Wastewater and greywater reuse on irrigation in centralized and decentralized systems--an integrated approach on water quality, energy consumption and CO2 emissions

Wastewater and greywater have different scales of end-uses in irrigation in Portugal. Wastewater is treated in a central wastewater treatment plant and reused in public/private large areas of irrigation, like agriculture, public gardens and golf courses. On the contrary, greywater reuse is generally applied in in situ small scales, treated and used in the same place, generally in the production site. The main aim of this paper is to compare the two types of systems: a wastewater centralized reuse system (WWCRS) and a greywater decentralized reuse system (GWDRS) in terms of water quality, energy consumption and CO2 emissions. In this paper, the main characteristics of both streams are presented and the degree of treatment required in each stream is analyzed. The advantages and disadvantages of its reuse in different scales, in terms of water quality, energy consumption and CO2 emissions are discussed. A methodology to calculate the energy consumptions and CO2 emissions related to wastewater treatment that may be applied in different cases is presented. A hypothetical example of the two systems: one referring to a WWCRS and the other to a GWDRS is presented. The energy consumption and the CO2 emissions are analyzed and compared. The WWCRS needs a higher degree of treatment and so it spends more energy and leads to more CO2 emissions to the environment than the GWDRS that consumed between 11.8 and 37.5% of the energy consumed in the WWCRS considering the same number of inhabitants served.

Life cycle analysis of a new modular greening system

The construction and use of buildings represent about half of the extracted materials and energy consumption, and around one third of the water consumption and waste produced in the European Union. Therefore it is becoming more important to use sustainable materials that reduce the environmental impacts of construction, by conserving and using resources more efficiently. Green walls can be used as a sustainable strategy to reduce the environmental impact of buildings. The aim of this study is to evaluate the environmental impact of a new modular system for green roofs and green walls (Geogreen) which uses waste and sustainable materials in its composition. A life cycle analysis (LCA) is used to evaluate the long term environmental benefits of this system. The life cycle analysis (LCA) is carried according to ISO 14040/44 using GaBi software and CML 2001 impact category indicators. The adopted functional unit is the square meter of each material required to assemble the Geogreen system. This study also compares the environmental performance of the Geogreen system with other living wall systems and other cladding materials using data from the literature. This LCA study of the Geogreen system became relevant to identify a curing process with a major impact on GWP due to the energy consumed in this process. A change on this process allowed reducing 74% of the overall GWP. After this change it can be noticed that the Geogreen System presents one of the lowest environmental burden when compared to other construction systems.

Domestic water uses: characterization of daily cycles in the north region of Portugal

Nowadays, there is an increasing discussion among specialists about water use efficiency and the best measures to improve it. In Portugal, there have been a few attempts to expand the implementation of in situ water reuse projects. However, there is a lack of information about indoor water uses and how they are influenced by sociodemographic characteristics. There are several studies that investigate per capita global water usage, but the partitioning of this volume per domestic device and daily cycles is yet unknown. Identified as one of the key questions in sustainable building design, the water end-use is of primary importance to the design of hydraulic networks in buildings. In order to overcome this lack, a quantitative characterization of daily water uses for each domestic device was performed, based on a weekly monitoring program in fifty-two different dwellings in the northern region of Portugal (Vila Real, Valpaços and Oporto). For forty of them, each water usage of different domestic devices of each dwelling was recorded. At the same time, the remaining twelve dwellings were also monitored in order to register the volume of water consumed in each utilization of each domestic device. This paper presents the results of this complete monitoring program, using collected data to establish indoor water use patterns for each domestic device, aiming to support a more realistic approach to residential water use. The daily cycles in the different cities, where the monitoring program was performed, are also presented, in order to evaluate possible influences of sociodemographic characteristics.

Statistical analysis in MSW collection performance assessment

The increase of Municipal Solid Waste (MSW) generated over the last years forces waste managers pursuing more effective collection schemes, technically viable, environmentally effective and economically sustainable. The assessment of MSW services using performance indicators plays a crucial role for improving service quality. In this work, we focus on the relevance of regular system monitoring as a service assessment tool. In particular, we select and test a core-set of MSW collection performance indicators (effective collection distance, effective collection time and effective fuel consumption) that highlights collection system strengths and weaknesses and supports pro-active management decision-making and strategic planning. A statistical analysis was conducted with data collected in mixed collection system of Oporto Municipality, Portugal, during one year, a week per month. This analysis provides collection circuits' operational assessment and supports effective short-term municipality collection strategies at the level of, e.g., collection frequency and timetables, and type of containers.

Evaluation of operational, economic, and environmental performance of mixed and selective collection of municipal solid waste: Porto case study

This article describes an accurate methodology for an operational, economic, and environmental assessment of municipal solid waste collection. The proposed methodological tool uses key performance indicators to evaluate independent operational and economic efficiency and performance of municipal solid waste collection practices. These key performance indicators are then used in life cycle inventories and life cycle impact assessment. Finally, the life cycle assessment environmental profiles provide the environmental assessment. We also report a successful application of this tool through a case study in the Portuguese city of Porto. Preliminary results demonstrate the applicability of the methodological tool to real cases. Some of the findings focus a significant difference between average mixed and selective collection effective distance (2.14 km t(-1); 16.12 km t(-1)), fuel consumption (3.96 L t(-1); 15.37 L t(-1)), crew productivity (0.98 t h(-1) worker(-1); 0.23 t h(-1) worker(-1)), cost (45.90 € t(-1); 241.20 € t(-1)), and global warming impact (19.95 kg CO2eq t(-1); 57.47 kg CO2eq t(-1)). Preliminary results consistently indicate: (a) higher global performance of mixed collection as compared with selective collection; (b) dependency of collection performance, even in urban areas, on the waste generation rate and density; (c) the decline of selective collection performances with decreasing source-separated material density and recycling collection rate; and (d) that the main threats to collection route efficiency are the extensive collection distances, high fuel consumption vehicles, and reduced crew productivity.

Assessment strategies for municipal selective waste collection schemes

An important strategy to promote a strong sustainable growth relies on an efficient municipal waste management, and phasing out waste landfilling through waste prevention and recycling emerges as a major target. For this purpose, effective collection schemes are required, in particular those regarding selective waste collection, pursuing a more efficient and high quality recycling of reusable materials. This paper addresses the assessment and benchmarking of selective collection schemes, relevant to guide future operational improvements. In particular, the assessment is based on the monitoring and statistical analysis of a core-set of performance indicators that highlights collection trends, complemented with a performance index that gathers a weighted linear combination of these indicators. This combined analysis underlines a potential tool to support decision makers involved in the process of selecting the collection scheme with best overall performance. The presented approach was applied to a case study conducted in Oporto Municipality, with data gathered from two distinct selective collection schemes.

An exploratory study on the influence of socio-demographic characteristics on water end uses inside buildings

Any strategy of water demand management needs the collaboration of the population involved and so it is important to know how characteristics as residence area, number of residents, presence/absence of children/elders, income level, and educational level, among others, may influence the use of water. Empirical studies that quantify relationship between socio-demographic factors and the water end use patterns inside buildings are still largely lacking. To help to fill this gap this paper gathers information about the characterization of water end use per domestic device in three regions of north of Portugal with different socio-demographic characteristics. The main research goal was to establish indoor water end use patterns per domestic device and to evaluate possible relations between these patterns with the socio-demographic characteristics of the area where the household is, namely the number of residents, the presence/absence of children/elders, the income level and educational level. The washbasin is in average the domestic device with more number of uses in a day (responsible for 34% of the total use), close followed by the kitchen sink (32%), the toilet flush (23%), the bathtub (6%) and finally the dishwasher (3%) and the washing machine (2%). The results found might reflect differences in rural and urban lifestyles once that, with the exception of the kitchen sink, Valpaços is the city that registers the lowest number of uses in the appliances monitored. Significant correlations were found in the following cases: between the residence area and the number of uses in washbasin and in the toilet flush; between the presence of children in the household and the use in the dishwasher; between the income level and the number of uses in the washbasin, in the bathtub, in the washing machine and in the dishwasher.

Energy consumption, CO2 emissions and costs related to baths water consumption depending on the temperature and the use of flow reducing valves

In the domestic segment, various appliances and processes consume great amount of water and, consequently, energy. In this context, the main aim of this study is to analyse the impact of water temperature, flow and bath duration in water and energy consumptions. The impact on CO₂ emissions and a simple costs analysis were also carried out. It included a monitoring plan of 197 baths taken under different scenarios of water temperature and flow. It was concluded that increasing water consumption leads to an increase on energy consumption and that both resources consumptions increase with bath duration. Bath temperature had influence not only on energy consumption, as expected, but also in water consumption, what may be explained by the user's satisfaction during baths with higher temperatures. The use of a flow reducing valve is not a guarantee of water saving which can also be related to the user's satisfaction patterns, given that the introduction of a flow reducing valve can lead to a bath duration increase. In what concerns to the CO₂ emissions, it was concluded, as expected, that higher values are obtained for baths with higher temperatures given their relation with higher energy consumptions patterns. A simple costs analysis revealed that having flow reducing valves, with a bath temperature of 75 °C, increased the costs with electricity and water in 119% and 32%, respectively, when compared with a temperature of 60 °C.

Which are the factors that may explain the differences in water and energy consumptions in urban and rural environments?

Rural and urban environments present significant differences between water and energy consumptions. It is important to know, in detail, which factors related to the consumption of these two resources are different in both environments, once that will be those important to manage and discuss in order to improve its use efficiency and sustainability. This research work involves a survey whose aim is to find the factors that in rural and urban environments may justify the differences found in water and energy consumptions. Besides the collection of water and energy consumption data, this survey analyzed 80 variables (socio-demographic, economic, household characterization, among others), that were chosen among the bibliography as possible factors that should influence water and energy consumptions. After the survey application in rural and urban areas and the data statistical treatment, 42 variables remained as truly differentiating factors of rural and urban environments and so as possible determinants of water and energy consumptions. In order to achieve these objectives, a descriptive data analysis and statistical inference (Mann-Whitney-Wilcoxon test and the Chi-square test of homogeneity) were performed. All the 42 differentiating variables that result from this study may be able to justify these differences, however this will not be presented in the paper and it is reserved for future work.

An approach to the implementation of Low Impact Development measures towards an EcoCampus classification

Impervious cover has important hydrologic impacts, namely the increased runoff volume and peak discharges in the rainwater network, which can lead to significant consequences like rapid urban floods with social, environmental and economic implications. LID (Low Impact Development) consist of distributed runoff management measures, like green roofs, pervious pavements, waterways covered with vegetation and filter trails, among others, that seek to control stormwater in the origin, reducing imperviousness. These solutions avoid increased runoff rate and volume, increase infiltration and groundwater recharge. The main goal of the research work here presented is to study the hydrological impact of LID's in UTAD (University of Trás-os-Montes e Alto Douro) campus, which is an institution focused on sustainability, since it has defined in its Strategic Plan to achieve, in a near future, an EcoCampus classification. To achieve the proposed goal, the campus area was studied in detail in order to evaluate the technical possibility of LID's implementation. A peak discharge comparison was made between the current situation and the one with LID's implementation, using the rational method. The results showed that peak discharges reduction between 68 and 95% may be achieved with LID solutions in UTAD campus.

In situ evaluation of water and energy consumptions at the end use level: The influence of flow reducers and temperature in baths

Nowadays, water and energy consumption is intensifying every year in most of the countries. This perpetual increase will not be supportable in the long run, making urgently to manage these resources on a sustainable way. Domestic consumptions of water and electric energy usually are related and it's important to study that relation, identifying opportunities for use efficient improvement. In fact, without an understanding of water-energy relations, there are water efficiency measures that may lead to unintentional costs in the energy efficiency field. In order to take full advantage of combined effect between water and energy water management methodologies, it is necessary to collect data to ensure that the efforts are directed through the most effective paths. This paper presents a study based in the characterization, measurement and analysis of water and electricity consumption in a single family house (2months period) in order to find an interdependent relationship between consumptions at the end user level. The study was carried out on about 200 baths, divided in four different scenarios where the influence of two variables was tested: the flow reducer valve and the bath temperature. Data showed that the presence of flow reducer valve decreased electric energy consumption and water consumption, but increased the bath duration. Setting a lower temperature in water-heater, decreased electric consumption, water consumption and bath duration. Analysing the influence of the flow reducer valve and 60°C temperature simultaneously, it was concluded that it had a significant influence on electric energy consumption and on the baths duration but had no influence on water consumption.

Potential Use of the Theory of Vulnerability in Information Systems

Information Systems in the past few years became a keystone of society. History shows that in some Information Systems one simple failure can lead to disproportioned economic and social damages. Initially used in structural systems, the theory of vulnerability searches for this type of failure. This theory identifies failures in which small damage can have disproportionate impact consequences in terms of the functionality of the whole system. To test and evaluate these failures injections and analyze the impacts of them in sensitive Information Systems, simulation provides an interesting approach. By mimicking systems and representing them through models, simulation studies an imitated system without disrupting the system itself. Simulation provides a safer approach to explore and test the system in damage scenarios without real consequences. This paper discusses the use of the theory of vulnerability in Information Systems simulation.

Bibliometric analysis of global research trends on biomimetics, biomimicry, bionics, and bio-inspired concepts in civil engineering using the Scopus database

This paper presents a bibliometrics analysis aimed at discerning global trends in research on 'biomimetics', 'biomimicry', 'bionics', and 'bio-inspired' concepts within civil engineering, using the Scopus database. This database facilitates the assessment of interrelationships and impacts of these concepts within the civil engineering domain. The findings demonstrate a consistent growth in publications related to these areas, indicative of increasing interest and impact within the civil engineering community. Influential authors and institutions have emerged, making significant contributions to the field. The United States, Germany, and the United Kingdom are recognised as leaders in research on these concepts in civil engineering. Notably, emerging countries such as China and India have also made considerable contributions. The integration of design principles inspired by nature into civil engineering holds the potential to drive sustainable and innovative solutions for various engineering challenges. The conducted bibliometrics analysis grants perspective on the current state of scientific research on biomimetics, biomimicry, bionics, and bio-inspired concepts in the civil engineering domain, offering data to predict the evolution of each concept in the coming years. Based on the findings of this research, 'biomimetics' replicates biological substances, 'biomimicry' directly imitates designs, and 'bionics' mimics biological functions, while 'bio-inspired' concepts offer innovative ideas beyond direct imitation. Each term incorporates distinct strategies, applications, and historical contexts, shaping innovation across the field of civil engineering.

Water consumption assessment and classification in industrial buildings - The case study of Continental Advanced Antenna, Vila Real, Portugal

Water abstraction for the industrial, domestic, and agricultural sectors increased from 0.67 trillion m3/year in the 1900s to 3.79 trillion m3/year in 2000, and it is expected to increase by 55 % in 2050 when the majority of the world's population will live in urban areas. Concerning the industrial sector, despite the efforts to a more sustainable use, water is still an essential and irreplaceable resource, and this situation tends to increase due to modern industrial installations that require large-scale and complex water distribution systems. Usually, industries consume a large volume of water, however due to more and severer regulations, it is necessary to propose strategies for the aid of water conservation. This article presents a methodology to analyse, classify and optimize water consumption in industrial installations, using a real case study located in Vila Real, Portugal. The daily water consumption per worker, the daily record of use of each type of device and the hourly usage pattern were analysed and a classification was achieved according to the ANQIP (National Association for Quality in Building Installations) calculator. The case study revealed a great opportunity of improvement in what concerns to water efficient use. Some measures to improve the efficiency of water use in the building were pointed out, such as the use of rainwater harvesting systems, the use of aerators and replacements of taps and faucets when possible. The methodology is expeditious and user-friendly, and easy to replicate in similar cases, however it reveals some difficulties (especially in the data collection process that is made by inquiry, once it is always dependent on the respondent sensibility and willingness).

Permeable Asphalt Pavements (PAP): Benefits, Clogging Factors and Methods for Evaluation and Maintenance-A Review

Permeable asphalt pavement (PAP) is an efficient solution to stormwater management, allowing water to infiltrate through its layers. This reduces surface runoff and mitigates urban flooding risks. In addition to these hydrological benefits, PAP enhances water quality by filtering pollutants such as organic and inorganic materials and microplastics. However, clogging from sediment accumulation in the pavement's void structure often impairs its performance, reducing infiltration capacity. This review addresses several issues related to PAP, including the factors that contribute to pavement clogging and evaluates current and emerging maintenance strategies, including manual removal, pressure washing, regenerative air sweeping and vacuum truck utilization. Additionally, different methods of assessing clogging using innovative technology such as X-Ray Computed Tomography (CT), as well as a summary of the software used to process these images, are presented and discussed as tools for identifying clogging patterns, analyzing void structure and simulating permeability. This review identifies gaps in existing methodologies and suggests innovative approaches, including the creation of self-cleaning materials designed to prevent sediment buildup, biomimetic designs modeled after natural filtration systems and maintenance protocols designed for targeted clogging depths, to support the optimization of PAP systems and promote their adoption in resilient urban infrastructure designs in alignment with Sustainable Development Goals (SDGs).