bluuebunny/crossref_metadata_2025 huggingface dataset:
Water Protection in the Pulp Industry: Austrian and Central European Situation
Authors: Kroiss H.
Published: May 2018

The pulp and paper industry in central Europe was for a long period one of the biggest water polluters. During the last 10 years the pollution load to the receiving waters has decreased to such an extent that a compromise between water protection and industrial development is in sight This positive achievement started with a concentration at the production in a relatively small number of mills with modern and cost effective production processes minimizing pollution discharge to the wastewater. Nearly all mills are equipped with biological wastewater treatment plants. Many mills have abandoned chlorine for bleaching, thus solving the AOX problem, some are on the way to doing this. These positive achievements are the result of a water protection and industrial development policy.
Characterization of Chlorinated Aromatic Structures in High Molecular Weight BKME-Materials and in Fulvic Acids from Industrially Unpolluted Waters
Authors: Dahlman O. , Reimann A. , Ljungquist P. , Mörck R. , Johansson C. , Borén H. , Grimvall A.
Published: May 2018

This paper presents the results of a comprehensive characterization of chlorinated aromatic structures in high molecular weight organic material from bleached kraft mill effluents (BKME) and industrially unpolluted surface waters and groundwaters. After oxidative degradation (permanganate) of the organic materials and derivatization (diazomethane) of the degradation products obtained, the occurrence of chlorinated aromatic degradation products was investigated using gas chromatography/mass spectrometry. About twenty chlorinated methyl esters of aromatic carboxylic acids were identified in degraded samples of both industrial and natural origin. The identified compounds originated from chlorinated 4-hydroxyphenyl, 3,4-dihydroxyphenyl, guaiacyl, “condensed” guaiacyl, syringyl and veratryl units present as structural elements in the high molecular weight organic materials studied. Degradation products originating from mono- and dichlorinated 4-hydroxyphenyl units dominated in the degraded samples from unpolluted environments, whereas degradation products originating from chlorinated guaiacyl and syringyl units were most abundant in the degraded softwood and hardwood BKME samples. A special study of the monochlorinated isomers of 4-ethoxy-3-methoxybenzoic acid methyl ester showed that the 6-chloro isomer dominated in the degraded BKME samples whereas about equal amounts of the 5-chloro and 6-chloro isomers were found in degraded fulvic acids isolated from unpolluted waters.
Bioavailability of Pulp and Paper Mill Effluent Phosphorus
Authors: Priha Maarit
Published: May 2018

The aim of this study was to examine the stability and bioavailability of different phosphorus fractions of pulp and paper mill effluents in order to assess the environmental benefits of reducing their phosphorus discharges. Two types of effluent were studied: activated sludge treated bleached kraft mill effluent and activated sludge treated paper mill effluent. Phosphorus was characterized on the basis of its solubility and chemical reactivity. The stability of particulate phosphorus was studied in long-term (6-8 weeks) degradation tests. The bioavailability of different phosphorus fractions was measured by algal growth potential tests.

In bleached kraft mill effluent (BKME) the proportion of dissolved phosphorus in relation to the total phosphorus was on an average 80%, and of this, approximately 80-90% was reactive phosphorus. During a 6-8 week incubation period some 60-70% of the particulate phosphorus in BKME was dissolved as soluble phosphorus, and most of it was of the reactive type. Approximately 90% of the dissolved phosphorus and 45% of the particulate phosphorus in BKME was biologically available phosphorus (BAP). Altogether some 80% of the total phosphorus in activated sludge treated BKME was available for algae either immediately or after inherent degradation.

The percentages of dissolved and particulate phosphorus of paper mill effluent (PME) total phosphorus were of the same order of magnitude as those of BKME, but less than 20% of the dissolved phosphorus was of the reactive type. Approximately 50-60% of the particulate phosphorus in PME was dissolved in degradation tests, and 90% of it was biologically available.
Environmental Impact Assessment - Valuable Experiences of EIA Procedure and Public Perception of Major Industrial Projects
Authors: Anhava Juhani , Kolehmainen Olli
Published: May 2018

Environmental Impact Assessment (EIA) is presented as a specialised tool for project management. Environmental assessment in different phases of the project cycle is discussed. Different approaches to the EIA process in some countries are briefly reviewed, and especially the possibilities for public participation are discussed. A number of examples of EIA in Australia, Canada, France, Germany and Spain are characterised and compared. The comparison includes four kraft pulp mills and one paper mill, and the main features of each EIA are presented.
Introduction of Bioremediation Ability into Granular Sludge
Authors: Christiansen N. , Ahring B. K.
Published: May 2018

Three 200 ml upflow anaerobic sludge blanket (UASB)-reactors were inoculated with sugar degrading granules. To impart 3-chlorobenzoate degrading ability to the reactors, one was inoculated with the 3-chlorobenzoate (3-CB) dechlorinating Desulfomonile tiedjei, and the second received a 3-CB dechlorinating consortium, consisting of D.tiedjei and a benzoate degrading coculture of Syntrophus buswellii with Methanospirillum sp. No degradation of 3-CB was observed in the third reactor only inoculated with granules. After several months operation at a hydraulic retention time at 0.5 day, shorter than the reported generation time of D. tiedjei, the reactors showed increasing dechlorinating abilities. Activity tests done with granules from the control and the consortium-inoculated reactor showed no activity in the control reactor and no significant difference in the specific dechlorination rate with granules from the top, middle or bottom layer of the active reactor sludge bed, with or without carbon source added. This indicated that the added bacteria were immobilized in the granules and they were responsible for the dechlorinating activity. These results have important implications for the use of pure anaerobic culture or defined microbial mixtures in viable waste treatment processes.
Overview of the Anaerobic Toxicity Caused by Organic Forest Industry Wastewater Pollutants
Authors: Sierra-Alvarez R. , Field J. A. , Kortekaas S. , Lettinga G.
Published: May 2018

Numerous types of organic environmental pollutants are encountered in forest industry effluents which potentially could inhibit consortia of anaerobic bacteria. The purpose of this study was to collect anaerobic bioassay data from the literature to better estimate the impact of these pollutants on anaerobic wastewater treatment systems.

The most important methanogenic inhibitors in forest industry wastewaters are wood resin, chlorophenols and tannins. These compounds account for toxicity in alkaline pulping liquors, bleaching effluents and debarking wastewaters, respectively. Adaptation to chlorophenol toxicity can be expected since they are eventually degraded in anaerobic systems. Wood resin compounds, on the other hand, are not biodegraded anaerobically and therefore their toxicity is persistent. Toxicity in forest industry wastewaters does not necessarily preclude anaerobic treatment. A variety of techniques can be employed to diminish inhibition, such as dilution and detoxification treatments.
Oxygen reduces denitrification in biofilm reactors
Authors: Hagedorn-Olsen C. , Møller I. H. , Tøttrup H. , Harremoës P.
Published: May 2018

The mechanism for the nitrate removal from wastewater in a submerged fixed film filter is reviewed and evaluated to demonstrate that the denitrification process is significantly reduced by the presence of oxygen.

The kinetics were developed for a fully nitrate penetrated biofilm, influenced by oxygen. It was demonstrated that there is a linear reduction of the denitrification rate with depth of oxygen penetration, proportional to the oxygen concentration to the half power. For a partly nitrate penetrated biofilm the influence of oxygen is a function of the ratio between the penetration of oxygen and the penetration of nitrate without the influence of oxygen.

The phenomenon was investigated in laboratory scale with biocarbone and biostyr as media and at a full scale biocarbone plant. The investigation was performed with organic matter in excess on a thin biofilm taken directly from a full scale plant. The results of the experiments with influence of oxygen fit the kinetic concepts well.
The optimum medium of the suspended bio-medium aeration contactor process
Authors: Ouyang C. F. , Liaw C. M.
Published: May 2018

The purpose of this study is to modify the Fluidized Bed Process. Placing various particle diameters of granular activated carbon, (#20∼#30, #30∼#40, #40∼#50) as a medium in an aeration tank, in which microorganisms can attach and grow, improves the biomass concentration, volumetric loadings and removal efficiency. The continuous supply of substrates allows the thickness of bio-film on the medium to be shifted to a proper state. This is due to a friction force effect between the media and the shear force of the agitated flow. After studying the comparisons, it is concluded that the middle particle size (#30∼#40) is the best of the three particle diameters as a medium, in that it achieves a high biomass concentration, stable treatment and higher efficiency.
Predicting bed dynamics in three-phase, fluidized-bed biofilm reactors
Authors: Chang H. T. , Rittmann B. E.
Published: May 2018

This paper presents a unified model that inter-relates gas flow rate, liquid flow rate, and hold-ups of each of the liquid, gas, and solid phases in three-phase, fluidized-bed biofilm (TPFBB) process. It describes how carrier properties, biofilm properties, and gas and liquid flow velocities control the system dynamics, which ultimately will affect the density, thickness, and distribution of the biofilm. The paper describes the development of the mathematical model to correlate the effects of gas flow rate, liquid flow rate, solid concentration, and biofilm thickness and density. This knowledge is critically needed in light of the use of TPFBB processes in treating industrial wastewater, which often has high substrate concentration. For example, the proper design of the TPFBB process requires mathematical description of the cause-effect relationship between biofilm growth and fluidization.
Competition in biofilms
Authors: Zhang T. C. , Fu Y. C. , Bishop P. L.
Published: May 2018

Competitions in biofilms for substrate and space have been studied by using a microelectrode technique and a microslicing technique. Three different kinds of biofilms, cultured by laboratory-scale rotating drum biofilm reactors (RDBR) with synthetic wastewater, have been used as test materials. Oxygen, ammonium-nitrogen, nitrate-nitrogen, and pH concentration profiles in the biofilms were measured using microelectrodes. Experimental results showed that: 1) an increase of organic loading rate would result in a decrease of DO concentration in the biofilm. However, after the organic loading rate exceeded a certain value, the oxygen profiles within the biofilm did not change any more; 2) Heterotrophs competed for oxygen with nitrifiers, which resulted in the inhibition of nitrification because of the shortage of oxygen. Glucose itself, however, did not inhibit the nitrification processes; and 3) The competition for substrate in biofilms resulted in a stratified biofilm structure. Experiments showed that competition in biofilms resulted in non-uniform spatial distributions of bacterial populations and metabolically active bacteria. The spatial distributions of biotic and abiotic components in turn affected the substrate transfer and substrate competition within the biofilm. Traditional biofilm modelling will fail in many cases if they are based on substrate removal kinetics and uniform distributions of biofilm properties.
The calculation of simultaneous effective diffusion coefficients of the substrates in a fluidized bed biofilm reactor
Authors: Beyenal H. , Tanyolaç A.
Published: May 2018

In this study, a pure culture of Zoogloea ramigera was film-wise grown on activated carbon particles in a differential fluidized bed biofilm reactor (DFBBR). In biofilm, effective diffusion coefficients of the essential substrates; glucose, ammonium chloride and dissolved oxygen were simultaneously calculated. The multisubstrate biokinetic expression used to calculate effective diffusion coefficients was derived by nonlinear regression analysis of the data of continuous fermenter experiments. This equation was utilized to solve diffusion & reaction model for effective diffusion coefficients in active biofilm. The results of the model solution revealed that the effective diffusion coefficient for all three substrates through the biofilm decreased with increasing biofilm density.
Decision aids for alternative techniques in urban storm management
Authors: Azzout Y. , Barraud S. , Cres F. N. , Alfakih E.
Published: May 2018

The choice of alternative techniques in urban stormwater drainage (infiltration and detention systems), in the course of a project, is most often made with a poor understanding of site constraints, and the possibilities afforded by these techniques. This gives rise to extra costs and also subsequent malfunctioning. To arrive at feasible choices, we have formalised the decision-making process, taking account of the multiple criteria and the large number of partners involved. At present, we are developing a decision-making tool for alternative techniques in urban stormwater management at the preliminary study stage. The first phase makes it possible to eliminate solutions which are unworkable (elimination phase). It is aimed at the designer. Work on the next phase (the decision-making phase), which is more complex, is in progress. It will make it possible, in collaboration with all the partners involved, to choose a stormwater drainage strategy which will best suit the objectives and the wishes of the partners. It uses multi-criteria methods.
Multiple interactions in riverine biofilms - surfactant adsorption, bacterial attachment and biodegradation
Authors: White Graham F.
Published: May 2018

Many organic pollutants, especially synthetic surfactants, adsorb onto solid surfaces in natural and engineered aquatic environments. Biofilm bacteria on such surfaces make major contributions to microbial heterotrophic activity and biodegradation of organic pollutants. This paper reviews evidence for multiple interactions between surfactants, biodegradative bacteria, and sediment-liquid interfaces. Biodegradable surfactants e.g. SDS, added to a river-water microcosm were rapidly adsorb to sediment surface and stimulated the indigenous bacteria to attach to the sediment particles. Recalcitrant surfactants and non-surfactant organic nutrients did not stimulate attachment Attachment of bacteria was maximal when biodegradation was fastest, and was reversed when biodegradation was complete. Dodecanol, the primary product of SDS-biodegradation, markedly stimulated attachment. When SDS was added to suspensions containing sediment and either known degraders or known non-degraders, only the degraders became attached, and attachment accelerated surfactant biodegradation to dodecanol. These cyclical cooperative interactions have implications for the design of biodegradability-tests, the impact of surfactant adjuvants on biodegradability of herbicides/pesticides formulated with surfactants, and the role of surfactants used to accelerate bioremediation of hydrocarbon-polluted soils.
Modeling biofilm biodegradation requiring cosubstrates: the quinoline example
Authors: Malmstead Michael J. , Brockman Fred J. , Valocchi Albert J. , Rittmann Bruce E.
Published: May 2018

The aerobic biodegradation of quinoline, a two-ring nitrogen heterocycle, offers an outstanding example of when structured modeling including cosubstrates is required for a biofilm system. In this case, the cosubstrate is oxygen, which is used as a direct cosubstrate in oxygenase reactions and as a primary electron acceptor in respiration. Quinoline biodegradation is numerically simulated as occurring in five key steps, two of which involve oxygen as a direct cosubstrate. Modeling evaluation of experimental results from a laboratory-scale biofilm column shows that the oxygenation steps are much more sensitive to low oxygen concentrations than are steps in which oxygen only participates through respiration. The result of this differential oxygen sensitivity is that the first intermediate product, 2-hydroxyquinoline, builds up, because its degradation through an oxygenase reaction is slowed preferentially by oxygen depletion.
A generic method of design of on-site stormwater detention storages
Authors: Phillips Donald Ian
Published: May 2018

On-site stormwater detention is widely used in Australia as a means of controlling the increased storm discharges from urban consolidation projects. However, unless the maximum permissible site discharge is correctly determined, the local piped drainage system may be overloaded. This paper presents a generic methodology that integrates detention storage behaviour with drainage design theory in such a manner as to protect the entire length of the downstream drainage system. Its generic nature facilitates its universal application to all systems, protecting these valuable community assets throughout their service lives.
Transport and reaction of aromatics, O2 and CO2 within a membrane bound biofilm in competition with suspended biomass
Authors: Debus Oliver
Published: May 2018

The biological removal of volatile o-, m-, p-xylene and ethylbenzene from the bulk fluid was investigated in a stirred laboratory reactor. The biofilm was grown on a gas-permeable silicone membrane tubing through which oxygen was supplied. A mathematical simulation could adequately reproduce the experimental values for the biofilm thickness and the concentrations for several species for both sides of the biofilm: in the bulk liquid and in the gas phase. A high xylene conversion plateau of more than 90% was determined by the chronologically occurrence of two sub-maxima: conversion by suspended biomass and by the biofilm. The two maxima can be explained by the spatial transport processes of oxygen and xylene in the biofilm. The first sub-maximum of the conversion by suspended biomass is determined by a maximum oxygen flux through the membrane-bound biofilm. Later oxygen becomes limiting in the bulk and less xylene is degraded by suspended biomass and a maximum transport of xylene into the biofilm occurred, which led to a maximum conversion of xylene within the biofilm. For biodegradable organic compounds, the biofilm can totally reduce the transfer of these compounds into the gas phase. If compounds are non-degradable a biofilm with a thickness of 2 mm reduces the transfer into the gas phase only by 35%. Therefore, the application of pure oxygen and low volumetric gas rates are necessary to reduce the transfer of compounds that are not biodegradable.

The transfer of CO2 into the gas phase of the membrane-bound biofilm is very important for the stabilization of the pH in the biofilm and the bulk. The transfer of CO2 from the biofilm into the gas phase is up to 6 times higher than the transfer of CO2 from the biofilm into the bulk. The pH-minimum in the biofilm is not more than 0.15 pH-units below the pH in the bulk.
Stormwater treatment by dissolved air flotation: first results from a pilot project
Authors: Bernard C. , Herviou P. , Poujol T.
Published: May 2018

A stormwater treatment plant using dissolved air flotation was operated in 1993, at the outlet of the Chelles River catchment area (Seine-et-Marne, France). The process was divided into two different stages. Firstly, a coagulation/flocculation stage, secondly a flotation stage in a flotation tank. The flow rate was set at 13 m3/h. Stormwater was the main part of the effluent but with some urban wastewater as the network is not strictly separate. The process efficiency was tested for suspended solids, chemical oxygen demand and hydrocarbons. A total hydrocarbon removal was observed. Finally, constant output concentrations were observed in spite of important input roughwater concentration variations.
Population distribution in aerobic biofilms on small suspended particles
Authors: van Loosdrecht M. C. M. , Tijhuis L. , Wijdieks A. M. S. , Heijnen J. J.
Published: May 2018

The population distribution of nitrifying and heterotrophic bacteria in biofilm particles from BAS reactors has been studied with the aid of an oxygen microelectrode. The oxygen fluxes to the biofilm surface calculated from the external diffusion profile corresponded well with volumetric uptake measurements in batch tests using a large number of particles. Measurements of internal oxygen concentrations in these small biofilm particles (radius: ≈ 0.5 mm) proved to be reproducible. The internal structure of the biofilm appeared to be highly heterogeneous, i.e. oxygen profiles differed between different sites on a biofilm particle and between different particles from the same sample. Despite the lateral heterogeneity it was possible to obtain a clear indication for the existence of a layered structure of nitrifying and heterotrophic bacteria in these biofilms. Simulation of the biofilm formation by a standard biofilm simulation model also (BIOSIM) revealed this layered structured. The segregation of autotrophs and nitrifiers was, however, to be stronger than could be described by BIOSIM. The results underline that for obtaining a stable conversion of substrates by slow growing organisms (ammonium, xenobiotics) a not too high biofilm surface specific substrate loading of fast degradable COD is required to ensure sufficient oxygen penetration to the layer with the slow-growing microorganisms.
The UK response to the challenge of Urban stormwater management
Authors: Clifforde Ian , Morris Gerard , Crabtree Bob
Published: May 2018

The United Kingdom has many environmental problems associated with the collection, treatment and disposal of stormwater which have arisen from historical inadequacies in technology, management and funding. The paper describes the changes that have occurred in recent years to strengthen and improve regulatory, financial and technological capabilities which will now allow progress to be made towards meeting the requirements of current legislation and public expectation.
Fluorescent dye measurements of the mixing and transport of wastewater discharge in the bosphorus
Authors: Özsoy Emin , Latif Mohammed Abdul , Besiktepe Sükrü T. , Gaines Alexander
Published: May 2018

The performance of the wastewater discharge of Istanbul is evaluated based on fluorescent dye technique, supported by hydrographic and current measurements. Under the normal exchange flows, as well as during extreme events of blocking, the dye essentially remained confined in the lower layer. The maximum upper layer average dye concentration in the Bosphorus was close to the background levels, while the interfacial layer values were larger. Good agreement is found between the observations and simple models of longitudinal dispersion in the lower layer of the Bosphorus.
Mathematical model for soluble carbonaceous substrate biosorption
Authors: Novák Libor , Larrea Luis , Wanner Jiri
Published: May 2018

An activated sludge mathematical model for soluble carbonaceous substrate biosorption has been developed. The model allows the soluble COD fractions in biological reactors of a wastewater treatment plant and/or in batch cultivations to be predicted more precisely than by using conventional models. Special attention was paid to interactions between the biokinetic model structure and population dynamics of microorganisms in activated sludge. The model was developed using observations made on a synthetic wastewater which was dosed to a lab-scale, continuously operated plant with the D-R-D-N configuration. The development of the model advanced through several biokinetic models which resulted in a final version of the biosorption model. The model is constructed on a matrix structure. Adsorption, desorption and hydrolysis kinetics are incorporated into the model. Experimental results from batch cultivations carried out under anoxic and oxic conditions as well as some dynamic tests carried out with the continuously operated system served for the model calibration. Simulations of a wide diversity of kinetic tests demonstrate that the model is able to accurately predict the soluble COD under different cultivation conditions.
Environmental model studies for the Istanbul Master Plan. Part II: water quality and eutrophication
Authors: Bach H. K. , Orhon D. , Jensen O. K. , Hansen I. S.
Published: May 2018

A comprehensive environmental modelling study has been carried out to support the Istanbul Master Plan Study reviewing the waste water strategy for the period up to year 2030, at which time the sewerage system is expected to be extended to serve about 20 million people. Already today the local marine areas suffer from pollution effects caused by sewage discharge. The affected areas in particular are the Bosphorus Strait and the Bosphorus Strait-Sea of Marmara junction area, which are also the natural receiving waters for the sewage from the planned new development areas of Istanbul. The general conditions of the entire Sea of Marmara are also of concern. The object of the study was to determine the effects of the waste water effluent on the marine system and to evaluate alternative plans for sewage treatment and location of outfalls.

An advanced 3-Dimensional model of the Black Sea-Bosphorus Strait-Marmara Sea junction area has been set-up and used for studying the immediate effects on oxygen conditions for a two week long design period. A 3-Dimensional model has been set up for the Sea of Marmara with the purpose of studying the effects of eutrophication over a one year period, which is necessary in order to describe the processes involved. These models are based on SYSTEM 3, a general modelling system for baroclinic flow, including modules describing water quality and biological/eutrophication processes.

The various loading scenarios evaluated included variation in outfall location horizontally and vertically, e.g. in top layer versus halocline or bottom layer trapping and variation in treatment strategy, e.g. no treatment, biological and tertiary treatment.
Some environmental aspects of marine disposal systems with particular reference to UK waters
Authors: Kaya Yusuf
Published: May 2018

Disposal to the marine environment is generally regarded as an effective means of disposing of sewage effluent. In recent years legislation has been introduced to enable marine disposal in a more controlled and environmentally acceptable manner. The discharger must prove to the regulatory authorities that the proposed discharges comply with the relevant legislation.

This paper concentrates on the environmental aspects of marine disposal systems and gives examples from the UK. Emphasis is given to mathematical modelling techniques used to assess compliance with relevant legislation. Data requirements for model set up and calibration are discussed, together with assessment of the level of calibration achieved for two specific coastal applications. An improved representation of wind stress effects on the water column and requirements for a special radiation condition at open boundaries to render the boundary transparent to outgoing transients are also discussed.
Low F/M bulking and scumming: Towards a better understanding by modelling
Authors: Kappeler Jürg , Brodmann René
Published: May 2018

Low F/M bulking and scumming in activated sludge plants is a phenomenon which is not completely understood. Casey et al. hypothesised that low F/M bulking and scumming is caused by the denitrification intermediate nitric oxide. Based on this hypothesis, a mathematical simulation model is formulated which predicts the most important observations related to low F/M bulking and scumming: surfactants and hydrophobic substrates may lead to the proliferation of low F/M filaments, and low F/M bulking and scumming is normally not suppressed by aerobic or small anoxic selectors. Beside these well established facts, the model predicts that incomplete nitrification can cause serious low F/M bulking and scumming problems, that large anoxic selectors with complete denitrification prevent low F/M bulking and scumming and extended sludge blankets in the secondary clarifiers influence the proliferation of low F/M filaments: in completely aerobic systems in a negative way, in systems with predenitrification zones in a positive way.
Ecological monitoring studies for volos sea outfall (Pagassitikos Gulf, western Aegean Sea)
Authors: Theodorou A. J.
Published: May 2018

Nutrient pollution in Pagassitikos Gulf arises mainly from the disposal of Volos untreated domestic wastewater inside Volos Bay, and also the agricultural run-off from the surrounding the Gulf cultivated areas. Volos Bay's limited circulation provides the conditions for the Bay's eutrophication by the discharge of untreated wastewater. In July 1987 this surface discharge was replaced by a new deep outfall system. The latter was located outside Volos Bay discharging primary treated effluents offshore at a depth of 55 m. To monitor any ecological changes, pre-operational (1986-1987) and operational (1988-1989) oceanographic data have been compared. The results showed a decrease in nutrient and phytoplankton concentrations between pre-operational and operational periods. Furthermore, in the vicinity of the present discharge a significant increase in the abundance of benthic communities occurred, due presumably to the continuous supply of food, adequate water circulation and high dissolved oxygen levels.
Marine water quality management in South Africa
Authors: Taljaard Susan , Botes Willem A. M.
Published: May 2018

In South Africa the ultimate goal in water quality management is to keep the water resources suitable for all “beneficial uses”. Beneficial uses provides a basis for the derivation of water quality guidelines, which, for South Africa, are defined in Water quality guidelines for the South African coastal zone (DWAF, 1991). The CSIR has developed a practical approach to marine water quality management, taking into account international trends and local experience, which can be applied to any coastal development with potential influence on water quality. The management plan is divided into three logical components, i.e.

• site-specific statutory requirements and environmental objectives;

• system design with specific reference to influences on water quality; and

• monitoring programmes.

Within this management approach water quality issues are addressed in a holistic manner, through focused procedures and clear identification of information requirements. This paper describes the procedures and information requirements within each component of the water quality management plan, with specific reference to marine disposal systems. Ideally, the management plan should be implemented from the feasibility and conceptual design phase of a development and the timing of the different procedures within the development process are therefore also highlighted. However, the logical lay-out of procedures allows for easy initiation (even to existing disposal system) at any stage of development.
A pilot study of vertical flow wetlands at coffs harbour, New South Wales, Australia
Authors: Chick A. J. , Mitchell D. S.
Published: May 2018

A modular series of vertical flow wetland (VFW) systems was established in 1989/90 to treat up to 130,000 litres per day of primary settled sewage on the north coast of New South Wales, Australia as an experimental scale-up of wetland microcosms that had been developed with this hydrological format. Monitoring of inflow and outflow water quality was maintained on a weekly basis from January 1991 to February 1992. Some management parameters (e.g. flow rates) were varied during this period. Dye injection to examine hydraulic behaviour within the gravel bed was carried out on two occasions in one VFW. In general the removal of nutrients was lower than expected, with between 20% and 40% reduction in concentrations and removal of loads over the year. Suspended solids and BOD removals were excellent, with a surprisingly good reduction in faecal coliform counts as well. Reduction in flow rates improved performance markedly in all parameters.
Nutrient partitioning in a clay-based surface flow wetland
Authors: Adcock P. W. , Ryan G. L. , Osborne P. L.
Published: May 2018

A constructed, clay-based, surface flow wetland located in Byron Bay, New South Wales, Australia, was studied to determine the relative importance of living plant tissue, plant litter, sediment, and the water column as nutrient stores. The nitrogen, phosphorus and carbon contents of each nutrient compartment were determined throughout the wetland. The nitrogen and phosphorus content of the plants was higher at the inlet end of the wetland and declined with distance away from it. Nutrient levels in the sediment and water column did not vary significantly with distance through the wetland. Phosphorus concentrations in the sediments were high, but plants were shown to be responsible for the majority of nutrient accumulation from this system. The plants had failed to penetrate the clay substrate and a solid mat of adventitious roots had developed in the overlying water. In essence the plants, mainly grasses, were growing hydroponically.
Removal of pathogens from wastewaters by the root zone method (RZM)
Authors: Rivera Fermin , Warren Alan , Ramirez Elizabeth , Decamp Olivier , Bonilla Patricia , Gallegos Elvia , Calderón Arturo , Sánchez José Trinidad
Published: May 2018

Full-scale and laboratory-scale artificially constructed reed beds utilising the root zone method (RZM) of wastewater treatment were investigated for their removal efficiencies of a range of pathogenic microorganisms. Performances were compared for RZMs employing different hydrophytes, planting substrates and climatic conditions. All pathogens were removed by the RZM to some extent. Planted beds generally performed better than unplanted beds although the type of hydrophyte used was not significant. Gravel beds were more efficient than soil beds in the removal of protozoan pathogens and of helminth eggs; numbers of these pathogens were below levels of detection in gravel bed effluents. For faecal coliforms the type of planting substrate was not significant, providing hydrophytes were present. Climatic conditions made little difference to treatment efficiency although seasonal variation was observed in temperature climates, where the removal of faecal coliforms declined in the winter months, and in subtropical climates where higher numbers of free-living amoebae were recorded during the summer. It was concluded that the RZM is a suitable method for the treatment of domestic wastewaters in tropical and subtropical regions of Mexico.
A study of activated sludge dewatering in experimental reed-planted or unplanted sludge drying beds
Authors: Liénard A. , Duchène Ph. , Gorini D.
Published: May 2018

The study was performed over the period from June 1989 to December 1992 on 3 experimental concrete beds of 20 m2 each, constructed close to an extended aeration plant. Beds 1 and 2 were planted with reeds, bed 3 was considered as an unplanted control bed. During the first phase (June 89-May 90), most of the reeds in bed 2 died in spite of the influent sludge dose of 70 g of SS m−2 d−1. During the second phase (917 days) the 3 beds were naturally aerated from the bottom and fed with sludge that was directly extracted from the oxidation ditch (Dry Matter content 0.3%). The influent sludge load varied between 120 and 160 g of SS m−2 d−1 after the second growth season (with peak values of up to 215 g of SS m−2 d−1 in the summer of 1991). Even if bed 3 didn’t clog, the major contribution of the reeds to maintaining a high and regular liquid conductivity in the sludge has been proven, allowing easier and higher dosing of the planted beds. Monitoring of the percolation flow emphasised a high mineralization process in the rhizosphere. The accumulated sludge (Total Solids content ≈ 11%) can be dug out together with the reeds using a mechanical digger and spread on fields with a manure spreader. A regrowth of reeds occurs directly from rhizomes remaining in the drainage layer and in a few centimetres of sludge at the bottom of the bed.
Rootzone dynamics in constructed wetlands receiving wastewater: a comparison of vertical and horizontal flow systems
Authors: Breen Peter F. , Chick Alan J.
Published: May 2018

Profile conditions were examined in both small experimental and pilot scale sub-surface flow wetlands. The study systems differed in their hydraulic design. The experimental systems had a vertical up-flow design whereas the pilot system was a horizontal flow trench design. Both systems were found to have significant physical, chemical and biological gradients within the sub-surface profile. System age and plant root density appear to be important factors in determining profile differentiation within the experimental systems. Root densities were found to be partitioned between the upper and lower layers on a 70%/30% split, respectively. However, in the experimental systems as the systems aged and root densities increased beyond 112-251 g.m−2 chemical water quality differentiation in the profile disappeared. Pilot scale systems were found to have physical gradients within the profile as evidenced by hydraulic short-circuiting. Vertical root density distribution is proposed as a major cause of this condition in horizontal flow systems.
Reed bed treatment systems for sewage treatment in the United Kingdom - the first 10 years’ experience
Authors: Cooper P. , Green B.
Published: May 2018

The UK Water Industry first became interested in Reed Bed Treatment Systems for sewage in 1985. Early problems were experienced with soil-based horizontal-flow systems of the Root Zone type. The problems were overcome by national co-ordination of a development programme and international co-operation by an EC Expert Contact Group. A number of different types of systems have now been developed and the systems are now being accepted. The paper reviews the development of these systems for secondary and tertiary treatment and nitrification and mentions development of systems for other forms of treatment. The design changes made to overcome the problems are described. These include the gradual move to the use of gravel-based systems because of the difficulty experienced with over-land flow in the soil systems. The sizing of the systems is described together with performance data for the original horizontal-flow and the more recently developed vertical-flow systems. Treatment at secondary and tertiary levels is illustrated and the potential for nitrification. Early problems with reed growth have been overcome by planting with port-grown seedlings.

After 10 years the process is generally accepted by the Water Industry as an appropriate treatment for villages and there are now between 200 and 300 systems in operation.
Cyanobacterial toxins: occurrence, properties and biological significance
Authors: Codd G. A.
Published: May 2018

All of the most commonly encountered genera of cyanobacteria which form blooms and scums in fresh-brackish- and marine waters include members capable of producing potent toxins.

Poisonings of vertebrate and invertebrate animals following the ingestion of cyanobacterial bloom/scum material have been widely reported for many years and recognition of the adverse effects of cyanobacterial blooms and their toxins is increasing. This review considers the occurrence of toxic cyanobacterial populations and properties of the toxins themselves, of which at least 60 are now recognised. When rightfully regarded as microbial secondary metabolites, a range of possible functions for cyanobacterial toxins is presented. Whether cyanobacterial toxins contribute to the ability of cyanobacteria to dominate many eutrophic waterbodies is unknown, although understanding of the occurrence of the toxins in aquatic environments and their actions at the molecular level and with whole organisms in laboratory studies indicates that this is possible.
Microcystin-content, hepatotoxicity and cytotoxicity of cyanobacteria in some german water bodies
Authors: Fastner Jutta , Heinze Rita , Chorus Ingrid
Published: May 2018

In 1993 12 eutrophic waterbodies and four laboratory strains were examined for their content of microcystins. In addition to chemical analysis toxicity was assessed with bioassays: primary rat hepatocytes for testing hepatotoxicity and a CHO-K1 cell line for determining more unspecific cytotoxicity. Altogether nine of twelve waterbodies and two laboratory strains contained up to seven different microcystins and were hepatotoxic. Cytotoxicity was observed in six of 24 field samples and one of four laboratory strains. Pure microcystin-LR has an EC50 of 0.2 μg/ml, microcystin-YR of 0.35 μg/ml and microcystin-RR of 4.5 μg/ml on primary rat hepatocytes but showed no further cytotoxicity. Hepatotoxicity was always significantly higher than can be explained by their content of microcystins. Probably other substances from the algae or their environment cause reactions which are synergistic with or additive to microcystins.
The effect of organic reactions in a collection system on wastewater treatment plant performance
Authors: Gall Bruce , Takács Imre , Patry Gilles
Published: May 2018

Biological reactions within the sewer play an important role in establishing the water quality characteristics of combined sewer overflow and of the sewage entering a wastewater treatment plant. A simulation model that shows the effects of reactions in the collection system on wastewater treatment plant performance has been developed. A series of numerical experiments was conducted to illustrate the features of the model, and the potential benefits of the approach. The study also serves to identify areas in which the models need to be improved.
Mousetrap: modelling of real sewer sediment characteristics and attached pollutants
Authors: Crabtree R. W. , Ashley R. , Gent R.
Published: May 2018

A dynamic, pollutograph based sewer flow quality simulation model is an essential tool to aid in the control of intermittent pollution from combined sewer overflows (CSOs). Such a model can be used in conjunction with river impact models to provide an objective methodology for the control of intermittent sewage discharges. A new component to the MOUSE package has been developed, called MOUSETRAP, which is composed of a series of deterministic modules to represent the quality of surface run-off, sediment and pollutant transport within the pipe network, and the biological and chemical reactions within the sewer system. MOUSETRAP can be used to predict sewer flow quality and, hence, CSO spill concentrations and loads over time.

The results of recent research into the behaviour of sediments and associated pollutants in sewers have shown that these aspects are crucial to the development of a reliable, deterministic sewer flow quality model. MOUSETRAP, by representing the physical and chemical characteristics and behaviour of real sewer sediment types has the ability to simulate storm event pollutographs incorporating first foul flush phenomena. MOUSETRAP achieves this by representing pollutants associated with dissolved phase liquid transport and pollutants associated with sediments including bed deposits, bed load and settleable suspended solids.

The results of data collection are used to characterise sewer sediments and a theoretical basis for the modelling of sediments and sediment attached pollutants in MOUSETRAP is considered. Finally, the model default values for characteristics of the surface, deposited foul flow and in-pipe sediment types in MOUSETRAP are presented.
Tsunami vulnerability modelling for the Bulgarian Black Sea coast
Authors: Ranguelov Boyko , Gospodinov Dragomir
Published: May 2018

The problem of tsunami hazard assessment and water pollution appear during the last years in connection with the increased density of infrastructure and industrial facilities on the Black Sea coast. The paper deals with the main results of the tsunami vulnerability modelling in accordance with the internationally recognised methods and new data obtained during the last years. Data collection, new approaches for travel times and dynamic properties of the giant sea waves have been investigated in the previous research. Now the main tsunamigenic sources together with the most vulnerable areas are outlined on the Bulgarian part of the coast. Together with the tsunami energy distribution according to the new method of ray tracing and refraction, the results give the possibility to establish the concentration-dissipation areas, which are most important to the tsunami risk assessment.
The transfer of solids in combined sewer networks
Authors: Chebbo G. , Bachoc A. , Laplace D. , Le Guennec B.
Published: May 2018

Suspended solids are the main vectors of pollution in combined sewer wet weather flows. In spite of being very fine, they decant rather quickly except in the case of light rainfall events rich in organic matter. The part originating from sewer sediment deposits provides a large proportion of organic matter mass. By analysing the content and the volume of sewer deposits at different points from upstream to downstream, it emerges that the main source of this contribution is probably located in man-entry sewers. In one of these, sewer trunk no. 13 in Marseilles, five hundred metres of which were monitored continuously for sediment build-up over three years, the deposit volume grows mainly during certain rainfall events and its surface slope tends to an equilibrium with the (millimetric) particle size. Theoretical bed-load and suspension thresholds have been validated, then analysed for various situations and sections. A typology of the vulnerable areas, in several networks, has been drawn up, as well as a study of shear stress variations during a rainfall event. The sediment deposits seem to occur in particular hydraulic discontinuity zones where transport capacities can drop sharply.
Oxygen transfer in gravity flow sewers
Authors: Balmér P. , Tagizadeh-Nasser M.
Published: May 2018

Oxygen transfer to water in gravity flow pipes has been studied in a 24 m long, 0.225 m diameter sewer. Laboratory tests were conducted where the slope and flow in the sewer could be varied independently. The clean water reaeration test was used to determine the oxygen transfer. The KL value for the oxygen transfer was found to be a function of energy dissipation and mean hydraulic depth. The results are discussed in relation to oxygen transfer determinations in flumes and field studies of oxygen transfer in sewers.