bluuebunny/crossref_metadata_2025 huggingface dataset:
Two approaches to indirect potable reuse using membrane technology
Authors: Lozier J.
Published: May 2018

A pilot study was conducted at McAllen, Texas to evaluate two microfiltration technologies, Memcor and ZeeWeed, to treat secondary effluent from the city of McAllen south WWTP. The objectives of the study were to compare the ability of Memcor and ZeeWeed to pretreat secondary effluent for subsequent processing by RO and to evaluate the ability of the ZenoGem membrane bioreactor process to directly treat screened, de-gritted wastewater to a quality suitable for direct processing by RO.

The results showed both Memcor and ZeeWeed to be competitive in their ability to produce a high quality filtrate from secondary effluent. The results also indicated that the ZenoGem process is capable of producing a filtrate suitable for RO treatment while meeting the City's current wastewater effluent discharge requirements. Additionally, the ZenoGem treated McAllen's raw wastewater to a quality comparable to the city's existing WWTP effluent.
Relationships between bacteria and cyanobacteria in the Marrakech waste stabilisation ponds
Authors: Oufdou K. , Mezrioui N. , Oudra B. , Barakate M. , Loudiki M. , Ait Alla A.
Published: May 2018

In waste stabilisation pond systems the interactions between algae and bacteria have an important ecological effect and appeared to play a key role in the self-purification process. The aim of the present study is to evaluate the interactions between two axenic cyanobacteria: Synechocystis sp. and Pseudanabaena sp. with heterotrophic bacteria and some pathogenic bacteria: E. coli, Salmonella sp. and non-O1 V. cholerae. The results obtained showed that Synechocystis sp. (planktonic cyanobacterium) and Pseudanabaena sp. (benthic cyanobacterium) stimulated the growth and the survival of heterotrophic bacteria and non-O1 V. cholerae and reduced the survival of E. coli and Salmonella. Blooms of these cyanobacteria during hot periods which are a particularity in stabilisation ponds of Marrakech, could explain the dynamics of bacteria studied in this sewage treatment process. The presence of heterotrophic bacteria, showing relative high densities during hot periods, could be considered as an important bioticfactor which led to the cyanobacteria blooms in the Marrakech ponds which function under an arid Mediterranean climate.
Tertiary treatment of piggery wastes in water hyacinth ponds
Authors: Costa R. H. , Bavaresco A. S. , Medri W. , Philippi L. S.
Published: May 2018

This work was developed in two stages: initially in water hyacinth ponds under batch conditions (pilot-scale) and later in full-scale ponds under a continuous state, so as to determine local parameters for the operation of this kind of pond for piggery wastes treatment. Seasonal variations are important features influencing plant productivity and performance. The water hyacinth ponds were able to remove around 50% of the applied organic loads (COD, BOD, TN, TP), even in case of elevated values (110 kg/ha/day) applied for total nitrogen surface loads. An hydraulic retention time of 20 days was shown to be ideal for the treatment. The utilization of water hyacinths as a complement for the animal diet closes the productive cycle in a sustainable way. The results have demonstrated the feasibility of the proposed treatment system.
Attenuation of microorganisms in the soil during drip irrigation with waste stabilization pond effluent
Authors: Campos C. , Oron G. , Salgot M. , Gillerman L. , Casais G.
Published: May 2018

Waste stabilization ponds (WSP) are one of the most appropriate wastewater treatment methods to reduce nematode and faecal coliforms. However, there is still a risk of contamination of crops and soil irrigated with this kind of effluent. The purpose of this work was to examine the fate of microorganisms (faecal coliforms, F+, and somatic coliphages and helminth eggs), from WSP effluent used for irrigation of a vineyard orchard, under onsurface (ODI) and subsurface drip (SDI) systems. The field is located near the City of Arad (Israel). The soil and water samples were taken during the irrigation periods of two consecutive years (1997 and1998). During the first year the vineyard was irrigated with a low quality effluent from WSP (sedimentation and maturation ponds only) and during the second year a high quality effluent (sedimentation, anaerobic, and a series of aerobic ponds and a final reservoir) was used. The results showed a substantial elimination of microorganisms in the soil, decreasing negative impacts, and minimising environmental and health risks.
Informal fish culture in the Maracanaú waste stabilisation ponds in Fortaleza, Brazil
Authors: da Silva F. J. , Mara D. D. , Pearson H. W. , Mota S. E.
Published: May 2018

The Maracanaú WSP in Fortaleza, the largest pond system in northeast Brazil, treating combined domestic and industrial (mainly textile) wastewater, was studied during a 13 month period. BOD and COD removal was 93 and 84%, respectively. On average the algal biomass represented 58% of total BOD in the ponds (3.3 mg per 100 μg of chlorophyll a). Ammonia removal was high (95%) but phosphorus was poor (20%). Faecal coliform removal reached 6 log10 units and the count in the final effluent was ≤1,000 cells/100 ml. This performance was expected since the hydraulic retention time was greater than 100 days. Informal fish culture of Nile tilapia (Oreochromis niloticus) was practised by local fishermen in the secondary and tertiary maturation ponds with yields of 1,706 and 241 kg/ha, year, respectively. Capture per unit efforts (CPUE) were similar to those found in local inland fisheries. However fish biometry showed a poorly attractive product for commercial purposes, with mean individual fish weights of less than 100 g.
EU policy on nutrients emissions: legislation and implementation
Authors: Blöch H.
Published: May 2018

After 25 years of EU water legislation the European Union has just thoroughly restructured its water policy. The European Parliament and the Council, following a tough conciliation procedure between the two legislators, have in summer 2000 agreed a proposal by the European Commission for a Water Framework Directive. This legislation will have the following main objectives:integrated river basin management across borders, with coordinated programmes of measuresprotection of all waters, surface waters and groundwater, in quality and quantity with a proper ecological dimensionemissions and discharges controlled by a “combined approach” of emission limit values and quality standards, plus the phasing out of particularly hazardous substancesintroducing water pricing policiesstrengthening public participation

This new Water Framework Directive adopted in September 2000 will complement existing EU water legislation on nutrients reduction - the 1991 Directive on nitrates pollution from agricultural sources and the 1991 Directive on urban waste water treatment. These Directives will remain main pillars of EU water policy whilst at the same time being integrated into the river basin management in a coherent way.
The characteristics of phosphorus removal in an anaerobic/aerobic sequential batch biofilter reactor
Authors: Chiou R. J. , Ouyang C. F. , Lin K. H. , Chuang S. H.
Published: May 2018

Previous research has shown that alternated anaerobic/aerobic conditions are effective in removing phosphorus from wastewater using a biofilter system. However, few studies have been conducted on the features of polyphosphate (poly-P) accumulating organisms (PAOs) in biofilm on phosphorus removal. This study investigated the characteristics of the phosphorus removal mechanism in various hydraulic loads and anaerobic/aerobic time ratios using a sequential batch biofilter reactor. The storage and release of intracellular inclusions, especially polyhydroxyalkanoates (PHAs) and poly-P, would be an important factor for phosphorus removal. Under different operating conditions, total phosphorus removal was always determined by accumulation of PHAs and phosphorus release under the anaerobic phase. The PHA accumulation under the anaerobic phase was always in proportion to the biofilm phosphorus content under aerobic conditions. The result shows PAOs activity was closely related to PHA accumulation. However, the PHA accumulation under the anaerobic phase would be dependent on the hydrolysis of the complex carbon source into short chain fatty acids (SCFA). The result would be demonstrated by the simple carbon source effect. The effect of the An/Ox time ratio on TP removal was significant. Shorter anaerobic time would result in insufficient phosphorus release and greater time would result in inactive PAOs. The appropriate An/Ox time ratio was suggested as 1/2. Comparisons of the phosphorus removal characteristics between biofilm and suspended growth under the same growth conditions are discussed in detail.
16S rRNA in situ probing for the determination of the family level community structure implicated in enhanced biological nutrient removal
Authors: Mudaly D. D. , Atkinson B. W. , Bux F.
Published: May 2018

Knowledge of a discrete physiological group capable of excess biological phosphate removal (EBPR) remains unclear. Consequently, microbial community analysis of an enhanced continuous laboratory-scale activated sludge process displaying a strong EBPR mechanism was conducted. Unit design was configured upon the three-stage Phoredox process and characterization of the activated sludge bacterial community was carried out using fluorescent in situ hybridization (FISH) techniques. Fixed activated sludge samples were hybridized with fluorescently labeled oligonucleotide probes targeting the following bacterial phylogenetic divisions: a kingdom level probe specific for all bacteria (EUB338); family level probes specific for the alpha, beta and gamma subclasses of the class Proteobacteria; Gram positive bacteria with a high (G+C) DNA content (GPBHGC) or Actinobacteria; the Cytophaga-Flavobacterium (CF) subclass within the Cytophaga-Flavobacterium-Bacteriodes division; and genus level probes specific for Pseudomonas spp., Aeromonas spp., and Acinetobacter spp. Bacterial predominance between the anaerobic, anoxic and aerobic zones of the EBPR sludge were comparable and appeared as follows; beta (22%), alpha (19%), gamma (17%), GPBHGC (11%) and CF (8%). The incidence of Acinetobacter spp. appeared to be generally low with counts amounting to <9% of the total bacterial count. A population shift in the alpha Proteobacteria subclass was evident between the non-nutrient removal seed sludge and the EBPR sludge, implicating this group in EBPR. The overall results indicate that the beta and alpha Proteobacteria can be metabolically functional in EBPR processes and reiterate the functional misconception of Acinetobacter spp. in EBPR systems.
Overview: full scale experience of the SHARON® process for treatment of rejection water of digested sludge dewatering
Authors: van Kempen R. , Mulder J. W. , Uijterlinde C. A. , Loosdrecht M. C.M.
Published: May 2018

A SHARON® system has been constructed at the Utrecht WWTP and at the Rotterdam Dokhaven WWTP. In the SHARON® process rejection water from dewatering of digested sludge is treated for N-removal. It concerns a high active process operating without sludge retention. Due to differences in growth rate nitrite oxidisers can be washed out of the system while ammonia oxidisers are maintained, resulting in N-removal over nitrite. The SHARON® process was selected in competition with several other techniques.

The feed of a SHARON® system is concentrated, with ammonia concentrations ranging from 0.5 to 1.5 g N/l. The results show that conversion rates of 90% are well possible with N-removal mainly via the nitrite route. The process was shown to be stable. Due to the high ammonium influent concentrations pH control is of great importance, preventing process inhibitions. The acidifying effect of nitrification can be compensated completely by CO2 stripping during aeration and by denitrification. Heat production by biological conversions is significant, due to the high inlet concentrations, and contributes to the optimal operating temperature of 30-40°C.
External nitrification in biological nutrient removal activated sludge systems
Authors: Hu Z.-R. , Wentzel M. C. , Ekama G. A.
Published: May 2018

A biological nutrient removal (BNR) activated sludge (AS) scheme incorporating external nitrification in a fixed media system is evaluated. A laboratory scale investigation of the scheme indicates that it holds considerable potential for BNRAS system intensification through major reduction in sludge age and oxygen demand and significant improvement in sludge settleability. Because the BNRAS system is not required to nitrify, its anoxic mass fraction can be considerably enlarged at the expense of the aerobic mass fraction creating conditions that (i) allow it to achieve high N removals with domestic wastewaters with high TKN/COD ratios and (ii) promote anoxic P uptake polyphosphate accumulating organisms (PAO) to develop in the system. From this, and earlier investigations with conventional BNR systems, it appears that anoxic P uptake biological excess P removal (BEPR) is only about two thirds of aerobic P uptake BEPR. Inclusion of anoxic P uptake PAOs in, and exclusion of nitrifiers from, the BNRAS system are not essential for the scheme. However, conditions that promote aerobic P uptake to maximize BEPR, are also conducive to nitrifier growth, which, if supported in the BNRAS system, would require virtual complete nitrification in the fixed media system to avoid nitrate interference with BEPR. Before the scheme can be implemented at large scale, an engineering and economic evaluation is required to quantify its potential benefits and savings.
Possible impact of treated wastewater discharge on incidence of antibiotic resistant bacteria in river water
Authors: Iwane T. , Urase T. , Yamamoto K.
Published: May 2018

Escherichia coli and coliform group bacteria resistant to seven antibiotics were investigated in the Tama River, a typical urbanized river in Tokyo, Japan, and at a wastewater treatment plant located on the river. The percentages of antibiotic resistance in the wastewater effluent were, in most cases, higher than the percentages in the river water, which were observed increasing downstream. Since the possible increase in the percentages in the river was associated with treated wastewater discharges, it was concluded that the river, which is contaminated by treated wastewater with many kinds of pollutants, is also contaminated with antibiotic resistant coliform group bacteria and E.coli. The percentages of resistant bacteria in the wastewater treatment plant were mostly observed decreasing during the treatment process. It was also demonstrated that the percentages of resistance in raw sewage are significantly higher than those in the river water and that the wastewater treatment process investigated in this study works against most of resistant bacteria in sewage.
Study on endocrine disrupting chemicals in wastewater treatment plants
Authors: Nasu M. , Goto M. , Kato H. , Oshima Y. , Tanaka H.
Published: May 2018

From July 1998 to March 1999, a study was made of a total of 27 treatment plants for the principal purpose of understanding the actual condition of endocrine disrupting chemicals (EDCs) in sewage, and the behavior of EDCs in wastewater treatment plants.

The results showed actual levels of influent and effluent concentrations of EDCs in sewage. Substances detected above the minimum limit of determination were 15 for wastewater influent and 6 for effluent. Similarly, nonyl phenol ethoxylate and 17β-estradiol, which are highlighted as pertinent substances, were detected. It was confirmed that the reduction ratio of EDCs in treatment plants was 90% or more for almost all substances.

The behavior of EDCs in general in treatment plants was also studied. As a result, the EDCs reduction effect was recognized in both the primary settling tank and biological reaction tank, though the trend varies among substances.
GREAT-ER: a new tool for management and risk assessment of chemicals in river basins Contribution to GREAT-ER No.10
Authors: Schowanek D. , Fox K. , Holt M. , Schroeder F. R. , Koch V. , Cassani G. , Matthies M. , Boeije G. , Vanrolleghem P. , Young A. , Morris G. , Gandolfi C. , Feijtel T. C.
Published: May 2018

The GREAT-ER (Geo-referenced Regional Exposure Assessment Tool for European Rivers) project team has developed and validated an accurate aquatic chemical exposure prediction tool for use within environmental risk assessment schemes. The software system GREAT-ER 1.0 calculates the distribution of predicted environmental concentrations (PECs) of consumer chemicals in surface waters, for individual river stretches as well as for entire catchments. The system uses an ARC/INFO – ArcView (® ESRI) based Geographical Information System (GIS) for data storage and visualization, combined with simple mathematical models for prediction of chemical fate. At present, the system contains information for four catchments in Yorkshire, one catchment in Italy, and two in Germany, while other river basins are being added. Great-ER 1.0 has been validated by comparing simulations with the results of an extensive monitoring campaign for two ‘down-the-drain’ chemicals, i.e. the detergent ingredients boron and Linear Alkylbenzene Sulphonate (LAS). GREAT-ER 1.0 is currently being expanded with models for the terrestrial (diffuse input), air and estaurine compartments.
Predicting soil-water partition coefficients for Hg(II) from soil properties
Authors: Lee S.-Z. , Chang L. , Chen C.-M. , Tsai Y. I. , Liu M.-C.
Published: May 2018

The metal adsorption characteristics for fifteen Taiwan soils by Hg(II), were evaluated using pH as the major variable. The soil samples were thoroughly characterized for their physical chemical properties and composition, particularly organic matter and metal oxides. The adsorption of Hg(II) increased with increasing pH between pH 2.5 and 5.5, whereas the adsorption significantly decreased above around pH 5.5. Below pH 5.5, greater adsorption was found for soils with a higher organic matter content at constant pH and metal concentration. To better understand the mechanism of adsorption, the experimental results for Hg (II) were tested in a partition coefficient model to relate the adsorption of the Hg(II) by the different soils with soil components: organic matter, iron oxide, aluminium oxide and manganese oxide. This model was not successful when applied to measurements at the differing natural soil pHs because of the importance of pH. At pH greater than 5.5 the model fails because of the complexation of Hg by the dissolved organic matter. However, partition coefficients obtained from experimental data were highly correlated with those calculated for a partition coefficient between mercury and organic matter alone at lower pH. Normalization of the partition coefficients, Kd, for the organic matter content of the soils, Kom, greatly improved the correlation between the partition coefficient and pH under pH 5.5 (R2 increased from 0.484 to 0.716). This suggests that the surficial adsorption sites are principally due to organic matter for pH less than 5.5. For the 24-hour equilibration period employed, diffusion of Hg through this superficial organic matter coating to underlying sorptive materials, including metal oxides, is not important in the partitioning of Hg. At pH above 5, a decrease of mercury adsorption with increasing solution pH was also found. This result may be explained in part by the complexation of mercury by soil dissolved organic matter whose concentration increased with increasing pH.
Removal of hydrophobic dyestuff from dyeing wastewater by photo-sensitization process
Authors: Tsui S. M. , Chu W. , Fung P. C. , Sin K. M.
Published: May 2018

Recently, photochemical reaction became more important in view of using UV in textile dyeing wastewater treatment processes, in which neither chemical sludges nor toxic residues are left in the treated effluent. The photodegradation of hydrophobic dye (Palanil Yellow 5R, PY-5R) in the presence of acetone, which performs as a solvent and/or a photo-sensitizer, was investigated in this study. The results demonstrated that photochemical reaction in the presence of acetone could rapidly and effectively enhance color removal at a wavelength of 253.7 nm. The photodegradation follows pseudo first-order decay. The rate constants and decay quantum yields of dye degradation by UV depend on the solution pH and solvent system, (i.e., acetone to water ratio). The photosensitization of the disperse dye was found to be optimized at pH 9 and in 0.5 (v:v) acetone-water ratio.
Denitrifying phosphorus removal by anaerobic/anoxic sequencing batch reactor
Authors: Ng W. J. , Ong S. L. , Hu J. Y.
Published: May 2018

Denitrifying phosphorus removal was verified in a laboratory anaerobic/anoxic Sequencing Batch Reactor (A/A SBR) for a period of 18 months. The results obtained demonstrated the ability of the anaerobic/anoxic strategy to enrich the growth of denitrifying phosphorus bacteria (DPB) capable of taking up phosphate under anoxic conditions by using nitrate as the electron acceptor. Phosphorus removal efficiency ranging from 40-100% could be attained in an A/A SBR system. Simultaneous anoxic phosphate uptake and biological denitrification under anaerobic/anoxic condition occurred in this system. Batch tests showed, however, that simultaneous presence of carbon and nitrate would be detrimental to denitrifying phosphorus removal. Results of bacteria studies suggested that three denitrifying isolates had aerobic phosphorus removing ability.
Phosphorus removal from SBR with controlled denitrification for weak sewage
Authors: Choi E. , Park H. , Rhu D.
Published: May 2018

Most SBRs operating for weak sewage have a tendency of poor removal of phosphorus due to NO3N inhibition. To minimize this inhibition, NO3N storage was utilized in this study. With influent BOD 100 mg/L and VFA 30 mg/L, a total of the maximum removable nitrogen and phosphorus was about 25 mg/L with 8 hr cycle. With this storage, VFA utilized for phosphorus removal could be maximized. The effluent nitrogen and phosphorus levels were generally 11 and 1 mg/L, respectively.
The anaerobic SBR process: basic principles for design and automation
Authors: Ruiz C. , Torrijos M. , Sousbie P. , Lebrato Martinez J. , Moletta R.
Published: May 2018

This study has determined the purification performance and the basic principles for the design of an anaerobic SBR (ASBR) to be used to treat wastewater generated in the food industries. Two ASBR's were set up and one fed with a slaughterhouse effluent at low concentration, the other with concentrated dairy wastewater. The maximum loading rate applied should not exceed 4.5 g of COD/L/day for the dilute effluent and 6 g of COD/L/day for the concentrated effluent. At higher loading rates, the reactors become difficult to operate, mainly because of sludge removal problems, and purification efficiency declines. A detailed study of the kinetics (TOC, VFA, rate of biogas production) throughout one treatment cycle led to the development of a simple control strategy based on the monitoring of the biogas production rate which was then applied to the reactor treating the dairy wastewater. After automation, the reactor worked free of problems at an average pollution load of 5.4 g of COD/L/day.
Simultaneous organic nitrogen and sulfate removal in an anaerobic GAC fluidised bed reactor
Authors: Fdz-Polanco F. , Fdz-Polanco M. , Fernandez N. , Urueña M. A. , García P. A. , Villaverde S.
Published: May 2018

A granular activated carbon (GAC) anaerobic fluidised bed reactor treating vinasse from an ethanol distillery of sugar beet molasses was operated for 250 days under three different organic loading rates. The reactor showed good performance in terms of organic matter removal and methane production but an anomalous behaviour in terms of unusual high concentrations of molecular nitrogen and low concentration of hydrogen sulphide in the biogas. The analysis of the different nitrogenous and sulphur compounds and the mass balances of these species in the liquid and gas phases clearly indicated an uncommon evolution of nitrogen and sulphur in the reactor. Up to 55% of the TKN and up to 80% of the sulphur disappear in the liquid phase This is the opposite to any previously reported results in the bibliography. The new postulated anaerobic process of ammonia and sulphate removal seems to follow the mechanism: SO4=+2NH4+ → S + N2 + 4H2O (ΔG° = - 47.8 kJ/mol).
From vision to action after the Second World Water Forum
Authors: Serageldin Ismail
Published: May 2018

The World Commission for Water in the 21st Century set out the vision of a ‘water secure world’ and suggested a comprehensive set of measures to achieve this aim. Criticism of the role of water pricing in these measures underestimates the strength of its case in environmental, financial, economic, social, political and ethical terms. The Framework For Action has been devised as a guide for local action, but the proposal for a Water Innovation Fund may have particular impact.
Bamboo as an anaerobic medium: effect of filter column height
Authors: Camargo S. A.R. , Nour E. A.A.
Published: May 2018

Sewage was treated in anaerobic filters filled with rings of bamboo (either whole or cut), and their effectiveness in the reduction of chemical oxygen demand (COD) was monitored along the entire extension of the filter. This efficiency was determined based on the COD reduction in both the brute effluent (COD-T) and that passed through a glass filter (COD-F). The quantity of total suspended solids (TSS) present at various heights in the filter column, measured at approximately 10-cm intervals from the false bottom to the height of the filter outflow (80 cm above) for various hydraulic detention times (HDT). The performance of the system resulted in little variation up to 5 hours of HDT, with the percentage of reduction of COD-T and COD-F being situated in the range of 60-80% and 40-80%, respectively. The first 40 cm of the filter proved to be relatively effective, and no significant differences in performance between whole and cut rings of bamboo were observed. A shock in pH occurring after 562 days of operation provoked an immediate and marked decrease in the performance of the reactors, especially that operating with a HDT of only 2 hours. This latter filter required more time to return to normal operational conditions than did the other reactors operating with longer HDT.
Salinization: unplumbed salt in a parched landscape
Authors: Williams W. D.
Published: May 2018

The global hydrological and salt cycles are described, as are the ways in which human activities have led to their disturbance. One effect of this disturbance is the unnatural increase in the salinity of many inland waters (secondary salinization). The geographical extent of secondary salinization is outlined, together with its effects on various types of inland waters, such as salt lakes, freshwater lakes and wetlands, and rivers and streams. The likely impact on salinization of global climate change is summarized.
Towards sustainable development: catalysts for change in industrial water management
Authors: Ayers Robert L.
Published: May 2018

“Business as usual is not an option.” Water management practices are changing too slowly and the global 'fresh water gap' continues to grow. Actions as must be taken by government and civic leaders. Industry also has a responsibility to act, but its inability to adequately meet the challenge to date points to the need for additional stimuli.

The current water crisis can be mitigated by changes in behaviour and perceptions. This presentation will argue that specific catalysts are required to encourage and support a dramatic shift of behaviours and perceptions by industry leaders. The catalysts include: establish clear and objective rules; introduce water pricing; recognize 'life cycle' costs; prioritize needs; reward small-scale solutions; nurture innovations; spread global best practices.

With the help of the catalysts described herein, industry can take its place as a leader in effective water management in the 21st Century. In partnership with governments, international organizations and civic organizations, industry leaders can help meet the challenge of the water crisis while creating sustainable economic growth.
Workshop 3 (synthesis): innovative processes in small scale agricultural production using water more effectively
Authors: Bras Rafael , Gordon Line
Published: May 2018

The workshop discussed the possibilities of innovative technologies to increase food production. Most of the concepts discussed are based on rainfall management, conservation and recycling. Simple technologies, adopted to local circumstances, can increase farm yields in small-scale agriculture. Small-scale rainfed agriculture is viable with intelligent utilisation of harvested rainfall. These small-scale technologies need however to be complemented with educational programs, incentives and trade to be broadly adopted and effective. The need for better documentation of results was also raised in the discussion.
Workshop 4 (synthesis): responsibilities linked to 'human rights approach' to water - rules and roles
Authors: Barlow Maud , Söderbaum Peter
Published: May 2018

Thinking in terms of ethics and Human Rights raises issues of power and justice. It can be argued that there are indisputable human rights, e.g. when the construction of dams is considered, while 'commodification' of water and the 'market mentality' may suggest that everything can be traded.
Water law and human rights - roles and responsibilities
Authors: De Lange Marna
Published: May 2018

This paper focuses on the experience of South Africa in introducing water legislation based on human rights principles (in particular the National Water Act of 1998) and reflects on some practical implications for the implementation of water management in a country with limited water and financial resources.
Anaerobic oxidation of cholesterol by a denitrifying enrichment
Authors: Barrandeguy E. , Tarlera S.
Published: May 2018

Sterols (e.g. cholesterol) present in wool scouring effluent represent the most recalcitrant fraction in anaerobic treatment. This study was conducted to examine the feasibility of removal of this organic load through a denitrifying post-treatment stage. A stable cholesterol-denitrifying enrichment (CHOL-1) was obtained from sludge of a bench-scale upflow sludge bed (USB) denitrifying reactor integrated to a carbon and nitrogen removal system for sanitary landfill leachate. According to the amounts of cholesterol degraded and of nitrite and nitrogen gas formed, the capacity for complete cholesterol oxidation under anaerobic conditions by CHOL-1 can be assumed. Nitrite accumulation observed at a low C/N ratio outlines the importance of determining the optimal C/N ratio for adequate denitrifying reactor performance. The enrichment was partly identified with molecular analysis of cloned 16S rDNA sequences revealing the presence of two groups of bacteria belonging to the β subclass of the Proteobacteria. According to analysis of sequences, it can be inferred that a yet uncultivated new bacterium is the one responsible for cholesterol oxidation. Results of this study suggest that sludge from a denitrifying reactor treating leachate is potentially useful in a combined anaerobic-anoxic system for degradation of cholesterol that remains after methanogenic treatment.
Stimulating grassroot creativity for quality of life and quality of environment
Authors: Raka Gede
Published: May 2018

This paper discusses an experiment on creativity development, a systematic endeavour aimed at empowering teachers and school principals through enhancement of their capacities to introduce and manage change at their schools. It focuses on enabling them to create learning processes and climates that stimulate creativity, especially creativity that enables students to self-help and to care for the environment. The experiment uses universities as 'beach-heads'. A group of university lecturers interested to join the program is functioning as trainer, consultant, motivator, network builder, partner, and facilitator for the teachers. The undertaking applies a multifaceted approach, involving the creation of a sense of urgency to change, restoring self-respect of the teachers. It also includes ways of starting the change from oneself, encouraging small but many practical meaningful activities, process oriented, recognizing efforts, collaborative network, cascading expansion, snowballing effects, self-selection and creating common ownership. This experiment had developed many self-organizing learning communities, inter-related and mutually benefiting in a national network for creativity. The teachers' involvement in creativity activities had brought changes in their attitudes toward students, their profession, environment, and toward change itself.
Report from the Poster Session
Authors: Brattberg Gunilla
Published: May 2018

Among many good posters it was a difficult task to choose the best one and the panel - elected from among the members of the Scientific Program Committee of the Stockholm Water Symposium - has done a thorough job.
River Water Quality Model no. 1 (RWQM1): I. Modelling approach
Authors: Shanahan P. , Borchardt D. , Henze M. , Rauch W. , Reichert P. , Somlyódy L. , Vanrolleghem P.
Published: May 2018

Successful river water quality modelling requires the specification of an appropriate model structure and process formulation. Both must be related to the compartment structure of running water ecosystems including their longitudinal, vertical, and lateral zonation patterns. Furthermore, the temporal variability of abiotic boundary conditions may be important and must be incorporated by an appropriate choice of model parameters. A six-step decision procedure is proposed to achieve these objectives. The steps address the determination of the following model features: (1) temporal representation (dynamic or steady-state); (2) model dimensionality; (3) mixing; (4) advection; (5) reaction terms; and (6) boundary conditions. Numerical criteria based on process time constants and length scales provide a basis for these decisions.
Urban drainage redefined: from stormwater removal to integrated management
Authors: Chocat B. , Krebs P. , Marsalek J. , Rauch W. , Schilling W.
Published: May 2018

Even though urban drainage has been practised for more than 5000 years, many challenges arising from growing demands on drainage still remain with respect to runoff quantity and quality; landscape aesthetics, ecology and beneficial uses; and operation of existing urban wastewater systems. Further advances can be achieved by adopting an integrated approach, optimal operation of the existing infrastructure, advanced pollution and runoff source controls, improved resilience of receiving waters, and adaptive water management. The specific research needs include new technologies and strategies for stormwater management, advanced treatment of urban wet-weather effluents, and tools for analysis and operation of drainage systems. High diversity of demands on, and region/site specific conditions of, urban drainage shapes the role of urban drainage experts – as mediators among the many stakeholders and fields involved.
Photochemical-biological treatment of a real industrial biorecalcitrant wastewater containing 5-amino-6-methyl-2-benzimidazolone
Authors: Sarria V. , Parra S. , Invernizzi M. , Péringer P. , Pulgarin C.
Published: May 2018

5-amino-6-methyl-2-benzimidazolone (AMBI), used in the manufacture of dyes, was characterised as a biorecalcitrant compound by means of different biodegradability tests. In order to enhance the biodegradability of this important pollutant, the application of Advanced Oxidation Process (AOPs) as a pre-treatment was explored. Some experiments were addressed to find the most efficient AOP. The systems H2O2/hv, TiO2/H2O2/hv, Fe3+/hv, Fe3+/H2O2 and Fe3+/H2O2/hv were compared. The photo-Fenton system was the most efficient and the optimal conditions (AMBI, Fe3+, H2O2 concentrations) for the degradation of AMBI were found. During the photo-Fenton degradation, experiments were also made to obtain information concerning the evolution of: (a) organic carbon and initial compound concentration; (b) the oxidation state; (c) the toxicity; (d) the biodegradability; and (e) the chemical nature of the intermediates. These analyses show that the solution resulting from the treatment of AMBI is biologically compatible and complete mineralisation can be performed by biological means. A combined photochemical (Fenton) and biological flow reactor for the degradation of AMBI was successfully operated in continuous mode at laboratory scale. 100% of the initial concentration of AMBI and 80.3% of Dissolved Organic Carbon (DOC) were removed in 3.5 hours of total residence time. Finally, some field experiments under direct sunlight carried out at the Plataforma Solar de Almeria, Spain, demonstrated that this solar catalytic system is an effective treatment for this kind of industrial wastewater.
Comparison of suspended and fixed photocatalytic reactor systems
Authors: Geissen S.-U. , Xi W. , Weidemeyer A. , Vogelpohl A. , Bousselmi L. , Ghrabi A. , Ennabli A.
Published: May 2018

Photocatalysis is a promising technology for the purification of pretreated wastewaters in sun-rich countries if an economically applicable reactor system is available. Within this project the catalyst separation as an essential process step of suspended reactor systems was investigated. For the separation of suspended catalyst a sedimentation basin with and without lamella and a membrane filtration were investigated. The sedimentation was found to be very sensitive to the kind of the ion background of wastewater, the pH, the TiO2 influent concentration as well as the hydrodynamics in the clarifier. Under optimized conditions effluent concentrations of less than 5 mg SS/L and a clear water without turbidity could be reached with a specific flow rate of up to 0.7 m3/m2/h. The best performance for P25 was achieved with a TiO2 influent concentration of 5 g/L. Membrane filtration was the only method to guarantee a complete retention of the TiO2 as well as a rejection of microorganisms and high molecular compounds. With cross-flow velocities of 3 m/s and a transmembrane pressure of 100 kPa flux rates up to 1200 L/m2/h were achieved. A flow-film-reactor (FFR) was operated with the model compound DCA under identical conditions with fixed and suspended TiO2. Whereas the fixed system has the advantage that no separation step is necessary and a simple construction can be used, suspended systems offer a three times higher reaction velocity for a catalyst concentration of 10 g/L, but are also characterized by higher investment costs.
Soil characteristics and agrichemicals in groundwater of the Midwestern United States
Authors: Burkart M. , Kolpin D. W. , Jaquis R. , Cole K.
Published: May 2018

A comprehensive set of soil characteristics were examined to determine the effect of soil on the transport of agrichemicals to groundwater. This paper examines the relation of soil characteristics to concentrations and occurrence nitrate, atrazine, and atrazine residue from 99 wells completed in unconsolidated aquifers across the Midwestern United States. Soil characteristics that determine the rate of water movement were directly related to the occurrence and concentrations of nitrate and atrazine in groundwater. The substantial differences in the relations found among soil characteristics and nitrate and atrazine in groundwater suggest that different processes affect the transformation, adsorption, and transport of these contaminants. A multi-variable analysis determined that the soil characteristics examined explained the amount of variability in concentrations for nitrate (19%), atrazine (33%), and atrazine residue (29%). These results document that, although soils do affect the transport of agrichemicals to groundwater, other factors such as hydrology, land use, and climate must also be considered to understand the occurrence of agrichemicals in groundwater.
Water treatment by TiO2 photocatalysis and/or ultrasound: degradations of phenyltrifluoromethylketone, a trifluoroacetic-acid-forming pollutant, and octan-1-ol, a very hydrophobic pollutant
Authors: Théron P. , Pichat P. , Petrier C. , Guillard C.
Published: May 2018

TiO2 photocatalysis and ultrasound are advanced oxidation processes for water treatment. Our study aimed at showing, via the purposely chosen title compounds, that these techniques can be complementary. For C6H5COCF3 (PTMK), the photocatalytic removal rate was higher than the ultrasonic (515 kHz) removal rate in the presence of TiO2 in the dark, whereas it was the opposite for octan-1-ol under the conditions employed. Simultaneous UV and ultrasound irradiation of the TiO2 suspension led, for PTMK, to a removal rate about equal to the sum of the removal rates observed for separate irradiations, and decreased by a factor of approximately 20% for octan-1-ol as if the photocatalytic degradation was suppressed by the dominant distribution of octan-1-ol to the cavitation bubbles. This distribution was substantiated by the large detrimental effect of octan-1-ol on the PTMK ultrasonic removal rate. The concurrent use of both techniques allowed a faster removal of both pollutants in binary mixtures. The amount of CF3COOH from PTMK was approximately eight times lower in sonicated, than in UV-irradiated, TiO2 suspensions. Several intermediate products showed the occurrence of chemical transformations occurring in and/or on the cavitation bubbles. COD decline and CO2 formation were initially higher for ultrasonic than for photocatalytic treatment. However, complete mineralization (except for CF3COOH) was achieved more rapidly by photocatalysis and even more rapidly by simultaneous use of both techniques.
Deriving robust operating rules for the interim control of the Kirazdere reservoir
Authors: Rao Z. , O'Connell P. E. , Cook D. J. , Jamieson D. G.
Published: May 2018

A methodology is developed for deriving robust operating rules for the interim control of a multipurpose reservoir. The methodology includes the generation of policies using optimisation models, the derivation of robust operating rules using artificial neural networks and the evaluation of the identified policies through simulation. The approach developed is demonstrated through an application to the Kirazdere Reservoir located on the Kiraz River in Turkey.
Determination of photonic efficiency and quantum yield of formaldehyde formation in the presence of various TiO2 photocatalysts
Authors: Wang C. , Bahnemann D.W. , Dohrmann J.K.
Published: May 2018

Illumination of aqueous TiO2 suspentions yields hydroxyl radicals, which can be trapped by methanol producing formaldehyde (HCHO). In this work, the photonic efficiency and quantum yield of HCHO formation in colloidal TiO2 solutions and, P25 and UV 100 suspensions have been determined. Differences in photocatalytic activity of the three photocatalysts have been found and are discussed. The photonic efficiency of HCHO formation in the presence of P25 and UV 100 depends on the concentration of TiO2 and the pH. The critical concentration is 2.5 g/L. Below this, the photonic efficiency with P 25 is higher than with UV 100, and vice versa. Optimum pH values for P25 and UV 100 giving the maximum photonic efficiency are 7.7 and 10.4, respectively. Compared to P25 and UV 100, the true quantum yield of HCHO formation in colloidal TiO2 solution varies a little with pH and virtually does not change with the amount of loading of TiO2. The true quantum yield varies as the inverse square root of light intensity. The quantum yield increases from 0.02 to 0.08 when the absorbed photon flux decreases from 8.1 × 10-7 Ein/L s to 4.9 × 10-8 Ein/L s. A simple model is presented to explain the experimental observation.
Waste design and source control lead to flexibility in wastewater management
Authors: Larsen T. A. , Gujer W.
Published: May 2018

The concepts of waste design and source control are introduced as contracts between wastewater handling agencies and consumers and consumers and industry respectively. Waste design serves to produce waste streams that are optimized in composition and time sequence for easy transport and treatment. Source control makes services and installations available, which allow the consumer to adhere to the specifications of waste design. Increased delegation of responsibility to the consumer is expected to result in more flexible wastewater handling systems.
Relevance of microbial extracellular polymeric substances (EPSs) - Part I: Structural and ecological aspects
Authors: Flemming H.-C. , Wingender J.
Published: May 2018

Extracellular polymeric substances are the construction materials for microbial aggregates such as biofilms, flocs (“planktonic biofilms”) and sludge. Their major components are not only polysaccharides but also proteins and in some cases lipids, with minor contents of nucleic acids and other biopolymers. In the EPS, biofilm organisms can establish stable arrangements and function multicellularly as synergistic microconsortia. The matrix facilitates the retention of exoenzymes, cellular debris and genetic material; it can be considered as a microbial recycling yard. Gradients can develop due to the physiological activity and the fact that diffusive mass transport prevails over convective transport in the matrix. Biofilm cells tolerate higher concentrations of many biocides. The EPS matrix sequesters nutrients from the water phase. In photosynthetic communities, EPS molecules can function as light transmitters and provide photons to organisms located deeper in a microbial mat. The EPS matrix is a dynamic system, constructed by the organisms and responding to environmental changes. It enables the cells to function in a manner similar to multicellular organisms.
Eutrophication study of twenty reservoirs in Taiwan
Authors: Chang S. -P. , Chuang S. -M.
Published: May 2018

Taiwan is an island off the southeastern coast of China with total area of roughly 36,000 km2. The geographic position of Taiwan is between 21° 45′ 25″ to 25° 56′ 31″ north latitude and 119° 18′ 3″ to 124° 34′ 30″ east longitude and includes both tropical and subtropical areas. The study was carried out at twenty main reservoirs in Taiwan area from 1994 to 1998. The study revealed that the water quality of most reservoirs gradually deteriorated during the study period. Total phosphorus concentrations over 60 μg/L were observed in 12.5% of these reservoirs in 1994, but in 22.2% of these reservoirs in 1998. Total nitrogen concentrations over 1.0 mg/L were observed in 37.5% of these reservoirs in 1994, but in 94.4% of these reservoirs in 1998. Secchi disc transparency below 2 m was observed in 75% of these reservoirs in 1994, but in 83.3% of these reservoirs in 1998. Chlorophyll a concentrations over 15 mg/m3 were observed in 12.5% of these reservoirs in 1994, but in 27.8% of these reservoirs in 1998. The TN:TP mass ratios (wt/wt) of all the studied reservoirs except Akungting Reservoir, Fongshan Reservoir, and Chengching Reservoir are higher than 16. The study results on nutrient limitation indicated that phosphorus is the primary limiting nutrient in Taiwan reservoirs except Akungting Reservoir, Fongshan Reservoir, and Chengching Reservoir.