bluuebunny/crossref_metadata_2025 huggingface dataset:
Sustainable stormwater concepts as an essential instrument for river basin management
Authors: Becker M. , Raasch U.
Published: May 2018

The Emscher system, with its open wastewater drains, has been undergoing reconstruction since 1990. The watercourses, now relieved of the burden of wastewater, are being reconstituted as close to nature as possible. An important precondition, for which naturally orientated rainwater management concepts must be implemented in this densely populated region, is a homogenized run-off. Emschergenossenschaft has in recent years provided financial and conceptual support for the implementation of such changes. Present-day experience demonstrates that disconnection of 10% of impervious areas within the next fifteen years is a realistic target and consequently the aim for next year’s work. As detailed studies using precipitation run-off models document, this will decisively improve the flood and minimum water situations of the small tributary watercourses in particular, which is important regarding the aims of the EU WFD.
Measures for structural improvement with regard to the good status of water bodies - estimation of expenditure for a river basin in Germany
Authors: Grünebaum T. , Morgenschweis G. , Nusch E.A. , Schweder H. , Weyand M.
Published: May 2018

To achieve the objective of “good chemical and ecological status” in water bodies as stipulated by the European Water Framework Directive (WFD) in particular, a package of measures geared to improving the water bodies’ hydromorphology will be required. These upgrading measures can, to some extent, also be seen as an alternative to still more advanced measures in the field of wastewater treatment and stormwater treatment in the context of status improvement in water bodies. On account of the very high level of wastewater and stormwater treatment already achieved, additional efforts in this specific area would, as experience has shown, not only be extremely costly, but produce just moderate if not minor results. In an estimate of the funding required to achieve “good status” by hydromorphological change, undertaken for the Ruhr River Basin (German state of North Rhine-Westphalia), it was found that costs would be in the range of €200 million to €1 billion. This translates into inhabitant-specific costs of €100 to €500 per capita. All measures are to be put into practice within the scope of an integrated water body development concept, optimised with regard to space and time.
Assessment of sustainable water management for rapidly developing urban regions in Guangzhou City, China
Authors: Eastcott J.L. , Aramaki T. , Hanaki K. , Li Z. , You J.
Published: May 2018

The Shawan River will be the focal point in the development of the Panyu District, the southern-most district of Guangzhou City in the Guangdong Province of South China. In this research, through the use of two scenarios, the future water quality of the Shawan River was predicted with relation to changes in the water quantity utilized to fuel industrial and domestic development. The worst-case scenario used, simulated the situation if no wastewater treatment was employed, and the best-case scenario simulated the situation if 90% of the pollution load was removed. The period of simulation was for the years 2020 and 2050. Three flowrates were used in the evaluation, those of: the 90% probability of the month of lowest flow (37.2 m3/s); and the range of flowrates within the low flow period, that is, the dry season from November to February (307 and 432 m3/s). Subsequently, two countermeasures (industrial and domestic water savings) - sustainable initiatives - were nested within the two scenarios to ascertain improvements in water quality as a direct result of reduction in water quantity used. The industrial water saving countermeasure showed the greatest improvement in water quality. For the 90% probability of lowest flow for the worst-case scenario, this countermeasure equated to a 63% decrease in BOD. For the low flow period flowrates the background concentration of pollutants was more influential than improvements imparted by the countermeasures to the future predicted water quality. It was recommended that industrial countermeasures be used that take into account water saving, water recycling, the use of brackish water for cooling, and the implementation of economic pricing initiatives. Also that inter-district governmental policy initiatives be introduced to prevent upstream pollution from influencing downstream proposals, further enhancing sustainable water management of the Shawan River.
Enhancing oxidation of TNT and RDX in wastewater: pre-treatment with elemental iron
Authors: Oh S.-Y. , Cha D.K. , Chiu P.C. , Kim B.J.
Published: May 2018

Munitions manufacturing wastewater is commonly treated by adsorption to activated carbon. We are proposing a new munitions manufacturing wastewater treatment system consisting of a reductive pre-treatment process and subsequent Fenton's oxidation to mineralize energetic compounds such as TNT and RDX. The pre-treatment involves reduction of electron-withdrawing nitro groups of TNT and RDX with elemental iron. The iron-treated explosives are then oxidized by Fenton's reagent through the addition of H2O2. The objective of this work is to investigate the feasibility of using elemental iron to convert TNT and RDX to reduction products which may be more oxidizable in subsequent Fenton's oxidation. Results of batch reduction experiments with elemental iron showed complete removal of TNT and RDX and formation of the reduction products within 60 minutes. Results of column experiments showed a rapid and complete removal of TNT and RDX within 9.7 minutes retention time. Fitting observed effluent concentrations to a one-dimensional advection-dispersion equation, we were able to predict the concentration profiles of TNT and RDX in the iron column and calculate the iron column length required for the desired removal. The results of Fenton's oxidation experiments showed that iron pre-treatment enhanced both the rate and extent of TNT and RDX mineralization by Fenton's oxidation.
Functional metal-binding proteins by metal-stimulated bacteria for the development of an innovative metal removal technology
Authors: Antsuki T. , Sano D. , Omura T.
Published: May 2018

Heavy metal pollution has become an environmental problem throughout the world because heavy metals can be accumulated into the food chain and bring about serious problems, not only for ecosystems but also for human health. In this study, functional metal-binding proteins (FMBPs) were isolated from a metal-stimulated activated sludge culture with the aim of applying them to an innovative metal removal technology. Activated sludge bacteria was cultured in growth media including copper ion, and the stimulation of protein production by copper ion led to the 14% increase in a quantity of extracted crude proteins per 1 g of bacterial cell pellet (wet). In order to isolate FMBPs, extracted crude proteins were applied to the immobilized metal affinity column in which each of copper, nickel and zinc was used as a ligand. Several FMBPs were succesfully isolated from copper-stimulated bacteria. One of FMBPs (molecular weight of about 40 kDa) exhibited an ability to adsorb all three metals. The multi metal-binding property of this FMBP could be applied to an innovative metal removal technology. Furthermore, isolated FMBPs that could capture only one kind of heavy metal would also be attractive as a metal adsorbent in recovering a specific metal as a resource from wastewater, including several heavy metals.
Gas analysis reveals novel aerobic deammonification in thermophilic aerobic digestion
Authors: Yi Y.-S. , Kim S. , An S. , Choi S.I. , Choi E. , Yun Z.
Published: May 2018

A laboratory-scale thermophilic aerobic digester was operated with piggery wastewater. The operating temperature varied from 50-70°C. It has been found that excessive nitrogen removal occurred in the laboratory-scale thermophilic system at various HRTs. Nitrite and nitrate were not observed in the effluent. Gas measurement reveals the presence of significant amount of N2O along with NH3 gas. The rational production of N2O gas in accordance with temperature and HRT suggests that biologically mediated deammonification processes significantly contribute to the N removal. Although further microbiological investigation is required to clarify the exact nitrogen removal mechanism, the large production of N2O gas seems to be a result of the existence of a rapid growing heterotrophic deammonification process in the thermophilic system.
Process water treatment at the Ranger uranium mine, Northern Australia
Authors: Topp H. , Russell H. , Davidson J. , Jones D. , Levy V. , Gilderdale M. , Davis G. , Ring R. , Conway G. , Macintosh P. , Sertorio L.
Published: May 2018

The conceptual development and piloting of an innovative water treatment system for process water produced by a uranium mine mill is described. The process incorporates lime/CO2 softening (Stage 1), reverse osmosis (Stage 2) and biopolishing (Stage 3) to produce water of quality suitable for release to the receiving environment. Comprehensive performance data are presented for each stage. The unique features of the proposed process are:•recycling of the lime/CO2 softening sludge to the uranium mill as a neutralant,•the use of power station off-gas for carbonation,•the use of residual ammonia as the pH buffer in carbonation; and•the recovery and recycling of ammonia from the RO reject stream.
Anoxic phosphorus removal by denitrifying heterotrophic bacteria
Authors: Lacko N. , Drysdale G.D. , Bux F.
Published: May 2018

The unexplained occurrence of anoxic phosphorus (P) accumulation has largely hampered modeling of nitrification denitrification biological excess P removal (NDBEPR) systems. The aim of this study was, therefore, to isolate and identify denitrifying - P accumulating heterotrophic bacteria (DPBs) from a NDBEPR system in order to evaluate anoxic P accumulation and the specific mechanisms involved. Results of the study showed various heterotrophic bacteria to be capable of anoxic P accumulation utilising nitrate (NO3) as electron acceptor. While Pseudomonas spp. predominated, Serratia spp. and Vibrio spp. demonstrated the most efficient anoxic P accumulation with 7.10 and 7.29 mgPO4-P/L removal, respectively, at an initial NO3 concentration of 13.54 mgNO3-N/L and P concentration of 16.34 mgPO4-P/L. Weaker DPBs were also identified which were only capable of accumulating small amounts of P at low initial P and NO3 concentrations due to weak denitrification capacity. Anoxic P release was also observed due to the presence of acetate.
Nutrient removal from wastewaters using high performance materials
Authors: Mackinnon I.D.R. , Barr K. , Miller E. , Hunter S. , Pinel T.
Published: May 2018

Return side streams from anaerobic digesters and dewatering facilities at wastewater treatment plants (WWTPs) contribute a significant proportion of the total nitrogen load on a mainstream process. Similarly, significant phosphate loads are also recirculated in biological nutrient removal (BNR) wastewater treatment plants. Ion exchange using a new material, known by the name MesoLite, shows strong potential for the removal of ammonia from these side streams and an opportunity to concurrently reduce phosphate levels. A pilot plant was designed and operated for several months on an ammonia rich centrate from a dewatering centrifuge at the Oxley Creek WWTP, Brisbane, Australia. The system operated with a detention time in the order of one hour and was operated for between 12 and 24 hours prior to regeneration with a sodium rich solution. The same pilot plant was used to demonstrate removal of phosphate from an abattoir wastewater stream at similar flow rates. Using MesoLite materials, >90% reduction of ammonia was achieved in the centrate side stream. A full-scale process would reduce the total nitrogen load at the Oxley Creek WWTP by at least 18%. This reduction in nitrogen load consequently improves the TKN/COD ratio of the influent and enhances the nitrogen removal performance of the biological nutrient removal process.
Design of nutrient removal activated sludge systems
Authors: Manga J. , Ferrer J. , Seco A. , Garcia-Usach F.
Published: May 2018

A mechanistic mathematical model for nutrient and organic matter removal was used to describe the behavior of a nitrification denitrification enhanced biological phosphorus removal (NDEBPR) system. This model was implemented in a user-friendly software DESASS (design and simulation of activated sludge systems). A 484-L pilot plant was operated to verify the model results. The pilot plant was operated for three years over three different sludge ages. The validity of the model was confirmed with data from the pilot plant. Also, the utility of DESASS as a valuable tool for designing NDEBPR systems was confirmed.
The effect of low sludge age on wastewater fractionation (SS, SI)
Authors: Haider S. , Svardal K. , Vanrolleghem P.A. , Kroiss H.
Published: May 2018

In lab-scale experiments at the 2-stage activated sludge pilot plant of Vienna's central WWTP it is shown that the wastewater soluble COD concentration, which is inert to a sludge with SRT < 1 d (SIA) is about double compared to the SI concentration in sludge with SRT > 10 d (SIB). Unexpectedly the ratio of SIA/SIB is independent of the sludge age between SRTs of 0.4 and 1.0 days. The difference between the two SI fractions is soluble COD that is readily biodegradable by the sludge with SRT > 10 d. However, it is degraded at a lower maximum growth rate. These results comply with earlier results gained with different methods and at different WWTPs. It is hypothesised that very low sludge ages result in a selection of fast growing bacteria, which can utilise only part of the SS in the raw wastewater. The other part of SS therefore remains in the wastewater and can thus be utilised for enhanced denitrification in the second stage.

It is still unknown beyond which sludge age the soluble inert COD SIA starts to decrease, finally reaching the value SIB for low loaded systems (SRT > 5 days). From this point on SI and SS are assumed only to depend on the wastewater composition and not on the sludge age. The assumption of the Activated Sludge Model No.1 that the biodegradable fractions can be modelled as a single substrate and by a single removal kinetic (one Monod term) appears not to be applicable for low sludge ages. Some suggestions for mathematical modelling, design and operation of 2-stage activated sludge systems are given.
Oxygen transfer into activated sludge with high MLSS concentrations
Authors: Krampe J. , Krauth K.
Published: May 2018

In this report, tests on the impact of the sludge properties on the oxygen transfer at low and high solids contents are presented. Additional to the oxygen transfer tests, the activated sludge was intensively analysed to examine the changes of the α-factor in relation to the sludge properties (rheology, EPS, CST, etc.). The a-factor did strongly decrease in all sludge types at increasing MLSS or increasing viscosity, respectively. In the second test stage, the impact of the aeration system was examined in detail. For these tests, the same sludge from a membrane bioreactor was used throughout. Apart from the impact of the power density in the reactor and the specific air throughput, the main focus was on the economic efficiency of the examined systems in cases of high MLSS. It became apparent that up to solids contents of 18 g/l the fine-bubble aeration is the most economically efficient method.
Application of information technology to decision support in treatment plant operation
Authors: Olsson G. , Newell B. , Rosen C. , Ingildsen P.
Published: May 2018

This paper reviews decision support methodologies that can be applied to treatment plants. Case studies of decision support systems (DSS) that have been developed and used or trialled are presented below. These include rule-based systems and systems based on digraphs of cause-and-effect relationships. Detection examples on real plant data are presented, in one case using direct measurements and simple detectors and in another using multivariate statistics and clustering.
Anaerobic hydrolysis of primary sludge: influence of sludge concentration and temperature
Authors: Ferreiro N. , Soto M.
Published: May 2018

Anaerobic hydrolysis of primary sludge from urban wastewater treatment was first studied as part of anaerobic sludge stabilisation and later as a process for readily biodegradable matter (volatile fatty acids) production in order to improve biological nutrient removal. Furthermore, hydrolysis was found to be the rate limiting step in both single- or two-step anaerobic treatment of domestic wastewater. However, the influence on the process of several factors such as sludge concentration and temperature is still barely understood, as are kinetic aspects. The aim of this work was to study the influence of sludge concentration and temperature on the hydrolytic and acidogenic conversion of primary sludge and to determine the hydrolysis kinetic coefficients at different temperatures. Specific VFA production varied from 0.17 to 0.34 gVFACOD/gVSS of raw primary sludge, depending mainly on the assay sludge concentration and, to a lesser extent, on the process temperature. The first-order hydrolysis constants were 0.038, 0.095 and 0.169 d−1 for 10, 20 and 35°C, respectively.
Aral Sea and sustainable development
Authors: Usmanova R.M.
Published: May 2018

Until 1960 the Aral Sea was considered the 4th largest lake in the world by surface area. The Aral Sea has two main inflows - the Amudarya and Syrdarya rivers with about 30 tributaries. From early 1960s because of extensive water use - unreturned withdrawal of water for irrigation and consequent drying up of many tributaries before reaching the main rivers - the water level in the Aral Sea began falling very rapidly. In 1965 the Aral Sea received about 56 cubic km of fresh water yearly, but this number fell to zero by the early 1980s.

By 1990 the level of the Aral Sea water fell by more than 17 m, the volume of water decreased by 75%, the salinity of seawater increased up to 30 g/l, and the surface area of the sea reduced from 66,400 sq. km to 31,500 sq. km.

The ecological situation in Aral Sea zone has became very dramatic. It has led to the changing of climate in the region, irrigated soils becoming deserts, deterioration of underground and surface water quality, reducing of available water for domestic and agricultural needs, loss of Aral Sea fishing and transportation importance, numerous other problems and finally put the health of present and future generations under threat.

This situation not only does not promote further development of the economy of the region, but has also caused damage with irreparable negative consequences. The fact is that the basis of the regional economy is fishing and other associated businesses. Since Uzbekistan is most agricultural country its economy has serious complications. In order to prevent further deepening of this catastrophe and to improve the present situation in this area the Government of the Republic of Uzbekistan has developed a series of measures: in particular it developed efficient water use schemes, changing the cotton situation (that during the Soviet period was grown as monoculture) by planting less water-consuming varieties, reviewing using of fertilizers in agriculture etc. The Aral Sea drought became an international disaster. World Bank, UNESCO, BMBF and others attacked the problem to protect the Aral Sea.
Water recycling: a major new initiative for Melbourne - crucial for a sustainable future
Authors: Arbon M. , Ireland M.
Published: May 2018

Melbourne Water has adopted a challenging target of recycling 20 per cent of treated effluent from Melbourne's two major sewerage treatment plants by 2010. This target was adopted in response to key drivers for water recycling in the Melbourne region such as: strong support for conserving water resources and protecting marine environments; acknowledgment of recycled water as a valuable resource; greater emphasis on environmental issues and sustainable management principles; and opportunities to increase demand for recycled water through effective planning mechanisms. Issues that must be effectively addressed to meet the target include: managing public perceptions of recycled water; health and environmental concerns; lack of consensus among government agencies; high up-front costs of infrastructure; and prices of other sources of water supply not currently true costed. Melbourne Water has identified the following factors as critical in determining the success of recycling strategy: ability to demonstrate that water recycling will be important in terms of long term water cycle management; effective stakeholder consultation; gaining government support; establishing long-term, guaranteed markets for recycled water; implementing well planned, large scale recycling schemes; ability to provide a product that meets customer needs; regulatory approval; and implementation of a system that is economically viable. Water recycling initiatives are being investigated on household, local and regional levels. Over 10 proposals that will contribute to the 20 per cent recycled water target from the regional treatment plants are under various stages of development. Melbourne Water's commitment to recycling within a total water cycle management context is a vital component of this major new initiative for Melbourne and is crucial for a sustainable future.
Management strategies for a eutrophic water supply reservoir - San Roque, Argentina
Authors: Antenucci J.P. , Alexander R. , Romero J.R. , Imberger J.
Published: May 2018

Possible management strategies to improve water quality in a eutrophic water supply reservoir in Argentina were evaluated using the one-dimensional coupled hydrodynamics and water quality model DYRESM-CAEDYM. The model was used to determine the effects of several different artificial destratification system designs (including both bubble plume diffusers and surface impellers with draft tubes, both separately and in combination), on the biomass of the potentially toxic cyanobacteria Microcystis aeruginosa. The best results were found by using a combination of a deep and shallow diffuser, to break down the seasonal thermocline and therefore limit sediment nutrient release and anoxia, and to enhance vertical mixing in the surface mixed layer, respectively.
Use of active barriers to reduce eutrophication problems in urban lakes
Authors: Hart B. , Roberts S. , James R. , Taylor J. , Donnert D. , Furrer R.
Published: May 2018

Excessive concentration of phosphorus is one of the main causes of algal blooms and eutrophic conditions in lakes. In many urban lakes, it appears that a large proportion of the phosphorus in the water column comes from the sediments, particularly when these are anaerobic. Sub-aqueous capping is a relatively new method that has become an attractive option for isolating contaminated sediments from the environment, thus preventing or delaying the release of contaminants into surface waters. Active barrier materials (i.e. capping layers that consist of one or more reactive components) are gaining increasing attention for their greater efficiency in inactivating contaminants held in sediment layers. This paper reports laboratory bioreactor experiments to test the effectiveness of three forms of calcium carbonate (CaCO3) in reducing the release of phosphorus from anaerobic sediment from Lake Carramar, a small urban lake in Melbourne. Two of the CaCO3 active barrier materials tested proved to be quite effective, the most effective materials being the fine particle size, precipitated forms of CaCO3. Over the 20-day experimental period, a 2% layer of the German material SoCal reduced the amount of phosphorus released by almost 100 times over that occurring with no barrier. The Australian product ESCal, while not as effective as the SoCal, still reduced the phosphorus released by around 15 times that with no barrier. A finely ground Lilydale limestone was essentially ineffective in reducing phosphorus release from the sediments. A preliminary cost-benefit analysis suggests that SoCal is unlikely to be attractive for use in Australia, given the estimated application cost of around $3,800 per tonne. However, although the ESCal is slightly less effective in retaining phosphorus, its potential application cost estimated at $2,000 per tonne, makes it an attractive option. On the basis of these most promising preliminary results, we intend to further test the use of the ESCal. Further investigations will include: longer term laboratory studies using ESCal, optimisation of the barrier layer and methods for applying this material, mesocosms and full lake studies, and risk assessment studies to ensure there are no adverse ecological effects from its use.
Buffer distances for on-site sewage systems in Sydney's drinking water catchments
Authors: Charles K. , Roser D. , Ashbolt N. , Deere D. , McGuinness R.
Published: May 2018

Pathogens and nutrients released from on-site sewage systems represent a risk to surface and ground water quality, particularly where there are sensitive receiving waters such as in drinking water catchments. Buffer zones between on-site systems and waterways are one barrier used to protect water quality. The increased time and distance they provide increases the opportunities for the effluent purification functions of the soil to occur. A risk management model is proposed to assess the efficacy of the buffer zones in Sydney's drinking water catchments. The model is the basis for the development of performance based setback distances for on-site systems from waterways, and incorporates stochastic analysis of pathogen and nutrient transport in the environment and consideration of the effluent quality variability from on-site systems. Catchment-scale integration of contaminant transport is employed to facilitate a risk assessment of on-site systems. The risk management model also allows for the impact of on-site system management and maintenance on catchment water quality to be assessed through scenario building and feedback mechanisms.
Dryland salinity in Western Australia: managing a changing water cycle
Authors: Taylor R.J. , Hoxley G.
Published: May 2018

Clearing of agricultural land has resulted in significant changes to the surface and groundwater hydrology. Currently about 10% of agricultural land in Western Australia is affected by dryland salinity and between a quarter and a third of the area is predicted to be lost to salinity before a new hydrological equilibrium is reached. This paper develops a general statement describing the changes to the surface and groundwater hydrology of the wheatbelt of Western Australia between preclearing, the year 2000 and into the future. For typical catchments in the wheatbelt it is estimated that average groundwater recharge and surface runoff have increased about tenfold when comparing the current hydrology to that preclearing. Saline groundwater discharge and flood volumes have also increased significantly. Saline groundwater discharge and associated salt load will probably double in the future in line with the predicted increase in the area of dryland salinity. In addition, future increases in the area of dryland salinity/permanent waterlogging will probably double the volumes in flood events and further increase surface runoff in average years. The outcomes of surface and groundwater management trials have been briefly described to estimate how the hydrology would be modified if the trials were implemented at a catchment scale. These results have been used to formulate possible integrated revegetation and drainage management strategies. The future hydrology and impacts with and without integrated management strategies have been compared.
Estimation of urban runoff and water quality using remote sensing and artificial intelligence
Authors: Ha S.R. , Park S.Y. , Park D.H.
Published: May 2018

Water quality and quantity of runoff are strongly dependent on the landuse and landcover (LULC) criteria. In this study, we developed a more improved parameter estimation procedure for the environmental model using remote sensing (RS) and artificial intelligence (AI) techniques. Landsat TM multi-band (7bands) and Korea Multi-Purpose Satellite (KOMPSAT) panchromatic data were selected for input data processing. We employed two kinds of artificial intelligence techniques, RBF-NN (radial-basis-function neural network) and ANN (artificial neural network), to classify LULC of the study area. A bootstrap resampling method, a statistical technique, was employed to generate the confidence intervals and distribution of the unit load. SWMM was used to simulate the urban runoff and water quality and applied to the study watershed. The condition of urban flow and non-point contaminations was simulated with rainfall-runoff and measured water quality data. The estimated total runoff, peak time, and pollutant generation varied considerably according to the classification accuracy and percentile unit load applied. The proposed procedure would efficiently be applied to water quality and runoff simulation in a rapidly changing urban area.
The vortex concentrator for suspended solids treatment
Authors: Lee J. , Bang K. , Choi J. , Ketchum L.H. , Cho Y.
Published: May 2018

The use of vortex concentrators is becoming increasingly popular for suspended solids reduction in combined sewer overflows and stormwater. This study is a laboratory investigation of the use of vortex concentrators to reduce the solids concentration of synthesized stormwater. The synthesized stormwater was made with water and addition of particles; sand, granular activated carbon, and sewer sediments. The vortex concentrator was made of acryl resin 300 mm in diameter. To determine the efficiency for various influent suspended solids (SS) concentrations, tests were performed with different SS concentrations. The samples were taken simultaneously at the influent storage tank and effluent tank, and measured SS concentrations. The range of surface loading rates were 120 to 850 m3/m2/day, and influent SS concentrations were varied from 300 to 5,000 mg/L. To determine the optimum coagulant dosage, jar tests were conducted with coagulants such as PAM and PAC. It was found that optimum coagulant and its dosage were PAM and 2 mg/L. The overall SS removal efficiency of the vortex concentrator for typical stormwater was estimated at about 65%. With an increase of SS concentration, the removal efficiency was increased. Since the SS concentration of stormwater was higher than 1,000 mg/L, the removal efficiency of the vortex concentrator for stormwater could be estimated to be 65-70%. The SS removal efficiency was increased with an increase of retention time, and the optimum retention time was 0.15-1.0 minutes. With an increase of the foul to overflow QF/Qo, a key parameter for vortex concentrator operation, the removal efficiency was increased. An alternative solution to improve treatment efficiency might be to set a follow-up retention basin. Based on a series of settling tests on the treated overflow water from the vortex concentrator, 5 to 10 minutes hydraulic retention time in a follow-up retention basin would substantially improve the results.
Changes in water quality parameters due to in-sewer processes
Authors: Boxall J. , Shepherd W. , Guymer I. , Fox K.
Published: May 2018

Combined sewer systems contain a large number of organic and inorganic pollutants from both domestic and industrial sources. These pollutants are often retained within the combined sewer system for significant lengths of time before entering sewage treatment works, or being spilt to a watercourse via a combined sewer overflow (CSO) during storm conditions. Currently little knowledge exists concerning the effects of in sewer processes on pollutants. Understanding of in-sewer processes is important for the effective and efficient design of treatment works and CSO chambers and for impact assessments on receiving waters.

A series of studies covering storm and dry weather flow conditions were undertaken with the aim of investigating the nature of in-sewer processes. These studies consisted of marking a body of water with a fluorescent tracer. The tracer was then monitored at a series of downstream sites, and discrete samples collected from the body of water as it progressed through the sewer. The samples were analysed for water quality parameters and these results investigated in tandem with the detailed hydraulic information gained through the tracer studies. The results highlight the hydraulic differences between storm and dry weather conditions such as increased travel times and mixing under storm conditions. The Advection Dispersion Equation (ADE) and Aggregated Dead Zone (ADZ) model parameters have been quantified for the tracer data. The ADE mixing coefficient is shown to increase by an order of magnitude for storm conditions. The ADZ dispersive fraction parameter is shown to be approximately constant with flow. Chemical reactions and decay within the sewer system were found to be consistent with oxygen limitation.
Bioaerosols from the land application of biosolids in the desert southwest USA
Authors: Brooks J.P. , Tanner B.D. , Josephson K.L. , Gerba C.P. , Pepper I.L.
Published: May 2018

This study evaluated bioaerosol emissions during land application of Class B biosolids in and around Tucson, Arizona, to aid in developing models of the fate and transport of bioaerosols generated from the land application of biosolids. Samples were collected for 20 min at distances between 2 m and 20 m downwind of point sources, using an SKC BioSampler® impinger. A total of six samples were collected per sampling event, which consisted of a biosolid spray applicator applying liquid biosolids to a cotton field. Each application represented one exposure. Samples were collected in deionised water amended with peptone and antifoam agent. Ambient weather conditions were also monitored every 10 min following initiation of sampling. Concurrently with downwind samples, background (ambient) air samples were collected to compensate for any ambient airborne microorganisms. In addition, biosolids samples were collected for analysis of target indicator and pathogenic organisms. Soil samples were also collected and analysed. Significant numbers of heterotrophic plate count (HPC) bacteria were found in air samples collected during the biosolid application process. These could have arisen from soil particles being aerosolised during the land application process. Aerosolised soil may contribute significantly to the amount of aerosolised microorganisms. Soil particles may be able to more readily aerosolise, due to their low density, small particle size and low mass. Aerosolised HPC bacteria found during biosolids land application were similar to those found during normal tractor operation on non-biosolids applied fields. Coliforms and coliphages were not routinely detected even though they were found to be present in the biosolids at relatively high concentrations, 106 and 104/g (dry weight) of biosolids respectively. This could be due to the die-off rate of aerosolised Gram-negative bacteria or sorption to the solid portion of the biosolids. Low numbers of aerosolised coliphages may likewise be due to sorption phenomena. We theorise that only organisms in the aqueous phase of the biosolids were available to desorb and be aerosolised. Animal viruses, which were not detected in the biosolids, were likewise not detected in the aerosol samples. Clostridium perfringens was detected in only a small percent of aerosol samples although it was detected during all weather conditions; other microorganisms were detected during more favourable environmental conditions (relative humidity >10%). Despite the fact that many of these organisms were present in the biosolids at significant concentrations, their presence in bioaerosols generated during the land application of biosolids was limited to only a small percentage of samples. Bacteria as well as viruses may sorb to biosolids, which contain a high percentage of organic matter, and desorption during land application of biosolids may not readily take place; therefore, these microorganisms may not be readily aerosolised.
The relationship between composition and toxicity of tannery wastewater
Authors: Cotman M. , Zagorc-Končan J. , Žgajnar-Gotvajn A.
Published: May 2018

Key toxic components have been identified in pre-treated tannery wastewater with fractionation of samples through chemical and physical means (filtration, air stripping, adsorption on activated carbon, …). The goal of each fractionation step was to reduce the toxicity due to a specific group of chemicals and compare the results to the toxicity present in the unaltered sample. Toxicity short-term tests with the invertebrate Daphnia magna and the bacterial luminescence inhibition test with Vibrio fischeri were used in combination with chemical analyses. During the toxicity identification and evaluation fractionation, a portion of the sample was pressure filtered. Treated samples contained less organic pollution and metals and were less toxic especially to Daphnia magna. For the removal of ammonia the second portion of sample was air-stripped at different pH levels. We removed 84% of ammonia at pH 11; the toxicity to both organisms decreased but ammonia did not have a deciding effect on the toxicity of tannery wastewater when the organic load was still present. The most successful procedure for toxicity removal was adsorption on powdered activated carbon. We removed organic pollution detected as COD, organic nitrogen compounds and part of the metals. Zeolite treatment was a little less successful for removing ammonia than air-stripping.
Photocatalytic oxidation of volatile organic compounds present in airborne environment adjacent to sewage treatment plants
Authors: Raillard C. , Héquet V. , Le Cloirec P. , Legrand J.
Published: May 2018

Emissions of volatile organic compounds (VOCs) from wastewater in municipal sewage or industrial wastewater treatment plants are often overlooked as sources of exposure to hazardous substances. The impact of such emissions on local airborne environments represents a growing source of scientific, toxicological and public health interest. Actually, VOCs are suspected to be quite dangerous for human health. Some of them belong to the family of odorous compounds and can cause serious annoyance in the neighbourhood of the emission sources. A way to remove VOCs released from sewers and wastewater treatment facilities could be to degrade them by photocatalytic oxidation. TiO2-based photocatalysts are known to be efficient for this kind of application. In the present work TiO2 P25 Degussa was deposited on glass supports. These materials were tested for the degradation of butanone-2 in a photocatalytic reactor. The influence of water vapour (relative humidity) was shown using the Langmuir-Hinshelwood kinetic model.
Safe household water treatment and storage using ceramic drip filters: a randomised controlled trial in Bolivia
Authors: Clasen T. , Brown J. , Suntura O. , Collin S.
Published: May 2018

A randomised controlled field trial was conducted to evaluate the effectiveness of ceramic drip filters to improve the microbiological quality of drinking water in a low-income community in rural Bolivia. In four rounds of water sampling over five months, 100% of the samples were free of thermotolerant (faecal) coliforms (TTC) compared to an arithmetic mean TTC count of 1517, 406, 167 and 245 among control households which continued to use their customary sources of drinking water. The filter systems produced water that consistently met WHO drinking-water standards despite levels of turbidity that presented a challenge to other low-cost POU treatment methods. The filter systems also demonstrated an ability to maintain the high quality of the treated water against subsequent re-contamination in the home.
Probing Norwalk-like virus presence in shellfish, using artificial neural networks
Authors: Brion G. , Lingeriddy S. , Neelakantan T.R. , Wang M. , Girones R. , Lees D. , Allard A. , Vantarakis A.
Published: May 2018

A database was examined using artificial neural network (ANN) models to investigate the efficacy of predicting PCR-identified Norwalk-like virus presence and absence in shellfish. The relative importance of variables in the model and the predictive power obtained by application of ANN modelling methods were compared with previously developed logistic regression models. In addition, two country-specific datasets were analysed separately with ANN models to determine if the relative importance of the input variables was similar for geographically diverse regions. The results of this analysis found that ANN models predicted Norwalk-like virus presence and absence in shellfish with equivalent, and better, precision than logistic regression models. For overall classification performance, ANN modelling had a rate of 93%, vs 75% for the logistic regression. ANN models were able to illuminate the site-specific relationships between indicators and pathogens.
Virological analysis of shellfish for food safety and control
Authors: Carducci A. , Lucchesi N. , Casini B. , Mazzoni F. , Liaci D. , Verani M.
Published: May 2018

The present study was performed in order to obtain reliable and applicable techniques of viral detection in shellfish for use in ensuring food safety. This research was developed in two steps: (a) different techniques to recover viruses from artificially contaminated shellfish were tested and (b) the best technique was applied to analyse shellfish collected from sites along the coast of Salento.
Elimination of viruses, bacteria and protozoan oocysts by slow sand filtration
Authors: Hijnen W.A.M. , Schijven J.F. , Bonné P. , Visser A. , Medema G.J.
Published: May 2018

The decimal elimination capacity (DEC) of slow sand filters (SSF) for viruses, bacteria and oocysts of Cryptosporidium has been assessed from full-scale data and pilot plant and laboratory experiments. DEC for viruses calculated from experimental data with MS2-bacteriophages in the pilot plant filters was 1.5-2 log10. E. coli and thermotolerant coliforms (Coli44) were removed at full-scale and in the pilot plant with 2-3 log10. At full-scale, Campylobacter bacteria removal was 1 log10 more than removal of Coli44, which indicated that Coli44 was a conservative surrogate for these pathogenic bacteria. Laboratory experiments with sand columns showed 2-3 and >5-6 log10 removal of spiked spores of sulphite-reducing clostridia (SSRC; C. perfringens) and oocysts of Cryptosporidium respectively. Consequently, SSRC was not a good surrogate to quantify oocyst removal by SSF. Removal of indigenous SSRC by full-scale filters was less efficient than observed in the laboratory columns, probably due to continuous loading of these filter beds with spores, accumulation and retarded transport. It remains to be investigated if this also applies to oocyst removal by SSF. The results additionally showed that the schmutzdecke and accumulation of (in)organic charged compounds in the sand increased the elimination of microorganisms. Removal of the schmutzdecke reduced DEC for bacteria by ±2 log10, but did not affect removal of phages. This clearly indicated that, besides biological activity, both straining and adsorption were important removal mechanisms in the filter bed for microorganisms larger than viruses.
Primary silver extraction with a high sulphur activated petroleum coke
Authors: Schouwenaars R. , Durán Moreno A. , Ramírez Zamora R.M.
Published: May 2018

An extended study was performed to determine the mechanisms that are responsible for the significant silver extraction capacity of activated carbons prepared from a high-sulphur petroleum coke that is available as a waste material from Mexican petroleum refineries. Earlier studies had shown the feasibility of the production of these adsorbents but indicated that the mechanisms of metal adsorption in the present carbons are significantly different from what is classically accepted for commercial carbons. Therefore, selective titration, IR-spectroscopy and scanning electron microscopy of carbons were combined with adsorption experiments and the determination of electrochemical parameters of mixtures of carbon-AgNO3 solution to explain the fundamental reasons for the performance of the obtained carbons. This allowed us to determine the identity of the surface functional groups and to distinguish the effect of different activation processes. The experiments permitted us to explain why these activated carbons, which have a low specific area and lack classical surface functional groups, show such a high silver adsorption capacity.
Lead removal by a natural polysaccharide in membrane reactors
Authors: Reddad Z. , Gérente C. , Andrès Y. , Le Cloirec P.
Published: May 2018

Industrial wastewaters often contain heavy metal ions that are toxic to many living species. Therefore, economic treatment methods are investigated, involving the sorption of metal ions onto wastes or natural materials. In the present work, the ability of sugar beet pulp, a common waste of the sugar industry, to remove Pb2+ polluted waters is investigated. The kinetic and equilibrium experiments were performed in batch reactor in order to determine the Pb2+ adsorption mechanisms onto the polysaccharide. The dynamic studies of Pb2+ fixation onto the natural polysaccharide involve an adsorption reactor coupled with microfiltration membrane in order to confine the adsorbent particles. A mass balance model based on the Langmuir equilibrium isotherm was used to describe the Pb2+ breakthrough curves. This model successfully simulated the entire breakthrough curves whatever the operating conditions used. It provides a useful tool for process simulation and optimisation.
Molecular typing of the Legionella pneumophila population isolated from several locations in a contaminated water network
Authors: Lepeuple A.-S. , Jovic M. , de Roubin M.-R.
Published: May 2018

The RAPD (random amplified polymorphic DNA) technique has been developed for the molecular typing of Legionella in order to characterise the populations of hot water systems. During this study, 22 primers were tested and the four most informative ones were selected. The optimisation of the PCR conditions allowed the setting up of a powerful discriminative genotyping method. Moreover, the definition of a quality management method allowed definition of the key steps and the number of replicates to ensure reproducibility of the RAPD pattern. The RAPD was used to study the hot water network of a building. Legionella colonies (91) were isolated from seven locations and genotyped. The diversity of the population in one sample could vary from one to seven different strains. The study of the traceability showed that, in most of the cases, different populations could be present at different locations of the same network.
Cryptosporidium monitoring system at a water treatment plant, based on waterborne risk assessment
Authors: Masago Y. , Oguma K. , Katayama H. , Hirata T. , Ohgaki S.
Published: May 2018

The water volume required for daily monitoring of Cryptosporidium (which can statistically ensure an annual risk of infection below 10-4), was assessed by evaluating the applicability of the Poisson lognormal (PLN) distribution in microbial risk assessment. PLN showed as good a fit to the observed data as to the negative binomial distribution. From the estimated PLN distributions for the source and finished water, the efficacy of the oocyst removal by the conventional water treatment process was estimated to follow log-normal distribution (median = 3.16 log10, 95% CI = 4.27-2.05 log10). The 365 consecutive negative results of daily monitoring for 180 L of finished water were found to be statistically equivalent to the annual risk of infection below 10-4. This research also suggested the possibility of applying a qualitative detection method, such as CC-PCR, as a routine monitoring method for the quantitative risk management.