bluuebunny/crossref_metadata_2025_split huggingface dataset:
Perspective: Positive experiences from Africa in water, sanitation and hygiene
Authors: Lane Jon 
Published: May 2018

Nowhere in the world is poverty more visible, more destructive and more pervasive than in Africa. Too often, Africa is associated with stories of failure and pessimism, of wars and famines, floods and unrest. Africa appears to be slipping back on many development indicators, even as other parts of the world move ahead.
In 2003, however, there are prospects of achieving progress in water, sanitation and hygiene in Africa. Across the continent, there is a strong sense of the need for peace, democracy and co-operation. Through the Highly Indebted Poor Countries initiative, industrialised countries are finally proposing to write off a significant part of the debt into which the poorest countries have fallen. Many African countries have written Poverty Reduction Strategy Papers, which give clarity and direction to the development work in those countries. Within the water sector itself, the African Ministerial Conference on Water (AMCOW) has been formed to share ideas and lessons and to provide mutual support and active direction. Recent meetings, especially the World Summit on Sustainable Development (August 2002), are giving fresh political impetus to this work.
This paper suggests five priorities for achieving the water and sanitation Millennium Development Goals in Africa. It relates them to practical examples of inspiring and positive initiatives in water and sanitation from across the continent. These examples have worked, or have the potential to work, at a large scale, are demonstrably sustainable, and do not benefit from too many unique local conditions. These characteristics enable the lessons from these examples to be useful for other people in, and indeed outside, Africa.
Water in the economy of Tamil Nadu, India: more flexible water allocation policies offer a possible way out of water-induced economic stagnation and will be good for the environment and the poor
Authors: Bhatia Ramesh , Briscoe John , Malik R. P. S. , Miller Lindy , Misra Smita , Palainisami K. , Harshadeep N. 
Published: May 2018

The state of Tamil Nadu, India, is in the grips of a water crisis, with demand far outstripping supply. As the economy of the state grows, this crisis is going to become ever more serious. To date the focus of state water policy has been on trying to augment supplies, from within the state (even from desalinization) and from neighboring states. In addition, the water use is regulated in a way that does not encourage the highest value uses. International experience shows that supply-side measures must be complemented by demand-side measures and that practice must move away from fixed, command-and-control allocation policies towards flexible allocation mechanisms, which facilitate the voluntary movement of water from low to high-value uses.
This study addresses the question of whether such a change in allocation policies is worth doing. It addresses this question by developing optimization models for each of the 17 river basins in Tamil Nadu (including an assessment of the economic value of water in different end-uses – agriculture, domestic and industry), then using an input–output model embedded in a social accounting matrix (SAM), to assess the impact of these changes on the state economy and on different rural and urban employment groups.
The results suggest that a shift to a flexible water allocation system would bring major environmental, economic and social benefits to the state. Compared with the current “fixed sectoral allocation” policy, a flexible allocation policy would, in 2020, result in 15% less overall water used; 24% less water pumped from aquifers; 20% higher state income; with all strata, rich and poor, benefiting similarly, with one important exception, that of agricultural laborers.
The use of nanofiltration for the removal of pesticides from groundwater: an evaluation
Authors: Van der Bruggen B. , Everaert K. , Wilms D. , Vandecasteele C. 
Published: May 2018

This study explores the combined removal of four pesticides (atrazine, simazine, diuron, isoproturon) and hardness from groundwater with nanofiltration (NF). Four NF membranes were used: NF45 and NF70 (Dow/FilmTec), and UTC-20 and UTC-60 (Toray Ind. Inc.). Each pesticide was added to groundwater samples in a concentration of 1 μg/l, representative for contaminated sources. For the determination of pesticides in such low concentrations, an analytical method using solid-phase extraction and high performance liquid chromatography was elaborated.
The retentions with NF were compared and explained by means of molecular size and dipole moment. Molecular size, expressed as an effective diameter representing the projection of the molecule on the membrane surface, was calculated by determining the energetically most favourable molecular configuration. The largest molecules had the highest retentions, when all other properties are comparable. A high dipole moment decreases retentions because of charge interactions with the membrane.
The hardness retentions were high. For drinking water production, it might be necessary to add hardness after filtration.
The groundwater flux was approximately 5% lower compared to the distilled water flux. This relatively small flux decline indicates pore blocking due to adsorption in the membrane pores. The flux decline was proved reversible; no membrane fouling occurred.
Heavy metals removal from wastewaters of phosphoric acid production: a comparison of hybrid liquid membrane (HLM) and aqueous hybrid liquid membrane (AHLM) technologies
Authors: Kislik V. , Eyal A. 
Published: May 2018

Selective removal of heavy metal ions from industrial wet-process phosphoric acid (WPA) was studied, using the two liquid membrane systems: Hybrid Liquid Membrane (HLM) and Aqueous Hybrid Liquid Membrane (AHLM). Monothiophosphinic acid (Cyanex 302) in kerosene (for the HLM) and Polyvinylsulfonic acid (PVSA) aqueous solution (for the AHLM) were used as a liquid membrane (LM), separated from the feed and strip streams by neutral or cation-exchange membranes.
On application of the HLM separation system, the permeation from the feed to the strip phase followed the selectivity sequence: Zn &gt;&gt; Cd &gt; Cu with all types of membranes used. Results show that the selective separation of Cd and Zn from the WPA may be achieved by the HLM with cation-exchange membranes, using a single set-up installation at continuous processing. Copper is accumulated in the Cyanex 302, poisoning the carrier. So, this carrier and HCl as a strip solution can not be recommended for the HLM processing of WPA.
Using the AHLM separation system, heavy metals such as cadmium and copper, were successfully recovered from the WPA: average fluxes (in mol/m2sec) to the strip phase were 3.7 × 10-7 and 6.7 × 10-7. Satisfactory dynamic selectivity to copper (≈16) was found. The transfer of iron and zinc species to the strip phase was below detection levels during the 144 hrs of the AHLM experiment. Contamination of the feed and strip solutions by PVSA was not observed during the 500 hrs of processing. The membranes were completely regenerable and used repeatedly.
In comparison with the HLM and other liquid membrane systems, the AHLM can potentially provide many operational, economic and environmental advantages, some of them being higher transport rates, low carrier losses and low contamination of the feed and strip solutions by water-soluble polymers, long membrane lifetime, ambient temperature, low energy requirements and chemical consumption, no special requirements for membrane resistance in organic solvents, and fewer limitations on the variability of membrane pore sizes, etc.
Measuring up: do you have a scorecard?
Authors: Johnson K. 
Published: May 2018

Performance measurement can be an effective tool in driving organization improvement to enable your utility to become more competitive, or improve customer satisfaction. WERF Project #99-WWF-7, Developing and Implementing a Performance Measurement System, is developing performance measurement systems by investigating a number of “best practices” in other industries and implementing selected practices at various water/wastewater utilities nationwide to determine how these practices can be adapted and applied. This joint WERF/AWWARF research project has been underway since mid-1999 to provide methods and tools that enable the utility to develop and implement a performance measurement system based on a demonstrated, proven approach. The Volume I Report summarizes the secondary research and project approach.
Well designed, properly implemented performance measurement systems can enable utilities to achieve new levels of performance in terms of efficiency, quality, and effectiveness. Interest in performance measurement is increasing in all competitive businesses and industries today, and has been advanced through concepts such as the Balanced Scorecard. Utilities can employ these same concepts and learn “best practices” from other industries' experiences.
While a performance measurement system alone does not improve performance or make a utility competitive, when combined with an appropriate business strategy and performance improvement initiatives, it can drive a cycle of change. A successful performance measurement system combines a holistic approach around improved business practices and effective human/organizational strategies in addition to actual performance information for operational decision-making.
Assessing socio-cultural aspects of sustainable urban water systems - the case of Hammarby Sjöstad
Authors: Söderberg H. , Åberg H. 
Published: May 2018

The Swedish national research programme “Sustainable Urban Water Management” aims to analyse and assess the sustainability of urban water systems (UWS) covering a range of perspectives. This paper will concentrate on development of tools to assess organisational and household related aspects, being an area with a particular need of development. Incorporated in our definition of UWS, is the condition that the functioning within the system is critical for sustainability as such and three sub-systems are distinguished: households, organisation and technical structure. A point of departure is that functional fit between the sub-systems needs to be high in order to create sustainable UWS.
Organisational capacity, adaptability, motivation, opportunity and ability are used as criteria for comparison of two different technical structures. We can conclude that no straight answer to the question which system to prefer emerge - which is most often the case in reality. The two systems are high on some sub-criteria and low on others. With a combination of internal systems analysis, like this, and impact assessments, it is possible to both increase the quality of the impact assessments and manage to make analysis of organisations and households within their own frames of logic.
Mathematical analysis of a batch electrocoagulation reactor
Authors: Holt P.K. , Barton G.W. , Mitchell C.A. 
Published: May 2018

Electrocoagulation treats water by delivering coagulant from a sacrificial anode (aluminium) in an electrochemical cell. Hydrogen is evolved from the inert cathode. In the batch electrocoagulation reactor numerous interactions occur with settling and flotation identified as the dominant removal paths. Current determines both coagulant dosage and bubble production rate. The bubbles influence the mixing, and hence mass diffusion within the reactor. Rate of flotation and settling were experimentally determined for currents 0.25-2.0 A and pollutant loading 0.1-1.7 g/L. The performance of the electrocoagulation reactor was quantified by analysis of experimental results.
First-order ordinary differential equations were developed to describe the pollutant's settling and flotation behaviour. Kinetic rate constants were calculated considering this pair of irreversible reactions. At low current (0.25A), sedimentation dominates with slow release of coagulant and gentle agitation provided by low bubble production. Removal is slow and hence the low rate constants calculated were appropriate. At high currents (1.0 and 2.0 A) faster removal occurs due to greater bubble density. This resulted in greater mass floated to the surface and higher rate constants were observed. Thus the developed rate equations successfully quantified the reactor's performance over a variety of conditions.
Method for evaluating antiscalants, as applied to the treatment of water from the River Oise
Authors: Plottu-Pecheux A. , Houssais B. , Democrate C. , Gatel D. , Parron C. , Cavard J. 
Published: May 2018

Nanofiltration, used in the Méry-sur-Oise water treatment plant (90 MGD) provides a softened water with a low organic matter content from which micropollutants and microorganisms have been removed. The experience acquired on the site since 1992 has revealed that the use of a crystal formation inhibitor is essential to slow down the clogging of the nanofiltration membranes, essentially on the third stage. Given the complexity of the action of the antiscalants (threshold effect, metal ion sequestration capacity, particle dispersion capacity), it is difficult to theoretically define the type of product to be used and its optimal dosing level. In addition to laboratories or modelling studies, pilot experiments are needed to assess antiscalants and optimise their doses. Nanofiltration cycles being long (1-2 months), it is nevertheless difficult to compare results of cycles, and the objective of the project was to develop a methodology for sequestering agent testing.
To carry out strictly comparative studies of commercially available products as well as studies using the same product but at several different dosage levels, a pilot unit comprising three parallel nanofiltration trains was built. The pilot unit is fed with 2nd stage concentrate, produced without sequestering agent, and each trains has its own separate antiscalant injection point. The first cycle aimed to provide answers to the following: (i) choice of the antiscalant best adapted to the treatment of water from the river Oise, (ii) identification of the clogging agents, (iii) the efficiency of the chemical regeneration procedure.
A production cycle using the same antiscalant at three different doses (0, 1 and 3 g.m-3) demonstrated that this product acted through a threshold effect. Analysing the cleaning waters provided further information on the type of clogging agents deposited on the membrane. Although for all the cycles the overall nature of the clogging is identical, essentially composed of organic matter and mineral elements (calcium, phosphorus, aluminium, etc.). The similarity of the water permeability and salt rejection at the beginning of two consecutive cycles tends to demonstrate that the chemical regeneration procedure (caustic soda/citric acid) is efficient.
Minimum performance standards for showerheads in Australia: the benefits and the barriers
Authors: Day D. , White S. 
Published: May 2018

This paper discusses the potential merits and opportunities of introducing national minimum performance standards (MPS) for water efficient appliances, in particular showerheads. At a national level the introduction of MPS for showerheads by 2005 is expected to result in a reduction in the demand for water by over 79 GL/annum by 2015. The reduction in energy consumption associated with reduced water heating needs by water efficient showerheads is 7.7 million GJ/annum, while greenhouse gas emissions will be reduced by 1.3 million tonnes CO2/annum, by 2015.
This initiative will generate benefits to an array of stakeholders. These benefits include: increased allocation of water for environmental flows, reduced demand on groundwater sources, reduced wastewater flows and associated pollution, and financial benefits to water utilities, particularly if the utility is experiencing water supply or wastewater treatment constraints. Regulation will also protect the investment (estimated to be of the order of $16 million) that a number of water utilities are making in incentive and retrofit programs.
The most effective form of regulation to achieve the greatest outcomes in terms of reducing water and energy consumption and greenhouse gas emissions is a regulation that controls the supply of showerheads on the basis of flow rate. The MPS being proposed is 9 L/minute, and regulation would involve mandatory labelling of showerheads and compliance with the AAA-rating. The legislative options and challenge of introducing such a requirement within the current regulatory environment are discussed.
Defining the conservation potential for San Francisco's 28 wholesale customers
Authors: Levin E. , Carlin M. , Maddaus W.O. , Sandkulla N. 
Published: May 2018

This paper documents the methodology and results of a comprehensive water demand and conservation study conducted in 2003 and 2004 under the direction of the San Francisco Public Utilities Commission (SFPUC) in conjunction with its 28 wholesale customers. These customers are represented by the Bay Area Water Supply and Conservation Agency (BAWSCA). The SFPUC supplies water to about 1.6 million people within the San Francisco Bay Area plus about 700,000 within the City of San Francisco itself.
A detailed benefit-cost analysis was conducted using the Demand Side Management Least-Cost Planning Decision Support System (DSS) model for 32 conservation measures using the individual customers' DSS model. Thirty-year water savings, benefit–cost ratios, and the cost of water saved were computed for each measure.
Based on compiling the results from the individual customer demand models, it was found that the current plumbing and appliance codes would reduce overall 2030 water demand by 7.8% and that packages of additional water conservation measures could reduce demands by an additional 2–6%, depending upon the level of conservation implemented. Overall, the study represents one of the largest water demand and conservation evaluation projects undertaken in the United States.
Ozonation of Aromatic Compounds pH-Dependence
Authors: Gilbert E 
Published: May 2018

The ozonation of 2-nitro-p-cresol and p-toluenesulfonic acid (c = 1 mmole/l, ozone dose 10 mg O3/min l) in aqueous solution as a function of the pH-value (pH = 2,5 - 10,5) was investigated. At pH = 2,5 the reaction products of 2-nitro-p-cresol are measured quantitatively over the run of the reaction.
The results show that the elimination rates for the initial compounds and the mineralization of the heterogroups increase with the pH value. On account of this result the spectrum of oxidation products is different after 90 % elimination of the initial compound as a function of pH. The values of DOC-and COD-elimination increase with increasing pH-value.
Although the ozone absorption is better in the basic range one finds that 1,6 - 2,2 mg O3/mg ∆ COD are required in the basic range (pH 10), but only 1,1 mg O3/mg ∆3 COD in the acid range (pH 3).
The Elimination of Mineral Micropollutants
Authors: Regnier B , Goblet C , Genot J , Masschelein W J 
Published: May 2018

Mineral micropollutants in waste waters and drinking water are essentially composed of heavy metal salts. Their elimination, when present in trace quantities, is discussed in this paper.
The techniques, which water treatment facilities can use, necessitate preclarification in open basins (efficiency varying between 20 and 90%), elimination by filtration, with efficiencies depending largely on preoxidation but particularly on coagulation-precipitation and related techniques. Our investigations, as well as certain literature data, demonstrate the predominating importance of contact between water and sludges in decanters-clarificators. Thus, Jar tests often yield only a poorly representative result of the elimination of heavy metals by coagulation-flocculation-decantation. As to the use of aluminium sulphate, for example, the elimination rates mentioned relating to the elimination rate or % removal in laboratory experiments, in pilot tests with sludge beds and in treatment plants respectively are as follows: Fe: 100, 95, 100; Mn: 4, 38, 97; Cu: 91, 83, 85; Cr: 29, 8, 83; Cd: 21, 29, 96; Ni: 0, 20, 50; Co: 0, 16, 51; Pb; -, 52, 61. It should be noted that treatment in plants is much more elaborate (oxidation by chlorine dioxide, application of activated silica and a one hour contact time with the sludge bed) than in pilot experiments (15 minutes contact time and a sludge bed without activated carbon).
The oxidation state of metals plays an important role in techniques for their elimination by the usual methods such as coagulation-flocculation-decantation as well as in coprecipitation phenomena of Fe and Mn for example.
The method of alkaline precipitation, in which the pH value needed is obtained by addition of lime, results in elimination rates over 80% and generally far over 90%. This method uses at the same time direct precipitation and coprecipitation in a calcium carbonate/magnesium oxide matrix.
Ion exchange gives highly variable elimination results according to the ion present and its concentration. In practice, strong cation exchange resin are generally applied.
In treatment plants, adsorption on carbon allows an overall yield of 50-100% removal of the metal concerned, provided that preoxidation and sufficient contact times are allowed. The experimental distinction of the specific effect due to adsorption is difficult, but according to our studies, adsorption occurs to a small extent only in the majority of cases.
30-50% of the remaining traces are eliminated by infiltration of purified waters underground, where a levelling of concentrations also occurs.
In addition to the investigations presented, studies still being carried out demonstrate a sufficient stabilization of heavy metals immobilized with lime in order to allow them to be dumped in the environment without risk. This method seems confirmed as a method of choice in treatment of waste waters loaded with heavy metals.