bluuebunny/crossref_metadata_2025 huggingface dataset:
Groundwater storage and water security: making better use of our largest reservoir
Authors: Tuinhof A. , Olsthoorn T. , Heederik J.P. , de Vries J.
Published: May 2018

Provision of sufficient storage capacity under growing water demands and increasing climate variability is one the main concerns for water managers in the coming decades. It is expected that 150–300 km3 of additional storage capacity will be needed by 2025 especially in semi-arid and arid regions where changes in climate variability will have most impact on rainfall and drought. Storage of substantial amounts of water can either be above ground, in reservoirs behind dams or underground in aquifers (sub-surface storage). Recharge enhancement through management of aquifer recharge (MAR) and sub-surface storage (SSS) is a known technology and already successfully applied in a number of countries for many years at different scales. MAR-SSS is a flexible and cost-effective means to increase storage capacity both at village level and in modern water management schemes. A dialogue and information exchange between climate experts and water managers can provide an effective contribution to the planning, design and operation of MAR-SSS schemes.
Uncertainty as a monster in the science–policy interface: four coping strategies
Authors: van der Sluijs Jeroen
Published: May 2018

Using the metaphor of monsters, an analysis is made of the different ways in which the scientific community responds to uncertainties that are hard to tame. A monster is understood as a phenomenon that at the same moment fits into two categories that were considered to be mutually excluding, such as knowledge versus ignorance, objective versus subjective, facts versus values, prediction versus speculation, science versus policy. Four styles of coping with monsters in the science–policy interface can be distinguished with different degrees of tolerance towards the abnormal: monster-exorcism, monster-adaptation, monster-embracement, and monster-assimilation. Each of these responses can be observed in the learning process over the past decades and current practices of coping with uncertainties in the science policy interface on complex environmental problems. We might see this ongoing learning process of the scientific community of coping with complex systems as a dialectic process where one strategy tends to dominate the field until its limitations and shortcomings are recognized, followed by a rise of one of the other strategies. We now seem to find ourselves in a phase with growing focus on monster assimilation placing uncertainty at the heart of the science–policy and science–society interfaces.
Carbon sequestration, the precautionary approach and the responsibility of scientists
Authors: Buhl-Mortensen L. , Myhr A. , Welin S.
Published: May 2018

This paper reviews problems connected to the use of the deep-sea and sub-sea geological formations for carbon sequestration. We will focus on the risks and dangers involved in using this kind of large-scale engineering approach, which is not yet fully tested, to combat global warming. We will not provide a complete discussion on the technologies involved, but concentrate on a few principal questions, such as the responsibility of environmental scientists involved in this research. We will also discuss carbon sequestration in relation to the precautionary approach. We argue that there may be a place for large-scale engineering attempts, but this should be the last rather than the first option.
Cadmium transfer and distribution in a multi-species biofilm and the impact on naphthalene removal
Authors: Jin P. , Bishop P.L.
Published: May 2018

Biofilm technology is being introduced into bioremediation of contaminated soils and underground water, in the form of biofilm barriers. However, the low availability of polycyclic aromatic hydrocarbons (PAHs) and toxicity of the frequently accompanying heavy metals may limit its application. The objective of this study was to investigate the mass transfer and distribution of cadmium (Cd) into the biofilm matrix and the impact caused by it. The influences of pH value, presence of an alternative substrate and increased dissolved oxygen were examined. As the pH value increased, cadmium sorption in the biofilm increased and naphthalene removal decreased. Ten mg/L of cadmium was enough to show a significant impact on biofilm when the pH was above 7.5. The cadmium minimum inhibition capacity was determined to be 5μgCd/mgVS. Acetate, added as an alternative substrate, competed with naphthalene and did not demonstrate the ability to reduce cadmium toxicity. Hydrogen peroxide, added to supplement the dissolved oxygen, accelerated the cadmium uptake/efflux cycle, making the biofilm more vulnerable to cadmium attack. Cadmium was shown to transfer faster than naphthalene into biofilm, and the removal of naphthalene in the presence of cadmium was retarded and reduced.
Uranium removal by sulfate reducing biofilms in the presence of carbonates
Authors: Marsili E. , Beyenal H. , Di Palma L. , Merli C. , Dohnalkova A. , Amonette J.E. , Lewandowski Z.
Published: May 2018

Hexavalent uranium [U(VI)] was immobilized in biofilms composed of the sulfate reducing bacteria (SRB), Desulfovibrio desulfuricans G20. The biofilms were grown in two flat-plate, continuous-flow reactors using lactate as the electron donor and sulfate as the electron acceptor. The growth medium contained uranium U(VI) and the pH was maintained constant using bicarbonate buffer. The reactors were operated for 5 months, and during that time biofilm activity and uranium removal were evaluated. The efficiency of uranium removal strongly depended on the concentration of uranium in the influent, and was estimated to be 30.4% in the reactor supplied with 3 mg/L of U(VI) and 73.9% in the reactor supplied with 30 mg/L of U(VI). TEM and SAED analysis showed that uranium in both reactors accumulated mostly on microbial cell membranes and in the periplasmic space. The deposits had amorphous or poor nanocrystalline structures.
Effects of shear stress on the secretion of extracellular polymeric substances in biofilms
Authors: Ramasamy P. , Zhang X.
Published: May 2018

Movement of biofilm into the suspended state as a result of erosion and sloughing is inevitable. The causes for this have been widely attributed to the presence of high shear stress, excess nutrients or a combination of both parameters. It is believed that the extracellular polymeric substances (EPS) of biofilm contribute to the mechanical stability of the biofilm; however, the effect of changing shear stress on the secretion of biofilm EPS is not well understood. This research examined the EPS of a biofilm quantitatively during the change in shear stress. Biofilm was grown in a rotating drum biofilm reactor and subjected to three different shear stresses: 0.1022 N/m2 at 100 rpm, 0.1533 N/m2 at 150 rpm and 0.2044 N/m2 at 200 rpm. Results indicate that a sudden increase of shear stress caused a drastic increase of the EPS-polysaccharides in the biofilm. However, 20 days after each shear increase, the EPS-polysaccharides secretion dropped back to the previous values before the shear change. Physical properties of the biofilm such as porosity were also monitored and the result showed that higher shear stress produced less porous but denser biofilm. Another notable effect when the shear stress was increased was that more erosion of biofilm occurred.
Decision support tools for urban water and wastewater systems – focussing on hazardous flows assessment
Authors: Malmqvist P.-A. , Palmquist H.
Published: May 2018

The Swedish research programme Urban Water has developed a concept of a multi-criteria basis intended to support decision-making for urban water and wastewater systems. Five criteria groups were established for sustainability assessment of urban water systems: Health and Hygiene, Environment, Economy, Socio-culture, and Technology. Each criterion requires a set of indicators corresponding to quantifiable facts and figures, or qualitative data to comparatively assess the different alternatives in the decision process. The decision support process starts as a baseline study where the existing conditions are addressed. Alternative strategies of the future urban water system are developed and analysed by different tools and methodologies in assessing the five criteria groups. Eventually, the results and conclusions are integrated and synthesised into a basis for decision-making.

As an example of a decision support basis for chemical safety, a barrier perspective was introduced to find out if and to what extent hazardous substances can be stopped, diverged, or transformed at various points in the wastewater system. A set of barriers was suggested, i.e. behaviour, systems design, process design, optional recipients, and organisational. The barrier approach was applied to two alternative municipal wastewater system designs – a combined wastewater system vs. a source separated system – analysing the fate of phosphorus, cadmium, and triclosan. The study showed that the combined system caused a higher substance flow to the receiving waterbody than the separated system. The combined system also brought more phosphorus and cadmium to the farmland than the separated system, but only half the amount of triclosan.
Pro-poor strategies for urban water supply and sanitation services delivery in Africa
Authors: Cross P. , Morel A.
Published: May 2018

Water utilities in Africa find it increasingly difficult to provide adequate services to the needy areas: their core business operations are often stagnant, compounded by a dramatic rise in peri-urban and poor settlements. To address these challenges, the Water and Sanitation Program Africa has designed a work program to disseminate the best practice in pro-poor service development and to help utilities and municipal authorities to develop roadmaps to the MDGs for their service areas. Activities will primarily be directed at: (i) helping utilities and municipal authorities to include pro-poor objectives in their reform; and, (ii) working jointly with local partners, CBOs and NGOs, and SSPs to develop strategies and actions specifically targeting informal settlements. WSP-AF will focus on utilities that are engaged in reform or planning to do so. This program builds on support developed for Water Utility Partnership (WUP#5). Key entry points for pro-poor strategies: (i) pro-poor tariffs and financing mechanisms for service improvement, (ii) institutional arrangements to improve services to the urban poor, (iii) pro-poor transaction design (including regulation and monitoring), (iv) advocacy and communications regarding the urban poor, and (v) consumer voice and civil society engagement.
Promoting good governance through regulatory frameworks in African water utilities
Authors: Mwanza D.D.
Published: May 2018

Most public utilities in Africa are operating at very low efficiency levels. This is mainly a result of poor governance leading to a downward spiral in terms of service to customers. Nearly in every case, studies have shown that the root cause of these problems is not necessarily lack of investment but poor choices with regard to sector policies, institutional and regulatory frameworks. The paper will seek to show the need for effective regulatory framework that promotes Good Governance of public utilities leading to their efficient performance. The paper will draw lessons from the Australian water services regulatory framework and apply it to the African water situation. The Australian regulatory framework has been instrumental in promoting Good Governance in the public utilities hence being run efficiently. It is recognised that the African Water and Sanitation Sector where most public utilities are not operating under a clearly defined regulatory framework can learn a lot from the Australian experience.
Urban water recycling
Authors: Asano T.
Published: May 2018

Increasing urbanization has resulted in an uneven distribution of population, industries, and water in urban areas; thus, imposing unprecedented pressures on water supplies and water pollution control. These pressures are exacerbated during the periods of drought and climatic uncertainties. The purpose of this paper is to summarize emergence of water reclamation, recycling and reuse as a vital component of sustainable water resources in the context of integrated water resources management in urban and rural areas. Water quality requirements and health and public acceptance issues related to water reuse are also discussed.

Reclaimed water is a locally controllable water resource that exists right at the doorstep of the urban environment, where water is needed the most and priced the highest. Closing the water cycle loop not only is technically feasible in agriculture, industries, and municipalities but also makes economic sense. Society no longer has the luxury of using water only once.
Effects of aging on the bioavailability and sorption/desorption behavior of biphenyl in soils
Authors: Park J.-H. , Sharer M. , Feng Y. , Chung S.-Y. , Voice T.C. , Boyd S.A.
Published: May 2018

The effects of aging (soil-chemical contact time) on bioavailability, one of the main variables for determining the persistence of organic chemicals in the environment, is poorly understood. There are few studies that have tested the effects of long-term aging on chemical dynamics in soils and have related these effects to bioavailability tests of these aged compounds. In this study, sorption/desorption behavior of biphenyl (BP) on two soil types (Capac A and Capac B) was evaluated for aging times of 24 hours and 8 months. Then bioavailability experiments of BP on the same soils were performed after aging times of 24 hours to 6 months. Sorption isotherms and desorption kinetic profiles were prepared to analyze changes in uptake and release, respectively, due to aging of BP. Mineralization kinetics of BP to 14CO2 by a strain of Pseudomonas putida was used to assess changes in bioavailability due to aging. Data indicates that there was an increase in sorption with aging time for BP on both soil types. The rate of BP desorption did not much change with increased aging time. The extent of BP mineralization was found to decrease with aging time.
Perception of tap water risks and quality: a structural equation model approach
Authors: de Franca Doria M. , Pidgeon N. , Hunter P.
Published: May 2018

The present study aims to test a model of tap water risk and quality perception. A questionnaire was designed and applied to a convenience sample of 499 people in Portugal. The model includes aesthetic variables (colour, odour, and flavour), contextual indicators and risk perception. Other variables were also considered, including external information, trust in water companies, familiarity with tap water, and past water-related health problems. A behavioural outcome – drinking tap water – was also studied. Due to multivariate non-normality (Mardia's Coefficient (G2,P) = 460.3), the AGLS estimator was used for the structural equation model (SEM). A triangulation approach with multivariate regression analysis was used to explain the use of tap water to drink and to propose a more holistic model that could not be tested using SEM. Results show that perceived water quality is largely influenced by flavour. Other factors, such as perceived risk and contextual indicators, also have a role but their relevance is relatively weak. On the other hand, risk perception seems to be mainly a result of external information, past health problems, and water colour. Finally, the use of tap water to drink at home can be moderately explained and depends mostly on the ability to use alternatives (i.e. bottled water), tap water taste, and perceived risk.
Workshop 7a (synthesis): sustainable groundwater management
Authors: Shady A. , Varis O. , Tortajada C.
Published: May 2018

Groundwater, the hidden part of the hydrological cycle, is often overlooked in the freshwater discourse, partly because the damage and changes that human activities cause are not immediately visible. Increasingly across the world, groundwater resources are strained with serious consequences.
A deterministic model to quantify pathogen loads in drinking water catchments: pathogen budget for the Wingecarribee
Authors: Ferguson C.M. , Croke B. , Ashbolt N.J. , Deere D.A.
Published: May 2018

This paper describes the development and testing of a mathematical model as a tool to quantify pathogen loads in Sydney's drinking water catchments. It has been used to identify, quantify and prioritise sources of Cryptosporidium, Giardia and E. coli in the Wingecarribee catchment. The pathogen model promotes understanding of the relative significance of different sources of pathogen risks as well as their fate and transport as they move through the subcatchments. This pathogen model not only enables water utility managers to identify those catchment segments that may contribute the highest load of pathogens, but also where management options will be most effective.
Evidence for the existence of Cryptosporidium oocysts as single entities in surface runoff
Authors: Kaucner C. , Davies C.M. , Ferguson C.M. , Ashbolt N.J.
Published: May 2018

There is uncertainty whether Cryptosporidium oocysts attach to particles or to each other under ambient water conditions. Particle size distributions of Cryptosporidium oocyst suspensions were determined over a range of ionic strengths and pHs to determine under those environmental conditions that may promote oocyst aggregation. Cryptosporidium oocysts were shown to only aggregate in high ionic strength solutions (>0.45 M) and remain largely as single entities at ionic strengths and pHs that were likely to be encountered in surface runoff. Similarly, in loam soil suspensions, rather than attaching to the soil particles the majority of oocysts also remained as single entities. Overall, oocysts are expected to remain largely unattached to either themselves or soil particles in overland runoff. This has implications for pathogen transport and modelling since oocysts that are freely suspended are more likely to be transported in runoff to surface waters than if attached to more dense soil/faecal particles.
Danish guidelines for small-scale constructed wetland systems for onsite treatment of domestic sewage
Authors: Brix H. , Arias C.A.
Published: May 2018

The Danish Ministry of Environment and Energy has passed new legislation that requires the wastewater from single houses and dwellings in rural areas to be treated adequately before discharge into the aquatic environment. Therefore official guidelines for a number of onsite treatment solutions have been produced. These include guidelines for soakaways, biological sand filters, technical systems as well as different types of constructed wetland systems. This paper summarises briefly the guidelines for horizontal flow constructed wetlands, vertical flow constructed wetlands, and willow systems with no outflow and with soil infiltration. There is still a lack of a compact onsite solution that will fulfil the treatment classes demanding 90% removal of phosphorus. Therefore work is presently being carried out to identify simpler and robust P-removal solutions.
Integrated urban water cycle management: the UrbanCycle model
Authors: Hardy M.J. , Kuczera G. , Coombes P.J.
Published: May 2018

Integrated urban water cycle management presents a new framework in which solutions to the provision of urban water services can be sought. It enables new and innovative solutions currently constrained by the existing urban water paradigm to be implemented. This paper introduces the UrbanCycle model. The model is being developed in response to the growing and changing needs of the water management sector and in light of the need for tools to evaluate integrated watercycle management approaches. The key concepts underpinning the UrbanCycle model are the adoption of continuous simulation, hierarchical network modelling, and the careful management of computational complexity. The paper reports on the integration of modelling capabilities across the allotment, and subdivision scales, enabling the interactions between these scales to be explored. A case study illustrates the impacts of various mitigation measures possible under an integrated water management framework. The temporal distribution of runoff into ephemeral streams from a residential allotment in Western Sydney is evaluated and linked to the geomorphic and ecological regimes in receiving waters.
Restoration of fish passage: development and results of a master plan established for the Ruhr river basin
Authors: Weyand M. , Redeker M. , Nusch E.A.
Published: May 2018

According to the central aim of the European Water Framework Directive, the protection and sustained management of the aquatic ecological system, the ecological condition of a specific type of water, will be the primary parameter in future. Aiming at good ecological status in surface water bodies, population diversity and abundance of fish and macroinvertebrates is decisive. Free passage in river systems, to allow the natural migration of fish and all other aquatic organisms, is a prerequisite. To achieve this for the Ruhr River Basin a study has been commissioned in order to develop a master plan for river continuum restoration. Sustainable development aimed at promoting biodiversity in the surface water body system is a key objective. This project is complemented by investigations of the sediment – which is the nursery of the fish – in the rivers to identify river sections or tributaries which obviously provide a suitable habitat for the successful reproduction of big Salmonidae. The master plan illustrates the inherent problems of projects aimed at the restoration of fish passage in water bodies which are strongly affected by anthropogenic modifications. The results obtained may as well be transferred to other catchments with similar use patterns.
Effect of different water management strategies on water and contaminant fluxes in Doncaster,United Kingdom
Authors: Rueedi J. , Cronin A.A. , Moon B. , Wolf L. , Hoetzl H.
Published: May 2018

In Europe, large volumes of public water supply come from urban aquifers and so efficient urban water management and decision tools are essential to maintain quality of life both in terms of health, personal freedom and environment. In the United Kingdom, this issue gained increased importance with the last year's low volumes of groundwater replenishment that resulted in increased water shortages all over the country. An urban water volume and quality model (UVQ) was applied to a suburb of Doncaster (United Kingdom) to assess the current water supply system and to compare it with new potential scenarios of water management. The initial results show considerable changes in both water and solute fluxes for some scenarios and rather limited changes for others. Changing impermeable roads and paved areas to permeable areas, for example, would lead to higher infiltration rates that may be welcome from a water resources viewpoint but less so from a water quality point of view due to high concentrations of heavy metals. The biggest impact on water quality and quantity leaving the system through sewer, storm water and infiltration system was clearly obtained by re-using grey water from kitchen, bathroom and laundry for irrigation and toilet flush. The testing of this strategy led to lower volumes and higher concentrations of sewerage, a considerable decrease in water consumption and an increase in groundwater recharge. The scenarios were tested neither in terms of costs nor social acceptance for either water supplier or user.
Apatite as an interesting seed to remove phosphorus from wastewater in constructed wetlands
Authors: Molle P. , Liénard A. , Grasmick A. , Iwema A. , Kabbabi A.
Published: May 2018

Intensive use of phosphates has resulted in high P levels in surface waters and therefore eutrophication problems. Over the last decade many studies have revealed the advantage of using specific materials with efficient phosphorus retention capacities. Recent studies state that Ca materials are of particular interest for long-term retention of P, but can induce negative effects. To improve P retention and avoid negative counter-effects we tested the potential of natural apatites. Apatite sorption was evaluated using batch and open reactor experiments. Batch experiments identify sorption mechanisms and the influence of the ionic characteristics of the solution; open reactor experiments evaluate sorption capacities in relation to the ionic composition of the solution and biomass development. In parallel, observation of the material by electron microscopy was used to give more precision information about the mechanisms involved. This work reveals the strong chemical affinity between apatites and phosphorus. Compared to other calcareous materials apatite is better able to maintain low outlet P levels. After more than 550 days feeding, sorption was still present and low P outlet levels were still being obtained when sufficient contact time and calcium content in the solution were ensured. This work demonstrates the advantages of using apatites for phosphorus removal in constructed wetlands. The behaviour of apatite in phosphorus retention is explained and its suitability for use in such extensive systems defined.
The role of plant uptake on the removal of organic matter and nutrients in subsurface flow constructed wetlands: a simulation study
Authors: Langergraber G.
Published: May 2018

Plants in constructed wetlands have several functions related to the treatment processes. It is generally agreed that nutrient uptake is a minor factor in constructed wetlands treating wastewater compared to the loadings applied. For low loaded systems plant uptake can contribute a significant amount to nutrient removal. The contribution of plant uptake is simulated for different qualities of water to be treated using the multi-component reactive transport module CW2D. CW2D is able to describe the biochemical elimination and transformation processes for organic matter, nitrogen and phosphorus in subsurface flow constructed wetlands. The model for plant uptake implemented describes nutrient uptake coupled to water uptake. Literature values are used to calculate potential water and nutrient uptake rates. For a constructed wetland treating municipal wastewater a potential nutrient uptake of about 1.9% of the influent nitrogen and phosphorus load can be expected. For lower loaded systems the potential uptake is significantly higher, e.g. 46% of the nitrogen load for treatment of greywater. The potential uptake rates could only be simulated for high loaded systems i.e. constructed wetlands treating wastewater. For low loaded systems the nutrient concentrations in the liquid phase were too low to simulate the potential uptake rates using the implemented model for plant uptake.
Development of communication networks and water quality early warning detection systems at drinking water utilities in the Ohio river valley basin
Authors: Schulte J.G. , Vicory A.H.
Published: May 2018

Source water quality is of major concern to all drinking water utilities. The accidental introduction of contaminants to their source water is a constant threat to utilities withdrawing water from navigable or industrialized rivers. The events of 11 September, 2001 in the United States have heightened concern for drinking water utility security as their source water and finished water may be targets for terrorist acts. Efforts are underway in several parts of the United States to strengthen early warning capabilities. This paper will focus on those efforts in the Ohio River Valley Basin.
Impact of operational maintenance on the asset life of storm reed beds
Authors: Rousseau D.P.L. , Horton D. , Griffin P. , Vanrolleghem P.A. , De Pauw N.
Published: May 2018

This paper reviews the operation of storm reed beds to determine whether the current system of operational maintenance is contributing to premature process failures and if not, to identify other factors of importance. Twelve storm reed beds of the horizontal subsurface flow type, at seven locations in the South Warwickshire area of the United Kingdom, were surveyed. Each survey consisted of a site visit, an interview with the operators in charge and an assessment of the treatment performance based on routine monitoring data. Although some sites suffered from varying degrees of sludge accumulation, surface blinding and/or weed growth, all effluent concentrations remained far below the consent levels. Thorough operational maintenance on a reed bed is proven to be important for the asset life. However, there are other factors or features of a reed bed that play a more pivotal role in premature process failure such as the lack of pre-treatment and a premature operation of the storm overflow.
Influence of biofilm on removal of surrogate faecal microbes in a constructed wetland and maturation pond
Authors: Stott R. , Tanner C.C.
Published: May 2018

The effect of biofilm on the attenuation of pathogen-sized particles from wastewater was compared for biofilms cultivated in a surface flow constructed wetland (SFW) and maturation pond (MP) The fate of fluorescently labelled microspheres (FLM) as surrogates for viruses (0.1 μm), bacteria (1 μm) and parasitic protozoa (4.5 μm dia) was investigated in microcosms in the presence or absence of biofilms. Rates of FLM removal from suspension were higher in the presence of biofilms for all particle sizes (kd 0.02–0.11 h−1) in MP and SFW microcosms with removal efficiency related to particle size and biofilm thickness and structure. Greater removal of 0.1 μm (79–81%), 1 μm FLM (92–96%) and 4.5 μm FLM (up to 98%) from suspension were found for microcosms containing thicker (autotrophic) biofilms grown in the MP or open water zone of the SFW. Lower removal of 43% (0.1 μm), 59% (1 μm) and 84% (4.5 μm) occurred in microcosms containing thinner heterotrophic biofilms from SFW vegetated zones. Providing surfaces for attachment of photosynthetic biofilms offers potential to enhance pathogen removal in open water systems. In vegetated systems, linkage to more oxic openwater zones may allow thicker and ‘stickier’ epiphytic biofilms to develop, improving pathogen interception and removal.
Technology for sustainability: the role of onsite, small and community scale technology
Authors: Ho G.
Published: May 2018

An overview of available onsite, small and community scale wastewater treatment technology shows that it is diverse compared to current technology for centralised collection and treatment of wastewater. An analysis of the onsite, small and community scale technology for achieving sustainability shows that it more conducive to achieving sustainability than the centralised technology. It is likely, however, that its application is in remote and rural areas, where the technology should be improved and integrated with other technology sectors (energy, food production) for improved sustainability. Opportunities exist in new urban developments to achieve similar outcomes, but concerted efforts are required to demonstrate or showcase sustainability benefits in real situations. A huge potential also exists for the use of onsite, small and community scale technology in developing countries for achieving the same sustainability outcomes. It is likely to succeed if the technology is modified to be of lower cost but based on the same science, and that research, development and demonstrations in developed countries are shown to be successful.
Emerging approaches to integrated urban water management: cluster scale application
Authors: Hunt J. , Anda M. , Mathew K. , Ho G. , Priest G.
Published: May 2018

Integrated Urban Water Management (IUWM) seeks to extend Water Sensitive Urban Design to a total water cycle approach that includes reuse of wastewaters. This paper investigates the appropriateness of environmental technologies for application at a cluster scale in IUWM. Many environmental technologies are economically or physically unsuited to use on a municipal or unit scale. Cluster scale is a middle ground that will allow such environmental technologies to achieve full potential. The concept of cluster scale and the application of environmental technologies at this scale are discussed along with some examples of suitable technologies.
Subsurface flow reedbeds using alternative media for the treatment of domestic greywater in Monteverde, Costa Rica, Central America
Authors: Dallas S. , Ho G.
Published: May 2018

This paper describes the performance of reedbeds using plastic (PET) bottle segments as an alternative low-cost media for the treatment of domestic greywater in Monteverde, Costa Rica, Central America. Twelve reedbeds consisting of four sets of triplicates were monitored through wet and dry seasons in order to determine the effect of media type (PET versus crushed rock) and the effect of plants. In both seasons, performance of the planted reedbeds with PET media, for BOD and fecal coliform removal, was either comparable to, or better than, that of the crushed rock systems. The planted PET reedbeds achieved fecal coliform removal rates >99.9% in all cases equating to reductions of between 3 and nearly 5 log, with an average BOD outflow of 12.9 mg/L over both seasons. The hydraulic loading rate varied between 1.33 and 2.67 cm/day and hydraulic retention times (HRT) ranged from 3.5 to 7.5 days. The six reedbeds planted with Coix lacryma-jobi proved to be significantly more effective in pathogen removal and BOD reduction than the unplanted reedbeds. The planted PET reedbeds also increased their biomass by twice that of the planted crushed rock reedbeds during the study period. The majority of this increase was shown to be due to root growth. This paper discusses the implications of the above results for developing countries and identifies potential areas for further research.
Aspects of design, structure, performance and operation of reed beds – eight years' experience in northeastern New South Wales, Australia
Authors: Davison L. , Headley T. , Pratt K.
Published: May 2018

Reed beds (horizontal subsurface flow constructed wetlands) have been employed as secondary treatment devices in on-site and decentralised wastewater management systems in the northeast of the Australian state of New South Wales (NSW) for over a decade. This paper summarises some of the practical and research findings that have come to light in that time. Experience with various aspects of reed bed structure is discussed. A study of the evaporative performance of four small beds planted with Phragmites australis yielded an annual crop factor of 2.6. A total of 28 studies on reed beds treating a variety of commonly encountered wastewater streams yielded the following mean pollutant removal efficiencies: total suspended solids (TSS) 83%, biochemical oxygen demand (BOD) 81%, total nitrogen (TN) 57%, total phosphorus (TP) 35% and faecal coliforms (FC) 1.9 logs. The reed bed is becoming the preferred on-site technology for removing TN and BOD and polishing TSS from primary settled domestic wastewater. Sizing beds for a residence time of approximately five days has become standard practice. A study of six reed beds found six different species of earthworm present, mainly Perionyx excavatus (Indian Blue). A mesocosm experiment subsequently showed that the worms were translocating clogging material from the substrate interstices to the surface of the bed thereby indicating a possible method for prolonging reed bed life.
Monitoring of the process of composting of kitchen waste in an institutional scale worm farm
Authors: Kristiana R. , Nair J. , Anda M. , Mathew K.
Published: May 2018

Vermicomposting provides an alternative method of managing waste that is ecofriendly and cost-effective. The Environmental Technology Centre (ETC) at Murdoch University and St. John of God Hospital (SJOG) signed a Memorandum of Understanding (MOU) to install a vermiculture system in SJOG to treat some of the organic waste generated by the on site kitchen facility. This is an effort made by SJOG to reduce the amount of organic waste sent to landfill each year and to treat the waste on site as part of a recycling/reuse program.

The study is aimed at scientifically monitoring vermicomposting process and to understand the optimum management requirements to improve the operation of an institutional scale worm farm. In addition, an experiment was conducted to investigate the suitability of bedding materials: horse manure, cow manure, peat coir, and natural bedding (vermicast). The species of earthworms used in this experiment were Red (Lumbricus rubellus), Tiger (Eisenia fetida), and Blue (Lumbricus excavatus). The pH, temperature, worm population and quality of castings were tested in different beds.

Results indicated that vermicast was the best bedding for vermicomposting, and there were no significant difference between the performances of the other three beds. However, it can be concluded that the bedding material of horse manure, cow manure, and peat coir were successfully established well within the experimental period of eight weeks, and cow manure with the lowest C:N ratio produced the best quality bedding. As using vermicast for the initial bedding creates a very high capital cost these organic substrates provide cost-effective alternative. Therefore they would be quite appropriate to initiate an institutional scale worm farm.
Greywater recycling systems in Germany — results, experiences and guidelines
Authors: Nolde E.
Published: May 2018

Although Germany is not considered a water-poor country, there exist regional differences in water supply and consumption. During the past 15 years, the greywater aspect has been dealt with in Germany with a greater interest and variable success. In addition to an increased environmental awareness, water costs also play an important role in increasing the demand for advanced greywater treatment plants installed in buildings. Under favourable conditions, the amortisation costs usually lie between 5 and 7 years. Systems that have been extensively tried and tested and have been shown to be most reliable are those employing an advanced biological treatment followed by an UV disinfection. Systems based on membrane technology are being developed and researched intensively in Germany for municipal wastewater treatment. However, so far they play no role in greywater recycling. Greywater systems operating under low energy and maintenance requirements without the use of chemicals are mostly favoured. In Germany, greywater recycling systems should be registered at the Health Office in order to guarantee that no cross-connections exist with the drinking water network and that pipes are labelled according to regulations. The hygienic requirements for recycled greywater, which is primarily used for toilet flushing, are oriented towards the EU-Guidelines for Bathing Waters. The use of recycled greywater for irrigation purposes is minor. As to the use of recycled water for laundry, the first promising investigation results are now available.
The role of membrane technology in sustainable decentralized wastewater systems
Authors: Fane A.G. , Fane S.A.
Published: May 2018

Decentralized wastewater treatment has the potential to provide sanitation that meets criteria for sustainable urban water management in a manner that is less resource intensive and more cost effective than centralized approaches. It can facilitate water reuse and nutrient recovery and can potentially reduce the ecological risks of wastewater system failure and the community health risk in a wastewater reuse scheme. This paper examines the potential role of membrane technology in sustainable decentralized sanitation. It is argued that the combination of membrane technology within decentralized systems can satisfy many of the criteria for sustainable urban water management. In particular, the role of membranes as a dependable barrier in the wastewater treatment process can increase system reliability as well as lowering the latent risks due to wastewater reuse. The modular nature of membranes will allow plant size to range from single dwellings, through clusters to suburb size. It is concluded that realization of the potential for membrane-based technologies in decentralized wastewater treatment will require some progress both technically and institutionally. The areas where advances are necessary are outlined.
Immersed Membrane BioReactor (IMBR) for treatment of combined domestic and dairy wastewater in an isolated farm
Authors: Bick A. , Tuttle J.G.P. , Shandalov S. , Oron G.
Published: May 2018

In many regions dairy farms and milk processing industries discharge large quantities of their wastes to the surroundings posing serious environmental risks. This problem is mostly faced in small dairy farms and isolated communities lacking both central collection and conventional wastewater treatment systems. Dairy wastewater is characterized by high concentrations of organic matter, solids, nutrients, as well as fractions of dissolved inorganic pollutants, exceeding those levels considered typical for high strength domestic wastewaters. With the purpose of treating the combined dairy and domestic wastewater from a small dairy farm in the Negev Desert of Israel, the use of a recent emerging technology of Immersed Membrane BioReactor (IMBR) was evaluated over the course of 500 test hours, under a variety of wastewater feed quality conditions (during the test periods, the feed BOD5 ranged from 315 ppm up to 4,170 ppm).

The overall performance of a pilot-scale Ultrafiltration (UF) IMBR process for a combined domestic and dairy wastewater was analyzed based on the Data Envelopment Analysis (DEA) method. The IMBR performance in terms of membrane performance (permeate flux, transmembrane pressure, and organic removal) and DEA model (Technical Efficiency) was acceptable. DEA is an empirically based methodology and the research approach has been found to be effective in the depiction and analysis for complex systems, where a large number of mutual interacting variables are involved.
Comparative analysis of heavy metal and radionuclide contaminants in Black Sea green and red macroalgae
Authors: Strezov A.S. , Nonova Tz.P.
Published: May 2018

A comparative analysis about the accumulation of heavy metal, natural and technogenic radionuclides from the Black Sea environment in different Bulgarian coastline regions is made. The possibilities to use Chlorophyta and Rhodophyta algae phylums as bioindicators in marine environment are investigated. Environmental contamination in the Black Sea alga species (green and red) was studied from 1992 to 2003. Sampling sites were selected to cover the whole coastal region. Low level gamma spectrometry was used to determine the natural and technogenic nuclide concentrations. The heavy metal concentrations were measured by Atomic Absorption Spectrometry (AAS). The obtained data show that radionuclide and metal concentrations depend on the macrophyte type. Tendencies in the concentration of pollutant variations during the studied period are examined and all data give information about different macrophytic species' ability to accumulate certain elements from one and the same sampling location. All obtained results show that use of macroalgae in marine environmental monitoring reduces the need for complex studies on chemical speciation of aquatic contaminants and makes algae valuable indicators for seawater quality assessment. All data show the lack of serious pollution along the Bulgarian Black Sea coast.
Phytoplankton community and hydrochemical characteristics of the Western Black Sea
Authors: Velikova V. , Cociasu A. , Popa L. , Boicenco L. , Petrova D.
Published: May 2018

Since the early 1990s the persistent reports about the irreversibly degrading Black Sea have started to disappear. A large set of data, reflecting the temporal and spatial variability of microalgae and hydrochemical parameters in Western Black Sea waters (WBS), collected in 2001–2002 (EU 5th FP project “daNubs”), allows us to compare the present-day ecosystem functioning to previous ones and to certainly conclude on positive signs of relaxation. The years 2001 and 2002 were without ample, negative biological and hydrochemical events in the WBS. Nutrient general trend was a decreasing one since the late 1980s, and inorganic phosphorus and nitrogen concentrations were frequently below the method detection limits during summer autumn periods of 2001–2002. The shelf waters were properly oxygenated. The phytoplankton community was producing biomass in a decreasing tendency, especially obviously since 1995. Simultaneously, there was an increase in Si:P and Si:N molar ratios and concurrent increase in the diversity of mass algal species (mainly diatoms) but only a few of them generated exceptional blooms. Reduction of the ratios between phytoplankton and zooplankton biomasses became evident. The observed ecological status in 2001–2002 confirms that the Black Sea is no longer a reference point for progressive water quality deterioration.
Effect of primary sludge fermentation products on mass balance for biological treatment
Authors: Ubay-Cokgor E. , Oktay S. , Zengin G.E. , Artan N. , Orhon D.
Published: May 2018

Laboratory batch experiments were conducted at 20 °C to investigate the potential of primary sludge fermentation for the generation of readily biodegradable substrate and to evaluate the effect of fermentation products on mass balance for organic carbon, nitrogen and phosphorus, emphasizing COD fractionation. Fermentation converted between 18 to 30% of the initial volatile suspended solids in the sludge into soluble biodegradable COD. The volatile fatty fraction of the soluble COD was approximately 85% after the fermentation process. The average volatile fatty acid composition in fermentation involved 50% acetic acid, 33% propionic acid, 9% butyric acid and 8% valeric acid, indicating that the most important volatile fatty acid obtained during the biological fermentation process was acetate with more than half of total VFA concentration, which is one of the most important carbon sources for denitrification and biological nutrient removal processes. The recoverable fraction of the fermented sludge supernatant could potentially increase the readily biodegradable COD content of the primary effluent by 5%, together with a potential increase of the soluble nitrogen and phosphorus content by 2%.
Behavior of an Up-flow Anaerobic Sludge Bed (UASB) reactor at extreme salinity
Authors: Gomec C.Y. , Gonuldinc S. , Eldem N. , Ozturk I.
Published: May 2018

High salinity is one of the most well known inhibitors and salt concentrations above 1% are reported as highly saline. Salt may be found in the main collectors of municipal sewer systems which carry the risk of seawater infiltration and where domestic wastewaters are treated with landfill leachates such cases in Istanbul. Discharging of leachates into sewerage would also result in additional ammonium loads in Municipal Treatment Plants (MTPs). In this study, synthetic wastewater was fed to a lab-scale Upflow Anaerobic Sludge Bed (UASB) reactor operated at a constant hydraulic retention time (HRT) of 1 day. The salt concentration was increased artificially whereas the ammonium concentration was fixed at 1000 mg/l throughout the study. Results indicated no significant inhibition up to 2% salinity + 1000 mg/l NH4 and TOC removals could reach up to 88%. Besides, effective total biogas productions having methane content of 84% could be achieved. It is obvious that anaerobic microorganisms (especially methanogens) could well adapt to high salinity ratios. No inhibition at high ammonium concentration might have been attributed to the fact that the pH in the system was not high enough for the formation of free ammonia. Investigation of the combined effect of high salinity and ammonium was carried on by increasing the salinity to 3% in the study. Results indicated that TOC removals decreased to around 56% and 3% salinity caused a sharp decrease both in organic material removal and total biogas production. Thus the critical salinity level was determined as 3% for the methanogens in the mesophilic anaerobic digesters.