bluuebunny/crossref_metadata_2025 huggingface dataset:
A High Load of Non-neutral Amino-Acid Polymorphisms Explains High Protein Diversity Despite Moderate Effective Population Size in a Marine Bivalve With Sweepstakes Reproduction
Authors: Harrang Estelle , Lapègue Sylvie , Morga Benjamin , Bierne Nicolas
Published: February 2013

Marine bivalves show among the greatest allozyme diversity ever reported in Eukaryotes, putting them historically at the heart of the neutralist−selectionist controversy on the maintenance of genetic variation. Although it is now acknowledged that this high diversity is most probably a simple consequence of a large population size, convincing support for this explanation would require a rigorous assessment of the silent nucleotide diversity in natural populations of marine bivalves, which has not yet been done. This study investigated DNA sequence polymorphism in a set of 37 nuclear loci in wild samples of the flat oyster Ostrea edulis. Silent diversity was found to be only moderate (0.7%), and there was no departure from demographic equilibrium under the Wright-Fisher model, suggesting that the effective population size might not be as large as might have been expected. In accordance with allozyme heterozygosity, nonsynonymous diversity was comparatively very high (0.3%), so that the nonsynonymous to silent diversity ratio reached a value rarely observed in any other organism. We estimated that one-quarter of amino acid-changing mutations behave as neutral in O. edulis, and as many as one-third are sufficiently weakly selected to segregate at low frequency in the polymorphism. Finally, we inferred that one oyster is expected to carry more than 4800 non-neutral alleles (or 4.2 cM−1). We conclude that a high load of segregating non-neutral amino-acid polymorphisms contributes to high protein diversity in O. edulis. The high fecundity of marine bivalves together with an unpredictable and highly variable success of reproduction and recruitment (sweepstakes reproduction) might produce a greater decoupling between Ne and N than in other organisms with lower fecundities, and we suggest this could explain why a higher segregating load could be maintained for a given silent mutation effective size.
Disclosure of Incidental Findings From Next-Generation Sequencing in Pediatric Genomic Research
Authors: Abdul-Karim Ruqayyah , Berkman Benjamin E. , Wendler David , Rid Annette , Khan Javed , Badgett Tom , Hull Sara Chandros
Published: February 2013

Next-generation sequencing technologies will likely be used with increasing frequency in pediatric research. One consequence will be the increased identification of individual genomic research findings that are incidental to the aims of the research. Although researchers and ethicists have raised theoretical concerns about incidental findings in the context of genetic research, next-generation sequencing will make this once largely hypothetical concern an increasing reality. Most commentators have begun to accept the notion that there is some duty to disclose individual genetic research results to research subjects; however, the scope of that duty remains unclear. These issues are especially complicated in the pediatric setting, where subjects cannot currently but typically will eventually be able to make their own medical decisions at the age of adulthood. This article discusses the management of incidental findings in the context of pediatric genomic research. We provide an overview of the current literature and propose a framework to manage incidental findings in this unique context, based on what we believe is a limited responsibility to disclose. We hope this will be a useful source of guidance for investigators, institutional review boards, and bioethicists that anticipates the complicated ethical issues raised by advances in genomic technology.
Suspected Pheochromocytoma in a Patient With Guillain-Barré Syndrome
Authors: Abdel-Salam Fattma , Basu Anna Purna , Johnson Sally , Devlin Anita M.
Published: February 2013

Autonomic instability is well recognized in Guillain-Barré syndrome (GBS), particularly in the acute inflammatory demyelinating polyneuropathy subtype. Hypertension occurs in up to two-thirds of children with GBS but is rarely the main presenting feature. We describe a teenager who presented with tachycardia, dizziness, flushing, and significant hypertension as well as ascending limb weakness and sensory disturbance with areflexia. Because the predominant initial concern was hypertension, she was referred to pediatric nephrology and appropriate investigations for hypertension were conducted. Her neurologic findings prompted a neurology referral, and a diagnosis of GBS was made. The investigations for hypertension subsequently revealed increased urinary normetadrenaline levels in a range consistent with pheochromocytoma, prompting the question of dual pathology. Both autonomic symptoms and urinary metadrenaline levels subsided with GBS resolution, and further investigations excluded the diagnosis of pheochromocytoma. Our case highlights that significant dysautonomia can occur in children with GBS, with hypertension being a prominent early feature. Recognition that urinary metadrenalines can increase to levels seen in pheochromocytoma is important in avoiding diagnostic confusion.
Level of Trainee and Tracheal Intubation Outcomes
Authors: Sanders Ronald C. , Giuliano John S. , Sullivan Janice E. , Brown Calvin A. , Walls Ron M. , Nadkarni Vinay , Nishisaki Akira ,   for the National Emergency Airway Registry for Children Investigators and Pediatric Acute Lung Injury and Sepsis Investigators Network
Published: February 2013

BACKGROUND:

Tracheal intubation is an important intervention to stabilize critically ill and injured children. Provider training level has been associated with procedural safety and outcomes in the neonatal intensive care settings. We hypothesized that tracheal intubation success and adverse tracheal intubation–associated events are correlated with provider training level in the PICU.

METHODS:

A prospective multicenter observational cohort study was performed across 15 PICUs to evaluate tracheal intubation between July 2010 to December 2011. All data were collected by using a standard National Emergency Airway Registry for Children reporting system endorsed as a Quality Improvement project of the Pediatric Acute Lung Injury and Sepsis Investigator network. Outcome measures included first attempt success, overall success, and adverse tracheal intubation–associated events.

RESULTS:

Reported were 1265 primary oral intubation encounters by pediatric providers. First and overall attempt success were residents (37%, 51%), fellows (70%, 89%), and attending physicians (72%, 94%). After adjustment for relevant patient factors, fellow provider was associated with a higher rate of first attempt success (odds ratio [OR], 4.29; 95% confidence interval [CI], 3.24–5.68) and overall success (OR, 9.27; 95% CI, 6.56–13.1) compared with residents. Fellow (versus resident) as first airway provider was associated with fewer tracheal intubation associated events (OR, 0.42; 95% CI, 0.31–0.57).

CONCLUSIONS:

Across a broad spectrum of PICUs, resident provider tracheal intubation success is low and adverse associated events are high, compared with fellows. More intensive pediatric resident procedural training is necessary before “live” tracheal intubations in the intensive care setting.
School Environment and Adolescent Depressive Symptoms: A Multilevel Longitudinal Study
Authors: Brière Frédéric N. , Pascal Sophie , Dupéré Véronique , Janosz Michel
Published: February 2013

OBJECTIVE:

It remains unclear whether school environments can influence the emotional health of adolescents. In this large-scale prospective study, we use multilevel modeling to examine whether the school socioeducational environment contributes to the risk of developing depressive symptoms in secondary school students.

METHODS:

As part of a longitudinal study on school success in disadvantaged communities, 5262 adolescents from 71 secondary schools were followed annually. Socioeducational environment was assessed by a composite measure of social climate, learning opportunities, fairness and clarity of rules, and safety. Depressive symptoms were evaluated by using the Center for Epidemiologic Studies Depression scale. Multilevel regressions tested the association between school socioeducational environment in grade 8 and depressive symptoms in grades 10 to 11, adjusting for previous depressive symptoms in grade 7 and potential confounders at the individual and school levels.

RESULTS:

Modest but significant variation in depressive symptoms was found between schools (intraclass correlation = 3.3%). School-level socioeducational environment in grade 8 was predictive of student depressive symptoms in grades 10 to 11, even after adjusting for potential school and individual confounders. This association was slightly stronger for girls. Student perceptions of school socioeducational environment were also predictive of depressive symptoms. Other school-level factors, including school size, were not predictive of depressive symptoms once socioeducational environment was taken into account.

CONCLUSIONS:

Adolescents who attend a secondary school with a better socioeducational environment are at reduced risk of developing depressive symptoms. School environments appear to have a greater influence on risk in adolescent girls than boys.
Pediatric Advance Care Planning: A Systematic Review
Authors: Lotz Julia D. , Jox Ralf J. , Borasio Gian Domenico , Führer Monika
Published: February 2013

BACKGROUND AND OBJECTIVES:

Advance care planning (ACP) is increasingly regarded as the gold standard in the care of patients with life-limiting illnesses. Research has focused on adults, but ACP is also being practiced in pediatrics. We conducted a systematic review on empirical literature on pediatric ACP (pACP) to assess current practices, effects, and perspectives of pACP.

METHODS:

We searched PubMed, BELIT, and PSYCinfo for empirical literature on pACP, published January 1991 through January 2012. Titles, abstracts, and full texts were screened by 3 independent reviewers for studies that met the predefined criteria. The evidence level of the studies was assessed. Relevant study outcomes were retrieved according to predefined questions.

RESULTS:

We included 5 qualitative and 8 quantitative studies. Only 3 pACP programs were identified, all from the United States. Two of them were informed by adult programs. Major pACP features are discussions between families and care providers, as well as advance directives. A chaplain and other providers may be involved if required. Programs vary in how well they are evaluated; only 1 was studied by using a randomized controlled trial. Preliminary data suggest that pACP can successfully be implemented and is perceived as helpful. It may be emotionally relieving and facilitate communication and decision-making. Major challenges are negative reactions from emergency services, schools, and the community.

CONCLUSIONS:

There are few systematic pACP programs worldwide and none in Europe. Future research should investigate the needs of all stakeholders. In particular, the perspective of professionals has so far been neglected.
Spontaneous Bisphosphonate‐Induced Osteonecrosis of a Mid‐Palatal Torus: A Case Report
Authors: McLeod Dwight E. , Gautam Medha , Reyes Elio , Pandarakalam Cyril , Seyer Bradley A.
Published: February 2013

Introduction: Bisphosphonates (BPs) are commonly used in the United States primarily in postmenopausal females with a history of osteoporosis. BP therapy may result in bisphosphonate‐related osteonecrosis of the jaw (BRONJ). BRONJ is described as exposed bone in the maxillofacial region persisting for >8 weeks in a patient who is taking or has taken a BP and has not had radiation therapy to the head and neck. The prevalence of BRONJ seems to vary depending on the mode and frequency of administration, drug potency, duration of treatment, and other factors.

Case Presentation: This case report describes an incidence of BP‐induced osteonecrosis of a mid‐palatal torus in a 77‐year‐old patient of African‐European heritage who was previously treated for osteoporosis. The lesion appeared as a pustulated erythematous soft‐tissue mass with partially exposed bone covered in plaque. The lesion was surgically debrided using a modified flap procedure and sent for histopathologic analysis. Systemic antibiotics, pain medication, and antimicrobial mouthrinse were prescribed. The mid‐palatal area healed without complications, and the histopathology was consistent with BP‐induced osteonecrosis with evidence of Actinomyces species.

Conclusions: With the widespread use of BPs and the prevalence of tori and/or exostoses, it is likely that clinicians may encounter a greater frequency of BP‐induced osteonecrosis of these poorly vascularized bony growths that may initiate from daily traumatic oral activities. Clinicians should communicate to their patients the potential dangers that necrosis may cause. Treatment should be decisive, urgent, and incorporate aggressive management.
Health risks associated with drinking water in a context of climate change in France: a review of surveillance requirements
Authors: Beaudeau Pascal , Pascal Mathilde , Mouly Damien , Galey Catherine , Thomas Olivier
Published: February 2013

It is widely recognized that climate change will impact upon human health in a variety of ways. Assessing these impacts and identifying adaptation opportunities requires appropriate monitoring. To identify the need for reinforced surveillance in metropolitan France, we defined a conceptual framework of how climate change could impact upon health risks in relation to drinking water. Three types of climate change-related impacts were identified: changes in raw water quality, changes in water treatment processes and changes in human determinants of exposure in relation to consumers' behaviour. This framework was applied to existing risks and exposure situations in France. An increase in the health burden attributable to drinking water intake is expected due to increased exposure to faecal pathogens, disinfection by-products and cyanobacteria as a result of a combination of natural, technical and human factors. Current sources of health and water data should satisfy surveillance requirements. However, we believe that the creation of a sustainable database comprising behavioural and water management data would be valuable in following and understanding emerging trends.
New planning technique to master the future of water on local and regional level in Ukraine
Authors: Zhovtonog Olga , Hoffmann Michael , Polishchuk Vitali , Dubel Anna
Published: February 2013

A new water resource planning technique was developed for regional and local levels of water management in Ukraine. For this purpose, methodology, methods and tools, as implemented in the Water Scenarios for Europe and for Neighbouring States (SCENES) project, were studied and adapted to the specific situation of the Crimea pilot area in the South Region of Ukraine. For testing of the new planning techniques, a participatory scenario development process was organised and implemented with Crimean stakeholders. Various facilitation tools and supporting measures were incorporated into the methodology for general scenario development. Causal Loop Diagrams on the problems of irrigation performance in Crimea and enrichment (down and cross scaling) with results from other pilots were also used. These tools increased stakeholders' insights and quality of outcomes and stimulated social learning. The scenario development process ends up in the formulation of storylines, action plans and policy recommendations.
Long-term dynamics of water-borne nitrogen, phosphorus and suspended solids in the lower Don River basin (Russian Federation)
Authors: Zhulidov A. V. , Kämäri J. , Robarts R. D. , Pavlov D. F. , Rekolainen S. , Gurtovaya T. Yu. , Meriläinen J. J. , Lugovoy V. V.
Published: February 2013

A long-term study (1986–2002) of water-borne nutrient and suspended solids dynamics was undertaken on the lower Don River, which plays an extremely important role in the water supply of the Black Sea and Azov Sea basin. Suspended solids were greatest in spring and summer and were correlated to river discharge. Mean annual nitrogen concentrations increased from 1986 to 1995 and then decreased from 1996 to 2002. Unlike nitrogen, phosphorus concentrations (both phosphates and total phosphorus) gradually increased throughout the study period changing the river from an oligotrophic to upper mesotrophic status. If this trend continues phytoplankton could become nitrogen-limited leading to the development of nitrogen-fixing cyanobacterial blooms. No obvious relation between fertiliser usage over the Rostovskaya Oblast and nutrient dynamic patterns was identified, probably because only 10% of the water in the river comes from this area. The reason for the unusual and contradictory nitrogen and phosphorus changes remain largely unknown for this regulated river.
Using a participatory scenario development toolbox: added values and impact on quality of scenarios
Authors: Kok Kasper , van Vliet Mathijs
Published: February 2013

To capture a system's uncertainty, a participatory, integrated approach is a prerequisite of many scenario development projects. Increasingly, a toolbox of methods is employed to facilitate stakeholder input. In this paper we evaluate four potential added values of using a toolbox of methods and the effect on the quality of resulting scenarios. Ten case studies within a large project (SCENES), that set out to develop participatory scenarios for Europe's freshwaters, are used to test our hypotheses. We analysed a first series of scenario workshops, evaluating (dis)advantages of the toolbox and the quality of scenarios as perceived by stakeholders and local organisers. As can be deduced from the resulting scenarios, results indicate that all hypothesised added values materialised to some extent. Using a toolbox enlarges the possibilities to: (1) adapt to local circumstances; (2) adapt to a variety of stakeholders; (3) compare results across scales and across case studies; and (4) facilitate a link of models and stories. However, a careful balance has to be found between the length of workshop, number and type of tools employed, and previous experience of stakeholders and local organisers. The results have implications for practitioners setting out to develop water or climate adaptation scenarios that could benefit from all the added values tested here. Finally, employing a toolbox can positively influence scenario quality, although more structured tests are needed.
Incorporation of the Multiple Barrier Approach in drinking water risk assessment tools
Authors: Summerscales Ian Michael , McBean Edward A.
Published: February 2013

A number of existing risk assessment tools make reference to, or incorporate, a Multiple Barrier Approach to drinking water safety. Three waterborne disease outbreaks that occurred in developed nations were used as case studies to test a selected set of risk assessment tools. The outbreaks were used to determine how well the risk assessment tools identify hazards and vulnerabilities associated with different barriers to drinking water contamination.
Virus removal efficiency of Cambodian ceramic pot water purifiers
Authors: Salsali Hamidreza , McBean Edward , Brunsting Joseph
Published: February 2013

Virus removal efficiency is described for three types of silver-impregnated, ceramic water filters (CWFs) produced in Cambodia. The tests were completed using freshly scrubbed filters and de-ionized (DI) water as an evaluation of the removal efficiency of the virus in isolation with no other interacting water quality variables. Removal efficiencies between 0.21 and 0.45 log are evidenced, which is significantly lower than results obtained in testing of similar filters by other investigators utilizing surface or rain water and a less frequent cleaning regime. Other experiments generally found virus removal efficiencies greater than 1.0 log. This difference may be because of the association of viruses with suspended solids, and subsequent removal of these solids during filtration. Variability in virus removal efficiencies between pots of the same manufacturer, and observed flow rates outside the manufacturer's specifications, suggest tighter quality control and consistency may be needed during production.
Detection of assemblages A and B of Giardia duodenalis in water and sewage from São Paulo state, Brazil
Authors: Fernandes Licia Natal , de Souza Patrícia Pereira , de Araújo Ronalda Silva , Razzolini Maria Tereza Pepe , Soares Rodrigo Martins , Sato Maria Inês Zanoli , Hachich Elayse Maria , Cutolo Silvana Audrá , Matté Glavur Rogério , Matté Maria Helena
Published: February 2013

Giardia duodenalis is a protozoan that parasitizes humans and other mammals and causes giardiasis. Although its isolates have been divided into seven assemblages, named A to G, only A and B have been detected in human faeces. Assemblage A isolates are commonly divided into two genotypes, AI and AII. Even though information about the presence of this protozoan in water and sewage is available in Brazil, it is important to verify the distribution of different assemblages that might be present, which can only be done by genotyping techniques. A total of 24 raw and treated sewage, surface and spring water samples were collected, concentrated and purified. DNA was extracted, and a nested PCR was used to amplify an 890 bp fragment of the gdh gene of G. duodenalis, which codes for glutamate dehydrogenase. Positive samples were cloned and sequenced. Ten out of 24 (41.6%) samples were confirmed to be positive for G. duodenalis by sequencing. Phylogenetic analysis grouped most sequences with G. duodenalis genotype AII from GenBank. Only two raw sewage samples presented sequences assigned to assemblage B. In one of these samples genotype AII was also detected. As these assemblages/genotypes are commonly associated to human giardiasis, the contact with these matrices represents risk for public health.
Electrochemical dechlorination of 2,4-dichlorophenol in aqueous solution on palladium-loaded meshed titanium electrode
Authors: Sun Z. R. , Gao M. , Peng Y. Z. , Hu X.
Published: February 2013

Electrochemical dechlorination of 2,4-dichlorophenol (2,4-DCP) in aqueous solution was investigated on palladium-loaded meshed titanium (Pd/Ti) electrode at ambient temperature. Pd/Ti electrode was prepared with an electrodepositing method. Scanning Electron Microscope (SEM) micrographs show that Pd microparticles uniformly disperse on the meshed Ti supporting electrode with spheroidal structure. Dechlorination experimental results indicate that, in aqueous solution, with the current efficiency of 24.3%, the removal efficiency of 100 mg/L 2,4-DCP on Pd/Ti electrode was 93.2% under the conditions of the dechlorination current of 5 mA and dechlorination time of 90 min. The effect of initial 2,4-DCP concentration was also investigated.
Issues of drinking water quality of small scale water services towards climate change
Authors: Delpla I. , Baures E. , Jung A. V. , Clement M. , Thomas O.
Published: February 2013

As climate change could impact water quantity and quality, important concerns are related to water quality degradation in small scale water services (SSWS). SSWS using surface waters resources (rivers and lakes) for drinking water production are particularly vulnerable to short term transient events due to their low adaptation capacity and their lack of support and technical knowledge compared to major centralized systems. Based on weather and water quality databases, a case study was conducted on a SSWS in Brittany (France) pumping from surface water. Results show an important vulnerability in treatment efficiency related to the lowest and highest river flows and provide first assumptions about the impacts of an increase in extreme weather events with climate change on drinking water quality.
Evaluation of effectiveness of combined sewer overflow control measures by operational data
Authors: Schroeder K. , Riechel M. , Matzinger A. , Rouault P. , Sonnenberg H. , Pawlowsky-Reusing E. , Gnirss R.
Published: February 2013

The effect of combined sewer overflow (CSO) control measures should be validated during operation based on monitoring of CSO activity and subsequent comparison with (legal) requirements. However, most CSO monitoring programs have been started only recently and therefore no long-term data is available for reliable efficiency control. A method is proposed that focuses on rainfall data for evaluating the effectiveness of CSO control measures. It is applicable if a sufficient time-series of rainfall data and a limited set of data on CSO discharges are available. The method is demonstrated for four catchments of the Berlin combined sewer system. The analysis of the 2000–2007 data shows the effect of CSO control measures, such as activation of in-pipe storage capacities within the Berlin system. The catchment, where measures are fully implemented shows less than 40% of the CSO activity of those catchments, where measures have not yet or not yet completely been realised.
Reducing CSOs and giving the river back to the public: innovative combined sewer overflow control and riverbanks restoration of the St Charles River in Quebec City
Authors: Fradet Olivier , Pleau Martin , Marcoux Christiane
Published: February 2013

After the construction of its wastewater treatment plants, the City of Quebec began to implement overflow control in wet weather to ultimately meet the effluent discharge objectives, i.e. no more than two overflows per summer season in the St. Lawrence River and no more than four in the St-Charles River. After several years of studies to determine which management strategies would best suit the purpose, and to propose optimum solutions, a first project to implement optimal and predictive management in real time, called « Pilot », came to life in 1999. Construction in phases soon followed and the work was completed in the fall of 2009. As a result, requirements with regard to environmental rejects were met in two sectors, namely the St-Charles River and the Jacques-Cartier Beach, and aquatic recreational activities could resume. Meanwhile, the City also worked at giving back access to the water courses to the public by developing sites at the Jacques-Cartier Beach and in the Bay of Beauport, and by rehabilitating the banks of the St-Charles River.
Long-term operation of a reactor enriched in Accumulibacter clade I DPAOs: performance with nitrate, nitrite and oxygen
Authors: Lanham A. B. , Moita R. , Lemos P. C. , Reis M. A. M.
Published: February 2013

The microbiology of denitrifying enhanced biological phosphorus removal systems has been a subject of much debate. The question has centred on the affinities of different types of Candidatus Accumulibacter PAOs, type I and type II, towards different electron acceptors such as oxygen, nitrate and nitrite. This study used a propionate anaerobic/anoxic/aerobic lab-scale sequencing batch reactor where a microbial culture was successfully enriched in Accumulibacter type I organisms (approx. 90%). The culture was able to take up phosphorus using nitrate, nitrite and oxygen as electron acceptors, although experiments with oxygen led to the fastest P removal rate. The phosphorus uptake to nitrogen consumed ratio (P/N ratio), when using both nitrate and nitrite, was shown to be affected by pH in the range of 7–8.2, achieving higher values for lower pH values (7.0–7.5). The effect of pH on P removal seems to follow a similar trend for both nitrate and nitrite. To our knowledge, this is the first study where the impact of pH in the phosphate removal stoichiometry using the three most significant electron acceptors is shown for such a high enrichment in Accumulibacter type I.
Characterization of microbial community structures and their activities in single anaerobic granules by beta imaging, microsensors and fluorescence in situ hybridization
Authors: Satoh H. , Tsushima I. , Miura Y. , Ito T. , Okabe S.
Published: February 2013

The spatial distribution of microorganisms and their in situ activities in anaerobic granules were investigated by fluorescence in situ hybridization (FISH), beta imaging and microsensors. FISH results revealed a layered structure of microorganisms in the granule, where Chloroflexi was present in the outermost layer, Smithella spp. and Syntrophobacter spp. were found in a depth of ca. 100 μm, and Archaea was restricted to the inner layer (below ca. 300 μm from the surface). Substrate uptake patterns elucidated by beta imaging demonstrated that glucose uptake was highest at 50 μm depth, whereas propionate uptake had a peak at 200 μm depth. In addition, microsensor measurements revealed that acid was produced mainly at 100 μm depth and H2 production was detected at a depth from 100 to 200 μm. H2 consumption and corresponding CH4 production were found below 200 μm from the surface. Direct comparison of these results implied sequential degradation of complex organic compounds in anaerobic granules; Chloroflexi contributed to fermentation of organic compounds and acid production in the outermost layer, volatile fatty acids were oxidized and H2 was produced mainly by Smithella spp. and Syntrophobacter spp. at a depth from 100 to 200 μm, and Archaea produced CH4 below ca. 300 μm from the surface.
Biodegradation of o-nitrophenol by aerobic granules with glucose as co-substrate
Authors: Basheer Farrukh , Isa M. H. , Farooqi I. H.
Published: February 2013

Aerobic granules to treat wastewater containing o-nitrophenol were successfully developed in a sequencing batch reactor (SBR) using activated sludge as inoculum. Stable aerobic granules were obtained with a clearly defined shape and diameters ranging from 2 to 6 mm after 122 days of operation. The integrity coefficient (IC) and granules density was found to be 98% and 1,054 kg m−3 respectively. After development of aerobic granules, o-nitrophenols were successfully degraded to an efficiency of 78% at a concentration of 70 mg L−1. GC-MS study revealed that the biodegradation of o-nitrophenol occured via catechol via nitrobenzene pathway. Specific o-nitrophenol biodegradation rates followed the Haldane model and the associated kinetic parameters were found as follows: Vmax = 3.96 g o-nitrophenol g−1VSS−1d−1, Ks = 198.12 mg L−1, and Ki = 31.16 mg L−1. The aerobic granules proved to be a feasible and effective way to degrade o-nitrophenol containing wastewater.
Direct precipitation on demand at large Scandinavian WWTPs reduces the effluent phosphorus load
Authors: Mattsson Ann , Nivert Glen , Heinonen Mari
Published: February 2013

On demand use of direct precipitation of wastewater has been successfully implemented at several large Scandinavian wastewater treatment plants (WWTPs) as a cost-efficient method of treating wastewater bypassing secondary treatment. During wet weather situations or when the capacity of secondary treatment is reduced excess wastewater can be treated through efficient direct precipitation. This increases the total capacity of the WWTP to remove phosphorus during these periods. This treatment strategy allows the WWTPs to meet stringent effluent phosphorus limits without extending secondary treatment of the main plant, despite high wet weather flows. The gain in terms of reduced phosphorus emissions varies depending on local conditions such as climate, collection system and secondary treatment capacity. It also varies from year to year depending on the weather and reductions of capacity due to planned refurbishing or unplanned breakdown of equipment. Operating chemical precipitation on demand has proved to contain challenges to operation and organisation of the WWTP. These challenges include logistics of start-up, training of staff and maintaining the system between occasions of operation. Sufficient up-stream storage capacity, reliable weather forecasts and good contracts with suppliers of chemicals are keys of success.
Frequency analysis of river water quality using integrated urban wastewater models
Authors: Fu Guangtao , Butler David
Published: February 2013

In recent years integrated models have been developed to simulate the entire urban wastewater system, including urban drainage systems, wastewater treatment plants, and receiving waterbodies. This paper uses such an integrated urban wastewater model to analyze the frequency of receiving water quality in an urban wastewater system with the aim of assessing the overall system performance during rainfall events. The receiving water quality is represented by two indicators: event mean dissolved oxygen (DO) concentration and event mean ammonium concentration. The compliance probability of the water quality indicators satisfying a specific threshold is used to represent the system performance, and is derived using the rainfall events from a series of 10 years' rainfall data. A strong correlation between the depth of each rainfall event and the associated volume of combined sewer overflow (CSO) discharges is revealed for the case study catchment, while there is a low correlation between the intensity/duration of the rainfall event and the volume of the CSO discharges. The frequency analysis results obtained suggest that the event mean DO and ammonium concentrations have very different characteristics in terms of compliance probabilities at two discharging points for CSO and wastewater treatment plant effluent, respectively. In general, the simulation results provide an understanding of the performance of the integrated urban wastewater system and can provide useful information to support water quality management.
The distribution, accumulation and potential source of seldom monitored trace elements in sediments of Beijiang River, South China
Authors: Gao Bo , Lu Jin , Zhou Huai-Dong , Yin Shu-Hua , Hao Hong
Published: February 2013

A geochemical study of Beijiang River sediments was carried out to analyze the concentrations, distribution, accumulation and potential sources of the seldom monitored trace elements (SMTEs: Sc, V, Co, Ga, Y, Sn and Sb). The mean concentrations of Sc, V, Co, Ga, Y, Sn and Sb were 8.2, 60.3, 9.6, 17.2, 28.6, 85.6 and 39.0 mg/kg, respectively. The concentrations of the SMTEs, together with their spatial distribution showed that the SMTEs were mainly due to anthropogenic inputs from the metal smelting industries and local mining activities in the upper region of the river. The assessment by geoaccumulation index indicates that Sc, V, Co, Ga and Y are at the unpolluted level, Sn is at the ‘strongly contaminated’ level, and Sb is at the ‘extremely contaminated’ level. The pollution level of the SMTEs is: Sb > Sn > Y > Ga > Co > V > Sc. The results of correlation analysis and principal component analysis indicated the Sn and Sb were positively correlated with each other, indicating a common source in sediments. In conclusion, our results indicate that the sediments in Beijiang River have been severely contaminated by Sn and Sb.
SSUIS – a research model for predicting suspended solids loads in stormwater runoff from urban impervious surfaces
Authors: Brodie Ian M.
Published: February 2013

Suspended solids from urban impervious surfaces (SSUIS) is a spreadsheet-based model that predicts the mass loading of suspended solids (SS) in stormwater runoff generated from impervious urban surfaces. The model is intended to be a research tool and incorporates several particle accumulation and washoff processes. Development of SSUIS is based on interpretation of storm event data obtained from a galvanised iron roof, a concrete car park and a bitumen road located in Toowoomba, Australia. SSUIS is a source area model that tracks the particle mass balance on the impervious surface and within its lateral drain to a point of discharge. Particles are separated into two groups: free and detained, depending on the rainfall energy required for surface washoff. Calibration and verification of SSUIS against the Toowoomba SS data yielded R2 values ranging from 0.60 to 0.98. Parameter sensitivity analysis and an example of how SSUIS can be applied to predict the treatment efficiency of a grass swale are also provided.
Effect of integrating straw into agricultural soils on soil infiltration and evaporation
Authors: Cao Jiansheng , Liu Changming , Zhang Wanjun , Guo Yunlong
Published: February 2013

Soil water movement is a critical consideration for crop yield in straw-integrated fields. This study used an indoor soil column experiment to determine soil infiltration and evaporation characteristics in three forms of direct straw-integrated soils (straw mulching, straw mixing and straw inter-layering). Straw mulching is covering the land surface with straw. Straw mixing is mixing straw with the top 10 cm surface soil. Then straw inter-layering is placing straw at the 20 cm soil depth. There are generally good correlations among the mulch integration methods at p < 0.05, and with average errors/biases <10%. Straw mixing exhibited the best effect in terms of soil infiltration, followed by straw mulching. Due to over-burden weight-compaction effect, straw inter-layering somehow retarded soil infiltration. In terms of soil water evaporation, straw mulching exhibited the best effect. This was followed by straw mixing and then straw inter-layering. Straw inter-layering could have a long-lasting positive effect on soil evaporation as it limited the evaporative consumption of deep soil water. The responses of the direct straw integration modes to soil infiltration and evaporation could lay the basis for developing efficient water-conservation strategies. This is especially useful for water-scarce agricultural regions such as the arid/semi-arid regions of China.
Recovery of calcium carbonate from steelmaking slag and utilization for acid mine drainage pre-treatment
Authors: Mulopo J. , Mashego M. , Zvimba J. N.
Published: February 2013

The conversion of steelmaking slag (a waste product of the steelmaking process) to calcium carbonate (CaCO3) was tested using hydrochloric acid, ammonium hydroxide and carbon dioxide via a pH-swing process. Batch reactors were used to assess the technical feasibility of calcium carbonate recovery and its use for pre-treatment of acid mine drainage (AMD) from coal mines. The effects of key process parameters, such as the amount of acid (HCl/calcium molar ratio), the pH and the CO2 flow rate were considered. It was observed that calcium extraction from steelmaking slag significantly increased with an increase in the amount of hydrochloric acid. The CO2 flow rate also had a positive effect on the carbonation reaction rate but did not affect the morphology of the calcium carbonate produced for values less than 2 L/min. The CaCO3 recovered from the bench scale batch reactor demonstrated effective neutralization ability during AMD pre-treatment compared with the commercial laboratory grade CaCO3.
Synergetic degradation of Fe/Cu/C for groundwater polluted by trichloroethylene
Authors: Zhang Wei , Li Li , Lin Kuangfei , Xiong Bang , Li Bingzhi , Lu Shuguang , Guo Meijin , Cui Xinhong
Published: February 2013

This study investigated the enhancement of synergetic degradation of Fe/Cu/C (Fe: commercial iron, Cu: solid product of Fe reacted with CuSO4, C: carbon powder) for simulated groundwater contaminated by trichloroethylene (TCE). Zero valent iron (ZVI) as a reducing agent was proved to be effective for TCE removal. The Fe/Cu/C system resulted in higher reduction efficiency as a result of the synergetic role of Fe/Cu and Fe/C microelectrode than the Fe (ZVI) or Fe/Cu system, and the half-life was only about 0.4 h. When m(Fe) achieved 12.5 g L–1, the residual concentration of TCE almost leveled off. Fe:Cu = 10:1 or m(C) = 0.0086 g can induce the optimum function for TCE degradation. A neutral condition was appropriate for TCE degradation, and an acidic system slightly favored TCE dechlorination compared with an alkaline system. GC/MS analysis indicated that TCE was dechlorinated to 1,1-dichloroethene (1,1-DCE), cis-1,2-dichloroethene (cis-DCE) and vinyl chloride (VC), and 1,1-DCE might be the precursor. Fe/Cu/C reduction is a highly promising technique for TCE removal, and it is an excellent alternative to enhance TCE reductive dechlorination.
Water quality as an indicator of hydrogeological conditions: a case study of the Belgrade Groundwater Source (Sava/Danube confluence area)
Authors: Papić P. , Pušić M. , Todorović M.
Published: February 2013

The City of Belgrade receives most of its drinking water supply from the alluvial aquifer of the Sava River. The wells are radial, placed in the lower part of the aquifer, so they partly run below the Sava riverbed. However, the groundwater quality of the wells in one part of the source (near the confluence of the Sava and Danube rivers) is found to differ somewhat from the groundwater quality of the other wells. The finding gave rise to additional investigations. The results revealed the existence of a deeper, limestone aquifer which is isolated from upper alluvial sediments by a thick layer of clay in most of the terrain. The naturally potential hydraulic contact of the two aquifers was additionally maintained by well operation in this part of the source. According to multiple analyses of groundwater flow using a hydrodynamic mathematical model, a hydrogeological and hydraulic system of groundwater flow was defined. Although the wells are situated adjacent to the river, and some well laterals are below the riverbed, most of the groundwater that flows to the wells is partly from the wider zone of the alluvial aquifer, and partly from the deeper aquifer. The initial results of hydrochemical investigations also showed an unexpected, inverse oxic character of the groundwater in these two aquifers.
Hierarchical MnO2 nanostructures: synthesis and their application in water treatment
Authors: Zhai Rui , Wan Yazhen , Liu Lin , Zhang Xiang , Wang Weiqiang , Liu Jindun , Zhang Bing
Published: February 2013

Hierarchical MnO2 nanostructures were prepared through the reaction between KMnO4 and oleic acid at room temperature in the surfactant-free microemulsion system. The obtained samples were characterized by powder X-ray diffraction, N2 adsorption, scanning electron microscopy, and transmission electron microscopy. The results indicated that the flowerlike nanospheres were three-dimensional (3D) porous microstructures consisting of nanoplates. The surface area of the sample was 171.5 m2/g and the distribution of pore diameter lay within the range of 5–15 nm. The prepared hierarchically structured MnO2 showed excellent adsorption capacity and rapid adsorption rate for methylene blue ions in water. The maximum adsorption capacity of methylene blue was as high as 273.9 mg/g and 97.5% of the dye was removed within initial 5 min of contact time. Compared with other adsorbents, the synthesized hierarchical MnO2 nanostructures displayed a faster adsorption rate and higher adsorption capacity, which implied potential application for removing dye pollutants from waste water.
Visible light assisted photocatalytic degradation of methyl orange using Ag/N–TiO2 photocatalysts
Authors: Wu Deyong , Long Mingce
Published: February 2013

For the sake of efficient utilization of sunlight, Ag nanoparticles loaded N-doped TiO2 photocatalysts (Ag/N–TiO2) were successfully fabricated via a two-step method to make the best use of the respective advantages of noble metal loading and nonmetal doping. Ag/N–TiO2 was characterized using XRD, XPS and UV–Vis DRS. Compared to TiO2, the dramatic enhancement of the visible-light-induced photocatalytic degradation efﬁciency of Ag/N–TiO2 obtained for the degradation of methyl orange should be attributed to the synergistic effect of N-doping and Ag-loading, including the good visible light absorption and the effective electron–hole separations. This demonstrates Ag/N–TiO2 is a promising photocatalytic material for organic pollutant degradation under visible light irradiation.
Preparation, characterization and performance of a novel PVDF/PMMA/TPU blend hollow fiber membrane for wastewater treatment
Authors: Ma C. Y. , Huang J. P. , Xi D. L.
Published: February 2013

Polyvinylidene fluoride (PVDF)/polymethylmethacrylate (PMMA)/thermoplastic polyurethane (TPU) blend hollow fiber membranes were successfully prepared by the wet-spinning method with the loading of PMMA and TPU in a range of polymer concentrations varying from 0 to 20 wt% and at a total polymer concentration of 16 wt%. The influence of the addition of PMMA and TPU on the morphologies and the properties of such prepared membranes was investigated through FTIR-ATR, SEM, viscosity measurements, UF experiments and mechanical strength tests. Based on the experimental results, the compatibility of the PVDF, PMMA and TPU blend was best under the conditions of the PVDF-rich phase. The elongation at break of the membrane increased to a maximum of 146% with increase in the TPU concentration to 20 wt% in dope solution. The addition of PMMA increased the water permeation flux from 120 to 195 L/(m2 h) initially. The flux then decreased when PMMA concentration was increased to over 10 wt%. The membranes obtained at optimized blending ratio were applied to the dyeing process wastewater filtration. During continuous filtration for 8 h, the flux was stabilized at about 20 L/(m2 h) at 0.1 MPa. The reduction in CODCr, turbidity and color were about 63, 84 and 63% respectively.
Biodegradation of 4-methylaniline in a sequencing batch reactor
Authors: Moreno-Andrade Iván , Buitrón Germán
Published: February 2013

The biodegradation of the aromatic amine 4-methylaniline (4MA) using an aerobic sequencing batch reactor was evaluated. The specific degradation rate showed an exponential increase during the acclimation of the microorganisms reaching a maximal value of 34 mg 4MA/VSS/h. After the acclimation, the process showed a stable operation. A high similarity index was observed, indicating a low variation in the population diversity. During this period, the physicochemical parameters demonstrated a stable operation of the reactor.
Methane potential and biodegradability of rice straw, rice husk and rice residues from the drying process
Authors: Contreras L. M. , Schelle H. , Sebrango C. R. , Pereda I.
Published: February 2013

Agricultural solid residues are a potential renewable energy source. Rice harvesting and production in Sancti Spíritus province, Cuba, currently generates residues without an environmentally sustainable disposal route. Rice residues (rice straw, rice husk and rice residues from the drying process) are potentially an important carbon source for anaerobic digestion. For this paper, rice residues were placed for 36 days retention time in anaerobic batch reactor environments at both mesophilic (37 °C) and thermophilic (55 °C) conditions. Biogas and methane yield were determined as well as biogas composition. The results showed that rice straw as well as rice residues from the drying process had the highest biogas and methane yield. Temperature played an important role in determining both biogas yield and kinetics. In all cases, rice straw produced the highest yields; under mesophilic conditions the biogas yield was 0.43 m3 kgVS−1, under thermophilic conditions biogas yield reached 0.52 m3 kgVS−1. In the case of the rice husk, the biodegradability was very low. Methane content in all batches was kept above 55% vol. All digested material had a high carbon:nitrogen (C:N) ratio, even though significant biodegradation was recorded with the exception of rice husk. A first-order model can be used to describe the rice crop residues fermentation effectively.