Greater New Orleans is surrounded by wetlands, the Mississippi River and two lakes. Excess rain can only be drained off with pumping systems or by evaporation due to the bowl-like shape of a large part of the city. As part of the solution to make New Orleans climate adaptive, green infrastructure has been implemented that enable rainfall infiltration and evapotranspiration of stored water after Hurricane Katrina in 2005. The long-term efficiency of infiltrating water under sea level with low permeable soils and high groundwater tables is often questioned. Therefore, research was conducted with the full-scale testing method measuring the infiltration capacity of 15 raingardens and 6 permeable pavements installed in the period 2011–2022. The results show a high variation of empty times for raingardens and swales: 0.7 to 54 m/d. The infiltration capacity decreased after saturation (ca 30% decrease in empty time after refilling storage volume) but all the tested green infrastructure met the guideline to be drained within 48 h. This is in contrast with the permeable pavement: only two of the six tested locations had an infiltration capacity higher than the guideline 10 inch/h (254 mm/h). The results are discussed with multiple stakeholders that participated in ClimateCafe New Orleans. Whether the results are considered unacceptable depends on a number of factors, including its intended purpose, site specific characteristics and most of all stakeholder expectations and perceptions. The designing, planning and scheduling of maintenance requirements for green infrastructure by stormwater managers can be carried out with more confidence so that green infrastructure will continue to perform satisfactorily over the intended design life and can mitigate the effects of heavy rainfall and droughts in the future.
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Current methods for energy diagnosis in heating, ventilation and air conditioning (HVAC) systems are not consistent with process and instrumentation diagrams (P&IDs) as used by engineers to design and operate these systems, leading to very limited application of energy performance diagnosis in practice. In a previous paper, a generic reference architecture – hereafter referred to as the 4S3F (four symptoms and three faults) framework – was developed. Because it is closely related to the way HVAC experts diagnose problems in HVAC installations, 4S3F largely overcomes the problem of limited application. The present article addresses the fault diagnosis process using automated fault identification (AFI) based on symptoms detected with a diagnostic Bayesian network (DBN). It demonstrates that possible faults can be extracted from P&IDs at different levels and that P&IDs form the basis for setting up effective DBNs. The process was applied to real sensor data for a whole year. In a case study for a thermal energy plant, control faults were successfully isolated using balance, energy performance and operational state symptoms. Correction of the isolated faults led to annual primary energy savings of 25%. An analysis showed that the values of set probabilities in the DBN model are not outcome-sensitive. Link to the formal publication via its DOI https://doi.org/10.1016/j.enbuild.2020.110289
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The results obtained in this study are encouraging and important for the implementation of permeable pavement and swales in The Netherlands, since the performance of SUDS in delta areas and in areas in the world with comparable hydraulic circumstances has been viewed with skepticism. The research undertaken on Dutch SUDS field installations has demonstrated with new, full scale monitoring methods that most of the bioretention swales and permeable pavements tested in this study meet the required hydraulic performance levels even after years in operation and without maintenance. Standardized tests of sedimentation devices however demonstrated that these facilities have a limited effectiveness for particles smaller than 60 µm while receiving a normal hydraulic loading. The applied methods of full scale testing of SUDS can easily be applied to observe the hydraulic performance of swales and permeable pavement after years of operation. Innovative monitoring methods and visualization of these experiments using video footage allows real-time observation of the entire infiltration process. Recording these observations in a logbook can provide insight in their demand of maintenance and can also help to improve their design.
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Evaluation of the hydrological performance of grassed swales usually needs long-term monitoring data. At present, suitable techniques for simulating the hydrological performance using limited monitoring data are not available. Therefore, current study aims to investigate the relationship between saturated hydraulic conductivity (Ks) fitting results and rainfall characteristics of various events series length. Data from a full-scale grassed swale (Enschede, the Netherlands) were utilized as long-term rainfall event series length (95 rainfall events) on the fitting outcomes. Short-term rainfall event series were extracted from these long-term series and used as input in fitting into a multivariate nonlinear model between Ks and its influencing rainfall indicators (antecedent dry days, temperature, rainfall, rainfall duration, total rainfall, and seasonal factor (spring, summer, autumn, and winter, herein refer as 1, 2, 3, and 4). Comparison of short-term and long-term rainfall event series fitting results allowed to obtain a representative short-term series that leads to similar results with those using long-term series. A cluster analysis was conducted based on the fitting results of the representative rainfall event series with their rainfall event characteristics using average values of influencing rainfall indicators. The seasonal index (average value of seasonal factors) was found to be the most representative short rainfall event series indicator. Furthermore, a Bayesian network was proposed in the current study to predict if a given short-term rainfall event series is representative. It was validated by a data series (58 rainfall events) from another full-scale grassed swale located in Utrecht, the Netherlands. Results revealed that it is quite promising and useful to evaluate the representativeness of short-term rainfall event series used for long-term hydrological performance evaluation of grassed swales.
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This study evaluated the performance of anaerobic co-digestion of cow manure (CM) and sheep manure (SM) in both batch and continuous digesters at 37 °C. Synergistic effects of co-digesting CM and SM at varying volatile solids (VS) ratios (1:0, 0:1, 3:1, 1:1, 1:3) were observed in the batch experiment, with the most effective degradation of cellulose (56%) and hemicellulose (55%), and thus, the highest cumulative methane yield (210 mL/gVSadded) obtained at a CM:SM ratio of 1:3. Co-digesting CM and SM improved the hydrolysis, as evidenced by the cellulase brought by SM and the increases of cellulolytic bacteria Clostridium. Besides, co-digestion enhanced the acidogenesis and methanogenesis, reflected by the enrichment of syntrophic bacteria Candidatus Cloacimonas and hydrogenotrophic archaea Methanoculleus (Coenzyme-B sulfoethylthiotransferase). When testing continuous digestion, the methane yield increased from 146 mL/gVS/d (CM alone) to 179 mL/gVS/d (CM:SM at 1:1) at a constant organic loading rate (OLR) of 1g VS/L/d and a hydraulic retention time (HRT) of 25 days. Furthermore, the anaerobic digestion process was enhanced when the daily feed changed back to CM alone, reflected by the improved daily methane yield (159 mL/VS/d). These results provided insights into the improvement of methane production during the anaerobic digestion of animal manure.
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Infiltrating pavements are potentially effective climate adaptation measures to counteract arising challenges related to flooding and drought in urban areas. However, they are susceptible to clogging causing premature degradation. As part of the Dutch Delta Plan, Dutch municipalities were encouraged to put infiltrating pavements into practice. Disappointing experiences made a significant number of municipalities decide, however, to stop further implementation. A need existed to better understand how infiltrating pavements function in practice. Through 81 full-scale infiltration tests, we investigated the performance of infiltrating pavements in practice. Most pavements function well above Dutch and international standards. However, variation was found to be high. Infiltration rates decrease over time. Age alone, however, is not a sufficient explanatory factor. Other factors, such as environmental or system characteristics, are of influence here. Maintenance can play a major role in preserving/improving the performance of infiltrating pavements in practice. While our results provide the first indication of the functioning of infiltrating pavement in practice, only with multi-year measurements following a strict monitoring protocol can the longer-term effects of environmental factors and maintenance actually be determined, providing the basis for the development of an optimal maintenance schedule and associated cost–benefit assessments to the added value of this type of climate adaptation.
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The Heating Ventilation and Air Conditioning (HVAC) sector is responsible for a large part of the total worldwide energy consumption, a significant part of which is caused by incorrect operation of controls and maintenance. HVAC systems are becoming increasingly complex, especially due to multi-commodity energy sources, and as a result, the chance of failures in systems and controls will increase. Therefore, systems that diagnose energy performance are of paramount importance. However, despite much research on Fault Detection and Diagnosis (FDD) methods for HVAC systems, they are rarely applied. One major reason is that proposed methods are different from the approaches taken by HVAC designers who employ process and instrumentation diagrams (P&IDs). This led to the following main research question: Which FDD architecture is suitable for HVAC systems in general to support the set up and implementation of FDD methods, including energy performance diagnosis? First, an energy performance FDD architecture based on information embedded in P&IDs was elaborated. The new FDD method, called the 4S3F method, combines systems theory with data analysis. In the 4S3F method, the detection and diagnosis phases are separated. The symptoms and faults are classified into 4 types of symptoms (deviations from balance equations, operating states (OS) and energy performance (EP), and additional information) and 3 types of faults (component, control and model faults). Second, the 4S3F method has been tested in four case studies. In the first case study, the symptom detection part was tested using historical Building Management System (BMS) data for a whole year: the combined heat and power plant of the THUAS (The Hague University of Applied Sciences) building in Delft, including an aquifer thermal energy storage (ATES) system, a heat pump, a gas boiler and hot and cold water hydronic systems. This case study showed that balance, EP and OS symptoms can be extracted from the P&ID and the presence of symptoms detected. In the second case study, a proof of principle of the fault diagnosis part of the 4S3F method was successfully performed on the same HVAC system extracting possible component and control faults from the P&ID. A Bayesian Network diagnostic, which mimics the way of diagnosis by HVAC engineers, was applied to identify the probability of all possible faults by interpreting the symptoms. The diagnostic Bayesian network (DBN) was set up in accordance with the P&ID, i.e., with the same structure. Energy savings from fault corrections were estimated to be up to 25% of the primary energy consumption, while the HVAC system was initially considered to have an excellent performance. In the third case study, a demand-driven ventilation system (DCV) was analysed. The analysis showed that the 4S3F method works also to identify faults on an air ventilation system.
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As the field of climate adaptation has entered an implementation and acceleration phase, measures for urban water and heat management are rapidly spreading in cities across the globe. Especially nature-based solutions have seen a recent rise in implementation to fight flooding, heat, drought, and biodiversity loss. Despite decades of experience, there is still a lot unknown about the long-term functioning of these measures and how this relates to design, development, and maintenance decisions. To this end, this chapter explores the relations between characteristics and performances of urban nature-based solutions, based on empirical research conducted in over 50 swales throughout the Netherlands between 2021 and 2022. The research combined various fieldwork methods such as full-scale infiltration tests to assess the hydraulic functionality and heavy metal accumulation tests by using an XRF-scanner, as well as neighborhood surveys to assess local perceptions of these swales and their functions. This chapter describes and illustrates these approaches for mapping and assessing the performance of swales, followed by a reflection on their suitability for linking design choices and performance indicators. Based on national guidelines, these indicators help to establish minimal performance quotas to evaluate and compare the performance of swales. While most of the researched swales met national criteria for hydraulic performance, almost a third of investigated swales exceeded norms for heavy metal accumulation. By building up a national database of swales and data derived through measurements, we attempt to find patterns among successes and failures in swale design through cross-case comparison, but conclude that these heavily rely on local circumstances and context-depending design choices. Expanding on mapping, assessment, and evaluation approaches can lead to a better understanding of these context-depending chances and risks for developing nature-based solutions.
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SummaryConstructed wetlands have been used for decades on industrial areas to treat stormwater. European regulations and local ambitions for water quality dictate lower emissions before the water is discharged to the drainage system, surface water or infiltrated to ground water. The increase in the required removal efficiency requires a better understanding of the characteristics of pollutants and cost-effective performance of constructed wetlands. In this chapter detailed characteristics of stormwater from (industrial) areas is given together with monitored removal efficiencies and the cost of constructed wetlands. Some case studies with constructed wetlands are selected and reviewed in this chapter which can be regarded as Best Management Practices (BMPs). In most cases the constructed wetlands are not monitored in detail but perceived to be effective. Long-term performance, however, remains an issue. New monitoring techniques such as underwater drones and full scale testing can be applied to get new insights on optimizing the hydraulic capacity and removal efficiency of wetlands. Last but not least: international knowledge exchange on constructed wetlands and new monitoring techniques can be promoted by interactive online tools.
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We tested the hypothesis that in human ageing a decreased intramuscular acylcarnitine status is associated with (pre-)frailty, reduced physical performance and altered mitochondrial function. Results showed that intramuscular total carnitine levels and acetylcarnitine levels were lower in (pre-)frail old females compared to fit old females and young females, whereas no differences were observed in males. The low intramuscular acetylcarnitine levels in females correlated with low physical performance, even after correction for muscle mass (%), and were accompanied with lowered expression of genes involved in mitochondrial energy production and functionality. We concluded that in (pre-)frail old females, intramuscular total carnitine levels and acetylcarnitine levels are decreased, and this decrease is associated with reduced physical performance and low expression of a wide range of genes critical for mitochondrial function. The results stress the importance of taking sex differences into account in ageing research.
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