bluuebunny/crossref_metadata_2025 huggingface dataset:
Ecology and the Zuiderzeeproject
Authors: de Jong J , Roelofs J H
Published: May 2018

The former Zuiderzee, a large estuarne area over 500,000 ha located in the northwestern part of the Netherlands has undergone great changes due to the execution of the Zuiderzeeproject.

Within the framework of this project 375.000 ha of the area has been dammed and excluded from the influence of the sea. The waters in the area were turned into stagnant, eutrophic freshwaters by using the water from the river IJssel. In the dammed off region also four polders, having a total area of 165,000 ha have been reclaimed. A fifth polder of 41,000 ha is planned, but not yet decided upon.

The execution of this project was started in 1919 and is still not yet finished.

In the beginning of the execution of the project, due to the social and economic conditions of that time, only limited attention has been paid to ecological expects of the project during planning, execution and initial management. However the ecological changes that would occur were regarded to be very important from a scientific point if view. As a result both the original situation and the changes in the aquatic ecosystem have been monitored. Also transient high ecological values of the new polders have been well documented by the scientists. As a result when social and economic conditions changed after the second world war and especially in the period after about 1965 a sound basis of biological and ecological knowledge was present and incorporated in the state authorities invloved to enable the additions of ecological considerations into the development of both polders and lakes.

Due to the flexibility of the Zuiderzee project where the project is excecuted polder after polder in the two polders that have been made after the second world war large areas of forest and nature reserves have been realized next to other means of land use such as agriculture, infrastructure, recreation and urbanization.

By this way changing views of society reflect upon the way of development and management of both land and lakes.

Nowadays both lakes and polders provide on a international level high ecological values, especially for birds, in spite of drastic ecological changes.

A careful planning, excaition and management by state organizations, assisted by continuous research, prove to be essential factors to realize these results.
Environmental and Nature Conservation Aspects of Tidal Power Proposals for the Severn Estuary (UK)
Authors: Mitchell R , Probert P K
Published: May 2018

Recent studies of tidal power generation in the Severn Estuary indicate that a single basin ebb-generation scheme would produce marked changes in the physical and chemical environment. The impact of these factors on the natural environment is reviewed. Implications for the particular features of nature conservation interest of this important estuarine area are examined and the opportunities for the amelioration of deleterious effects are discussed.
Simulation of Ecological Impacts of the New Outer-Harbour Development in Zeebrugge
Authors: Roovers P , Ozer J , Mommaerts J P , Adam Y
Published: May 2018

The new outer-harbour in Zeebrugge is to be protected by jetties extending 1,750 m seaward. This development will alter the local distribution of tidal and residual currents. Such hydrodynamic changes will, in turn, affect the dispersion pattern of dissolved and particular matters in the vicinity of Zeebrugge. A mathematical model is presented, which simulates the dispersion - before and after outer harbour development - of dissolved organic matters, faecal bacteria and heavy metals, which are indicative of, respectively domestic, human, and industrial pollutions.
The Environmental Effects of Flood Control in the Yare Basin
Authors: Wakeling H L
Published: May 2018

The paper reviews various methods of flood control in the lower Yare Basin which has been subject to serious flooding caused by storm surges in the North Sea and by fluvial floods. This area is known as the Broads and is an area of scenic beauty, includes many sites of scientific interest and is a popular tourist area.

The effects of the different flood control options on the environment are discussed. The primary economic justification for flood prevention was found to arise from the conversion of poor quality marsh grazing land to arable or improved pasture once the risk of saline flooding was removed. The consequences of this change in land use on the flora and fauna have aroused much concern among environmentalists.
Bolsa Chica – A Case Study in the Reconciliation of Social and Ecological Concerns Involving the California Coast
Authors: Fisher Robert G , Marsh Lindell L
Published: May 2018

The effort to reconcile the many conflicting possible uses (oil production, housing, wildlife habitat and recreation) of the Bolsa Chica Area by the various governmental agencies and public and private sector interests involved in the planning process provides a valuable case study of developing California planning and regulatory procedures to integrate ecological concerns into major coastal projects. The thrust of the consensus planning approach is a joint venture formed early in the planning process between the public and private sectors to resolve conflicting interests by providing a trusted forum to develop the necessary information and determine the decision-making procedures.
U.S. Army Coastal Engineering Research Center's Ecology Program
Authors: Pullen E J , Knutson P L , Hurme A K
Published: May 2018

The Coastal Engineering Research Center at Fort Belvoir, Virginia, is responsible for research that supports the U.S. Army Corps of Engineers' Civil Works program. This research involves coastal navigation, channel design and maintenance, storm flooding, shore erosion control, and coastal ecology. The ecology research is focused on two major areas: (1) use of coastal vegetation for engineering purposes and (2) effects of coastal engineering activities on the biological environment. The objectives and accomplishments of the ecology research are discussed and specific examples of field guidance are presented.
Multiobjective Coastal Planning via Measurable Value Optimization
Authors: Lee William W-L
Published: May 2018

Measurable value optimization is suggested as a method of integrating ecological concerns into the planning and management of offshore sand and gravel mining.
Integration of Interfaces of Coastal Systems and Technology in Coastal Zone Management
Authors: Lakshminarayana J S S
Published: May 2018

This paper identifies and presents some examples of case studies of coastal zone engineering projects of the Atlantic Provinces, Canada, and discusses the interplay between the ecological aspects of the coastal systems in relation to engineering management. It focuses on the urgency of public involvement in the shore area problem-solving and points out the political sensitivities inherent in environmental and resource management problems. To illustrate the need for research to arrive at proper solutions, an example is presented on the Caraquet Bay, New Brunswick, Canada. Basic research is needed to understand the functioning of the coastal zone. Baseline studies will make a beginning by documenting the present environmental health of the coastal zone.
Past and Pending Decisions Controlling San Francisco Bay and Delta
Authors: Davoren W T , Ayres J E
Published: May 2018

Over the past 130 years, the largest inland estuary of America's west coast, the San Francisco Bay and Delta,1 has been altered greatly by land and water development. To the detriment of estuarine processes and indicator species, upstream impoundments, diversions and pumped exports from the Delta have reduced river flows by 50 percent or more. Long-term effects of the upstream impoundments and removals are just beginning to be understood. Additional storage and diversion units are planned. The responsibility for repelling salinity intrusion from the Bay to the Delta's waters is not clearly defined. Additionally, drainage projects are underway to transport land-derived salts from inland irrigated areas for discharge into the Bay's headwaters. Also, the threat of levee collapse in the Delta from erosion and subsidence advances yearly. Navigation, agriculture, recreation and fish/wildlife needs further complicate land and water management challenges in the Delta. This paper appraises the present realities produced by past projects and policies.

1Delta is used throughout as a California place name that applies to the combined areas of the Sacramento and San Joaquin River deltas (Fig. 2). The Bay begins at Chipps Island, just below the confluence of the two rivers, and extends to Golden Gate on the west and San Jose on the south (Fig. 1).
Unesco Programme Activities in the Coastal Zone
Authors: Steyaert M , Troost D G
Published: May 2018

The spectrum of Unesco's activities as concerns the coastal zone covers a wide range of aspects. These activities are grouped in a number of programmes and projects. Brief descriptions of the main activities, both those funded by Unesco itself and those executed by Unesco but funded from external sources, are presented. Reference is made to the programme on “Management of coastal and island regions” in the Unesco Medium-Term Plan for the period 1984-1989.
Costs and Benefits of Estuarine and Coastal Pollution Control
Authors: Roberts D G M , Holmes P G
Published: May 2018

The background to estuarine and coastal water pollution control is described and the various costs and benefits associated with improvement measures are examined. Comparative costs associated with different engineering solutions are considered with reference to particular examples.
The Effects of the Yorkshire Rivers on Dissolved Oxygen in the Humber Estuary
Authors: Edwards A M C , Lai P W
Published: May 2018

The tidal rivers of the Humber Estuary System experience depletion of dissolved oxygen in dry, summer weather as a result of the pollution received from effluent discharges and the rivers of industrial Yorkshire. A suite of mathematical models has been developed to predict dissolved oxygen saturation and the concentration of related substances. Computer simulations using the models have been carried out to assess the effects of freshwater flow and oxidisable pollutants on dissolved oxygen levels in the estuary system. The models provide a practicable, water quality management tool for the Humber Estuary.
Operational River Water Quality Management
Authors: Jowitt P W , Lumbers J P , Beck M B , Jenkins W O
Published: May 2018

The developments in water pollution control legislation and their interpretation are discussed in the context of the current need to establish flexible operational control hierarchies reflecting conflicting uses of surface waters and overall basin economy. Fussy logic is proposed as a technique to aid the reconciliation of within-plant and within-receiving water operational targets with the consistent interpretation of statutory requirements. An example simulation of the control of a waste-water treatment plant to meet time-varying river water quality objectives is presented in support of the argument.
Modelling the Seasonal Variation in Structural Biological Components and Oxygen in Macrophyte Dominated Streams: A Summary of Work in Progress
Authors: Jeppesen E , Thyssen N
Published: May 2018

In this paper we summarize the results obtained from 4 years study of the oxygen dynamics of small, macrophyte dominated low-land streams in Denmark. We describe the development of models for the important biological components, that is macrophytes, sediment organic matter and chlorophyll-a, and discuss the coupling of these models to models for biological and physical processes affecting the oxygen concentration in the stream.
Risk Analysis, Fuzzy Logic and River Basin Management
Authors: Jowitt P W
Published: May 2018

The link between the need for operational control and the mathematical modelling of badly-defined environmental systems is examined. It is argued that the robustness of process models and control measures is more important than their sophistication. Because of the nature of such systems, control robustness can be effected in many cases through the exercise of experience and acquired expertise, formalised through expert systems and fuzzy set theory. It is argued that for the same reason, there is a duality between control and system identification and that classical identification methods should be tempered by the application of fuzzy sets and expert systems theory.
Modelling Nitrate and Algal Behaviour in the River Thames
Authors: Whitehead P G , Williams R J
Published: May 2018

As part of a collaborative project with Thames Water Authority a multi-reach, multi-tributary flow and quality model has been developed for the Thames River System. Nitrate and Algal models have been developed using routinely collected water authority data. The models are being used to investigate design and operational management problems within the Thames River basin.
Effects of Biological Films on BOD Decay Rates in Rivers
Authors: Boyle J D
Published: May 2018

The measured dissolved oxygen sag below a paper-mill outfall could only be modelled if the BOD decay rate was assumed to be an order of magnitude greater than expected. Subsequently other cases of anomalously high decay rates have been found. A method was developed for measuring the separate factors of bacterial respiration and photosynthesis by attached and suspended organisms. Results confirmed that the decay rate is enhanced by the presence of an active biological film covering submerged surfaces. The prediction of decay rates in similar circumstances is complicated by two factors, the estimation of the active film surface area and the dependence of the film activity on both nutrient concentration and water velocity. The paper relates these phenomena to laboratory studies and shows how these factors affect the predictions of management models.
Rainfall Events as Paths of a Stochastic Process: Problems of Design Storm Analysis
Authors: Brummer Johannes
Published: May 2018

Problems in the construction of design storms are expressed in mathematical terms. Introduced here is a concept for approximating natural peak flow values by means of the distribution of typical rainfall patterns. A comparison demonstrates the quality of this concept and the competency of some well-known design storms for the adequate evaluation of peak flows.
Temporal Distribution of Design Storm Rainfall
Authors: Marsalek J
Published: May 2018

Basic characteristics of urban design storms are presented and discussed. One of these characteristics, the temporal rainfall distribution, is further examined by demonstrating its effect on simulated runoff peaks and by comparing various distributions found in the literature. General comparisons of temporal distributions indicate large differences among various distributions. Further comparative studies and exchange of experience are recommended.
Design Inflow Intensity and Design Inflow Profiles for Storm Sewers
Authors: van de Ven Frans H M
Published: May 2018

Twelve year records of rainfall and of sewer inflow data in a housing area and in a parking lot in Lelystad were available. These data series contained 5-minute depths of rainfall and sewer inflow. Depth-duration-frequency curves were calculated from the monthly extremes, using Box-Cox transformation and a Gumbel distribution. The differences between the curves for rainfall and for inflow are explained by inertia and rainfall losses. These differences are the reason to use inflow as a sewer design parameter. Forthe choice of the design discharge (or inflow) intensity the curves are not well suited. Storage-design,discharge-frequency curves proved to be better interprétable. The selected design discharge is 4 or 5 m3/s/km2. For non-steady flow calculations in sewer systems an inflow profile has to be provided. The prof ileshould be peaked. The most common location of the peak lies between 20 and 50% of the event duration. The return period of the profile has to be known. A bivariate extreme value distribution is used to estimate this return period. From these distributions synthetic inflow profiles could be calculated.
Potential Urban Rainfall Prediction Measurement System
Authors: Vogel John L
Published: May 2018

Continued growth of urban regions and more stringent water quality regulations have resulted in an increased need for more real-time information about past, present, and future patterns and intensities of precipitation. Detailed, real-time information about precipitation can be obtained using radar and raingages for monitoring and prediction of precipitation amounts. The philosophy and the requirements for the development of real-time radar prediction-monitoring systems are described for climatic region similar to the Midwest of the united States. General data analysis and interpretation techniques associated with rainfall from convective storm systems are presented.
Studies on the Causes and Prevention of Bulking Sludge in Germany
Authors: Wagner F.
Published: May 2018

The development of bulking sludge causes operational problems in about half of the activated sludge plants. Investigations in Germany describing a large number of industrial and operational parameters from more than 100 activated sludge plants, as well as technical research on prevention and control measures, contribute to an understanding of this problem and give information about possible causes and means to prevent bulking sludge.
Settling Properties of Activated Sludge Related to Floc Structure
Authors: Eriksson L , Härdin A.-M
Published: May 2018

When characterizing sludge settling by means of sludge volume index and stirred sludge volume index it has been found that the former is normally higher, but that the difference varies greatly for different sludges. It was found to depend on difference in shape of the flocs. Spherical flocs give small differences and elongated flocs give large ones. Although both indices were positively correlated to the total length of filamentous organisms the differences were not.

A general floc model is proposed on the basis of these findings together with colloid chemical considerations and measurements of floc strength, filtration resistance and amount of extracellular polymers. According to this model young flocs are of the elongated type, while flocs from a stable system are round. Sludge bulking is a consequence of stiff noncompressible flocs which may be due to high amounts of dissolved polymers, but most likely to filamentous organisms fixed in a network by binding polymers within the flocs. The amount of filaments inside the flocs is probably proportional to the amount outside which for that reason is correlated to the settling indices.
A Combination of the Activated Sludge Process with Fixed Film Biomass to Increase the Capacity of Waste Water Treatment Plants
Authors: Hegemann W
Published: May 2018

The volume of the activated sludge aeration tank is influenced by f/m ratio and attainable biomass concentration. Increase of biomass results in smaller tank volume. In case of overloaded plants restoration may be achieved by increase of biomass instead of construction of further tank volume. Pieces of porous plastic media filled into ordinary compressed air aeration tanks may serve as fixed film biomass support. By this method biomass concentration in the tank may be increased to two or three times normal values. At the same time the sludge volume index of the activated sludge flocs still present in the aeration tank is improved. Better sedimentation and thickening of the activated sludge occurs because smaller quantities of flocs are passed to the final clarifiers.

Results of tests with different types of waste water in semi-technical scale pilot plants as well as in existing plants of different sizes are presented.
Full Scale Experience with Tertiary Contact Filtration
Authors: Boller M
Published: May 2018

The first full-scale contact filtration plant for advanced phosphorus removal in Switzerland was built 1979. In a twelve month investigation, the following design and operational aspects were considered: optimal chemical conditions for phosphorus removal, multimedia filter configuration, long-term performance of the total process combination (which included conventional treatment with simultaneous precipitation and contact filtration), and operating variables as filtration velocity, filter run time and backwash water use. Under optimal conditions, contact filtration provided consistently low phosphorus and suspended solids levels at reasonable cost.
Observations on Final Sedimentation at Vienna's Main Treatment Plant, Austria
Authors: Fleckseder H , Fruhwirth D
Published: May 2018

Despite the shallow tank depth (2,3 m) and high hydraulic surface loading (at design flow, 1,0 m3 m−2h−1), solid - liquid separation at Vienna-Simmering seems to be good. This was the reason that an investigation was started into the behaviour of the final sedimentation tanks at Vienna-Simmering. The work performed centered around the question of mass transport of mixed liquor into and out of final clarifiers, i.e. the transport in thickening, intermittent sludge collection (with scraper blades) and the mass balance around final tanks. Looking upon the findings and published information, it seems that the importance of mass transport of sludge in collection and flow out of tank has been somewhat neglected.
Forest Industry Anaerobic Wastewater Treatment and its Future Development
Authors: Orivuori Juhani
Published: May 2018

Very few methods have been developed with such speed as anaerobic wastewater treatment. Universities, Government agencies, private enterprise and scientists all over the world are using millions of dollars in studies, pilot and full scale experiments trying to find the most practical anaerobic treatment systems for various wastewaters. The follow-up alone of all the information published in this field would require an institute of its own. Commercial interests are driving private enterprise to fast development of full scale treatment plants.

In this paper the reasons for this interest in anaerobic treatment are focused on in the light of the recent developments in knowledge of the quality and quantity of forest industry wastewaters. Future wastewater characteristics and the possibility of anaerobic treatment to meet future demands are discussed. The need for co-operation between forest industry process engineers and wastewater treatment specialists is emphasized in order to optimize internal and external pollution control methods.
Transport of Solutes in Soil: Basic Features of Front Retardation
Authors: Bolt G. H.
Published: May 2018

Application of the integral conservation equation to a moving concentration front provides the basis for calculation of its mean rate of movement. Doing so shows that the simultaneous presence of different adsorbates exhibiting differing adsorption isotherms leads to the formation of a corresponding number of concentration fronts separated by a transition region. It is shown that in this region concentration levels in excess of those occurring in both the feed solution and in the initial solution phase are characteristic. A similar reasoning applies to the situation where an incoming solute in the mobile solution phase is subject to the formation of a precipitate with an ion driven off the solid phase by an also incoming competitor for adsorption sites on the solid phase. Then again excessive concentration levels are shown to arise occasionally in the transition zone between the precipitation and dissolution fronts. Finally the effect of a delayed equilibration between the mobile and an immobile (adsorbing) phase is discussed briefly.
The Mobilization of Heavy Metals in River Sediment by Nitrilotriacetic Acid (NTA)
Authors: Loch J P. G. , Lagas P.
Published: May 2018

The mobilization of heavy metals in river water and sediment by NTA during river bank filtration was investigated in the laboratory under oxygen-deficient conditions. Four PVC-columns, 1.20 m long, 0.18 m diameter, filled with river bed sediment, were percolated for 7 months with river water spiked with NTA. Water and sediment were collected from a branch of the river Rhine, where the sediment has high metal contents. The percolation rate was 10 cm. day−1. Supply water for three columns was kept oxygen-deficient. Water for the fourth column had an oxygen content of 6 mg.dm−3. To the anoxic river water NTA was added to concentrations of 0, 100 and 600 µg.dm−3 respectively. The oxic water obtained an NTA-concentration of 100 µg/l. Leachate and pore water were analysed for heavy metals, inorganic macroparameters and NTA. After percolation the sediment was analysed for bound metals. When river water and sediment contained adapted micro-organisms, NTA was degraded within two weeks in all columns. Degradation was nearly absent during the first three weeks of percolation, due to the necessary adaptation. Except for the first month, NTA was not detected in the pore water below 10-30 cm. In the first month it penetrated into the leachate. Within the concentration range considered, neither NTA- nor O2-content of the supply water affected the mobilization of the heavy metals considered.
Distribution of Metal Pollution in Groundwater Determined from Sump Sludges in Wells
Authors: Hoehn Eduard , von Gunten Hans R.
Published: May 2018

Sludge material from the bottom of ground water sampling wells was investigated at a site near an infiltrating river in order to obtain information about the areal distribution and the partitioning of metals between sediments and interstitial waters. The concentrations of the dissolved metals in the interstitial water fluctuated more from well to well than the metal concentrations in the sludge sediments. The concentrations of most of the investigated heavy metal trace elements decreased with increasing grain sizes indicating their sorption from solution. A correlation was found between the concentration pattern at different grain size fractions and the organic carbon and the manganese content of the sediments. Some of the metals exhibited higher concentrations in the near field of the river than in the far field. This points to the river as a source for these metals. The physico-chemical conditions in the sludges are different from those in the aquifer with its flowing ground water.
Electrofocusing of Viruses and Sensitivity to Disinfection
Authors: Butler M. , Medien A. R. , Taylor G. R.
Published: May 2018

Viruses have individual and characteristic isoelectric points and for poliovirus there was good evidence for a correlation between one of these and sensitivity to chlorine. However, in the presence of chlorine dioxide, bromine chloride and iodine the behaviour of poliovirus and f2 coliphage was similar and not apparently influenced by the isoelectric point.
Mixing and Detention Time Distribution in Activated Sludge Tanks
Authors: Bode H. , Seyfried C. F.
Published: May 2018

The interrelationship between mixing characteristics and tracer response curves in activated sludge tanks is explained. In some cases the return sludge cycle has a strong influence on the tracer response curves. Results from tracer tests in the field are hard to interpret because the tracer in the return sludge interferes with the initial tracer. Therefore a special evaluation procedure has to be applied. The paper closes with results from a field tracer test study.
Sludge Treatment Technology and Ionizing Radiation
Authors: Sedláček M. , Koubík M. , Vacek K. , Rejholec J.
Published: May 2018

The application of radiation hygienization of sludges in sewage works can be affected by secondary effects of this process. The change of the colloidal system of liquid sludges by irradiation results in an improvement of their thickening capacity, but at the same time produces an increase in the demand for polymer flocculants for the conditioning of sludges prior to their dewatering. The irradiation dose of 3 kGy decreases the concentration of Salmonella senf. by at least 6 orders, and at the same time the reinfection of the sludges by prolonged storage is suppressed. Two years of field tests showed higher potato and barley yields with irradiated sludges compared with non-irradiated sludges. The economic evaluation demonstrated under Czechoslovak conditions the suitability of the use of electron accelerators as radiation sources and the introduction of ionizing radiation behind the mechanical sludge dewatering process.
Sludge Stabilisation and Disinfection by Means of Autothermal Aerobic Digestion with Oxygen
Authors: Trim B. C. , McGlashan J. E.
Published: May 2018

Research at pilot-scale was undertaken into autothermal aerobic digestion of sludge using oxygen to demonstrate that sufficiently high temperatures can be achieved to ensure the degree of disinfection that would satisfy the health authorities. The ova of the helminth Ascaris lumbricoides were used in the disinfection studies and the dissolved oxygen level in the sludge was used as a means of controlling oxygen consumption.

The results achieved indicate that the system very rapidly attained a stable temperature which could be easily maintained and which effectively ensured disinfection of the sludge at the 2 and 4 day retention periods tested, that the treated sludge readily ferments anaerobically, that the sludge will not readily settle and is very difficult to dewater.
Sunlight Photooxidation of Organic Pollutants in Wastewater
Authors: Acher A. J.
Published: May 2018

The material presented represents results of a research on a new method for using solar energy for municipal and industrial wastewater treatment. This research seeks to develop economical methods of disinfection and detoxification of wastewaters which would result in the reuse of effluents for crop irrigation.

Aerated effluents containing dye-sensitizers were exposed to solar irradiation for various periods of time. The influence of the solar energy, absorbed by these sensitizers in the visible range, on the organic matter and anionic surfactants in secondary effluents was checked by determining the COD and MBAS values of treated wastewater.

The disinfection potential of this method was followed by bacteriological analyses of running water or secondary effluents, previously contaminated or enriched, respectively, with laboratory cultures of E. coli, bacteriophages (coliphage X and F2) and polio virus (type L-Sc 1).

The influence of this photooxidative method was also studied in eutrophic algae present in the Lake of Galilee. It was found that the conditions under which disinfection proceeds also support algicidal processes, causing lethal damage to algal cultures.

Further investigations on stable pesticides (uracil, s-triazine and anilide derivatives) in surface water or industrial wastewater showed that such a method can also be used for detoxifying pesticides in these waters.
Synthesis Modeling of Municipal Wastewater Treatment Systems
Authors: Câmara A. S. , Randall C. W. , Frair L. C.
Published: May 2018

The synthesis of wastewater treatment systems refers to the specification of both a system structure–the choice and arrangement of unit processes and operations–and the design of the individual units within that structure so that a set of economic and environmental objectives is fulfilled. This paper shows that one can not yet develop optimal synthesis models due to limitations on cost and engineering data used as input in those models.

It is illustrated however that a rational synthesis modeling effort offers two important contributions: the development of an improved although still sub-optimal version of a wastewater treatment synthesis model; and the systematic identification of research areas to be followed if one wants to overcome the limitations above mentioned and thus enable the development of a model to guide a truly optimal design of wastewater treatment systems.
Mechanism and Kinetics of Cementation Processes
Authors: Khudenko Boris Mikhail
Published: May 2018

The physics of cementation processes (metal displacement) have been analyzed. An important effect of the intermediate species, hydrogen, H+, and hydride, H−, on the mechanism of cementation has been shown. The possibility of either diffusional or migrational (electric current) transport of active species has been suggested. A kinetic model of the cementation migration regime has been developed and partially verified by experimental data.
The Role of Phytoplankton in the Dissolved Oxygen Budget of a Stratified Estuary
Authors: Soulsby P. G. , Mollowney M. , Marsh G. , Lowthion D.
Published: May 2018

Observations of dissolved oxygen in the Test Estuary, Southern England have shown lowest levels following a mid summer phytoplankton bloom. The bloom was dominated by the ciliate Mesodinium rubrum (Lohmann). A numerical model has been developed to calculate the water circulation, vertical mixing, dissolved oxygen and chlorophyll a. To obtain good agreement between observed and predicted dissolved oxygen and chlorophyll a distributions, it was necessary to simulate a unique characteristic, the diurnal vertical migration of Mesodinium.
Quantification of Wind Induced Resuspension in a Shallow Lake
Authors: Aalderink R. H. , Lijklema L. , Breukelman J. , van Raaphorst W. , Brinkman A. G.
Published: May 2018

The mass balance of suspended solids in a shallow lake was modelled as the net result of resuspension and settling. Four different formulations for the flux of resuspension were used. Two equations were based on the conception of wave induced resuspension, the other two used the flow field induced shear stress as the driving force for resuspension. Parameter estimations based on experimental time series of wind velocity and SS concentration produced lower least square values with the models based on flow induced resuspension. The model parameter representing settling was in reasonable accordance with the settling velocity obtained from sediment traps. The spread in results can be explained by a lack of homogeneity and horizontal transport.
The Behaviour of Suspended Sediments and Muds in an Estuary
Authors: Umita T. , Kusuda T. , Awaya Y. , Onuma M. , Futawatari T.
Published: May 2018

The fundamental behaviour of suspended sediments and muds was investigated using an annular flume with the condition of cyclically changed shear stress. The results from two series of experiments showed that particle sizes which participate in the variation of suspended sediments were restricted to smaller sizes of the material. It was also found that the cyclically steady state was finally attained with respect to the suspended sediments as the tidal cycle repeated. In that state the suspended sediments were subject to three phenomena: erosion; deposition with dispersed state; and deposition with flocculation. A simple model on the suspended sediments in an estuary was developed and its behaviour in a model estuary was simulated by using the fluxes of erosion and deposition in the experiment. That model well described the variation of the suspended sediments and muds.
Stabilization of Organic Carbon and Nitrogen in Consolidating Benthal Deposits
Authors: Bryant C. W. , Rich L. G.
Published: May 2018

The objective of this research was to develop and validate a predictive model of the benthal stabilization of organic carbon and nitrogen in deposits of waste activated sludge solids formed at the bottom of an aerated water column, under conditions of continual deposition. A benthal model was developed from a one-dimensional, generalized transport equation and a set of first-order biological reactions. For model verification, depth profiles of the major interstitial carbon and nitrogen components were measured from a set of deposits formed in the laboratory at 20°C and a controlled loading rate.

The observed sequence of volatile acid utilization in each benthal deposit was that which would be predicted by the Gibbs free energies of the individual degradation reactions and would be controlled by the reduction in interstitial hydrogen partial pressure with time. Biodegradable solids were solubilized rapidly during the first three weeks of benthal retention, but subsequent solubilization occurred much more slowly.

The benthal simulation effectively predicted the dynamics of consolidating, organic deposits. Simulation of organic loading rates up to 250 g BVSS/(m2 day) indicated that the stabilization capacity of benthal deposits was far above the range of organic loading rates currently used in lagoon design.
Tidal Variation of Salt Flux and Dispersion in a Polluted Estuary
Authors: Park J. K. , James A.
Published: May 2018

Velocity and salinity data collected during the summer of 1983 in the Tyne estuary are used to investigate the dominant mechanisms for the flux of salt and dispersion. The instantaneous salt flux arises mainly from the combination of velocity fluctuation with the tidal mean salinity, and the instantaneous dispersion results almost entirely from the combination of vertical oscillatory velocity and steady salinity. Of the net downstream salt flux, 92.4% is accounted for by the river discharge. The non-tidal drift appears to be of most importance in the net upstream salt flux. The estuary has a strong vertical salinity gradient and due to the strong secondary flow, has a uniform transverse gradient; thus, the dominant factor in the longitudinal dispersion arises from the vertical shear in the oscillatory tidal current. The dispersion coefficient is highly time-dependent within the tidal cycle as well as a function of distance. The importance of time-varying longitudinal dispersion coefficients are demonstrated in a water quality model by using the sensitivity analysis.
Infrared Thermal Regeneration of Spent Activated Carbon from Water Reclamation
Authors: van Vliet B. M. , Venter L.
Published: May 2018

An infrared conveyor-belt furnace was evaluated and utilized to conduct a parametric study on the effects of temperature and residence time on spent granular carbon intraparticle structure and concomitant regeneration efficiencies, incorporating an appraisal of the efficacy of low-temperature long-residence-time regeneration conditions. In addition, a virgin carbon of the same type and particle size fraction as was used in the above regeneration study, was subjected to equivalent temperature and residence time conditions to serve as a control experiment designed to shed light on the effects of regeneration conditions on the activated carbon per se. The infrared furnace proved to be an effective system for the regeneration of spent carbon; and an optimum operating region of 800 °C/10 min to 850 °C/5 min was identified. Temperatures in excess of 850 °C, regardless of residence time, must be avoided since excessive structural and pore volume distribution degradation is effected.
Modelling of the Coagulation–Adsorption Process in Treatment Systems
Authors: Dziubek Andrzej M. , Kowal Apolinary L.
Published: May 2018

Removal of organics in water or wastewater treatment systems is often described mathematically in the form of Langmuir and Freundlich adsorption isotherms. Using these equations, it is convenient to model, e.g., the removal of organic matter in the adsorption process on an activated carbon bed. In chemical treatment processes, organic substances are frequently removed from the water or wastewater under treatment via an adsorption on the precipitation products.

In this paper presented is a generalized model of the equation of a multilayer adsorption isotherm, which describes TOC removal from a solution during chemical treatment in an alkaline medium. The model also includes the nonremovable concentration of organics.
Modeling Water Quality and the Effects of Agricultural Best Management Practices in the Iowa River Basin
Authors: Bicknell B. R. , Donigian Anthony S. , Barnwell T. A.
Published: May 2018

This paper describes a demonstration application of comprehensive hydrology and water quality modeling on a large river basin to evaluate the effects of agricultural nonpoint pollution and proposed best management practices (BMP). The model application combines detailed simulation of agricultural runoff and soil processes, including calculation of surface and subsurface pollutant transport to receiving water, with subsequent simulation of instream transport and transformation. The result is a comprehensive simulation of river basin water quality.

The investigation of the Iowa River Basin described in this paper was part of a large study which included application and evaluation of the Hydrological Simulation Program - FORTRAN (HSPF) to both the data-intensive Four Mile Creek watershed and the Iowa River above Coralville Reservoir. In this study, the methodology developed on Four Mile Creek was extrapolated to the Iowa River Basin to demonstrate its applicability and functionality on a large river basin. Many model parameter values from Four Mile Creek were applied directly to the study area without adjustment while other parameters were modified based on available information and calibration. This study allowed the exploration of problems associated with modeling hydrology, sediment, and chemical fate and transport in a large river basin with varying meteorologic conditions, soils, and agricultural practices.
Surface Water Quality in Relation to Soil Type, Land use and Discharge in a Rural Catchment Area
Authors: Witmer M C. H.
Published: May 2018

Surface water quality and the factors that influence it were investigated in a rural area that lies between an ice-pushed ridge and river backlands. The influences of soil type, land use and household wastewater on the concentrations of nutrients were studied during base-flow as well as peak-flow periods. Samples were taken in ditches and canals, more frequently as discharge increased. Average values of the base-flow quality in ditches were calculated per soil type and land use and for all measure points in the canals. The fluctuations of water quality were plotted and analyzed in concentration-time and concentration-discharge diagrams. The relative importance for the quality of total discharge in the main canal of the loads coming from several parts of the drainage basin, was investigated with a stepwise multiple variable regression analysis. During base-flow situations sources of nutrients are the intensively cultivated sandy soils. In addition the concentration of orthophosphate is increased by household wastewater. During peak-flows, potassium and nitrate run off from all soil types with all types of land use, resulting in high concentrations in the surface water, in spite of dilution by rainwater. It is concluded that for proper management, intensity of manuring and fertilizing should decrease, especially on sandy soils. Wastewater should be drained outside the basin, to lower the concentration of orthophosphate.
Marine Quality Standards: Their Derivation and Application in the United Kingdom
Authors: Mance G. , O'Donnell A. R.
Published: May 2018

This paper discusses the derivation of environmental quality standards for coastal waters and the difficulties of using such standards for controlling industrial discharges. Attention is focused on the common List II substances, copper, chromium, lead, nickel, zinc and arsenic - and their effects on marine life. The adequacy of existing toxicity data is discussed and it is concluded that long exposure tests are required to provide information on sublethal effects. Such data are currently limited. It is also important that consideration be given to the effects that reducing salinities and increasing temperatures have in increasing the toxicity of these substances. The complexity of interpreting the results of laboratory toxicity data to coastal waters is discussed with reference to a study of the impact of an industrial discharge.
The EEC Shellfish Directive in Wales
Authors: Young S. N. , Wathern P.
Published: May 2018

This paper contains details of the procedures adopted by the UK Government in implementing the EEC shellfish directive and a review of the water quality monitoring programmes used by the Welsh Water Authority with respect to these provisions. Six shellfish beds have been surveyed in detail by the Authority, but only one has been designated. This is the only shellfishery which meets the standards. Raising the remainder to the required standards would involve considerable capital expenditure, mainly for sewage treatment. The UK Government has precluded such expenditure. It has claimed that any public health measures inherent in the directive are covered adequately by current UK practice. This stance is questioned in the light of a recent viral study. This paper highlights the potential problems when there is conflict between international and national water quality priorities.
Factors Affecting Biological Removal of Phosphorus
Authors: Fukase T. , Shibata M. , Miyaji Y.
Published: May 2018

A pilot plant study on biological removal of phosphorus was conducted over fifteen months to obtain optimum operational conditions and evaluate process performance. The pilot plant was composed of an anaerobic zone followed by an aerobic zone, and had a capacity of treating 100 m3 municipal wastewater per day. In the anaerobic zone, BOD loading rates and BOD to MLSS ratios were found to be important factors. In the aerobic zone, on the other hand, the hydraulic retention time had a significant influence on the phosphorus removal efficiency. For successful removal of phosphorus, a shorter hydraulic retention time in the aerobic zone along with appropriate parameters in the anaerobic zone (BOD loading rate ≦ 2 kg-BOD/kg-MLSS day, BOD to MLSS ratio ≦ 0.1 kg-BOD/kg-MLSS) are essential.
Full Scale Optimization of Biological Phosphorus Removal at Kelowna, Canada
Authors: Oldham W. K.
Published: May 2018

A newly constructed biological nutrient removal treatment plant operating in the Phoredox mode was used to test the effects on plant efficiency of varying two important operating conditions - the point of introduction of return sludge flow, and the addition of primary sludge thickener supernatant to the bioreactor. Overall treatment results for Kelowna's weak sewage showed that the effluent was consistently below 10 mg/L BOD and 4 mg/L suspended solids, while total P was below 2 mg/L 94 percent of the time, and total N was below 6 mg/L 90 percent of the time. There was no significant difference in effluent nutrient quality between tests with all return sludge entering the anaerobic zone or with half entering the anaerobic zone and half entering the first anoxic zone. Primary sludge thickener supernatant added to the anaerobic zone typically resulted in an effluent P concentration of less than 0.1 mg ortho-P/L, while the absence of supernatant produced an effluent containing greater than 2 mg ortho-P/L.
Two Options for Treatment of Acidic Organic Industrial Wastes
Authors: Millot N. , Dalga N. , Foussard N.
Published: May 2018

The treatment of acidic, organic, industrial wastes poses many problems. These wastes are characterized by a high organic concentration and pH values approaching zero. The classic treatment processes (incineration, physicochemical treatment, solidification) are plagued by problems with corrosion, by-products formation and ultimate disposal.

This paper proposes two new processes for treating these wastes. The first technique is a pressurized oxidation process at high temperature. Results show total organic carbon (TOC) removal above 96%.

The second proposed technique is an improved solidification which incorporates an adsorbent into the solid to immobilize the organic content. A very thick sludge (solids about 60%) is obtained which dries very quickly. Tests on the solids indicate that any leachate formed will be much lower in strength than leachate from the classic solidification process.

Landfill disposal of the solidified waste is possible under proper conditions.