MCDA-DEA approach to construct a composite indicator for effluents from WWTPs considering the influence of PPCPs.

Considering current water situation, reuse is an effective solution to meet water demand and reduce pressure on conventional water sources. However, pharmaceutical and personal care products (PPCPs) in effluents from wastewater treatment plants (WWTPs) decrease their quality and suitability. With the aim of identifying and monitoring both the influence of PPCPs and the suitability of effluents to be reused, this study proposes the development of a composite indicator (CI) related to PPCP presence in WWTPs, through the common weight multi-criteria decision analysis (MCDA)-data envelopment analysis (DEA) model. Obtaining a CI for PPCPs is a novel approach in the published literature, showing a new perspective in PPCP management and their influence in wastewater treatment. Furthermore, this study proposes an improvement on MCDA-DEA model which maintains the initial hierarchy obtained for the units analyzed. The development of CI is based on information about the technological, environmental, social, and biological issues of WWTPs. Results show that 4 of the 33 WWTPs analysed had the best CI values, meaning that their effluents have lower environmental impact. The development of a CI related to PPCPs in WWTPs suggests that further steps are needed to manage the WWTP effluents. Hence, the need to implement preventive measures in WWTPs has been shown, even though the removal of PPCPs is not yet part of European law. This work highlights the importance of considering PPCPs as priority pollutants in wastewater management and reuse frameworks, to guarantee low environmental impact and adapt wastewater reuse based on a circular economy approach. HIGHLIGHTS: Emerging contaminants (PPCPs) are used as effluent quality indicators. A composite indicator for PPCPs performance has been developed through MCDA-DEA model. Indicator obtained allow decision makers implementing concrete actions to assess effluent quality. Results show the improvement capacity of the effluents quality through PPCPs removing.

The benefits of circular economy strategies in urban water facilities.

Circular economy has become a very popular item in the last decades in many fields. Particularly, in the water and wastewater sector, since a lot of pressure has been put on water resources. Although the main target of the application of circular economy in this sector has been waste management, the current research intends to extend its application to other aspects. In this sense, it is highlighted the role that asset management could play in wastewater treatments plants extending the useful life of the equipment and the facilities, and how it could contribute to the circular economy, measuring the impact in economic and environmental terms. Making use of the Analytical Hierarchy Process (AHP) it can be observed that maintenance tasks are one of the most important factors to avoid equipment deterioration. This research offers valuable results that will be useful to assess the condition of the equipment helping the decision-makers to optimize the maintenance tasks and plan replacement strategies that will lead to accomplishing the principles of circular economy, increasing the service life span of the equipment, and reducing the repairing costs, and minimizing the environmental impact associated to the replacement of the equipment.

Circular economy and payment for ecosystem services: A framework proposal based on water reuse.

Water scarcity forces the use of non-conventional water sources, to satisfy water demand, such as the effluent of wastewater treatment plants (WWTPs). Water reuse helps to close the urban water cycle and reduce pressure on available water resources, providing a bases for circular economy in the water sector. Under an ecosystem services (ES) point of view, if water reuse is considered the best management option in water scarcity areas, WWTPs are responsible for the ES of provisioning. One of the main requirements for the ES of provisioning is to guarantee the reclaimed water quality due to this water being discharged back into the ecosystem. Hence why removing pollutants, such as pharmaceutical and personal care products (PPCPs), is necessary to reduce the environmental impact of reused water. Considering the lack of legislation about PPCPs in effluents, this study proposes the use of the Payment for Ecosystem Services (PES) approach as an innovative solution to provide reclaimed water without PPCPs considering both the environmental and institutional context and the importance of WWTPs as non-conventional water sources. This study contributes to consider the PES as a water cycle management tool and its suitability to be used to remove PPCPs is highlighted, with the purpose of promoting water reuse in water scarcity areas under circular economy approach.

Identification and correction of congestion in wastewater treatment plants in the Community of Valencia, Spain.

The present work analyses the existence of congestion in a set of wastewater treatment plants (WWTPs) for the first time. The study sample included 47 WWTPs managed by the same operator and located in the Valencia region (eastern Spain). The method of analysis consisted in applying a new statistical model to identify and correct congestion situations based on data envelopment analysis (DEA), which takes into account undesirable outputs and multiple projections. The results showed a strong concentration of congested WWTPs (48.94-57.45%). Furthermore, the necessary corrections to avoid the congestion statuses entailed an average input reduction between 57.03 and 74.13% and an average increase in desirable outputs between 46.08% and 50.08%. In addition, only plant size had a significant relationship with the correction levels. The remaining contextual variables (age, overcapacity and type of water and sludge line) failed to show any significant impact on those corrections. To conclude, policy recommendations to improve the management of WWTPs are put forward, notably improving the management of smaller plants, which concentrate the largest percentage of correction.

Identification of effective parameters for anti-inflammatory concentration in València City's wastewater using fuzzy-set qualitative comparative analysis.

The current literature about pharmaceutical and personal care compounds (PPCPs) focuses on identifying their concentration and toxicological risk both in surface water and in wastewater. However, the influence of urban areas (population ageing, income level, hospitals and others) has not yet been analysed. Knowing how a population (and its facilities) affects PPCPs' presence in wastewater is important to identify the conditions that are responsible for their presence. In this work, the influence of water consumption, population ageing, income level, hospitals and nursing homes on the anti-inflammatory concentration have been analysed. To fill the gap between the quantitative data on PPCPs' concentration and the qualitative reasoning of the influence of urban areas on the anti-inflammatory concentration, the use of fuzzy-set qualitative comparative analysis (fsQCA) is proposed. The fsQCA results are presented as recipes that show the different causal combinations of conditions that explain the presence of anti-inflammatories in wastewater. Using fsQCA for urban wastewater management with the aim of explaining the presence of anti-inflammatories in wastewater treatment plants (WWTPs) is a novelty in the literature. The results obtained here show the influence of water consumption (WATCON), hospitals (HOSP) and population ageing (POPAG) as the main conditions for the anti-inflammatory concentration in Valèncian wastewater. Specifically, these conditions are present in all the recipes obtained with consistency of 99%. Through the results obtained, it would be possible to identify that HOSP are the main facilities that discharge anti-inflammatories into urban wastewater. Hence, the necessity of preventive measures to avoid the anti-inflammatory discharge into water bodies has been showed. Furthermore, under a methodological point of view, this work highlights the eligibility of fsQCA as a wastewater cycle management tool.

Efficiency of wastewater treatment facilities: The influence of scale economies.

The water cycle, from catchment to discharge, is a sector that involves an important investment and operation and maintenance costs. In particular, sewage treatment is a challenge for governments because they are having to consider economic, environmental, and social aspects. Within the European Union, implementation of Directive 91/271/EEC is responsible for the location of wastewater treatment facilities in the territory, due to the requirement that all urban areas must have this infrastructure to reduce the environmental impact of treated water in water bodies. Different sizes of municipalities affect the design of each wastewater treatment plant (WWTP) and cause variations in the operation process. The presence of scale economies in this sector has a significant influence on the efficiency of the wastewater treatment process and has a direct impact on the operational costs. Based on the pursuit of economic and environmental efficiency, this analysis extends the scope of the current literature because it recommends a specific, population equivalent (p.e.) range for which it would be suitable to achieve efficiency in wastewater treatment facilities-shedding light on the open debate about scale economies in WWTPs.

Machine learning for energy cost modelling in wastewater treatment plants.

Understanding the energy cost structure of wastewater treatment plants is a relevant topic for plant managers due to the high energy costs and significant saving potentials. Currently, energy cost models are generally generated using logarithmic, exponential or linear functions that could produce not accurate results when the relationship between variables is highly complex and non-linear. In order to overcome this issue, this paper proposes a new methodology based on machine-learning algorithms that perform better with complex datasets. In this paper, machine learning was used to generate high-performing energy cost models for wastewater treatment plants, using a database of 317 wastewater treatment plants located in north-west Europe. The most important variables in energy cost modelling were identified and for the first time, the energy price was used as model parameter and its importance evaluated.

The relevance of the design characteristics to the optimal operation of wastewater treatment plants: Energy cost assessment.

Operational parameters of the wastewater treatment process do not always fit the design ones for several reasons, such as the seasonality or an inaccurate estimation of the population connected. This fact has an effect on the performance of the Wastewater Treatment Plants (WWTPs) and their energy costs. The aim of this paper is to develop a cost function for the energy cost that takes into account the mismatching between the design and the operational inflow. For this purpose, a performance index is constructed in order to represent how far the operational inflow is from the design one, and will be included in the cost model. Moreover, three cost functions, depending on the size of the plants are developed in order to provide the managers of the WWTPs with valuable information that could be used to optimise the wastewater treatment process.

Monetary valuation of salicylic acid, methylparaben and THCOOH in a Mediterranean coastal wetland through the shadow prices methodology.

The presence of pharmaceutical and personal care products and drugs of abuse (PPCPs) in wastewater treatment plants (WWTPs) indicates discharge of the effluent may not be suitable for the ecological balance of water ecosystems, such as wetlands. These PPCPs degrade water quality, considered as an ecosystem service (ES), provoking serious environmental impacts. Assessing the monetary value of PPCPs can be used as a proxy for environmental status of the ES of water quality (ESWQ). Considering PPCPs as non-desirable outputs of WWTPs, the shadow prices methodology has been implemented using directional distance function to measure the environmental avoided cost of removing salicylic acid (SA), methylparaben (MP), and THCOOH from WWTPs effluents discharged to Albufera Natural Park (Spain). The SA shows the highest shadow price (138.16 €/µg), followed by THCOOH (48.15 €/µg), and MP (30.66 €/µg). These values are interpreted as the environmental cost that would be avoided if SA, MP, and THCOOH were removed from WWTPs effluents. The non-parametric tests show that wastewater treatment technology, together with population equivalent (as a proxy of the size of urban areas) and seasonality are factors that influence shadow prices obtained. The approach used in this study highlights the use of PPCPs as status indicators of ESWQ quantified in monetary units. As a way to synthesize the essential concepts to implement the shadow prices approach, this study proposes a flow diagram to represent the relationship between all the factors involved in this work. The use of shadow prices methodology proves that removing SA, MP, and THCOOH is associated with a measurable improvement in the ESWQ of Albufera Natural Park. The findings of this study will be useful for plant managers in order to make decisions about the removal of PPCPs in WWTPs effluents.

Modelling the energy costs of the wastewater treatment process: The influence of the aging factor.

Wastewater treatment plants (WWTPs) are aging and its effects on the process are more evident as time goes by. Due to the deterioration of the facilities, the efficiency of the treatment process decreases gradually. Within this framework, this paper proves the increase in the energy consumption of the WWTPs with time, and finds differences among facilities size. Accordingly, the paper aims to develop a dynamic energy cost function capable of predicting the energy cost of the process in the future. The time variable is used to introduce the aging effects on the energy cost estimation in order to increase the accuracy of the estimation. For this purpose, the evolution of energy costs will be assessed and modelled for a group of WWTPs using the methodology of cost functions. The results will be useful for the managers of the facilities in the decision making process.

Fermented milk containing Lactobacillus paracasei subsp. paracasei CNCM I-1518 reduces bacterial translocation in rats treated with carbon tetrachloride.

Probiotics can prevent pathological bacterial translocation by modulating intestinal microbiota and improving the gut barrier. The aim was to evaluate the effect of a fermented milk containing Lactobacillus paracasei subsp. paracasei CNCM I-1518 on bacterial translocation in rats with carbon tetrachloride (CCl4)-induced cirrhosis. Sprague-Dawley rats treated with CCl4 were randomized into a probiotic group that received fermented milk containing Lactobacillus paracasei subsp. paracasei CNCM I-1518 in drinking water or a water group that received water only. Laparotomy was performed one week after ascites development. We evaluated bacterial translocation, intestinal microbiota, the intestinal barrier and cytokines in mesenteric lymph nodes and serum. Bacterial translocation decreased and gut dysbiosis improved in the probiotic group compared to the water group. The ileal ß-defensin-1 concentration was higher and ileal malondialdehyde levels were lower in the probiotic group than in water group. There were no differences between groups in serum cytokines but TNF-α levels in mesenteric lymph nodes were lower in the probiotic group than in the water group. Fermented milk containing Lactobacillus paracasei subsp. paracasei CNCM I-1518 decreases bacterial translocation, gut dysbiosis and ileal oxidative damage and increases ileal ß-defensin-1 expression in rats treated with CCl4, suggesting an improvement in the intestinal barrier integrity.

Comparing the dynamic performance of wastewater treatment systems: A metafrontier Malmquist productivity index approach.

The assessment of productivity change of wastewater treatment plants (WWTPs) is essential to improve the performance over time of the facilities evaluated. This study assessed and compared the productivity growth of WWTPs operating with non-homogeneous technologies. The metafrontier Malmquist productivity index (MMPI) was computed for a sample of 99 WWTPs encompassing 4 alternative technologies: activated sludge (AS), aerated lagoon (AL), trickling filter (TF) and rotating biological contactor (BD). The results indicated that, on average, WWTPs with AS and BD exhibited better performance over time than WWTPs with AL and TF. The MMPI indicates that, over the period 2007-2009, the productivity rose by 0.9% and 0.3% for AS and BD technologies, respectively, whilst for the AL and TF processes, the productivity decreased by 0.5% and 2.2%, respectively. The decomposition of the MMPI into efficiency change (EC) and technical change (TC) illustrated that EC was a positive driver of productivity change for WWTPs that use AS, whilst TC contributed positively to the productivity growth of WWTPs using AL and BD. Several policy implications to help managers make informed decisions were drawn from our empirical analysis.

Assessment of wastewater treatment alternatives for small communities: An analytic network process approach.

The selection of the most appropriate wastewater treatment (WWT) technology is a complex problem since many alternatives are available and many criteria are involved in the decision-making process. To deal with this challenge, the analytic network process (ANP) is applied for the first time to rank a set of seven WWT technology set-ups for secondary treatment in small communities. A major advantage of ANP is that it incorporates interdependent relationships between elements. Results illustrated that extensive technologies, constructed wetlands and pond systems are the most preferred alternatives by WWT experts. The sensitivity analysis performed verified that the ranking of WWT alternatives is very stable since constructed wetlands are almost always placed in the first position. This paper showed that ANP analysis is suitable to deal with complex decision-making problems, such as the selection of the most appropriate WWT system contributing to better understand the multiple interdependences among elements involved in the assessment.

VSL#3 probiotic treatment decreases bacterial translocation in rats with carbon tetrachloride-induced cirrhosis.

BACKGROUND & AIMS: Probiotics can prevent pathological bacterial translocation in cirrhosis by modulating intestinal microbiota and improving gut barrier and immune disturbances. To evaluate the effect of probiotic VSL#3 on bacterial translocation, intestinal microbiota, gut barrier and inflammatory response in rats with experimental cirrhosis. METHODS: Forty-six Sprague-Dawley rats with CCl4 -induced cirrhosis were randomized into two groups: VSL#3 group (n = 22) that received VSL#3 in drinking water, and water group (n = 24) that received water only. Treatment began at week 6 of cirrhosis induction and continued until laparotomy, performed 1 week after development of ascites or at week 20. A control group included 11 healthy rats. At this study end, we evaluated bacterial translocation, intestinal flora, intestinal barrier (ileal claudin-2 and 4, ß-defensin-1, occludin and malondialdehyde as index of oxidative damage) and serum cytokines. RESULTS: Mortality during this study was similar in the VSL#3 group (10/22, 45%) and the water group (10/24, 42%) (P = 1). The incidence of bacterial translocation was 1/12 (8%) in the VSL#3 group, 7/14 (50%) in the water group (P = 0.03 vs. VSL#3 group) and 0/11 in the control group (P = 0.008 vs. water group). The concentration of ileal and caecal enterobacteria and enterococci was similar in the two groups of cirrhotic rats. The ileal occludin concentration was higher and ileal malondialdehyde and serum levels of TNF-α were lower in the VSL#3 group than in the water group (P < 0.05). CONCLUSIONS: VSL#3 decreases bacterial translocation, the pro-inflammatory state and ileal oxidative damage and increases ileal occludin expression in rats with experimental cirrhosis.

Economic feasibility study for improving drinking water quality: a case study of arsenic contamination in rural Argentina.

Economic studies are essential in evaluating the potential external investment support and/or internal tariffs available to improve drinking water quality. Cost-benefit analysis (CBA) is a useful tool to assess the economic feasibility of such interventions, i.e. to take some form of action to improve the drinking water quality. CBA should involve the market and non-market effects associated with the intervention. An economic framework was proposed in this study, which estimated the health avoided costs and the environmental benefits for the net present value of reducing the pollutant concentrations in drinking water. We conducted an empirical application to assess the economic feasibility of removing arsenic from water in a rural area of Argentina. Four small-scale methods were evaluated in our study. The results indicated that the inclusion of non-market benefits was integral to supporting investment projects. In addition, the application of the proposed framework will provide water authorities with more complete information for the decision-making process.

Predicting the pathological features of the mesorectum before the laparoscopic approach to rectal cancer.

Pelvic anatomy and tumour features play a role in the difficulty of the laparoscopic approach to total mesorectal excision in rectal cancer. The aim of the study was to analyse whether these characteristics also influence the quality of the surgical specimen. We performed a prospective study in consecutive patients with rectal cancer located less than 12 cm from the anal verge who underwent laparoscopic surgery between January 2010 and July 2013. Exclusion criteria were T1 and T4 tumours, abdominoperineal resections, obstructive and perforated tumours, or any major contraindication for laparoscopic surgery. Dependent variables were the circumferential resection margin (CMR) and the quality of the mesorectum. Sixty-four patients underwent laparoscopic sphincter-preserving total mesorectal excision. Resection was complete in 79.1% of specimens and CMR was positive in 9.7%. Univariate analysis showed tumour depth (T status) (P = 0.04) and promontorium-subsacrum angle (P = 0.02) independently predicted CRM (circumferential resection margin) positivity. Tumour depth (P < 0.05) and promontorium-subsacrum axis (P < 0.05) independently predicted mesorectum quality. Multivariate analysis identified the promontorium-subsacrum angle (P = 0.012) as the only independent predictor of CRM. Bony pelvis dimensions influenced the quality of the specimen obtained by laparoscopy. These measurements may be useful to predict which patients will benefit most from laparoscopic surgery and also to select patients in accordance with the learning curve of trainee surgeons.

Microbiome composition by pyrosequencing in mesenteric lymph nodes of rats with CCl4-induced cirrhosis.

BACKGROUND: The cross talk between the gut microbiota and the immune system, which is essential to maintain homeostasis, takes place at the intestinal lymphoid tissue such as the mesenteric lymph nodes (MLNs). Here, we investigated the presence of bacterial DNA in MLNs of control and cirrhotic rats and its relationship with inflammatory responses. METHODS: The MLN microbiome of cirrhotic rats with ascites, which was induced by carbon tetrachloride (CCl4), was compared to that of control rats using quantitative real-time PCR and pyrosequencing of the 16S rRNA gene. Cytokines in blood samples were assessed by ELISA. RESULTS: Unexpectedly, sequence analysis revealed a high microbial diversity in the MLNs of both control and cirrhotic rats with Proteobacteria as one of the most dominant phylum. CCl4-induced liver injury was not associated with a change in bacterial load, but it was linked to a decrease in microbial diversity (p < 0.05) and alterations in the microbial community in MLNs. A high proportion of Bifidobacterium animalis was also positively correlated with elevated interleukin-10 expression (p = 0.002, false discovery rate = 0.03, r = 0.94). CONCLUSIONS: For the first time, the high microbial diversity observed in MLNs of both controls and CCl4-induced cirrhotic rats provides evidence that bacterial translocation is more than a mere dichotomic phenomenon.

Modulation of inflammatory response in a cirrhotic rat model with induced bacterial peritonitis.

Bacterial peritonitis is a severe complication in patients with cirrhosis and ascites and despite antibiotic treatment, the inflammatory response to infection may induce renal dysfunction leading to death. This investigation evaluated the effect of TNF-α blockade on the inflammatory response and mortality in cirrhotic rats with induced bacterial peritonitis treated or not with antibiotics. Sprague-Dawley rats with carbon-tetrachloride-induced cirrhosis were treated with an intraperitoneal injection of 10(9) CFU of Escherichia coli diluted in 20 mL of sterile water to induce bacterial peritonitis and randomized to receive subcutaneously-administered placebo, ceftriaxone, anti-TNF-α mAb and ceftriaxone, or anti-TNF-α mAb alone. No differences were observed between groups at baseline in respect to renal function, liver hepatic tests, serum levels of nitrite/nitrate and TNF-α. Treatment with ceftriaxone reduced mortality (73.3%) but differences did not reach statistical significance as compared to placebo. Mortality in rats treated with ceftriaxone and anti-TNF-α mAb was significantly lower than in animals receiving placebo (53% vs. 100%, p<0.01). Serum TNF-α decreased significantly in surviving rats treated with ceftriaxone plus anti-TNF-α mAb but not in treated with antibiotics alone. Additional studies including more animals are required to assess if the association of antibiotic therapy and TNF-α blockade might be a possible approach to reduce mortality in cirrhotic patients with bacterial peritonitis.

Economic feasibility study for new technological alternatives in wastewater treatment processes: a review.

The concept of sustainability involves the integration of economic, environmental, and social aspects and this also applies in the field of wastewater treatment. Economic feasibility studies are a key tool for selecting the most appropriate option from a set of technological proposals. Moreover, these studies are needed to assess the viability of transferring new technologies from pilot-scale to full-scale. In traditional economic feasibility studies, the benefits that have no market price, such as environmental benefits, are not considered and are therefore underestimated. To overcome this limitation, we propose a new methodology to assess the economic viability of wastewater treatment technologies that considers internal and external impacts. The estimation of the costs is based on the use of cost functions. To quantify the environmental benefits from wastewater treatment, the distance function methodology is proposed to estimate the shadow price of each pollutant removed in the wastewater treatment. The application of this methodological approach by decision makers enables the calculation of the true costs and benefits associated with each alternative technology. The proposed methodology is presented as a useful tool to support decision making.