Nutrient Emissions Research Articles

Compiling C/N and total-N dataset to support countrywide soil nutrient emission models for Hungary

Compiling C/N and total-N dataset to support countrywide soil nutrient emission models for Hungary

Carbon and nutrient recycling ecotechnologies in three Baltic Sea river basins – the effectiveness in nutrient load reduction

There exist numerous ecotechnologies for recovery and reuse of carbon and nutrients from various waste streams before they are lost to runoff. However, it remains largely unknown how growing implementation of such ecotechnologies affect nutrient emissions to surface waters at catchment scale. Here, this knowledge gap is addressed by application of SWAT model in three case study catchments draining to the Baltic Sea: Vantaanjoki (Finland), Fyrisån (Sweden) and Słupia (Poland). Sustainability analysis with Multi-Criteria Analysis was applied in the stakeholder workshops in the case study areas to assess different ecotechnology alternatives. The following ecotechnologies received the highest sustainability scores: in Vantaanjoki anaerobic digestion, based on mostly agricultural residues; in Fyrisån source-separation of wastewaters; in Słupia nutrient extraction within the wastewater treatment process. The effect of application of digestate on agricultural soils in the Vantaanjoki catchment was simulated by adjusting the model parameters describing the organic carbon content and physical properties of soil. The results showed small reductions of nutrient loads to the Gulf of Finland. Larger reductions of nutrient loads to Lake Mälaren in Sweden and the Baltic Sea in Poland were achieved as a result of the wastewater treatment upgrades. In the Fyrisån catchment, higher relative reductions were simulated for TN than TP, and in dry years than in wet years. Although the studied ecotechnologies did not show as high effectiveness in nutrient load reduction as combinations of traditional Best Management Practices reported in literature, they do have other multiple benefits including crop yield increase, electricity, heat and bio-based fertilizer production.

Multifunctional perennial production systems for bioenergy: performance and progress

AbstractAs the global population increases and becomes more affluent, biomass demands for food and biomaterials will increase. Demand growth is further accelerated by the implementation of climate policies and strategies to replace fossil resources with biomass. There are, however, concerns about the size of the prospective biomass demand and the environmental and social consequences of the corresponding resource mobilization, especially concerning impacts from the associated land‐use change. Strategically integrating perennials into landscapes dominated by intensive agriculture can, for example, improve biodiversity, reduce soil erosion and nutrient emissions to water, increase soil carbon, enhance pollination, and avoid or mitigate flooding events. Such “multifunctional perennial production systems” can thus contribute to improving overall land‐use sustainability, while maintaining or increasing overall biomass productivity in the landscape. Seven different cases in different world regions are here reviewed to exemplify and evaluate (a) multifunctional production systems that have been established to meet emerging bioenergy demands, and (b) efforts to identify locations where the establishment of perennial crops will be particularly beneficial. An important barrier towards wider implementation of multifunctional systems is the lack of markets, or policies, compensating producers for enhanced ecosystem services and other environmental benefits. This deficiency is particularly important since prices for fossil‐based fuels are low relative to bioenergy production costs. Without such compensation, multifunctional perennial production systems will be unlikely to contribute to the development of a sustainable bioeconomy.This article is categorized under: Bioenergy > Systems and Infrastructure Bioenergy > Climate and Environment Energy Policy and Planning > Climate and Environment

Exploring adoption price effects on life cycle inventory results

The environmental impact of a product may change according to who adopts it, where it is adopted, and how it is used. Market forces are an inherent part of consequential LCA and the practice of coupling economic models with life cycle inventory data has increased in popularity. Nevertheless, the actual relationship between the price of a commodity and potential changes to its life cycle inventory has rarely been discussed explicitly. The adoption price effect refers to a change in a product’s environmental impact associated with a change in price, calculated on a functional unit basis. The price of a product influences the type and quantity of incumbent product(s) it displaces. This study provides insights on when the adoption price of a product is likely to influence its life cycle inventory and also identifies conditions where adoption price is expected to have negligible effects on inventory results. A switchgrass bioenergy case is used to demonstrate the adoption price effect on life cycle inventory results when introducing a new product (i.e., switchgrass) into a system with multiple incumbents (i.e., crops, hay, pasture). This study estimates the adoption price effect on nutrient emissions by coupling biogeochemical models with a simplified economic breakeven model that estimates potential switchgrass adoption. In this case study, high switchgrass prices correspond to nitrate emission reductions that are three times greater than low switchgrass prices (0.67 kg N reduced/Mg switchgrass vs 0.21 kg N reduced/Mg switchgrass). The large adoption price effect found within the Southeastern USA is due to the highly heterogeneous landscape in the region. There is no single dominant land use, each incumbent product has a different environmental baseline, and each is displaced at a different switchgrass price range. Meanwhile, the adoption price effect is expected to be negligible in mostly homogenous landscapes, such as the more commonly studied Corn Belt, which has a single dominant incumbent in the form of corn-soy production. In addition to the specific case study, this analysis discusses general adoption conditions likely to lead to adoption price effects when conducting consequential LCA.

Application performance and nutrient stoichiometric variation of ecological ditch systems in treating non-point source pollutants from paddy fields

Nutrient emissions from paddy fields are one of the main sources of agricultural non-point source (NPS) pollution. Based on the “4R” (Reduce-Retain-Reuse-Restore) strategical system of agricultural NPS pollution control, ecological ditches are effective control measures under the “Retain” system. In this study, the nutrient removal efficiency and stoichiometric variations in three different ecological ditch systems were studied in order to better understand the long-term performance of ecological ditches, and to determine which type of ecological ditch system (Eh, concrete ecological ditch with holes on the wall; Ec, concrete ecological ditch; and Es, soil ecological ditch) is optimal for the removal of agricultural NPS pollutants. The results indicated that the converted ecological ditch (Eh type) significantly reduced nutrient levels in two-year rice season runoff compared to a traditional concrete ditch. The average removal efficiencies of total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) in the converted ecological ditch were 20.8 %, 37.0 %, and 44.4 %, respectively. All ecological ditch types had considerable capacity to remove nutrients in simulated rice season runoff. There were no significant differences in the efficiency of nutrient removal between Eh (TOC 24.1 %, TN 42.8 %, and TP 52.6 %) and Es (TOC 20.3 %, TN 35.7 %, and TP 47.9 %). However, the results indicated that Eh systems could provide a relatively stable environment for plants with increased capacity to maintain biological homeostasis. Of the three ditch types, Ec (TOC 12.9 %, TN 23.3 %, and TP 32.6 %) had a relatively low removal efficiency. Redundancy analysis (RDA) indicated that leaf P content, sediment C:N ratio and root N content were more closely related to water variables, and nutrient stoichiometric characteristics of water, plants, and sediment systems were significantly related to the nutrient removal capacity of ecological ditches (99.5 % of the total variation). It is anticipated that this study will promote further development of the “4R” strategical system, and encourage additional improvements to ecological ditches so they can become more effective in reducing agricultural NPS pollution in the field.

Loose One-Way Coupling of Land Use and Nutrient Emission Models to Assess Effects of Regional Development Scenarios on Catchment Water Quality

Nutrient enrichment and eutrophication can increase when urbanisation and intensification of agriculture production occurs without accompanying mitigation measures to offset impacts from land use transitions. The identification of measures to protect or restore water quality is a challenging exercise, particularly in the context of increasing population and urbanisation. Hence, decision-makers need adequate tools to better understand and evaluate the effects of policy interventions on water management and quality control in urban regions. A model integration method was developed to assess future scenarios of urban development on water quality using land use model Monitoring Land Use/Cover Dynamics and nutrient emission model Source Load Apportionment Model. A case study application investigated how projected changes in urban land use in the most populated region of Ireland, the Greater Dublin Region, impact on water quality. Results for all scenarios indicate increasing losses to water for both phosphorus (18–25%) and nitrogen (9–12%). However, as these scenarios assume that wastewater treatment efficiencies remain static into the future, this study highlights that the magnitude and distribution of investment in urban wastewater collection and treatment will have the greatest impact on changes in future nutrient emissions to water in this urban region. The differences between the development scenarios for diffuse nutrient losses were small in comparison, even though the location of specific land uses varied broadly across scenarios. It was found that the decline of agricultural land cover and replacement with urban development in Dublin region by 2026 as represented by four modelled scenarios resulted in substantial increases in diffuse phosphorus emissions, but only slight changes in diffuse nitrogen emissions. It was shown that the scales of impact from sources of nutrients vary from scenario to scenario and that these should be considered alongside planned mitigation of point sources of nutrient emissions to water. Such information can support physical planners, catchment managers and policy makers to plan accordingly to get the best possible environmental outcomes. The case study application demonstrated that the loose one-way coupling of a land use model and a nutrient emission model can be an effective and inexpensive approach to improve understanding of the effects of urbanisation on water quality and assist in the strategic planning of catchment management and infrastructure investment.

Nutrient dynamics of Sphagnum farming on rewetted bog grassland in NW Germany

The agricultural use of drained peatlands leads to huge emissions of greenhouse gases and nutrients. A land-use alternative that allows rewetting of drained peatland while maintaining agricultural production is the cultivation of Sphagnum biomass as a renewable substitute for fossil peat in horticultural growing media (Sphagnum farming).We studied Sphagnum productivity and nutrient dynamics during two years in two Sphagnum farming sites in NW Germany, which were established on drained bog grassland by sod removal, rewetting, and the introduction of Sphagnum fragments in 2011 and 2016, respectively.We found a considerable and homogeneous production of Sphagnum biomass (>3.6 ton DW ha‐−1 yr−1), attributable to the high nutrient levels, low alkalinity, and even distribution of the irrigation water. The ammonium legacy from former drainage-based agriculture rapidly declined after rewetting, while nutrient mobilization was negligible. CH4 concentrations in the rewetted soil quickly decreased to very low levels. The Sphagnum biomass sequestered high loads of nutrients (46.0 and 47.4 kg N, 3.9 and 4.9 kg P, and 9.8 and 16.1 kg K ha−1 yr−1 in the 7.5 y and 2.5 y old sites, respectively), preventing off-site eutrophication.We conclude that Sphagnum farming as an alternative for drainage-based peatland agriculture may contribute effectively to tackling environmental challenges such as local and regional downstream pollution and global climate change.

Modification of the MONERIS Nutrient Emission Model for a Lowland Country (Hungary) to Support River Basin Management Planning in the Danube River Basin

The contamination of waters with nutrients, especially nitrogen and phosphorus originating from various diffuse and point sources, has become a worldwide issue in recent decades. Due to the complexity of the processes involved, watershed models are gaining an increasing role in their analysis. The goal set by the EU Water Framework Directive (to reach “good status” of all water bodies) requires spatially detailed information on the fate of contaminants. In this study, the watershed nutrient model MONERIS was applied to the Hungarian part of the Danube River Basin. The spatial resolution was 1078 water bodies (mean area of 86 km2); two subsequent 4 year periods (2009–2012 and 2013–2016) were modeled. Various elements/parameters of the model were adjusted and tested against surface and subsurface water quality measurements conducted all over the country, namely (i) the water balance equations (surface and subsurface runoff), (ii) the nitrogen retention parameters of the subsurface pathways (excluding tile drainage), (iii) the shallow groundwater phosphorus concentrations, and (iv) the surface water retention parameters. The study revealed that (i) digital-filter-based separation of surface and subsurface runoff yielded different values of these components, but this change did not influence nutrient loads significantly; (ii) shallow groundwater phosphorus concentrations in the sandy soils of Hungary differ from those of the MONERIS default values; (iii) a significant change of the phosphorus in-stream retention parameters was needed to approach measured in-stream phosphorus load values. Local emissions and pathways were analyzed and compared with previous model results.

Urban Nutrient Emissions in Denmark in the Year 1900

Pre-industrial emission levels can serve as a basis to set emission requirements in current conditions to approximate natural circulation of resources and protect the environment. In Denmark, the year 1900 has been set as a reference for water regulation purposes. Reliable measurements from this time are not available. To define reference conditions, we estimate point source emissions of nutrients from Danish towns in 1900 based on historic documentation and current quantitative data. The flow of nutrients emitted by humans and animals and in industrial wastewater is quantified based on the assessment of typical discharge routes in a set of model towns. We find that point source emissions were significant, with 4261 t nitrogen and 764 t phosphorous emitted from towns in 1900. The main source were human excrements (61%), followed by excrements of animals held in towns (32%) and industry (6%). Further, 59% of nutrients were discharged directly to water, 22% were used as fertilizer on agricultural soil and 19% were emitted to soil via landfills and spills. Current point source emissions of nutrients to water (6600 t N/year and 900 t P/year) are significantly higher, revealing a need for radical reductions if historic emission levels should not be exceeded in the future.

Zero liquid discharge in soilless greenhouse horticulture: solutions to save water and the environment while ensuring an optimal production

Zero liquid discharge (ZLD) should be the future for soilless production. In The Netherlands emission of nutrients and plant protection products to surface water is the main reason to investigate the potentials of cultivation methods without any discharge. In a few other countries water pollution issues is the main motive, but for a majority water shortage and the increasing competition for water of an acceptable quality is reason for the growing need for water efficient cultivation methods. During four years ZLD was investigated for cucumber (2014, 2017) and sweet pepper (2015, 2016). The primary goal was to reuse all drain water, while maintaining a similar yield and quality as in the traditional growing method with regular discharges. To achieve ZLD all practical reasons for growers to discharge the nutrient solution had to be anticipated before. In the ZLD trials technical and strategic solutions were jointly tested and further developed into an adapted growing strategy without any discharge. A number of factors could be mentioned as main reasons for discharge: sodium in the supply water, discharge of filter rinsing water, unbalances in the nutrient solution, no recirculation of the drainwater in the beginning of the cultivation, no disinfection equipment, too low drain storage capacity, appearance of calamities (technical failures) and the amount of remnant nutrient solution left in slabs and tanks at the end of the cultivation. The next step was demonstrating the technical and strategic solutions in a cultivation. In 2014 and 2015 we showed that ZLD-cultivation in stone wool substrate was possible without loss of yield and quality. In 2016 and 2017 the more challenging coir substrate was used to investigate the influence of buffering and sodium accumulation. It appeared that ZLD was possible without loss of production or quality. Appearing problems were more in the field of management of water flows than lack of technical equipment. Special care should come for technical failures of equipment, mostly not enough storage capacity is available.

A Model for Disentangling Dependencies and Impacts among Human Activities and Marine Ecosystem Services.

Understanding and communicating the links among human activities and marine ecosystem services are fundamental for ecosystem-based management, which aims at attaining ecological, economic and social sustainability in the use of our seas. Relationships are typically complex and may differ between geographic areas. Here, an assessment model that combines available quantitative, semi-quantitative and qualitative information, rooted in the DAPSIR (Driver—Activity—Pressure—State—Impact—Response) framework and assessment requirements of the EU Marine Strategy Framework Directive, is developed and applied. Focusing on Swedish marine waters, major human activities at sea are evaluated in relation to their dependencies and impacts on the status of marine ecosystem services. This case study is a consensus assessment based on evaluation of available literature and data. By relating degrees of dependencies and impacts to values of different economic sectors, discrepancies among sectors with respect to their impact versus their monetary value can be identified. In our case, commercial fishing depends on and influences a wide range of ecosystem services, while other sectors, such as shipping, depend little on marine ecosystem services. At the extreme end of the range, pressures from human activities in the past, such as historical nutrient emissions, still have prominent influence on ecosystem services today, entailing considerable losses. Marine tourism and commercial fishing show similar dependencies on ecosystem services, but tourism has a clearly lower impact on ecosystem services and a higher monetary value. The model may serve as a useful tool for communicating and guiding priorities in integrated environmental management and maritime spatial planning.

Etlik Piliç Üretiminde Beslemenin Çevre Kirletici Emisyonlar Üzerine Etkisi

Çevre kirliliği; çeşitli madde ve enerji artıklarının insan faaliyetleri sonucu etrafa yayılması (emisyonu) ve normal ekolojik dengenin bozulması olarak tanımlanır. Hayvansal üretim, bu emisyonun önemli derecede artmasını sağlayan ve ilk sıralarda yer alan insani faaliyetlerden bir tanesidir. Ruminantlar, hayvansal üretimin çevre kirletici emisyon üzerine olan etkilerinde önemli bir paya sahip olmakla beraber; kanatlı hayvan yetiştiriciliğinin ve bunun içerisinde etlik piliç üretiminin etkileri de dikkate alınmaya değerdir. Tüm hayvancılık alanlarında olduğu gibi bu alanda da çevre kirletici emisyon üzerine doğrudan etki eden temel etmen beslemedir. Etlik piliçlerin yüksek düzeydeki besin madde ihtiyaçları ve bu besin maddelerini içeren yemlerin üretim süreçleri; sera gazı, azot ve fosfor emisyonunun artmasına neden olurken; buna bağlı olarak da hava, toprak ve su kirliğinin çoğalmasına yol açarlar. Yem ham protein ve amino asit düzeylerinde değişimlerin yapılması veya bazı yem katkı maddelerinin kullanılması, etlik piliç üretiminden kaynaklanan emisyon değerini etkilemektedir. Bunun yanında yemlerin hayvana sunuluş şekillerinin de yine bu emisyon değerleri üzerine etkisi bulunmaktadır. Bu etkiler dikkate alındığında etlik piliç üretiminden kaynaklanan emisyon değerlerinin azaltılması mümkün gözükmektedir. Bu derlemede, etlik piliçlerin beslenmesinin çevre üzerine etkileri; yem üretimi, gübre ile besin madde salınımı, yemin sunuluşu ve formu ile emisyonun ilişkisi yönünden irdelenmiş; bunlara paralel olarak da çözüm önerileri verilmiştir.

North German Lowland Lakes Miss Ecological Water Quality Standards—A Lake Type Specific Analysis

Despite great efforts in point source reductions due to improved wastewater treatment since 1990, more than 70% of the lakes in Germany have not yet achieved the “good ecological status” according to the European Water Framework Directive (WFD). To elicit lake type-specific causes of this failure, we firstly analyzed the ecological status of 183 lakes in NE Germany (Federal State of Brandenburg), as reported to the European Commission in 2015. Secondly, long-term data of two typical lakes (a very shallow polymictic lake with a large and a deep stratified lake with a small catchment area in relation to lake volume) and nutrient load from the common catchment were investigated. About 64%–83% of stratified and even 96% of polymictic shallow lakes in Brandenburg currently fail the WFD aims. Excessive nutrient emissions from agriculture were identified as the main cause of this failure. While stratified deep lakes with small catchments have the best chances of recovery, the deficits in catchment management are amplified downstream in lake chains, so that especially shallow lakes in a large catchment are unlikely to reach good ecological conditions. If the objectives of the WFD are not questioned, agricultural practices and approaches in land use have to be fundamentally improved.

Effectiveness of ecotechnologies in agriculture for the recovery and reuse of carbon and nutrients in the Baltic and boreo-temperate regions: a systematic map

BackgroundAgriculture is the main sector responsible for nutrient emissions in the Baltic Sea Region and there is a growing pressure to identify cost-effective solutions towards reducing nitrogen and phosphorus loads originating from farming activities. Recycling resources from agricultural waste is central to the idea of a circular economy, and has the potential to address the most urgent problems related to nutrients use in the food chain, such as depletion of natural phosphorus reserves, water pollution and waste management. This systematic map examined what evidence exists relating to the effectiveness of ecotechnologies in agriculture for the recovery and reuse of carbon and/or nutrients (nitrogen and phosphorus) in the Baltic Sea region and other comparable boreo-temperate systems.MethodsWe searched for both academic and grey literature. English language searches were performed in 5 bibliographic databases and search platforms, and Google Scholar. Searches in 36 specialist websites were performed in English, Finnish, Polish and Swedish. The searches were restricted to the period 2013 to 2017. Eligibility screening was conducted at two levels: title and abstract (screened concurrently for efficiency) and full text. Meta-data was extracted from eligible studies including bibliographic details, study location, ecotechnology name and description, type of outcome (i.e. recovered or reused carbon and/or nutrients), type of ecotechnology in terms of recovery source, and type of reuse (in terms of the end-product). Findings are presented here narratively and in a searchable database, and are also visualised in a web-based evidence atlas (an interactive geographical information system). In addition, knowledge gaps and clusters have been identified in the evidence base and described in detail.ResultsWe found 173 articles studying the effectiveness of 177 ecotechnologies. The majority of eligible articles were in English, originated from bibliographic databases and were published in 2016. Most studies with reported locations, and given our boreo-temperate scope, were conducted in Europe and North America. The three most prevalent ecotechnologies in the evidence base (collectively 40.7%) were; soil amendments, anaerobic digestion and (vermi)composting. Manure was the principal waste source used for recovery of nutrients or carbon, making up 55.4% of the all studies in evidence base, followed by a combination of manure and crop residues (22%). There were 51 studies with 14 ecotechnologies that reported on recovery of carbon and nutrients together, predominantly via (vermi)composting and anaerobic digestion. Only 27 studies focused on reuse of recovered nutrients and carbon through soil amendments.ConclusionsThis systematic map report provides an evidence base that can be useful for researchers and decision-makers in policy and practice working on transformation from linear to circular economy in the agricultural waste sector. Three potential topics for future systematic reviews are: (1) effectiveness of products recovered from different types of agricultural wastes as soil amendments or fertilizers; (2) effectiveness of anaerobic digestion as an ecotechnology used for recovery of nutrients and carbon; (3) effectiveness of composting and/or vermicomposting as ecotechnologies used for recovery of nutrients and carbon.

Additionality in Payment for Ecosystem Services Programs: Agricultural Conservation Subsidies in Maryland

Many payment for ecosystem services programs peg subsidy levels to the complexity of conservation projects. We investigate the additionality of conservation subsidies on project complexity using data from Maryland, which has used PES programs aggressively to reduce agricultural nutrient emissions into the Chesapeake Bay. A reduced-form linear model indicates modest overall average additionality. A structural approach using counterfactuals constructed from count data model parameters yields the same overall average but finds that additionality varies with project complexity. These results suggest that projections of agriculture’s potential to lower costs of meeting water quality goals are likely overly optimistic.

Reusing drain water to lower the emission of nutrients in the cultivation of Phalaenopsis

Phalaenopsis is the top-selling ornamental pot plant in the Netherlands, and the area under its production was 242 ha in 2014. Previously, production systems of Phalaenopsis (open or free to drain systems) resulted in high emission of nutrients to the ground and surface water, approximately 1500 kg N ha-1 year-1, in the Netherlands. Little is known of the response of Phalaenopsis to water reuse systems, as orchids have been exempt from recirculation obligations owing to their salt sensitivity. Regulations aimed to reduce nitrogen (N) emissions to a maximum of 150 kg ha-1 year-1 in 2018, with the ultimate goal being 0 kg ha-1 year-1, in 2027. Wageningen University and the Research Business Unit Greenhouse Horticulture were commissioned by the government as well as the Phalaenopsis grower association of the Netherlands to develop a system that could achieve the current goal of a maximum of 150 kg N ha-1 year-1. A recirculation system with UV disinfection and the reuse of drain water was utilized at the experimental site in Bleiswijk. Two recirculation treatments were tested with the aim to maintain the current production and quality levels while also lowering the emissions to the standard of 2018, with the possibility of further improvements to achieve the desired standards for 2027. The aim of the first reuse treatment was to discard small amounts of drain water to keep sodium at a maximum of 1.2 mmol L-1. In the second treatment, as much drain water was reused as possible. Emissions of N were reduced to 182 and 60 kg ha-1 year-1, respectively. Plant growth parameters including leaf number, total leaf area, and number of spikes and flowers, showed no significant differences. In this experiment reuse of drain water reduced emissions considerably without any adverse effects on plant growth or disease incidence.

On Waters

S03: One Health: On animals, humans and the environment, Room 417, Floor 4, August 26, 2019, 10:30 AM - 12:00 PM Environmental water influences human health in many ways. Health benefits include the use of water for domestic purposes, food production, transport, energy production and recreation. Health risks are created by exposure to polluted water – often through the same pathways. Pressures from the environment can result in changes in the state of the water body, causing for instance chemical pollution, microbiological contamination, or the presence of disease vectors, such as insects. Water bodies used by people are often influenced by animals, increasing emissions of nutrients and potentially pathogens, or creating ideal mosquito breeding sites. The concept of One Health helps to understand water-related human health risks resulting from the interactions between environment, people and animals around water systems. Interventions in design and water management have the potential to address several health issues at the same time. Systematic and integrated planning and management of water resources from a One Health perspective can contribute to reducing or preventing negative health impacts and enhancing the health benefits.

Retention soil filters for the treatment of sewage treatment plant effluent and combined sewer overflow

Retention soil filters (RSFs) are vertical flow constructed wetlands. They are mainly used for the treatment of combined sewer overflow or stormwater, and not operated during dry weather conditions. However, RSFs have been successfully tested as continuous post treatment for sewage treatment plant effluents. In this paper we present a new approach, namely dual usage of the retention soil filter. During dry weather the RSF is used for the polishing treatment of sewage treatment plant effluent and during overflow events, the retention soil filter treats the combined sewer overflow. This study was conducted at two pilot RSFs that were fed with sewage treatment effluent for four years. Removal of TOC, DOC, nutrients and 21 organic micropollutants was determined during six months at different sequences of regular effluent and overflow treatment conditions. TOC, DOC and nutrients, appearing in high concentration in combined sewer overflow, were effectively removed, and metformin and caffeine micropollutants showed >99% removal. Residues from this combined sewer treatment that were sorbed on filter material or stored in pore water were washed out directly after treatment when STP effluent infiltration was initiated. This effect declined within 20 h after combined sewer overflow treatment. Dry periods of 18 h between combined sewer and sewage treatment plant effluent feeding counteracted the wash out effects. The highest removal efficiency was found in the beginning of the feeding time of 28 h, indicating that shorter feeding cycles enhance the overall efficiency of the RSF. Finally, the results show that a single RSF system can successfully reduce emissions of TOC, DOC, nutrients and micropollutants to surface waters from two different emission pathways, i.e. from regular treated effluents and storm related sewer overflows. In conclusion, the dual usage of RSF is a promising approach and ready for upscaling and implementation.

Water use efficiency of Irish dairy processing

Dairy processing uses a significant amount of water for processing and cleaning. Withdrawing and distributing water and treating wastewater represent significant costs to the Irish dairy processing industry. Stringent discharge limits also add pressure for water use efficiency, particularly during peak production months. Improving water use efficiency is therefore critical for Irish dairy processing. We conducted a detailed analysis of water use efficiency in 4 Irish dairy processing plants. Using farm gate to processor gate (gate-to-gate) life cycle assessment, we assessed on-site water data quality and investigated gate-to-gate volumetric water use and eutrophication potential (EP) for 3 common dairy products. We also benchmarked the on-site water use and water balance, characterized wastewater nutrient load, analyzed the influencers of on-site water use, and identified scope for increased water use efficiency. We found that condensate from evaporation represented a significant input at the site level (0.51 to 1.14 L/L of fresh water purchased or extracted from nature). In terms of gate-to-gate volumetric water use, butter used 1,326 to 1,843 m3/t of solids, with electricity being the largest contributor, whereas milk powders used 3,006 to 3,754 m3/t of solids, with electricity and ingredients being the largest contributors. Eutrophication of butter was found to be 0.51 to 0.77 kg of PO4equivalents (eq)/t of solids, with transportation and nutrient emissions from wastewater treatment being the largest contributors. Eutrophication of milk powder was found to be 0.96 to 3.35 kg of PO4eq/t of solids, and contributions varied depending on powder specifications. Milk intake water use and various leakages were found to be hotspots that could be managed to reduce water use on site. Comprehensive metering is urgently needed to improve water use efficiency in light of the ongoing expansion of dairy production and hence processing in Ireland. Significant opportunities exist to optimize operator behavior, water reuse, and off-site transportation and energy. This study represents the first attempt to define water efficiency opportunities both at the site level and along the supply chain. Processors need to be aware of off-site contributors that significantly affect both volumetric water use and environmental impacts of processed dairy products.

A dynamic life cycle assessment of green infrastructures.

As stormwater and its associated nutrients continue to impair our nation's waterways, green infrastructures (GIs) are increasingly applied in urban and suburban communities as a means to control combined sewer system overflows and stormwater related pollutants. Although GIs have been widely studied for their life cycle impacts and benefits, most of these studies adopt a static approach which prevents that information from being scaled or transferred to different spatial and temporal settings. To overcome this limitation, this research utilizes a dynamic life cycle assessment (LCA) approach to evaluate seven different GIs by integrating a traditional LCA with a system dynamics model which simulates the daily loadings and treatments of nutrients by the GIs across a 30-year life span. A base model was first developed, calibrated, and validated for seven GIs that are currently installed on the campus of the University of New Hampshire. The base model was then expanded to assess different scenarios in terms of geographic locations, land uses, GI design sizes, and climate changes. Our results show these aforementioned factors have significant influences on GIs' life cycle performances, with life cycle nitrogen reductions varying -100.90 to 512.09kgNeq. and life cycle phosphorous reductions varying from -23.77 to 63.43kg P eq. Furthermore, nutrient loading thresholds exist for certain GIs to offset nutrient emissions from their construction and maintenance activities. Accordingly, an optimal GI design size can be estimated for a given spatial and temporal setting. Such thresholds and optimal sizes are important to be identified to inform the decision-making and future planning of GIs.