bluuebunny/crossref_metadata_2025 huggingface dataset:
The Occurrence of Cryptosporidium Spp. Oocysts in Scottish Waters, and the Development of a Fluorogenic Viability Assay for Individual Cryptosporidium spp. Oocysts
Authors: Smith H. V. , Grimason A. M. , Benton C. , Parker J. F. W.
Published: May 2018

A total of 262 water-related samples were analysed for the presence of Cryptosporidium spp. oocysts, of which 39.3% were positive, over a twelve month period. Similar data were obtained for their occurrence in samples of both raw and treated water from Scotland, with 40.5% of raw water and 40.1% of treated water being positive. Fewer oocysts were detected in the summer than in the autumn, winter or spring. In a 12 month survey of water used for abstraction, oocysts were detected at various times throughout the year in both raw and treated water. A series of conventional and fluorogenic dyes was used, in conjunction with a fluorescent labelled monoclonal antibody, in an attempt to assess their potential fox imprpving the identification of oocysts in water-related samples. In addition, preliminary data regarding the possible use of fluorogenic vital dyes as indicators of in vitro excystation and viability are presented.
Wastewater and Giardia Cysts
Authors: Gassmann L. , Schwartzbrod J.
Published: May 2018

Giardia intestinalis is a protozoon which has generated numerous waterborne outbreaks of giardiasis in the United States. In this study Giardia cysts were searched in raw wastewater after concentration by Bailenger method and quantification with Thoma cell counting. Different parameters were studied : sampling time, sampling day, sampling month. The study of hourly variations shows concentration of Giardia cysts ranged from 9.5 × 103 to 1.4 × 104/l with a significant difference between the samples taken at 10 a.m. and those taken in the afternoon. No significant daily variation has been shown in the mean value of the 6 samples taken every day. The results of monthly variations indicate that it is in February (5.9 × 103/l) and mainly in March (1.2 × 104/l) that the concentrations of the Giardia cysts are the highest. The lowest values are noticed in November (1.3 × 103/l).
Distribution of Giardia Cysts in Wastewater
Authors: Sykora Jan L. , Sorber Charles A. , Jakubowski Walter , Casson Leonard W. , Gavaghan Patrick D. , Shapiro Maurice A. , James Schott M.
Published: May 2018

This study was designed to determine geographic and seasonal distribution of Giardia cysts in wastewater and sludge and their removal by sewage treatment processes. Eleven wastewater treatment plants located in cities across the United States were included in the study. Flow weighted, composite samples of raw and treated wasteWaters and sludges were collected at monthly intervals for a period of one year. The cysts were concentrated by sucrose flotation or by simple centrifugation (“direct count”) and assayed microscopically.

Sucrose flotation counts of cysts in the raw sewage were extremely variable producing results ranging from 0.4% to 77.8% of the direct counts. Based on 12 consecutive months of sampling, and using the direct counts, the highest geometric mean Giardia cyst concentrations occurred at the California site (3375 cysts/L), the Florida site (3087 cysts/L) and the Vermont site (2040 cysts/L). The lowest geometric mean Giardia cyst levels were in samples from the Pennsylvania site (642 cysts/L), the Tennessee site (762 cysts/L) and the Maryland site (957 cysts/L). Cyst concentrations in raw sewage were highest in late summer, fall and early winter. Although all raw sewage samples contained cysts, only about one half of the wastewater treatment plant effluents were positive with cyst concentrations ranging up to 44 cysts/L. Based on sucrose flotation counts, the concentrations of cysts detected in the sludges ranged from 70 to 30,000 cysts/L.
A Review of the Epidemiology and Diagnosis of Waterborne Viral Infections
Authors: David Cubitt W.
Published: May 2018

A review of advances in our understanding of the significance of viruses as a cause of waterborne infections is presented. Emphasis is placed on problems associated with failures in water supply systems and the hazards of consuming raw or inadequately cooked molluscan shellfish. Recent developments in laboratory methods for the diagnosis of infections caused by the édiarrhoeal viruses are discussed and many papers cited for further reference.
Polyvalent Coliphages in Sewage
Authors: Qureshi Mahboob A. , Qureshi Ateef A.
Published: May 2018

High concentrations of coliphages were isolated during December and March when the maximum average daytime temperature reaches 20°C. Eight coliphages capable of infecting various strains of E. coli and a few selected members of Enterobacteriaceae were isolated. Although all polyvalent phages contained DNA, they showed variation in plaque size and heat sensitivity. These polyvalent phages may be exploited as a possible biological control of overwhelming populations of the coliforms and faecal coliforms in raw sewage prior to treatment.
Detection of Hepatitis a Virus and other Enteroviruses in Wastewater and Surface Water Samples by Gene Probe Assay
Authors: Dubrou S. , Kopecka H. , Lopez Pila J. M. , Maréchal J. , Prévot J.
Published: May 2018

Enteroviruses were specifically detected by dot blot hybridization when using poliovirus type 1 (PV1) derived subgenomic radiolabeled cRNA probes (riboprobes) in environmental water specimens and in the cell cultures in which the viruses were amplificated. The riboprobe corresponding to the 5' noncoding sequence detected the majority of enteroviruses. Hepatitis A virus (HAV) was specifically detected by an HAV cRNA probe corresponding to the 5' noncoding region of its genome. By this test, the limit of detection of coxsackievirus B5 and echovirus 7 seeded in mineral water was 103 to 104 PFU/spot. In cell cultures, positive signals were observed in the lysates of cells infected by one PFU. Higher positive signals were obtained with a short PV1 probe (nt 221-670) corresponding to the 5' noncoding region, which is a well preserved sequence among the enteroviruses, than with PV1 genomic probe. Hybridization allowed a good detection of enteroviral RNAs in wastewater specimens, but with a lower efficiency in surface water. In this case, amplification of viruses in the cell cultures gave significant hybridization results.
Growth of Clinical Isolates of Astro Virus in a Cell Line and the Preparation of Viral RNA
Authors: Wyn-Jones A. P. , Herring A. J.
Published: May 2018

Astroviruses from three sources, (1) of human origin, adapted to cell culture growth by passage in primary tissue and (2) direct from faeces; (3) of lamb origin, from gut epithelium scrapings were processed to extract the RNA. The first two of these were also compared in their growth on LLCMK2 and Caco-2 cell lines. Virus was successfully isolated direct from faeces in the latter line, though it failed to grow in LLCMK2. Previously adapted virus continued to grow well in both lines. RNA was extracted from the ovine virus in a condition which permitted the production of cDNA grior to cloning, but the RNA from the human astroviruses was more refractory to extraction owing to its aggregation with cell debris.
Behaviour of Pathogenic Bacteria, Phages and Viruses in Ground Water during Transport and Adsorption
Authors: Herbold-Paschke K. , Straub U. , Hahn T. , Teutsch G. , Botzenhart K.
Published: May 2018

In our study we investigated the transport and adsorption behaviour of different pathogenic microorganisms with two sorts of columns filled with quartz sand and aquifer material. These were the simian rotavirus SA 11, E. coli and the coliphages T4, MS2 and ϕX174. At a low filtration rate the breakthrough curves of the microorganisms show a wide distribution over a long period of time. When the filtration rate is increased the curves, sbow a, steep main peak. Only a small percentage of the microorganisms adsorbed to the quartz sand; in contrast, 53% of the SA 11 viruses adsorbed.
F-Specific RNA Bacteriophages as Model Viruses in UV Disinfection of Wastewater
Authors: Havelaar A. H. , Nieuwstad Th J. , Meulemans C. C. E. , van Olphen M.
Published: May 2018

F-specific RNA (FRNA) bacteriophages can be assayed in wastewater by simple and rapid methods. Their inactivation by UV radiation follows first-order kinetics and relatively simple formulas can describe the effect of UV absorbance by wastewater and the wavelength-dependent killing efficiency of polychromatic lamps. Because the organisms can be grown in high concentrations, biological calibration of full-scale reactors requires only relatively small volumes of phage culture. Naturally occurring FRNA-phages were more resistant to UV than somatic coliphages, Escherichiacoli and faecal streptococci. The inactivation rate constant was almost equal to that of reoviruses, which underlines the suitability of FRNA-phages as a process indicator for UV inactivation of viruses. A pure culture of MS2 was inactivated at a rate which was almost twice that of naturally occurring FRNA-phages, indicating the necessity of designing reactors for practical applications on field-data rather than laboratory experiments.
The Activity of Peracetic Acid on Sewage Indicator Bacteria and Viruses
Authors: Baldry M. G. C. , French M. S. , Slater D.
Published: May 2018

The increasing use of products containing peracetic acid for the disinfection of sewage and effluents has produced a demand for information about the activity of PAA against relevant microorganisms. Studies have therefore taken place to establish the comparative effects of peracetic acid and chlorine on both bacteria and viruses. Peracetic acid has previously been shown to be active against faecal indicator bacteria Recent laboratory studies have established that peracetic acid is also an effective agent against viruses typical of those found in sewage. This activity is maintained even in experimental systems containing high levels of organic matter such as yeast extract. In contrast, although sodium hypochlorite is an effective virucide in clean experimental systems, the presence of organic matter greatly increases the level of added available chlorine necessary to achieve a given level of viral inactivation.
Comparative Study on Adsorption Mechanisms of RNA-F-Specific Coliphages and Poliovirus in Activated Sludge Process
Authors: Ketratanakul A. , Ohgaki S. , Yano K.
Published: May 2018

The adsorption mechanism of RNA-F-specific coliphages, Qβ, and poliovirus 1 in the activated sludge process was studied experimentally. The mechanisms of Qβ and poliovirus associated with microbial flocs were attributable to the pH change in the system which was caused by either microbial activity during glucose uptake or the added acids/alkalis. The adsorption mechanisms of them seemed to be similar, and the only difference was the pI level of each other. In addition, Qβwas found to be more tolerant of environmental stress than was the case for poliovirus because of Qβ being stable for a week in a batch activated sludge reactor. By contrast, poliovirus was reduced about 0.8 log in three days in the identical reactor.
Detoxification by Sephadex LH20 of Seafood Concentrates for Rotavirus Assay
Authors: Beril C. , Boher S. , Schwartzbrod L.
Published: May 2018

Virological analysis of seafood is often limited because of the toxic effects of the mollusc concentrates on cell cultures. We have developed a method of detoxification based on filtration through a Sephadex LH20 gel. Results show that in mussels concentrates after filtration the toxicity has decreased in a factor between 4 and 10 in 79 % of cases. With oysters the toxicity has decreased in a factor between 4 and 10 in 55 % of concentrates. Virus were recovered from 10 % mussels concentrates after filtration while no virus were recovered from crude concentrates before filtration. LH20 Sephadex filtration appears to be a simple method for decreasing shellfish tissues toxicity for cell cultures.
Comparison of Two Methods for the Recovery of Rotavirus from Mussels and Oysters
Authors: Boher S. , Beril C. , Terver D. , Schwartzbrod L.
Published: May 2018

Two extraction-concentration methods for recovering rotavirus from mussels and oysters are compared. Molluscs are artificially contaminated by a one hour stay in seawater seeded with rotavirus SA 11. Results show that the first procedure using a glycine-NaCl pH 10 solution and an organic flocculation gives quite similar virus recovery from mussels and oysters, whatever the quantities of rotavirus in seawater are. The second procedure using a borate buffer - 3 % beef extract pH 9 and a double precipitation with Polyethylene glycol 6000 leads in most cases to a more efficient virus recovery, based on immunofluorescent foci counts on cover slip cultures of MA 104.
Activated sludge plant facing grape harvest period – a case study
Authors: Chudoba P. , Pujol R.
Published: May 2018

Most of municipal activated sludge plants located in wine production regions receive winery wastewaters during the grape harvest period which lasts usually only a few weeks. A drastic increase in organic pollution (COD, BOD) during this period generates a temporary overloading, resulting very often in biological problems such as decreased sludge settleability, sludge floc disintegration, increased SS concentration in treated effluent and in the worst case a complete plant failure. In order to work satisfactorily even during those temporary overloading periods, the plant has to be oversized. This strategy is rather costly, because such a plant has to run below its nominal capacity during a major part of the year. An original solution has been proposed and successfully tested at a municipal wastewater treatment plant in Eguisheim, France. The proposed technique is based on the addition of a mineral material with a low particle size, whose presence positively influences the physical behaviour of the sludge and will allow the nominal capacity of the plant to be surpassed without any important modification. The modification of the sludge structure around the added powdered material improved significantly the sludge settleability (DSVI< 160 ml/g) and enabled the plant to treat organic pollution several times higher than the nominal level.
Anaerobic codigestion of agricultural industries' wastewaters
Authors: Gavala H. N. , Skiadas I.V. , Bozinis Nikolaos A. , Lyberatos G.
Published: May 2018

Wastewaters generated from agricultural industries are usually hard to treat due to a high organic content. The basic treatment process to be used can only be anaerobic digestion, a process with the additional advantages of (i) limited production of stabilized sludge and (ii) utilization of the produced biogas. The cotreatment of such seasonally produced wastewaters is proposed in order to secure the economically favorable and stable year-round operation of a treatment plant, with the additional benefits of smaller capital costs (due to the use of centrally located rather than distributed treatment facilities) and the exploitation of complementarity in waste characteristics (e.g. avoidance of nutrients (N,P) addition when a codigested wastewater contains nutrients in excess). A mathematical model for codigesting piggery, olive-mill and dairy wastewaters was developed based on batch kinetic experiments. An organic loading rate of 3.84 g COD/l·d was found to be safe for a digester operating on a year-round basis, fed sequentially with piggery, piggery-olive-mill and piggery-dairy wastewaters.
A field treatment plant for pig slurry
Authors: Martinez José , Hao Xiaodi
Published: May 2018

The SOLEPUR process for the treatment of pig slurry, based on the treatment effect of the soil, was developed in France to explore the notion that a simple biobarrier approach may be a potential efficient solution to the large accumulation of liquid animal wastes residues. The unit consists of (i) a managed field (3280 m2) which allows the total recovery of all the leachate water which percolates through growing ryegrass (Lolium perenne), to which the pig slurry is applied, (ii) a system of storage-pump-reactor for denitrification and (iii) a non-managed field for completing treatment. The process involves three operations: (1) overdosing the managed field with surplus slurry (about 1000 m3 pig slurry/ha.year applied from 1991 to 1994), (2) collecting and treating the nitrate-rich leachate and (3) irrigating the final treated water over other fields. This process decreased COD of pig slurry by 99.9 % and removed 99.9 % of phosphorus and approximately 80 % of nitrogen. The remaining nitrogen was oxidized in the soil into nitrate and leached out in the drainage water. The process of denitrification was selected to remove nitrate from the leachate and raw pig slurry was used as an external carbon source.
Coliform die-off rate constants in a high rate algal pond and the effect of operational and environmental variables
Authors: Fallowfield H. J. , Cromar N. J. , Evison L. M.
Published: May 2018

High rate algal ponds (HRAPs) are an adaptation of waste stabilisation ponds, in which increased treatment efficiency and reduced pond area are achieved by optimising conditions for algal photosynthetic oxygen production. If the treated effluent is subsequently to be reused for irrigation of crops and recreational areas, from a public health viewpoint it is important to reduce the risk of contamination by pathogenic organisms. The microbiological quality of effluents is traditionally assessed by enumerating the coliform group of organisms. Die-off rate constants (Kb) of 0.35 − 2.34 d−1 were measured for E.coli in outdoor ponds operating on synthetic sewage mix with acetate as the carbon source (260 kg COD ha−1 d−1) at a range of depths from 12 to 34 cm. There were significant positive effects of pH, irradiance and pond depth on Kb. Light penetration throughout the pond depth was calculated and shown to be a useful parameter for the prediction of Kb. Multiple regression equations describing the influence of these environmental parameters on die-off rate constant were derived. Dry matter concentration negatively affected light penetration but had a positive influence upon pH. Pond operating conditions to maximise E.coli die-off are discussed.
Ion exchange and adsorption of some heavy metals in a modified coconut coir cation exchanger
Authors: Baes A. U. , Umali S. J. P. , Mercado R. L.
Published: May 2018

Potentiometric titration experiments were carried out to determine the relative ability of sodium and different heavy metal cations in replacing protons from ionogenic sites of a modified coconut coir cation exchanger. The relative preference for the cations follow the sequence: Na ≪ Ca(II) < Mn(II) < Ni(II) < Cu (II) < Pb(II). This preferential series was confirmed by determining the concentrations of the divalent cations and sodium which were adsorbed by the material during the titration process. Adsorption isotherms at pH 4 and pH 6 were obtained to determine the Langmuir adsorption constants for the heavy metal cations. The adsorbent material adsorbed high amounts of Pb(II), Cu(II) and Ni(II) (in decreasing order) from solutions whose concentrations were comparable to those of wastewaters. Our results show that the modified coconut coir cation exchanger has good potential as an adsorbent of heavy metals in industrial wastewaters.
Strategies for pollution control in tanneries located in Minas Gerais State, Brazil case study
Authors: Chernicharo C. A. L. , van Vliet M.
Published: May 2018

This paper presents the planning and initial results of an environmental project for pollution control in tanneries located in Minas Gerais State, Brazil. The planning comprises three phases: i) diagnosis of the industrial sector, ii) training of human resources, and iii) technological development. The project has an estimated cost of US $220,000, and it is being developed by the Department of Sanitary and Environmental Engineering of the Federal University of Minas Gerais, in cooperation with representatives of the industrial and environmental sectors. The project is also supported by the German Agency GTZ (Deutsche Gesellschaft für Technische Zusammenarbeit).

The first results indicated that the project is achieving its aims of getting to know the situation and helping to solve the problems related to the tannery industry. Furthermore, the structure of the project, based on the participation of representatives of the various institutions concerned with the productive and environmental sectors, has shown to be a good start of a joint mobilization.
Wastewater reclamation and reuse in Japan: overview and implementation examples
Authors: Asano T. , Maeda M. , Takaki M.
Published: May 2018

To alleviate potentially catastrophic water supply and wastewater disposal problems as well as expand dependable water supply infrastructure, Japan has launched comprehensive urban wastewater reclamation and reuse projects since 1968. In this paper, the status of national policies on wastewater treatment, wastewater reuse characteristics, and some wastewater reuse experiences are presented. Two implementation examples in Tokyo and Fukuoka are discussed in detail, with special reference to application for toilet-flushing in high-rise business buildings and stream restoration and flow augmentation. It was found that the key to the success of wastewater reclamation and reuse is the quality of reclaimed water; public acceptance is closely associated with water quality and water supply dependability.
Groundwater recharge with municipal effluent: Dan Region Reclamation Project, Israel
Authors: Kanarek A. , Michail M.
Published: May 2018

The Dan Region Project is the largest water reclamation scheme in Israel which provides for collection, treatment, groundwater recharge and reuse of municipal wastewater from Tel-Aviv metropolitan area and several other neighboring municipalities. The project serves a total population of about 1.3 million with an average municipal wastewater flow of 270,000 cu.m/d.

The special recharge-recovery method developed and practiced successfully in the Dan Region Project is rather a soil aquifer treatment (SAT) which should be considered as an integral part of the municipal wastewater treatment process. SAT consists of controlled passage of effluent through the unsaturated zone and the aquifer, mainly for purification purposes, as well as for seasonal and multiannual storage. The recharge operation is carried out by means of spreading basins which are surrounding by adequately spaced recovery wells which permit separating the recharge zone from the rest of the aquifer.

The major purification processes occurring in the soil aquifer system are: slow-sand filtration, chemical precipitation, adsorption, ion exchange, biological degradation, nitrification, denitrification and disinfection. Water quality control in the recharge zone is virtually complete and the very high quality of reclaimed water obtained after SAT is suitable for a variety of non potable uses especially for unrestricted agricultural irrigation. During the last five years, about 400 million cu.m of reclaimed water was supplied for unrestricted irrigation to the south of the country.
Soil as a complementary treatment component for simultaneous wastewater disposal and reuse
Authors: Oron Gideon
Published: May 2018

Field experiments were conducted to verify the hypothesis that soil performs as a complementary biofilter for secondary domestic treated wastewater disposal. The soil surrounding a subsurface point source functions as a biofilter for effluent used in agricultural irrigation. This hypothesis was examined in an outdoor experiment in which poliovirus was injected into the subsurface drip irrigation system. According the results, high virus concentration in applied effluent resulted in a very limited penetration into tomato plants via the roots. However, no viruses were detected in the leaves and the fruits.
Use of computers for process design analysis and control: sequencing batch reactor application
Authors: Brenner Asher
Published: May 2018

Computers have become a vital part of every modern wastewater treatment plant. They can be used for design, analysis, and control of the treatment process. Mathematical modelling and simulation of various process configurations, load conditions, and operational strategies lead to better understanding and improved design and operation. Computer assisted analysis of process performance and automatic control of plant units aid reduce expenses related to energy, chemicals, and man power. Stringent disposal constraints imposed in most modern countries require application of sophisticated computerized control systems to ensure high quality effluents. The sequencing batch reactor system is similar to the conventional activated sludge process in its ability to achieve biological removal of organic carbon and nutrients by a single sludge. However, due to the non-steady-state nature of the process, and to the large substrate and nutrient gradients occurring during the operating cycle, some modifications in the traditional activated sludge waste characterization and process modelling should be considered.
Experimental validation of a simulation and design model for nitrogen removal in sequencing batch reactors
Authors: Andreottola G. , Bortone G. , Tilche A.
Published: May 2018

The development and the sensitivity analysis of a dynamic SBR simulation model for biological nitrogen removal, based on the Activated Sludge Model N. 1, are presented. An experimental study for the calibration and validation of the model was carried out using a bench scale SBR. Piggery wastewater was used as feed. The operating daily cycle of the SBR reactor included three sub-cycles of 7.5 hours each, each one alternating anoxic and aerobic condition, while settling phase was carried out at the end of the three sub-cycles.

A first enhancement of model N. 1 was performed splitting nitrification into the two sub-processes of nitriation and nitratation. A second enhancement of the model was obtained with the introduction of a switch function of nitratation kinetics.

An algorithm for optimization of the cycle length and phase distribution in order to minimize effluent nitrogen concentration was developed. A design procedure of SBR systems is also described.
Pilot plant performance and model calibration of a sequencing batch air-lift reactor
Authors: Brenner A. , Ben-Shushan N. , Siegel M. H. , Merchuk J. C.
Published: May 2018

A sequencing batch wastewater treatment process was studied in a 200 L air-lift reactor (ALR), using a synthetic wastewater. A modification of the SBR process was introduced to exploit the ALR's geometric structure using an upflow anaerobic sludge blanket (UASB) mode of feeding. The mean COD removal efficiency of the process was extremely high. A study was made of the change in the filtered COD concentration in the reactor as a function of time during a cycle. A partial reduction in the COD was observed after the UASB Fill stage. Further removal of the residual COD was achieved within a very short time once air was supplied to the system. These phenomena required the inclusion of a biosorption-storage concept in the mathematical description of the system, in order to predict more precisely the COD transformations. The mathematical model parameters were evaluated experimentally and then calibrated with the aid of an optimization technique. Experimental results including COD, MLVSS, DO and OUR changes showed good agreement with model predictions.
Biological phosphorus removal with different organic substrates in an anaerobic/aerobic sequencing batch reactor
Authors: Carucci A. , Majone M. , Ramadori R. , Rossetti S.
Published: May 2018

Experimental work was carried out with a lab-scale SBR, whose operation was divided into three runs: I run (glucose + acetate feed, 3′ fill), II run (only glucose feed, 3′ fill), III run (only glucose feed, 60′ fill). The results show that the bacteria growing in alternating anaerobic/aerobic systems can remove organic substrates under anaerobic conditions even without using the hydrolysis of polyphosphates or the transformation of glycogen into poly-hydroxyalkanoates as the energy sources for the uptake and storage of substrate. However, in the case of acetate plus glucose feed, EBPR can be steadily established with typical PP-bacteria like metabolism even if most of the COD removal takes place under not truly anaerobic conditions.
Activated carbon sequencing batch biofilm reactor to treat industrial wastewater
Authors: Kolb Frank R. , Wilderer Peter A.
Published: May 2018

In many cases, components of industrial process wastewaters are non-readily biodegradable, but can be effectively removed from the wastewaters by means of adsorption processes to activated carbon (AC). However, the loading capacity of an AC filter is often low and the endurance of the adsorber packing is short. The loaded AC must eventually be thermally regenerated and/or deposited. The costs for spent AC regeneration and disposal are significant. Biological in situ regeneration of AC to prolong the endurance of the adsorber and to reduce operating expenses appears to be an interesting option. Combination of AC adsorption and biodegradation may provide additional advantages. For instance, the bulk liquid concentration of critical wastewater components is decreased by adsorption so that inhibitory effects on the bacteria are damped or may even disappear. Volatile organics may be kept available to the bacteria instead of being stripped. To investigate the potentials of this process concept, an experimental loop reactor system was designed consisting of an AC packing, and a membrane mass transfer module. The reactor system was operated as a Sequencing Batch Reactor (SBR). Mixtures of benzene/2-chlorophenol and trichloroethene/phenol were used to make up model wastewaters. The hydrodynamic conditions and the bio-regeneration strategy was systematically varied during the investigations. The results obtained show that the endurance of the AC can be prolonged by at least five times value of a merely physically operated adsorber. Benzene/2-chlorophenol could be biodegraded by almost 95 per cent during a 24 hour cycle. Of the trichloroethene added per cycle about 5 per cent was degraded. Consecutive process operation (loading of the AC followed by bio-regeneration) led to higher degradation rates than simultaneous operation (loading and regeneration at the same time).
Co-current nitrification/denitrification and biological p-removal in cyclic activated sludge plants by redox controlled cycle operation
Authors: Demoulin Gunnar , Goronszy Mervyn C. , Wutscher Konrad , Forsthuber Egbert
Published: May 2018

Several variations of SBR processes are reported in the literature; one of these uses the acronym CAST, Cyclic Activated Sludge Technology, and has been developed specifically for large-scale domestic wastewater treatment application (20,000 to 400,000 P.E.). This process was used to relieve existing overload conditions at the Groβarl WWTP which treats sewage from a ski resort using a conventional nitrifying/denitrifying (N/DN) process. The efficacy of the conventional and cyclic processes were compared through parallel operation over a one year period. Through examination and comparison of the nitrification rates, the stability of co-current nitrification/denitrification and the biological phosphorus removal it was found that the cyclic system was demonstrably superior in treatment efficiency when operated at the same loading conditions as the conventional process. Nitrification rates were about 35 percent higher in the cyclic system. Phosphorus elimination was about 83 per cent in the cyclic system and 55 per cent in the conventional system at the same loading conditions. Applying the results of the design criteria used for the cyclic system, a volumetric saving of about 30 per cent compared to the use of conventional treatment technology is obtainable for the proposed full-scale amplification. The optimization strategy of selecting set-point dissolved oxygen concentration in the basins according to the on-line measured oxidation reduction potential (ORP) and its rate of change throughout a cycle proved to be a valuable tool for optimizing nitrogen and phosphorus removal.
Winery wastewater depollution by sequencing batch reactor
Authors: Torrijos Michel , Moletta René
Published: May 2018

The aim of this study was to demonstrate a depollution process for the treatment of the effluents of small wineries, producing less than 15,000 hl of wine per year. Given the particular characteristics of wine effluents and, in particular, the seasonal nature of the discharges, the best solution was found to be a sequencing batch reactor (SBR) fed once a day, and equipped with upstream temporary storage facilities acting as a buffer.

The performance of this process for the depollution of winery wastewater were studied during the 1994 grape harvest in a winery producing 7,300 hectolitres annually. The results obtained (93% of elimination for total COD; 95% for soluble COD; 97.5% for BOD5), as well as the simplified automation, the low capital cost and the moderate operating costs, show that the process is well suited to depolluting wastewater from small wineries.
Opening speech of the 11th Stockholm Water Symposium
Authors: Skogfors Sven-Erik
Published: May 2018

Eleven years have now passed since the Stockholm Water Company took the initiative to establish the Stockholm Water Symposium. Since then our water conference has taken place each August here in Stockholm and, step by step, has increased its role to serve as the meeting point for leading actors in the water field. The Symposium has also become a core activity in the series of water events we call the World Water Week in Stockholm.
Evangelizing in the media age: American and Swedish perspectives on how to spread your message
Authors: Wästberg Olle
Published: May 2018

Political decision making is influenced by a complex interaction between politicians, their constituents, lobbying groups and the media. Water professionals, scientists and campaigners, who wish to evangelise, to bring the critical issues of the water environment to the centre of public attention and achieve changes in society must understand the evolving symbiosis between politicians and the media.
Water challenges for the 21st century
Authors: Coulomb René
Published: May 2018

The World Water Council was created in to act as the international water policy think-tank and can thus play a central role in defining the water challenges for the 21st century and the routes to their solution. This article outlines the origins of the Council and the major steps undertaken since its foundation in 1996, inluding contributions to the various World Water Forums, the World Water Vision and other agenda-setting international meetings.
Water and energy linkages for groundwater exploitation: a case study of Gujarat State, India
Authors: Gupta Rajiv K.
Published: May 2018

Water and energy, two important resources for human development, have inextricable inter-linkages between them. Their complementarity, a blessing otherwise, causes a vicious cycle in a complex situation like the present case study of Gujarat State, India. This paper analyses the demand-supply situation of both sectors for a State that is primarily agrarian but also with a high industrial growth rate. Due to inequitable distribution of surface water, recurrent droughts and ever increasing demand trend, groundwater (a major source in the State) has been overexploited in many parts, leading to ‘water mining’ with worsening water quality. With more than 40% energy consumed for extracting groundwater, this has had a serious impact on the energy balance. The paper discusses the energy requirements to satisfy the water needs and the water requirements for generation of energy. Finally, the feasible options available to meet the crisis, ranging from development of mega projects like Sardar Sarovar and Kalpasar to micro water harvesting structures, water pricing, consumer training etc., are reviewed.
Workshop 5 (synthesis): dams, environment and regional development
Authors: Söderbaum Peter
Published: May 2018

Dams are controversial: their positive results include electricity generation, flood control, and irrigation; negative effects include population displacement and ecological impacts. A fair assessment can only be made on a case by case basis, judging individual projects in their individual context, and using holistic and interdisciplinary approaches. Decisions can no longer be taken purely on technical considerations, ethical issues must be incorporated into the decision-making process. The report of the World Commission on Dams was recognised as a significant move in the right direction.
Muddy perceptions/dirty water: messages for clearing the visions of the public and the powerful
Authors: Ross Steven S.
Published: May 2018

Globalism does not usually work when it comes to spreading the word about water! There is no one formula for explaining water issues to the public or to public officials. Sometimes you should go to reporters. Sometimes you should focus on educating editors. Sometimes you concentrate on educating teachers, sometimes the business community, bureaucrats or elected officials. Sometimes your message concentrates on fisheries, sometimes health, sometimes tourism. Often, you will want to emphasize something else – even sales of genetic material that might be dependent on biodiversity. In short, your message must be adapted to the local circumstance. Your methodology will depend on whether you must stimulate immediate action, or whether you have the luxury of pushing a longer-term message. The Web opens many new possibilities. Cost of Web distribution is low. The Web offers a combination of many effective storytelling tools such as audio, video, and animation. Multi-lingual materials are easier to prepare than for film. But at this stage of Web development it may be more efficient to provide material to existing publications' Web sites and to NGOs and official sites, than to establish special stand-alone Web sites. I propose a “resource” Web site for those who have responsibility for water projects. The site would contain articles and explanatory material provided by media organizations, attracted by a modest contest-and-prize system.
Opening speech of the 13th Stockholm Water Symposium
Authors: Berntell A.
Published: May 2018

The World Water Week in Stockholm is the only annual water meeting with such broad participation from different sectors of society, water professionals, technicians, scientists, policy makers, private sector actors, NGOs and many other stakeholders. This is what makes our week unique, your participation, and that is why we can offer such an interesting programme and such excellent opportunities for constructive dialogue. Building bridges through dialogue between different interest groups is a key goal that we increasingly feel that we are achieving.
Drainage basin security - a key to reaching the water-related Millennium Development Goals
Authors: Børge Brende H.E.
Published: May 2018

“We don't realize the value of water until the well is dry”, Benjamin Franklin once said. This statement captures in many ways the water development and management challenges we are faced with. The value of water to humans and nature is not properly recognized. The role of water as an engine for growth and the macro-economic impacts of poor water management and water resources degradation are largely unknown.
Symposium conclusions and reflections
Authors: Falkenmark M.
Published: May 2018

The Symposium had its focus on Drainage Basin Security - Balancing Production, Trade and Water Use. A whole set of different perspectives were addressed. The Chair of the Scientific Program Committee, Professor Malin Falkenmark, summarizes some conclusions that can be drawn and adds some personal reflections.
Virtual water flows and trade liberalization
Authors: Ramirez-Vallejo J. , Rogers P.
Published: May 2018

The linkages between agricultural trade and water resources need to be identified and analyzed to better understand the potential impacts that a full liberalization, or lack thereof, will have on water resources. This paper examines trade of virtual water embodied in agricultural products for most countries of the world. The main purpose of the paper, however, is to examine the impact of trade liberalization on virtual-water trade in the future. Based on a simulation of global agricultural trade, a scenario of full liberalization of agriculture was used to assess the net effect of virtual water flows from the relocation of meat and cereals’ trade. The paper also identifies the main reasons behind the changes in the magnitude and direction of the net virtual water trade over time, and shows that virtual water trade flows are independent of water resource endowments, contrary to what the Heckscher-Ohlin Theorem states. Finally, based on a formal model, some input demand functions at the country level are estimated. The estimates of the income and agricultural support elasticities of demand for import of virtual water have the expected sign, and are statistically significant. Variables found to have some explanatory power of the variance of virtual water imports are average income; population; agriculture as value added; irrigated area, and exports of goods and services.
Forests and water - closing the gap between public and science perceptions
Authors: Calder I.R.
Published: May 2018

The public perception that forests are, in all circumstances, necessarily good for the water environment, that they increase rainfall, increase runoff, regulate flows, reduce erosion, reduce floods, “sterilize” water supplies and improve water quality, has long been questioned by the scientific community. The evolving “modern” science perception suggests a more complex and generally less advantageous view of forests. It is suggested that the disparity between the two perceptions needs to be addressed before we are in a position to devise and develop land and water policies which are aimed at either improving the water environment, and by doing so improving the livelihoods of poor people by greater access to water, or conserving and protecting forests. Examples are given of “interactive” research projects in different parts of the world including the UK, South Africa, Panama and India where, through the involvement of stakeholder groups, often with representatives comprising both the science and public perceptions, research programmes have been designed and are being implemented, not only to derive new research findings with regard to the biophysical processes, but also to achieve better “ownership” and acceptance of these research findings by the stakeholder groups.
Growing controversy over “wise international water governance”
Authors: Trondalen J.M.
Published: May 2018

This article takes the perspective that when political relationships are strained, there seem to be few examples of wise international water resources governance. The Middle East is a striking example. Much effort has been put into policy development and the design of international principles, but very little into the translation of those into concrete and lasting governance. One of the theses of the article is that politics - whether domestic or international- in most cases overrides these principles and standards. Moreover ready-made regional co-operation models of water managements are not directly applicable to every geographical, political, economic and social setting. Certain factors are often under-estimated in international water negotiations, such as:• the complexity of any hydro-political negotiations, and need to develop commonly accepted standards;• the difficulty of translating policy - either politically or legally - into an operational and realistic negotiations strategy;• the format of the procedures and meetings;• recognition that third parties should have a long-term perspective on any conflict they get involved in.With reservations, the lessons learned indicate that the following factors have an impact on grid locked situations, such as: new substantive information; new trade-offs between the parties; and changed political climate or relationship with external power-brokers.
Meeting everyday water needs - a company's contribution
Authors: Duncan D.
Published: May 2018

As a packaged consumer goods company serving mass markets around the world for household and personal hygiene products, laundry detergents and foods, Unilever's business is inextricably linked with consumers’ interest in meeting their everyday water needs. Once the basic need for drinking water is met, almost all other “everyday” water needs derive from consumption associated with the type of products Unilever sells. Use of some of these products, such as basic toilet soap, involve “actual” water consumption; others, such as margarine, concern “virtual” water consumption through agricultural production.

Global scenarios for water and sanitation present a major challenge to long-term business strategies that assume sustained economic growth particularly in emerging and developing markets. Responsibility for finding and delivering solutions lies with all major actors in society. For companies such as Unilever, a priority is to help break the link between economic development on the one hand, and increased water use and water degradation on the other. Water catchment level perspectives are central to realising this vision. Unilever uses such a framework, building an experience-based model that demonstrates how a “consumer” company can engage in meeting everyday water needs with a sustained positive impact.
Strategies to manage stream flow to benefit people and nature: a non-government conservation organisation's perspective
Authors: Pittock J. , Holland R.
Published: May 2018

More than for any other biome, freshwater biodiversity is increasingly imperiled, particularly due to poor stream flow management and increasing demand for water diversions. The adoption by the world's governments of targets to extend water services to the poor and at the same time to conserve biodiversity increase the need to better direct investments in freshwater management. In this paper WWF draws on examples from its work to identify areas where investment can be focused to assure efficient water use and improve stream flow management, namely:• Prioritize and target those river basins and sub-catchments that are most critical for conservation of freshwater biodiversity to maintain stream flows;• Link strategic field, policy and market interventions at different scales in river basins to maximize the impact of interventions;• Implement the World Commission on Dams guidelines to minimize investment in large scale and costly infrastructure projects;• Apply market mechanisms and incentives for more sustainable production of the world's most water consuming crops;• Enhance statutory river basin management organizations to draw on their regulatory and financial powers;• Implement international agreements, such as the Convention on Wetlands;• Integrate environment and development policies.
Drainage basin management, local action plans and national policy: the perspective of the European Framework Directive
Authors: Ollén J.
Published: May 2018

The EC Water Framework Directive requires that all Member States achieve “good water status” by 2015 for both surface water and groundwater. The procedures by which Sweden intends to implement the Framework Directive are described and involve the establishment of five water districts, each with a water authority; local cooperative bodies based on the main river basin areas; cooperative associations for water conservation; introduction of a system of charges for water conservation; and assigning responsibility for supervision of contingency measures to the water authorities.