Microbiological characterisation and impact of suspended solids on pathogen removal from wastewaters in dairy processing factories.

In this Research Communication we investigate the microbiological profile of 12 dairy wastewater streams from three contrasting Irish dairy processing factories to determine whether faecal indicators/pathogens were present and in turn, whether disinfection may be required for potential water reuse within the factory. Subsequently, the impact of suspended solids on the inactivation efficiency of Escherichia coli via two means of ultravoilet (UV) disinfection; flow-through pulsed UV (PUV) and continuous low pressure UV (LPUV) disinfection was analysed. Faecal indicators total coliforms and E. coli were detected in 10 out of the 12 samples collected at the dairy processing factories while pathogenic bacteria Listeria monocytogenes was detected in all samples collected at 2 out of the 3 factories. Salmonella spp. was undetected in all samples. The results also indicated that organic dairy wastewater solids had an impact on the performance efficiency of the PUV system and, to a lesser extent, the LPUV system. The findings indicate that the targeting of key pathogens would be required to enable wastewater reuse (and indeed effluent discharges if regulation continues to become more stringent) and that LPUV may offer a more robust disinfection method as it appears to be less susceptible to the presence of suspended solids.

DairyWater: striving for sustainability within the dairy processing industry in the Republic of Ireland.

This Review describes the objectives and methodology of the DairyWater project as it aims to aid the Irish dairy processing industry in achieving sustainability as it expands. With the abolition of European milk quotas in March 2015, the Republic of Ireland saw a surge in milk production. The DairyWater project was established in anticipation of this expansion of the Irish dairy sector in order to develop innovative solutions for the efficient management of water consumption, wastewater treatment and the resulting energy use within the country's dairy processing industry. Therefore, the project can be divided into three main thematic areas: dairy wastewater treatment technologies and microbial analysis, water re-use and rainwater harvesting and environmental assessment. In order to ensure the project remains as relevant as possible to the industry, a project advisory board containing key industry stakeholders has been established. To date, a number of large scale studies, using data obtained directly from the Irish dairy industry, have been performed. Additionally, pilot-scale wastewater treatment (intermittently aerated sequencing batch reactor) and tertiary treatment (flow-through pulsed ultraviolet system) technologies have been demonstrated within the project. Further details on selected aspects of the project are discussed in greater detail in the subsequent cluster of research communications.

A novel image processing-based system for turbidity measurement in domestic and industrial wastewater.

Wastewater treatment facilities are continually challenged to meet both environmental regulations and reduce running costs (particularly energy and staffing costs). Improving the efficiency of operational monitoring at wastewater treatment plants (WWTPs) requires the development and implementation of appropriate performance metrics; particularly those that are easily measured, strongly correlate to WWTP performance, and can be easily automated, with a minimal amount of maintenance or intervention by human operators. Turbidity is the measure of the relative clarity of a fluid. It is an expression of the optical property that causes light to be scattered and absorbed by fine particles in suspension (rather than transmitted with no change in direction or flux level through a fluid sample). In wastewater treatment, turbidity is often used as an indicator of effluent quality, rather than an absolute performance metric, although correlations have been found between turbidity and suspended solids. Existing laboratory-based methods to measure turbidity for WWTPs, while relatively simple, require human intervention and are labour intensive. Automated systems for on-site measuring of wastewater effluent turbidity are not commonly used, while those present are largely based on submerged sensors that require regular cleaning and calibration due to fouling from particulate matter in fluids. This paper presents a novel, automated system for estimating fluid turbidity. Effluent samples are imaged such that the light absorption characteristic is highlighted as a function of fluid depth, and computer vision processing techniques are used to quantify this characteristic. Results from the proposed system were compared with results from established laboratory-based methods and were found to be comparable. Tests were conducted using both synthetic dairy wastewater and effluent from multiple WWTPs, both municipal and industrial. This system has an advantage over current methods as it provides a multipoint analysis that can be easily repeated for large volumes of wastewater effluent. Although the system was specifically designed and tested for wastewater treatment applications, it could have applications such as in drinking water treatment, and in other areas where fluid turbidity is an important measurement.

Using image processing for determination of settled sludge volume.

Determination of the sludge volume index is key to describing the settling characteristics of sludge in the aeration process of wastewater treatment plants (WWTPs). The two core components of this calculation are the settled sludge volume (SSV) and suspended solids. While the measurement procedure for SSV is generally defined by national or international standards, in practice a wide variety of vessel sizes and shapes are used by operators to monitor WWTP performance. Furthermore, differences in how these tests are carried out can lead to poor data, inefficient WWTP operation and a lack of comparable metrics for WWTP operational monitoring. Thus, there is a requirement to improve operational performance of WWTPs to meet the increasingly stringent legislation regarding discharge limits. The aim of this study was to utilise a novel image-processing system (AutoSSV) to (i) determine its efficacy in describing SSV and (ii) measure and compare different methodologies for measurement of SSV. The AutoSSV system was tested using samples from various WWTPs and the results compared to those determined by standard manual measurement. Both standard and modified settlement tests were conducted on 30 mixed liquor samples, with modified settlement tests consistently resulting in lower SSV measurements. Results from the study showed a strong correlation between the SSV measurements provided by the AutoSSV system and results obtained from current manual measurement methods. The proposed technique would help to standardise the measurement in practice and increase the frequency of monitoring, particularly in small-scale rural WWTPs where there may not be permanent operators on site, and thus provide sufficient performance monitoring for efficient and effective operation.

Ammonia oxidizing bacteria and archaea in horizontal flow biofilm reactors treating ammonia-contaminated air at 10 °C.

The objective of this study was to demonstrate the feasibility of novel, Horizontal Flow Biofilm Reactor (HFBR) technology for the treatment of ammonia (NH3)-contaminated airstreams. Three laboratory-scale HFBRs were used for remediation of an NH3-containing airstream at 10 °C during a 90-d trial to test the efficacy of low-temperature treatment. Average ammonia removal efficiencies of 99.7 % were achieved at maximum loading rates of 4.8 g NH3 m(3) h(-1). Biological nitrification of ammonia to nitrite (NO2 (-)) and nitrate (NO3 (-)) was mediated by nitrifying bacterial and archaeal biofilm populations. Ammonia-oxidising bacteria (AOB) were significantly more abundant than ammonia-oxidising archaea (AOA) vertically at each of seven sampling zones along the vertical HFBRs. Nitrosomonas and Nitrosospira, were the two most dominant bacterial genera detected in the HFBRs, while an uncultured archaeal clone dominated the AOA community. The bacterial community composition across the three HFBRs was highly conserved, although variations occurred between HFBR zones and were driven by physicochemical variables. The study demonstrates the feasibility of HFBRs for the treatment of ammonia-contaminated airstreams at low temperatures; identifies key nitrifying microorganisms driving the removal process; and provides insights for process optimisation and control. The findings are significant for industrial applications of gas oxidation technology in temperate climates.

Performance and surface clogging in intermittently loaded and slow sand filters containing novel media.

Slow sand filers are commonly used in water purification processes. However, with the emergence of new contaminants and concern over removing precursors to disinfection by-products, as well as traditional contaminants, there has recently been a focus on technology improvements to result in more effective and targeted filtration systems. The use of new media has attracted attention in terms of contaminant removal, but there have been limited investigations on the key issue of clogging. The filters constructed for this study contained stratified layers comprising combinations of Bayer residue, zeolite, fly ash, granular activated carbon, or sand, dosed with a variety of contaminants (total organic carbon (TOC), aluminium (Al), ammonium (NH4(+)-N), nitrate (NO3(-)-N) and turbidity). Their performance and clogging mechanisms were compared to sand filters, which were also operated under two different loading regimes (continuous and intermittently loaded). The study showed that the novel filter configurations achieved up to 97% Al removal, 71% TOC removal, and 88% NH4(+)-N removal in the best-performing configuration, although they were not as effective as sand in terms of permeability. Deconstruction of the filters revealed that the main clogging mechanism was organic matter build-up at the uppermost layer of the filters. The clogging layer formed more quickly on the surface of the novel media when compared to the sand filters, but extended further into the sand filters, the extent dependent on the loading regime. The study shows the potential for an alternative filtration configuration, harnessing the adsorption potential of industrial waste products and natural media.

An evaluation of the performance and optimization of a new wastewater treatment technology: the air suction flow-biofilm reactor.

In this laboratory study, a novel wastewater treatment technology, the air suction flow-biofilm reactor (ASF-BR) - a sequencing batch biofilm reactor technology with a passive aeration mechanism - was investigated for its efficiency in removing organic carbon, nitrogen and phosphorus, from high-strength synthetic wastewaters. A laboratory-scale ASF-BR comprising 2 reactors, 350 mm in diameter and 450 mm in height, was investigated over 2 studies (Studies 1 and 2) for a total of 430 days. Study 1 lasted a total of 166 days and involved a 9-step sequence alternating between aeration, anoxic treatment and settlement. The cycle time was 12.1 h and the reactors were operated at a substrate loading rate of 3.60 g filtered chemical oxygen demand (CODf)/m2 media/d, 0.28 g filtered total nitrogen (TNf)/m2 media/d, 0.24 g ammonium-nitrogen (NH4-N)/m2 media/d and 0.07 g ortho-phosphate (PO4-P)/m2 media/d. The average removal rates achieved during Study 1 were 98% CODf, 88% TNf, 97% NH4-N and 35% PO4-P. During Study 2 (264 days), the unit was operated at a loading rate of 2.49 g CODf/m2 media/d, 0.24 g TNf/m2 media/d, 0.20 g NH4-N/m2 media/d and 0.06 PO4-P/m2 media/d. The energy requirement during this study was reduced by modifying the treatment cycle in include fewer pumping cycles. Removal rates in Study 2 averaged 97% CODf, 86% TNf, 99% NH4-N and 76% PO4-P. The excess sludge production of the system was evaluated and detailed analyses of the treatment cycles were carried out. Biomass yields were estimated at 0.09 g SS/g CODf, removed and 0.21 g SS/g CODf, removed for Studies 1 and 2, respectively. Gene analysis showed that the use of a partial vacuum did not affect the growth of ammonia-oxidizing bacteria. The results indicate that the ASF-BR and passive aeration technologies can offer efficient alternatives to existing technologies.

Comprehensive analysis and assessment of exposure to enteric viruses and bacteria in shellfish.

Shellfish species, including oysters, clams, and mussels, are extensively cultured in coastal waters. Its location is determined by factors such as nutrient availability, water temperature, tidal cycle, and the presence of contaminants such as Escherichia coli and enteric viruses. With the expansion and intensification of human activities at vicinities, the presence of anthropogenic contaminants has increased, threatening shellfish farms and consumer safety give the prevalent consumption of raw shellfish. This literature review aims to provide a comprehensive analysis of the dietary exposure and assess the risk associated with enteric viruses and bacteria detected in shellfish. The predominant bacteria and viruses detected in shellfish are reported, and the potential interrelation is discussed. The main characteristics of each contaminant and shellfish were reviewed for a more comprehensive understanding. To facilitate a direct estimation of exposure, the estimated daily intake (EDI) of bacteria was calculated based on the average levels of E. coli in shellfish, as reported in the literature. The mean daily ingestion of seafood in each of the five continents was considered. Asia exhibited the highest intake of contaminants, with an average of ±5.6 E. coli units/day.kg body weight in cockles. Simulations were conducted using recommended shellfish consumption levels established by state agencies, revealing significantly lower (p < 0.01) EDI for all continents compared to estimations based on recommended levels. This indicates a higher risk associated with healthy shellfish ingestion, potentially leading to increased intoxication incidents with a change in dietary habits. To promote a healthier lifestyle through increased shellfish consumptions, it is imperative to reduce the exposure of shellfish species to bacteria and enteric viruses. The conventional use of E. coli as the sole indicator for consumption safety and water quality in shellfish farms has been deemed insufficient. Instances where shellfish met E. coli limits established by state agencies were often found to be contaminated with human enteric viruses. Therefore, a holistic approach considering the entire production chain is necessary to support the shellfish industry and ensure food safety.

Pulsed ultraviolet (PUV) disinfection of artificially contaminated seawater seeded with high levels of pathogen disease indicators as an alternative for the shellfish industry depuration systems.

The increase in pathogen levels in seawater threatens the safety of entire aquatic ecosystems. Foodborne pathogens can potentially accumulate in shellfish, especially in filter feeders such as bivalves, requiring an efficient depuration process before consumption. Alternative approaches to promote a cost-efficient purge at depuration plants are urgently needed. A small prototype pulsed ultraviolet (PUV) light recirculation system was designed, and its depuration potential was tested in a seawater matrix artificially contaminated with high levels of microbial pathogens Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Bacillus cereus and Candida albicans. The analysis of treatment parameters including voltage, number of pulses and duration of treatment was performed to ensure the highest reduction in contaminant levels. Optimal PUV disinfection was attained at 60 pulses/min at 1 kV for 10 min (a UV output of 12.9 J/cm2). All reductions were statistically significant, and the greatest was observed for S. aureus (5.63 log10), followed by C. albicans (5.15 log10), S. typhimurium (5 log10), B. cereus (4.59 log10) and E. coli (4.55 log10). PUV treatment disrupted the pathogen DNA with the result that S. aureus, C. albicans and S. typhimurium were not detectable by PCR. Regulations were reviewed to address the applicability of PUV treatment as a promising alternative to assist in the reduction of microbial pathogens at depuration plants due to its high efficiency, short treatment period, high UV dose and recirculation system as currently employed in shellfish depuration plants.

Seafood consumers engagement in reducing environmental impacts from packaging.

Packaging is essential to protect food, inform consumers, and avoid food waste, yet it can also contribute to the environmental footprint of products. Recycling waste treatment potentially provides more environmental benefits than other options (e.g., landfill), but only 66 % of packaging waste goes to recycling in the European Union. However, the prevention of packaging production with greater reuse, while extending the lifetime or improving packaging design should be firstly encouraged. This highlights the need to assess the willingness of consumers in reducing the environmental impact of seafood products from packaging. An online questionnaire was conducted in three countries (Portugal, Spain, and Ireland), composed of four sections: (i) seafood consumption, (ii) waste separation to be sent recycling, (iii) willingness to purchase seafood products with packaging designed to reduce environmental impact, and (iv) sociodemographic characteristics. Findings revealed that respondents from Spain and Portugal reported a slightly higher frequency of waste sent to recycle compared to Ireland. Irish respondents appear to have more difficulties about the type of plastic materials that can be sent to recycling due to Irish waste management capabilities; whereas Spanish and Portuguese respondents were not fully aware that packaging does not need to be washed prior to recycling. The most popular alternatives to improve the sustainability of seafood packaging were the use of reusable packaging, compostable packaging material, glass jars for canned seafood instead of cans, and intelligent packaging. Most respondents were willing to pay more for seafood products that use more sustainable packaging (62 % for Spain, 68 % for Ireland, 70 % for Portugal) and half of the respondents intimated that they avoid seafood products due to excessive packaging. With more detailed information on the waste management of packaging, seafood consumers could actively contribute with their attitudes where commensurate changes can improve environmental assessment of seafood.

A systemic framework of energy efficiency in schools: experiences from six European countries.

Schools are complex physical and social institutions within national education systems. They account for significant energy consumption and like other buildings can demonstrate inefficient patterns of energy use. Poor energy performance of educational facilities is an intricate issue driven by complex causality of interconnected and dynamic factors. Addressing this issue requires a systemic approach, which is heretofore lacking. The aim of this research is to present and describe a systemic framework to facilitate energy reduction in schools across different European contexts. This transdisciplinary approach to sustainable energy use has been piloted in 13 post-primary schools located in six countries in northwest Europe. The research implements a series of planned activities and interventions, which help to unveil a systemic approach to improving energy efficiency in schools. The findings demonstrate how this approach, together with its ensuing methodologies and strategies, can contribute to reducing carbon emissions and improve knowledge and awareness around sustainable energy.

Performance of a woodchip filter to treat dairy soiled water.

The milking process on dairy farms produces wastewaters, known as dairy soiled waters (DSW), which contain variable concentrations of nutrients. The most common method of disposal is by application to land. However, this practise can result in the pollution of nearby receiving water bodies. A laboratory study, comprising two sets of 0.5 m, 1 m and 1.5 m-deep filters loaded at two loading rates, examined the performance of woodchip filters in treating DSW. The filters comprised de-barked Sitka spruce (Picea sitchensis) woodchips. Dried DSW was reconstituted to 1% and 3% suspended solids (SS) concentrations and was applied at 28 L/m(2).d to the surface of the filters at loading rates of 280 g SS/m(2).d and 840 g SS/m(2).d, respectively. Filters were loaded for a maximum of 277 days. The filters achieved substantial decreases in SS (>99%), chemical oxygen demand (COD) (>97%) and total nitrogen (TN) (>89%). The dominant treatment mechanism appears to be physical filtration, but sorption and biological uptake likely also play a role. As the filters are aerobic, mineralisation and nitrification occur, but gaseous N losses are probably not significant. Woodchip shows potential as a filter medium for treating DSW, significantly decreasing the concentrations of SS, COD and TN.

Optimization of operational conditions and performances of pilot scale lumbrifiltration for real raw municipal wastewater treatment.

Lumbrifiltration (LF) has been promoted as a low-cost, low maintenance and efficient solution for domestic and municipal wastewater treatment especially. However, there have been limited studies investigating the optimal operating conditions and long-term performances of LF systems (especially in temperate climates). The key objectives of this study were to (i) to present an outcome of the operating conditions and associated performance of LF the systems studied in the literature regarding removal efficiencies for nutrients and organic matter (OM) in municipal and domestic wastewater (WW) treatment contexts, (ii) to generate long term and reliable results on the potential performances of LF systems for the treatment of real municipal WW (for both OM and nutrients), (iii) to optimize operational conditions such as active layer height, earthworms density, HLR and earthworms type, conditions for which it is still unclear from the current literature which are optimal, and (iv) to assess the performances of the LF in a "temperate climate" context. Overall, LF systems showed high removal efficiencies for organic matter and nutrients for all the operating conditions tested. The study also confirmed the positive impact of earthworms in achieving high level of nitrification of ammonium after a short start-up period. The system operation and performances were maintained without maintenance for the whole duration of the study (over 250 days), showing the potential for keeping high level of performances for long-term periods. Recommendations are given in relation to LF system design such as optimal active layer height and hydraulic loading rate. The study also demonstrated the applicability and potential of Dendrobaena veneta as an alternative to Eisenia fetida (the latter generally being used in previous studies but are less available in some areas of Europe) for application in municipal wastewater treatment by LF.

Implications for the seafood industry, consumers and the environment arising from contamination of shellfish with pharmaceuticals, plastics and potentially toxic elements: A case study from Irish waters with a global orientation.

Shellfish are a rich source of minerals, B-vitamins and omega-3 to the human diet. The global population is expected to reach 9.6 billion people by 2050 where there will be increased demand for shellfish and for sustained improvements in harvesting. The production of most consumed species of shellfish is sea-based and are thus susceptible to in situ environmental conditions and water quality. Population growth has contributed to expansion of urbanization and the generation of effluent and waste that reaches aquatic environments, potentially contaminating seafood by exposure to non-treated effluents or inappropriately discarded waste. Environmental contaminants as microplastics (MP), pharmaceuticals (PHAR) and potentially toxic contaminants (PTE) are being identified in all trophic levels and are a current threat to both shellfish and consumer safety. Immunotoxicity, genotoxicity, fertility reduction, mortality and bioaccumulation of PTE are representative examples of the variety of effects already established in contaminated shellfish. In humans, the consumption of contaminated shellfish can lead to neurological and developmental effects, reproductive and gastrointestinal disorders and in extreme cases, death. This timely review provides insights into the presence of MP, PHAR and PTE in shellfish, and estimate the daily intake and hazard quotient for consumption behaviours. Alternatives approaches for seafood depuration that encompass risk reduction are addressed, to reflect state of the art knowledge from a Republic of Ireland perspective. Review of best-published literature revealed that MP, PHAR and PTE contaminants were detected in commercialised species of shellfish, such as Crassostrea and Mytilus. The ability to accumulate these contaminants by shellfish due to feeding characteristics is attested by extensive in vitro studies. However, there is lack of knowledge surrounding the distribution of these contaminants in the aquatic environment their interactions with humans. Preventive approaches including risk assessment are necessary to safeguard the shellfish industry and the consumer.

Digital transformation of peatland eco-innovations ('Paludiculture'): Enabling a paradigm shift towards the real-time sustainable production of 'green-friendly' products and services.

The world is heading in the wrong direction on carbon emissions where we are not on track to limit global warming to 1.5 °C; Ireland is among the countries where overall emissions have continued to rise. The development of wettable peatland products and services (termed 'Paludiculture') present significant opportunities for enabling a transition away from peat-harvesting (fossil fuels) to developing 'green' eco-innovations. However, this must be balanced with sustainable carbon sequestration and environmental protection. This complex transition from 'brown to green' must be met in real time by enabling digital technologies across the full value chain. This will potentially necessitate creation of new green-business models with the potential to support disruptive innovation. This timely paper describes digital transformation of paludiculture-based eco-innovation that will potentially lead to a paradigm shift towards using smart digital technologies to address efficiency of products and services along with future-proofing for climate change. Digital transform of paludiculture also aligns with the 'Industry 5.0 - a human-centric solution'. However, companies supporting peatland innovation may lack necessary standards, data-sharing or capabilities that can also affect viable business model propositions that can jeopardize economic, political and social sustainability. Digital solutions may reduce costs, increase productivity, improve produce develop, and achieve faster time to market for paludiculture. Digitisation also enables information systems to be open, interoperable, and user-friendly. This constitutes the first study to describe the digital transformation of paludiculture, both vertically and horizontally, in order to inform sustainability that includes process automation via AI, machine learning, IoT-Cloud informed sensors and robotics, virtual and augmented reality, and blockchain for cyber-physical systems. Thus, the aim of this paper is to describe the applicability of digital transformation to actualize the benefits and opportunities of paludiculture activities and enterprises in the Irish midlands with a global orientation.

Life cycle assessment of fish and seafood processed products - A review of methodologies and new challenges.

Life cycle assessment (LCA) has been widely applied in many different sectors, but the marine products and seafood segment have received relatively little attention in the past. In recent decades, global fish production experienced sustained growth and peaked at about 179 million tonnes in 2018. Consequently, increased interest in the environmental implications of fishery products along the supply chain, namely from capture to end of life, was recently experienced by society, industry and policy-makers. This timely review aims to describe the current framework of LCA and its application to the seafood sector that mainly focused on fish extraction and processing, but it also encompassed the remaining stages. An excess of 60 studies conducted over the last decade, along with some additional publications, were comprehensively reviewed; these focused on the main LCA methodological choices, including but not limited to, functional unit, system boundaries allocation methods and environmental indicators. The review identifies key recommendations on the progression of LCA for this increasingly important sustaining seafood sector. Specifically, these recommendations include (i) the need for specific indicators for fish-related activities, (ii) the target species and their geographical origin, (iii) knowledge and technology transfer and, (iv) the application and implementation of key recommendations from LCA research that will improve the accuracy of LCA models in this sector. Furthermore, the review comprises a section addressing previous and current challenges of the seafood sector. Wastewater treatment, ghost fishing or climate change, are also the objects of discussion together with advocating support for the water-energy-food nexus as a valuable tool to minimize environmental negativities and to frame successful synergies.

Novel use of peatlands as future locations for the sustainable intensification of freshwater aquaculture production - A case study from the Republic of Ireland.

There has been an increasing interest in enhancing freshwater aquaculture processes without hindering the progress of the Water Framework Directive. This constitutes the first study to describe a new concept in integrated multitrophic aquaculture (IMTA) that uses cutaway peatlands (bogs) to farm rainbow trout and Eurasian perch with associated organic status that is powered by wind energy and utilizes algae and duckweed to treat rearing water. Approximately 5% of Ireland comprises bogs that support natural ecosystems where there is a pressing need to develop alternative innovation to that of burning peat in order to reduce Ireland's carbon emissions. Specifically, this study evaluates water quality from this new IMTA where intake and terminal holding tank samples were evaluated from May to August 2019. Physicochemical parameters (temperature, pH, nitrogen, phosphorus, oxygen, suspended solids, hardness and alkalinity), and ecotoxicological bioassays (Pseudokirchneriella subcapitata and Daphnia pulex), were used to investigate the potential effects that introducing aquaculture processes may have on peatlands. Nitrite (P < 0.001), nitrate (P = 0.016), and chemical oxygen demand (P = 0.011), were the only physicochemical parameters that differed significantly between the intake and holding tank water indicating that water quality for the most part remained unchanged. Low levels of toxicity were observed between the bioassays suggested the introduction of the processes into the bog were unlikely to cause adverse effects on the ecosystem and the organisms therein. Observations were similar to or lower than those reported previously by other researchers for intensive flow-through aquaculture processes that discharge to receiving water. Findings from this study support the use of peatlands as future locations for integrated aquaculture processes.

Horizontal-flow biofilm reactors for the removal of carbon and nitrogen from domestic-strength wastewaters.

This study investigated the performance of a horizontal-flow biofilm reactor in treating domestic-strength synthetic wastewater (SWW) under three hydraulic and chemical oxygen demand (COD) loading rates (phases 1 to 3) ranging from 152 L/m2 x d and 58.9 g COD/m2 x d to 497 L/m2 x d and 192.7 g COD/m2 x d, respectively; the rates were based on the top surface plan area (TSPA) of the reactor. The reactor comprised a stack of 30 horizontal polystyrene sheets. The SWW, intermittently dosed onto the unit, flowed over and back along sequential sheets in the stack before exiting at the bottom of the unit. Maximum average removals of > 98% biochemical oxygen demand and 96.2% total ammonium-nitrogen (NH4-N) were observed. The TSPA COD and NH4-N removal rates were high for all phases. The unit provides a high-performance, economic, low-maintenance, and flexible alternative for removing carbon and ammonium from low-flow point sources.

Ammonium influences kinetics and structure of methanotrophic consortia.

The literature is conflicted on the influence of ammonium on the kinetics and microbial ecology of methanotrophy. In this study, methanotrophic cultures were enriched, under ammonium concentrations ranging from 0 to 200 mM, from an inoculum comprising leachate and top-cover soil from a landfill. Specific CH4 biodegradation rates were highest (7.8 × 10-4 ±â€¯6.0 × 10-5 gCH4 gX-1 h-1) in cultures enriched at 4 mM NH4+, which were mainly dominated by type II methanotrophs belonging to Methylocystis spp. Lower specific CH4 oxidation rates (average values of 1.8-3.6 × 10-4 gCH4 gX-1 h-1) were achieved by cultures enriched at higher NH4+ concentrations (20 and 80 mM), and had higher affinity for CH4 compared to 4 mM enrichments. These lower affinities were attributed to lower diversity dominated by type I methanotrophs, of the Methylosarcina, Methylobacter and Methylomicrobium genera, encountered with increasing concentrations of NH4+. The study indicates that CH4 oxidation biotechnologies applied at low NH4+ concentrations can support efficient abatement of CH4 and high diversity of methanotrophic consortia, whilst enriching type II methanotrophs.

The impact of arm-crank position on the drag of a paralympic hand-cyclist.

The aerodynamic features associated with the rotation of a cyclist's legs have long been a research topic for sport scientists and engineers, with studies in recent years shedding new light on the flow structures and drag trends. While the arm-crank rotation cycle of a hand-cyclist bears some resemblance to the leg rotation of a traditional cyclist, the aerodynamics around the athlete are fundamentally different due to the proximity and position of the athlete's torso with respect to their arms, especially since both arm-cranks move in phase with each other. This research investigates the impact of arm-crank position on the drag acting on a hand-cyclist and is applied to a hill descent position where the athlete is not pedalling. Four primary arm-crank positions, namely 3, 6, 9, and 12 o'clock of a Paralympic hand-cyclist were investigated with CFD for five yaw angles, namely 0°, 5°, 10°, 15°, and 20°. The results demonstrated that the 3 and 12 o'clock positions (when observed from the left side of the hand-cyclist) yielded the highest drag area at 0° yaw, while the 9 o'clock position yielded the lowest drag area for all yaw angles. This is in contrast to the 6 o'clock position traditionally held by hand-cyclists during a descent to reduce aerodynamic drag.