bluuebunny/crossref_metadata_2025 huggingface dataset:
Multivariate micropollutants analysis in marine waters
Authors: Librando V. , Magazzù G. , Puglisi A.
Published: May 2018

The monitoring of water quality today provides a great quantity of data consisting of the values of the parameters measured as a function of time. In the marine environment, and especially in the suspended material, increasing importance is being given to the presence of organic micropollutants, particularly since some are known to be carcinogenic. As the number of measured parameters increases examining the data and their consequent interpretation becomes more difficult. To overcome such difficulties, numerous chemometric techniques have been introduced in environmental chemistry, such as Multivariate Data Analysis (MVDA), Principal Component Analysis (PCA) and Partial Least Squares Regression (PLSR).

The use of the first technique in this work has been applied to the interpretation of the quality of Augusta bay, by measuring the concentration of numerous organic micropollutants, together with the classical water pollution parameters, in different sites and at different times. The MVDA has highlighted the difference between various sampling sites whose data were initially thought to be similar. Furthermore, it has allowed a choice of more significant parameters for future monitoring and more suitable sampling site locations.
Recent technical and scientific initiatives for the management of the adriatic sea problems
Authors: Chiaudani G. , Premazzi G.
Published: May 2018

The main eutrophication-related phenomena in the Adriatic Sea such as phytoplankton blooms, anoxia, macroalgae proliferation, gel production and toxic algae are briefly presented. A cost-benefit evaluation of different phosphorus control strategies for the recovery of the northern Adriatic coastal waters is summarized. The ongoing and planned activities considered by the Italian Authorities are illustrated. They include the definition of a research programme and an operative research project (responsibility of the Ministry for the Scientific Research and University) and the development of the Master Plan (responsibility of the Ministry of the Environment) to provide decision makers with a sound information to implement policies for the restoration of the marine ecosystem. The general objectives of the research programme are: a) to maximize effectiveness of the research efforts aiming to be consistent with real needs, b) to eliminate unnecessary programmes; c) to ensure optimal use of existing infrastructures, d) to allow the development of a sound Master Plan and e) to promote cooperation with national and international programmes. The research programme recognizes seven topics, i.e. physical oceanography and dynamic characters, nutrients, toxic substances, biological agents, modification of marine habitats, present status of the Adriatic ecosystem and human health. For each item priorities for action are indicated. Finally, the goals of the Master Plan (responsibility of the Ministry for the Environment) are listed. They include the definition of a feasible project for the restoration of the basin using alternative methods of intervention, taking into consideration the compatibility between the predicted uses of the waterbody, the assessment of the efficiency of the predicted measures in relation to the use of the resources on one hand, and the priorities for the same measures on the other.
Using an array of ultrasonic velocity transducers to improve the accuracy of large sewer mean velocity measurements
Authors: Hughes A. W. , Longair I. M. , Ashley R. M. , Kirby K.
Published: May 2018

Portable in-sewer Doppler velocity measuring equipment has been available for a number of years. However in large sewers (typically greater than one metre diameter) the accuracy of these devices for large flow depths can be very poor. This paper describes a system, developed by the authors, that enables the determination of a velocity profile across the section of the flow in a large sewer. The velocity profile information obtained can then be used to determine a more accurate estimation of the mean velocity of flow in the large sewer.

In the paper the hardware and software developed to form the Doppler Transducer Velocity Array System is discussed. Installation of the system in a large sewer and subsequent field testing of the system are also discussed, with results of the field testing included. The paper also shows how the results obtained were used to produce 3-dimensional surface plot graphs that show the variation of velocity against time across a section of the sewer flow.
Portable sewage flow sensors - their calibration and accuracy
Authors: Watt I. A. , Jefferies C.
Published: May 2018

An accurate assessment of flows is essential for any study of the hydraulic performance of a sewer system or the pollutant removal efficiency of an effluent treatment plant. Flow measurement relies either on fixed flumes, usually at the inlet to treatment works, or on portable in-sewer depth and velocity sensing equipment which is periodically calibrated to check on its accuracy. It is becoming increasingly important to optimise the operation of sewage treatment works both to ensure consent standards are met, and to minimise the total pollution load reaching the environment. Consequently, accurate flow measurements at a number of locations are required to complement quality performance measurements.

The field equipment normally used for measuring flows in either full or part-full pipes employs the ultrasonic Doppler-shift principle for mean velocity, and some form of depth measurement, typically a pressure transducer. The quality and accuracy of the data obtained may be highly variable, and detailed quality assurance checks can be of great value. This paper presents the results of a number of studies in which the accuracy of velocity measurement using doppler-shift has been an important factor. Assessments of the overall accuracies and reliability of the flow measurement equipment are assessed by examining data from a number of studies. Factors such as the frequency of calibration, the range of flow states at which calibration has been carried out and the concentration of suspended solids were all found to be important. Ranges of accuracy of data gathered are presented.
Requirements with respect to on-line analyzers for N and P
Authors: Schlegel S. , Baumann P.
Published: May 2018

For some years now, measuring instruments have been employed at wastewater treatment plants in Germany to continuously monitor ammonia (NH4), nitrate (NO3) and phosphate (PO4). Altogether, almost 3,000 monitoring units are currently in use at a total of approximately 600 treatment plants of all sizes. In addition to continuously monitoring the treatment plant effluent and individual treatment processes, these allow the adjustment and control of plant units and, thus, a saving in operating costs, particularly with respect to the consumption of energy and chemicals.

In addition to characteristic data on the instruments, investment and operating costs play a major role when deciding to purchase measuring instruments of this type.

Therefore, the German Technical Wastewater Association's (ATV) working group on the “Automation of Wastewater Treatment Plants” resolved to prepare, within the framework of the ATV rules, a code of practice on “Requirements with respect to On-line Analyzers for Nitrogen and Phosphorus Compounds” (M 269). The purpose of this is to provide planners, operators and public authorities with advice on the design and reliable operation of on-line analyzers and the appurtenant peripheral equipment. The present text describes the essential contents of M 269.
Experiences with on-line measurements at a wastewater treatment plant for extended nitrogen removal
Authors: Nyberg U. , Andersson B. , Aspegren H.
Published: May 2018

On-line sensors have been used at the Klagshamn treatment plant to measure the concentration of suspended solids in the raw wastewater, in the primary effluent and in the secondary effluent. By means of the sensors the short-term performance of the primary and the secondary treatment have been evaluated. The sensors are important when the total discharges of pollutants from the plant are to be considered during storm water events.

Parallel on-line measurements and laboratory analyses of grab samples have shown that the used sensor type, based on NIR technique, reflects the concentrations rather well. The on-line measurement in the raw wastewater is rather unreliable due to clogging which means that using this application for control can be questioned.
Process development by full-scale on-line tests and documentation
Authors: Bundgaard E. , Nielsen M. K. , Henze M.
Published: May 2018

The use of on-line sensors in BNR plants has given a lot of information on the dynamic reaction of such systems. This has allowed of new methods of operation. This new ATS operation has been tested and shows a big potential for increasing the hydraulic loading on existing plants.
Quantifying the inherent uncertainty in the quantity and quality of domestic wastewater
Authors: Friedler Eran , Butler David
Published: May 2018

Results from two surveys in S.E. England are used to illustrate and quantify the inherent uncertainty in the quantity and quality of domestic wastewater at the fundamental level of discharges from domestic appliances. The uncertainties in three principal areas are elucidated. Volumetric discharges are shown to vary significantly for several appliances particularly when used in “running to waste” mode. Pollutant load also varies and information is presented for a number of different appliance-pollutant combinations. The frequency of use is known to vary throughout the day, but figures are presented to quantify the extent of the spread of the data during each hour of the day. A means of integrating the various elements of uncertainty is proposed. Quantification should enable better control of treatment plants and improve forecasting of the influence of combined sewer overflows on receiving waters, hence enhancing the management of the associated risk.
Competition of methanogenic and sulfidogenic bacteria
Authors: Visser A. , Hulshoff Pol L. W. , Lettinga G.
Published: May 2018

The competition of acetotrophic methanogenic bacteria (AMB) and acetotrophic sulfidogenic bacteria (ASRB) was studied by assessing growth rates, activities and acetate and sulfate affinities at different pH levels and sulfide concentrations in batch reactors. Both anaerobic granular sludge and suspended anaerobic sludge were tested. The results indicate that at pH-levels below 6.9 AMB will outcompete ASRB, whereas above a pH of 7.7, ASRB will win the competition. If ASRB and AMB are present in granular sludge growth will be found in a wider pH-range than if they are present as suspended sludge. The affinities for acetate and the sulfide toxicity are dependent on the sludge form as well. In granular sludge the acetate affinities of ASRB and AMB are comparable, whereas in suspended sludge ASRB show a lower affinity than AMB. With respect to sulfide toxicity, the results indicate that above pH 7 sulfide inhibition in granular sludge is caused by the total sulfide concentration, while in suspended sludge the free H2S-concentration determines the toxicity. At high pH-levels growth is stronger inhibited than the activity.
Anaerobic treatment of Municipal Solid Waste
Authors: Plaza G. , Robredo P. , Pacheco O. , Saravia Toledo A.
Published: May 2018

This paper discusses the present state of Municipal Solid Waste (MSW) disposal in Argentina, focusing on the particular situation of the city of Salta, and suggests the future trend of the anaerobic treatment of this residue.

Source-sorted household solid waste was determined by means of a statistical design. Municipal solid waste produced 147,103 kg per day +/- 6.7%, the major portion corresponds to the biodegradable organic fraction (55.4%). The plastic, metal, paper, glass, and other material production was also evaluated.

The organic municipal waste was chemically and biologically characterized, in order to study its behaviour during anaerobic digestion. The ratio normally found in organic fractions from MSW in Salta, Argentina, was in the optimum range which is 126:7:1 (C:N:P, w/w). The stability of the anaerobic process was analized in a 18 liter batch reactor. Its pH, biogas production, alkalinity, and volatile fatty acid production was determined.

Although the work has been carried out at a small scale it appears to be sufficiently promising to encourage further work at a larger scale.
An equation for the empirical design of anoxic zones used to eliminate rising sludges at nitrifying activated sludge plants
Authors: Sarioglu M. , Horan N.
Published: May 2018

Anoxic zones are designed for the removal of nitrogen in nitrifying activated sludge plants. This can be carried out either to achieve a nitrogen discharge consent or to eliminate the problem of rising sludges. The rising sludge problem is mostly encountered in medium and small size plants in warm conditions and there is limited information as to the appropriate design of anoxic zones to protect against rising sludges in the secondary sedimentation tanks. Therefore a series of batch experiments were undertaken in order to establish the critical concentration of nitrate-nitrogen which causes rising sludge in the secondary settling tank and the effect of environmental factors such as temperature (15°C to 30°C) and residual carbon source (100 to 600 mg/1 COD) were examined. Based on the results of these experiments an empirical equation was presented which can be used to size an anoxic zone to eliminate rising sludges. The application of this equation at full-scale plants is discussed.
Environmentally friendly method in reactive dyeing of cotton
Authors: Knudsen Hans Henrik , Wenzel Henrik
Published: May 2018

The recipe for reactive dyeing of cotton can be divided into three steps: the pretreatment, the dyebath and the final rinse. The consumption of chemicals and water in the rinse has been found to be considerable: three quarters of the total COD discharge of the recipe have relations to auxiliary chemicals used and three quarters of the total water consumption have relation to the rinse. The improvement potential in the rinsing procedure were found to be considerable, and the newly developed recipe focuses on improvements in the rinse.

Tests with the new recipe have documented that neutralization, detergents and complexing agents can be left out completely with no adverse effect on product quality. All recognized tests of fastness and shade have been performed and evaluated in cooperation with the dyehouses.

More than 50 full-scale dyeing experiments have been carried out in jets, overflow and drum batch machines. The experiments include 25 different reactive dyestuffs, among these azo, anthrachinon, phtalocyanin and formazan dyestuffs, including both monoreactive and bireactive dyestuffs of which 15 had the vinyl sulfone as reactive group. The dyestuffs have been combined in 20 different recipes covering very light to very dark shades.

Hot membrane filtration of the hot rinsing water has been investigated in parallel projects and it is documented that membrane filtration saves chemicals, water and production time, and also gives large energy savings in one new recipe.
Variability of species sensitivity to complex mixtures
Authors: Pedersen Finn , Petersen Gitte I.
Published: May 2018

In Denmark, as well as in a few other countries, the regulatory practice for granting permits for discharge of industrial waste water is based on evaluation of the potential effects of both the individual chemical substances in the waste water and the complex waste water itself by establishing “predicted-no-effect-concentrations” (PNECs). The present study was initiated in order to establish an extrapolation method for deriving PNECs for complex mixtures. The toxicity of 5 complex mixtures comprising from 5 to 20 different substances was tested with 5 different species/test systems: the green alga Rhaphidocellis subcapitata, daphnia (Daphnia magna), zebra fish (Brachydanio rerio), duckweed (Lemna minor) and Microtox (Vibrio fischeri). The results of the tests showed that the differences in sensitivity of the test species were considerably lower (5-12 times) than was the case for the individual substances present in the complex mixtures. Thus, based on the differences in sensitivity of the species, application factors for complex mixtures are proposed. Moreover, the results showed that the joint toxicity of the complex mixtures could be described by assuming that the toxicity of the individual substances in the mixtures was more or less additive.
Comparison of biodegradability assessment tests for chemical substances in water
Authors: Gotvajn Andreja Žgajnar , Zagorc-Koncan Jana
Published: May 2018

Assessment of biodegradability of specified compounds or wastewaters is an important guide to estimate their behavior in natural aquatic environment. Multilevel protocol for biodegradability assessment was proposed in the European Union to unify tests in different European countries. The protocol begins with tests for ready biodegradability, which are follosed by inherent biodegradability tests and the multilevel protocol is completed with simulation tests. The three-level tests are differentiated by procedure, concentration of test compound, amount and source of inoculum used. The comparisons of biodegradability tests, one standardized from zero level and one standardized from level one and their non-standardized modifications were made for different test substances to estimate the differences between them and to estimate the meaning of multilevel biodegradability testing. It was pointed out that, due to various biodegradation testing levels, differences between test results occur. The main ones are: the lag phase, the biodegradation rate and the final level of biodegradation.
Remediation of PCB-containing sediments using surface water diversion “dry excavation”: a case study
Authors: Praeger Thomas H. , Messur Stuart D. , DiFiore Richard P.
Published: May 2018

Remediation of contaminated sediments presents an on-going challenge in the efforts toward improved water quality and environmental restoration. Faced with this challenge, Mercury Marine recently selected a remedial alternative that included diverting creek flow and removing approximately 5,900 in-situ cubic meters of sediments containing PCBs from an impoundment in Cedar Creek. The regulatory objective was to remove all sediment containing PCBs “to the extent practicable” from an 180-meter stretch of the impoundment.

A remedial investigation was conducted to collect the data necessary to characterize the site and prepare a remedial design. Technical issues involved with dry excavation that were critical to implementing this alternative included: channel diversion, sediment characterization, pond dewatering, wastewater treatment, groundwater infiltration, surface water run-off, and sediment removal, handling and disposal.

Mercury Marine and its engineering staff found sediment removal by dry excavation to be a labor intensive and costly means of remediating the PCB-affected sediments at this site. Before implementing dry excavation at any site, owners, consultants, and regulatory agencies must realize the many limitations of this alternative and give special consideration to site conditions, engineering, and planning.
Seasonal variation of metal contamination of riverine sediments below a copper and sulphur mine in South-East Ireland
Authors: Herr Claudia , Gray N. F.
Published: May 2018

The discharge of acid mine drainage (AMD) from the abandoned sulphur and copper mines at Avoca (S.E. Ireland) results in the formation of ochreous deposits on the river substrate. Sediment sampling was carried out intensively during June and August, 1994 and again during March and April, 1995 to investigate seasonal variation of Fe, Cu and Zn concentration in riverine sediments of the receiving water (Avoca River). Temporal and spatial variations indicate that, apart from pH, hydrological factors play a major role in metal accumulation of highly energetic river systems. Zinc adsorption and desorption of “ochre” is chiefly regulated by pH, while Cu removal seems to be primarily by co-precipitation with iron. Basic considerations with regard to sampling techniques are discussed.
Hepatic enzymatic activities of the european eel Anguilla anguilla as a tool for biomonitoring freshwater streams: laboratory and field caging studies
Authors: Fenet H. , Casellas C. , Bontoux J.
Published: May 2018

Hepatic monooxygenase activity and conjugation enzyme activity were studied in young european eel (Anguilla anguilla). Laboratories studies were performed by treatment with β-naphtoflavone (β-NF). Two sources of eels, wild and reared eels were compared during a time-course study. MO activities measured as 7-ethoxyresorufin O-deethylase (EROD) were induced by β-NF, peak values were reached 2 and 4 days after treatment. The time-course induction of EROD activity was similar for wild and reared eels. In contrast, the conjugation reaction enzymes measured as glutathione-S-transferase (GST) didn't respond to this treatment.

During field studies, EROD and GST activities were studied in wild and reared eels held in cages upstream and downstream of a PAH polluted area. Similar induction of EROD activity was observed in the polluted site after 14 days of caging. The period of caging was studied and EROD activities were significantly induced in wild eels caged in the polluted site after 7 and 14 days. GST activities were not affected by the caging in the polluted site. The results indicate the usefulness of EROD activity as a biomarker of PAH contamination in the model of wild eels caging in the field.
Ammonia removal in a pilot-scale WSP complex in Northeast Brazil
Authors: Soares J. , Silva S. A. , de Oliveira R. , Araujo A. L. C. , Mara D. D. , Pearson H. W.
Published: May 2018

Ammonia removal was monitored in a waste stabilisation pond complex comprising ponds of different geometries and depths under two different operational regimes. It was found that a high degree of ammonia removal commenced in the secondary maturation ponds, with the highest removals occurring in the shallowest ponds as a consequence of improved aerobic conditions. The tertiary maturation ponds produced effluents with mean ammonia concentrations of < 5 mg N/l, the maximum permitted recommended by Brazilian environmental legislation for the discharge of effluents of wastewater treatment plants into surface waters. Ammonia removal in the secondary facultative and maturation ponds could be modelled using equations based on the volatilization mechanism proposed by Middlebrooks et al. (1982).
Production of valuable products from organic waste streams
Authors: van der Westhuizen T. H. , Pretorius W. A.
Published: May 2018

A process was developed at the University of Pretoria through which it became possible to simultaneously purify organic effluents and produce a constant quality Single Cell Protein (SCP) product under non-aseptic conditions. Performance of the process as applied to a sugar-furfural effluent is described. The organism selected was Aspergillus fumigatus, a thermotolerant filamentous fungus. Typical yield is 0.56 g biomass per g COD utilized. The amino acid profile of the biomass compares well with other edible protein sources. It was possible to reduce the COD concentration in the effluent from ± 8000 mg/L to ± 150 mg/L.
Microbial technology for management of phenol bearing dyestuff wastewater
Authors: Kanekar Pradnya , Sarnaik Seema , Kelkar Anita
Published: May 2018

Environmental pollution caused by dyestuff industry wastewater is two-fold since it contains toxic chemicals like phenol, aniline etc. and also imparts the colour of the dye manufactured. For management of dyestuff wastewater, microbial technology becomes a novel approach since microorganisms have the characteristic ability to break down aromatic compounds and decolourize the dyes.

Microbial treatment of a dyestuff wastewater containing phenol and methyl violet was studied at the site of a dye factory near Pune in a fixed film bioreactor. The bioreactor consisted of a rectangular cement concrete tank of dimensions 9.5 m length × 7.3 m breadth × 1.5 m height and brick pieces of size 10 cm × 8 cm × 6.5 cm used as supporting media for formation of microbial film. A mixed culture of Pseudomonas alcaligenes (phenol degrader) and Pseudomonas mendocina (decolourizing methyl violet) grown in the dyestuff wastewater was spread on brick media. After formation of a microbial film on brick media, the dyestuff wastewater was recycled in form of a shower through the brick bed for 24, 48 and 72h. The influent loading rate was 1.44 m3/m2 brick bed area per day. The phenol and Chemical Oxygen Demand (COD) loading rates were on average 0.9 kg phenol/m2/day and 5.67 kg COD/m2/day respectively.

The performance of the microbial degradation evaluated for a period of 68 days showed 97.5%, 63%, 54.4% and 51% removal in phenol, methyl violet (MV) content, COD and Total Organic Carbon (TOC) respectively in 24 hours of recycling and marginally enhanced in 48 and 72 hours.

The microbial technology was thus effective in removal of phenol and the dye from dyestuff wastewater.
Evaporation phenomenon as a waste management technology
Authors: Duarte E. A. , Neto I.
Published: May 2018

The problems concerned with waste management abound in most regions of the world, and so, efforts must be made to assess the global level of pollution and to understand the major factors involved in order to propose efficient waste treatment technologies. This must be compatible with environmental and economic conditions and appropriate to semi-urban settlements, isolated communities and a variety of industrial situations.

The main purpose of this paper is to present recent waste management technology as an alternative solution to traditional treatment systems in regions where those systems are not economically or technically feasible, using for this purpose the advantages of climatic conditions (air temperature, relative humidity and wind speed).

This integrated technology combines two different processes: optimization of the solid/liquid separation, using a decanter, followed by the utilization of evaporation panels to eliminate the liquid fraction of the effluent, optimizing by this way the evaporation phenomenon, which is so important and resolute in certain cases, that it is absurd not to exploit it intensely.

The technology presented was followed by a research programme developed in the last three years, implemented in an agro-industrial unit located in a high polluted area of Portugal, with the aim to evaluate its efficiency and optimize the performance parameters. The conclusions of this research programme emphasized the importance of the evaporation phenomenon as a simple solution to deal with complex environmental problems.
Application of downflow floating medium flocculator/prefilter (DFF) - coarse sand filter (CSF) in nutrient removal
Authors: Ngo H. H. , Vigneswaran S.
Published: May 2018

In this study, the applicability and the advantages of the downflow floating medium filter (DFF) in wastewater treatment were examined. The experimental results indicated that the DFF with in-line flocculation addition is a good pretreatment unit to reduce phosphorus load (up to 80-89% removal). The DFF also resulted in uniform filterable-flocs of 32-42 µm throughout the filter run. Thus it can also successfully be used as a flocculator. The backwashing of floating medium was achieved with a small quantity of water and at low backwash velocity. The introduction of floating medium filter bed on top of a coarse sand filter unit (CSF) increased the filter run time and removal efficiency (more than 87 and 94% of NH3-N and T-P removal respectively), particularly at a low filtration rate (5 m3/m2.h).
Optimization of the performance of hoppered peripheral-feed clarifiers
Authors: Phiri Z. , Saito Y. , Ishak Bakri Bin , Harada H. , Nakajima S.
Published: May 2018

The tide of “development” gathering pace in developing countries has resulted in the production of increasing quantities of wastewaters. This inevitably necessitates a reappraisal/reassessment of wastewater technologies. This study demonstrates the role of simple physical modelling approaches in evaluating/appraising the technical performance of hoppered peripheral-feed (spiral-flow) clarifiers -- which clarifiers have enormous scope for use in small plants in developing countries. The study focuses on the optimization of local geometrics and hydrodynamics for the purposes of improving overall performance in hoppered spiral flow clarifiers. It is concluded that for a defined set of clarifier global geometry and loading conditions, an optimum race width and inlet nozzle diameter exist. The optimum values of these parameters for a defined conceptual prototype are presented. It is further concluded that the mere variation of either the race width or the inlet nozzle diameter significantly affects the hydraulic detention and solids removal interrelationships in hoppered spiral flow clarifiers. Under the conditions of this study, a 50% reduction in inlet nozzle diameter resulted in an incredible more than 50% loss in hydraulic efficiency. Overall, the possibility of significantly increasing clarifier capacity and/or overall performance by simply optimizing local geometrics and hydrodynamics has been demonstrated via a well tested and friendly methodology.
Effect of operating conditions on rejection of anionic pollutants in the water environment by nanofiltration especially in very low pressure range
Authors: Ratanatamskul C. , Yamamoto K. , Urase T. , Ohgaki S.
Published: May 2018

The recent development of new generation LPRO or nanofiltration membranes have received attraction for application in the field of wastewater and water treatment through an increasingly stringent regulation for drinking purpose and water reclamation. In this research, the application on treatment of anionic pollutants (nitrate, nitrite, phosphate, sulfate and chloride ions) have been investigated as functions of transmembrane pressure, crossflow velocity and temperature under very much lower pressure operation range (0.49 to 0.03 MPa) than any other previous research used to do. Negative rejection was also observed under very much low range of operating pressure in the case of membrane type NTR-7250. Moreover, the extended Nernst-Planck model was used for analysis of the experimental data of the rejection of nitrate, nitrite and chloride ions in single solution by considering effective charged density of the membranes.
Microfiltration of oxidation pond effluent using single flexible tubular fabric membrane and polyelectrolyte dosage
Authors: Megat Johari M. M. N. , Jusoh A. , Ghazali A. H. , Ahmadun F. R.
Published: May 2018

Membrane separation is an effective wastewater treatment alternative. However, as with all membrane processes, the fouling effect has always been one of the major limiting factors for their usage. Of the current available membrane modules, the tubular configuration is the least affected with fouling because of the relatively large passage. A novel approach of using tubular woven fabric membranes, naturally cheaper to produce, has been studied in treating secondary oxidation pond effluent. The membrane was prepared by sewing two strips of fabric, on both sides. Its tubular configuration is obtained by the flow of aqueous solution through, at an appropriate pressure and flow rate. Thus, there is no need for housing, as with most available tubular membranes in the market. Its flexible character also facilitates external mechanical cleansing. The fabric has pore sizes ranging between 20 and 40 μm. The effects of batch dosing the secondary pond effluent with Nalco Ultrion 8109W polyelectrolytes, with the main objective of improving filtrate flux, was investigated. The batch polyelectrolyte pretreatment, at three times the optimal dosage of floc jar test, showed a tremendous increase (five fold) on filtrate pseudo-steady-state flux. The pseudo-steady-state flux was 70 l/m2.h at 0.65 ml/l dosage.
Sediments flushing experiment in a trunk sewer
Authors: Sakakibara Takashi
Published: May 2018

Four series of sediments flushing experiment were carried out in a trunk sewer. The objectives of the experimental study is to survey the physical and chemical characteristics of sediments and estimate the effect of flushing. The flow rate of flushing were in the range of 0.40-0.44 m3/s. Tractive force at the flat portion of trunk sewer was calculated 0.3 N/m2 thus the critical particle size was predicted as 0.36 mm. However the decrease of sediments height was only 1 mm, and no difference of particle size distribution between before and after flushing. Sediments consisted of inorganic and organic substances. For organic substances the specific gravity was 2.50, water content was 73%, ignition loss was 39%. For inorganic substances, specific gravity was 2.60, water content was 20%, ignition loss was 1%. Sulfide concentration suggested no serious problem about odor and corrosion. The flushed load were in the range of 57-401 kg for BOD and in the range of 108-2,960 kg for suspended solids. The concentration of flushing water showed in the range of 100-640 mg/s as suspended solids. Estimation predicted 1-30% of total deposited load in the trunk sewer can be removed by one flushing event. The ratio of reduced load out of total discharged load is estimated as 4%.
Valuing environmental benefits from river quality improvements
Authors: Tyson J. M. , Foster V.
Published: May 2018

A deficiency in current approaches to meeting environmental expectations is the lack of a sound, consistent methodology by which the environmental benefit may be quantified in economic terms thereby enabling cost benefit/cost ratios to be determined and included in the decision making process. This is being addressed in the UK through a programme of collaborative research involving the Dept of the Environment, the Water Services Association and the environmental and economic regulators. An Interim Benefit Assessment Manual has been produced and is being evaluated by case studies, reporting in 1995 with a revised version of the Manual planned to be available in 1996.
Removal of nitrogen from coal gasification and coke plant wastewaters in A/O submerged biofilm-activated sludge (SBF-AS) hybrid system
Authors: Junxin Liu , Baozhen Wang , Weiguang Li , Chengji Jin , Xiangdong Cao , Lin Wang
Published: May 2018

Experimental research involving both laboratory and full-scale studies has been carried out to evaluate the nitrification-denitrification process carried out in a submerged biofilm (in anoxic zone)-activated sludge (in oxic zone) (SBF-AS) hybrid system for nitrogen removal from coal gasification and coke plant wastewaters. The anoxic reactor in the system was packed with fibrous carriers fixed on plastic plates of circular form for the attached growth of submerged biofilm with facultative denitrifying bacteria as dominant species to carry out denitrification, and the activated sludge process was used in the aerobic reactor for nitrification. As the denitrifying and nitrifying bacteria live under anoxic and aerobic conditions respectively in the hybrid system, the process was tested under the conditions of high organic and ammonia loading rates and short hydraulic retention time(HRT). The experimental results show that ammonia nitrogen, NH3-N removal is between 94% and 99.9% and COD removal between 80% and 95%.
Abiotic reduction of 2,4-dinitrotoluene in the presence of sulfide minerals under anoxic conditions
Authors: Jiayang Cheng , Suidan Makram T. , Venosa Albert D.
Published: May 2018

Abiotic reduction of 2,4-dinitrotoluene (DNT) in the presence of sulfide minerals has been investigated under anoxic conditions at 35°C. 2,4-DNT was abiotically reduced to 4-amino-2-nitrotoluene (4-A-2-NT) and 2-amino-4-nitrotoluene (2-A-4-NT) in the presence of high concentration of sulfide (0.84 mM). No abiotic reduction of 2,4-DNT was observed in the presence of low sulfide concentration (0.42 mM). The rate and the extent of the abiotic reduction of 2,4-DNT were increased with an increase in sulfide concentration. Sulfide served as an electron donor for the reduction of 2,4-DNT. The 2-nitro group was preferentially reduced, making the 2-A-4-NT:4-A-2-NT ratio in the final products 2:1. The addition of iron, nickel, and cobalt minerals significantly enhanced the abiotic reduction. The FeS, NiS, and CoS solids formed in the serum bottles catalyzed the reduction of 2,4-DNT preferentially to 4-A-2-NT. MnS and CuS solids also catalyzed the reduction of 2,4-DNT to 4-A-2-NT, but did not change the overall reduction of 2,4-DNT. However, the presence of calcium, zinc, and magnesium minerals impeded 2,4-DNT reduction. The calcium, zinc, and magnesium ions have a high affinity to sulfide, inactivating sulfide as an electron donor for the chemical reduction of 2,4-DNT.
Waste minimization and nitrocellulose fines removal at an ammunition plant
Authors: Fullington Barney G. , Park Jim K. , Kim Byung J.
Published: May 2018

The Radford Army Ammunition Plant (RAAP) produces nitrocellulose (NC) as a major ingredient in tank and artillery ammunition propellant. Through the process of NC production, wastewater is generated which contains large quantities of NC in the micron and sub-micron size range. These suspended and colloidal particles are collectively called NC fines. Under the impetus of a proposed Ammunition Procurement and Supply Agency suspended solids effluent limit of 25 mg/l and a greater emphasis on pollution prevention, significant research has been conducted into the areas of waste minimization and NC fine removal at the RAAP. One aspect of the current research involved a field study at the RAAP. The purpose of the field study was to inspect and discuss the entire NC production process with the operators, foremen, and NC production supervisor. With the information collected at the RAAP, it was possible to propose several waste minimization schemes and NC fines removal alternatives. From existing data, it was calculated that the proposed pollution prevention ideas could save the RAAP approximately $1,500,000 annually.
Pilot-scale neutralisation of underground mine water
Authors: Maree J. P. , van Tonder G. J. , Millard P. , Erasmus T. C.
Published: May 2018

Traditionally acid mine water is neutralised with lime (Ca(OH)2). Limestone (CaCO3) is a cheaper alternative for such applications. This paper describes an investigation aimed at demonstrating that underground mine water can be neutralised with limestone in a fluidised-bed. The contact time required between the limestone and the acid water, chemical composition of water before and after treatment, and economic feasibility of the fluidised bed neutralisation process are determined. A pilot plant with a capacity of 10k1/h was operated continuously underground in a gold mine. The underground water could be neutralised effectively using the limestone process. The pH of the water was increased from less than 3 to more than 7, the alkalinity of the treated water was greater than 120 mg/l (as CaCO3) and the contact time required between mine water and limestone was less than 10 min (the exact contact time depends on the limestone surface area). Chemical savings of 56.4% can be achieved compared to neutralisation with lime.
Decentralisation of the Emscher sewerage system - expansion of the Emscher mouth treatment plant
Authors: Teichgräber Burkhard , Hermanns Ulrich
Published: May 2018

Since the beginning of the 20th Century, the Emscher and its tributaries have been operated as open waste water courses (Emscher System). Between 1966 and 1977, the Emscher Mouth Treatment Plant was constructed for the biological treatment of domestic and industrial discharge from the 774 square kilometre Emscher catchment area. The plant was designed for 5 million population equivalents. Since the beginning of the Nineties, the Waste Water Management Regulations require, apart from the elimination of carbon, also the elimination of nitrogen and phosphorus, in order to reduce, as far as possible, the load on natural, flowing bodies of water and to protect the North Sea. While the COD values are observed with a narrow margin, the nitrogen values make it necessary to expand the aeration volume of the Emscher Mouth Treatment Plant by 50% to 216,000 m3. For this purpose, comprehensive studies, as well as pilot studies on the subject of filtration, have been carried out. Construction of the new aeration tanks was begun in spring 1993. The expansion will be completed at the end of 1996. Investments totalling 102 million DM are required.
Analysis of water pollution and evaluation of purification measures in an urban river basin
Authors: Hosoi Y. , Kido Y. , Nagira H. , Yoshida H. , Bouda Y.
Published: May 2018

The inflow of pollutant load from urban areas and the stagnation of water due to sea water intrusion cause the deterioration of river water quality in tidal zone. In order to improve water quality, various measures such as the reduction of pollutant load by sewage systems, discharge control from sewage treatment plants considering river flow, nutrient removal by aquatic plants, and the dredging of bottom sediments have been examined. The choice of these measures depends on the situation of the river environment and finances. In this study, a field survey was carried out in a typical urban river basin, first. Secondly, on the basis of this survey, a mathematical model was formed to simulate flow and water quality. Several purification alternatives designed for the investigated river basin were comparatively evaluated from the viewpoint of the effect of water quality improvement and their cost. Finally, they were prioritized. Through this case study, a planning process of river water quality management was shown.
Process selection, design and operation of the EDE WWTP
Authors: Leeuw E. J. , van't Oever E.
Published: May 2018

According to European agreements, many WWTPs (waste water treatment plants) have to be modified and extended to reach stricter effluent standards with regard to phosphorus and nitrogen. This paper presents the modification of a 300,000 p.e. WWTP. The following steps are distinguished: location/centralization study, process pre-selection, pilot tests and process control.

Most important aspects in the location study are costs and ecological importance of the receiving water. In the process pre-selection study two nitrogen and phosphorus removal processes were selected: a high cost/low risk process and a low cost/high risk process. Final selection of the Bio-Denipho process was based on comparison of both processes in pilot tests. During the six months operation period the process control programs for weekdays/weekends, day hours/night hours, dry weather flows/storm weather flows resulted in low nitrogen concentrations in the effluent.
Adaption of the main waste water treatment plant in Vienna to meet Austrian emission regulations
Authors: Kainz Harald , Hofstetter Herbert
Published: May 2018

The modification of the main waste water treatment plant in Vienna will take place in accordance with the minimum efficiences laid down in the emission regulations as issued in 1991 by the Austrian Federal Office for Agriculture and Forestry. To meet these figures it is necessary to adapt the plant by 2001. The studies on several variants and the evaluation process showed a 2-step technology with partial by-passing of the 1st step to be the optimal solution. For this flexible system a new aeration tank volume of only 210,000 m3 is sufficient. Test-runs with a semi-commercial plant confirmed the correctness of all calculations. Possibilities for further modifications have been considered, e.g. dimensioning of all relevant hydraulic installations up to 24 m3/sec, final purification by sand or flocculant filtration and spare areas for measures after 2015.
Upgrading a large wastewater treatment plant with the help of a large-scale pilot plant
Authors: Bendzuck Chris G.
Published: May 2018

A large scale pilot plant was designed and built and was run over several months in order to collect data and experiences for the final design of a 400.000 P.E. waste water treatment plant. The design and building of this pilot plant is explained with respect to the two objectives examination of plant performance and comparison of different treatment types. In two examples, concerning the influence of temperature and hydraulic balance on EBPR (Enhanced Biological Phosphorus Removal) process the results and their influence on the final design are described. Compared with a design according to the standard design rules in Germany (ATV-A131, 1991), the future large WWTP can meet the effluent requirements with 30% less volume. The costs for the pilot plant were less than 35% of the costs saved by the now possible reduction of tank volume.
Thermal hydrolysate as a carbon source for denitrification
Authors: Barlindhaug John , Ødegaard Hallvard
Published: May 2018

Thermal hydrolysate is the liquid fraction (supernatant) of thermally treated wastewater sludge. The objective of the present study was to investigate the quality of thermal hydrolysate as a carbon source for denitrification. Steady state denitrification experiments in moving bed biofilm reactors were carried out. It was demonstrated that 2/3 of the COD in the thermal hydrolysate was utilised as a carbon source in the post denitrification step, with a retention time of 52 minutes. This degree of utilisation is about the same as reported for biological hydrolysate, which generally has been considered to be of better quality as a carbon source than thermal hydrolysate. The yield of soluble COD in the thermal hydrolysis process (180°C in 30 minutes) was found to be 28%. Typical COD-yields for biological hydrolysis are around 11%.
Water quality models: Typologies for environmental impact assessment
Authors: Varis Olli
Published: May 2018

Much of the practical use of water quality models is related to Environmental Impact Assessment (EIA). There is a boom of released EIA guidelines from various institutions, typically with little reference to specific methodologies. This paper presents a discussion on the applicability of various water quality modelling approaches for use in different phases of an EIA protocol. The criteria used include the project cycle process, decision types, scales of impact and paradigms and cognitive styles of problem solving. Illustration is given with a selection of approaches used in a range of natural, socio-economic and institutional settings.
Possibilities for increased nutrient removal with a final filtration stage
Authors: Rothman M. , Hultgren J.
Published: May 2018

Bromma sewage treatment plant (STP) is one of three plants in Stockholm. To meet more stringent requirements for nutrient removal the plant has been extended with a final filtration stage. Earlier it has not been possible to operate the plant with nitrification during winter time. Bad settling properties of the activated sludge have led to bulking sludge and high concentrations of BOD and phosphorus in the effluent. With the filter stage it is now possible to reduce the load on the biological stage by by-passing part of the flow directly to the filters. The result has been very promising and it seems that the plant can meet the new demands for nitrogen removal without extension of the aerated volumes.