was biodegraded. In contrast, triclosan had the highest load in sludge (median of 163.0 mg day-1) and adsorbed in SS (median of 0.593 mg day-1) at the output. Summing up, each micropollutant had a specific way to be removed during wastewater treatment.

Residual volume in vials of antibiotics used in pediatrics.

OBJECTIVE: Quantifying residual volume contained in vials of antibiotics used in pediatrics. METHOD: This is an experiment involving samples from vials of antibiotics used in a pediatric hospital. Residual volume was identified by calculating the difference in weight measurement before and after the vials were washed. Evaluation of the residual volume difference in the vials was determined by the Wilcoxon non-parametric test for a sample and established at a significance level of 5%. RESULTS: 105 samples of antibiotics were selected. The correct use of the antibiotics oxacillin (88.57%) and ceftriaxone (94.28%) predominated with low residual values. The same did not occur for procaine benzylpenicillin + potassium benzylpenicillin, since a greater residual volume was discarded in 74.28% of the vials. CONCLUSION: We highlight the need for improvements in managing antibiotics in the institution under study, so that the excess volume of the antibiotics in the vials is used within the acceptable stable time. It is also necessary that the disposal of the residual volume be adequately disposed, since it presents a risk to public health and the environment. OBJETIVO: Quantificar o volume residual contido em frascos-ampola de antibióticos utilizados na pediatria. MÉTODO: Trata-se de um experimento com amostras de frascos-ampola de antibióticos utilizados em hospital pediátrico. O volume residual foi identificado calculando-se a diferença da aferição do peso antes e após a lavagem do frasco-ampola. A avaliação da diferença dos volumes residuais nos frascos-ampola foi determinada pelo teste não paramétrico de Wilcoxon para uma amostra e estabelecido o nível de significância de 5%. RESULTADOS: Foram selecionadas 105 amostras de antibióticos. Predominou o correto aproveitamento dos antibióticos oxacilina (88,57%) e ceftriaxona (94,28%), com baixos valores residuais. O mesmo não ocorreu com a benzilpenicilina procaína + potássica, pois em 74,28% dos frascos houve descarte de volume residual superior. CONCLUSÃO: Destaca-se a necessidade de melhorias na gestão dos antibióticos na instituição em estudo, para que o volume excedente do antibiótico em frasco-ampola seja aproveitado até o tempo de estabilidade permitido, assim como é necessário que haja a adequação da forma de descarte do volume residual, que apresenta risco à saúde pública e ao meio ambiente.

[Environmental conditions and prevalence of parasitic infection in Xukuru-Kariri indigenous people, Caldas, Brazil]. / Condições ambientais e prevalência de infecção parasitária em indígenas Xukuru-Kariri, Caldas, Brasil.

OBJECTIVE: To describe the environmental conditions and the parasitic infection status of Xukuru-Kariri individuals living in the municipality of Caldas, state of Minas Gerais, Brazil. METHODS: A cross-sectional study was carried out in March 2009. Sociodemographic and environmental data were collected through interviews. Water and fecal samples were collected for determination of environmental contamination and parasitic infection status. RESULTS: The Xukuru-Kariri population living in Caldas included 86 people divided into 22 families. Of 22 heads of household, 81.8% had low schooling (not higher than elementary education). Of 26 water samples collected for microbiological analysis, 77.0% were positive for total coliforms and 4.0% for Escherichia coli. Residents of 27.3% of households defecated in the open. Trash was scattered in the yard of 54.5% of households. Fecal samples were collected from 60 individuals, with parasitic infection in 66.6%. The following prevalence rates were recorded: Entamoeba histolytica/dispar, 6.7%; Entamoeba coli, 60.0%; Endolimax nana, 1.8%; and Giardia duodenalis, 6.6%. CONCLUSIONS: The people included in this study faced environmental characteristics that contributed to their health vulnerability. Health actions as well as the implementation of public policies to provide sanitation, with quality water and adequate collection and treatment of human and household waste, are essential to prevent environmental degradation and improve the quality of life of these individuals.

First evaluation of illicit and licit drug consumption based on wastewater analysis in Fort de France urban area (Martinique, Caribbean), a transit area for drug smuggling.

Drugs of abuse are increasingly consumed worldwide. Such consumption could be back-calculated based on wastewater content. The West Indies, with its coca production and its thriving illicit drug market, is both a hub of world cocaine trafficking and a place where its consumption is prevalent particularly in the form of crack. The present study will firstly investigate Caribbean consumption by a daily 5 to 7 day sampling campaign of composite wastewater samples from the four wastewater treatment plants of the Martinique capital, including working and non-working periods. The local consumption of cocaine is ten to thirty times higher than OECD standards because of the prevalence of crack. The excretion coefficient for crack consumption and the impact of temperature on drug stability need further investigation. However, the low diversity of illicit drugs consumed and the crack prevalence suggest practices driven by the transiting of drugs for international trafficking.

Occurrence and removal of estrogens in Brazilian wastewater treatment plants.

This paper evaluated the occurrence and removal efficiency of four estrogenic hormones in five biological wastewater treatment plants (WWTPs), located in the State of Ceará, Brazil. The five WWTPs comprised: two systems consisted of one facultative pond followed by two maturation ponds, one facultative pond, one activated sludge (AS) system followed by a chlorination step, and one upflow anaerobic sludge blanket (UASB) reactor followed by a chlorination step. Estrogen occurrence showed a wide variation among the analyzed influent and effluent samples. Estrone (E1) showed the highest occurrence in the influent (76%), whereas both 17ß-estradiol (E2) and 17α-ethynylestradiol (EE2) presented a 52% occurrence, and the compound 17ß-estradiol 17-acetate (E2-17A), a 32% one. The occurrence in the effluent samples was 48% for E1, 28% for E2, 12% for E2-17A, and 40% for EE2. The highest concentrations of E1 and EE2 hormones in the influent were 3050 and 3180 ng L(-1), respectively, whereas E2 and E2-17A had maximum concentrations of 776 and 2300 ng L(-1), respectively. The lowest efficiencies for the removal of estrogenic hormones were found in WWTP consisted of waste stabilization ponds, ranging from 54 to 79.9%. The high-rate systems (AS and UASB), which have chlorination as post-treatment, presented removal efficiencies of approximately 95%.

Methane production and hydrolysis kinetics in the anaerobic degradation of wastewater screenings.

Anaerobic biodegradability and hydrolysis rates of wastewater screenings were determined using the biochemical methane potential test at 37 °C. The extent and rate of screenings conversion to methane of this complex and particulate substrate were investigated and since two stages of hydrolysis were identified, corresponding to the different types of materials in screenings, a linear and non-linear model was used. No accumulation of intermediary products was observed and so it was possible to use the methane production rate and a linear model to estimate the hydrolysis rate in the first phase of hydrolysis. The measured values of 0.061-0.127 d(-1) are in the range reported for other comparable organic wastes. It was also observed that the inoculum-to-substrate ratio has a large impact on methane production rate of screenings. The difference in biodegradation rates from the materials in screenings and the overall hydrolysis could be represented by the modified Gompertz non-linear model which was able to describe the methane production rate of screenings with a high confidence. Screenings were found to have 52% biodegradability on average and this shows the potential for volatile solids destruction. A two-stage process with an improved hydrolysis rate is proposed to ensure that the full potential of the material is exploited.

Dissolved inorganic nutrients and chlorophyll A in an estuary receiving sewage treatment plant effluents: Cachoeira River estuary (NE Brazil).

Sampling was conducted monthly during a transition period between the dry and rainy seasons in order to evaluate the effectiveness of a municipal sewage treatment plant (STP) in eutrophication control. STP effluent and fluvial input data were also estimated. In the dry period, high concentrations of nutrients, chlorophyll a (up to 360 µg L(-1)), and anoxia in bottom waters were observed in the upper portion of the estuary. Nitrate was scarce during the dry months, although high concentrations were observed at the river sources and the upper estuary. The N:P and Si:P molar ratios were usually below 16:1, and the Si:N ratio was higher than 1:1. The fluvial inputs were a greater source of nutrients to the estuary than the STP, but nutrient loading by these effluents were also important in contributing to the eutrophication of the upper estuarine zone, especially in the dry season when symptoms were more intense.

Evaluation of the sensitivity of freshwater organisms used in toxicity tests of wastewater from explosives company.

Explosives industries are a source of toxic discharge. The aim of this study was to compare organisms sensitivity (Daphnia similis, Danio rerio, Escherichia coli and Pseudomonas putida) in detecting acute toxicity in wastewater from two explosives, 2,4,6-TNT (TNT) and nitrocellulose. The samples were collected from an explosives company in the Paraiba Valley, São Paulo, Brazil. The effluents from TNT and nitrocellulose production were very toxic for tested organisms. Statistical tests indicated that D. similis and D. rerio were the most sensitive organisms for toxicity detection in effluents from 2,4,6-TNT and nitrocellulose production. The P. putida bacteria was the organism considered the least sensitive in indicating toxicity in effluents from nitrocellulose.

Chemical components of bleached eucalypt kraft pulp effluent COD and treatment removal efficiency during normal mill operation and maintenance shutdowns.

In order to meet increasingly strict Brazilian COD emissions limits, mills must understand the components that contribute to effluent COD, how these vary between normal mill operation and maintenance shutdowns, and how this variation affects treatment efficiency. To this end, primary and secondary effluents from a Brazilian bleached eucalypt kraft pulp mill activated sludge system were analyzed for COD, lignin, extractives, carbohydrates and AOX over a sixth month period that included two general maintenance shutdowns and four months of normal operation. Primary effluent presented significantly different compositions during periods of normal operation and mill shutdowns. During normal operation, the main components of effluent COD (909 mg/l average) were carbohydrates, followed by lignin. However, the lignin fraction was the main component of secondary effluent COD during both normal operation and mill shutdowns. Higher removal efficiencies for COD carbohydrates and AOX were observed during normal operation compared to shutdowns, while no difference in removal efficiencies of lignin and extractives was observed. Carbohydrate removal efficiency was significantly lower in one of the parallel treatment lines. The different removal efficiencies reflect not only variations in effluent composition, but possibly differences in system operational control which should be explored in greater detail.

Disposal of human milk donated to a human milk bank before and after measures to reduce the amount of milk unsuitable for consumption.

OBJECTIVE: To evaluate the causes of disposal of donated human milk and the impact of the measures taken to reduce the amount of milk unsuitable for consumption. METHODS: A quasi-experimental, observational, comparative study was conducted with different populations of external donors in 2006 and 2008. In 2006, a simple form was used to record the criteria for disposal of the donated milk. We also interviewed the donors to find the reason of changes in the milk. In 2008, a checklist containing comprehensive guidance for milk collection and pre-storage was handed out to the donors. Next, we continued to survey the disposal criteria after the intervention using the same form administered in 2006. A case was defined as all bottles of milk of the same donor discarded per day. Data were analyzed by calculations based on comparison of proportions for 2006 and 2008. RESULTS: Twenty-four percent of the milk collected was discarded in 2006, while in 2008 only 10.5% of the milk was discarded. There was significant reduction in the disposal of milk for the items: cigarette odor; forgetting the milk outside the refrigerator, inside it or on its door; problems with the freezer; frequent opening of the refrigerator and freezer; expiration date; and unidentified cases. However, there was a significant increase in milk disposal for first milk collection without guidance; use of inappropriate bottle; milk transportation from work to home; and indirect guidance. CONCLUSIONS: The use of the step-by-step checklist had a positive impact on the reduction of the volume of donated milk discarded and changed the frequency of the causes of disposal, eliminating some of these causes.

Descarte de leite humano doado a Banco de Leite antes e após medidas para reduzir a quantidade de leite imprópria para consumo / Disposal of human milk donated to a human milk bank before and after measures to reduce the amount of milk unsuitable for consumption

OBJETIVO: Avaliar as causas do descarte do leite humano doado, bem como o impacto das medidas adotadas para diminuir a quantidade de leite impróprio. MÉTODOS: Realizou-se um estudo observacional comparativo do tipo quasi-experimental com populações distintas de doadoras externas nos anos de 2006 e 2008. Utilizou-se, em 2006, um formulário simples para registrar os critérios de descarte do leite doado e o diálogo com a doadora para encontrar o motivo das alterações do leite. Para as doadoras de 2008, aplicou-se um checklist de orientação detalhada da técnica de coleta e pré-estocagem. Seguiu-se o levantamento dos critérios de descarte após a intervenção por meio do mesmo formulário aplicado em 2006. Definiu-se como um "caso" todos os frascos de leite descartados por dia de uma mesma doadora. Os dados foram analisados pelos cálculos de comparação de proporções para os anos de 2006 e 2008. RESULTADOS: Vinte e quatro por cento do leite coletado foi descartado em 2006, enquanto que, em 2008, apenas 10,5 por cento do leite foi descartado. Houve redução significativa no descarte de leite para os itens: cheiro de cigarro; esquecimento do leite fora, no corpo ou na porta da geladeira; problemas com o freezer; abrir muito geladeira e freezer; prazo de validade vencida; e casos não identificados. Os itens primeira coleta sem orientação, uso de frasco não conforme, transporte do leite do trabalho para casa e orientação indireta apresentaram aumentos significativos de descarte. CONCLUSÕES: A aplicação do checklist passo a passo teve um impacto positivo na redução do volume de leite doado descartado e modificou as frequências das causas desse descarte, eliminando algumas dessas causas.

OBJECTIVE: To evaluate the causes of disposal of donated human milk and the impact of the measures taken to reduce the amount of milk unsuitable for consumption. METHODS: A quasi-experimental, observational, comparative study was conducted with different populations of external donors in 2006 and 2008. In 2006, a simple form was used to record the criteria for disposal of the donated milk. We also interviewed the donors to find the reason of changes in the milk. In 2008, a checklist containing comprehensive guidance for milk collection and pre-storage was handed out to the donors. Next, we continued to survey the disposal criteria after the intervention using the same form administered in 2006. A case was defined as all bottles of milk of the same donor discarded per day. Data were analyzed by calculations based on comparison of proportions for 2006 and 2008. RESULTS: Twenty-four percent of the milk collected was discarded in 2006, while in 2008 only 10.5 percent of the milk was discarded. There was significant reduction in the disposal of milk for the items: cigarette odor; forgetting the milk outside the refrigerator, inside it or on its door; problems with the freezer; frequent opening of the refrigerator and freezer; expiration date; and unidentified cases. However, there was a significant increase in milk disposal for first milk collection without guidance; use of inappropriate bottle; milk transportation from work to home; and indirect guidance. CONCLUSIONS: The use of the step-by-step checklist had a positive impact on the reduction of the volume of donated milk discarded and changed the frequency of the causes of disposal, eliminating some of these causes.