Search Results (23)

It is anticipated that by 2028 there will be a significant increase in the use of HWHP systems in Great Britain (GB). Such systems are considered a better, energy-efficient alternative to fossil fuel-based burners and furnaces, as they use electricity. There are concerns that these systems are susceptible to microbial contamination because they hold water at lower temperatures. In particular, the concern is regarding Legionella contamination, as it can potentially cause disease in the general public and those who are maintaining and replacing these systems. Therefore, this review was focused on understanding the potential risk posed by their increased use and maintenance requirements. This review was approached systematically but was not a full systematic review. There were 61 papers that were considered potentially relevant to the research questions. Of these, 40 papers were considered relevant to the topic of Legionella in HWHP and underwent full article assessment and data extraction. The remaining papers were considered useful for background information. The scope of this review established that Legionella are a known risk in hot water systems that can be carried over to HWHP systems, yet there is minimal evidence to suggest that the current control measures are being appropriately applied to reduce the risk of exposure. When considering countrywide legislation and guidance, it appears that the risk is considered lower in single- or multi-family homes that do not require a centralised system. This review included the assessment of information regarding the safety of working with HWHP systems with regards to maintenance and replacement. The authors found a lack of information regarding these safety concerns. This review is among the first to systematically evaluate the risks of Legionella contamination in HWHP systems. Full article

As global urbanisation, industrialisation, and population growth escalate, the production of wastewater also increases, leading to significant water pollution on a global scale. This pollution poses severe threats to environmental health, wildlife, and human communities. In rural areas where centralised sewage systems are often absent, septic tanks play a crucial role in managing wastewater. They separate solids from liquids and facilitate the biological decomposition of organic matter. This paper utilises a Patent Landscape Review (PLR) to analyse the scope and direction of innovations in septic tank technology. Conducted on 23 September 2022, the patent search targeted filings from January 2001 through June 2022 to identify prevailing trends and advancements within this field. Through a detailed examination of 889 patents, categorised by keywords, processes, materials, and designs, this study offers a comprehensive overview of the patent landscape for septic tanks. Key findings indicate that fibreglass cylindrical tanks dominate the market due to their durability and efficiency. This review also highlights a growing trend towards modular septic systems, which offer scalable solutions adaptable to specific environmental conditions. Furthermore, some patents propose the repurposing of various objects as septic tanks, demonstrating a move towards sustainability by reducing waste and enhancing environmental conservation. This paper emphasises the importance of continued innovation in septic tank technology to address the challenges of effective wastewater management in underserved rural communities. Full article

In light of the challenges required by the European Green Deal policies concerning the achievement of climate neutrality by 2050, this paper analyses the suitability of different Italian urban systems for energy consumption and CO₂ emission reduction. In anthropised territories, there are strong relationships between energy consumption, climate-changing emissions and settlement patterns. Lands considered low could increase their rating because they have far greater environmental, energy and land resources than more pivotal ones. After an Italian-scale overview of the ecosystem capacities, this paper develops a detailed study of three exemplary areas: the northeast, the northwest, and the central-west coast. The analysis uses Burkhard’s matrix for ecosystem values and the energy consumption 2021 report of the National Energy Authority. The first finding is that the northeast region, characterised by spread and rarefied urbanisation, has a peculiar suitability for climate neutrality. In the results, spread territories perform much better than centralised ones. The coexistence of little urban cores, space for vegetation and a widespread water network promotes synergies for enhancing an ecosystem approach to land design. Full article

The environmentally and economically sustainable provision of safe drinking water remains one of the most significant public health challenges facing society. It is particularly difficult in small municipalities that lack the human and financial resources to maintain complex and/or expensive water treatment systems, especially in regions where the water is naturally contaminated with toxic substances such as arsenic. This paper analyses two municipalities (Kanjiža and Senta) in northern Serbia with groundwater arsenic concentrations significantly higher than the 10 µg/L maximum allowable concentration. Two different water supply approaches are compared: (1) local supply, where each settlement has their own treatment plant using existing sources; (2) creation of a centralised network, which connects several settlements together with better quality water sources. The analysis considers techno-economical aspects and the quantity and quality of available water, as well as the yields investment and exploitation cost projections for both approaches. The results demonstrate that for small municipalities, a holistic approach to decision making is necessary to find the best solutions for drinking water supply, which in the case of the two municipalities studied is connection to a centralised system supplied from better quality water sources and the creation of connections beyond municipal administrative boundaries. Full article

Demand-responsive control of electrically heated hot water storage tanks (HWSTs) is one solution, already present in the building stock, to stabilise volatile energy networks and markets. This has been put into sharp focus with the current energy crisis in Europe due to reduced access to natural gas. Furthermore, increasing proportions of intermittent renewable energy will likely add to this volatility. However, the adoption of demand response (DR) by consumers is highly dependent on the economic benefit. This study assesses the economic potential of DR of centralised HWSTs through both an analysis of spot price data and an optimisation algorithm approximating DR control. The methods are applied to a case study apartment building in Norway using current pricing models and examine the effect of the demand profile, electricity prices, heating power and storage capacity on energy cost and energy flexibility. Unit cost savings from DR are closely linked to the variation in unit energy price during the optimisation period. Increasing the storage capacity or the heating power increases the flexibility with a diminishing rate of return. However, increasing storage capacity does not result in cost savings as additional heat losses are greater than the saving from shifting demand, except for during highly volatile electricity price periods. Changing the minimum setpoint temperature improves the cost curve as a greater thermal storage capacity can be achieved without increasing heat loss. Systems utilising a smaller heating power are more economical due to the dominant role of the monthly price related to the peak energy demand of the system. Full article

The degradation of rivers in urban landscapes is alarming and impaired their ecological functions and the services they provide to society. In African cities, urban rivers are among the most degraded ecosystems, yet ecologically sustainable utilisation of river resources can contribute to and support sustainable urban development. In this paper, we identify and analyse key governance and institutional drivers of ecological change in urban river systems in the Swartkops catchment in South Africa and the Federal Capital Territory (FCT) in Nigeria. Our results indicate that poor ecological conditions of rivers in the two urban landscapes can be attributed to: (1) a lack of system view of the water value chain and associated infrastructure, (2) ambiguity in roles, responsibilities, and poor accountability, (3) prioritizing short-term social–economic–political agenda over long-term environmental sustainability goals, (4) institutional silos and failure of cooperative governance, and (5) over-centralised, top-down, state-centric governance processes. Strengthening the interactions between actors in the science, policy and practice domains, mainstreaming planning with rivers in integrated urban development plans, and strengthening cooperative and polycentric governance across administrative scales are key governance and institutional processes needed to address the trajectory of urban ecological degradation. Our paper sheds light on the fundamental role of strengthening governance and institutional processes for steering urban rivers toward sustainable paths for city resilience. Full article

The feasibility of installing rainwater harvesting systems in buildings is usually defined based primarily on economic analysis. In this perspective, we reviewed the literature related to water consumption in buildings, rainwater use, and environmental assessment tools to evaluate the impact of rainwater harvesting on the environment. Identifying water end uses in buildings showed a high potential for potable water savings through alternative sources (e.g., rainwater use for non-potable purposes). Most studies reviewed found potential for potable water savings from 20 to 65%. Moreover, the literature reported that rainwater harvesting systems might reduce the runoff volume from 13 to 91%. However, other possible benefits and impacts of the systems on water flow and the environment must be assessed in addition to the potential for rainwater harvesting. Life cycle assessment, life cycle cost assessment, and water balance modelling have been used in urban water management. Most life cycle studies reported that rainwater harvesting systems have better environmental performance than centralised systems. The water balance method may effectively determine the impacts these systems cause on the water cycle. Using life cycle assessment and the water balance method together is essential to evaluating rainwater harvesting systems integrated into the urban environment. Full article

Norfolk Island, like many islands in the subtropical Pacific, is at increasing risk of drought. To test the hypothesis that desalination is the most cost-effective technology for providing potable water during ‘water emergencies’, this study calculated and compared the levelised cost on Norfolk Island of seven ‘centralised’ intervention options and two ‘diffuse’ options for increasing groundwater accessions. Gully dams were the ‘centralised’ intervention option found to have the lowest levelised cost but had the largest percentage reductions in yield (i.e., 39% for 1 ML storage) under a projected drier future climate, greater than twice the percentage reduction in rainfall (16%) but less than the percentage reduction in runoff (44%). Cluster-scale roof-harvested rainwater systems with ‘turkey nest’ earth embankment had the second lowest levelised cost but are probably socially unacceptable due to siting on the community’s premier sporting oval. Desalination had the third lowest levelised cost, followed by the use of existing deep groundwater bores to pump and store water exclusively for use during a water emergency. Although desalination was not the most cost-effective technology, it is likely to be more socially acceptable than the two more cost-effective options. After gully dams, rainwater harvesting intervention options had the second highest proportional reductions in yield under a projected drier future climate (~10%); however, the reductions were less than the percentage reductions in rainfall. The yield from desalination and groundwater were unaffected under a drier future climate projected for ~2060. Full article

There are increasing international efforts to tackle climate change by reducing the emission of greenhouse gases. As such, the use of electrolytic hydrogen as an energy carrier in decentralised and centralised energy systems, and as a secondary energy carrier for a variety of applications, is projected to grow. Required green hydrogen can be obtained via water electrolysis using the surplus of renewable energy during low electricity demand periods. Electrolysis systems with alkaline and polymer electrolyte membrane (PEM) technology are commercially available in different performance classes. The less mature solid oxide electrolysis cell (SOEC) promises higher efficiencies, as well as co-electrolysis and reversibility functions. This work uses a bottom-up approach to develop a viable business model for a SOEC-based venture. The broader electrolysis market is analysed first, including conventional and emerging market segments. A further opportunity analysis ranks these segments in terms of business attractiveness. Subsequently, the current state and structure of the global electrolyser industry are reviewed, and a ten-year outlook is provided. Key industry players are identified and profiled, after which the major industry and competitor trends are summarised. Based on the outcomes of the previous assessments, a favourable business case is generated and used to develop the business model proposal. The main findings suggest that grid services are the most attractive business sector, followed by refineries and power-to-liquid processes. SOEC technology is particularly promising due to its co-electrolysis capabilities within the methanol production process. Consequently, an “engineering firm and operator” business model for a power-to-methanol plant is considered the most viable option. Full article

Water and wastewater services have been provided through centralised systems for more than a century. The operational and management approaches of the water systems face challenges induced by population growth, urbanisation, and ageing infrastructure. Recent advancements in water system engineering include the development of intelligent water networks. These intelligent networks address management and operational challenges associated with pressure and flow variations in the water network and it reduces the time for identification of pipe bursts and leakages. Research is required into the development of intelligent water networks to ensure consistent data collection and analysis that can filter and aggregate into actionable events to reduce water leakage, leakage cost, customer disruptions, and damages. Implementation of an intelligent algorithm with an integrated Supervisory Control and Data Acquisition (SCADA) system, high-efficiency smart sensors, and flow meters, including a tracking mechanism, will significantly reduce system management and operational issues and ensure improved service delivery for the community. This paper discusses the history of water systems, traditional water supply systems, need for intelligent water network, and design/development of the intelligent water networks. A framework for the intelligent water network has also been presented in this paper. Full article

This work reviews two mechanical separation technologies (screw press and decanting centrifuge) which could be used in the dairy, beef, pig and anaerobic digestion sectors in nutrient-vulnerable zones in order to improve the sustainability of manure and anaerobic digestate management by decreasing agricultural phosphorus loss and reducing environmental impact on water quality. Capital and operating costs, separation efficiency and throughput, and management and processing of separated fractions, including transport costs, environmental impacts and the biosecurity of separated solids for export, were considered. Of the two technologies reviewed, screw press separation is a more cost-effective option (5-fold cheaper per tonne of feedstock) when lower amounts of export of phosphorus off farm are acceptable. For farms and those with anaerobic digesters managing larger volumes of manure/digestate, screw press separation is possible. However if higher levels of phosphorus removal are required, the use of decanting centrifugation is a viable option. Centralised processing facilities could also make use of decanting centrifuge technology to act as processing hubs for local farms within a distance that makes it economical for transport of manure/treated manure to/from the processor (the maximum distance for economical transport of raw manure and separated solids is approximately 70 km and 84 km, respectively). Both separation technologies could be integrated into agricultural manure and digestate management systems in order to provide a more sustainable approach to managing agricultural phosphorus loss and its associated impact on water quality. Screw press and decanting centrifuge separation could reduce phosphorous loss to water bodies by 34% and from 30 to 93%, respectively. Full article

While rainwater harvesting can provide additional water resources, this approach is largely undertaken using water from roofs. More recently, the potential for using stormwater harvested from permeable pavements was recognised as a potential additional water resource. The objective of this study was to estimate the reduction of environmental impacts caused by traditional drainage systems and centralised water utilities if permeable pavement systems were used to harvest stormwater for nonpotable purposes in buildings. The lifecycle environmental impacts and costs associated with the proposed pavements and hydraulic systems were assessed. The city of Glasgow was chosen as a case study. We used the Netuno computer programme to estimate the potential for potable water savings considering the use of stormwater for nonpotable purposes and the SimaPro software to perform a lifecycle assessment (LCA). With the implementation of permeable pavements and stormwater utilisation, great reductions in lifecycle emissions (i.e., CO₂-, SO₂-, and PM_2.5-equivalent emissions) were observed. The proposed system also proved to be economically feasible, i.e., a payback period equal to 16.9 years. The results show the economic and environmental feasibility of permeable pavements when used on a large scale, proving to be an important strategy to reduce water and environmental stresses caused by centralised water utilities and traditional drainage systems. Full article

Socio-economic processes and climate change impact the socio-hydrology of many small towns in the Hindu Kush Himalaya (HKH), such as Leh in Ladakh. The rapidly urbanising town experienced a shift from agricultural livelihoods towards incomes mainly relying on the tourism sector. As results of this research show, the limited water resources essential to the everyday life of urban citizens have become increasingly important for the tourism sector and the urbanisation process. This study aims to understand the transformation of the urban mountain waterscape and the role of different actors involved. The waterscape approach frames hydro-social relations in a specific spatial context and additionally captures diverging hydromentalities within local actor constellations. Related discourses are materialised as water governance impacting the everyday life of urban citizens. A combination of quantitative, qualitative and participatory methods allows for a differentiated picture of current developments. Based on 312 household questionnaires, 96 semi-structured interviews, and a participatory photography workshop, this study provides evidence that urban restructuring induced by development imaginaries produces uneven water citizenships in Leh. Along with socio-economic shifts, the community-managed water regulation system is replaced by a technocratic scheme, centralising water supply and sanitation. While some of Leh’s citizens benefit from urban restructurings, others are confronted with environmental and social costs, such as a deteriorating water quality and a further reduction in quantity. Full article

Energy poverty can be defined as the inability to pay the bills that are required for maintaining the comfort conditions (usually in winter) in dwellings. The use of energy efficient systems is one way forward to mitigate this problem, with one option being the electrically driven air source heat pump water heater. This paper assesses the performance of a centralised heat pump (200 kW of heating capacity) to meet the space heating demand of block dwellings in Madrid (tier four out of five in winter severity in Spain). Two models have been developed to obtain the following variables: the hourly thermal energy demand and the off-design heat pump performance. The proposed heat pump is driven by a motor with variable rotational speed to modulate the heating capacity in an efficient way. A back-up system is also considered to meet the peak demand. A levelised cost of heating of 92.22 €/MWh is obtained for a middle-level energy efficiency in housing (class E, close to D). Moreover, the following energy-environmental parameters have been achieved: more than 74% share of renewable energy in primary energy and 131.7 g CO₂ avoided per kWh met. A reduction of 60% in the heating cost per dwelling is obtained if an energy retrofit is carried out, improving the energy performance class from E to C. These results prove that the proposed technology is among the most promising measures for addressing energy poverty in vulnerable households. Full article

Urban water systems face severe challenges such as urbanisation, population growth and climate change. Traditional technical solutions, i.e., pipe-based, grey infrastructure, have a single purpose and are proven to be unsustainable compared to multi-purpose nature-based solutions. Green Infrastructure encompasses on-site stormwater management practices, which, in contrast to the centralised grey infrastructure, are often decentralised. Technologies such as green roofs, walls, trees, infiltration trenches, wetlands, rainwater harvesting and permeable pavements exhibit multi-functionality. They are capable of reducing stormwater runoff, retaining stormwater in the landscape, preserving the natural water balance, enhancing local climate resilience and also delivering ecological, social and community services. Creating multi-functional, multiple-benefit systems, however, also warrants multidisciplinary approaches involving landscape architects, urban planners, engineers and more to successfully create a balance between cities and nature. This Special Issue aims to bridge this multidisciplinary research gap by collecting recent challenges and opportunities from on-site systems up to the watershed scale. Full article