bluuebunny/crossref_metadata_2025 huggingface dataset:
Enterococci in the New Zealand environment: implications for water quality monitoring
Authors: Anderson S. A. , Turner S. J. , Lewis G. D.
Published: May 2018

Faecal enterococci ecology outside the host is of great relevance when using these organisms as indicators of water quality. As a complement to New Zealand epidemiological studies of bathing water quality and health risk, a study of the environmental occurrence of these organisms has been undertaken. Specific concerns over the use of enterococci derive from the unique situation in New Zealand which has few chlorinated sewage effluents, a high ratio of grazing animals to humans, and significant inputs of animal processing effluents into the environment. Human and animal faecal wastes are the main sources, with 106–107cfu/100ml found in human sewage. Analysis of domestic and feral animal faeces found enterococci in the range of 101–106cfu/g with considerable variation between species. The latter observations support the notion that a considerable proportion of the load in urban/rural catchments and waterways (typically 102–103 enterococci cfu/100ml) is derived from non-human sources. Previous studies of enterococci quiescence in marine/fresh waters indicate that they enter a non-growth phase, exposure to sunlight markedly reducing culturability on selective and non-selective media. Enterococci were also found to survive/multiply within specific non-faecal environments. Enterococci on degrading drift seaweed at recreational beaches exceeded seawater levels by 2–4 orders of magnitude, suggesting that expansion had occurred in this permissive environment with resultant potential to contaminate adjacent sand and water. These studies suggest that multiple sources, environmental persistence, and environmental expansion of enterococci within selected niches add considerable complexity to the interpretation of water quality data.
Evaluation of escherichia coli as the main indicator of faecal pollution
Authors: Baudišová D.
Published: May 2018

The paper presented supports E. coli assessment as a major indicator of faecal pollution. Its assessment brings advantages when compared with assessment of total coliforms and faecal coliforms because (a) E. coli survives in river water for shorter period than other coliforms and faecal coliforms and (b) its occurrence in a stream (in an area without any significant point sources of pollution), in particular when compared with total coliforms, is more stable. Significant differences appear especially in the summer period when the elevated temperature allows development of non-faecal bacteria.
Evaluation of a procedure for detection of viable giardia cysts in wastewater sludge
Authors: Thiriat L. , Bigot V. , Schwartzbrod J.
Published: May 2018

The goal of this work was to quantify the effectiveness of wastewater treatment systems in removing Giardia cysts. For this, the quantity and the viability of the cysts recovered from primary and digested sludge were studied. The digestion treatment has no effect on the number of cysts recovered, however it affects their viability.
The presence of Giardia and Cryptosporidium in surface waters and effluents in Israel
Authors: Zuckerman U. , Gold D. , Shelef G. , Armon R.
Published: May 2018

During a period of 9 months (May 1995-January 1996), various environmental sources were investigated for the presence of Giardia and Cryptosporidium in Israel. Out of 15 samples from five streams, 12 were positive for Cryptosporidium (80%) with an average concentration of 0.04–1.9 oocysts/l and 8 were positive for Giardia (53.3%) with 0.05–0.78 cysts/l. Two springs were also tested and found positive for Cryptosporidium and (0.54 oocysts/l) only. The main drinking water reservoir of Israel, Lake Kineret, was also sampled 6 times at two sites. Cryptosporidium was isolated in 4/6 samples (66.6%) at an average concentration of 0.3–1.09 oocysts/l while Giardia was present in 5/6 samples (83.3%), 0.135–16.2 cysts/l. Drinking water entering a filtration pilot plant was also tested and found positive for Cryptosporidium in 23/35 samples (0–317 oocysts/l) and 8/35 for Giardia (0–16.7 cysts/l). In order to evaluate some potential inputs of contamination of the drinking water sources, two possible contributors were tested: domestic sewage and cowshed effluents. In sewage effluents, 3/3 samples were positive for both Cryptosporidium and Giardia. The oocysts and cysts were present at 8.3–8.05/l and 5–27.3/l respectively. In cowshed effluents, 1/6 samples was positive for Cryptosporidium at a high concentration (3,630 oocysts/l) but no Giardia cysts were found. The levels of Cryptosporidium and Giardia oocysts and cysts isolated from these environmental samples may present a public health hazard although no major outbreaks have so far been reported in Israel.
Occurrence of Cryptosporidium spp oocysts and Giardia spp cysts in sewage influents and effluents from treatment plants in England
Authors: Bukhari Z. , Smith H. V. , Sykes N. , Humphreys S. W. , Paton C. A. , Girdwood R. W. A. , Fricker C. R.
Published: May 2018

Cryptosporidium parvum and Giardia duodenalis can cause severe diarrhoea in infected individuals and their transmissive stages, oocysts and cysts, are voided in large numbers with the faeces of infected hosts. Contaminated sewage effluents are recognised as a potential source of waterborne (oo)cysts. In this investigation methods optimised for the recovery of both from a range of wastewaters were used to determine the occurrence of these organisms in influents, effluents and sludges from seven sewage treatment works in England. The data indicated the presence of small numbers of oocysts both in sewage influent and effluent samples whereas cysts were detected more frequently and at higher concentrations in both influents and effluents. Whilst sludge samples from 1/5 sites contained oocysts, cysts were detected from all five sites. These investigations indicate that discharge of sewage effluents into a watercourse, which may be used for potable water abstraction, can contaminate that watercourse with potentially infectious oocysts. In addition, the application of sludge to land can be responsible for contaminating watercourses with (oo)cysts following run-off or leaching.
Rapid detection of viable enteroviruses in water by tissue culture and semi-nested polymerase chain reaction
Authors: Murrin K. , Slade J.
Published: May 2018

A method has been developed for the detection of waterborne viruses which combines the speed of PCR techniques with the assurance of viability given by tissue culture. Environmental water samples are concentrated by adsorption/elution and protein precipitation, subjected to a brief period of culture and the tissue culture fluid assayed for the presence of viruses. RT-PCR was carried out with the EZ rTth DNA polymerase system. When applied to environmental samples results comparable to those obtained by traditional methods were obtained within 3 days of receipt of sample.
Microbiological conversions in nitrogen removal
Authors: Van Loosdrecht M. C. M. , Jetten M. S. M.
Published: May 2018

Nitrogen conversion processes are essential for most wastewater treatment systems. Due to the many possible conversions, and the complexity of analysing the reactions under actual conditions, there is much room for confusion. This review provides an overview of the possible microbiological nitrogen conversions described in literature. The relevance of these conversions with respect to wastewater treatment processes is discussed. Rates described for aerobic denitrification or denitrification by autotrophic nitrifiers are so low that these conversions probably do not play a significant role under practical conditions. Heterotrophic nitrification may be of relevance only when the wastewater contains a high COD/N ratio (>10). Anaerobic ammonium oxidation can occur in fully autotrophic systems with very long sludge retention times or biofilm systems. This conversion offers great opportunities since it allows us to denitrify with ammonium as electron donor, i.e. no organic substrate is needed in the nitrogen removal process.
Sulfur-based autotrophic denitrification pond systems for in-situ remediation of nitrate-contaminated surface water
Authors: Flere Joel M. , Zhang Tian C.
Published: May 2018

The feasibility of using the sulfur/limestone autotrophic denitrification (SLAD) process as an in-situ method for remediation of nitrate-contaminated surface water was investigated. Four bench-scale pond systems with working volumes of 21.4 litres each and hydraulic retention time (HRT) of 30 days were operated under either mixed conditions or unmixed conditions. Under mixed (aerobic) conditions, with the addition of alkalinity to raise pH, NO3−-N removal in the SLAD ponds were 85-100%, while the control reactor showed negative removal. Sulfate production under mixed conditions, due to the activities of non-denitrifying bacteria such as Thiobacillus thiooxidans, was between 1000-2500 mg/l SO42−, which makes the application of the SLAD ponds under aerobic conditions questionable. Under unmixed (anoxic) conditions, NO3−-N removal in the SLAD ponds decreased to 75-88%; sulfate production, however, also decreased by more than 50% due to the inhibition of the activity of non-denitrifying bacteria. Additional batch experiments indicated that sulfate production in the SLAD systems was acceptable under anoxic conditions. Therefore, the application of the SLAD ponds under unmixed (anoxic) conditions is feasible for in-situ remediation of nitrate-contaminated surface water.
Short SRT (solids retention time) nitrification process/flowsheet
Authors: Kos Peter
Published: May 2018

The short SRT nitrification process/flowsheet was developed to provide an inexpensive alternative for plants in the northern climates which need to upgrade their activated sludge process for year-round nitrification or nitrogen removal. In this process/flowsheet supplemental nitrifiers are added daily to the activated sludge process to replenish nitrifiers removed with the wasted activated sludge. The supplemental nitrifiers are grown in a separate small side-stream aeration tank using ammonia available in the digested sludge dewatering liquid or in the digester supernatant. Paper presents description of this flowsheet, the theoretical background and results of modeling. Modeling of this process/flowsheet showed that the addition of the supplemental nitrifiers allows the main stream activated sludge process to nitrify during low winter temperatures at very low SRT values. For example an SRT of 7 to 10 days at 10°C is required, instead of 13 to 18 days for conventional nitrification. Thus this process/flowsheet can provide nitrification in a substantially smaller aeration tank than required for the conventional nitrification.
Organic carbon biodegradability and heterotrophic bacteria along a combined sewer catchment during rain events
Authors: Seidl M. , Servais P. , Martaud M. , Gandouin C. , Mouchel J. M.
Published: May 2018

The aim of this study was the evaluation of fluxes of organic carbon and biodegradability of waste waters during rain events in order to better predict the impacts of combined sewer overflows (CSO). The combined sewer system studied was located in a densely populated urban catchment adjacent to Paris. Five subcatchments of different size, have been monitored during several rain events for suspended solids, conductivity, ammonium, chemical and biological oxygen demand. In addition, two of these subcatchments have been evaluated for dissolved and particulate organic carbon, their biodegradable fractions, and the total bacterial biomass. Several indexes, indicate a lower degradability of waste water during dry weather at the downstream stations, accompanied by an increase of bacterial size and bacterial biomass. A further decrease of biodegradable organic carbon related to rain intensity can be seen at all stations. Our results show a higher proportion of refractory organic carbon during rain events than during dry weather with a possible contribution of the in-sewer sediments to the bacterial wet weather flux.
Study on hydrogen sulfide generation rate in pressure mains
Authors: Kitagawa Mitsuo , Ochi Takatoshi , Tanaka Syuji
Published: May 2018

Experimental facilities comprising 1.8 km of pipeline, 100 mm in diameter and pumping equipment, were installed in a wastewater treatment plant and operated continuously for more than one year to clarify the main factors governing hydrogen sulfide generation in pressure mains. The effects of temperature, organic matter, and sulfate on sulfide generation rate were investigated based on observed values. The sulfide generation rate depended significantly on wastewater temperature. It was confirmed not empirically but experimentally that the effect of temperature (T) was expressed by (1.065)T-20. In respect of organic matter, it is considered that there is a little effect of organic matter concentration on sulfide generation rate when the fluctuation of soluble organic matter concentration is slight. However, based on observed values, it was found that sulfide generation rate clearly depended on sulfate concentration when the biofilm was rather thick like these experiments. Also, partial penetration of sulfate into biofilm was confirmed using a biofilm model. Furthermore, biofilm model as a sound method for predicting sulfide generation rate was discussed.
Sulfide production and wastewater quality in pressure mains
Authors: Nielsen Per Halkjær , Raunkjær Kamma , Hvitved-Jacobsen Thorkild
Published: May 2018

An empirical model for predicting sulfide production in pressure mains (Hvitved-Jacobsen et al., 1988) was evaluated and modified based on results obtained from two intercepting pressure mains located in the Northern part of Jutland, Denmark. Mass balances in pipe influent and effluent were made for volatile fatty acids, VFA (formate, acetate, propionate and butyrate), dissolved COD, DOC and sulfide and biofilm surface rate for sulfide and organic matter were calculated. Relatively high sulfide formation rates were observed at low temperatures (5-12°C). The sulfide production rate strongly depended on wastewater quality in terms of VFA and dissolved carbohydrate concentration. Based on these two sets of observations - wastewater quality and temperature - the original empirical model was modified.
Effect of continuous addition of an organic substrate to the anoxic phase on biological phosphorus removal
Authors: Meinhold J. , Pedersen H. , Arnold E. , Isaacs S. , Henze M.
Published: May 2018

The continuous introduction of a biological phosphorus removal (BPR) promoting organic substrate to the denitrifying reactor of a BPR process is examined through a series of batch experiments using acetate as model organic substrate. Several observations are made regarding the influence of substrate availability on PHA storage/utilization and phosphate uptake/release. Under anoxic conditions PHB is utilized and phosphate is taken up, indicating that at least a fraction of the PAO can denitrify. The rates of anoxic P-uptake, PHB utilization and denitrification are found to increase with increasing initial PHB level. At low acetate addition rates the P-uptake and PHB utilization rates are reduced compared to when no acetate is available. At higher acetate addition rates a net P-release occurs and PHB is accumulated. For certain intermediate acetate addition rates the PHB level can increase while a net P-release occurs. Whether the introduction of BPR promoting organic substrates to the denitrifying reactor is detrimental to overall P-removal appears to be dependent on the interaction between aerobic P-uptake, which is a function of PHB level, and the aerobic residence time.
Suspended sediment transport in rigid boundary channels at limit deposition
Authors: Nalluri Chandramouli , Spaliviero Fabio
Published: May 2018

Sedimentation or deposition of sediments is a crucial economical and technical problem for the design of conveyances carrying sediment laden flow such as sewers, irrigation canals and, in general, rigid boundary channels. In light of investigations on sediment transport at the limit of deposition carried out during the last two decades at the University of Newcastle upon Tyne, experimental data on suspended sediment transport collected by Pulliah (1978), Macke (1982) and Arora (1983) are analysed. The data cover a wide range of volumetric concentrations (3.7 to 48542 ppm) and sediment size (0.006 to 0.37 mm). A new model for the prediction of suspended sediment transport in rigid boundary channels at limit deposit is proposed. The model was fitted by multiple regression analysis to Macke's (1982) and Arora's (1983) experimental data. Pulliah's (1978) data validate the relation. Nalluri et al. (1994) bed load friction model is checked with available data and a good agreement is observed.
Sediment transport under dry weather conditions in a small sewer system
Authors: Schlütter Flemming , Schaarup-Jensen Kjeld
Published: May 2018

Increased knowledge of the processes which govern the transport of solids in sewers is necessary in order to develop more reliable and applicable sediment transport models for sewer systems. Proper validation of these are essential. For that purpose thorough field measurements are imperative. This paper renders initial results obtained in an ongoing case study of a Danish combined sewer system in Frejlev, a small town southwest of Aalborg, Denmark. Field data are presented concerning estimation of the sediment transport during dry weather. Finally, considerations on how to approach numerical modelling is made based on numerical simulations using MOUSE TRAP (DHI 1993).
Solids transport by flushing of combined sewers
Authors: Ristenpart Erik
Published: May 2018

For several reasons field observations of solids transport processes in combined sewage flows are very problematic. To avoid some of these difficulties a case study in a real sewer under controlled conditions was carried out to examine solids movement at high flow rates by means of flushing experiments. The investigations illustrate the complexity of solids transport. Corresponding behaviour of the bed deposits and the suspended solids was recognized. An abrupt increase of the SS load was caused entirely by volatile solids. Additional factors influencing the transport processes, such as the prehistory of the event are demonstrated. With regard to the question if the procedure of flush cleaning may be used as an alternative measure to the cost intensive high pressure jetting it has to be stressed that complete cleaning of sewer lengths with sediment beds cannot be expected by flushing. However, keeping sewers clean over prolonged periods by regular flushing may be an economic way of sewer operation.
Factors affecting nitrogen removal from domestic wastewater using immobilized bacteria
Authors: Aravinthan Vasanthadevi , Takizawa Satoshi , Fujita Kenji , Komatsu Kazuya
Published: May 2018

The parameters affecting the nitrogen removal process by the immobilized bacteria in the anoxic-oxic process have been studied by investigating two bench scale Runs A and B. The hollow polypropylene pellets have been dosed into the anoxic reactor in Run A and into the oxic reactors of both Runs up to 24% of volume. Run B was operated with no pellets in the anoxic reactor as a control. The maximum nitrification rate of 0.4 kg NH4-N/m3d was achieved in sufficient DO (6.5 mg/l) at 15°C in the reactor with both activated sludge and immobilized micro-organisms. The volumetric nitrification rate was found to be greatly dependent on bulk oxygen concentration especially when the DO was maintained below 4 mg/l. A mathematical model developed successfully simulated the experimental results showing the variation of nitrification rate with DO. In the case of denitrification, the contribution of immobilized bacteria was prominent when lesser concentration of MLSS was present in the activated sludge in the combined immobilized and activated sludge system. The presence of immobilized bacteria in the anoxic reactor will be effective when higher nitrate nitrogen loadings are expected and the maintenance of higher MLSS than 2 g/l in an activated sludge facility is not feasible.
A Danish sewer research and monitoring station
Authors: Schaarup-Jensen Kjeld , Hvitved-Jacobsen Thorkild , Jütte Bent , Nielsen Bjarne , Pedersen Tage
Published: May 2018

A research and monitoring station has been established as a part of the intercepting sewer from Frejlev, a small town of 2000 inhabitants 7 km Southwest of Aalborg, Denmark. The purpose is to perform continuous high quality time series of flow as well as waste water and runoff water characteristics. Based on these future time series, research will be carried out in order to establish knowledge on dry weather characteristics, and rainfall-runoff relationships including the variability of relevant storm water pollutants. Furthermore, the measurements can form the basis of a better understanding of transport and transformation of pollutants in combined sewers including suspended and bed load characteristics, sedimentation and resuspension.
A unified basis for the design of nitrogen removal activated sludge process - the Braunschweig exercise
Authors: Orhon D. , Hanhan O. , Görgün E. , Sözen S.
Published: May 2018

In this study a unified approach is defined for the design of single sludge pre-denitrification systems, based upon recently developed multi-component modelling of activated sludge. The “Braunschweig exercise” is adopted as a reference point, mainly for the critical review of different design methods proposed. Emphasis is placed upon the significance of process stoichiometry when using different parameters for substrate and biomass. Relationships proposed for the assessment of excess sludge production and oxygen requirements are evaluated in comparison with the unified approach. A new design methodology is defined and numerically tested with the basic data generated for the Braunschweig exercise.
The performance of a novel combined sewer overflow with perforated conical screen
Authors: Jefferies C. , Allinson C. L. , McKeown J.
Published: May 2018

Increasing concern over the discharge of sewer solids from combined sewer overflows (CSOs) has encouraged the introduction of installations which incorporate either mesh or bar screen arrangements, or both. Gross solids create visual and aesthetic pollution if they reach watercourses. An entirely new arrangement for a CSO with a perforated screen of 6 mm diameter apertures is described in the paper. The arrangement is circular, with tangential flow across the screen to facilitate its cleaning. High velocities across the screen holes ensure that solids which have been prevented from discharging are swept clear from the screen. As a result, a sufficient screen area remains free from trapped solids to permit discharge of flow. The device has been designed to meet all anticipated performance criteria for the removal of solids, and to require a minimum of maintenance.

A thorough testing programme in different conditions is described. Laboratory testing utilised a wide range of gross solids and flows to determine efficiencies of solids removal under all anticipated operating conditions. The performance of the CSO in a sewer environment was evaluated at a sewage treatment works with flows up to 1801/s using both raw and treated sewage to simulate storm sewage of different strengths. Both the device and its testing are described, together with the results of the testing programme.
Products from primary sludge fermentation and their suitability for nutrient removal
Authors: Moser-Engeler R. , Udert K. M. , Wild D. , Siegrist H.
Published: May 2018

Both denitrification and biological phosphorus removal depend on the presence of readily biodegradable carbon. Primary sludge fermentation is one way of producing such substrates. Soluble products of sludge fermentation are mainly short-chain fatty acids with two to five carbon atoms (84% of dissolved COD). In considering molar degradation rates by denitrifying organisms in batch experiments, the acids can be divided into two groups: the preferentially degraded linear forms of C2 to C5 acids and the branched C4 and C5 acids. The non-identified fraction (16% COD) which might contain acids with more than five carbon atoms is also removed by the activated sludge either by degradation or adsorption. In batch experiments with anaerobic and aerobic cycles, the uptake rate for short-chain fatty acids by phosphorus accumulating organisms and the ratio of phosphorus release to substrate uptake are determined. Acetate and propionate are taken up much faster than the C4 and C5 acids, which show very similar rates. For the ratio of phosphorus release to substrate uptake the situation is more complicated. The acids with four carbon atoms show by far the highest values.
Effect of addition of anaerobic fermented OFMSW (organic fraction of municipal solid waste) on biological nutrient removal (BNR) process: preliminary results
Authors: Pavan P. , Battistoni P. , Traverso P. , Musacco A. , Cecchi F.
Published: May 2018

The paper presents results coming from experiments on pilot scale plants about the possibility to integrate the organic waste and wastewater treatment cycles, using the light organic fraction produced via anaerobic fermentation of OFMSW as RBCOD source for BNR processes. The effluent from the anaerobic fermentation process, with an average content of 20 g/l of VFA+ lactic acid was added to wastewater to be treated in order to increase RBCOD content of about 60-70 mg/l. The results obtained in the BNR process through the addition of the effluent from the fermentation unit are presented. Significant increase of denitrification rate was obtained: 0.06 KgN-NO3/KgVSS d were denitrified in the best operative conditions studied. -Vmax shows values close to those typical of the pure methanol addition (about 0.3 KgN-NO3/KgVSS d). A considerable P release (35%) was observed in the anaerobic step of the BNR process, even if not yet a completely developed P removal process.
Developments in sludge characterisation in Europe
Authors: Leschber Reimar , Spinosa Ludovico
Published: May 2018

The need for a regular and environmentally safe utilisation and disposal of sludges of different origins is well recognised by the EU countries. A number of requirements, such as guide and/or limit values, are contained in the European Directives dealing with this subject, but methods for determination of the respective parameters are often not described, so there is an urgent need to close these gaps. For this reason, CEN (European Committee for Standardisation) has established the Technical Committee 308 (TC308) whose scope is the (i) standardisation of methods employed for sludge characterisation and (ii) drafting of guidelines for good practice in the production, utilisation and disposal of sludges. At present, some physical and chemical parameters have been standardised, a sludge terminology has been set up and a guide for agricultural use of sludge already finished. Future work will concentrate upon determination of nutrients necessary for agricultural use, physical properties, to improve sludge handling, and an inventory of sewage and waterworks sludges, to open new ways of utilisation.
A treatability index for reservoir water
Authors: Ta C. T. , Woodward C. A.
Published: May 2018

A Treatability Index is developed to allow comparison of different reservoir waters according to their effects on a water treatments works. For the water treatment works which employs rapid gravity filters, the index is the product of the algal concentration, the clarification coefficients of algae and the filtration rate.

The index is applied to reservoir waters within Thames Water area. Algae observed in reservoirs are grouped according to their shapes. Among these groups, twenty frequently observed species were selected and their clarification coefficients were measured. The treatability index was then evaluated for different waters and at different times of the year. The results were correlated to the filter run lengths and the development of headloss across the filters.
Effect of inoculation of iron oxidizing bacteria on elution of copper from anaerobically digested sewage sludge
Authors: Ito Ayumi , Umita Teruyuki , Aizawa Jiro , Kitada Kumiko
Published: May 2018

The effect of inoculation of iron oxidizing bacteria on elution of Cu from anaerobically digested sewage sludge was investigated without adding ferrous sulfate as a substrate. The inoculation of iron oxidizing bacteria to the sludge brought about the effective elution of Cu at pH 2 and 3. Ferric ion produced by the biological oxidation of ferrous ion which was eluted from the sludge or ferric ion eluted directly from the sludge and iron oxidizing bacteria caused the elution of Cu. Furthermore, both chemical and biological leachings of Cu from CuS were studied at pH 2, 3 and 4. It was found that both ferric ion and iron oxidizing bacteria could elute Cu. The elution rate of Cu with ferric ion decreased as the pH increased and two moles of Fe(III) eluted 1 mole of Cu. The biological leaching by iron oxidizing bacteria eluted Cu more effectively than the chemical one with sulfuric acid or ferric sulfate at pH 2, 3 and 4.
Characterization of biogenic organic matter (BOM)
Authors: Frimmel Fritz H. , Jahnel Jutta , Hesse Sebastian
Published: May 2018

Biogenic organic matter (BOM) is of ubiquitous relevance in all aquatic systems. This is due to the fundamental function of the natural organic matter in combination with the microbial activity which guarantees the degradation in and the self purification of water in the hydrological cycle. In addition, the refractory part of the widely distributed BOM acts as effective adsorbent for most water constituents, and in case of mobile fractions as active vehicle for pollutants. In contrast to the broad importance of the occurrence and role of BOM, there is a fairly small variety for its analytical characterization. Especially in the field of in-situ measurements and of the determination in the original concentration range of aqueous samples, relatively little data have been collected. This is partly due to the complex structure of BOM, partly to the limited availability of analytical methods suited for that type of investigations.

The aim of the paper is to give typical examples for the a) physical/chemical, b) microbiological and c) technologically orientated methods of the analytical characterization of BOM in aqueous solution and to draw conclusions on the function of BOM in aquatic systems and their use for man.
Influence of alkalinity on the hydraulic conductivity of bentonite-sand liners
Authors: Wareham David G. , Farajollahi Arman , Milke Mark W.
Published: May 2018

The aim of this research is to record the impact of specific changes in the molding water alkalinity on the hydraulic conductivity of a compacted bentonite-sand mixture. Adding alkalinity to the molding water influences the charge density existing on the clay particles. This can increase the amount of separation of the bentonite particles which causes a decrease in the hydraulic conductivity of the compacted mixture. At the optimum alkalinity the mixture possesses the smallest hydraulic conductivity. In this research an optimum alkalinity (pH=10.1) for a compacted bentonite-sand mixture (7.5% bentonite) was derived from the liquid limit test and the falling-head permeability test.
Effects of leachate recycle and anaerobic digester sludge recycle on the methane production from solid wastes
Authors: Bae J. H. , Cho K. W. , Lee S. J. , Bum B. S. , Yoon B. H.
Published: May 2018

Performances of lab-scale lysimeters were evaluated to develop a new landfill system for the recovery of CH4 from solid wastes. Lysimeters were operated at three different conditions: control (L-control), leachate recycle (L-recycle), and sludge recycle (L-sludge). For L-sludge, sludge from the leachate-treating anaerobic digester was recycled, whereas the produced leachate was recycled for L-recycle. After 430 days of operation, the amounts of COD recovered by CH4 were 0.13, 0.29, and 22.5 kg for L-control, L-recycle, and L-sludge, respectively. For L-sludge, 77% of total COD outflow was recovered by CH4, and the remaining COD was washed out by leachate. However, less than 5% of total COD outflow was recovered as CH4 from L-control and L-recycle. Stabilization of organics in L-sludge approached completion within 430 days, while other lysimeters still produced leachate with high COD. Results indicated that the continuous addition of active methanogenic population from the anaerobic digester rather than simple leachate recycle was effective for the rapid and significant CH4 recovery from solid wastes.
Bubble dynamics and oxygen transfer in a hypolimnetic aerator
Authors: Burris Vickie L. , Little John C.
Published: May 2018

A hypolimnetic aerator operating in one of the City of Norfolk's water supply reservoirs was tested. Dissolved oxygen (DO) profiles, water flow rate, and gas-phase holdup were measured over a wide range of applied air flow rates. A model that was developed to predict oxygen transfer in a Speece Cone was modified to conform to the conditions of the hypolimnetic aerator. By varying a single parameter (the initial bubble size) the model was found to provide a close fit to the experimental DO profiles as well as the observed gas-phase holdup. The model was used to show that a doubling in oxygen transfer may be achieved if initial bubble size is reduced from 5 mm to 2.5 mm. Knowing the initial bubble size, it should be possible to predict water velocity by incorporating the effect of momentum. Further work is now underway to test this approach and to examine the possibility of extending this generalized model to cover the range of hypolimnetic aeration and oxygenation devices.
The importance of pre-reservoirs for the control of eutrophication of reservoirs
Authors: Pütz Klaus , Benndorf Jürgen
Published: May 2018

Pre-reservoirs are small reservoirs, with a water-retention time of a few days, that reduce the phosphorus input in main reservoirs. The process of phosphorus removal involves the biochemical conversion from the dissolved to the particulate form (mainly phytoplankton) and the sedimentation of this particulate matter. The input variables are light, orthophosphate concentration, temperature of the inflowing water and discharge. The phytoplankton activity plays the most important role among the various processes. The maximization of orthophosphate elimination depends on adequate design, construction and operation of pre-reservoirs. A simple calculation procedure for the removal rates of orthophosphate-P has been developed. The efficiency of pre-reservoirs is limited, because the light intensity and the temperature during the winter period are low; on the other hand, discharge is often high in March and April (snowmelt). Although pre-reservoirs are an important tool for reservoir water-quality management, but they cannot substitute remedial action in the catchment area.
Nutrient release from inundated land of a tropical reservoir (nanhua reservoir, Taiwan)
Authors: Chang Shui-Ping , Wen Ching-Gung
Published: May 2018

Nutrient release from land inundated by creation of a tropical reservoir (Nanhua Reservoir, Taiwan) is investigated. Both the magnitudes of nitrogen and phosphorus which might be released from inundated land are determined on the basis of measurements of biomass and nutrients content of terrestrial vegetation and the nutrients content of topsoil. The fresh biomass of the terrestrial vegetation was estimated at 48600 kg/ha, with an equivalent dry biomass of 15500 kg/ha. After complete decay following submergence, the terrestrial vegetation could potentially contribute 242 kg of nitrogen and 37 kg of phosphorus per hectare. The kinetics of nutrient release from topsoil is determined on a laboratory scale for 80 days, which showed that the phosphorus release rate is averaged at 5.25 mg TP/m2/day in anaerobic conditions and 1.34 mg TP/m2/day in aerobic conditions, also the nitrogen release rate is averaged at 78.31 mg TKN/m2/day in anaerobic condition and 35.71 mg TKN/m2/day in aerobic conditions. Based on the actual operation status of Nanhua Reservoir during the initial operation period of 21 months after construction (from August, 1993 to April, 19950 and nutrient release kinetics, the accumulated nutrient loads originating from the topsoil of the inundated land are about 81342 kg of nitrogen and 4701 kg of phosphorus.
The implications of point source phosphorus management to potable water treatment
Authors: Heath Ralph G. , Steynberg Machiel C. , Guglielmi Rita , Maritz Annelie L.
Published: May 2018

The Vaal River Barrage reservoir is an important source of raw water for Rand Water which supplies at least 10 million people with drinking water daily. Return effluents from waste water treatment works, industries and informal urban settlements in the catchment has resulted in algal problems in the raw water and treatment process.

In order to attempt to reduce the effect of eutrophication of South African inland water quality the Department of Water Affairs implemented in 1985 a 1 mg/l ortho-phosphate standard for waste water treatment works effluents.

The amount of phosphate originating from the waste treatment works decreased significantly over the 10 years after the standard was implemented even though 40% of the time the works do not comply to the standard. This has resulted in no significant change in the chlorophyll values at Rand Water Intake No. 1. The algal species composition has changed with blue-greens becoming more dominant which has resulted in a higher incidence of algal related problems. The stabilizing of the chlorophyll values is not only as a result of lower ortho-phosphate levels but also due to residence times, turbidity and conductivity.

To further reduce the algal concentrations at Rand Water Intake No. 1 the 1 mg/l ortho-phosphate standard will have to be enforced, the standard possibly reduced and diffuse sources managed on a catchment basis.
Oxygen transfer and aeration efficiency - influence of diffuser submergence, diffuser density, and blower type
Authors: Wagner Martin R. , Pöpel H. Johannes
Published: May 2018

The main factors of fine bubble aeration systems in uniform arrangement in clean water are the air flow rate, the depth of submergence of the diffusers, and the diffuser density. While the influence of the air flow rate on the oxygen transfer parameters is known, knowledge of the influence of the depth of submergence and the diffuser density on the specific oxygen transfer efficiency SOTE [%/m] and on the specific oxygen absorption SOA [g/m3·m at STP] is very limited. Both parameters are of great importance in dimensioning fine bubble aeration systems. Therefore, a literature review was conducted to show the influence of the diffuser submergence and density and the type of blower on oxygen transfer and aeration efficiency. The main review results are, that higher values of specific oxygen absorption can be obtained at higher diffuser density; secondly, the volumetric oxygen transfer rate VOTR [g/m3·h] is higher with increasing depth of submergence at the same air flow rate. Also it can be stated that with greater depth of submergence the specific oxygen absorption [g/m3·m at STP] is reduced. Dependent on the air flow rate and the pressure head, the energy consumption [Wh/m3·m at STP] of the blowers used in wastewater treatment plants is different. For example, the energy consumption varies from 4.3 [Wh/m3·m at STP] (positive displacement blower) to 3.0 [Wh/m3·m at STP] (turbo-compressors) at a pressure of 10 m and an air flow rate of 5,000 m3/h at STP.

From the results of the literature review the following conclusions can be drawn: (1) High specific oxygen absorption values (SOA) [g/m3·m at STP] can be achieved applying shallow tanks, high diffuser densities and low specific air flow rates; (2) High aeration efficiencies (AE) [kg/kWh] can be obtained by applying high volumetric oxygen transfer rates and adequate selection of the blowers used at the wastewater treatment plants.
Nitrogen and phosphorus losses from agriculture into surface waters; the effects of policies and measures in the Netherlands
Authors: Oenema O. , Roest C. W. J.
Published: May 2018

The increased input of fertilizers and animal wastes after 1950 has boosted agricultural crop production to a high level in many industrialized countries, but it has also contributed to increased nitrogen and phosphorus emissions from agriculture to groundwaters and surface waters. This paper summarizes the pathways and controls of nitrogen and phosphorus losses to surface waters, and it presents estimates and predictions of the losses from agricultural soils in The Netherlands into surface waters, before and after the implementation of policies and measures to reduce nutrient losses from agriculture.

Implementation of the nutrient accounting system MINAS, aiming at a step-wise lowering of nitrogen and phosphorus surpluses at farm level, will decrease the total nitrogen and phosphorus surpluses between the years 1985 and 2008 by 58 and 82%, respectively. These large decreases are the result of a strong decrease in the input via fertilizers and animal wastes, combined with only a minor decrease in the output via harvested products. Nitrogen emissions from agricultural land to surface waters will decrease by 38% between 1985 and 2008. Phosphorus emissions from agricultural land to surface waters are expected not to decrease on the short term.
Optimization of oxygen transfer in clean water by fine bubble diffused air system and separate mixing in aeration ditches
Authors: Déronzier G. , Duchène Ph. , Héduit A.
Published: May 2018

The influence of design parameters on the transfer of oxygen was studied in different ring ditches equipped with fine bubble membrane air diffusers and separate mixing. The results produced evidence that the oxygen transfer efficiency (OTE) decreases when the air flow rate per diffuser increases. OTE increases asymptotically with the horizontal water flow (50% for velocity up to 0.5 m/sec). It increases also when the diffuser modules are brought closer together. Theoretical analysis enabled ranking of the impact of the design parameters on which the oxygen transfer is dependent, namely the interfacial area (a) and the oxygen transfer coefficient (Kl). The increase in the air flow rate per diffuser essentially reduces the interfacial area by an increase in the diameter of the initial air bubbles and by a reduction of the contact time due to an acceleration of the “spiral flows” (vertical rotation of water flow). The horizontal rotation of water increases the interfacial area most probably by decreasing the diameter of the initial air bubbles and by a lengthening of the contact time resulting from a reduction in the large spiral flows. Bringing the diffuser modules closer together makes longer the contact time by a reduction in the large spiral flows.
Phosphorus-binding forms in the sediment of an oligotrophic and an eutrophic hardwater lake of the Baltic Lake District (Germany)
Authors: Gonsiorczyk Thomas , Casper Peter , Koschel Rainer
Published: May 2018

The vertical distribution of various phosphorus (P)-binding forms, associated potential P-binding partners and the composition of dry material were investigated in the bottom sediments of the dimictic oligotrophic Lake Stechlin and the dimictic eutrophic Lake Feldberger Haussee. Reductant soluble P (Fe- and Mn-bound) at the sediment surface (0−1 cm) was considerably higher in the oligotrophic Lake Stechlin (1.29 g kg−1) than in the eutrophic Lake Haussee (0.32 g kg−1). The amounts of dissolved, loosely adsorbed, metal oxide- and calcium carbonate bound P were higher in the eutrophic lake. The depth profiles of the investigated P species indicated that the mobilization of Fe- and Mn-bound P is the most important mechanism of P-release in oligotrophic lakes, whereas the mobilization of recently sedimented labile organic bound P seems to be the driving force of P-release in eutrophic lakes. In both lakes autochthonous calcite precipitations occurs during the summer months. The coprecipitation of P with calcite is an important self-cleaning mechanism in eutrophic hardwater lakes and contributes to the permanent burial of P in the sediments. Although, the precipitation of calcite is inhibited by the presence of high concentrations of soluble reactive P, the coprecipitation of P with calcite seems to be enhanced.
Liquid stream secondary treatment process design at the Annacis Island wastewater treatment plant of the Greater Vancouver sewerage and drainage district
Authors: Slezak L. A. , Fries M. K. , Pickard L. R. , Palsenbarg R. A.
Published: May 2018

The Greater Vancouver Sewerage & Drainage District (GVS&DD) is a major regional wastewater agency serving Vancouver, British Columbia and surrounding municipalities. In the late 1980's it was mandated to upgrade its largest treatment plant from primary treatment to secondary treatment. From 1990 until the present the GVS&DD has engaged in Predesign, Design, Construction and Commissioning of the Annacis Island WWTP Secondary Upgrade. The size of the facility and the fact that no secondary treatment components were previously in place combined to make the upgrade a very large project valued at nearly $470 million CDN. This paper describes the major project components of the liquid stream process improvements. In addition to the major biological treatment components, other aspects of the project are described including, odour management, influent pumping, and primary treatment upgrades.
Odour emission capacity of wastewaters - standardization of measurement method and application
Authors: Frechen Franz-Bernd , Köster Wulf
Published: May 2018

Odorous emissions from sewer systems and wastewater treatment plants can cause serious annoyance in the vicinity. Odorants which are present in a liquid phase are emitted into ambient air at the liquid-gaseous interface. The amount and the variation of emitted mass flow of odorants is significantly influenced by the amount of odorants which are present in the liquid. Up to now, however, no measurement method was available to describe this parameter, which can be called “Odorants Emission Capacity”. The paper describes a standardized method of determining the “Odorants Emission Capacity” and shows results and consequences from several case studies where this new method was applied.