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Publication A comprehensive review of various environmental factors’ roles in remote sensing techniques for assessing surface water quality(Elsevier, 2024-11-23) Diganta, Mir Talas Mahammad; Uddin, Md Galal; Rahman, Azizur; Olbert, Agnieszka I.; Environmental Protection Agency, Ireland; Hardiman Research Scholarship, University of Galway; Science Foundation IrelandThe aim of the research was to evaluate the existing remote sensing (RS) products, various tools and techniques, and their limitations in retrieving the optically active (OA) Chlorophyll-a (CHL) concentration from transitional, coastal and inland waters. In recent decades, satellite RS technique has emerged as a vital tool for assessing surface water quality (WQ) in a cost-effective and timely manner. Initially used in the 1970s to study ocean color (OC), RS techniques have advanced significantly, enabling the retrieval of key WQ indicators like CHL, colored dissolved organic matter (CDOM), total suspended matter (TSM), turbidity (TURB), and more from satellite images. Among these indicators, CHL is particularly important as it directly signifies eutrophication. While RS technique has been reliable in estimating CHL concentrations in open waterbodies (case1 water) such as oceans, it’s application in shallow, turbid waters (case2 water) like coastal and inland areas faces challenges. Interference from other OA-WQ indicators like CDOM and TSM, coupled with environmental factors such as atmospheric components, sun-glint, and adjacency effects (AE), complicate the accurate CHL estimation. To address these challenges, researchers have developed four categories of CHL retrieval algorithms: empirical, semi-empirical, hybrid and data-driven models. Empirical and data-driven methods are straightforward but require regional calibration for accuracy, whereas semi-empirical approaches, rooted in solid theoretical foundations, demand extensive ancillary optical measurements. To harness the potential of RS in WQ assessment fully, it is essential to optimize these algorithms regionally, tailoring them to the specific optical characteristics of diverse waterbodies. This optimization process is vital for integrating RS technique as a complementary data source alongside traditional monitoring approach. By addressing the impact of environmental factors and fine-tuning CHL retrieval methods according to regional nuances, satellite RS technique can significantly enhance the reliability and effectiveness of surface WQ evaluation, thereby contributing to more informed and efficient water resource management strategies. This review emphasizes the impact of these factors, categorizes CHL retrieval algorithms into empirical, semi-empirical, hybrid and data-driven methods and applicability in terms of tools/models’ reliability and challenges for the further advancement of this approaches for monitoring transitional, coastal and inland waters. To optimize the reliability of remotely sensed CHL data, regional configuration(s) of retrieving algorithms is vital. By addressing these challenges and tailoring methods to specific regions, integrating satellite RS into traditional monitoring approaches can significantly enhance surface WQ assessment.Publication Critical state shear strength at concrete-sand-bentonite slurry interfaces: mix proportions and rate effects(ICE Publishing, 2022-12-22) O’Dwyer, Kevin G.; McCabe, Bryan A.; Sheil, Brian B.; Irish Research CouncilThis paper describes direct shear testing of a range of sand-bentonite slurry mixes, identified as a gap in the literature. In the absence of a concrete interface, there was an apparent transition zone from sand-governed strength (bentonite content ≤30%) to clay-governed strength (bentonite content ≥80%), which was linked to the sample void ratio. When a concrete interface was introduced, the critical stress ratio (critical state shear stress normalised by the effective normal stress) was found to change linearly with bentonite slurry content, reflecting an interface sliding failure mechanism. The testing also considered the effect of shearing rates ranging from 0.0025 mm/min to 10 mm/min on interface shear strength. The mixtures containing greater bentonite slurry content displayed a greater decrease in the critical stress ratio with increasing shear rate. Very few studies have explored the influence of the relative sand-clay mix composition on interface shear resistance; these results provide a better understanding of their mechanical behaviour and forms a basis for future research in this area.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 AgencyWetlands 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 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 AgencyOnce 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 (pPublication 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 FundThe 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 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 AgencyPesticides 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.; TeagascIntermittent 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 ValladolidThe 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 SawmillsThis 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, PatrickOn 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, PatrickIn 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 AgencyThe 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 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 GalwayThis 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, EdwardThe 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, IsabelleWorldwide 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.Publication An investigation into the growth of lolium perenne L. and soil properties following soil amendment with phosphorus-saturated bauxite residue(Springer, 2022-04-07) Cusack, Patricia B.; Healy, Mark G.; Callery, Oisín; Di Carlo, Elisa; Ujaczki, Éva; Courtney, RonanIndustrial by-products, such as bauxite residue, may be used to treat phosphorus (P)-enriched water and wastewater. Once fully saturated, they may be reused as P fertilisers. This study aimed to investigate the effectiveness of P-saturated bauxite residue on biomass yield of perennial ryegrass (Lolium perenne L.), identify any adverse effects on soil fauna such as Eisenia fetida L. using choice tests, and quantify any phytotoxic effects on the germination of seeds, root growth, and plant elemental uptake. Two types of spent P-saturated bauxite residue were examined: P-saturated bauxite residue, which had been modified with gypsum at a rate of 8% w/w and chemically amended bauxite residue. There was a comparable biomass yield between the plants grown on the bauxite residue nutrient source and those receiving superphosphate, indicating that there were no phytotoxic effects on the growth of L. perenne L. When examining the effect of the treatments on the soil fauna, the E. fetida L. showed a significant preference in the choice of soil treatment, the largest percentage (58± 2.1 %) of E. fetida L. favoured the control soil over the amended soils. Overall, the bauxite residue was comparable to the superphosphate fertiliser in terms of the biomass yield obtained, indicating the potential recycling of P from wastewaters using bauxite residue as a low-cost adsorbent. No phytotoxic effects on the growth of L. perenne L. were found using germination and plant uptake bioassays.Publication The distribution, type, popularity, size and availability of river-run gravel and crushed stone for use in land drainage systems, and their suitability for mineral soils in Ireland(Compuscript for Teagasc (Agriculture and Food Development Authority, Ireland), 2022-06-24) Byrne, I.; Healy, Mark G.; Fenton, O.; Tuohy, P.The performance of land drainage systems installed in mineral soils in Ireland is highly variable, and is dependent on, amongst other factors, the quality and suitability of the aggregate used. In Ireland, aggregate for land drainage systems is usually river-run gravel and crushed stone. This study classified the distribution, type, popularity, size and availability of aggregates for land drainage systems throughout Ireland and quantified their suitability for use in mineral soils. Eighty-six quarries were surveyed. Limestone and river-run gravel (80% of lithologies) are widespread throughout the country. The quarry aggregate sizes (¿Q sizes¿), reported by the quarries as either a single size i.e. ¿50 mm¿ or a graded size i.e. 20 ¿ 40 mm, were variable, changed across lithology and region, and were, in most cases, larger than what is currently recommended. A particle size distribution analysis of 74 samples from 62 quarries, showed that individual Q sizes increased in variability with increasing aggregate size. In some regions, the aggregate sold does not meet current national regulations, which specify an aggregate size ranging from 10 to 40 mm. The suitability of these aggregates for drainage in five soils of different textures were compared using three established design criteria. It was found that the aggregate in use is too large for heavy soil textures and is therefore unsuitable as drainage envelope material. Guidance for contractors, farmers, and quarry owners will be required, and investment may be needed by quarries to produce aggregate that satisfies design criteria. An aggregate size, based on one or a combination of established aggregate design criteria, where an analysis of the soil texture is conducted and an appropriate aggregate is chosen based off its fifteen percent passing size, is required.Publication A novel hybrid coagulation-intermittent sand filter for the treatment of dairy wastewater(Elsevier, 2022-08-06) Mohamed, A. Y. A.; Siggins, A.; Healy, Mark G.; Fenton, O.; Ó hUallacháin, D.; Tuohy, P.; TeagascAn intermittent sand filter (ISF) is a simple and cost-effective treatment method that may be adopted on farms to treat dairy wastewater (DWW). However, the use of ISFs has been limited due to the large area required for treatment, and the risk of filter clogging and phosphorus (P) breakthrough, which decrease the operational lifetime. To overcome these limitations, this study uses a novel, pilot-scale coagulation-sedimentation process prior to loading ISFs with DWW. The performance and operational lifetime of this new hybrid coagulation-ISF system was compared to a conventional ISF system in a replicated outdoor pilot-scale experiment over a 43-wk study duration (covering an entire milking season on a farm in Ireland). The hybrid system was able to operate effectively at a higher hydraulic loading rate than a conventional ISF system. The effluent quality from the conventional ISF deteriorated over the timeframe of the study until clogging occurred, while the hybrid system continued to perform effectively without any evidence of clogging or P breakthrough. The hybrid system obtained removal efficiencies ≥99% for all measured water quality parameters (chemical oxygen demand, total suspended solids, total P, ammonium and turbidity), and complied with EU directives concerning urban wastewater treatment. Overall, the hybrid coagulation-ISF is a promising technology that requires a small area (75% reduction in footprint in comparison to a conventional ISF) and minimal operator input, and produces high effluent quality.Publication A novel hybrid coagulation-constructed wetland system for the treatment of dairy wastewater(Elsevier, 2022-07-29) Mohamed, A.Y.A.; Siggins, A.; Healy, Mark G.; Ó hUallacháin, D.; Fenton, O.; Tuohy, P.; TeagascConstructed wetlands (CWs) are a cost-effective and sustainable treatment technology that may be used on farms to treat dairy wastewater (DWW). However, CWs require a large area for optimal treatment and have poor long-term phosphorus removal. To overcome these limitations, this study uses a novel, pilot-scale coagulation-sedimentation process prior to loading CWs with DWW. This hybrid system, which was operated on an Irish farm over an entire milking season, performed well at higher hydraulic loading rates than conventional CWs, and obtained removal efficiencies ≥99 % for all measured water quality parameters (chemical oxygen demand, total nitrogen and phosphorus, total suspended solids and turbidity), which complied with EU directives concerning urban wastewater treatment. Overall, the hybrid coagulation-CW is a promising technology that requires a smaller area than conventional CWs and minimal operator input, and produces high effluent quality.