Acceptance of new sanitation: The role of end-users' pro-environmental personal norms and risk and benefit perceptions

Agriculture and environmental management through nanotechnology: Eco-friendly nanomaterial synthesis for soil-plant systems, food safety, and sustainability

Through the advancement of nanotechnology, agricultural and food systems are undergoing strategic enhancements, offering innovative solutions to complex problems. This scholarly essay thoroughly examines nanotechnological innovations and their implications within these critical industries. Traditional practices are undergoing radical transformation as nanomaterials emerge as novel agents in roles traditionally filled by fertilizers, pesticides, and biosensors. Micronutrient management and preservation techniques are further enhanced, indicating a shift towards more nutrient-dense and longevity-oriented food production. Nanoparticles (NPs), with their unique physicochemical properties, such as an extraordinary surface-to-volume ratio, find applications in healthcare, diagnostics, agriculture, and other fields. However, concerns about their potential overuse and bioaccumulation raise unanswered questions about their health effects. Molecule-to-molecule interactions and physicochemical dynamics create pathways through which nanoparticles cause toxicity. The combination of nanotechnology and environmental sustainability principles leads to the examination of green nanoparticle synthesis. The discourse extends to how nanomaterials penetrate biological systems, their applications, toxicological effects, and dissemination routes. Additionally, this examination delves into the ecological consequences of nanomaterial contamination in natural ecosystems. Employing robust risk assessment methodologies, including the risk allocation framework, is recommended to address potential dangers associated with nanotechnology integration. Establishing standardized, universally accepted guidelines for evaluating nanomaterial toxicity and protocols for nano-waste disposal is urged to ensure responsible stewardship of this transformative technology. In conclusion, the article summarizes global trends, persistent challenges, and emerging regulatory strategies shaping nanotechnology in agriculture and food science. Sustained, in-depth research is crucial to fully benefit from nanotechnology prospects for sustainable agriculture and food systems.

Determinants of household safe drinking water practices in Kabul, Afghanistan: New insights from behavioural survey data

More than 2 billion people worldwide lack access to safe drinking water. Household water treatment (HWT) is an interim option for reducing the risk of water born disease. Understanding the factors that influence HWT behaviour is crucial for delivering successful interventions aimed at scaling relevant technologies, but the literature tends to emphasise psychological determinants with little consideration of socioeconomic and contextual factors. This article responds to this literature by using the COM-B model to examine the determinants of HWT practices through a comprehensive and context-sensitive behaviour definition. We informed this model through a cross-sectional survey design in which we collected data from 913 households in two peri‑urban neighbourhoods of Kabul, Afghanistan. Our findings from descriptive statistical and regression analysis highlight the importance of not only psychological but also socio-economic and contextual determinants of HWT behaviour: Especially the COM-B dimensions of reflective and automatic motivation, and physical opportunity - which are heavily influenced by local context and economic circumstances - had statistically significant associations with performing HWT. The practical significance of these dimensions was similarly pronounced. For example, an increase in the physical opportunity index by 0.1 units from an average value of 0.7 to 0.8 would be associated with a 7.7 percentage-point higher likelihood of HWT performance. These results suggest that the COM-B model can be utilised to systematically design interventions aimed at promoting HWT practices, while highlighting the need to broaden behavioural analyses of HWT and consider contextual factors to develop interventions that are tailored to the specific needs and obstacles of different communities.

Anaerobic dynamic membrane bioreactors for synthetic blackwater treatment under room temperature and mesophilic conditions

Two anaerobic dynamic membrane bioreactors (AnDMBRs) were set up for the treatment of synthetic blackwater at room temperature (20-25 °C) and mesophilic conditions for 180 days with progressively increased organic loading rates(OLR). Despite dynamic membranes (DM), organics removal at room temperature was similar to removal within the mesophilic conditions of the reactor, with some disparities in methane production. A dense sludge filtration layer was more likely to be formed on the DM at room temperature, resulting in a faster membrane fouling. Microbial community analysis revealed that microorganisms had higher richness and lower diversity at room temperature, which was beneficial to the growth of Actinobacteriota, especially Propioniciclava. This comparative study discusses the feasibility of operating an AnDMBR under room temperature conditions versus mesophilic conditions. This analysis provides novel insights into future large-scale attempts to treat blackwater at room temperature.

Tannin-based coagulant for harvesting microalgae cultivated in wastewater: Efficiency, floc morphology and products characterization

Tannin-based coagulants (TBCs) have the potential to be used to harvest microalgae cultivated at wastewater treatment plants. Their use would address the circular economy associated with the production of low-toxicity biomass and supernatant. Studies in this field are still scarce, and substantial gaps exist in the definitions of the flocculation process parameters. In this context, the objective of this work was to evaluate TBC performance as a natural coagulant for harvesting microalgae biomass grown in sanitary effluent digested in an up flow biofilter, as well establishing a path to enable recovery and reuse of wastewater nutrients. Classical removal techniques combined with image analysis and light scattering-based equipment were used to evaluate the coagulant performance, recovery efficiency, floc strength, and floc recovery compared to aluminum sulfate (AS). The results showed that TBC was able to efficiently harvest algal biomass from the effluent, achieving color, turbidity, and optical density (OD) removal efficiencies greater than 90% with only 5 min of sedimentation. The optimal harvesting dosage was 100 mg·L^-1 for TBC and 75 mg·L^-1 for AS. TBC presented the advantage of harvesting biomass without changing the pH of the medium and was also able to present satisfactory removal of the analyzed parameters (color, turbidity and OD) at pH values of 5.0, 7.0, and 8.5. In addition, TBC produced stronger flocs than AS, showing a better ability to resist breakage upon sudden shear rate variations. TBC produced macronutrient-rich biomass and supernatant that was similar to that produced with AS.

The Perception of Water Contamination and Risky Consumption in El Salvador from a Community Clinical Psychology Perspective

This study was carried out as part of the international cooperation project “Agua Futura” for the improvement of water resource management and the promotion of water, sanitation, and hygiene (WASH) behaviors in rural communities of Central America. Given the relevant healthcare problem of water pollution, especially in El Salvador, the aim was to detect some key factors affecting the perception of water contamination and its risky consumption from a community clinical psychological perspective. Ninety rural inhabitants of El Salvador were administered a structured interview exploring their perceptions about water quality and the impact of water consumption on health. Data were analyzed through a computer-aided thematic analysis—complemented by a qualitative analysis—allowing the detection of sense-making processes based on lexical variability. Different themes were identified with regard to the perception of water quality (i.e., mistrust, danger, and safety) and the beliefs about the impact of water consumption on health (i.e., rationalization, denial, awareness, displacement, and isolation of affect). The results showed heterogeneous perspectives about water quality and sanitation. However, the perceived negative impact of water consumption on health was mostly denied or minimized through massive distortions. Overall, the study highlights the role of defensive patterns in facing issues of water contamination, which may prevent the community from adopting healthy behaviors and adequate water management behaviors.

Systematic review of the last 20 years of research on decentralized domestic wastewater treatment in Brazil: state of the art and potentials

A DEWATS (decentralized wastewater treatment system) is an alternative for expanding sanitation. In Brazil, DEWATS is acknowledged by law and is part of the National Sanitation Plan strategy for achieving the treatment of 85.6% of all the generated wastewater by 2033, improving the current treatment index of 49%. This review's aim is to identify DEWATS studies in Brazil and to verify their potential for narrowing the national wastewater treatment deficit. Hence, aspects such as cost, maintenance, and efficiency were assessed. The archival research method (ARM) was used to identify papers published in the last 20 years through the scientific databases of Scopus, Science Direct, and Web of Science. Data regarding the general characteristics of each study were collected and compared to Brazilian environmental regulation and sanitation status. The results showed the evaluation of different technologies such as DEWATS, highlighting their flexibility and potential use in 79% of Brazilian counties. However, although 81% of the studies conducted performance analysis, none covered the main parameters required by Brazilian law. Although legal gaps for DEWATS improvement and consolidation have been identified and the interest in studying DEWATS has been increasing in the last five years, many barriers to their widespread use remain.

An integrated assessment of environmental, economic, social and technological parameters of source separated and conventional sanitation concepts: A contribution to sustainability analysis

Resource recovery and reuse from domestic wastewater has become an important subject for the current development of sanitation technologies and infrastructures. Different technologies are available and combined into sanitation concepts, with different performances. This study provides a methodological approach to evaluate the sustainability of these sanitation concepts with focus on resource recovery and reuse. St. Eustatius, a small tropical island in the Caribbean, was used as a case study for the evaluation. Three source separation-community-on-site and two combined sewerage island-scale concepts were selected and compared in terms of environmental (net energy use, nutrient recovery/reuse, BOD/COD, pathogens, and GHG emission, land use), economic (CAPEX and OPEX), social cultural (acceptance, required competences and education), and technological (flexibility/adaptability, reliability/continuity of service) indicators. The best performing concept, is the application of Upflow Anaerobic Sludge Bed (UASB) and Trickling Filter (TF) at island level for combined domestic wastewater treatment with subsequent reuse in agriculture. Its overall average normalised score across the four categories (i.e., average of average per category) is about 15% (0.85) higher than the values of the remaining systems and with a score of 0.73 (conventional activated sludge - centralised level), 0.77 (UASB-septic tank (ST)), 0.76 (UASB-TF - community level), and 0.75 (ST - household level). The higher score of the UASB-TF at community level is mainly due to much better performance in the environmental and economic categories. In conclusion, the case study provides a methodological approach that can support urban planning and decision-making in selecting more sustainable sanitation concepts, allowing resource recovery and reuse in small island context or in other contexts.

Challenges facing the management of wastewater treatment systems in Chinese rural areas

The water environment in Chinese rural areas has seriously deteriorated to the extent that the development of rural areas is now under threat. To deal with this issue, the Chinese government has been promoting wastewater treatment systems (WTS) in rural areas since 2005. However, some of these wastewater treatment plants have shut down after just a few years. Thus, even though the number of newly built plants in rural areas has been rapidly increasing, the failure of these plants can impede the development of an efficient wastewater treatment in Chinese rural areas. This paper investigates the challenges faced by the management of the constructed wastewater treatment plants in Chinese rural areas using the case study method. Two cases, of Zhejiang and Hainan provinces, were analysed separately; the operation was successful in the former province and a failure in the latter one. The study demonstrates that the WTS in rural areas are faced with diverse implementation challenges, ranging from unsustainable financial sources for operation and maintenance cost to inappropriate governance structure, potential risks due to the local leadership rotation system of the government, limited participation by farmers in the management and technical complexity.

Integrated Cycles for Urban Biomass as a Strategy to Promote a CO2-Neutral Society—A Feasibility Study

The integration of closed biomass cycles into residential buildings enables efficient resource utilization and avoids the transport of biowaste. In our scenario called Integrated Cycles for Urban Biomass (ICU), biowaste is degraded on-site into biogas that is converted into heat and electricity. Nitrification processes upgrade the liquid fermentation residues to refined fertilizer, which can be used subsequently in house-internal gardens to produce fresh food for residents. Our research aims to assess the ICU scenario regarding produced amounts of biogas and food, saved CO2 emissions and costs, and social–cultural aspects. Therefore, a model-based feasibility study was performed assuming a building with 100 residents. The calculations show that the ICU concept produces 21% of the annual power (electrical and heat) consumption from the accumulated biowaste and up to 7.6 t of the fresh mass of lettuce per year in a 70 m2 professional hydroponic production area. Furthermore, it saves 6468 kg CO2-equivalent (CO2-eq) per year. While the ICU concept is technically feasible, it becomes economically feasible for large-scale implementations and higher food prices. Overall, this study demonstrates that the ICU implementation can be a worthwhile contribution towards a sustainable CO2-neutral society and decrease the demand for agricultural land.

Practical Performance and User Experience of Novel DUAL-Flush Vacuum Toilets

Vacuum toilets have gained increasing attention in circular urban development projects, because of their marked water saving qualities compared to conventional flush toilets and the increased resource recovery potential for energy in the form of biogas and phosphorous as, e.g., struvite from the resulting concentrated wastewater. A further reduction of the flushing volume of vacuum toilets would also bring nitrogen recovery options in reach. In the framework of the EU Horizon 2020 project Run4Life, a novel dual-flush vacuum toilet was developed and tested at two sites and combined with an analysis of the flushing patterns and a qualitative user survey. The results show that a 25–50% lower flushing water consumption and accordingly 1.5–2 times higher nutrient concentrations are achievable with this novel type of vacuum toilet. The usage frequency of the dual flush feature was higher in residential homes than in an office building, which also had urinals installed at the men toilets. A notable fraction of toilet visits in which the toilet was flushed twice as well as user feedback on dissatisfactory cleaning effects suggest that the applied reduction in water use is most likely the upper limit of what can be achieved in this type of toilet.

Institutional Barriers to On-Site Alternative Water Systems: A Conceptual Framework and Systematic Analysis of the Literature

Scientists are increasingly exploring on-site water systems to supplement conventional centralized water and wastewater infrastructure. While major technological advancements have been achieved, we still lack a systematic view on the non-technical, or institutional, elements that constitute important barriers to the uptake of on-site urban water management systems. This paper presents a conceptual framework distinguishing between institutional barriers in six key dimensions: Equity, Knowledge and Capabilities, Financial Investment, Legal and Regulatory Frameworks, Legitimacy, and Market Structures. The analysis of the existing literature covering these barriers is translated into a typology of the socio-technical complexity of different types of alternative water systems (e.g., non-potable reuse, rainwater systems, and nutrient recovery). Findings show that socio-technical complexity increases with the pollution load in the source water, correlating to potential health risk, and the number of sectors involved in the value chain of an alternative water system. For example, greywater reuse for toilet flushing might have systematically less complex institutional barriers than source separation for agricultural reuse. This study provides practitioners with easily accessible means of understanding non-technical barriers for various types of on-site reuse systems and provides researchers with a conceptual framework for capturing socio-technical complexity in the adoption of alternative water systems.

Willingness among food consumers to recycle human urine as crop fertiliser: Evidence from a multinational survey

Source-separating sanitation systems offer the possibility of recycling nutrients present in wastewater as crop fertilisers. Thereby, they can reduce agriculture's impacts on global sources, sinks, and cycles for nitrogen and phosphorous, as well as their associated environmental costs. However, it has been broadly assumed that people would be reluctant to perform the new sanitation behaviours that are necessary for implementing such systems in practice. Yet, few studies have tried to systematically gather evidence in support of this assumption. To address this gap, we surveyed 3763 people at 20 universities in 16 countries using a standardised questionnaire. We identified and systematically assessed cross-cultural and country-level explanatory factors that were strongly associated with people's willingness to consume food grown using human urine as fertiliser. Overall, 68% of the respondents favoured recycling human urine, 59% stated a willingness to eat urine-fertilised food, and only 11% believed that urine posed health risks that could not be mitigated by treatment. Most people did not expect to pay less for urine-fertilised food, but only 15% were willing to pay a price premium. Consumer perceptions were found to differ greatly by country and the strongest predictive factors for acceptance overall were cognitive factors (perceptions of risks and benefits) and social norms. Increasing awareness and building trust among consumers about the effectiveness of new sanitation systems via cognitive and normative messaging can help increase acceptance. Based on our findings, we believe that in many countries, acceptance by food consumers will not be the major social barrier to closing the loop on human urine. That a potential market exists for urine-fertilised food, however, needs to be communicated to other stakeholders in the sanitation service chain.

Hybrid constructed wetlands as post-treatment of blackwater: An assessment of the removal of antibiotics

New sanitation systems have been developed to treat, recover energy and nutrients, and permit reuse processes at the source of generation, minimizing water use and flow segregation. Thus, this study was carried out with the objective of evaluating the potential of hybrid constructed wetlands in the removal of organic matter, nutrients, pathogenic microorganisms, and 12 antibiotics from blackwater previously treated by an upflow anaerobic sludge blanket reactor. A hybrid system of constructed wetlands was used, comprised of a horizontal subsurface flow constructed wetland with a total volume of 0.60 m³ followed by a vertical subsurface flow constructed wetland with a total volume of 0.20 m³. Three different hydraulic retention times were comparatively tested (1.0, 2.0, and 3.0 days for the horizontal subsurface flow constructed wetland, and 1.1, 0.9, and 0.4 days for the vertical subsurface flow constructed wetland) in four distinct stages. The plant species used was Canna x generalis. The results from this study demonstrate the potential of constructed wetlands as a suitable technology for post-treatment of segregated domestic wastewater (anaerobically-digested blackwater). Efficient reduction of COD, BOD₅, total nitrogen, and total phosphorus (74, 93, 50, and 61%, respectively) was achieved, with a hydraulic retention time of 3.0 and 1.1 days for horizontal and vertical subsurface flow constructed wetland, respectively (stage IV). The presence of ciprofloxacin was confirmed by chromatographic and mass spectrometric analysis in an average concentration of 442.6 ng.L^-1 at the inflow of the horizontal subsurface flow constructed wetland, but was not observed at the outflow.

"Who Cares?": The Acceptance of Decentralized Wastewater Systems in Regions without Water Problems

There is a growing interest in decentralized wastewater treatment systems, especially in regions with water scarcity problems or water management issues. This study aims to determine whether the perceived advantages and disadvantages (leading to acceptance) of decentralized wastewater plants in such regions are the same in regions where the population is not aware of these water issues. Firstly, this study systematically reviews previous findings on public perceptions of the acceptance of decentralized wastewater treatment systems. Then, the study details the results of a focus group study to determine whether the elements identified in the literature are also relevant in a region where people are unaware of water problems. The results show that a lack of awareness of water issues seems to be a critical factor influencing acceptance. Reframing the usefulness of these systems by focusing on other aspects, such as environmental sustainability, is key.

A framework for resource recovery from wastewater treatment plants in megacities of developing countries

In developing countries, there is often a lack of a comprehensive data set that supports the development of coherent policies on resource recovery from wastewater treatment. This paper aims to contribute to the elaboration of resource recovery projects by providing accurate and updated data from wastewater treatment plants such as those located in the region of the Macrometropolis of Sao Paulo. The authors discuss possibilities of improvement of resource recovery for this illustrative example. Comprehensive analyses were performed based on data from 143 municipal wastewater treatment plants to understand the situation regarding resource recovery implementation in this region. The results show that just 26% of the plants perform at least one resource recovery practice. The predominant resource recovery practice is internal water reuse, and recovery is concentrated more in large plants than in medium and small ones. The sludge is disposed in landfills except for three plants, which perform sludge recycling for compost. Some plant managers reported interest in recovering energy from biogas, in expanding water reuse and in recovering sludge for fertilizer production or for building materials. Several aspects that have been regarded as relevant to the implementation of resource recovery processes in previous literature are discussed, such as the size of the plant, related legislation as well as treatment technologies and configurations. Finally, the authors propose a generic framework with several steps that can help to achieve resource recovery implementation. Therefore, the results can provide support for planning of resource recovery projects for large cities in developing countries.

Nutrient and pathogen removal from anaerobically treated black water by microalgae

The demand for systems that efficiently and sustainably recover value-added compounds and materials from waste streams is a major challenge. The use of wastewater as a source for recovery of carbon and nutrients is an attractive and sustainable alternative. In this study, anaerobically treated black water was treated in photobioreactors (PBRs) inoculated with Chlorella sorokiniana, and the process was investigated in terms of phosphorus and nitrogen removal, biomass growth, and the removal of pathogens. The consumption of bicarbonate (alkalinity) and acetate (volatile fatty acids) as carbon sources by microalgae was investigated. The average nutrient removal achieved was 66% for N and 74% for P. A high consumption of alkalinity (83%) and volatile organic acids (76%) was observed, which suggests that these compounds were used as a source of carbon. The biomass production was 73 mg L^-1 day^-1, with a mean biomass of 0.7 g L^-1 at the end of the batch treatment. At the end of the experiments, a log removal/inactivation of 0.51 log for total coliforms and 2.73 log for Escherichia coli (E. coli) was observed. The configuration used, a flat-panel PBR operated in batch mode without CO₂ supplementation, is a cost-effective and environmentally sustainable method for recovering of nutrients and production of algal biomass.

Explaining social acceptance of a municipal waste incineration plant through sociodemographic and psycho-environmental variables

Municipal waste incineration plants (MWIPs) are a source of emission of diverse pollutants that have been associated with environmental and health effects, mainly in relation to premises that are old and not well equipped or maintained. As a result, the public usually holds a negative view of such plants and tends to react adversely to construction of new plants. Understanding a population's perceptions is key to ensuring the correct development of such infrastructure and adequately managing population health concerns and behaviours. In this study, we surveyed 173 residents living close (≤ 10 km) to an MWIP being built in San Sebastian (Gipuzkoa, Spain) and 164 living further away (>10 km). The questionnaire included sociodemographic and psycho-environmental measures. Answers to the questionnaire revealed a fairly low acceptance rate and the perception of a high risk for human health and the environment (average scores of 0.57, 3.07 and 2.89 respectively in a 0 to 4 scale), with no statistically significant differences between people living nearby and further afield. A hierarchical regression model built to explore the public's acceptance of the MWIP explained 59% of the variance. Dominance and relative weight analyses revealed that the most important predictors of acceptance were trust in the information provided by the local government and perceived risk for human health, which accounted for 33.7% and 27.4% of the variance explained by the model respectively. Preference for landfilling and MWIP acceptance in a farther location made a less relevant contribution.

Social Influence, Risk and Benefit Perceptions, and the Acceptability of Risky Energy Technologies: An Explanatory Model of Nuclear Power Versus Shale Gas

Risky energy technologies are often controversial and debates around them are polarized; in such debates public acceptability is key. Research on public acceptability has emphasized the importance of intrapersonal factors but has largely neglected the influence of interpersonal factors. In an online survey (N = 948) with a representative sample of the United Kingdom, we therefore integrate interpersonal factors (i.e., social influence as measured by social networks) with two risky energy technologies that differ in familiarity (nuclear power vs. shale gas) to examine how these factors explain risk and benefit perceptions and public acceptability. Findings show that benefit perceptions are key in explaining acceptability judgments. However, risk perceptions are more important when people are less familiar with the energy technology. Social network factors affect perceived risks and benefits associated with risky energy technology, hereby indirectly helping to form one's acceptability judgment toward the technology. This effect seems to be present regardless of the perceived familiarity with the energy technology. By integrating interpersonal with intrapersonal factors in an explanatory model, we show how the current "risk-benefit acceptability" model used in risk research can be further developed to advance the current understanding of acceptability formation.

A Systematic Literature Review of Concepts and Factors Related to Pro-Environmental Consumer Behaviour in Relation to Waste Management Through an Interdisciplinary Approach

Although there has been a steady increase in the number of studies on consumer behaviour in relation to sustainable development, there is limited focus on the product disposal phase. This systematic literature review intends to: (1) clarify how concepts related to pro-environmental consumer behaviour are understood and analysed in the academic literature on waste management; (2) discover any interplay between pro-environmental consumer behaviour and generic consumer behaviour, and the conditions and factors that favour it. A typical systematic literature review methodology was applied to the papers available on Web of Science, Science Direct and EBSCO (Elton Bryson Stephens Company) host between 1975 and 2019, leading to the selection of 699 final papers. The findings reveal that: (1) Although scholars tend to create a variety of pro-environmental consumer behaviour models depending on their specific field of inquiry, all approaches can be traced back to a limited number of reference theories; (2) The overall level of interplay between pro-environmental consumer behaviour and generic consumer behaviour is limited, nevertheless a favourable context or a supportive institutional-legal framework can significantly influence it; (3) A plethora of conditions and factors favour this type of interplay, involving social psychology, laws, economics, institutions and more; (4) Several critical issues appear in the analysed papers, especially some scholars’ assumptions to be able to identify all key factors. It follows the need for a more interdisciplinary approach, a deeper analysis of the effectiveness of the intervention measures at the governmental and institutional level, and a clear classification of factors and conditions (as proposed by this review).

Hydroeconomic modeling of resource recovery from wastewater: Implications for water quality and quantity management

Emerging technologies and practices allow wastewater treatment facilities to recover valuable resources such as nutrients, energy, and recycled water during the wastewater treatment process. The ability to recover resources from wastewater introduces new tradeoffs in both water quality and quantity management. In particular, the fact that communities can obtain revenue from the sale of resources that are recovered from wastewater may help internalize the externalities of insufficient wastewater treatment. In this paper, we develop a theoretical model to characterize these tradeoffs within a hydroeconomic framework of optimal wastewater treatment with resource recovery, which is particularly well suited for applications in nutrient management. We use this model to derive analytical results that describe the economically optimal level of deployment, accounting for the fact that the technology or practice is costly and it generates benefits in the form of revenue from the recovered resource, as well as other societal benefits, such as improvements in human and ecosystem health. In addition, we present two examples using specific functional forms for treatment costs to demonstrate how the model can be applied to obtain general principles regarding societally optimal deployment. Our hydroeconomic framework can be used to explore the socioeconomic implications of strategies that target deployment of wastewater treatment with resource recovery, especially nutrients, at multiple scales.

Consumers' Acceptance of Agricultural Fertilizers Derived from Diverted and Recycled Human Urine

Nitrogen and phosphorus are essential ingredients in fertilizers used to produce food. Novel methods are emerging for more efficiently sourcing these nutrients, one of which is to recover them from recycled human urine; once recovered, N and P can be redirected to fertilizer production. While the technology for creating human urine-derived fertilizer (HUDF) exists, implementing it at scale will depend on public acceptance. Thus, this study examined U.S. consumers' acceptance of HUDF across a range of applications and, in comparison, to other fertilizer types. Data were collected from a representative national sample, and analyses of variance with post-hoc comparisons were conducted to compare across fertilizer applications and types. A hierarchical regression was conducted to assess if demographics, psychological variables, and value orientations predict HUDF acceptance. Results suggest that HUDF and biosolid-based fertilizers are equally preferred and more strongly preferred than synthetic fertilizers. HUDF is not preferred as strongly as organic fertilizers. HUDF was deemed most acceptable when used on nonedible plants and least acceptable when used on crops for human consumption. Regression analysis revealed that judgments about risks and benefits were the strongest predictors of acceptance of UDF use. These results are promising for sanitation practitioners and regulators among others.

Black water treatment by an upflow anaerobic sludge blanket (UASB) reactor: a pilot study

Decentralized sanitary wastewater treatment has become a viable and sustainable alternative, especially for developing countries and small communities. Besides, effluents may present variations in chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total nitrogen values. This study describes the feasibility of using a pilot upflow anaerobic sludge blanket (UASB) reactor to treat wastewater with different organic loads (COD), using black water (BW) and sanitary wastewater, in addition to its potential for preserving nutrients for later recovery and/or reuse. The UASB reactor was operated continuously for 95 weeks, with a hydraulic retention time of 3 days. In Phase 1, the reactor treated simulated BW and achieved 77% COD_total removal. In Phase 2, treating only sanitary wastewater, the COD_total removal efficiency was 60%. Phase 3 treated simulated BW again, and COD_total removal efficiency was somewhat higher than in Phase 1, reaching 81%. In Phase 3, the removal of pathogens was also evaluated: the efficiency was 1.96 log for Escherichia coli and 2.13 log for total coliforms. The UASB reactor was able to withstand large variations in the organic loading rate (0.09-1.49 kg COD m^-3 d^-1), in continuous operation mode, maintaining a stable organic matter removal.

What do consumers think about recycling human urine as fertiliser? Perceptions and attitudes of a university community in South India

Sanitation systems based on source separation and valorisation of human urine can improve the environmental sustainability of wastewater management. Yet, the social acceptability of such new, resource-oriented sanitation practices have not been assessed systematically. We attempt to address this research gap by reporting the findings of a survey conducted at a South Indian university that evaluated support for urine recycling among 1252 Indian consumers. We place our findings in the context of the Theory of Planned Behaviour, quantify consumer attitude to urine recycling through an exploratory numerical approach, and identify explanatory factors that shape consumer beliefs and perceptions. Overall, a moderately positive attitude was observed: 68% stated human urine should not be disposed but recycled, 55% considered it as fertiliser, but only 44% would consume food grown using it. While 65% believed using urine as crop fertiliser could pose a health risk, majority (80%) believed it could be treated so as to not pose a risk. The respondents' 'willingness to consume' urine-fertilised food was found to be strongly influenced by their willingness to pay. Consumer environmental attitudes, as evaluated using the New Ecological Paradigm scale, did not influence their attitude towards urine recycling behaviour. We thus believe that simply appealing to people's environmental sensitivities is not enough for introducing environmentally-friendly technologies like urine recycling, but that more targeted marketing messages are needed. We find sufficient support among our surveyed consumers for urine recycling but highlight that further research is needed to identify what information and agency will help translate positive attitudes into action and behaviour.

The Economics of Wastewater Treatment Decentralization: A Techno-economic Evaluation

The existing wastewater treatment infrastructure has not adequately established an efficient and sustainable use of energy, water, and nutrients. A proposed scheme based on source separation and water-efficient use is compared to the current wastewater management paradigm (one largely based on activated sludge) using techno-economic terms. This paper explores the economic viability of adopting more sustainable management alternatives and expands the understanding of the economics of decentralization and source-separation. The feasibility of three different potential types of source-separation (with different levels of decentralization) are compared to the conventional centralized activated sludge process by using recognized economic assessment methodologies together with widely accepted modeling tools. The alternatives were evaluated for two common scenarios: new developments and retrofit due to the aging of existing infrastructures. The results prove that source-separated alternatives can be competitive options despite existing drawbacks (only when countable incomes are included), while the hybrid approach resulted in the least cost-effective solution. A detailed techno-economic evaluation of the costs of decentralization provides insight into the current constraints concerning the paradigm shift and the cost of existing technologic inertia.