bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrated real-time control for a sequencing batch reactor plant and a combined sewer system
Authors: Wiese J. , Simon J. , Schmitt T.G.
Published: May 2018

Integrated real-time control (RTC) concepts, which are trying to operate drainage systems and WWTPs depending on the current capacities of both systems, are becoming more and more important. While almost all publications in this field have been concentrating on continuous flow systems, this paper will present a project which has been initiated to realise an integrated RTC strategy for a Sequencing Batch Reactor (SBR) plant in simulation as well as in full-scale. The results of the simulation are that SBR plants can handle high hydraulic loads. The cost–benefit analysis shows that an integrated operation is reasonable concerning environmental and economic aspects. In order to verify the simulation results, full-scale operation has been started in January 2004. The first results seem to confirm the results of the simulation study.
Integrated operation of sewer system and WWTP by simulation-based control of the WWTP inflow
Authors: Seggelke K. , Rosenwinkel K.-H. , Vanrolleghem P. A. , Krebs P.
Published: May 2018

In recent years numerical modelling became a standard procedure to optimise urban wastewater systems design and operation by integration. For dynamic control of the wastewater teatment plant (WWTP) inflow, a model-based predictive concept is introduced aiming at improving the receiving water quality. An on-line simulator running parallel to the real WWTP operation reflects the actual state of operation and provides this model information to a prognosis tool which determines the best option for the WWTP inflow. The investigations showed that it is possible to reduce the NH4-N peak concentrations in the receiving water by dynamic WWTP inflow control based on predictive scenario analysis.
Development of a distributed hydrological model based on urban databanks – production processes of URBS
Authors: Rodriguez F. , Morena F. , Andrieu H.
Published: May 2018

The objective of this study is to present a distributed hydrological model especially dedicated to urban catchments, and able to represent hydrological processes usually neglected in urban modelling, such as evapotranspiration, infiltration in roads, or direct infiltration of soil water in sewers. This model, called URBS (as Urban Runoff Branching Structure) is distributed considering the spatial variability of land use which is well known thanks to urban databanks managed by GIS. The production function is detailed at each cadastral parcel scale, and the runoff produced is routed by a simple transfer function. The estimation of the input parameters of the model is mostly based on physical considerations, and the model is applied on a suburban catchment in Nantes (France) in order to evaluate the interest of the distribution of the hydrological variables.
ArcEGMO-URBAN — Hydrological model for point sources in river basins
Authors: Biegel M. , Schanze J. , Krebs P.
Published: May 2018

The new model ArcEGMO-URBAN aims at deterministic and spatiotemporal modelling of water, nitrogen and phosphorus fluxes from all urbanised areas of a river basin considering all potential sources. Pollution loads are calculated for discrete urban patches and balanced on the level of hydrological sub-basins. Modelling results can be defined by the user of any level of spatial and/or temporal aggregation, e.g. matter balances for river basins or river sections and years or months, respectively. To process spatial data, a Geographic Information System is linked to the model. Information on urban land use and general characteristics of river basins is based on digital coverages, partly generated from remote-sensing data. Moreover, statistical data, e.g. on population, sewer systems, wastewater treatment plants etc. are included. Stormwater runoff from impervious surfaces is calculated as one input to the sewer network. Wastewater is considered with its main sewer system, pumping stations and treatment plants. Finally, the discharge is balanced for discrete river sections. Modelling results attest ArcEGMO-URBAN its ability to realistically quantify matter fluxes and major pollution sources as well as their seasonal variation. This makes the model an applicable tool for the analysis of scenarios with e.g. varying population distribution or climatic and technological conditions.
Reflections on uncertainty in risk assessment and risk management by the Society of Environmental Toxicology and Chemistry (SETAC) precautionary principle workgroup
Authors: Sanderson H. , Stahl C.H. , Irwin R. , Rogers M.D.
Published: May 2018

Quantitative uncertainty assessments and the distribution of risk are under scrutiny and significant criticism has been made of null hypothesis testing when careful consideration of Type I (false positive) and II (false negative) error rates have not been taken into account. An alternative method, equivalence testing, is discussed yielding more transparency and potentially more precaution in the quantifiable uncertainty assessments. With thousands of chemicals needing regulation in the near future and low public trust in the regulatory process, decision models are required with transparency and learning processes to manage this task. Adaptive, iterative, and learning decision making tools and processes can help decision makers evaluate the significance of Type I or Type II errors on decision alternatives and can reduce the risk of committing Type III errors (accurate answers to the wrong questions). Simplistic cost-benefit based decision-making tools do not incorporate the complex interconnectedness characterizing environmental risks, nor do they enhance learning, participation, or include social values and ambiguity. Hence, better decision-making tools are required, and MIRA is an attempt to include some of the critical aspects.
Investigation of biofilm structure, flow patterns and detachment with magnetic resonance imaging
Authors: Manz B. , Volke F. , Goll D. , Horn H.
Published: May 2018

Detachment of biomass from biofilms is still a nearly unknown process which has to be investigated in more detail. Magnetic resonance imaging (MRI) is a promising method which supplies information on the structural data of the biofilm, its surface and the hydrodynamic conditions at the bulk/biofilm interface. Both the structural data and the shear stress are key parameters for understanding biofilm detachment. In this paper a fast quantitative MRI technique was used to investigate the detachment from a heterotrophic biofilm which was grown in a tube reactor. The investigated biofilm was cultivated in a test segment (length 12 cm, diameter 7 mm) of a tube reactor at a constant Reynolds number of 3,000 and a substrate load from 6 g glucose/m2 and day. For the MRI experiments, the test segment with a biofilm of 1,200 μm thickness was connected to the flow loop and placed inside the NMR magnet. During the experiment different hydrodynamic conditions were adjusted for two minutes (Reynolds number Re: 3,000, 4,000, 5,000, 6,000, 7,000, >9,000). Flow velocity and relaxation time were then measured at laminar flow conditions. The MR images show very impressively the increasing detachment of biomass from the biofilm surface with increasing Re. After the last step (Re > 9,000) only a thin biofilm of about 200 μm thickness with a very homogeneous surface remained in the test tube.
Formation and structure of granulated microbial aggregates used in aerobic wastewater treatment
Authors: Ivanov V. , Tay S.T.-L. , Liu Q.-S. , Wang X.-H. , Wang Z.-W. , Tay J.-H.
Published: May 2018

Granular microbial aggregates are used in aerobic treatment of wastewater. The granules have diverse microbial community and complex spatial structure. The structural elements are radial sub-aggregates, concentric layers, channels, pores, polysaccharide plugs, and an anaerobic core of lysed cells. Aerobic bacteria, consisting of 69–84% of microbial biomass, were concentrated in a layer to the depth of 550 μm from the surface of the granule. Facultative anaerobic bacteria, consisting of 9–13% of microbial biomass, dominated in a layer at a depth from 550 μm to 850 μm from the surface of the granule. Obligate anaerobic bacteria, consisting of 2% of microbial biomass, dominated in a layer on the depth from 850 μm to 1,000 μm from the surface of the granule. A core of dead and lysed cells was at a depth greater than 1,000 μm from the surface of the granule. The depth of the anaerobic layer correlated with the appearance of polysaccharide plugs in the pores. Enrichment cultures of microorganisms with high cell surface hydrophobicity or self-aggregation ability can be used to facilitate the formation of microbial granules.
Competitive metabolism of polycyclic aromatic hydrocarbon (PAH) mixtures in porous media biofilms
Authors: Rodríguez S.J. , Bishop P.L.
Published: May 2018

Complex mixtures of polycyclic aromatic hydrocarbons and other organic compounds are usually present in contaminated sites. This may influence biodegradation patterns and changes in biofilm growth and development. Biodegradation studies of naphthalene, phenanthrene and pyrene were conducted in sole-substrate systems and in binary and tertiary mixtures to examine substrate interactions on biofilms in porous media systems. It was shown that phenanthrene and pyrene could not be degraded as sole carbon sources in the system, but binary systems of the 3- and 4-ring PAHs with acetate and naphthalene supplements stimulated their degradation, with up to 87.9% and 70.1% removal efficiencies respectively. However, in the tertiary systems the presence of phenanthrene inhibited pyrene degradation. Adsorption of PAHs to sand media was determined to be negligible. Biofilm growth, development and changes in composition were analyzed over time; these showed increases in both firmly and loosely attached viable biomass, as well as extracellular polymeric substance production that formed a complex matrix. Heterogeneous surface films and a variety of biological aggregate structures and growth patterns were observed by confocal microscopy.
Model-based evaluation of oxygen consumption in a partial nitrification–Anammox biofilm process
Authors: Hao X.-D. , Cao X.-Q. , Picioreanu C. , van Loosdrecht M.C.M.
Published: May 2018

Previous modelling studies indicated that DO was a key factor controlling a partial nitrification–Anammox biofilm process (CANON). As a design parameter, therefore, aeration becomes critical in engineering. Aeration depends on oxygen consumption (OC) taking place in the CANON system which is determined by nitrification, ordinary denitrification, Anammox and even biofilm thickness. Due to the presence of substrate gradients in a biofilm, the amount of OC is difficult to assess with experiments. For that reason, modelling technique was used here to evaluate OC with an expanded CANON model with heterotrophic growth/denitrification involved. Simulations demonstrated that different process/biofilm parameters created different curves of OC, which could help engineers or operators have a better insight into the topic of OC in process design or practical operation.
A mesoscale model for hydrodynamics in biofilms that takes microscopic flow effects into account
Authors: Nguyen V.Th. , Morgenroth E. , Eberl H.J.
Published: May 2018

An extended mathematical mesoscale model for flow effects in a biofilm is developed, allowing flow through the EPS matrix and through microchannels that could not be explicitly resolved in previous mesoscopic simulation studies. The model consists of the usual Navier–Stokes equations in the bulk liquid and a porous medium model in the biofilm itself. The sensitivity with respect to the new model parameter is studied numerically by computer simulations.
Distribution, dynamics and in situ ecophysiology of Crenarchaeota in anaerobic wastewater treatment granular biofilms
Authors: Collins G. , Mahony T. , McHugh S. , Gieseke A. , de Beer D. , O'Flaherty V.
Published: May 2018

The archaeal communities of six anaerobic granular biofilm samples were surveyed for the occurrence of Crenarchaeota, using clone library and terminal restriction fragment length polymorphism (TRFLP) analysis. One of the samples, containing a high abundance of Crenarchaeota-like organisms, was used to inoculate anaerobic reactors for the treatment of a whey-based wastewater. TRFLP was used to monitor the Crenarchaeota-like species during the trial in response to various perturbations. FISH was employed to establish the spatial arrangement of Archaea, Crenarchaeota and Bacteria within biofilm architecture. Radioactive tracer experiments and micro-beta-imaging were used to describe substrate uptake patterns by members of the biofilm. The work represents a groundbreaking effort to investigate the role and in situ functionalism of Crenarchaeota and other groups within biotechnologically important granular biofilm-based ecosystems.
The rapid detection of methyl tert-butyl ether (MtBE) in water using a prototype gas sensor system
Authors: de Lacy Costello B.P.J. , Sivanand P.S. , Ratcliffe N.M. , Reynolds D.M.
Published: May 2018

The gasoline additive Methyl-tertiary-Butyl Ether (MtBE) is the second most common contaminant of groundwater in the USA and represents an important soil contaminant. This compound has been detected in the groundwater in at least 27 states as a result of leaking underground storage facilities (gasoline storage tanks and pipelines). Since the health effects of MtBE are unclear the potential threat to drinking water supplies is serious. Therefore, the ability to detect MtBE at low levels (ppb) and on-line at high-risk groundwater sites would be highly desirable. This paper reports the use of ‘commercial’ and metal oxide sensor arrays for the detection of MtBE in drinking and surface waters at low ppb level (μg.L−1 range). The output responses from some of the sensors were found to correlate well with MtBE concentrations under laboratory conditions.
Water, sanitation and hygiene in developing countries: interventions and diarrhoea—a review
Authors: Fewtrell L. , Colford J.M.
Published: May 2018

We conducted a search to identify all English language papers (published between 1 January 1985 and 26 June 2003) with evidence on the effectiveness of water, sanitation and hygiene interventions in developing countries, in which diarrhoea morbidity in non-outbreak conditions was reported. A total of 39 studies were identified as relevant after an initial review of over 2000 titles. Data were extracted and, where possible, combined using meta-analysis to provide a summary estimate of the effectiveness of specific interventions, including water supply and water treatment. Most of the interventions (including multiple interventions, hygiene and water quality) were found to significantly reduce the levels of diarrhoeal illness, with the greatest impact being seen for hygiene and household treatment interventions (after removal of studies classed as poor quality). Sanitation interventions could not be assessed as only a single study suitable for meta-analysis was identified.
Workshop 6 (synthesis): water for efficient, sustainable fisheries and aquaculture
Authors: Jonch-Clausen T. , Hamrin S. , Linden O.
Published: May 2018

Fisheries must be managed within the framework of river basins, based on the concept of hydrosolidarity between all stakeholders, including respect for downstream interests.
Managing rivers for fisheries and livelihoods: how can we do it better?
Authors: Dugan P.
Published: May 2018

The growing attention being given to improving water productivity at the catchment level has given rise to increased interest in the contribution of aquatic ecosystems and in particular fisheries to reducing rural poverty and improving food security. There is growing recognition that these natural resources have an important role to play in pro-poor water management in many of the world's river basins, but that capacity to optimize these benefits is constrained by a lack of appropriate technologies and tools to do so. The present paper provides an overview of the current state of understanding of these issues and identifies a number of challenges to be addressed, namely the need to: (i) build wider understanding of the value of river fisheries; (ii) understand the water requirements for sustaining river fisheries; and (iii) develop governance arrangements that bring fisheries to the decision-making table. It concludes by distilling from recent reviews of river fisheries valuation, environmental flows, and governance, a set of specific directions that need to be taken in order to meet these challenges.
Workshop 8 (synthesis): water governance – a key driver for food and urban security
Authors: Lenton R. , Tyler S. , Tropp H.
Published: May 2018

Water governance has profound impact on the livelihoods of urban and rural people and on environmental sustainability. Yet governance has not received the same attention as technical issues. Governance is about processes of choices, decisions and estimating trade-offs.
Detection and identification of mycobacteria in the Lisbon water distribution system
Authors: Santos R. , Oliveira F. , Fernandes J. , Gonçalves S. , Macieira F. , Cadete M.
Published: May 2018

Mycobacteria have emerged as a major cause of opportunistic infections. Until the present, only a few studies have characterized mycobacteria present in the water distribution system of urban areas. In this study, we characterize these microorganisms in the Lisbon water distribution system. Our results indicate a high rate of positivities (90.5%) with mainly saprophytic mycobacteria. Around 63% of these results belong to strains of Mycobacterium gordonae indicating a generalized proliferation of this species in the Lisbon water distribution system. A total of 21.05% of the isolates are from M. kansasii, M. intracellulare and M. chelonae.
Steroid estrogens in primary and tertiary wastewater treatment plants
Authors: Braga O. , Smythe G.A. , Schafer A.I. , Feitz A.J.
Published: May 2018

The concentrations of two natural estrogens (estrone (E1) and Estradiol (E2)) and one synthetic progestin (Ethinylestradiol (EE2)) were measured for different unit operations in an advanced sewage treatment plant and in a large coastal enhanced primary sewage treatment plant. The average influent concentration to both plants was similar: 55 and 53ng/L for E1 and 22 and 12ng/L for E2 for the advanced and enhanced primary STPs, respectively. The activated sludge process at the advanced STP removed up to 85% and 96% of E1 and E2, respectively. The enhanced primary sewage treatment plant was mostly ineffective at removing the steroids with only 14% of E1 and 5% of E2 being removed during the treatment process. EE2 was not been detected during the study period in the influent or effluent of either STP. The difference in the observed removal between the two plants is primarily linked to plant performance but the extent to which removal of steroid estrogens is due to bacterial metabolism (i.e. the advanced STP) rather than adsorption to the bacterial biomass remains unclear. The poor removal observed for the coastal enhanced primary STP may have implications for the receiving environment in terms of a greater potential for abnormal reproductive systems in marine animals, particularly if discharges are into large bays or harbours where flushing is limited.
Predicting fate of the contraceptive pill in wastewater treatment and discharge
Authors: Mastrup M. , Schäfer A.I. , Khan S.J.
Published: May 2018

The risk of endocrine disrupters to humans and wildlife is to date poorly understood, although evidence of effects is now widespread. In understanding the risk, an important step is the determination of the partitioning, as well as chemical and biochemical transformation, of compounds in the environment, the water cycle and the food chain. This is a complex task and this paper is a first step towards estimating some of these factors from a largely theoretical approach. A chemical fate model is used to predict the fate of the contraceptive drug 17α-ethinylestradiol (EE2). The example of the contraceptive pill is chosen to follow the journey of the drug from human ingestion and excretion to treatment in a sewage treatment plant (STP) using fugacity-based fate models, followed by discharge into a receiving river and eventually into the estuary/sea. The model predicts how EE2 will partition into the different compartments during each stage of this journey and thereby infiltrate into the food chain. The results suggest that a person would have to ingest more than 30,000 portions of fish to consume an equivalent to a single average dose of the contraceptive pill. While this scenario is highly unlikely, the biochemical consequence of the contraceptive pill is greatly significant. Furthermore, there are many identified similarly estrogenic compounds in the environment while this study only considers one. Cumulative effects of such compounds as well as degradation into other potent compounds may be anticipated. An important message in this paper is the interrelation of wastewater effluent discharge and eventual human exposure of marginally degradable and lipophilic chemicals. While at present the main concerns regarding endocrine disrupters appear to be the fear of their occurrence in drinking water sources, it is clear that the domains of wastewater treatment and discharge, water supply and contamination of food should not be treated as separate issues. The model suggests that exposure from food (contaminated by effluent) may be much more significant than from drinking water.
Applications of artificial neural networks in integrated water management: fiction or future?
Authors: Schulze F.H. , Wolf H. , Jansen H.W. , van der Veer P.
Published: May 2018

An Artificial Neural Network (ANN) is nowadays recognized as a very promising tool for relating input data to output data. It is said that the possibilities of artificial neural networks are unlimited. Here we focus on the potential role of neural networks in integrated water management. An Artificial Neural Network (ANN) is a mathematical methodology which describes relations between cause (input data) and effects (output data) irrespective of the process laying behind and without the need for making assumptions considering the nature of the relations. The applications are widespread and vary from optimization of measuring networks, operational water management, prediction of drinking water consumption, on-line steering of wastewater treatment plants and sewage systems, up to more specific applications such as establishing a relationship between the observed erosion of groyne field sediments and the characteristics of passing vessels on the river Rhine. Especially where processes are complex, neural networks can open new possibilities for understanding and modelling these kinds of complex processes. Besides explaining the method of ANN this paper shows different applications. Three examples have been worked out in more detail. An intelligent monitoring system is shown for the on-line prediction of water consumption, ANN are successfully used for sludge cost monitoring and optimizing wastewater treatment and the usage of ANN is shown in optimizing and monitoring water quality measuring networks. An ANN appears to be a multiuse and powerful tool for modelling complex processes.
Removal of nitrogen in different wetland filter materials: use of stable nitrogen isotopes to determine factors controlling denitrification and DNRA
Authors: Mørkved P.T. , Søvik A.K. , Kløve B. , Bakken L.R.
Published: May 2018

Laboratory incubations with varying O2 and NO3 concentrations were performed with a range of filter materials used in constructed wetlands (CWs). The study included material sampled from functioning CWs as well as raw materials subjected to laboratory pre-incubation. 15N-tracer techniques were used to assess the rates of denitrification versus dissimilatory nitrate reduction to ammonium (DNRA), and the relative role of nitrification versus denitrification in producing N2O. The N2O/(N2+N2O) product ratio was assessed for the different materials. Sand, shell sand, and peat sustained high rates of denitrification. Raw light-weight aggregates (LWA) had a very low rate, while in LWA sampled from a functioning CW, the rate was similar to the one found in the other materials. The N2O/(N2+N2O) ratio was very low for sand, shell sand and LWA from functioning CWs, but very high for raw LWA. The ratio was intermediate but variable for peat. The N2O produced by nitrification accounted for a significant percentage of the N2O accumulated during the incubation, but was dependent on the initial oxygen concentration. DNRA was significant only for shell sand taken from a functioning CW, suggesting that the establishment of active DNRA is a slower process than the establishment of a denitrifying flora.
Dynamic changes in environment condition and microbial community structure in trench and flat seabed sediments of Tokyo Bay, Japan
Authors: Hasanudin U. , Fujita M. , Koibuchi Y. , Fujie K.
Published: May 2018

Dynamic changes in the chemical environment in the bottom of overlying water and microbial community structure in trench and flat seabed sediments were evaluated during summer and autumn in Tokyo Bay, Japan, to elucidate the response of microbial community changes as a consequence of dredging activity. Quinone profile analysis was performed to evaluate the changes in microbial community structure in the sediments. Bottom shape and location of each station affected the chemical environment of the overlying water. The trench bottom shape had longer anoxic conditions than the flat bottom shape. Nitrogen and phosphorus concentrations affected the microbial density in the sediment. During anoxic conditions, the ubiquinone/menaquinone ratio (UQ/MK) was less than unity and increased with rising dissolved oxygen (DO) concentrations. The dominant quinone species in the trench and flat seabed sediments were MK with 6 and 7 isoprene units (MK-6 and MK-7) and UQ with 8 and 9 isoprene units (UQ-8 and UQ-9). MK-6 and UQ-8 containing bacteria might have a great influence on the sulfur cycle of the aquatic ecosystem. While, MK-7 and UQ-9 containing bacteria correlated with the deposition of phototropic bacteria cells onto the seabed sediment. The trench bottom shape contained higher concentrations of MK-6, MK-7, UQ-8 and UQ-9, especially during summer.
Factors affecting the longevity of sub-surface horizontal flow systems operating as tertiary treatment for sewage effluent
Authors: Cooper D. , Griffin P. , Cooper P.
Published: May 2018

Compared with other forms of domestic wastewater treatment, reed beds require very little in the way of operational and maintenance input. This is even more markedly the case with tertiary treatment systems (than with secondary treatment systems) where the necessary maintenance amounts to only a few days/year. Unfortunately, in practice this frequently results in them receiving little or no attention at all. Tertiary treatment reed beds are not a “fit and forget” solution but they are often treated this way because they are very forgiving and abuse-tolerant. After a number of years a few of these tertiary reed beds have deteriorated to an extent whereby they are close to failing to comply with the regulator's requirements. Severn Trent Water Ltd has recognised this situation and has committed a budget for a programme of reed bed maintenance. This work has started with a survey of the condition of their beds and particularly to determine the common problems and hence the maintenance regime required. Five main problems occurred either singly or in combination namely: (a) sludge deposition; (b) above surface flooding (partially caused by (a), (c), and (d)); (c) inlet flow distributor problems/clogging; (d) outlet collector problems/incorrect level; (e) weed infestation.
Root stimulated nitrogen removal: only a local effect or important for water treatment?
Authors: Münch Ch. , Kuschk P. , Röske I.
Published: May 2018

Plants in constructed wetlands serve as carriers for attached microbial growth. They mainly transfer oxygen and release exsudates to the root zone. In consequence of this an area around the roots, called the rhizosphere exists, in which bacteria are stimulated by root growth. The goals were to ascertain whether stimulating the microbial cenosis only has a local effect on the rhizoplane, and to establish the importance of this stimulation for the water purification process in the root zone. Observations were carried out in a laboratory batch reactor filled with sand and planted with reeds (Phragmites australis). A small section was separated with gauze to avoid root growth outside this zone. The reactor was incubated with an artificial waste water containing a high concentration of ammonium. Samples were taken at intervals of 10 mm away from the gauze. The chemical and physical conditions and enzyme activities in soil sections at different distances from the roots affecting the efficiency of nitrogen removal were characterized. An influence was detectable by several parameters up to a specific root distance. Indirect parameters such as the total bacterial number and the DNA amount seem to be affected up to a distance of 50 mm from the root whereas the oxygen amount and DOC are unaffected at a distance exceeding 20–30 mm. This is an initial indication that improved nitrogen removal is also possible in the wider root surroundings. In view of the average root-to-root distance of 35 mm, the root-influenced area could therefore be expanded to the whole rooted zone in a constructed wetland. The influence on bacteria by roots is not just a local effect but may also play an important role in the whole purification process.
Monitor-based evaluation of pollutant load from urban stormwater runoff in Beijing
Authors: Liu Y. , Che W. , Li J.
Published: May 2018

As a major pollutant source to urban receiving waters, the non-point source pollution from urban runoff needs to be well studied and effectively controlled. Based on monitoring data from urban runoff pollutant sources, this article describes a systematic estimation of total pollutant loads from the urban areas of Beijing. A numerical model was developed to quantify main pollutant loads of urban runoff in Beijing. A sub-procedure is involved in this method, in which the flush process influences both the quantity and quality of stormwater runoff. A statistics-based method was applied in computing the annual pollutant load as an output of the runoff. The proportions of pollutant from point-source and non-point sources were compared. This provides a scientific basis for proper environmental input assessment of urban stormwater pollution to receiving waters, improvement of infrastructure performance, implementation of urban stormwater management, and utilization of stormwater.
Retention of Escherichia coli in municipal sewage by means of planted soil filters in two-stage pilot plant systems
Authors: Baeder-Bederski O. , Dürr M. , Borneff-Lipp M. , Kuschk P. , Netter R. , Daeschlein G. , Mosig P. , Müller R.A.
Published: May 2018

Different types of constructed wetlands in a pilot-plant system were fed with identical municipal waste water to compare the sanitisation process in two-stage systems. With combinations of a vertical and a horizontal flow filter an E. coli reduction of 5 log10 with an E. coli influent concentration of 107 MPN/100 ml was achieved. Using different filter materials in each stage the total performance of the two-stage system was independent from the sequence of these materials. However, using coarser filter material in the first stage makes the filter less prone to clogging and is thus the preferential option with regard to operational reliability.
Biomonitoring of polycyclic aromatic hydrocarbons on hepatocellular carcinoma cell line
Authors: Seker S. , Arakawa K. , Sekiguchi M. , Ono Y.
Published: May 2018

Polycyclic aromatic hydrocarbons (PAHs) are not easily degradable and exist as persistent contaminants in water environments. In this study we collected surface sediments and water samples from five different ports around Seto Inland Sea during October 2003 to April 2004. Fifteen PAHs were detected by gas chromatography/mass spectrometer (GC-MS). Expression of CYP1A enzymes was measured by a biochemical activation of 7-ethoxy resorufin ortho-deethylase (EROD). Total water PAHs ranged from 2.5ng/l to 132ng/l, while sediment PAHs ranged from 296.3ng/g to 3992.9ng/g, which indicate low to high level of PAH pollution. Selected isomer ratios (fluoranthene/pyrene to phenanthrene/anthracene and, total molecular weight of 202/total molecular weight 202–278), and detected PAHs suggested that the origin of pollution could mostly be pyrogenic. The highest total sediment PAHs were observed at the Uno Port while the lowest were at the New Okayama Port. EROD activity implied that PAH extracted from sediment samples affected on CYP1A enzymes expression on the human hepatocellular carcinoma cell line in a short exposure time (12 hours). Relatively EROD activity showed good correlation between PAH concentration and CYP1A expression for sediment samples. The highest EROD values were observed for sediment samples at a dose of 5ppm. In contrast water samples were at the low induction level even under the highest exposure concentration (50ppm), except in Mizushima Port. Biomonitoring of water environments by EROD activity could be a necessary tool for understanding the effects of PAHs on living organisms at the base of cell defense.
In-situ monitoring of microbial biomass in wetland mesocosms
Authors: McHenry J. , Werker A.
Published: May 2018

The objective of the present investigation has been to combine tracer principles and a hydrolytic microbial activity assay using fluorescein diacetate to monitor changes in microbial biomass within subsurface flow wetland mesocosms. The mesocosm hydrolytic activity was referenced to activated sludge concentrations treating a typical domestic wastewater at full scale. Microbial biomass activity levels within four laboratory wetland mesocosms treating a synthetic domestic wastewater were routinely monitored over a 21-week period of plant growth and rhizosphere development. Although above ground plant mass and tracer dispersion numbers suggested progressive root zone development, plant growth did not result in any measurable enhancement in microbial activity when compared to a mesocosm operating without plants. Dispersion numbers also suggested a reduction in the mass transport kinetics in these planted mesocosms. In-situ biomass monitoring enabled the assessment of a characteristic response in terms of the steady-state food to microorganism (F/M) ratio that was observed in mesocosms receiving both low and high organic loading. Wetland treatment performance is sensitive to the degree to which bed volume is exploited in terms of wastewater flow to regions of bioactivity. The in-situ reactive tracer technique for mesocosm biomass monitoring provided an assessment of the collective substratum and rhizosphere microbial biomass in direct contact with wastewater contaminants. Thus, in-situ biomass monitoring has application in further understanding of plant function and strategies for plant implementation in wetland research and development.
The effect of the scale of horizontal subsurface flow constructed wetlands on flow and transport parameters
Authors: Suliman F. , French H. , Haugen L.E. , Kløve B. , Jenssen P.
Published: May 2018

Horizontal subsurface flow constructed wetlands have proven their efficiency in treating wastewater and removing the pollutants of concern. Treatment efficiency depends on the wastewater residence time, which is a function of the hydraulic loading and the physical conditions of the constructed filter system, which can be described with effective parameters such as: hydraulic conductivity, porosity, dispersivity etc. Because spatial variability is often scale dependent, these effective parameters may be affected by the scale of the system being studied. In this paper the results of tracer experiments in constructed filters using saturated horizontal flow at three scales (small and medium lab scales and full-scale system) using the same filter media is reported. Light-weight aggregate (filter media termed Filtralite-PTM) was used at all scales. Increasing the scale was associated with increasing dispersivity, meanwhile hydraulic conductivity experienced dramatic reduction and variation by increasing the examined scale. Observed changes in the hydraulic parameters indicate that heterogeneity at different scales should be taken into account when the performance of LWA filters are evaluated from small-scale experiments.
Reduction of bromate in groundwater with an ex situ suspended growth bioreactor
Authors: Butler R. , Godley A.R. , Lake R. , Lytton L. , Cartmell E.
Published: May 2018

A potential remediation technique for groundwater contaminated by bromate has been investigated, utilising biological bromate reduction to bromide by augmentation of indigenous microbial populations. This technique, involving addition of a carbon source to contaminated groundwater, is being developed as an ex-situ methodology analogous to commercial denitrification systems, but may also havein-situ applications. Trials have focussed on a laboratory-scale anaerobic suspended growth chemostat system, investigating glucose addition to real groundwater supplies. Steady states for a range of glucose and bromate concentrations demonstrated bromate reduction up to 700μgl−1 (50% of 1400μgl−1 influent) with glucose excess (above 52mgl−1), but specific reduction rates (up to 2.83μmol Br.g dry wt−1hr−1 for 1400μgl−1 bromate influent) were low compared to denitrification (up to 305μmol Ng dry wt−1hr−1). More recent enrichment trials have demonstrated reduction of 32mgl−1 bromate within a 40 hour residence time with specific reduction rates of up to 160.48μmol Br.g dry wt−1hr−1, suggesting the presence of high rate bromate reducing bacterial strains.
Phosphorus removal in constructed wetlands: can suitable alternative media be identified?
Authors: Arias C.A. , Brix H.
Published: May 2018

Removal of phosphorous in constructed wetlands is limited by the capacity of the media to adsorb, bind or precipitate the incoming P. To enhance P removal and the life span of constructed wetlands the approach might be to use natural sands rich in calcium or iron, to use an alternative ‘artificial’ medium with high P-binding capacity, or to establish external P-binding filters after the wetland. Our studies focused on the evaluation of calcium-rich materials potentially useful as P-binding media. The materials tested included calcite products, natural sands and seashells. Tests included assessment of physical and chemical properties of the materials, extractions in P-spiked water at different P concentrations to determine P-binding equilibrium isotherms, and column experiments. In addition, full-scale tests were performed with calcite in an external filter. The result showed that equilibrium isotherm is an indicator of the potential P-sorption capacity of the media, although the value is of limited application for the determination of the binding capacity in full-scale systems. The columns showed that the materials do bind phosphorus. However, the binding capacities are still insufficient for the establishment of external P-removal filter; the volumes of the filters would be too large to be of practical use.
On-site wastewater management system design and landslide risk assessment
Authors: Whitehead J.H. , Leventhal A.
Published: May 2018

On-site wastewater management system design and performance is significant in assessing landslide risk in areas with potential for slope instability. Much of the development in Pittwater, NSW, local government area is on steep coastal land which has a history of slope instability. Concern over cases of poorly performing or failing on-site wastewater systems and the recognition that these and newly designed systems could be contributory to slope instability has been a factor in Pittwater Council, NSW, requiring that landslide risk assessment be undertaken for new and amended on-site wastewater management systems in potentially unstable areas.

This paper describes the wastewater management system design and landslide risk assessment undertaken at Pittwater Youth Hostel in accordance with the Australian Geomechanics Society's Geotechnical Risk Management procedure to comply with the Pittwater Policy. The work completed illustrates both necessary and effective interaction of the wastewater and geotechnical professions to achieve a successful outcome for the client. It is likely that this professional interaction will be increasingly common along the NSW coast and elsewhere.
Integrated airlift bioreactor system for on-site small wastewater treatment
Authors: Chen S.L. , Li F. , Qiao Y. , Yang H.G. , Ding F.X.
Published: May 2018

An integrated airlift bioreactor system was developed, which mainly consists of a multi-stage loop reactor and a gas-liquid-solid separation baffle and possesses dual functions as bioreactor and settler. This integrated system was used for on-site treatment of industrial glycol wastewater in lab-scale. The strategy of gradually increasing practical wastewater concentration while maintaining the co-substrate glucose wastewater concentration helped to accelerate the microbial acclimation process. Investigation of microbial acclimation, operation parameters evaluation and microbial observation has demonstrated the economical and technical feasibility of this integrated airlift bioreactor system for on-site small industrial wastewater treatment.
On-site greywater treatment and reuse in multi-storey buildings
Authors: Friedler E. , Kovalio R. , Galil N.I.
Published: May 2018

The paper presents a study of a pilot plant treating light greywater for seven flats. The pilot plant combines biological treatment (RBC) with physicochemical treatment (sand filtration and disinfection). The pilot plant produced effluent of excellent quality, meeting the urban reuse quality regulations, and was very efficient in TSS turbidity and BOD removal: 82%, 98% and 96%, respectively. COD removal was somewhat lower (70–75%) indicating that the greywater may contain slowly-biodegradable organics. The RBC (attached growth biological system) was able to retain most of the solids as a result of bioflocculation; further it was proven to have very stable and reliable performance. Faecal coliforms and heterotrophic reductions were very high (100% and 99.99%, respectively) producing effluent that also met drinking water standards. The combination of low organic matter, nutrients and microbial indicators reduces the regrowth and fouling potentials in the reuse system, thus ensuring safe reuse of the treated greywater for toilet flushing.
On-site treatment of a motorway service area wastewater using a package sequencing batch reactor (SBR)
Authors: Del Solar J. , Hudson S. , Stephenson T.
Published: May 2018

A sequencing batch reactor (SBR) treating the effluent of a motorway service station in the south of England situated on a major tourist route was investigated. Wastewater from the kitchens, toilets and washrooms facilities was collected from the areas on each side of the motorway for treatment on-site. The SBR was designed for a population equivalent (p.e.) of 500, assuming an average flow of 100 m3/d, influent biochemical oxygen demand (BOD) of 300 mg/l, and influent suspended solids (SS) of 300 mg/l. Influent monitoring over 8 weeks revealed that the average flow was only 65 m3/d and the average influent BOD and SS were 480 mg/l and 473 mg/l respectively. This corresponded to a high sludge loading rate (F:M) of 0.42 d−1 which accounted for poor performance. Therefore the cycle times were extended from 6 h to 7 h and effluent BOD improved from 79 to 27 mg/l.
The effect of temperature and sludge age on COD removal and nitrification in a moving bed sequencing batch biofilm reactor
Authors: Dulkadiroglu H. , Cokgor E.U. , Artan N. , Orhon D.
Published: May 2018

This study investigates the effect of temperature and the sludge age on the performance of a moving bed sequencing batch biofilm reactor (MBSBBR) for COD removal and nitrification. The experiments are conducted in a lab-scale MBSBBR operated at three different temperatures (20, 15 and 10 °C) with a synthetic feed simulating domestic sewage characteristics. Evaluation of the results revealed that removal of organic matter at high rates and with efficiencies over 90% was secured at all operation conditions applied. The nitrification rate was significantly influenced by changes in temperature but complete nitrification occurred at each temperature. The nitrification rates observed at 20 and 15 °C were very close (0.241 mg NOX-N/m2 d, 0.252 mg NOX-N/m2 d, respectively), but at 10 °C, it decreased to 0.178 mg NOX-N/m2 d. On the other hand, the biomass concentration and sludge age increased while the VSS/TSS ratios that can be accepted as an indicator of active biomass fraction decreased with time. It is considered that, increasing biofilm thickness and diffusion limitation affected the treatment efficiency, especially nitrification rate, negatively.
Influence of extracellular polymeric substances on nitrogen removal in an intermittently-aerated membrane bioreactor
Authors: Nagaoka H. , Nemoto H.
Published: May 2018

Influence of EPS on fouling of intermittent aeration MBR reactor (denitrification MBR) was investigated changing intermittent aeration cycle (10 minute-cycle and 120 minute-cycle) in laboratory-scale reactors using synthetic wastewater. EPS were extracted from bacterial cells using cation resin method and molecular weight fractioning of EPS was conducted using gel chromatography. In both of the reactors, nitrogen removal rate was almost 100% after 50th day although DO concentration was not very high during the aerated phase because of accumulation of nitrifying bacteria in the reactors. In the 120 minutes-cycle reactor, trans-membrane pressure increased more rapidly than in the 10 minutes-cycle reactor. The reason might be that EPS of more than 1000 kDa, which are the main fouling substances, are produced more rapidly in the 120 minute-cycle condition. It was also found that three peaks at around 100 kDa, 500 kDa and 2000 kDa are prominent in EPS in intermittent-aeration MBR irrespective of cycle and higher molecular weight EPS are decomposed to smaller molecular weight EPS on membrane surface.
Changes of the nutrient loads of the Danube since the late eighties: an analysis based on long term changes along the whole Danube River and its main tributaries
Authors: van Gils J. , Behrendt H. , Constantinescu A. , Laszlo F. , Popescu L.
Published: May 2018

The Danube nutrient loads are affected by human impacts mainly from agriculture and wastewater discharges. Knowledge about the Danube nutrient loads and the changes of these loads over time is essential for understanding the changes within the ecosystem of the Black Sea, induced by these loads. The paper shows the long term changes of the nutrient load along the Danube estimated by measurements from different countries and institutions. The results show large differences between Dissolved Inorganic Nitrogen (DIN) and Total Phosphorus (TP). For TP, the Danube River loads show a strong decrease since 1988–1992, especially in the Middle and Lower basin. This change is probably partly connected to the dramatic economic changes in the Middle and Eastern European countries following the collapse of the communist system. The DIN load does not show a decreasing trend in the last decade. The data indicate that there may be a decreasing trend in the anthropogenic emissions, but that such a trend is counteracted by a significantly increasing trend of the Danube discharge in the last decade. The accuracy of the available data is analysed in the paper as well.