Civil Engineering (Scholarly Articles)

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  • Publication
    An integrated connectivity risk ranking for phosphorus and nitrogen along agricultural open ditches to inform targeted and specific mitigation management
    (Frontiers Media, 2024-02-19) Opoku, D. G.; Healy, Mark G.; Fenton, Owen; Daly, K.; Condon, T.; Tuohy, Patrick; Teagasc
    On dairy farms with poorly drained soils and high rainfall, open ditches receive nutrients from different sources along different pathways which are delivered to surface water. Recently, open ditches were ranked in terms of their hydrologic connectivity phosphorus (P) along the open ditch network. However, the connectivity risk for nitrogen (N) was not considered in that analysis, and remains a knowledge gap. In addition, the P connectivity classification system assumes all source-pathway interactions within open ditches are active, but this may not be the case for N. The objective of the current study, conducted across seven dairy farms, was to create an integrated connectivity risk ranking for P and N simultaneously, to better inform where and which potential mitigation management strategies could be considered. First, a conceptual figure of known N open ditch source-pathway connections, developed using both the literature and observations in the field, was used to identify water grab sampling locations on the farms. During field work, all open ditch networks were digitally mapped, divided into ditch sections, and classified in terms of the existing P connectivity classification system. Sampling was conducted during the hydrologically-active period to ensure maximum connectivity of source-pathways and open ditches. The results from these water samples enabled a qualitative validation of N source-pathway presence or absence for each ditch category. The results showed that not all source-pathways were present across ditch categories for all species of N. This information was used to develop an improved open ditch connectivity classification system. Results showed that farmyard connection ditches were the riskiest for potential point source losses and outlet ditches had the highest connectivity risk among the other ditches associated with diffuse sources. Tailored mitigation options for P and N speciation were identified for these locations to intercept nutrients before reaching receiving waters. Furthermore, in ditches associated with diffuse sources, nitrate was introduced by subsurface sources (i.e., in-field drains and groundwater interactions from springs seepage and upwelling) and ammonium was introduced through surface connectivity pathways (i.e., runoff from internal roadways). In-field drains dominated connectivity pathways in open ditches. On dairy farms where open ditches are prevalent, the integrated classification system and mapping procedure presented herein will enable a targeted and nutrient-specific mitigation plan to be developed.
  • Publication
    Sciomyzidae (Diptera) assemblages in constructed and natural wetlands: implications for constructed wetland design.
    (Springer, 2023-12-08) Mulkeen, Collette J.; Gormally, Michael J.; Swaney, William T.; Healy, Mark G.; Williams, Christopher David; Environmental Protection Agency
    Wetlands constructed primarily for the treatment of wastewaters have been shown to have a role in enhancing biodiversity. However, while most biodiversity studies of constructed wetlands focus on the larger, more iconic animal groups, there is a paucity of information on the aerial phases of wetland invertebrate species associated with constructed wetlands. This study compares Sciomyzidae (Diptera) assemblages, established indicators of wetland dipteran communities, in Irish constructed and natural wetlands, in addition to determining the impacts of water quality and surrounding habitats on Sciomyzidae community structure. Natural wetlands had significantly greater species richness, abundances and diversity (measured as Shannon¿s entropy) of sciomyzid flies than constructed wetlands. Nevertheless, although concentrations of nitrogen and phosphorus in waters were significantly greater in constructed wetlands, seven of the eight constructed wetlands examined hosted species of Sciomyzidae listed as scarce or threatened in Britain. In addition, sciomyzid species richness increased as areas of semi-natural habitat immediately surrounding constructed and natural wetlands increased. Composition of Sciomyzidae assembalges in both natural and constructed wetlands were analysed. The results of this study demonstrate that constructed wetlands can be important contributors to biodiversity particularly in the context of current losses of natural wetlands worldwide. The importance of habitats immediately surrounding constructed wetlands also highlights the need for relatively simple design recommendations (e.g. wet grassland creation or judicious planting of wetland trees) that could enhance the biodiversity of existing and future constructed wetlands.
  • Publication
    Phosphorus fertiliser equivalent value of dairy processing sludge-derived STRUBIAS products using ryegrass (Lolium perenne L.) and spring wheat (Triticum aestivum)
    (Wiley, 2023-12-11) Shi, W.; Fenton, Owen; Ashekuzzaman, S. M.; Daly, K.; Leahy, J. J.; Khalaf, N.; Chojnacka, K.; Numviyimana, C.; Warchoł, J.; Healy, Mark G.; Horizon 2020
    Struvite, biochar and ash products (collectively known as STRUBIAS) products derived from different waste streams are used as fertilisers in agriculture. Raw dairy processing sludge (DPS) shows promise as bio-based fertilisers, but their secondary STRUBIAS-derived products need testing as fertilisers. The objective of this ryegrass (Lolium perenne L.) and wheat (Triticum aestivum) pot trial was to calculate their phosphorus mineral fertiliser equivalency (P-MFE) using the apparent P method for Fe-DPS and DPS-derived struvites (Struvite 1 ¿ 4), hydrochars (HC1 ¿ 3) and ash. Results showed that the products can be divided into two groups: (1) a range of products that can (i.e., Struvite 1 ¿ 3) and (2) cannot (i.e., Struvite 4, HC1 ¿ 3, ash and Fe-DPS) be considered as fertilisers. In the first group, the P-MFE ranged from 66.8 to 76.7% for ryegrass and from 77.9 to 93.5% for spring wheat grain. In the second group, the P-MFE ranged from 7.8 to 58.3% for ryegrass and from -34.5 to -151.3% for spring wheat grain. Processing solutions could overcome problems. These may include the avoidance of Fe dosing salts (in the case of struvite) by using biological methods of P removal or the utilisation of oxalic acid during struvite precipitation, which removes Fe from the process chain and produces higher yields. Future policy and research must be aware that not all STRUBIAS products are suitable as fertilisers and therefore need to be tested individually.
  • Publication
    Field assessment of coconut-based activated carbon systems for the treatment of herbicide contamination
    (Elsevier, 2023-12-03) McGinley, John; Healy, Mark G.; Scannell, Shane; Ryan, Paraic C.; Harmon O'Driscoll, Jenny; Mellander, Per-Erik; Morrison, Liam; Siggins, Alma; Environmental Protection Agency
    Once released into the environment, herbicides can move through soil or surface water to streams and groundwater. Filters containing adsorbent media placed in fields may be an effective solution to herbicide loss in the environment. However, to date, no study has investigated the use of adsorbent materials in intervention systems at field-scale, nor has any study investigated their optimal configuration. Therefore, the aim of this paper was to examine the efficacy of low-cost, coconut-based activated carbon (CAC) intervention systems, placed in streams and tributaries, for herbicide removal. Two configurations of interventions were investigated in two agricultural catchments and one urban area in Ireland: (1) filter bags and (2) filter bags fitted into polyethylene pipes. Herbicide sampling was conducted using Chemcatcher® passive sampling devices in order to identify trends in herbicide exceedances at the sites, and to quantifiably assess, compare, and contrast the efficiency of the two intervention configurations. While the Chemcatcher® passive sampling devices are capable of analysing eighteen different acid herbicides, only six different acid herbicides (2,4-D, clopyralid, fluroxypyr, MCPA, mecoprop and triclopyr) were ever detected within the three catchment areas, which were also the only acid herbicides used therein. The CAC was capable of complete herbicide removal, when the water flow was slow (0.5 ¿ 1 m3.s-1), and the interventions spanned the width and depth of the waterway. Overall, the reduction in herbicide concentrations was better for the filter pipes than for the filter bags, with a 48% reduction in detections and a 37% reduction in exceedances across all the sampling sites for the filter pipe interventions compared to a 13% reduction in the number of detections and a 24% reduction in exceedances across all sampling sites for the filter bag interventions (p
  • Publication
    Experimental investigation of the moment-rotation behaviour of beam-column connections produced using compressed wood connectors
    (Elsevier, 2022-04-04) Mehra, Sameer; O'Ceallaigh, Conan; Sotayo, Adeayo; Guan, Zhongwei; Harte, Annette M.; European Regional Development Fund
    The widespread use of energy-intensive metallic connectors and synthetic adhesives in modern timber construction has negative implications for the end-of-life disposal or re-use of the structural timber components. Therefore, it is favourable to substitute metallic connectors and synthetic adhesives with bio-based alternatives such as wood-based connectors. Recent studies have shown that densified or compressed wood (CW) with superior mechanical properties could be suitable for the manufacture of wood-based connectors in the form of CW dowels and CW plates. This study experimentally examines the moment-rotation behaviour of semi-rigid type timber-CW beam-beam connections under pure bending. The study also assesses the suitability of current design rules to predict the moment capacity of timber-CW connections. The comparative study has shown that the moment capacity of the timber-CW connection can be conservatively predicted from the characteristic load-carrying capacity of the connections calculated using the EC 5 strength equations.
  • Publication
    Life cycle assessment of sitka spruce forest products grown in Ireland
    (Springer, 2023-08-28) Dolan, Desmond; O’Ceallaigh, Conan; Gil-Moreno, David; McGetrick, Patrick J.; Harte, Annette M.
    Purpose The purpose of this study is to quantify the environmental impacts of Sitka spruce timber products harvested from the forestry sector in Ireland. This data is typically country-specific and is required to accurately quantify the environmental impacts associated with its production to better understand the impacts on the environment. Methods A representative model utilising the ReCiPe midpoint approach is developed for the forest sector and the production of log products in Ireland from primary data collected from the national forestry agencies, boardmill and sawmills over a 12-month period, where the last two represent 100% and 67% of the national production volume, respectively. The model was analysed using Life Cycle Assessment (LCA) and the resulting environmental impacts of log production are presented for two different boundary conditions, namely ‘cradle-to-forest road’ and ‘cradle-to-factory gate’ which considers the transport of the logs for further processing. Results and discussion The results are presented for the reference functional unit of 1 m3 of Sitka spruce log product but the results are also shown for 1 rotation of 1 ha of forest area, which allows comparisons with existing studies that utilise similar metrics such as a given area of forest. The results show that typically, clearfell operations are the most significant contributor to all impact categories. The contribution of the remaining operations in descending order of magnitude are thinning operations, forest road construction and maintenance, site preparation options, seedling production and finally forest maintenance operations. The extended model (‘cradle-to-factory gate’ model), which includes transport or delivery, has demonstrated a significant contribution due to transport alone where it was found to be responsible for, on average, 50% of each impact category presented (excluding land occupation) highlighting its significance. Conclusions The underlying Life Cycle Inventory (LCI) data, which quantifies the total outputs of emissions and substances to air, land and water, is presented. It can be seen that the contribution of different operations varies significantly dependent on the log type which provides important data which can be further incorporated into future studies for downstream products utilised in the construction industry.
  • Publication
    The influence of age on the timber properties and grading of Scots pine and larch in Ireland
    (Oxford University Press, 2023-06-13) Gil-Moreno, David; Manso, Rubén; O’Ceallaigh, Conan; Harte, Annette M.; Department of Agriculture, Food and the Marine, Ireland; Higher Education Authority; Department of Further and Higher Education, Research, Innovation and Science
    Scots pine (Pinus sylvestris L.) and larch (Larix spp.) are two species that could contribute to diversifying Ireland’s timber supply. However, there is little knowledge about their properties as well as their variation with age. The aim of this study is to investigate the structural properties (modulus of elasticity, strength and density) of Irish-grown Scots pine and larch and the effect of cambial age on timber grading. Structural-sized pieces were used for this purpose, and the timber properties, knots and ring width were measured on 158 and 250 pieces of Scots pine and larch, respectively. Characteristic values of the properties and indicative yields for different strength classes were calculated. The age effect was assessed using an empirical approach, and a novel modelling approach that disaggregates the timber properties at the annual growth ring level. Yields above 90 per cent of C20 were achieved for Scots pine, whereas larch achieved a 100 per cent yield of C24 strength class. The effect of cambial age in the grading properties indicated that older boards increased the characteristic values of a timber population. In Scots pine, the empirical approach showed that the yields increased by up to 26 per cent when using pieces up to 50 years old compared with pieces up to 30 years old. In larch, the use of pieces up to 40 years old increased the yields by up to 16 per cent compared with using pieces up to 30 years old. The results of the modelling approach were consistent with the values obtained in the empirical analysis and can help to make informed decisions regarding rotation lengths for the production of structural timber. Our results found that cambial ages of 40 years in Scots pine produce high yields of structural timber, whereas 30 years are enough for larch.
  • Publication
    A review on building-integrated photovoltaic/thermal systems for green buildings
    (Elsevier, 2023-04-25) Şirin, Ceylin; Goggins, Jamie; Hajdukiewicz, Magdalena; Science Foundation Ireland; MaREI Centre; Engineering and Physical Sciences Research Council; Horizon 2020; Enterprise Ireland
    Space constraints in urban areas can make it difficult to utilise renewable energy resources, like solar energy systems. However, this limitation can be overcome by utilising building façades to produce energy. Up to 40% of the global energy demand is due to the energy consumed by buildings, which also account for 33% of the global greenhouse gas (GHG) emissions. Buildings have both electrical and thermal energy demand for various processes such as lighting, space heating and hot water supply. The simultaneous production of electrical and thermal energies is possible with photovoltaic thermal (PV/T) systems. Electrical efficiency can be upgraded by decreasing the surface temperatures of the photovoltaic (PV) panels with the working fluid circulating in the system. Building-integrated PV/T (BIPV/T) systems within building façades can successfully produce both electrical and thermal energy and, thus, improve buildings’ energy performance. This review study explains the operation of BIPV/T systems, their classification and utilisation benefits, performance improvement techniques, and potential contributions to energy-efficient buildings. The major goal of this study is to present new users and researchers with access to up-to-date sources of information about BIPV/T systems in the literature. This study includes recent BIPV/T technological advancements published in literature, emphasises the primary goals of the cited works and their hotspots, and, thus, provides readers with an overview of the topic rather than a detailed analysis of BIPV/T systems.
  • Publication
    Phosphorus and nitrogen leaching from an organic and a mineral soil receiving single and split dairy slurry applications: A laboratory column experiment
    (Springer, 2022-11-12) González Jiménez, J. L.; Daly, K.; Healy, Mark G.; Department of Agriculture, Forestry and the Marine
    Purpose Intensification of farming means that organic soils, of low phosphorus (P) holding capacity, are being brought into production. Consequently, farmers may have to adjust their fertiliser application regimes to reduce environmental risk. The aim of this paper is to test the hypothesis that overall loads of P and nitrogen are smaller when applications are split in two compared to a single application. Materials and methods A laboratory column experiment was conducted in which two soils, one organic and one mineral, were exposed to dairy slurry applications of 15, 30 and 55 kg P ha−1 applied in one single application or split into two applications. The columns were uniformly irrigated weekly with 160 mL of distilled water (equivalent to average precipitation in Ireland) and the leached water was analysed for nutrients. Results and discussion There were no significant cumulative P loads in the leached water for any soil type or treatment (minimum and maximum values ranging from 0.04 to 0.12 kg dissolved reactive phosphorus (DRP) ha−1 and 0.09 to 0.14 kg DRP ha−1 for the organic and mineral soil, respectively, and 1.5 to 1.8 kg total phosphorus (TP) ha−1 and 1.8 to 2.9 kg TP ha−1 for the organic and mineral soil, respectively). There was high ammonium-N retention within the organic soil (0.2–0.4 kg ha−1, compared to 15.0–36.8 ha−1 for mineral soils in the leached water). Nitrate–N loads were higher from the organic soil (6.5–105.3 ha−1) than the mineral soil (9.7–17.4 ha−1), although for both soils, loads from the amended columns were lower than the controls (110.7 and 20.1 NO3-N ha−1 for the organic and mineral soil, respectively). Conclusions The overall finding of this study was that split slurry applications had little effect on nutrient exports when compared to single applications, making the amounts of slurry applied, and not the application regime, the predominant factor in nutrient loss.
  • Publication
    Impact of historical legacy pesticides on achieving legislative goals in Europe
    (Elsevier, 2023-02-26) McGinley, J.; Healy, Mark G.; Ryan, P. C.; O'Driscoll, Harmon; Mellander, P. E.; Morrison, L.; Siggins, A.; Environmental Protection Agency
    Pesticides are widely used in agriculture to optimise food production. However, the movement of pesticides into water bodies negatively impacts aquatic environments. The European Union (EU) aims to make food systems fair, healthy and environmentally friendly through its current Farm to Fork strategy. As part of this strategy, the EU plans to reduce the overall use and risk of chemical pesticides by 50% by 2030. The attainment of this target may be compromised by the prevalence of legacy pesticides arising from historical applications to land, which can persist in the environment for several decades. The current EU Farm to Fork policy overlooks the potential challenges of legacy pesticides and requirements for their remediation. In this review, the current knowledge regarding pesticide use in Europe, as well as pathways of pesticide movement to waterways, are investigated. The issues of legacy pesticides, including exceedances, are examined, and existing and emerging methods of pesticide remediation, particularly of legacy pesticides, are discussed. The fact that some legacy pesticides can be detected in water samples, more than twenty-five years after they were prohibited, highlights the need for improved EU strategies and policies aimed at targeting legacy pesticides in order to meet future targets.
  • Publication
    Effects of wastewater pre-treatment on clogging of an intermittent sand filter
    (Elsevier, 2023-03-11) Mohamed, A.Y.A.; Tuohy, P.; Healy, Mark G.; Ó hUallacháin, D.; Fenton, O.; Siggins, A.; Teagasc
    Intermittent sand filters (ISFs) are widely used in rural areas to treat domestic and dilute agricultural wastewater due to their simplicity, efficacy and relative low cost. However, filter clogging reduces their operational lifetime and sustainability. To reduce the potential of filter clogging, this study examined pre-treatment of dairy wastewater (DWW) by coagulation with ferric chloride (FeCl3) prior to treatment in replicated, pilot-scale ISFs and monitored their performance over an entire milking season (301 days). Over the study duration and at the end of the study, the extent of clogging across hybrid coagulation-ISFs was quantified and the results were compared to ISFs treating raw DWW without a coagulation pre-treatment, but otherwise operated under the same conditions. During operation, biomass growth/extent of clogging was higher in ISFs treating raw DWW, which were fully clogged after 280 days of operation. The hybrid coagulation-ISFs remained fully operational until the end of the study. Examination of the filter media in both filter types showed that the ISFs treating raw DWW lost approximately 85% of their initial infiltration capacity in the uppermost layer due to biomass build-up versus 40% loss for hybrid coagulation-ISFs. Furthermore, ISFs treating raw DWW retained more organic matter and proportionally higher amounts of phosphorus, nitrogen and sulphur than the pre-treated DWW, with values decreasing with depth below the filter surface. Overall, hybrid coagulation-ISFs are likely to sustain infiltration capacity for a longer period than filters treating raw wastewater; therefore, requiring smaller surface area for treatment and minimal maintenance.
  • Publication
    Modulus of elasticity prediction through transversal vibration in cantilever beams and ultrasound technique of different wood species
    (Elsevier, 2023-02-21) Acuña, Luis; Martínez, Roberto; Spavento, Eleana; Casado, Milagros; Álvarez-Martínez, Javier; O'Ceallaigh, Conan; Harte, Annette M.; Balmori, Jose-Antonio; Junta de Castilla y León; European Regional Development Fund; Universidad de Valladolid
    The prediction of the modulus of elasticity (MOE) of five species of different spectrum density woods, namely, Populus × euramericana I-214 (Poplar), Fagus sylvatica L. (Beech), Quercus pyrenaica L. (Oak), Paulownia elongata S.Y.Hu (Paulownia) and Pinus sylvestris L. (Scots pine) were examined through the natural frequency of vibration on cantilevered beams (transverse direction) and ultrasound (longitudinal direction). Cantilever beams are commonly used for other materials but limited information is available for wood materials tested in this manner. A total of 60 specimens with nominal dimensions of 40 × 60 × 1200 mm3 were tested, which were visually graded according to UNE 56544:2022 and UNE 56546:2022 as first class, and finally the global bending stiffness was obtained from a four-point bending test. Utilising this data, a regression model was presented to predict the MOE. Also, Picea sitchensis Trautv. & G.Mey (Sitka spruce) has been chosen as a blind species in order to validate the regression model of prediction of the MOE as a function of the dynamic MOE by ultrasound. Bending strength, modulus of elasticity and density were obtained according to the EN 408. In the prediction model using the dynamic MOE with vibrations, an r2 of 95.9% was achieved for the induced vibration technique which was found to be slightly higher than the model for the ultrasound prediction which had an r2 of 93.7%.
  • Publication
    Web geometry optimisation of novel latticed LVL-webbed timber I-joists
    (Elsevier, 2022-12-02) Harte, Annette M.; Baylor, Gordon; O'Ceallaigh, Conan; Enterprise Ireland; Grainger Sawmills
    This paper presents the finite element analysis of novel composite timber I-joists with curved latticed webs. The flanges of the joists were made from Norway Spruce whilst the curved latticed webs were made from laminated veneer lumber (LVL). The I-joists are analysed using the finite element method (FEM) with the component materials modelled as linear elastic orthotropic materials in both tension and compression. Good correlation was found between the experimental test results and the FE simulations when utilising material properties based on experimental investigation. The validated FE model was shown to reasonably predict the load-displacement behaviour and was used to assess the stress distributions within the novel I-joist and particularly in the latticed LVL web. The developed FE model provides a useful tool to further analyse and optimise the design. A geometric parameter study was carried out to enhance the structural performance of the novel I-joists by altering the geometry of the latticed web components and an optimised geometry is presented.
  • Publication
    Assessment of the hydraulic and filter performance of different drainage stone aggregates to elucidate an optimum size range for use in clay-textured soils
    (Elsevier, 2023-01-18) Byrne, Ian; Healy, Mark G.; Fenton, Owen; Tuohy, Patrick
    On poorly drained grassland farms in Ireland, stone aggregates remain the only in-field drain envelope material used by contractors. A variety of aggregate sizes and lithologies are currently in use, but their performance in clay-textured mineral soils is unknown. In practice, this may result in ad-hoc system performance and a varied lifespan due to sediment ingress. The aim of this study was to evaluate the hydraulic and filter performance of a range of aggregate gradations in clay-textured mineral soils. Nine aggregates (three replicates of each) were examined in laboratory units containing clay-textured soil, with a perforated drainpipe surrounded by an aggregate envelope ranging in size from 0.7 to 62 mm and a constant 0.4 m head of water above the soil surface. To determine the hydraulic performance of the envelope, the discharge rate of water through the drainage pipe outlet was measured over 38 days. To determine the filter performance, sediment loss, sediment settlement in the drainpipe, and ingress of sediment into the envelope were measured. The results indicated that only aggregates in the 0.7 to 19 mm size range performed adequately from both the hydraulic and filter perspectives and were deemed suitable for use with a clay-textured soil. Discharge appeared to be inversely related to aggregate size, with larger discharges being measured in the smaller aggregate sizes and smaller discharges measured in the larger aggregate sizes (exception: Aggregate 2). For all aggregates examined, discharge was greatest at the start of the experiment before reducing over time. When the cost of the aggregate material is also considered, aggregates in the lower size range are 18 to 50% more expensive than aggregates in the higher size range. Aggregates with particle sizes ranging from 0.7 to 19 mm are recommended for in-situ field testing in clay-textured soils.
  • Publication
    Investigating the suitability of synthetic envelopes as an alternative or complement to stone aggregate in clay-textured soils in Ireland
    (Elsevier, 2022-12-21) Byrne, Ian; Healy, Mark G.; Fenton, Owen; Tuohy, Patrick
    In Ireland, agricultural landscapes dominated by high rainfall and poorly drained soils have high densities of in-field pipe drains surrounded by stone aggregate envelopes. Unlike other countries, there is limited availability and use of synthetic envelopes, and no data exist about their suitability and efficacy in clay-textured soils. Indeed, both aggregate and synthetic envelope- based designs have been implemented without knowledge of their suitability or efficacy. Available synthetic envelopes have two configurations: pre-wrapped loose materials and pre-wrapped geotextiles (woven, non-woven, and knitted, with the knitted being the most common in the U.S. and Canada). In total, five configurations (referred to in this paper as `treatments¿) were examined in this study with a view to ranking them from performance and cost perspectives. The treatments were: a 0.8 mm thick needle-punched, non-woven geotextile or a 2 mm thick knitted filter sock wrapped around the drainpipe, with no aggregate (Treatments 1 and 2, respectively); a 0.8 mm-thick needle-punched, non-woven geotextile wrapped around 2 ¿ 10 mm (dD10 ¿ dD90) stone aggregate (Treatment 3); a 2 mm thick knitted filter sock wrapped around a drainpipe surrounded by 2-10 mm stone aggregate (0.15 m above pipe, 0.13 m below pipe) (Treatment 4); and a 2-10 mm stone aggregate alone (0.15 m above pipe, 0.13 m below pipe) (Treatment 5). The hydraulic and filter performance of Treatments 1 to 4 were compared with Treatment 5. Treatments 3 and 4 were assessed to determine if they improved hydraulic conductivity and filter performance over Treatment 5. Using cumulative discharge and cumulative flow weighted sediment loss (total suspended solids: TSS) as indicators of performance, geotextiles performed poorly from discharge and TSS perspectives. The discharge for Treatment 1 and Treatment 2 was below the discharge observed from the stone aggregate, and cumulative TSS losses were 636% and 709% higher (Treatment 1 and 2, respectively). The discharge from Treatments 3 and 4 was 67% and 134% higher than the stone aggregate, but this produced an increase in cumulative sediment losses. Treatment 5 performed effectively, with a discharge that was higher than that observed in the geotextile treatments (Treatments 1 and 2) but lower than that observed in Treatments 3 and 4. The use of these treatments, either alone or in combination with stone aggregate, is not recommended in the clay-textured soil tested, from both performance and cost perspectives. Therefore, this study recommends that stone aggregates in the optimal size range should be used as drain envelope material in similar textured soils in Ireland.
  • Publication
    The impact of alternating drainage and inundation cycles on geochemistry and microbiology of intact peat cores
    (Elsevier, 2022-11-02) Healy, Mark G.; Siggins, Alma; Potito, Aaron P.; Molloy, Karen; Potito, Aaron P.; O'Leary, D.; Daly, E.; Callery, O.; European Commission; Environmental Protection Agency
    The rewetting of degraded peatlands has been adopted as a method to address climate change. Concerns have been raised about the effects of peat inundation and drying cycles, in more extreme climate events, on the potential release of nitrogen (N) species, in particular ammonium (NH4-N), once rewetted, as well as the physico-chemical and biological properties of the peat. This study used intact peat cores to measure the impact of two different cycles of peat inundation and drying (1 month and 2 month) over a total study duration of 56 weeks on the (1) NH4-N, nitrate-N (NO3-N) and dissolved reactive phosphorus (DRP) in the soil pore water; (2) microbial community structure; (3) physico-chemical properties of the peat; and (4) the structure of the peat, and therefore its ability to mitigate flood risks and storm surges. The study found that rewetted cores released NO3-N in the pore water up to a concentration of 6.25 mg L-1, but had no appreciable impact on NH4-N, which remained below 1.7 mg L-1 over the study duration. DRP moved quickly though the upper layers of the cores, but physico-chemical analysis suggested it was adsorbed to more iron-rich soil, which was present at depths below 0.4 m in the cores. Time intervals between inundation produced no significant difference on the forms of inorganic N released, nor did it compact the soil or change the microbial community structure. The depth of the water table, however, had a significant impact on inorganic N release, particularly NO3-N, which indicates that this N species, and not NH4-N, may be problematic in rewetted peatlands.
  • Publication
    Mineral fertiliser equivalent value of dairy processing sludge and derived biochar using ryegrass (Lolium perenne L.) and spring wheat (Triticum aestivum)
    (Elsevier, 2022-08-20) Shi, W.; Healy, Mark G.; Ashekuzzaman, S. M.; Daly, K.; Fenton, Owen; Horizon 2020
    As supply chains of chemical fertilisers become more precarious, raw or derived bio-based fertilisers (herein referred to as bio-fertilisers) from the dairy processing industry could be good alternatives. However, their agronomic performance is relatively unknown, and where documented, the method to estimate this value is rarely presented. This pot study investigated aluminium-precipitated and calcium-precipitated dairy processing sludges (Al and Ca-DPS) and DPS-derived biochar as potential bio-fertilisers to grow ryegrass (Lolium perenne L.) and spring wheat (Triticum aestivum). The study aims were to examine how (1) application rate (optimal versus high) and (2) calculation methods (with and without chemical fertiliser response curves) can affect estimates of nitrogen and phosphorus mineral fertiliser equivalence value (N- and P-MFE) and associated agronomic advice. The results from both crops showed that for nitrogen application rates (125 or 160 kg ha-1 for ryegrass and 160 or 240 kg ha-1 for spring wheat) estimates of N-MFE increased for both Al-DPS and Ca-DPS as application rate increased. Dry matter yield response curves produced highest the % N-MFE results (e.g., ryegrass ~50% and 70% for Al-DPS and Ca-DPS) with other calculation methods producing all similar results (e.g., ryegrass ~20% for Al-DPS and Ca-DPS). For phosphorus application rates (40 or 80 kg ha-1 for ryegrass and 50 or 80 kg ha-1 for spring wheat), estimates of P-MFE did not increase with application rate. Negative P-MFE values obtained for Ca-DPS and DPS-biochar when growing ryegrass and spring wheat grain, respectively, indicated low plant available phosphorus. Overall, Al-DPS had better performance as a bio-fertiliser when compared to the other products tested. There was no significant difference between the two calculation methods of MFE, which suggests that the determination of MFE could be simplified by using one application as opposed to numerous application rates of fertilisers. Future work should focus on elucidating the N- and P-MFE of a wider range of DPS and STRUBIAS bio-fertilisers, and alternative methods should be investigated that enable a comparison across all bio-fertiliser types.
  • Publication
    A computational toolchain for the automatic generation of multiple Reduced-Order Models from CFD simulations
    (Elsevier, 2019-05-25) Marzullo, Thibault; Keane, Marcus M.; Geron, Marco; Monaghan, Rory F. D.; College of Science and Engineering, National University of Ireland Galway
    This paper describes the development of a systematic tool chain capable of automatically extracting accurate and efficient Reduced-Order Models (ROMs) from Computational Fluid Dynamics (CFD) simulations. These ROMs can then be used to support the design and operation of Near-Zero Energy Buildings (NZEB), with a higher accuracy than traditional zonal models but at a fraction of the computational cost of CFD. This study assesses the accuracy and time to solution of these ROMs when solved for appropriate Boundary Conditions (BCs), found in the built environment, in order to define the usability envelope of the automatically extracted ROMs. The parameters used in this study are inlet temperatures (K) and mass flow rates (kg/s). Results demonstrate that the absolute error can be maintained at under 0.5 K for changes in temperature of up to ±15 K, and under 0.25 K for changes in mass flow rates of up to ±45% of the original value. The results show that this method has the potential for applications in the built environment where the ROM accuracy and low computational cost can bridge a gap between low order RC models and high order CFD, further improving the energy efficiency in smart buildings.
  • Publication
    Building performance optimization using cross-domain scenario modeling, linked data, and complex event processing
    (Elsevier, 2013-01-28) O’Donnell, James; Corry, Edward; Hasan, Souleiman; Keane, Marcus M.; Curry, Edward
    The scenario modeling method empowers building managers by enabling comprehensive performance analysis in commercial buildings, but is currently limited to data from the building management domain. This paper proposes that Linked Data and Complex Event Processing can form the basis of an interoperability approach that would help to overcome technical and conceptual barriers to cross-domain scenario modeling. In doing so, this paper illustrates the cross-domain potential of scenario modeling to leverage data from different information silos within organizations and demonstrates how to optimize the role of a building manager in the context of his or her organization. Widespread implementations of cross-domain scenario models require a solution that efficiently manages cross-domain data acquisition and post processing underpinned by the principles of linked data combined with complex event processing. An example implementation highlights the benefits of this new approach. Cross-domain scenario models enhance the role of the building manager within an organization and increase the importance of information communicated by building managers to other organizational stakeholders. In addition, new information presented to stakeholders such as facilities managers and financial controllers can help to identify areas of inefficiency while still maintaining building function and optimized energy consumption. Two key challenges to implementing cross-domain scenario modeling are: the data integration of the different domains' sources, and the need to process scenarios in real-time. This paper presents an implementation approach based on linked data to overcome interoperability issues, and Complex Event Processing to handle real-time scenarios.
  • Publication
    Systematic review of dairy processing sludge and secondary STRUBIAS products used in agriculture
    (Frontiers Media, 2021-11-10) Hu, Yihuai; Khomenko, Olha; Shi, Wenxuan; Velasco-Sánchez, Ángel; Ashekuzzaman, S. M.; Bennegadi-Laurent, Nadia; Daly, Karen; Fenton, Owen; Healy, Mark G.; Leahy, J. J.; Sørensen, Peter; Sommer, Sven G.; Taghizadeh-Toosi, Arezoo; Trinsoutrot-Gattin, Isabelle
    Worldwide dairy processing plants produce high volumes of dairy processing sludge (DPS), which can be converted into secondary derivatives such as struvite, biochar and ash (collectively termed STRUBIAS). All of these products have high fertilizer equivalent values (FEV) but future certification as P-fertilizers in the European Union will mean they need to adhere to new technical regulations for fertilising materials i.e. content limits pertaining to heavy metals (Cd, Cu, Hg, Ni, Pb and Zn) and individual European countries have set limits for synthetic organic compounds and pathogens. This review presents our current state of knowledge pertaining to these bio-based fertilizers and identifies knowledge gaps. In addition a review and calculation of greenhouse gas emission (GHG) from a range of concept dairy sludge management, production and management systems for STRUBIAS products (i.e. biochar from pyrolysis and hydrochar from hydrothermal carbonification (HTC)) were examined. Results from the initial review showed that DPS contents depend on product type and treatment processes at a given processing plant, which leads to varied nutrient, heavy metal and carbon profiles. These products are all typically high in nutrients and carbon but low in heavy metals. Further work needs to concentrate on examining their pathogenic microorganism and emerging contaminant profiles. Specifically with respect to STRUBIAS products contaminants not present in the raw DPS may need further treatment before being land applied in agriculture e.g. heated producing ashes, hydrochar or biochar. An examination of these products from an environmental perspective shows that their water quality footprint could be minimised using application rates based on phosphorus (P), incorporation of these products into nutrient management planning and application using incorporation into the soil. Results from the concept system work showed that elimination of methane emissions was possible along with a reduction in nitrous oxide (N2O). Less carbon is transferred to agricultural fields where DPS is processed into biochar and hydrochar, but due to high recalcitrance the C in this form is retained much longer in the soil, and therefore STRUBIAS products represents a more stable and long term option to increase soil C stocks and sequestration.