bluuebunny/crossref_metadata_2025 huggingface dataset:
The power of the “sanctioned discourse” - a crucial factor in determining water policy
Authors: Jägerskog A.
Published: May 2018

The water relations in the Jordan River Basin are an often-analysed case of decision-making under terms of water scarcity. However, most of these studies fail to address the underlying structures, which are the focal point in the formation of each of the basin parties' water policy. This paper argues that it is necessary to analyse the domestic structures of the parties since the policies pursued in the international arena are likely to be a reflection of the domestic discourse. Particular emphasis is put on how domestic structures affect and create sanctioned discourses and how these in turn affect foreign policy decision-making with regards to water. The various dominant discourses in three of the parties in the Jordan River Basin - Jordan, Israel and the Palestine Authority - are analysed. Failing to acknowledge the explanatory power of this line of thinking runs the risk of reaching simplified conclusions, such as - “the policy-makers do not understand water issues” - instead of acknowledging that the power of the discourse perhaps gave them little choice. The paper draws on a variety of disciplines such as international relations theory, sociology and science studies.
Performance of constructed wetland systems treating anerobic effluents
Authors: de Sousa J.T. , van Haandel A. , Lima E.P.C. , Guimaraes A.V.A.
Published: May 2018

The purpose of this present paper is to verify the performance of three wetland systems operated with effluents from a UASB reactor, with respect nutrient removal (nitrogen and phosphorus), pathogenic organisms and remaining carbonaceous material, monitored over a three-year period. The experiment was carried out and monitored at PROSAB (Programa de Saneamento Básico) in Campina Grande, Para'ba. The removal efficiency of the carbonaceous material expressed in DQO ranged from 70 to 86%, but concerning the total suspended solids, the efficiency ranged from 50 to 71%. The removal efficiency in terms of nitrogen and phosphorus of both vegetated systems was about 65.5 to 86%, respectively, during the first year of operation. Under the operational conditions of the experiment, the removal of phosphorus in a wetland system containing washed sand as the substratum decreased, as its operation period increased. The vegetated wetland has been the most efficient in removing faecal coliforms (roughly 4 log units) as compared to the non-vegetated one (about 3 log units), when both were operated with the same hydraulic load (2.3 cm. per day). Thus, the effluent produced over the three-year period ranged from 800 to 1,800 UFC/100 mL in the analyzed samples.
Downstream morphological change in response to dam construction: a GIS based approach for the Lower Ord River, Western Australia
Authors: Cluett L.J. , Radford B.T.M.
Published: May 2018

Flow regulation in the Lower Ord River began in 1963 with the completion of the Kununurra Diversion Dam, part of a large-scale irrigation scheme in the far north of Western Australia. What was previously an ephemeral river punctuated by large flood events now contains permanent, regulated flows all year round, and fundamental changes in the downstream channel morphology are now evident. Further changes to the regulated flow regime are planned as part of the eventual expansion of the irrigation area. It is necessary to understand and document the channel responses that have occurred in the Lower Ord so far as a result of flow regulation. This paper presents a GIS based investigation into morphological change in the Lower Ord River. Geomorphic surface data are largely generated from sequential aerial photographs, calibrated using field observations and historical records. Results illustrate the changes in the total area of each surface type, the direction of change in bar evolution and the significance of changes in channel width throughout the study reach.
The potential contribution of the Queensland Wet Tropics Region Natural Resource Plan to river improvement and water quality
Authors: McDonald G. , Weston N. , Dorrington B.
Published: May 2018

This paper reports on work in progress on the new Wet Tropics Regional Natural Resource Management Plan and its potential to deliver river management and water quality outcomes. The plan is being prepared in accordance with the guidelines of the Nation Action Plan for Salinity and Water Quality/Natural Heritage Trust (NAP/NHT2). In particular the paper discusses the technical basis for priorities, target setting and implementation and the most effective instruments for achieving river improvement and water quality outcomes in the region.
Linking atmospheric circulation to daily rainfall patterns across the Murrumbidgee River Basin
Authors: Charles S.P. , Bates B.C. , Viney N.R.
Published: May 2018

The hydrological cycle in Australia covers an extraordinary range of climatic and hydrologic regimes. It is now widely accepted that Australian hydrology is significantly different from all other regions and continents with the partial exception of southern Africa. Rainfall variability is very high in almost all regions with respect to amount and the lengths of wet and dry spells. These factors are keys to the behaviour and health of Australian aquatic ecosystems and water resources. Thus assessment of how rainfall may change under a potential future climate is critical. For a case study of the Murrumbidgee River Basin (MRB), a statistical downscaling model that links broad scale atmospheric circulation to multi-site, daily precipitation is assessed using observed data. This model can be driven with climate model simulations to produce rainfall scenarios at the scale required by impacts models. These can then be used in probabilistic risk assessments of climate change impacts on river health. These issues will be discussed in the context of assessing the potential impacts of precipitation changes due to projected climate change on river health.
Advanced nitrogen elimination by encapsulated nitrifiers
Authors: Sievers M. , Vorlop K.-D. , Hahne J. , Schlieker M. , Schäfer S.
Published: May 2018

By introducing a mixed population of nitrifiers encapsulated in gel lens beads a more selective nitrification process was found in treatment of settled sewage in lab scale at a hydraulic retention time (HRT) of about 30 to 60 minutes. The reaction rates for oxidation of soluble chemical oxygen demand (SCOD) were found to vary between 25 to 150 mg/L·h while nitrification takes place around 50 mg nitrogen per hour and litre reaction volume. However, based on this SCOD removal in the nitrification step, a consequent post-denitrification process without nitrate recycle and dosage of external carbon sources has been proven to reach substantial nitrate elimination of up to 20 mg nitrogen per litre at COD/N-ratios of approx. 6 in settled sewage. At such COD/N-ratios, suitable nitrogen elimination seems to be possible, because the bioflocs of settled sewage, produced so far by SCOD oxidation and entrapment of particulate COD, are passing through the nitrification process having a substantial contribution to the denitrification rate additionally to the remaining SCOD.
Characterisation of aerobic bio treatment of meat plant effluent
Authors: Thayalakumaran N. , Bhamidimarri R. , Bickers P.O.
Published: May 2018

Primary treated meat processing plant effluent was characterised for the calibration of the ASM 2 model. The total COD of the wastewater was 500-2,000 mg L-1. The wastewater contained 15-18% of RBCOD. RBCOD of the meat processing wastewater was from short chain fatty acids (SCFA). Acetic and iso-valeric acids contributed 50% of the total SCFA COD. The inert soluble and particulate COD fractions were each 4%. The COD exerted by carbohydrate was 5% of the total COD. Fat and protein contributed 51% and 44% of the total COD of the wastewater respectively. The average concentrations of ammonia, total phosphorus, total suspended solids and alkalinity were 75 mg L-1, 34 mg L-1, 450 mg L-1 and 275 mg L-1 CaCO3 respectively. Maximum specific growth rates of heterotrophs and autotrophs were between 1.2-2.5 day-1 and 0.65-0.8 day-1. The heterotrophs yield coefficient was 0.63 on a COD basis.
Membrane bioreactors for final treatment of wastewater
Authors: Galil N.I. , Sheindorf Ch. , Stahl N. , Tenenbaum A. , Levinsky Y.
Published: May 2018

The full-scale existing treatment plant in a paper mill in Hedera, Israel, includes equalization, solids separation by either straining or by dissolved air flotation and biological treatment by activated sludge. The operation of the existing biological process is often characterized by disturbances, mainly bad settling, voluminous bioflocs, followed by wash-out of the biosolids. This paper summarizes the results obtained in a study based on a pilot plant including a membrane biological reactor (MBR) compared to the “conventional” activated sludge process in the aerobic treatment of the effluent obtained from an anaerobic reactor. During the pilot operation period (about 90 days after achieving steady state) the MBR system provided steady operation performance, while the activated sludge produced effluent characterized by oscillatory values. The results are based on average values and indicate much lower levels of suspended solids in the MBR effluent, 2.5 mg/L, as compared to 37 mg/L in the activated sludge. As a result, the total organic mater content was also substantially lower in the MBR effluent, 129 vs 204 mg/L as COD, and 7.1 vs 83 mg/L as BOD. The MBR enabled better nitrification. The ability to develop and maintain a concentration of over 11,000 mg/L of mixed liquor volatile suspended solids in the MBR bioreactor enabled an intensive bioprocess at relatively high cell residence time. As a result the biosolids which had to be removed as excess sludge were characterized by relatively low volatile/total suspended solids ratio, around 0.78. This could facilitate and lower the cost of biosolids treatment and handling. The results of this comparative study indicate that in the case of MBR there will be no need for further treatment, while after activated sludge additional filtration will be required. The study leads to the conclusion that MBR will be the best technology for aerobic treatment of the anaerobic effluent of the paper mill.
Molecular assessment of ammonia- and nitrite-oxidizing bacteria in full-scale activated sludge wastewater treatment plants
Authors: Robinson K.G. , Dionisi H.M. , Harms G. , Layton A.C. , Gregory I.R. , Sayler G.S.
Published: May 2018

Nitrification was assessed in two full-scale wastewater treatment plants (WWTPs) over time using molecular methods. Both WWTPs employed a complete-mix suspended growth, aerobic activated sludge process (with biomass recycle) for combined carbon and nitrogen treatment. However, one facility treated primarily municipal wastewater while the other only industrial wastewater. Real time PCR assays were developed to determine copy numbers for total 16S rDNA (a measure of biomass content), the amoA gene (a measure of ammonia-oxidizers), and the Nitrospira 16S rDNA gene (a measure of nitrite-oxidizers) in mixed liquor samples. In both the municipal and industrial WWTP samples, total 16S rDNA values were approximately 2-9 × 1013 copies/L and Nitrospira 16S rDNA values were 2-4 × 1010 copies/L. amoA gene concentrations averaged 1.73 × 109 copies/L (municipal) and 1.06 × 1010 copies/L (industrial), however, assays for two distinct ammonia oxidizing bacteria were required.
A new method for the fast determination of kinetic parameters in anaerobic digestion processes and application to textile wet processing wastewater
Authors: Feitkenhauer H. , Meyer U.
Published: May 2018

A new method for the fast and efficient determination of the anaerobic degradability and for the calculation of kinetic parameters is proposed. It is based on the idea that monitoring of the acidification step in the anaerobic degradation cascade is sufficient, as the subsequent steps (acetogenesis, methanogenesis) are well known processes dependent on the intermediate concentrations and not on the original substrate used. The investigation of the acidification is subdivided into two steps. In the first step, biomass is adapted to the new substrate in a continuously operated bioreactor. The second step, the only step monitored, is the acidification of the substrate (or wastewater) in a batch experiment. Three different methods to monitor the acidification were tested: gas chromatography (offline), on-line titration and monitoring of the base consumption (direct titration). The results of these methods were compared to ÒtraditionalÓ batch tests. It is shown that the simplest method (direct titration) revealed the most important information. The investigated substrates were selected pollutants of textile wet processing wastewater.
Elucidation mechanism of organic acids production from organic matter (grass) using digested and partially digested cattle feed
Authors: Sonakya V. , Raizada N. , Dalhoff R. , Wilderer P.A.
Published: May 2018

The process of anaerobic digestion is highly influenced by the environmental and operational factors like organic acids concentration and the reactor volume occupied by the feed material. The optimum level of organic acids is commonly assumed to be in the range between 2,500 and 3,500 mg/l for the anaerobic digestion process. It was observed that the production of total organic acids during hydrolysis of grass using cattle dung slurry (CDS) as the inoculum reached up to 4,850 mg/l in 6 days, while on the other hand it reached 5,700 mg/l within 4 days when rumen content was used as inoculum. The organic acids production continued to the 30th day in the case of rumen content, while in the case of CDS it stopped within 10 days because of pH drop. As compared to CDS the anaerobic digestion of grass with rumen content showed better degradation and biogas production with nearly 80% of methane and up to 80 and 95% reduction in chemical oxygen demand and organic acids respectively.
Effects of environmental endocrine disruptors on the sex differentiation in Korean rockfish, Sebastes schlegeli
Authors: Lee W.-K. , Lee K.-W. , Kwak E.-J. , Yang S.-W. , Yang K.-S. , Park J.-C. , Joo H.-S. , Lee W.-J. , Lee W.-B.
Published: May 2018

The effects of estradiol-17β, methyltestosterone, tributyltin, bisphenol A and 2,4-dinitrophenol on sex differentiation were investigated in the Korean rockfish, Sebastes schlegeli. The 51 day-old fry with undifferentiated gonads were fed with food containing the chemicals at 0.05, 0.5, 5, 50 and 100 μ/g diet for 29 days. Sex ratio and gonadal abnormality after the chemical treatment were determined by histological examination of gonads. In control group, the sex ratio of fry was 1:1.3 (female:male), and more males than females appeared. The sex of fry fed with estradiol-17β at 5, 50 and 100 μ/g diet was all females. Feminization of the fry was induced by exogenic estradiol-17β. In the methyltestosterone group, sex ratio of fry was 1:10.2 in 0.05 μ/g diet, 1:2.4 in 0.5 μ/g diet, 1:3.1 in 5 μ/g diet, 1:1.2 in 50 μ/g diet and 1:2.3 in 100 μ/g diet. Masculinization of the fry was induced by methyltestosterone at the lowest concentration. Furthermore, intersex of the fry was observed. The number of intersex fry was 23.3, 25.0 and 35.3 at 0.5, 5 and 50 μ/g diet of methyltestosterone, respectively. Sex ratio of bisphenol A group showed no difference with that of the control. The sex of fry fed with 2,4-dinitrophenol at 5, 50 and 100 μ/g diet was all females. 2,4-dinitrophenol should be considered as a new member of endocrine disruptors. In tributyltin group, the sex ratio of fry at 100 μ/g diet of tributyltin was 5.4:1. Tributyltin induced the feminization of the fry at the highest dose. Tributyltin showed an estrogenic effect in the Korean rockfish in contrast to an androgenic effect in gastropods.
A set of marine microalgae bioassays for the evaluation of biological water quality in enclosure areas in south of Spain
Authors: Garrido-Pérez M.C. , Acevedo-Merino A. , Nebot-Sanz E. , Sales-Márquez D.
Published: May 2018

The aim of this study has been the identification of the nutritive status (oligotrophy and eutrophy) in four enclosure areas from Gulf of Cadiz (Southwest Iberian Peninsula - Europe) by means of a battery of water column toxicity tests. The test organisms were four marine microalgaes which comprised a wide taxonomic range. Growth tests with receiving waters from the four study areas were carried out under two nutritive conditions; with and without additional nutrient-enriched medium. The results of both bioassays were used to define a new eutrophication index (IE). The IE index obtained presents a good correlation with the traditional physical-chemical parameters in the enclosure areas; nevertheless in open waters where the dilution processes are more important the results show less correlation.
Estimation of snow covered area for an urban catchment using image processing and neural networks
Authors: Matheussen B.V. , Thorolfsson S.T.
Published: May 2018

This paper presents a method to estimate the snow covered area (SCA) for small urban catchments. The method uses images taken with a digital camera positioned on top of a tall building. The camera is stationary and takes overview images of the same area every fifteen minutes throughout the winter season. The images were read into an image-processing program and a three-layered feed-forward perceptron artificial neural network (ANN) was used to calculate fractional snow cover within three different land cover types (road, park and roofs). The SCA was estimated from the number of pixels with snow cover relative to the total number of pixels. The method was tested for a small urban catchment, Risvollan in Trondheim, Norway. A time series of images taken during spring of 2001 and the 2001-2002 winter season was used to generate a time series of SCA. Snow covered area was also estimated from aerial photos. The results showed a strong correlation between SCA estimated from the digital camera and the aerial photos. The time series of SCA can be used for verification of urban snowmelt models.
Building capacity of the Baltic States to meet the EU Water Framework Directive through watershed demonstration projects
Authors: Vicory A. , Staniskis J. , Heath J. , Davenport T.
Published: May 2018

The Ohio River Valley Water Sanitation Commission (ORSANCO), in cooperation with the United States EPA, is completing it role in assisting the Baltic Countries of Estonia, Latvia, Lithuania and Kaliningrad Oblast, Russia with watershed management capacity building demonstration projects under the Great Lakes/Baltic Sea Partnership Program. The Countries of Estonia, Latvia and Lithuania view the skills gained through this program as important to their objective of complying with the European Union’s Water Framework Directive and thus facilitating accession into the European Union. The program also addressed Kaliningrad’s desire to work cooperatively with their neighboring countries concerning shared waters. Three watershed demonstration projects were designed and implemented, two of which involved joint country efforts: Parnu River (Estonia) modeling for nutrients and bacteria survey; river basin assessment and management planning for the Lielupe Basin (Latvia and Lithuania); and data base development and cooperative water quality survey and analysis for the Sesupe River (Lithuania and Kaliningrad). The benefits of the projects include enhancing the country’s technical skills and the forging of relationships, without which achieving effective watershed management will be difficult to achieve.
Strategic water planning for South East England: preparing for proposed development
Authors: Carroll B.A.
Published: May 2018

The South East of England has one of the fastest growing and economically active populations in Europe, with associated significant pressures from development, particularly housing and transport. Sustainable water management has been identified as a major issue for future development of the region. The South East England Regional Assembly and the Environment Agency have carried out a study to investigate the potential constraints that flood risk, water resources, and water quality may pose on development. The study aims to improve understanding in order to inform the revision of regional planning polices and suggest practical guidance for local authorities to implement such policies. Wide technical consultation was carried out with the Environment Agency, local planning authorities and development agencies. Threshold Assessment was investigated as a technique to assess the potential impacts on the environment of various levels of forecast growth within selected parts of the region. Initial results indicate the need for more strategic and better integrated planning which recognises environmental and development boundaries.
Identification of significant pressures and impacts upon receiving waters
Authors: Borchardt D. , Richter S.
Published: May 2018

This study gives a review on the process of identification of significant pressures and impacts, which is an important part of river basin planning and in particular for implementing the EU Water Framework Directive (WFD) (2000/60/EC). The questions: what is a “significant pressure” in terms of the WFD? which sources and driving forces have to be regarded? which data can be used? which pressure on a water body is significant? and which implications and requirements result from the identification process? - should be considered. The European Commission requires reporting from all Member States about the status of the water bodies within a river basin district and about the risk of failing the environmental objectives by the end of 2004. Therefore, a number of prevailing projects across Europe aim to develop a guideline on a common understanding of the most effective approach towards the identification of significant anthropogenic pressures, and the analysis of potential impacts including the identification of appropriate tools and models. In such a guideline suitable and intelligent criteria have to be developed in order to enable a uniform assessment of the anthropogenic pressures within a river basin district.
Treatment of phenolic wastewater using agricultural wastes as an adsorbent in a sequencing batch reactor
Authors: Lee K.-M. , Lim P.-E.
Published: May 2018

The objective of this study is to investigate the potential of the activated rice husk to be used as an alternative adsorbent to powdered activated carbon (PAC) in the simultaneous adsorption and biodegradation processes under sequencing batch reactor (SBR) operation to treat synthetic wastewater containing phenol, p-methylphenol, p-ethylphenol and p-isopropylphenol. The rice husk (PRH) was activated by pyrolysis at 600°C for 5 hours in a nitrogen atmosphere. Using the Langmuir model, the limiting adsorption capacities of PRH for the phenols were found to vary from 0.015-0.05 of those of PAC. The SBR reactors with and without adsorbent addition were operated with fill, react, settle, draw and idle periods in the ratio of 4:6:1:0.75:0.25 for a cycle time of 12 hours. For phenolic wastewater containing, 1,200 mg/L phenol, 1,200 mg/L p-methylphenol, 800 mg/L p-ethylphenol and 650 mg/L p-isopropylphenol, it was found that the biodegradation process alone was unable to produce effluent of quality which would satisfy the discharge standards of COD ≤ 100 mg/L and phenol concentration ≤1 mg/L. The addition of PAC in the ratio of PAC/phenolic compound at 0.095 g/g for phenol, 0.119 g/g for p-methylphenol, 0.179 g/g for p-ethylphenol and 0.220 g/g for p-isopropylphenol, can improve the effluent quality to satisfy the discharge standards. Equivalent treatment performance was achieved with the use of PRH at dosages of 2-3 times higher than those of PAC for all the phenolic wastewater studied. The increased adsorption capacity of PRH shown in the treatment indicates bioregeneration of the adsorbed surface during the treatment process.
Degradation of trace contaminants using coupled sonochemistry and Fenton's reagent
Authors: Jiang Y. , Waite T.D.
Published: May 2018

The degradations of phenol in air-equilibrated aqueous media were investigated using coupled sonochemistry and Fenton's reagent for a variety of operating conditions. The decomposition yields of phenol (100-500 mM) were substantially enhanced due to the addition of Fenton's reagent (FeSO4) into the solutions irradiated at 608 kHz with 30 W and with reaction temperature 25 ± 1°C. The decomposition process follows a pseudo-first-order reaction kinetics with respect to phenol concentration, and the rate constant of phenol disappearance observed increases by approximately 2-3 fold when FeSO4 concentration was between 400 and 1000 M at pH = 3.5 ± 0.2 (controlled by phosphate buffer) as a result of Fe(II) reaction with H2O2 enabling further production of additional OH• radicals. The results obtained here also indicate that the decomposition rate of aqueous phenol using coupled ultrasound and Fenton's reagent was strongly dependant on the initial concentration of reactant, the amount of Fe(II) added as well as the pH of solution. The optimal operating conditions for 100-500 mM phenol decomposition in the air-equilibrated aqueous media were obtained when FeSO4 concentration was between 400 and 1,000 mM with pH in the range 3.5-4.2 under ultrasonic irradiation at 608 kHz, 30 W and reaction temperature 25 ± 1°C.
Monitoring of water transfer from Katse Dam into the Upper Vaal river system: water utility’s perspective
Authors: Lepono T. , Du Preez H.H. , Thokoa M.
Published: May 2018

Water quality is of prime importance to Rand Water’s core business of ensuring a reliable supply of good quality drinking water to more than 10 million people. Rand Water has, therefore, implemented a water quality monitoring programme of the source water as well as the drinking water produced. The establishment of the Lesotho Highlands Water Transfer scheme necessitated the expansion of the monitoring programme. In 1996, Rand Water and Lesotho Highlands Development Authority (LHDA) signed an agreement to jointly develop an extensive water quality monitoring programme for the Lesotho Highlands Water Project (LHWP). Prior to this agreement, monitoring was mainly undertaken by consultants on behalf of LHDA in the main feeder rivers within the Katse Dam catchment (donor system). On the recipient system (Ash/Liebenbergsvlei), extensive physical and chemical monitoring was undertaken by Rand Water and Department of Water Affairs and Forestry (DWAF). Biological monitoring was however only carried out superficially prior to the release of water. Information gained from carrying out biological and chemical assessments clearly indicates that the water from LHWP has negatively impacted on the biological communities in the recipient system. The importance of detailed before and after biological and physio-chemical monitoring of both donor and recipient systems is emphasised.
Investigation of coastal morphological changes due to river basin characteristics by means of remote sensing and GIS techniques
Authors: Seker D.Z. , Goksel C. , Kabdasli S. , Musaoglu N. , Kaya S.
Published: May 2018

The Riva River is located on the Anatolian (Asian) side of Istanbul by the Black Sea coast, with a wonderful sandy beach and delta formation which has been selected as the study area. The Riva is the largest river in this region, which flows into the Black Sea and also gives its’ name to the area. The river carries some amount of sediments to the Black Sea. These particles cause considerable changes not only in the bed bathymetry and coastal boundaries of the river but also along the coastline of the Black Sea. The aim of this study is to determine these variations by means of satellite data and GIS. In the study, satellite images dated 1975, 1984, 1992 and 2001 have been used. At the end of the study, the possibility of observing bathymetric changes in front of the coastline by means of satellite data has been investigated and results were evaluated and visualised by means of GIS.
Phosphate and arsenate retention in sediments of the Anllóns river (northwest Spain)
Authors: Rubinos D. , Barral M.T. , Ruiz B. , Ruiz M. , Rial M.E. , Álvarez M. , Diaz-Fierros F.
Published: May 2018

We have studied the distribution and sorption behavior of phosphate and arsenate in bed-sediments of the Anllóns river (NW Spain). As a consequence of the intense gold-mining activity in the past, substantial amounts of arsenic were found in the river sediments. For phosphorus, higher concentrations were found near two sources of P pollution. Sorption isotherms were described by the Freundlich, Langmuir and Tempkin equations. In general, the sediments sorbed more P than As. The equilibrium P concentration (EPC) reveals that sediments act as a scavenger for soluble P; by contrast, equilibrium As concentration (EAC) values were high for the As-rich sediments and correlates well with total arsenic content. Amorphous Fe oxides content, organic matter and fraction of clay plus silt were the main properties of the sediments related with the sorption of arsenate and phosphate. The results obtained provide a first estimate of the sorption behavior and availability of the phosphate and arsenate anions in the sediments of the Anllóns river.
Recovery of acetic acid from waste streams by extractive distillation
Authors: Demiral H. , Ercengiz Yildirim M.
Published: May 2018

Wastes have been considered to be a serious worldwide environmental problem in recent years. Because of increasing pollution, these wastes should be treated. However, industrial wastes can contain a number of valuable organic components. Recovery of these components is important economically. Using conventional distillation techniques, the separation of acetic acid and water is both impractical and uneconomical, because it often requires large number of trays and a high reflux ratio. In practice special techniques are used depending on the concentration of acetic acid. Between 30 and 70% (w/w) acetic acid contents, extractive distillation was suggested. Extractive distillation is a multicomponent-rectification method similar in purpose to azeotropic distillation. In extractive distillation, to a binary mixture which is difficult or impossible to separate by ordinary means, a third component termed an entrainer is added which alters the relative volatility of the original constituents, thus permitting the separation. In our department acetic acid is used as a solvent during the obtaining of cobalt(III) acetate from cobalt(II) acetate by an electrochemical method. After the operation, the remaining waste contains acetic acid. In this work, acetic acid which has been found in this waste was recovered by extractive distillation. Adiponitrile and sulfolane were used as high boiling solvents and the effects of solvent feed rate/ solution feed rate ratio and solvent type were investigated. According to the experimental results, it was seem that the recovery of acetic acid from waste streams is possible by extractive distillation.
Predicting near-shore coliform bacteria concentrations using ANNS
Authors: Lin B. , Kashefipour S.M. , Falconer R.A.
Published: May 2018

Details are given of the application of Artificial Neural Networks (ANNs) to predicting the compliance of bathing waters along the coastline of the Firth of Clyde, situated in the south west of Scotland, UK. Water quality data collected at 7 locations during 1990-2000 were used to set up the neural networks. In this study faecal coliforms were used as a water quality indicator, i.e. output, and rainfall, river discharge, sunlight and tidal condition were used as input of these networks. In general, river discharge and tidal ranges were found to be the most important parameters that affect the coliform concentration levels. For compliance points close to the meteorological station, the influence of rainfall was found to be relatively significant to the concentration levels.
The competition between PAOs (phosphorus accumulating organisms) and GAOs (glycogen accumulating organisms) in EBPR (enhanced biological phosphorus removal) systems at different temperatures and the effects on system performance
Authors: Erdal U.G. , Erdal Z.K. , Randall C.W.
Published: May 2018

It is well known and firmly established that the rate of chemical and biochemical reactions slow down as temperature decreases. Nevertheless, several studies have reported that the efficiency of enhanced biological phosphorus removal (EBPR) improves as temperature decreases. However, several recent studies have reported that EBPR reaction rates decrease with temperature decrease in accordance with the Arrhenius relationship. This study was designed to more thoroughly investigate this controversy using two UCT plants fed with a synthetic wastewater consisting primarily of acetate as the COD form, and a small amount of supplemental yeast extract. Experiments were performed over temperatures ranging from 5 to 20°C. The results showed that, even though the kinetic rates decrease as temperature decreases, EBPR systems perform better at colder temperatures. The reason for better system performance is apparently related to reduced competition for substrate in the non-oxic zones, which results in an increased population of PAOs and, thus, greater EBPR efficiency. The proliferation of PAOs apparently occurs because they are psychrophilic whereas their competitors are not. The experiments showed that the EBPR sludges accumulated high concentrations of both PHA and glycogen at 20°C, but accumulated more PHA and much less glycogen at 5°C. Although the results could be interpreted as the result of changes in the PAO-GAO competition, Mann-Whitney non-parametric comparisons of transmission electron microscopy examinations revealed no indication of the presence of GAOs population under any temperature conditions. Regardless, mass balances of the glycogen data showed that the involvement of glycogen is less at cold temperature, even though EBPR was greater. Unlike current EBPR models (e.g. Mino model), the results suggest that glycogen metabolism is not a precursor for EBPR biochemistry. The results also indicate that temperature not only may cause selective pressure on the dominant organisms, but also may force them to use a different metabolic pathway as temperature decreases.
Evaluation of influent prefermentation as a unit process upon biological nutrient removal
Authors: McCue T. , Shah R. , Vassiliev I. , Liu Y.-H. , Eremektar F.G. , Chen Y. , Randall A. A.
Published: May 2018

The objective of this NSF sponsored research was to provide a controlled comparison of identical continuous flow biological nutrient removal (BNR) processes both with and without prefermentation in order to provide a stronger, more quantitative, technical basis for design engineers to determine the potential benefits of prefermentation to EBPR in treating domestic wastewater. Specifically, this paper focused upon the potential impacts of primary influent prefermentation upon BNR processes treating septic domestic wastewater. This study can be divided into two distinct phases - an initial bench-scale phase which treated septic P-limited (TCOD:TP>40) wastewater and a subsequent pilot-scale phase which treated septic COD-limited (TCOD:TP<40) wastewater. The following conclusions can be drawn from the results obtained to date.•Prefermentation increased both RBCOD, SBCOD and VFA content of septic domestic wastewater.•Prefermentation resulted in increased biological P removal for a highly septic, non-P limited (TCOD:TP<40:1) wastewater. However, in septic, P-limited (TCOD:TP>40:1) wastewater, changes in net P removal due to prefermentation were suppressed by limited P availability, even though P release and PHA content were affected.•Prefermentation increased specific anoxic denitrification rates for both COD and P-limited wastewaters, and in the pilot (COD-limited) study also coincided with greater system N removal.
Induction of denitrification in a pilot-scale trickling filter by adding nitrate at high loading rate
Authors: Vanhooren H. , De Pauw D. , Vanrolleghem P.A.
Published: May 2018

Oxygen transferred from the liquid phase into a biofilm can be used for aerobic degradation of organic matter and for nitrification. A second possible pathway for the removal of organic matter is denitrification in anoxic zones deeper in the biofilm. At high organic loading rates with insufficient oxygen supply to the biofilm, denitrification could be induced by providing the biofilm with external nitrate. This possibility was tested in a pilot-scale trickling filter by adding a pulse of nitrate to a highly loaded trickling filter. The experiment showed that denitrification can indeed be induced by adding nitrate at high loading conditions and that this way a considerably increased substrate removal capacity can be obtained. The fact that denitrification occurred was confirmed by the increased production of CO2 from bioconversion processes, without a major change of the O2 consumption. The simplified mixed-culture biofilm model developed by Rauch et al. was extended for the description of off-gas measurements and was able to describe the results of the experiment very well.
Partial nitrification in a high-load activated sludge system by biofilter backwash water recirculation
Authors: Melicz Z.
Published: May 2018

The South-Budapest Municipal Wastewater Treatment Plant (SBWWTP) based on the high-load activated sludge process (AS) was upgraded into nutrient removal in 1998-1999 in Hungary. Biofor® type nitrifying (NP) and denitrifying (DN) biofilters were implemented for nitrogen removal downstream of the (AS) stage in order to meet the required effluent standards characterized by 50 mgCOD l-1, 10 mgBOI5 l−1, 10 mgTN l−1, 1 mgTP l−1 and 35 mgTSS l−1. Phosphorus removal is obtained by chemical addition. The study presented sums up the performance of the upgraded plant throughout 25 months. Besides the efficient pre-denitrification obtained in the AS basin, significant ammonium oxidation was observed in the aerated zone, upon the introduction of recirculation of nitrate rich water and backwash water. The introduction of biofilter backwash water, containing nitrifying biomass, has generated significant ammonium conversion in the aerated basins, where nitrification was observed previously to a very limited extent. Process parameters of the AS stage were: aerobic sludge age of 1.5-2.0 days, 1.5 hours hydraulic retention time, specific sludge load of 1.1 kgCOD kgMLSS−1 d−1. The nitrification in the AS tank has significantly reduced below 16°C, however, denitrification efficiency was not as highly dependent upon temperature during the investigated period. The paper investigates the nitrogen balance of the plant in two aspects: (i) the effects of seeding on nitrification in the high load AS reactor and (ii) pre-denitrification potential in the anoxic zone of the AS tank of the pre-settled wastewater.
Phased upgrading for nitrogen removal - a low cost approach
Authors: Solley D. , Armstrong M.
Published: May 2018

A phased approach has been adopted for upgrading the Luggage Point WWTP for nitrogen removal. Luggage Point WWTP (900,000 EP) is the largest plant operated by Brisbane Water. Management actions recommended by the South East Queensland Wastewater Management Strategy require the effluent total nitrogen levels to be reduced to less than 5 mg/L (50th percentile) by 2005. Luggage Point WWTP originally featured primary settling and a completely nitrifying activated sludge process. Effluent total nitrogen levels from the plant averaged 27 mg/L. Characteristics of the wastewater are highly variable, with primary settled wastewater having a COD/BOD5 ratio averaging 2.5, a TKN/COD ratio averaging 0.12 and effluent non-ammonia TKN averaging 1.8 mg/L (but up to 5 mg/L). The upgrade presented a substantial challenge, due to the limited available substrate for denitrification, a significant level of unbiodegradeable nitrogen and the low existing bioreactor HRT. The phased upgrading strategy was adopted to overcome these challenges most effectively and at low cost. The first stage of the upgrade included modifications to the existing plant infrastructure, without constructing new tankage. The existing bioreactors have been retro-fitted using a five stage Bardenpho nutrient removal process, incorporating significant flexibility. The first phase upgrade has been commissioned and preliminary results indicate that the effluent total nitrogen has been reduced below the required first phase target of 8 mg/L. This represents a reduction of 3 tonnes of nitrogen per day entering Moreton Bay. The process is also operating with good stability and with excellent sludge settleability. The first phase of the upgrade will be completed for $AUS25M, which represents a low cost of $28 per equivalent person. Further upgrade works are likely to include separate treatment of the digested sludge dewatering centrate and advanced control of the biological process. The upgrade of Luggage Pt WWTP has shown that low effluent nitrogen can be achieved at low cost, through optimum utilisation of existing assets and a phased approach to modifications.
Structure-function dynamics and modeling analysis of the micro-environment of activated sludge floc
Authors: Li B. , Bishop P.
Published: May 2018

Biodegradation by microorganisms and mass transfer resistance in the micro-environment of activated sludge floc can cause changes in substrate and dissolved oxygen concentrations within the floc and can contribute to stratification of microbial processes inside the flocs. In this study, an integrated model of the microenvironment of the activated sludge floc was developed for floc from wastewaters from several sources and of varying strengths for dynamic simulation of the combined biological processes of COD and nitrogen removal. The model simulation results and measured profiles show the heterogeneous and gradient-governed microenvironment of activated sludge floc under different substrate and bulk oxygen concentrations. The substrate concentration increase zones inside the floc were present in all activated sludge floc from the Miller Brewing Co. wastewater treatment facility (high pollutant strength), with an oxygen penetration depth of only 0.15 mm into the outer layer. The anoxic and substrate concentration increase zones also dominated in the activated sludge floc from the Mill Creek Plant influent (medium pollutant strength), with the outer layer (0.20 mm) participating in the metabolism of the pollutants. The radius of the substrate concentration increase zone inside the sludge floc decreased with pollutant removal along the length of the tank. When the pollutant concentration in the bulk wastewater was low (Muddy Creek Plant), the substrate concentration increase zone disappeared; the whole floc was aerobic and in a high redox status. Our experiments and model analyses demonstrate that the microorganisms' structure-functions inside activated sludge floc change with the bulk substrate concentration and dissolved oxygen concentration.
Treatment of slaughterhouse wastewater using an activated sludge/contact aeration process
Authors: Chen C.-K. , Lo S.-L.
Published: May 2018

This study combines a two-phase biological treatment system of activated sludge/contact aeration process by adding biological contact filters into the rear sector of the activated sludge aeration tank of the slaughterhouse wastewater treatment plant. This system keeps the advantages of complete mixing of substrates and microorganisms and flexible operation of the activated sludge process, and increased biological phase, less sludge, process stability and good settleability of sludge of the contact aeration process. This system could avoid the defects of sludge bulking, increased sludge production and difficult operation of the activated sludge process, and system clogging and rigid operation of the contact aeration process. Because suspended microorganisms are flowing into the contact aeration system, which then degrade or suspend within the biological contact filters after being adsorbed by the fixed biological film, on which partial bio-solids will act as seeding microorganisms. Suspended microorganisms and the dropped biological film will settled in the secondary settling tank, then reflux into the activated sludge aeration tank. The partial dropped biological film will decompose in the activated sludge aeration tank to achieve the function of decreasing sludge. Large specific gravity and good settling ability of biofilm sludge will provide better effluent quality. It has been proven through a practical experiment at a slaughterhouse wastewater treatment plant in Taiwan, that the activated sludge process effluent COD value of 150-200 mg/L and SS value of 80-100 mg/L were decreased to around 40 mg/L and 22 mg/L, respectively, after changing its system to the two-phase biological treatment system of activated sludge/contact aeration process.
Assessment of sediment toxicity by metal speciation in different particle-size fractions of river sediment
Authors: Lin J.G. , Chen S.Y. , Su C.R.
Published: May 2018

Mobility and toxicity of metals associated with sediments are generally affected by metal speciation and granular compositions. Due to the various speciation patterns of heavy metals in sediments, it is not reliable to assess the potential toxicity of heavy metals on the aquatic environment with the total concentrations of heavy metals in sediments. The purposes of this study were to investigate the distribution of metal speciation in different particle-size fractions of sediments collected from two rivers (the Ke-Ya River and Ell-Ren River) in Taiwan, and to assess their potential toxicity to the aquatic ecosystem. Metals in the exchangeable, carbonate-bound and Fe/Mn oxide-bound forms obtained by sequential extraction were considered to be mobile and related with anthropogenic pollution. The degree of metal pollution and potential toxicity of sediments were higher in the lower reaches of both rivers. The metal speciation in sediments had a bimodal distribution over particle-size fractions. Heavy metals were subject to accumulation in the silt/clay fraction (<25μmm) and coarse sand (420-2,000μmm). By normalizing the sum of the exchangeable, carbonate-bound, and Fe/Mn oxide-bound metals, it suggested that the potential toxicity to the aquatic ecosystem was caused by the fine sediments as well as coarse sediments.
The PPL filtration treatment for highway runoff
Authors: Kimura S. , Matsui S. , Simuzu Y. , Lee B.-C. , Shinya M.
Published: May 2018

The purpose of this research is to design a device which can treat highway runoff, especially runoff during initial rainfall with high pollution intensity, by connecting it with the draining grid sink of a drainage ditch on a highway, through which runoff flows. Porous polypropylene (PPL) particles were used as a treatment agent. The device treated highway runoff during initial rainfall by filtration and adsorption. It had a capacity to treat highway runoff in an area of 7.0 m × 20.0 m when rainfall intensity was up to10 mm/hr. Two cases of rainfall intensity were set for the experiment: 5 and 10 mm/hr. The relationships between the efficiency of SS and COD removals and the rainfall intensity were investigated. Using artificial highway runoff with constant flow and SS concentration, results of 70% or more of SS removal with 5 mm/hr and 50% or more with 10 mm/hr were obtained. COD removal efficiency was about 90% of SS removal efficiency. This device was effective to remove non-point source pollutants in runoff on highways.