ALBERT

Description: Nanofiltration for water and wastewater treatment – a mini review Drinking Water Engineering and Science, 6, 47-53, 2013 Author(s): H. K. Shon, S. Phuntsho, D. S. Chaudhary, S. Vigneswaran, and J. Cho The application of membrane technology in water and wastewater treatment is increasing due to stringent water quality standards. Nanofiltration (NF) is one of the widely used membrane processes for water and wastewater treatment in addition to other applications such as desalination. NF has replaced reverse osmosis (RO) membranes in many applications due to lower energy consumption and higher flux rates. This paper briefly reviews the application of NF for water and wastewater treatment including fundamentals, mechanisms, fouling challenges and their controls.

Description: Application of DVC-FISH method in tracking Escherichia coli in drinking water distribution networks Drinking Water Engineering and Science, 6, 25-31, 2013 Author(s): L. Mezule, S. Larsson, and T. Juhna Sporadic detection of live (viable) Escherichia coli in drinking water and biofilm with molecular methods but not with standard plate counts has raised concerns about the reliability of this indicator in the surveillance of drinking water safety. The aim of this study was to determine spatial distribution of different viability forms of E. coli in a drinking water distribution system which complies with European Drinking Water Directive (98/83/EC). For two years coupons (two week old) and pre-concentrated (100 times with ultrafilters) water samples were collected after treatment plants and from four sites in the distribution network at several distances. The samples were analyzed for total, viable (able to divide as DVC-FISH positive) and cultivable E. coli . The results showed that low numbers of E. coli enters the distribution sytem from the treatment plants and tend to accumulate in the biofilm of water distribution system. Almost all of the samples contained metabolically active E. coli in the range of 1 to 50 cells per litre or cm 2 which represented approximately 53% of all E. coli detected. The amount of viable E. coli significantly increased into the network irrespective of the season. The study has shown that DVC-FISH method in combination with water pre-concentration and biofilm sampling allows to better understand the behaviour of E. coli in water distribution networks, thus, it provides new evidences for water safety control.

Description: Fluoride in the drinking water of Pakistan and the possible risk of crippling fluorosis Drinking Water Engineering and Science, 6, 17-23, 2013 Author(s): M. A. Tahir and H. Rasheed To explore the possibility of fluoride toxicity, 747 water samples were collected from surface water and groundwater sources of 16 major cities of Pakistan, adopting a uniform sampling design with distribution of samples: Lahore (79), Kasur (46), Faisalabad (30), Khushab (50), Chakwal (51), Mianwali (30), Jhelum (53), Bahawalpur (60), Karachi (60), Mirpur Khas (55), Peshawar (38), Risalpur (35), Quetta (81), Ziarat (21), Loralai (21), and Mastung (37). Comparison of analytical findings with WHO Guidelines of Drinking Water for Fluoride (i.e., 1.5 ppm) has concluded that 16% of the monitored water sources have fluoride concentration beyond the permissible safe limit of 1.5 mg L −1 falling in the concentration range of 1.6–25 mg L −1 . The highest fluoride contamination (22%) is detected in the Balochistan province followed by 19% in Punjab province. Comparatively higher fluoride levels of 〉 20% in the groundwater sources like hand pumps supported the possibility of increased groundwater contamination as excessive fluoride concentrations are expected to come from calcium-poor aquifers and in areas where fluoride-bearing minerals are common or where cation exchange of sodium for calcium occurs. Field observations have also indicated the prevalence of fluoride-associated health implications in the study areas with excessive fluoride in water sources. Findings of this study have provided bidirectional vision for the epidemiological investigations as well as to mitigate the issues in the affected vicinities of fluoride-rich areas.

Description: Technical Note: Wet validation of optical tomography for drinking water discolouration studies Drinking Water Engineering and Science Discussions, 6, 27-38, 2013 Author(s): R. Floris, P. van Thienen, and H. Beverloo This paper presents a set of validation experiments for the reconstruction of a cross-sectional particle concentration field in a transparent pipe filled with a fluid using optical tomography.

Description: Numerical and experimental investigation of leaks in viscoelastic pressurized pipe flow Drinking Water Engineering and Science, 6, 11-16, 2013 Author(s): S. Meniconi, B. Brunone, M. Ferrante, and C. Massari This paper extends the analysis concerning the importance in numerical models of unsteady friction and viscoelasticity to transients in plastic pipes with an external flow due to a leak. In fact recently such a benchmarking analysis has been executed for the cases of a constant diameter pipe (Duan et al., 2010), a pipe with a partially closed in-line valve (Meniconi et al., 2012a), and a pipe with cross-section changes in series (Meniconi et al., 2012b). Tests are based on laboratory experiments carried out at the Water Engineering Laboratory (WEL) of the University of Perugia, Italy, and the use of different numerical models. The results show that it is crucial to take into account the viscoelasticity to simulate the main characteristics of the examined transients.

Description: Assessment of calculation methods for calcium carbonate saturation in drinking water for DIN 38404-10 compliance Drinking Water Engineering and Science Discussions, 6, 167-198, 2013 Author(s): P. J. de Moel, A. W. C. van der Helm, M. van Rijn, J. C. van Dijk, and W. G. J. van der Meer The new German standard for calcium carbonate saturation in drinking water, DIN 38404-10, 2012 (DIN), marks a change in drinking water standardization from using simplified equations applicable for nomographs and simple calculators to using extensive chemical modeling requiring computer programs. The standard specifies the chemical outlines for the modeling and presents a dataset with 10 water samples for validating used computer programs. The DIN standard, as well as the Standard Methods 2330 (SM) and NEN 6533 (NEN) for calculation of calcium carbonate saturation in drinking water were translated into chemical databases for use in PHREEQC (USGS, 2013). This novel approach gave the possibility to compare the calculations as defined in the standards and internationally accepted chemical databases provided with PHREEQC. From the research it is concluded that the computer program PHREEQC with the developed chemical database din38404-10_2012.dat complies with the DIN standard for calculating Saturation Index (SI) and Calcite Dissolution Capacity (Calcitlösekapazität) or Calcium Carbonate Precipitation Potential (CCPP). This compliance is achieved by assuming equal values for molarity as used in DIN (obsolete) and molality as used in PHREEQC. From comparison with internationally accepted chemical databases it is concluded that the use of molarity limits the use of DIN to a maximum temperature of 45 °C. For current practical applications in water treatment and drinking water applications, the PHREEQC database stimela.dat was developed within the Stimela platform of Delft University of Technology. This database is an extension of the internationally accepted chemical database phreeqc.dat and thus in compliance with Standard Methods 2330. The database stimela.dat is also applicable for hot and boiling water, which is important in drinking water supply with regard to scaling of calcium carbonate in in-house drinking water practices. The SM and NEN proved to be not accurate enough to comply with DIN, because of their simplifications. The differences in calculation results for DIN, SM and NEN illustrate the need for international unification of the standard for calcium carbonate saturation in drinking water.

Description: 〈b〉Effectiveness of acidizing geothermal wells in the South German Molasse Basin〈/b〉〈br〉 S. Schumacher and R. Schulz〈br〉 Geoth. Energ. Sci., 1, 1-11, https://doi.org/10.5194/gtes-1-1-2013, 2013〈br〉 In Germany, many hydro-geothermal plants have been constructed in recent years, primarily in the region of Munich. As the host formation here mainly consists of carbonates, nearly all recently drilled wells have been acidized in order to improve the well yield. In this study, the effectiveness of these acid treatments is analyzed with respect to the amount of acid used and the number of acid treatments carried out per well. The results show that the first acid treatment has the largest effect, while subsequent acidizing improves the well only marginally. Data also indicate that continued acidizing can lead to degradation of the well. These findings may not only be important for geothermal installations in Germany but also for projects, for example, in Austria, France or China where geothermal energy is produced from carbonate formations as well.

Description: Nanofiltration for water and wastewater treatment – a mini review Drinking Water Engineering and Science Discussions, 6, 59-77, 2013 Author(s): H. K. Shon, S. Phuntsho, D. S. Chaudhary, S. Vigneswaran, and J. Cho The application of membrane technology in water and wastewater treatment is increasing due to stringent water quality standards. Nanofiltration (NF) is one of the widely used membrane processes for water and wastewater treatment in addition to other applications such as desalination. NF has replaced reverse osmosis (RO) membranes in many applications due to lower energy consumption and higher flux rates. This paper briefly reviews the application of NF for water and wastewater treatment including fundamentals of membrane process in general, mechanisms of NF process including few basic models. fouling challenges and their control mechanisms adopted.

Description: How much are households willing to contribute to the cost recovery of drinking water supply? Results from a household survey Drinking Water Engineering and Science, 6, 33-38, 2013 Author(s): S. Tarfasa Financial resources are crucial to improve existing urban drinking water supply in developing countries typically characterized by low cost recovery rates and high and rapidly growing demand for more reliable services. This study examines the willingness to pay for improved urban drinking water supply employing a choice model (CM) in an urban context in Ethiopia, Hawassa, with a household survey of 170 respondents. The design of the choice model allows the estimation of the values of two attributes of urban drinking water service (extra day water delivery per week and safer water). The findings indicate that households are willing to pay up to 60% extra for improved levels of water supply over and above their current water bill. Especially those households living in the poorest part of the city with the lowest service levels demonstrate that they are willing to pay more despite significant income constraints they are facing. Women value the improvement of water quality most, while a significant effect is found for averting behavior and expenditures. The estimated economic values can be used in policy appraisals of investment decisions.

Description: Removal and transformation of pharmaceuticals in wastewater treatment plants and constructed wetlands Drinking Water Engineering and Science Discussions, 6, 97-117, 2013 Author(s): E. Lee, S. Lee, J. Park, Y. Kim, and J. Cho Since trace organic compounds such as pharmaceuticals in surface water have been a relevant threat to drinking water supplies, in this study the removal of pharmaceuticals and transformation of pharmaceuticals into metabolites were investigated in the main sources of micropollutants such as wastewater treatment plants (WWTPs) and engineered constructed wetlands. Pharmaceuticals were effectively removed by different WWTP processes and wetlands. Pharmaceutical metabolites with relatively low log D value resulted in the low removal efficiencies compared to parent compounds with relatively high log D value, indicating the stability of metabolites. And the constructed wetlands fed with wastewater effluent were encouraged to prevent direct release of micropollutants into surface waters. Among various pharmaceuticals, different transformation pattern of ibuprofen was observed with significant formation of 1-hydroxy-ibuprofen during biological treatment in WWTP, indicating preferential biotransformation of ibuprofen. Lastly, transformation of pharmaceuticals depending on their structural position was investigated in terms of electron density, and the electron rich C 1 = C 2 bond of carbamazepine was revealed as an initial transformation position.

Description: Effects of network pressure on water meter under-registration: an experimental analysis Drinking Water Engineering and Science Discussions, 6, 119-149, 2013 Author(s): C. M. Fontanazza, V. Notaro, V. Puleo, and G. Freni In water supply systems, a considerable amount of apparent loss is caused by meter under-registration. Water meters are subject to intrinsic systemic error depending on the actual flow rates passing through them. Furthermore, the moving parts of the meter are subject to wear and tear that progressively reduce meter accuracy. The increase in systemic error is especially evident at low flow rates because of growing friction in the rotating mechanism, which requires a higher flow to start the meter (starting flow). The aim of this paper is to experimentally investigate metering error in an attempt to find a direct link between meter age, network pressure and apparent losses caused by the inability of the meter to accurately register the volume passing though it at low flow rates. The study was performed through laboratory experiments in which worn-out water meters were tested using a test bench. The results of the laboratory experiments show that ageing and pressure are both relevant parameters for determining meter starting flow. These results were then applied to assess the effects on apparent losses of the age of the meter, varying pressure values upstream of the meter (the pressure in the network where the meter is installed) and different patterns of flow rates passing through the device (the consumption pattern of the user). The presented results are useful for understanding the effects of operating conditions on water meter under-registration, which can aid water managers in implementing effective replacement campaigns.

Description: Present challenges for future water sustainable cities: a case study from Italy Drinking Water Engineering and Science Discussions, 6, 151-166, 2013 Author(s): L. Bonzanigo and G. Sinnona The global population is increasingly concentrated in cities. Cities and urban areas face many challenges – economic, social, health and environmental – which are often exacerbated by an increase in the frequency of natural disasters. Together, these challenges call for a shift towards sustainable cities which reduce their impact on the surrounding environment, whilst at the same time succeeding to make resources available to their increasing number of inhabitants. This article explores the state of the art of water management practices of the highly urbanised Northern Italian region and plans and scope for the future development of water management. Although the region is at present not under severe water stress, recently some cities faced water scarcity problems and were forced to implement water rationing. We assessed the vulnerability of Parma and Ferrara to a water crisis, together with the regular and emergency adaptation measures already in place, and the forecast for the near future. In two workshops, the authors adapted the Australian concept of Water Sensitive Urban Design for the Italian context. Although the population remains generally unaware of the impact of the two latest severe drought events (2003 and 2006/7), many adaptation measures towards a more sustainable use of the water resource are already in place – technically, institutionally, and individually. Water managers consider however that the drastic and definite changes needed to integrate the urban water management cycle, and which minimise the ecological footprint of urban spaces, lay far in the future.

Description: Status of organochlorine pesticides in Ganga river basin: anthropogenic or glacial? Drinking Water Engineering and Science, 6, 69-80, 2013 Author(s): P. K. Mutiyar and A. K. Mittal This study reports the occurrences of organochlorine pesticides (OCPs) in the Ganga river basin covering 3 states, i.e., Uttarakhand, Uttar Pradesh and Bihar comprising 72% of total river stretch consisting of 82 sampling points covered through 3 sampling campaigns. Samples were monitored for 16 major OCPs, including hexachlorocyclohexanes (HCHs), Endosulfan group, Aldrin group, DDTs and Heptachlor group pesticides. The results showed the ng L −1 levels contamination of OCPs in all the stretches sampled during these campaigns. The results also revealed that different types of OCPs were dominating in different stretches in accordance with the land use practices and agricultural runoff generated from those stretches. HCHs were most frequently detected (detection rate = 75%) in mountainous stretch; Endosulfans were prominent in UP (detection rate = 75%) stretch while in BR stretch Aldrin group pesticides were paramount (detection rate = 34%). Source apportionment of the OCP's revealed that in the upper reaches of the Ganges i.e., in the state of Uttarakhand, the glacial melt may be responsible for the presence of OCP's. In the lower reaches, intensive agriculture and industrial activities may be significantly contributing these pesticides. The samples from tributaries of Ganga river were found to contain higher numbers of pesticides as well as higher concentrations. The maximum total pesticide concentration in an individual sample during these sampling campaigns was found in the Son river sample (0.17 μg L −1 , Location: Koilwar, Bhojpur, Bihar).

Description: The large-scale impact of climate change to Mississippi flood hazard in New Orleans Drinking Water Engineering and Science, 6, 81-87, 2013 Author(s): T. L. A. Driessen and M. van Ledden The objective of this paper was to describe the impact of climate change on the Mississippi River flood hazard in the New Orleans area. This city has a unique flood risk management challenge, heavily influenced by climate change, since it faces flood hazards from multiple geographical locations (e.g. Lake Pontchartrain and Mississippi River) and multiple sources (hurricane, river, rainfall). Also the low elevation and significant subsidence rate of the Greater New Orleans area poses a high risk and challenges the water management of this urban area. Its vulnerability to flooding became dramatically apparent during Hurricane Katrina in 2005 with huge economic losses and a large number of casualties. A SOBEK Rural 1DFLOW model was set up to simulate the general hydrodynamics. This model included the two important spillways that are operated during high flow conditions. A weighted multi-criteria calibration procedure was performed to calibrate the model for high flows. Validation for floods in 2011 indicated a reasonable performance for high flows and clearly demonstrated the influence of the spillways. 32 different scenarios were defined which included the relatively large sea level rise and the changing discharge regime that is expected due to climate change. The impact of these scenarios on the water levels near New Orleans were analysed by the hydrodynamic model. Results showed that during high flows New Orleans will not be affected by varying discharge regimes, since the presence of the spillways ensures a constant discharge through the city. In contrary, sea level rise is expected to push water levels upwards. The effect of sea level rise will be noticeable even more than 470 km upstream. Climate change impacts necessitate a more frequent use of the spillways and opening strategies that are based on stages.

Description: Assessment of calculation methods for calcium carbonate saturation in drinking water for DIN 38404-10 compliance Drinking Water Engineering and Science, 6, 115-124, 2013 Author(s): P. J. de Moel, A. W. C. van der Helm, M. van Rijn, J. C. van Dijk, and W. G. J. van der Meer The new German standard on the calculation of calcite saturation in drinking water, DIN 38404-10, 2012 (DIN), marks a change in drinking water standardization from using simplified equations applicable for nomographs and simple calculators to using extensive chemical modeling requiring computer programs. The standard outlines the chemical modeling and presents a dataset with 10 water samples for validating used computer programs. The DIN standard, as well as the Standard Methods 2330 (SM) and NEN 6533 (NEN) for calculation of calcium carbonate saturation in drinking water were translated into chemical databases for use in PHREEQC (USGS, 2013). This novel approach gave the possibility to compare the calculations as defined in the standards with calculations using widely used chemical databases provided with PHREEQC. From this research it is concluded that the computer program PHREEQC with the developed chemical database din38404-10_2012.dat complies with the DIN standard for calculating Saturation Index (SI) and Calcite Dissolution Capacity (Calcitlösekapazität) or Calcium Carbonate Precipitation Potential (CCPP). This compliance is achieved by assuming equal values for molarity as used in DIN (obsolete) and molality as used in PHREEQC. From comparison with widely used chemical databases it is concluded that the use of molarity limits the use of DIN to a maximum temperature of 45 °C. For current practical applications in water treatment and drinking water applications, the PHREEQC database stimela.dat was developed within the Stimela platform of Delft University of Technology. This database is an extension of the chemical database phreeqc.dat and thus in compliance with SM. The database stimela.dat is also applicable for hot and boiling water, which is important in drinking water supply with regard to scaling of calcium carbonate in in-house drinking water practices. SM and NEN proved to be not accurate enough to comply with DIN, because of their simplifications. The differences in calculation results for DIN, SM and NEN illustrate the need for international unification of the standard for calcium carbonate saturation in drinking water.

Description: Cost and impact analysis of preventive and remedial measures for safe drinking water Drinking Water Engineering and Science Discussions, 6, 1-26, 2013 Author(s): M. A. Tahir and H. Rasheed Preventive measures yield much higher cost effective benefits as compared to remedial measures. To verify this hypothesis, a survey was conducted in two different regions of Rawalpindi district of Pakistan by comparing the cost on medication and mitigation expenditures for reduction in the burden of water borne diseases. Water Quality monitoring of the study areas in comparison to WHO Drinking Water Guidelines revealed the satisfactory level of physico-chemical parameters, however; significant bacteriological contamination was found at 86% of the monitored sites in Gujar Khan and 87% in Murree region. A field questionnaire was used to estimate the expenditures on disinfection and sanitation and concluded that 8.09% of total income of each family were spent by the inhabitants of the study area on medication for water borne diseases. Correlation was worked out between the rate of water related diseases ( V WRD ), unsafe drinking water ( C DW ), poor sanitation ( P S ), unhealthy personal hygiene and environment (UH PHE ). A simulation model "Victim's Rate Calculator" was developed to forecast the estimated number of victims within a population. Findings of the study verified the hypothesis that preventive measures are better choice than remedial measures due to cost benefit ratio (1 : 1.6) with a clear advantage of 60%.

Description: Natural organic matter removal by ion exchange at different positions in the drinking water treatment lane Drinking Water Engineering and Science, 6, 1-10, 2013 Author(s): A. Grefte, M. Dignum, E. R. Cornelissen, and L. C. Rietveld To guarantee a good water quality at the customers tap, natural organic matter (NOM) should be (partly) removed during drinking water treatment. The objective of this research was to improve the biological stability of the produced water by incorporating anion exchange (IEX) for NOM removal. Different placement positions of IEX in the treatment lane (IEX positioned before coagulation, before ozonation or after slow sand filtration) and two IEX configurations (MIEX ® and fluidized IEX (FIX)) were compared on water quality as well as costs. For this purpose the pre-treatment plant at Loenderveen and production plant Weesperkarspel of Waternet were used as a case study. Both, MIEX ® and FIX were able to remove NOM (mainly the HS fraction) to a high extent. NOM removal can be done efficiently before ozonation and after slow sand filtration. The biological stability, in terms of assimilable organic carbon, biofilm formation rate and dissolved organic carbon, was improved by incorporating IEX for NOM removal. The operational costs were assumed to be directly dependent of the NOM removal rate and determined the difference between the IEX positions. The total costs for IEX for the three positions were approximately equal (0.0631 € m −3 ), however the savings on following treatment processes caused a cost reduction for the IEX positions before coagulation and before ozonation compared to IEX positioned after slow sand filtration. IEX positioned before ozonation was most cost effective and improved the biological stability of the treated water.

Description: Removal of paraquat pesticide with Fenton reaction in a pilot scale water system Drinking Water Engineering and Science Discussions, 6, 233-260, 2013 Author(s): C. Oliveira, K. Gruskevica, T. Juhna, K. Tihomirova, A. Alves, and L. M. Madeira Advanced oxidation processes, such as the Fenton's reagent, are powerful methods for decontamination of different environments from recalcitrant organics. In this work it was studied the degradation of paraquat pesticide (employing the commercial product gramoxone) directly inside the pipes of a pilot scale loop system; the effect of corroded cast iron pipe and loose deposits for catalysing the process was also evaluated. Results showed that complete degradation of paraquat ([PQ] 0 = 3.9 × 10 −4 M, T = 20–30 °C, pH 0 = 3, [H 2 O 2 ] 0 = 1.5 × 10 −2 M and [Fe (II)] = 5.0 × 10 −4 M,) was achieved within 8 h, either in lab scale or in the pilot loop. Complete PQ degradation was obtained at pH 3 whereas only 30% of PQ was degraded at pH 5 during 24 h. The installation of old cast iron segments with length from 0.5 to 14 m into PVC pipe loop system had a significant positive effect on degradation rate of PQ, even without addition of iron salt; the longer the iron pipes section, the fastest was the pesticide degradation. Addition of loose deposits (mostly corrosion products composed of goethite, magnetite and a hydrated phase of FeO) also catalysed the Fenton reaction due to presence of iron in the deposits. Moreover, gradual addition of hydrogen peroxide improved gramoxone degradation and mineralization. This study showed for the first time that is possible to achieve complete degradation of pesticides in situ of pipe water system and that deposits and corroded pipes catalyse oxidation of pesticides.

Description: Study on the antibacterial activity of selected natural herbs and their application in water treatment Drinking Water Engineering and Science Discussions, 6, 199-231, 2013 Author(s): P. S. Harikumar and C. M. Manjusha The microbial contamination of water is a world-wide environmental problem. Many traditional methods are being used in various parts of the world to purify the water. According to World Health Organization, 80% of world's population living in rural areas relies on herbal traditional medicines as their primary health care. So the study on properties and uses of medicinal plants are subject to growing interests. An attempt was made to assess the antibacterial properties of certain selected herbs such as Ocimum sanctum (Krishna Tulsi), Ocimum kilimandscharicum (Karpoora Tulsi), Ocimum tenuiflorum (Ram Tulsi), Azadirachta indica (Neem), Simarouba glauca (bitterwood), Caesalpinia sappan (Pathimugam), Cuminum cyminum (Jeerakam), Vetiveria zizanioides (Ramacham), Saraca indica (Ashoka tree) and Murraya koenigii (curry leaves) against different bacteria such as total coliforms, faecal coliforms, Escherichia coli , Bacillus sp. and Serratia sp. The antibacterial activity of the plant extracts was determined by spread plate method, Kirby–Bauer disc diffusion method, most probable number (MPN) method and Petrifilm method. The shelf life of the herbal extract Ocimum sanctum (Krishna Tulsi) was also determined using a UV-visible spectrophotometer. A comparison study of the antibacterial efficiency of the three varieties of Ocimum sanctum, Ocimum kilimandscharicum and Ocimum tenuiflorum was also done. After the complete analysis of the antibacterial activity of different herbs, Ocimum sanctum , the most efficient herb, was selected and treatment methods based on the herb were developed so that it can be used conveniently in various households. Therefore Ocimum sanctum plant can be further subjected to isolation of therapeutic antimicrobial and pharmacological evaluation.

Description: Online data processing for proactive water distribution network operation Drinking Water Engineering and Science Discussions, 6, 261-290, 2013 Author(s): J. Machell, S. R. Mounce, B. Farley, and J. B. Boxall Operational benefits and efficiencies generated using prevalent water industry methods and techniques are becoming more difficult to achieve; as demonstrated by English and Welsh water companies' static position with regards the economic level of leakage. Water companies are often unaware of network incidents such as burst pipes or low pressure events until they are reported by customers; and therefore use reactive strategies to manage the effects of these events. It is apparent that new approaches need to be identified and applied to promote proactive network management if potential operational productivity and standards of service improvements are to be realised. This paper describes how measured flow and pressure data from instrumentation deployed in a water distribution network was automatically gathered, checked, analysed and presented using recently developed techniques to generate apposite information about network performance. The work demonstrated that these technologies can provide early warning, and hence additional time to that previously available, thereby creating opportunity to proactively manage a network; for example to minimise the negative impact on standards of customer service caused by unplanned events such as burst pipes. Each method, applied individually, demonstrated improvement on current industry processes. Combined application resulted in further improvements; including quicker and more localised burst main location. Future possibilities are explored, from which a vision of seamless integration between such technologies emerges to enable proactive management of distribution network events.

Description: Technical Note: Wet validation of optical tomography for drinking water discolouration studies Drinking Water Engineering and Science, 6, 55-59, 2013 Author(s): R. Floris, P. van Thienen, and H. Beverloo This paper presents a set of validation experiments for the reconstruction of a cross-sectional particle concentration field in a transparent pipe filled with a fluid using optical tomography.

Description: Development of water use scenarios as a tool for adaptation to climate change Drinking Water Engineering and Science, 6, 61-68, 2013 Author(s): R. Jacinto, M. J. Cruz, and F. D. Santos The project ADAPTACLIMA, promoted by EPAL, the largest Portuguese Water Supply Utility, aims to provide the company with an adaptation strategy in the medium and long term to reduce the vulnerability of its activities to climate change. We used the four scenarios (A1, A2, B1, B2) adopted in the Special Report Emissions Scenarios (SRES) of the IPCC (Intergovernmental Panel on Climate Change) to produce local scenarios of water use. Available population SRES for Portugal were downscaled to the study area using a linear approach. Local land use scenarios were produced using the following steps: (1) characterization of the present land use for each municipality of the study area using Corine Land Cover and adaptation of the CLC classes to those used in the SRES; (2) identification of recent tendencies in land use change for the study area; (3) identification of SRES tendencies for land use change in Europe; and (4) production of local scenarios of land use. Water use scenarios were derived considering both population and land use scenarios as well as scenarios of change in other parameters (technological developments, increases in efficiency, climate changes, or political and behavioural changes). The A2 scenario forecasts an increase in population (+16%) in the study area while the other scenarios show a reduction in the resident population (−6 to 8%). All scenarios, but especially A1, show a reduction in agricultural area and an increase in urban area. Regardless of the scenario, water use will progressively be reduced until 2100. These reductions are mainly due to increased water use efficiency and the reduction of irrigated land. The results accord with several projects modelling water use at regional and global level.

Description: Non-residential water demand model validated with extensive measurements and surveys Drinking Water Engineering and Science, 6, 99-114, 2013 Author(s): E. J. Pieterse-Quirijns, E. J. M. Blokker, E. van der Blom, and J. H. G. Vreeburg Existing Dutch guidelines for the design of the drinking water and hot water system of non-residential buildings are based on outdated assumptions on peak water demand or on unfounded assumptions on hot water demand. They generally overestimate peak demand values required for the design of an efficient and reliable water system. Recently, a procedure was developed based on the end-use model SIMDEUM to derive design-demand-equations for peak demand values of both cold and hot water during various time steps for several types and sizes of non-residential buildings, viz. offices, hotels and nursing homes. In this paper, the design-demand-equations are validated with measurements of cold and hot water patterns on a per second base and with surveys. The good correlation between the simulated water demand patterns and the measured patterns indicates that the basis of the design-demand-equations, the SIMDEUM simulated standardised buildings, is solid. Surveys were held to investigate whether the construction of the standardised buildings based on the dominant variable corresponds with practice. Surveys show that it is difficult to find relationships to equip the standardised buildings with users and appliances. However, the validation proves that with a proper estimation of the number of users and appliances in only the dominant functional room of the standardised buildings, SIMDEUM renders a realistic cold and hot water diurnal demand pattern. Furthermore, the new design-demand-equations based on these standardised buildings give a better prediction of the measured peak values for cold water flow than the existing guidelines. Moreover, the new design-demand-equations can predict hot water use well. In this paper it is illustrated that the new design-demand-equations lead to reliable and improved designs of building installations and water heater capacity, resulting in more hygienic and economical installations.

Description: Predicting the residual aluminum level in water treatment process Drinking Water Engineering and Science, 6, 39-46, 2013 Author(s): J. Tomperi, M. Pelo, and K. Leiviskä In water treatment processes, aluminum salts are widely used as coagulation chemical. High dose of aluminum has been proved to be at least a minor health risk and some evidence points out that aluminum could increase the risk of Alzheimer's disease. Thus it is important to minimize the amount of residual aluminum in drinking water and water used at food industry. In this study, the data of a water treatment plant (WTP) was analyzed and the residual aluminum in drinking water was predicted using Multiple Linear Regression (MLR) and Artificial Neural Network (ANN) models. The purpose was to find out which variables affect the amount of residual aluminum and create simple and reliable prediction models which can be used in an early warning system (EWS). Accuracy of ANN and MLR models were compared. The new nonlinear scaling method based on generalized norms and skewness was used to scale all measurement variables to range [−2...+2] before data-analysis and modeling. The effect of data pre-processing was studied by comparing prediction results to ones achieved in an earlier study. Results showed that it is possible to predict the baseline level of residual aluminum in drinking water with a simple model. Variables that affected the most the amount of residual aluminum were among others: raw water temperature, raw water KMnO 4 and PAC/KMnO 4 (Poly-Aluminum Chloride/Potassium permanganate)-ratio. The accuracies of MLR and ANN models were found to be almost the same. Study also showed that data pre-processing affects to the final prediction result.

Description: Removal and transformation of pharmaceuticals in wastewater treatment plants and constructed wetlands Drinking Water Engineering and Science, 6, 89-98, 2013 Author(s): E. Lee, S. Lee, J. Park, Y. Kim, and J. Cho Since trace organic compounds such as pharmaceuticals in surface water have been a relevant threat to drinking water supplies, in this study removal of pharmaceuticals and transformation of pharmaceuticals into metabolites were investigated in the main source of micropollutants such as WWTPs and engineered constructed wetlands. Pharmaceuticals were effectively removed by different WWTP processes and wetlands. Pharmaceutical metabolites with relatively low log D value were resulted in the low removal efficiencies compared to parent compounds with relatively high log D value, indicating the stability of metabolites. And the constructed wetlands fed with wastewater effluent were encouraged to prevent direct release of micropollutants into surface waters. Among various pharmaceuticals, different transformation pattern of ibuprofen was observed with significant formation of 1-hydroxy-ibuprofen during biological treatment in WWTP, indicating preferential biotransformation of ibuprofen. Lastly, transformation of pharmaceuticals depending on their structural position was investigated in terms of electron density, and, the electron rich C 1 = C 2 bond of carbamazepine was revealed as an initial transformation position.

Description: Development and evaluation of new behavioral indexes for a biological early warning system using Daphnia magna Drinking Water Engineering and Science Discussions, 6, 39-58, 2013 Author(s): T. Y. Jeong, J. H. Jeon, and S. D. Kim New behavioral indexes including combined index (CI), distribution index (DI), toxic index (TI), and altitude index (AI) for a biological early warning system (BEWS) were developed and evaluated using Daphnia magna in this study. The sensitivity and stability of each index were compared to evaluate the performance of the indexes through a real-time exposure test with a synthetic copper solution. The applicability of the CI to the field sample was evaluated through an effluent exposure test. The proportional relationship between toxicity level and magnitude of response was much lower in the effluent due to the complexity of water than in the copper solution. The results showed that the CI was most sensitive among the three indexes, while the DI was confirmed as the most useful index among the individual indexes. The combined index (CI) shows not only sensitivity but also stability in normal conditions below the statistically significant threshold ( p 〈 0.01), whereas the individual indexes displayed unstable index values in normal conditions ( p 〉 0.01). The CI improved performance of the BEWS in terms of sensitivity and stability, and it was confirmed as the higher correlation coefficient between the magnitude of the index and the toxicity level of the water sample.

Description: Flowmeter data validation and reconstruction methodology to provide the annual efficiency of a water transport network: the ATLL case study in Catalonia Drinking Water Engineering and Science Discussions, 6, 79-95, 2013 Author(s): J. Quevedo, J. Pascual, V. Puig, J. Saludes, R. Sarrate, S. Espin, and J. Roquet The object of this paper is to provide a flowmeter data validation/reconstruction methodology that determines the annual economic and hydraulic efficiency of a water transport network. In this paper, the case of Aigües Ter Llobregat (ATLL) company, that is in charge of managing the 80% of the overall water transport network in Catalonia (Spain), will be used for illustrating purposes. The economic/hydraulic network efficiency is based on the daily data set collected by the company using about 200 flowmeters of the network. The data collected using these sensors are used by the remote control and information storage systems and they are stored in a relational database. All the information provided by ATLL is analyzed to detect inconsistent data using an automatic data validation method deployed in parallel with the evaluation of the network efficiency. As a result of the validation process, corrections of flow measurements and of the volume of billed water are introduced. The results of the ATLL water transport network obtained during year 2010 will be used to illustrate the approach proposed in this paper.

Description: The object of this paper is to provide a flowmeter data validation/reconstruction methodology that determines the annual economic and hydraulic efficiency of a water transport network. In this paper, the case of Aigües Ter Llobregat (ATLL) company, that is in charge of managing the 80% of the overall water transport network in Catalonia (Spain), will be used for illustrating purposes. The economic/hydraulic network efficiency is based on the daily data set collected by the company using about 200 flowmeters of the network. The data collected using these sensors are used by the remote control and information storage systems and they are stored in a relational database. All the information provided by ATLL is analyzed to detect inconsistent data using an automatic data validation method deployed in parallel with the evaluation of the network efficiency. As a result of the validation process, corrections of flow measurements and of the volume of billed water are introduced. The results of the ATLL water transport network obtained during year 2010 will be used to illustrate the approach proposed in this paper.

Description: Preventive measures yield much higher cost effective benefits as compared to remedial measures. To verify this hypothesis, a survey was conducted in two different regions of Rawalpindi district of Pakistan by comparing the cost on medication and mitigation expenditures for reduction in the burden of water borne diseases. Water Quality monitoring of the study areas in comparison to WHO Drinking Water Guidelines revealed the satisfactory level of physico-chemical parameters, however; significant bacteriological contamination was found at 86% of the monitored sites in Gujar Khan and 87% in Murree region. A field questionnaire was used to estimate the expenditures on disinfection and sanitation and concluded that 8.09% of total income of each family were spent by the inhabitants of the study area on medication for water borne diseases. Correlation was worked out between the rate of water related diseases (VWRD), unsafe drinking water (CDW), poor sanitation (PS), unhealthy personal hygiene and environment (UHPHE). A simulation model "Victim's Rate Calculator" was developed to forecast the estimated number of victims within a population. Findings of the study verified the hypothesis that preventive measures are better choice than remedial measures due to cost benefit ratio (1 : 1.6) with a clear advantage of 60%.

Description: In water supply systems, a considerable amount of apparent loss is caused by meter under-registration. Water meters are subject to intrinsic systemic error depending on the actual flow rates passing through them. Furthermore, the moving parts of the meter are subject to wear and tear that progressively reduce meter accuracy. The increase in systemic error is especially evident at low flow rates because of growing friction in the rotating mechanism, which requires a higher flow to start the meter (starting flow). The aim of this paper is to experimentally investigate metering error in an attempt to find a direct link between meter age, network pressure and apparent losses caused by the inability of the meter to accurately register the volume passing though it at low flow rates. The study was performed through laboratory experiments in which worn-out water meters were tested using a test bench. The results of the laboratory experiments show that ageing and pressure are both relevant parameters for determining meter starting flow. These results were then applied to assess the effects on apparent losses of the age of the meter, varying pressure values upstream of the meter (the pressure in the network where the meter is installed) and different patterns of flow rates passing through the device (the consumption pattern of the user). The presented results are useful for understanding the effects of operating conditions on water meter under-registration, which can aid water managers in implementing effective replacement campaigns.

Description: In water treatment processes, aluminum salts are widely used as coagulation chemical. High dose of aluminum has been proved to be at least a minor health risk and some evidence points out that aluminum could increase the risk of Alzheimer's disease. Thus it is important to minimize the amount of residual aluminum in drinking water and water used at food industry. In this study, the data of a water treatment plant (WTP) was analyzed and the residual aluminum in drinking water was predicted using Multiple Linear Regression (MLR) and Artificial Neural Network (ANN) models. The purpose was to find out which variables affect the amount of residual aluminum and create simple and reliable prediction models which can be used in an early warning system (EWS). Accuracy of ANN and MLR models were compared. The new nonlinear scaling method based on generalized norms and skewness was used to scale all measurement variables to range [−2...+2] before data-analysis and modeling. The effect of data pre-processing was studied by comparing prediction results to ones achieved in an earlier study. Results showed that it is possible to predict the baseline level of residual aluminum in drinking water with a simple model. Variables that affected the most the amount of residual aluminum were among others: raw water temperature, raw water KMnO4 and PAC/KMnO4 (Poly-Aluminum Chloride/Potassium permanganate)-ratio. The accuracies of MLR and ANN models were found to be almost the same. Study also showed that data pre-processing affects to the final prediction result.

Description: Financial resources are crucial to improve existing urban drinking water supply in developing countries typically characterized by low cost recovery rates and high and rapidly growing demand for more reliable services. This study examines the willingness to pay for improved urban drinking water supply employing a choice model (CM) in an urban context in Ethiopia, Hawassa, with a household survey of 170 respondents. The design of the choice model allows the estimation of the values of two attributes of urban drinking water service (extra day water delivery per week and safer water). The findings indicate that households are willing to pay up to 60% extra for improved levels of water supply over and above their current water bill. Especially those households living in the poorest part of the city with the lowest service levels demonstrate that they are willing to pay more despite significant income constraints they are facing. Women value the improvement of water quality most, while a significant effect is found for averting behavior and expenditures. The estimated economic values can be used in policy appraisals of investment decisions.

Description: Since trace organic compounds such as pharmaceuticals in surface water have been a relevant threat to drinking water supplies, in this study removal of pharmaceuticals and transformation of pharmaceuticals into metabolites were investigated in the main source of micropollutants such as WWTPs and engineered constructed wetlands. Pharmaceuticals were effectively removed by different WWTP processes and wetlands. Pharmaceutical metabolites with relatively low log D value were resulted in the low removal efficiencies compared to parent compounds with relatively high log D value, indicating the stability of metabolites. And the constructed wetlands fed with wastewater effluent were encouraged to prevent direct release of micropollutants into surface waters. Among various pharmaceuticals, different transformation pattern of ibuprofen was observed with significant formation of 1-hydroxy-ibuprofen during biological treatment in WWTP, indicating preferential biotransformation of ibuprofen. Lastly, transformation of pharmaceuticals depending on their structural position was investigated in terms of electron density, and, the electron rich C1 = C2 bond of carbamazepine was revealed as an initial transformation position.

Description: This study reports the occurrences of organochlorine pesticides (OCPs) in the Ganga river basin covering 3 states, i.e., Uttarakhand, Uttar Pradesh and Bihar comprising 72% of total river stretch consisting of 82 sampling points covered through 3 sampling campaigns. Samples were monitored for 16 major OCPs, including hexachlorocyclohexanes (HCHs), Endosulfan group, Aldrin group, DDTs and Heptachlor group pesticides. The results showed the ng L−1 levels contamination of OCPs in all the stretches sampled during these campaigns. The results also revealed that different types of OCPs were dominating in different stretches in accordance with the land use practices and agricultural runoff generated from those stretches. HCHs were most frequently detected (detection rate = 75%) in mountainous stretch; Endosulfans were prominent in UP (detection rate = 75%) stretch while in BR stretch Aldrin group pesticides were paramount (detection rate = 34%). Source apportionment of the OCP's revealed that in the upper reaches of the Ganges i.e., in the state of Uttarakhand, the glacial melt may be responsible for the presence of OCP's. In the lower reaches, intensive agriculture and industrial activities may be significantly contributing these pesticides. The samples from tributaries of Ganga river were found to contain higher numbers of pesticides as well as higher concentrations. The maximum total pesticide concentration in an individual sample during these sampling campaigns was found in the Son river sample (0.17 μg L−1, Location: Koilwar, Bhojpur, Bihar).

Description: Existing Dutch guidelines for the design of the drinking water and hot water system of non-residential buildings are based on outdated assumptions on peak water demand or on unfounded assumptions on hot water demand. They generally overestimate peak demand values required for the design of an efficient and reliable water system. Recently, a procedure was developed based on the end-use model SIMDEUM to derive design-demand-equations for peak demand values of both cold and hot water during various time steps for several types and sizes of non-residential buildings, viz. offices, hotels and nursing homes. In this paper, the design-demand-equations are validated with measurements of cold and hot water patterns on a per second base and with surveys. The good correlation between the simulated water demand patterns and the measured patterns indicates that the basis of the design-demand-equations, the SIMDEUM simulated standardised buildings, is solid. Surveys were held to investigate whether the construction of the standardised buildings based on the dominant variable corresponds with practice. Surveys show that it is difficult to find relationships to equip the standardised buildings with users and appliances. However, the validation proves that with a proper estimation of the number of users and appliances in only the dominant functional room of the standardised buildings, SIMDEUM renders a realistic cold and hot water diurnal demand pattern. Furthermore, the new design-demand-equations based on these standardised buildings give a better prediction of the measured peak values for cold water flow than the existing guidelines. Moreover, the new design-demand-equations can predict hot water use well. In this paper it is illustrated that the new design-demand-equations lead to reliable and improved designs of building installations and water heater capacity, resulting in more hygienic and economical installations.

Description: This paper extends the analysis concerning the importance in numerical models of unsteady friction and viscoelasticity to transients in plastic pipes with an external flow due to a leak. In fact recently such a benchmarking analysis has been executed for the cases of a constant diameter pipe (Duan et al., 2010), a pipe with a partially closed in-line valve (Meniconi et al., 2012a), and a pipe with cross-section changes in series (Meniconi et al., 2012b). Tests are based on laboratory experiments carried out at the Water Engineering Laboratory (WEL) of the University of Perugia, Italy, and the use of different numerical models. The results show that it is crucial to take into account the viscoelasticity to simulate the main characteristics of the examined transients.

Description: To explore the possibility of fluoride toxicity, 747 water samples were collected from surface water and groundwater sources of 16 major cities of Pakistan, adopting a uniform sampling design with distribution of samples: Lahore (79), Kasur (46), Faisalabad (30), Khushab (50), Chakwal (51), Mianwali (30), Jhelum (53), Bahawalpur (60), Karachi (60), Mirpur Khas (55), Peshawar (38), Risalpur (35), Quetta (81), Ziarat (21), Loralai (21), and Mastung (37). Comparison of analytical findings with WHO Guidelines of Drinking Water for Fluoride (i.e., 1.5 ppm) has concluded that 16% of the monitored water sources have fluoride concentration beyond the permissible safe limit of 1.5 mg L−1 falling in the concentration range of 1.6–25 mg L−1. The highest fluoride contamination (22%) is detected in the Balochistan province followed by 19% in Punjab province. Comparatively higher fluoride levels of 〉 20% in the groundwater sources like hand pumps supported the possibility of increased groundwater contamination as excessive fluoride concentrations are expected to come from calcium-poor aquifers and in areas where fluoride-bearing minerals are common or where cation exchange of sodium for calcium occurs. Field observations have also indicated the prevalence of fluoride-associated health implications in the study areas with excessive fluoride in water sources. Findings of this study have provided bidirectional vision for the epidemiological investigations as well as to mitigate the issues in the affected vicinities of fluoride-rich areas.

Description: To guarantee a good water quality at the customers tap, natural organic matter (NOM) should be (partly) removed during drinking water treatment. The objective of this research was to improve the biological stability of the produced water by incorporating anion exchange (IEX) for NOM removal. Different placement positions of IEX in the treatment lane (IEX positioned before coagulation, before ozonation or after slow sand filtration) and two IEX configurations (MIEX® and fluidized IEX (FIX)) were compared on water quality as well as costs. For this purpose the pre-treatment plant at Loenderveen and production plant Weesperkarspel of Waternet were used as a case study. Both, MIEX® and FIX were able to remove NOM (mainly the HS fraction) to a high extent. NOM removal can be done efficiently before ozonation and after slow sand filtration. The biological stability, in terms of assimilable organic carbon, biofilm formation rate and dissolved organic carbon, was improved by incorporating IEX for NOM removal. The operational costs were assumed to be directly dependent of the NOM removal rate and determined the difference between the IEX positions. The total costs for IEX for the three positions were approximately equal (0.0631 € m−3), however the savings on following treatment processes caused a cost reduction for the IEX positions before coagulation and before ozonation compared to IEX positioned after slow sand filtration. IEX positioned before ozonation was most cost effective and improved the biological stability of the treated water.

Description: This paper presents a set of validation experiments for the reconstruction of a cross-sectional particle concentration field in a transparent pipe filled with a fluid using optical tomography.

Description: The application of membrane technology in water and wastewater treatment is increasing due to stringent water quality standards. Nanofiltration (NF) is one of the widely used membrane processes for water and wastewater treatment in addition to other applications such as desalination. NF has replaced reverse osmosis (RO) membranes in many applications due to lower energy consumption and higher flux rates. This paper briefly reviews the application of NF for water and wastewater treatment including fundamentals, mechanisms, fouling challenges and their controls.

Description: The project ADAPTACLIMA, promoted by EPAL, the largest Portuguese Water Supply Utility, aims to provide the company with an adaptation strategy in the medium and long term to reduce the vulnerability of its activities to climate change. We used the four scenarios (A1, A2, B1, B2) adopted in the Special Report Emissions Scenarios (SRES) of the IPCC (Intergovernmental Panel on Climate Change) to produce local scenarios of water use. Available population SRES for Portugal were downscaled to the study area using a linear approach. Local land use scenarios were produced using the following steps: (1) characterization of the present land use for each municipality of the study area using Corine Land Cover and adaptation of the CLC classes to those used in the SRES; (2) identification of recent tendencies in land use change for the study area; (3) identification of SRES tendencies for land use change in Europe; and (4) production of local scenarios of land use. Water use scenarios were derived considering both population and land use scenarios as well as scenarios of change in other parameters (technological developments, increases in efficiency, climate changes, or political and behavioural changes). The A2 scenario forecasts an increase in population (+16%) in the study area while the other scenarios show a reduction in the resident population (−6 to 8%). All scenarios, but especially A1, show a reduction in agricultural area and an increase in urban area. Regardless of the scenario, water use will progressively be reduced until 2100. These reductions are mainly due to increased water use efficiency and the reduction of irrigated land. The results accord with several projects modelling water use at regional and global level.

Description: The new German standard on the calculation of calcite saturation in drinking water, DIN 38404-10, 2012 (DIN), marks a change in drinking water standardization from using simplified equations applicable for nomographs and simple calculators to using extensive chemical modeling requiring computer programs. The standard outlines the chemical modeling and presents a dataset with 10 water samples for validating used computer programs. The DIN standard, as well as the Standard Methods 2330 (SM) and NEN 6533 (NEN) for calculation of calcium carbonate saturation in drinking water were translated into chemical databases for use in PHREEQC (USGS, 2013). This novel approach gave the possibility to compare the calculations as defined in the standards with calculations using widely used chemical databases provided with PHREEQC. From this research it is concluded that the computer program PHREEQC with the developed chemical database din38404-10_2012.dat complies with the DIN standard for calculating Saturation Index (SI) and Calcite Dissolution Capacity (Calcitlösekapazität) or Calcium Carbonate Precipitation Potential (CCPP). This compliance is achieved by assuming equal values for molarity as used in DIN (obsolete) and molality as used in PHREEQC. From comparison with widely used chemical databases it is concluded that the use of molarity limits the use of DIN to a maximum temperature of 45 °C. For current practical applications in water treatment and drinking water applications, the PHREEQC database stimela.dat was developed within the Stimela platform of Delft University of Technology. This database is an extension of the chemical database phreeqc.dat and thus in compliance with SM. The database stimela.dat is also applicable for hot and boiling water, which is important in drinking water supply with regard to scaling of calcium carbonate in in-house drinking water practices. SM and NEN proved to be not accurate enough to comply with DIN, because of their simplifications. The differences in calculation results for DIN, SM and NEN illustrate the need for international unification of the standard for calcium carbonate saturation in drinking water.

Description: Sporadic detection of live (viable) Escherichia coli in drinking water and biofilm with molecular methods but not with standard plate counts has raised concerns about the reliability of this indicator in the surveillance of drinking water safety. The aim of this study was to determine spatial distribution of different viability forms of E. coli in a drinking water distribution system which complies with European Drinking Water Directive (98/83/EC). For two years coupons (two week old) and pre-concentrated (100 times with ultrafilters) water samples were collected after treatment plants and from four sites in the distribution network at several distances. The samples were analyzed for total, viable (able to divide as DVC-FISH positive) and cultivable E. coli. The results showed that low numbers of E. coli enters the distribution sytem from the treatment plants and tend to accumulate in the biofilm of water distribution system. Almost all of the samples contained metabolically active E. coli in the range of 1 to 50 cells per litre or cm2 which represented approximately 53% of all E. coli detected. The amount of viable E. coli significantly increased into the network irrespective of the season. The study has shown that DVC-FISH method in combination with water pre-concentration and biofilm sampling allows to better understand the behaviour of E. coli in water distribution networks, thus, it provides new evidences for water safety control.

Description: The microbial contamination of water is a world-wide environmental problem. Many traditional methods are being used in various parts of the world to purify the water. According to World Health Organization, 80% of world's population living in rural areas relies on herbal traditional medicines as their primary health care. So the study on properties and uses of medicinal plants are subject to growing interests. An attempt was made to assess the antibacterial properties of certain selected herbs such as Ocimum sanctum (Krishna Tulsi), Ocimum kilimandscharicum (Karpoora Tulsi), Ocimum tenuiflorum (Ram Tulsi), Azadirachta indica (Neem), Simarouba glauca (bitterwood), Caesalpinia sappan (Pathimugam), Cuminum cyminum (Jeerakam), Vetiveria zizanioides (Ramacham), Saraca indica (Ashoka tree) and Murraya koenigii (curry leaves) against different bacteria such as total coliforms, faecal coliforms, Escherichia coli, Bacillus sp. and Serratia sp. The antibacterial activity of the plant extracts was determined by spread plate method, Kirby–Bauer disc diffusion method, most probable number (MPN) method and Petrifilm method. The shelf life of the herbal extract Ocimum sanctum (Krishna Tulsi) was also determined using a UV-visible spectrophotometer. A comparison study of the antibacterial efficiency of the three varieties of Ocimum sanctum, Ocimum kilimandscharicum and Ocimum tenuiflorum was also done. After the complete analysis of the antibacterial activity of different herbs, Ocimum sanctum, the most efficient herb, was selected and treatment methods based on the herb were developed so that it can be used conveniently in various households. Therefore Ocimum sanctum plant can be further subjected to isolation of therapeutic antimicrobial and pharmacological evaluation.

Description: The objective of this paper was to describe the impact of climate change on the Mississippi River flood hazard in the New Orleans area. This city has a unique flood risk management challenge, heavily influenced by climate change, since it faces flood hazards from multiple geographical locations (e.g. Lake Pontchartrain and Mississippi River) and multiple sources (hurricane, river, rainfall). Also the low elevation and significant subsidence rate of the Greater New Orleans area poses a high risk and challenges the water management of this urban area. Its vulnerability to flooding became dramatically apparent during Hurricane Katrina in 2005 with huge economic losses and a large number of casualties. A SOBEK Rural 1DFLOW model was set up to simulate the general hydrodynamics. This model included the two important spillways that are operated during high flow conditions. A weighted multi-criteria calibration procedure was performed to calibrate the model for high flows. Validation for floods in 2011 indicated a reasonable performance for high flows and clearly demonstrated the influence of the spillways. 32 different scenarios were defined which included the relatively large sea level rise and the changing discharge regime that is expected due to climate change. The impact of these scenarios on the water levels near New Orleans were analysed by the hydrodynamic model. Results showed that during high flows New Orleans will not be affected by varying discharge regimes, since the presence of the spillways ensures a constant discharge through the city. In contrary, sea level rise is expected to push water levels upwards. The effect of sea level rise will be noticeable even more than 470 km upstream. Climate change impacts necessitate a more frequent use of the spillways and opening strategies that are based on stages.

Description: In Germany, many hydro-geothermal plants have been constructed in recent years, primarily in the region of Munich. As the host formation here mainly consists of carbonates, nearly all recently drilled wells have been acidized in order to improve the well yield. In this study, the effectiveness of these acid treatments is analyzed with respect to the amount of acid used and the number of acid treatments carried out per well. The results show that the first acid treatment has the largest effect, while subsequent acidizing improves the well only marginally. Data also indicate that continued acidizing can lead to degradation of the well. These findings may not only be important for geothermal installations in Germany but also for projects, for example, in Austria, France or China where geothermal energy is produced from carbonate formations as well.