bluuebunny/crossref_metadata_2025 huggingface dataset:
Engineering aspects of supercritical water oxidation
Authors: Gloyna E. F. , Li L. , McBrayer R. N.
Published: May 2018

This paper emphasizes the engineering aspects of supercritical water oxidation (SCWO), including organic destruction, inorganic solubility, corrosion, catalysis, heat transfer, and treatability studies. The development program involving a 2.5 liter-per-minute SCWO pilot-plant is described. Also, design considerations for the commercial SCWO processing facility, including materials of construction, reactor design, heat recovery, control strategy, safety requirements, and process integration are discussed.

The University of Texas at Austin (UT) and Eco Waste Technologies (EWT), respectively, are involved in research and development of SCWO technology. This R&D effort has resulted in the design and construction of a commercial SCWO processing facility for the Texaco Chemical Company located in Austin, Texas. The facility will become operational in early 1994.

SCWO technology relies on the unique properties of supercritical water to create a useful and effective reaction medium. The SCWO system is capable of operating as a totally enclosed treatment facility, providing complete destruction, and meeting regulatory effluent requirements. As such, this technology is an environmentally attractive, safe and economic wastewater treatment and sludge disposal option.
Membrane bioreactor treatment of oily wastes from a metal transformation mill
Authors: Zaloum Ronald , Lessard Serge , Mourato Diana , Carrière Julie
Published: May 2018

The performance of a membrane bioreactor treating wastewater from a metal transformation industry was compared with the ultrafiltration system at the mill. Toxicity analysis using the microtox and algal tests on the untreated and treated effluents from both systems showed a 130 fold reduction in toxicity due to the ultrafiltration step and a further 10 fold reduction due to the biological step. This resulted in a biomass which must be disposed of as a hazardous waste. In comparison with the present situation, the overall quantity of hazardous waste was reduced by a factor of 3 due to the combination of the bioreactor and the ultrafilters.
Development of a Pretreatment Program to Improve Biological Treatability of High Strength and Toxic Industrial Wastewater
Authors: Brenner A. , Belkin S. , Abeliovich A.
Published: May 2018

A biological treatment process has been suggested as the main treatment stage for a high (organic) strength industrial wastewater stream, discharged by several chemical industries within a large industrial park. Treatability studies have indicated that the wastes contain a fraction of toxic and non-biodegradable organic matter, which limits the implementation of a conventional biological treatment process for the combined wastewater stream. Therefore, an in-plant control program including waste segregation and process-specific pretreatments is proposed. A protocol that enables selection of waste streams amenable to biological treatment and identification of problematic streams requiring pretreatment is presented and demonstrated. It includes simplified laboratory procedures used for chemical and toxicological characterization of source streams originating in various processes. The results can be used for the development of a pretreatment program for problematic waste streams, based upon local small-scale solutions.
Treatment and Pretreatment Requirements for Industrial Wastewaters in Municipal Activated Sludge Plants
Authors: Wesley Eckenfelder W. , Musterman John L.
Published: May 2018

Industrial wastewaters may have a significant impact on municipal activated sludge plants. Depending on the degradability of the wastewater, the overall reaction coefficient, K, may be increased or decreased. Readily degradable wastewaters will render the process more susceptible to filamentous bulking. Increasing the soluble BOD fraction will increase the temperature effect. Sludge dewaterability may be decreased with readily degradable soluble wastewaters or increased with pulp and paper mill wastewaters containing pulp and fibre. Volatile organics which do not biodegrade require source treatment. Effluent toxicity should be controlled by industrial pretreatment where possible. In some cases, PAC will eliminate toxicity in the activated sludge process.
The microbial growth of Mycobacterium aurum L1 on vinyl chloride with respect to inhibitory and limiting influence of substrate and oxygen
Authors: Hauschild I. , Schröer A. , Siedersleben M. , Starnick J.
Published: May 2018

Vinyl chloride (VC) can be biodegraded aerobically by the strain Myobacterium aurum L1 to CO2 and HCl. The influence of VC and oxygen concentrations on microbial growth and VC utilization rate was examined in fed-batch experiments in a stirred tank reactor (STR) and a bubble column (BC). VC and oxygen show limiting and inhibitory effects. The kinetics can be described by a double Haldane model. The kinetic parameters were determined by a numerical optimization using the Simplex method.
Treatment of Effluents from Hemp-Based Pulp and Paper Industry II. Biological Treatability of Pulping Effluents
Authors: Gökçay Celai F. , Dilek Filiz B.
Published: May 2018

This paper is focussed on the biological treatability studies of pulping effluents from a hemp-based pulp and paper industry. Experiments were conducted by using white fungus, Phanerochaete chrysosporium, in a laboratory batch reactor. It was found that the colour removal efficiency is 75% for pulping effluents in the presence of high concentrations of glucose.
Design of Pre-Acidification Reactors for the Anaerobic Treatment of Industrial Wastewaters
Authors: Alexiou I. E. , Anderson G. K. , Evison L. M.
Published: May 2018

Two-phase anaerobic digestion has often been considered beneficial for the treatment of high strength industrial wastewaters, especially when the first phase is used as a pre-treatment system known as pre-acidification. Several applications in the field of industrial wastewater treatment have been reviewed in order to evaluate the advantages of the pre-acidification process and its effects on the methanogenic reactor. Although pre-acidification has obvious advantages, complete acidification may be detrimental to the efficiency of the overall process. The use of balancing tanks at full-scale has been common practice for the pre-acidification of a wide range of wastewaters yet no accepted design criteria for acidogenic reactors have been formulated and two-phase applications are generally based upon previous experience. The paper summarizes the results of a two year investigation into pre-acidification at both bench- and pilot-scale, presents the results of instant coffee production wastewaters and discusses a wide range of parameters which have been evaluated. Operating criteria will be discussed and guidelines for the design of pre-acidification reactors will be presented. Finally alternatives to using the total VFA (volatile fatty acids) concentrations for expressing the efficiency of acidogenesis will be introduced.
An Investigation into the Pre-Treatment of Dairy Wastewater Prior to Aerobic Biological Treatment
Authors: Kasapgil B. , Anderson G. K. , Ince O.
Published: May 2018

Implementation of the EC Directive on Urban Wastewater Treatment has led to the introduction of more stringent discharge standards being imposed by the Regulating Agencies in the United Kingdom. It is for this reason that this investigation into the pre-treatment of a dairy wastewater prior to aerobic biological treatment was carried out. In order to upgrade the existing treatment plant at a local dairy a Dissolved Air Flotation (DAF) and an anaerobic digestion system as pre-treatment process were studied at pilot - scale. Results obtained from this study showed that the existing aerobic biological treatment plant failed to achieve both the present consent conditions and those required in 1995. It was shown that an anaerobic filter would enable the plant to meet the discharge standards proposed by the National Rivers Authority but due to the configuration of the land available for new works it is recommended that the existing aerobic biological filter be replaced by an activated sludge system. It is anticipated that such a system would reduce the final effluent COD to less than 125 mg/l.
Particle destabilization for tertiary treatment of municipal wastewater by filtration
Authors: Ghosh M. , Amirtharajah A. , Adin A.
Published: May 2018

Optimization of the chemical pretreatment process prior to tertiary filtration of municipal secondary effluent was studied. Jar tests involving coagulation with alum, flocculation, settling and filtration were conducted on secondary effluent samples and these established the occurrence of two distinct coagulation mechanisms: the mechanism of charge neutralization, and the mechanism of sweep coagulation at different alum dosages and pH conditions. An optimum design region on the alum coagulation diagram also was established where the removals of various wastewater parameters were the highest. This region was bound by alum dosages of 55 to 60 mg/l and pH values of 6 to 6.5. In the above domain, the BOD5, TOC, turbidity, total-P, and the orthophosphate levels of the secondary effluent were reduced by 73%, 57%, 98%, and 99% respectively after tertiary filtration. Particle size analysis of the settled and filtered effluent also was conducted in both the charge neutralization and the sweep coagulation zones. A wide difference was observed in particle sizes between the effluents after settling and after filtration in the charge neutralization zone. In comparison, the difference in particle size between the settled and the filtered effluents was smaller in the sweep coagulation zone.
Biological Removal of Nitrogen in Toxic Industrial Effluents, High in Ammonia
Authors: Brønd Søren , Sund Christina
Published: May 2018

Industrial wastewaters with high ammonia concentrations, high toxicity and/or unfavourable COD/N ratio call for special attention and concern with regard to design and operation of the wastewater treatment system. Two cases are described: wastewater from a rendering plant and from a coke oven plant.

The precondition for obtaining and maintaining a nitrification process in both a rendering plant and a coke oven plant is close control and regulation of pH in the process tanks. Both high and low values of pH cause inhibition of the nitrifiers. pH should be kept in the range 6.5-7.0.

The organic fraction at the rendering plant mainly consists of easily biodegradable organic acids. The BIO-DENITRO concept has been chosen for this application and proven to be very efficient to obtain low effluent values for (NH3 + NH4)-N due to the flexibility in adjusting the phase length under variation in loadings and wastewater composition. Complete denitrification could be obtained with COD/N ratio larger than 5.

Wastewater from a coke oven plant contains compounds that are extremely toxic to the nitrifiers as for example phenol, cyanide, thiocyanate, sulphide and ammonia. Sufficient upstream buffering is essential to prevent shock loads. In order to obtain complete denitrification at the coke oven plant by using an internal carbon source, it is necessary to have an efficient ammonia stripping and phenol must not be removed from wastewater. COD/N ratio must be larger than 8 to obtain complete denitrification.
Treatment of Strong Wastewaters by Fixed Bed Anaerobic Reactors with Organic Support
Authors: Guitonas A. , Paschalidis G. , Zouboulis A.
Published: May 2018

In this experimental study the treatment efficiency on a milk based synthetic organic waste is examined of a fixed bed reactor with immobilized cells in organic support (straw). The aim of this research effort was to demonstrate an anaerobic treatment system which is flexible enough and can be used widely at small agroindustrial units as a low-energy-demanding treatment system. It can also be possibly used for the stabilization of the organic support, which can consequently be incorporated for the faster evolution of the composting phenomenon. A significant number of concentrations at the entrance of the fixed bed reactor, with a volume of V = 10.7 1, constructed from plexiglass and downflow fed, has been applied at different hydraulic retention times and at different temperatures (35°, 25°, 15°C). The examined reactor operates in plug-flow mode and the conclusions that were drawn from the experiments, with the above anaerobic treatment system are as follow. The treatment system can treat high and low strength effluents with considerable treatment efficiency. It can treat low strength effluents, with sufficient treatment efficiency, at medium and low temperatures, for anaerobic digestion standards. The time for adaption between different applied loadings at the inlet is quite short, which indicates the considerable flexibility and utility of the system.
Treatability Studies and Process Design for Toxicity Reduction for a Synthetic Fiber Industry
Authors: Musterman J. L. , Flippin T. H.
Published: May 2018

A series of batch treatability screening tests were conducted to identify technologies suitable for removal of ethylenediamine (EDA) and aquatic toxicity in a wastewater discharge from a synthetic fiber plant. Air stripping, cation exchange resin, activated silica, macroreticular resin, granular activated carbon and bio-hydrolysis were evaluated. Only cation exchange resin and bio-hydrolysis reduced effluent toxicity to the required limit. Continuous flow bench-scale activated sludge treatability tests were conducted over a four month period under simulated warm and cold weather operating conditions. The results confirmed that activated sludge treatment alone could consistently provide greater than 95 percent BOD reduction and complete EDA hydrolysis, nitrification and toxicity reduction. Toxicity reduction could be accomplished at high organic loading (F/M > 1.0/day) but hydrolysis of EDA caused an effluent NH3-N concentration of greater than 300 mg/L. A lower organic loading (F/M <0.30/day) was therefore selected to provide nitrification for compliance with the 25 mg/L NH3-N pretreatment limit. Alternatively, a high rate activated sludge system (F/M > 1.0/day) coupled with high pH air stripping of ammonia was considered in “desktop” evaluations. A detailed process design and cost estimate were developed.
Surface water quality monitoring, classification, biological assessment and standards
Authors: Newman Peter J. , Nixon Stephen C. , Rees Yvonne J.
Published: May 2018

Poor surface water quality is still a significant problem in many parts of the world. It can often limit the use of this vital resource and in more extreme cases can harm human and other life. A basic need is to establish the nature, extent and magnitude of the problems. To gain a quantitative picture it is necessary to undertake detailed quality and status assessments. Such assessments establish the scope of environmental impacts and effects, and provide a quantitative baseline against which future quality can be compared and progress monitored. Quality assessments or status reviews would enable the key problems and issues to be defined, and their magnitude and importance quantified. Problems for priority action can then be identified. Once key problems have been identified there are mechanisms to enact improvements and changes. These include the setting of standards and targets for water and sediment quality, quite often for defined actual or potential uses of the waters, such as for example for potable water supply and for fisheries. Compliance with the standards and progression towards the targets has to be assessed generally through appropriate monitoring. Monitoring might include biological as well as chemical and physical measurements of quality, and these might also be expressed as some form of index of quality. Periodic assessments of general quality on a national or international basis are also used to monitor overall progress. Nationally this might entail the use of general classification schemes expressing quality as a combined index or score, or individually for different components of the aquatic system, e.g. chemical, biological, aesthetic, and sediment quality.
Developments in water quality standards and classification schemes in England and Wales
Authors: Seager J.
Published: May 2018

This paper discusses the changes in national water quality classification schemes in England and Wales that have been proposed following the introduction of new legislation. The conclusion has been reached that two separate systems are necessary. A new General Quality Assessment scheme has been introduced for the purpose of assessing and reporting upon status and trends in water quality. A separate system of Use Classifications will be progressively introduced to drive the water quality planning process through the setting of Water Quality Objectives on a statutory basis. Recent advances in ecotoxicology have provided the opportunity for the development of new, more ecologically relevant, approaches to deriving water quality standards. One example of this is the development of criteria relevant to rivers affected by intermittent pollution for which alternative ways of expressing standards have been proposed and applied in conjunction with dynamic impact modelling techniques.
Effect of flow velocity on phosphate release from sediment
Authors: Nakamura Yoshiyuki
Published: May 2018

A mathematical model of phosphate release rate from sediment, fp, is presented which determines the fp as a function of flow velocity over the sediment and dissolved oxygen concentration. Oxygen consumption in the sediment is expressed as the sum of chemical consumption due to ferrous iron oxygenation and the bacterial consumption which is assumed to be a first order reaction of oxygen. At very low flow velocities, transport through the diffusive boundary layer is the limiting factor of SOD, and phosphate release rate is expressed as a linear decreasing function of the velocity. When flow velocities are increased, both SOD and phosphate release rate become independent of velocity, since the reactions in the sediment are the rate limiting factor. The model suggests that phosphate release flux is a linear decreasing function of DO in the bulk water, while SOD is an increasing function of DO concentration. The critical DO concentration at which the phosphate release ceases is expressed in terms of the flow velocity. The prediction of SOD and ϕp by the present model is favourably compared with experiments by former researchers.
Denitrification with isopropanol as a carbon source in a biofilm system
Authors: Hwang Yongwoo , Sakuma Hiroshi , Tanaka Toshihiro
Published: May 2018

Several batch tests and pilot-scale investigations on biological denitrification with isopropanol were performed. Isopropanol was converted to acetone by microbial oxidation during denitrification. Isopropanol itself little contributed to denitrification in practice while the converted acetone played a role of a main hydrogen donor. A larger quantity of nitrite intermediate was formed by using methanol compared to the case of isopropanol. The measured requirement of isopropanol was 2.0 mg mg−1 NO3-N, and was 2/3 of methanol. The oxygen equivalent of isopropanol for nitrate removal was almost the same as that of methanol. The denitrifier net growth yield for isopropanol was greater than for methanol. In order to maximize the denitrification rate, it is essential to convert isopropanol to acetone rapidly by accurate dosing for nitrogen load because the denitrification rate was accelerated by using acetone only. Excessive dose of isopropanol can cause a decrease in the denitrification rate as well as an increase of BOD in the effluent.
Temperature effect on nitrifying bacteria activity in biofilters: activation and free ammonia inhibition
Authors: Fdz-Polanco F. , Villaverde S. , García P. A.
Published: May 2018

Nitrifying bacteria activity and concentrations depend on specific free ammonia concentration (ratio NH3/biomass), that is a function of temperature, pH, ammonium concentration and nitrifying biomass concentration. So, temperature is a key parameter in the nitrification process producing two opposite effects: bacteria activation and free ammonia inhibition. These phenomena are studied in an up-flow biological aerated filter (UBAF) settled by a nitrifying biofilm (measured as Volatile Attached Solids, VAS). The plug flow allows to disclosure of both effects, activation and inhibition. For Nitrosomonas bacteria only an activation effect was observed; their activity reaches a maximum at 28-29 °C. For Nitrobacter the free ammonia inhibition prevails against the activation effect for values greater than 1 mg N-NH3/mg VAS allowing nitrite accumulation of 80%; this inhibition threshold value for nitrifying biofilm is obtained measuring the specific rate of utilization of substratum per unit of biomass (μmax/Y) by activity test. The knowledge of this threshold in a biofilm process is fundamental in order to control the nitrite accumulation in nitrifying biofilm reactors.
Organic carbon supplement influencing performance of biological nitritification in a fluidized bed reactor
Authors: Cheng Sheng-Shung , Chen Wen-Chin
Published: May 2018

A three-phase draft-tube fluidized-bed bioreactor packed with granular activated carbon (GAC) was employed to start up a nitrification process for high-strength ammonium (500 mg/l as N) wastewater. Supplement of sucrose into the ammonium wastewater was expected to enhance the attachment of nitrifier biofilm on GAC medium, and also to promote a high rate of ammonium conversion to predominant nitrite, i.e. nitrification process. In this study, various concentrations of sucrose provided various COD/NH4+-N ratios (0 to 1) to the fluidized bed bioreactor with an extremely high loading of 2.0 kg NH4+-N/m3-day and a limited air supply at the dissolved oxygen level of 3.0 mg/l. The results clearly indicated that the addition of organic carbon would inhibit the bioactivity of ammonium oxidizer (Nitrosomonas sp.) and nitrite oxidizer (Nitrobacter sp.). When the COD/NH4+-N ratio was increased to 0.33, the applied sludge loading to the nitrite oxidizer was greater than the specific substrate utilization rate, so the intermediate product, nitrite was accumulated without further nitratification. While the COD/NH4+-N ratio was increased to 1.0, a significant nitrite accumulation above 95% was achieved with the high ammonium feeding concentration of 500 mg/l NH4+-N. Meantime, the addition of sucrose in the start-up stage promoted heterotrophic growth and biofilm attachment on GAC surface. The filamentous structure of heterotrophs provided a biofilm surface on which the discrete nitrifying bacteria could be easily entrapped. In this fluidized-bed reactor, a large amount of entrapped nitrifier and a high efficiency of oxygen transfer rate had contributed to a high removal loading rate of ammonium with short hydraulic retention time of 6 hours.
Interpretation of bacterial activities in nitrification filters by a biofilm model considering the kinetics of soluble microbial products
Authors: Furumai H. , Rittmann B. E.
Published: May 2018

Activities of heterotrophic bacteria in nonsteady-state biofilms were evaluated using a simplified biofilm model in which formation and exchange of soluble microbial products (SMP) by nitrifiers and heterotrophs were considered. The model was applied to experimental results for a trace-level substrate removal. The model predictions indicated that SMP from nitrifiers contributed to supporting heterotrophic growth and their substrate removal potential. The biological interactions were more significant in cases of low influent substrate COD concentrations and increased with higher influent ammonium concentration. The introduction of SMP kinetics into the model captured the key aspects of removal and formation of COD components in biofilms receiving low influent substrate concentrations, such as nitrification filters for drinking water treatment and wastewater reuse.
On-line monitoring of anaerobic digestion: application of a device for continuous measurement of bicarbonate alkalinity
Authors: Hawkes Freda R. , Guwy Alan J. , Hawkes Dennis L. , Rozzi Alberto G.
Published: May 2018

Alkalinity or pH buffering capacity in anaerobic digesters is chiefly a function of bicarbonate levels, and should be within 10 to 50 mM for stable operation. A novel on-line instrument for measuring bicarbonate alkalinity has been developed, independent of titration techniques.

Using a 10 litre anaerobic filter digester operating on ice-cream wastewater, on-line measurements were made of bicarbonate alkalinity, pH, gas production and % CO2 and hydrogen concentration in the biogas during periods of organic overload. The bicarbonate alkalinity monitor was shown to be an effective instrument for monitoring instability of anaerobic digestion, and a useful tool for early warning of overloading. Moreover, in digesters fed with wastewaters containing low potential alkalinity, it allows indirect on-line determination of variations in volatile fatty acid concentration. Finally, used in conjunction with a sensor that measures CO2 in the gas, it allows an indirect but accurate determination of pH in those solutions where fouling of electrodes is severe.
Behavior of suspended solids and anaerobic bacteria in an anaerobic fixed bed reactor
Authors: Miyahara T. , Noike T.
Published: May 2018

Effects of packing of the filter media on substrate degradation and on behavior of anaerobic bacteria were investigated using an upflow anaerobic fixed bed reactor operated at 20°C. A low strength synthetic wastewater containing suspended solids was used as the substrate. Here, cellulose corresponds to suspended solids in domestic sewage. The effluent water quality is improved remarkably by packing of the filter media. Packing of the filter media promotes the degradation of insoluble matter as well as soluble matter of the influent. Insoluble matter (cellulose) in the influent does not accumulate in the interstitial space of the filter media and on the surface of the filter media, but acclimates in the lower part of the reactor. Packing of the filter media promotes the accumulation of lipolytic bacteria, acetate consuming methanogenic bacteria and hydrogen consuming methanogenic bacteria in the space where filter media were packed. Hydrolysis reaction of cellulose is promoted by packing of the filter media.
Coagulation and flocculation of stormwater from a separate sewer system – a new possibility for enhanced treatment
Authors: Heinzmann Bernd
Published: May 2018

With the upgrading of the wastewater treatment plants in Berlin, the significance of stormwater as a loading factor for receiving waters increases. Therefore it is important to ensure an adequate treatment of the stormwater from a separate sewer system. The preliminary tests have shown that for a coagulation and flocculation of the weakly buffered and very soft stormwater polyaluminium chloride (with a share of cationic flocculant aid), which reacts less acidic, is especially suitable. The optimum dose is 0.06 mmol/l Al3+, whereby the pH value has never fallen below 6. The colloids (as a rule a negative charge) have been destabilized by the mechanism of adsorption coagulation. Sometimes the mechanism of sweep coagulation came into operation. In the pilot plant investigations it was possible to work with a constant dosage of polyaluminium chloride because the pH value and the acid combining capacity during the stormwater flow remained relatively unchanged. The best enhanced stormwater treatment process is coagulation and flocculation in a pipe designed for both microfloc and macrofloc formation and separation by filtration. In this case, in particular phosphate, organic compounds, filterable solids and anthropogenic substances, e.g. lead (a high portion of which comes into receiving waters in Berlin by stormwater) and copper could be removed. These results indicate that, in general, this process works more efficiently than a stormwater tank where only particles can settle. The results were basically used for a draft concept for enhanced treatment of stormwater runoff from the motorway Avus in Berlin. The following treatment process should be implemented: coagulation and flocculation in pipes, sedimentation, filtration and percolation into the underground. Through the storage of stormwater before treatment a smaller treatment plant can be constructed and problems due to flow variations may be avoided. The storage should take place in a stormwater drainage system with a larger than normal volume. The cost for this treatment concept is approximately 10 % to 40 % higher than the cost of the treatment in a stormwater tank.
Use of lime for the upgrading of existing wastewater treatment systems
Authors: Güldner C. , Hegemann W. , Peschen N. , Sölter K.
Published: May 2018

The integration of the chemical precipitation unit which would inject a lime solution into a series of mechanical-biological processes, including nitrification/denitrification, and the sludge treatment are the subject of this project. The essential target is the large-scale reconstruction of a mechanical-biological sewage treatment plant with insufficient cleaning performance in the new German states and the adjustment of the precipitation stage to the unsteady inflow of sewage. First results indicate that the pre-treatment performance could be improved by ≅ 20% and the discharge of concentrations of COD, BOD, N and P could be reduced and homogenized. In addition, experiments on hydrolysis and acidifiability of the pre-treatment sludge have been carried out on a laboratory level with the object of making sources of carbon readily available for denitrification. In the course of the experiment, inhibition of fatty acid production by calcareous primary sludge could not be detected. The characteristics of the sludge, such as draining and thickening were considerably improved by the adding of lime.
Anaerobic filter and DSFF reactors in anaerobic treatment of tuna processing wastewater
Authors: Veiga M. C. , Méndez R. , Lema J. M.
Published: May 2018

An anaerobic filter (AF) and a downflow stationary fixed film (DSFF) reactor were used for the treatment of a tuna processing wastewater. Start-up of the anaerobic reactors was improved using lactose as co-substrate. The AF removed up to 75% of the influent COD concentrations at organic loading rates (OLR) of 11-13 kg COD m−3 d−1, whereas the DSFF reactor removed 70% at 3 kg COD m−3 d−1.

Based on these results it appears that anaerobic treatment systems are applicable to tuna processing industry wastewaters and that the AF shows a much better performance, allowing higher organic loadings and COD removal efficiencies than the DSFF reactor.
Sediment Transport over Deposited Beds in Sewers
Authors: Nalluri C. , Ghani A. Ab. , El-Zaemey A. K S.
Published: May 2018

This paper is based on an extensive experimental investigation of bedload transport of noncohesive sediments at “limit deposition” in channels of circular and rectangular cross-section. The effect of permanent deposits on the invert of pipe channels on sediment carrying capacity and hydraulic resistance to flow is investigated. The sediment transport data from rectangular and pipe channels led to the development of empirical equations with high correlation coefficients. These equations showed the possibilities of their validity for either channel shape with the incorporation of appropriate shape parameters.
An Evaluation of the Toxic Influences on Asellus Aquaticus (L) in an Urban Stream Environment
Authors: Mulliss R. , Ellis J. B. , Revitt D. M. , Shutes R. B. E.
Published: May 2018

Individually caged asellids placed in urban receiving waters were subjected to discharges from stormwater and combined sewer overflow outfalls. In each field trial the volume of precipitation and the number of dry days were recorded on a weekly basis and the metal (copper, zinc, cadmium, lead) body concentrations of caged organisms were measured. Using Principal Component Analysis (PCA), combinations of the measured parameters which explained much of the variation in organism mortality or changes in the weight of caged asellids were isolated. Three different sets of variable combinations were identified, two of which explained significant independent sources of variation responsible for changes in organism weight and one which explained a significant source of the variation in asellid mortality. Organism mortality and weight change were selected as dependent variables and regressed against the principal components of the independent variable predictors to produce empirical first order regression equations. Changes in the weight of caged organisms were found to result from the joint interaction of a number of identified variables. Copper was identified as being the most important metal toxicant with respect to mortality. Meteorological variables were found to have a greater influence on organism mortality than upon changes in organism weight.
Houses with Wet Feet: Ground Water Nuisance and its Abatement in the Netherlands
Authors: van de Ven Frans H. M.
Published: May 2018

Nuisance due to high groundwater levels is common in many urban areas in the Netherlands. The combination of adverse soil conditions for drainage, the wet climate and insufficient drainage facilities lead to mildew on walls, a fuggy smell, inaccessible playgrounds, weak road foundations, and so on. Insufficient preparation of the building sites is the main cause of the problems. This is a consequence of the responsibilities for the groundwater control are not clearly defined among the municipality, the inhabitants or others. Agreement on this distribution of responsibilities was recently achieved. Effective methods for designing and implementing a proper drainage system are available, although rather primitive. Data for solving the design problem with more sophisticated methods are, however, rarely available.
Impacts of Leakage Water from Urban Solid Waste Deposits on Ground Water Quality
Authors: Massing H.
Published: May 2018

Urbanized areas world-wide are characterized by, among other things, a high production of wastes of different types. More than 90% of urban solid wastes is brought to deposits. If the waste dumps or landfills are not designed, constructed, managed, and finally recultivated, according to the state of the art, dangerous impacts, especially on urban groundwater, can be expected. Percolating water from rainfall or surface overflow is strongly influenced by the components, the construction and the chemical/biological processes in the deposits. The leakage water has to be considered one of the most polluted and extremely unpredictable waste waters. Percolating into the natural groundwater has the effect that this resource is spoiled and no longer suitable for human use or as a component of ecosystems. Old waste dumps must restored and recultivated.
Design of a Snow Melting Tank Using Treated Wastewater
Authors: Maeda T. , Kinoshita S. , Sato S. , Ujiie A.
Published: May 2018

Iwamizawa City, which is located at lat. 43 deg N. and long. 141 deg E., on Hokkaido Island, in the northern part of Japan, experiences heavy snowfall during winter. Every year, the City disposes 610,000 tons of snow collected from its roads and spends 573 million yen for snow removal and 48 million yen for maintenance of the snow dumping sites. However, these dumping sites have, at present, almost reached the limit of their capacities. It is for this reason that snow melting and disposal with treated wastewater was planned. In planning the equalization tank at Nankoen Wastewater Treatment Plant (NWTP), the City intended to use the tank for snow melting during winter. As there were no available data for designing such a tank, experiments were conducted to generate data necessary for designing the snow melting tank. The full-scale tank was constructed based on findings and results of the series of experiments. Results of operation show stable snow disposal and cost reduction for snow removal.
Operational Experience with Vortex Solids Separators for Combined Sewer Overflow (CSO) Control
Authors: Pisano William C. , Brombach Hans
Published: May 2018

The first vortex solids separator facility in Germany for CSO control was installed in 1987. Solids separation efficiency was optimized in the hydraulic laboratory using scaled down models and artificial tracers to simulate typical sewage particulates. The facility comprises two parallel operating vortex separators servicing an impervious area of 11 ha with a population of 1,500 people. The specific storage of the facility including the separator volume and in-line pipe storage is 7.2 m3/ha, about 1/4 - 1/2 of that required per German standards. A multi-year evaluation program was conducted. The first phase noted operational reliability, hydraulic loads and overflow frequencies. In the second phase pollutant removal efficiencies were monitored. The results were favourable indicating that the separator is now ready for use.
Optimization of Storage/Treatment Scheme for Combined Sewer Overflows
Authors: Ashamalla Adel , Bowering Ted , Parente Mario
Published: May 2018

The evaluation of various schemes to eliminate Combined Sewer Overflows (CSO) from the City of Toronto to the lower Don River and the shores of Lake Ontario resulted in the selection of a storage tunnel system, from which flows are pumped to a treatment facility before discharge to the receiving waters. This paper discusses the procedure used and the results obtained to optimize the combination of the storage volume and treatment rate to meet the required objectives.

To analyze the effectiveness of this scheme in reducing the number of overflow events and the total volume of the CSO, long term simulations were carried out. The City's Quantity-Quality Simulation model (QQS model, developed by Dorsch Consult) was calibrated and run for four years of rainfall record. These years were selected as two average precipitation years, a dry year and a wet year representing the last twenty years of precipitation record.

The model was used to predict the frequency of overflows resulting from different storage volumes (represented by tunnel sizes) and different treatment rates (represented by pumping rates from the tunnel). A family of curves was plotted using the QQS results, to present the relationship between the storage volume and the treatment rate vs. the effectiveness of the scheme presented by the resulting number of CSO events per year, and the percentage reduction in the overall annual CSO volume. To optimize the scheme the total cost of the storage and treatment was estimated, and a family of curves was produced among alternative schemes consisting of combinations of storage sizes and treatment rates, their effectiveness and their overall cost. The curves were plotted to present the effectiveness in the entire waterfront area, as well as the effectiveness in separate areas, since different water quality objectives were set up according to the water use activities in those areas. The procedure then identified the most cost effective combination of tunnel sizes and treatment capacity to meet the objectives in the different areas.
Characteristics of the Chlorinated Organic Substances in Filtrates from Bleaching of Oxygen-Delignified Eucalypt Kraft Pulp
Authors: Smith Terrence J. , Wearne Ross H. , Wallis Adrian F. A.
Published: May 2018

Oxygen-delignified kraft pulps from mature and young eucalypt woods were bleached with sequences involving chlorine (C), chlorine dioxide (D) and alkali-oxygen (EO). The bleaching filtrates were analysed for chlorinated organic compounds by gas chromatography with the use of a mass selective detector. Chlorinated compounds found included a range of chlorinated phenols, neutral compounds, aliphatic acids and phenolic acids. A total of 41 chlorinated phenols were identified, mostly in the filtrates following chlorination {(EO)[C]} and only few in the (EO)[D] filtrates. 2-Chlorosyringaldehyde was the only significant chlorinated phenol obtained after D-prebleaching. There was no indication of differences in the types of chlorinated phenols obtained from the mature and young eucalypt samples, although there were higher levels of phenols in filtrates from the younger wood sample. The dominant chlorinated neutral compounds found in the filtrates were chloroform, chloroacetones and chlorodimethylsulfones. Most chloroform and chloroacetones were found in the C-stage filtrates, while chlorodimethylsulfones were found in both C and D-stage filtrates to the same extent. An abundant compound with probable molecular formula C5H3ClO3 was also in the neutral fraction. The chloroacetic acids were the only aliphatic acids detected and were found in all filtrates examined. A method for the analysis of chlorinated phenolic acids involving sequential acetylation and methylation of the extracts was devised. Three chlorinated phenolic acids were identified in the filtrates as their methyl ester acetates. The total amount of chlorinated compounds analysed was consistently higher in the young eucalypt sample than in the mature sample, and correlated well with the generic parameters AOX and EOX. High molar mass (HMM) solids prepared from the C(EO) bleaching filtrates by ultrafiltration had higher chlorine contents than those from the D(EO) bleaching filtrates. Apparent molecular mass distributions of the HMM solids determined by high performance size exclusion chromatography were dependent on the method of detection.
Anaerobic and Aerobic Treatment for AOX Removal
Authors: Ferguson John F.
Published: May 2018

A two-year study has focused on AOX removal from bleaching wastewaters in anaerobic and aerobic biological treatment, using bench scale bioreactors operated in parallel and in series. Significantly higher removals have been found in anaerobic than in aerobic treatment. Earlier work with dilute kraft bleaching wastes has been extended in additional laboratory tests and at a nearby kraft mill. 50-75% fractions of bleaching wastes were treated. Toxicity in the anaerobic process was encountered at 85% bleach waste fractions.

Total AOX removal experienced in aerobic treatment is 30-35%, in anaerobic treatment 40-45%, and in an anaerobic/aerobic sequence 50-55%. Percentage removals were not sensitive to the fraction of bleaching wastewater. Several process modifications were attempted to try to obtain higher removals with only marginal success. Studies at a kraft mill confirmed the AOX removals that had been found in lab studies.

AOX removal occurs by several mechanisms. There is a very significant chemical or abiotic degradation that occurs after neutralization, perhaps enhanced by reductants or other inorganic salts. Biological processes are much more significant in anaerobic than in aerobic treatment. Anaerobic reductive dehalogenation affects specific chlorinated compounds and catalyzed AOX degradation is facilitated by reduced coenzymes that are produced by bacteria. Removal by sorption or insolubilization is relatively minor in aerobic and anaerobic processes.
Advanced Treatment of Paper Mill Wastewaters
Authors: Möbius Christian H. , Cordes-Tolle Maria
Published: May 2018

Improved external treatment of wastewater has become necessary for an increasing number of paper mills in view of stringent regulations governing the protection of receiving waters. Some of these advanced treatment processes have been shown to be useful after conventional primary treatment of wastewater with low concentrations of organics resulting from wood free paper production. For more contaminated wastewaters these state of the art techniques can also be used to supplement regular treatment like activated sludge processes. In these cases the advanced treatment processes are the final stage of a chain of mechanical, physico-chemical and biological treatment steps.

The equipment and processes used for advanced treatment are sand filters, biofilters, low-capacity trickling filters, flocculation and precipitation with inorganic salts in combination with filtration or flotation. These procedures are designed mainly for a reduction in concentrations of suspended solids, COD, and phosphorus.

Examples of the technical operation of these processes are presented. Compared to the results of standard treatment processes the results of the advanced treatment are a significant improvement As requirements for effluent quality will be maximized in industrialized countries in the near future - if this has not already been done - these processes will be needed, even if the costs are high.
Combined Anaerobic/Aerobic Treatment of Peroxide Bleached TMP Mill Effluent
Authors: Driessen W. J. B. M. , Wasenius C.-O.
Published: May 2018

In this paper combined anaerobic/aerobic treatment is illustrated by two examples at integrated pulp and paper mills with peroxide bleached TMP pulp production.

The concept of combined biological treatment is to treat the more polluted effluents from the TMP pulp mill in an anaerobic reactor and subsequently to mix them with the less concentrated effluent, for treatment by an aerobic process.

Extensive pilot research was done to confirm the feasibility of anaerobic treatment of peroxide bleached TMP mill effluent COD removal efficiencies of 55-60% were achieved at volumetric loading rates of up to 20 kg/m3/d. Possible toxic effects from peroxide could easily be neutralized by removal in a preacidification tank.

Long term full scale experience proved that combined anaerobic aerobic treatment is an attractive and reliable method for treatment of peroxide bleached TMP mill effluent.
Anaerobic 35°C and 55°C Treatment of a BCTMP/TMP Effluent: Sulphur Management Strategies
Authors: Stephenson R. J. , Branion R. M. R. , Pinder K. L.
Published: May 2018

Pulp manufacture uses sulphur in a variety of forms and these sulphur compounds ultimately end up in the effluent. Under anaerobic conditions, sulphite and sulphate are reduced to sulphide, presenting problems of toxicity, odour, corrosion, and reduced methane yields and treatment efficiencies. The fate of these inorganic sulphur compounds in a bleached chemi-thermomechanical pulp/thermomechanical pulp (BCTMP/TMP) effluent mixture was examined in two phase anaerobic reactors at 35°C and 55°C. The following sulphur management strategies were investigated: 1) controlling the pH of the acidogenic reactor, 2) inhibiting the sulphur reducing bacteria via molybdenum addition to the feed tank, and 3) stripping the hydrogen sulphide dissolved in the methane phase reactor liquor by recycling hydrogen sulphide-free off gas. The laboratory scale experimental apparatus consisted of upflow anaerobic sludge bed pre-treatment or acidogenic reactors followed by hybrid upflow anaerobic sludge bed/fixed film methanogenic reactors.

At 35°C, controlling the pH of the acidogenic reactors with sodium carbonate from 5.5 (uncontrolled) to 8.0 in order to shift the formed sulphide species to the less toxic ionic form appeared to be ineffective in promoting wastewater treatment efficiency. Molybdenum addition to the wastewater at levels from 0.1 to 1.0 mM was effective at 1.0 mM in retarding sulphate reduction or sulphide formation. Hydrogen sulphide stripping, using ferric chloride scrubbed and recycled off gas, appeared to be the most effective means of sulphur management for this type of wastewater under these conditions.

Tbermophilic 55°C anaerobic treatment was also studied using the same effluent, inocula and sulphur management strategies. Overall, both the treatment efficiency and the sulphate reduction were lower for the thermophilic runs compared to the mesophilic runs. Raising the acidogenic phase reactor pH from 7.0 to 7.5 to 8.0 appeared to have no significant effect on organic carbon removal efficiency or on sulphate reduction. Molybdenum inhibition of sulphur reduction was not as marked as for the 1.0 mM level at 35°C, perhaps due to the already low baseline sulphate reduction efficiency at 55°C. Stripping hydrogen sulphide from the reactor liquor helped to promote the treatment efficiency and lowered the sulphide and sulphate levels. Similar to the 35°C study, sulphide removal by gas stripping appeared to be the most effective means of sulphur management