bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristics of Storms over Urban Areas in East Africa
Authors: Sumner G N
Published: May 2018

Storm morphologies and associated intensity profiles are examined using data taken from dense pluviograph networks in East Africa. Different morphologies of storms are illustrated with use of examples for Dar es Salaam, Tanzania and Kampala, Uganda. Generally storms of elliptical form dominate for inland East Africa, but along coastal and lake margins, storms of a more linear form are envisaged as important contributions to rainfall. Storm size, development and form are good indicators of the magnitude of maximum storm depths and intensities. Although storms belonging to several different morphologies may occur the distribution of rainfall with time through a storm appears consistent for the majority: the heaviest falls occur very early in the storm.
Statistical Methods of Storm Analysis
Authors: Vukmirović V D , Despotović J Ž
Published: May 2018

The purpose of this high intensity rainfall analysis is quantization of a rainfall phenomenon. Hereafter the statistical methods are presented but only the basis of these, also the application to some real rainfall data and finally the differences among those methods are discussed. The most important components of a calculation by different methods are presented by an example. The complex information concerning small duration high intensity rainfall is useful for both hydrologist and design engineer and also necessary for urban run-off calculations and drainage system analysis.
Rainfall as the Basis for Urban Runoff – Experience and Practice in Yugoslavia
Authors: Bonacci O
Published: May 2018

This paper presents experiences in Yugoslavia in dealing with intensive rain which serve as a basis for design and analysis of urban runoff. In Yugoslavia there are about 25G pluviographs and 3GGG rain gauge stations with daily data recordings over an area covering 255804 km2. Such rain gauge network stimulates some specific conditions in dealing with rain as input vector into the system. This study presents a short review of problems in the treatment of intensive rains with the objective of defining a family of intensity-duration-frequency curves. High variability and significant changes in characteristics of intensive rain in space and time are discussed. This fact, particularly the direction of storm movement, significantly affects the formation of runoff processes, i.e. outflow hydrograph. We described a method for the reduction of rainfall from a point to a surface suitable for regions where there are only few pluviographs for recording intensive rains. We suggest the genetic method for computing the runoff process, based on the definition of isochrones applied to dynamic programming.
Depth-Duration Models of Short Time Increment Rainfall
Authors: Ramachandra Rao A , Chenchayya B T
Published: May 2018

The depth-duration characteristics of short time increment (10 min. and hourly) rainfall sequences are investigated in the present paper. The basic objectives of the study are to investigate the models proposed for storm depths and durations and to investigate the effect of different time scales on modelling the process. Both regression and bivariate probability distribution models are used in the study. Hourly and 10-minute rainfall measured at Lafayette, Indiana are used in the study.

The following principal results are obtained from the study. Regression models for storm depth-duration relationship are adequate when they are used with appropriately classified storms. Significant differences and some surprising similarities are found in the characteristics of short time increment rainfall processes in different climatic regions. Finally, the characteristics of the 10 minute and hourly data are quite similar to each other.
On Stochastic Characterization of Temporal Storm Patterns
Authors: Nguyen Van-Thanh-Van
Published: May 2018

The present study, a continuation of a previous work by the author, suggests a new theoretical approach to the characterization of the temporal pattern of storms. A storm is defined as a continuous run of non-zero one-hour rainfall depths. A general stochastic model is developed to determine the probability distributions of cumulative storm rainfall amounts at successive time intervals after the storm began. The previous model for characterizing storm temporal patterns was based on the assumption that hourly rainfall depths were independent and identically exponentially distributed random variables, while sequences of wet hours were modeled by a first-order stationary Markov chain. Hence, the model did only introduce dependence of wet hour occurences into the rainfall process through the first-order Markov chain. The present paper proposes a more general model that can take into account both the persistence in hourly rainfall occurrences and the dependence between successive hourly rainfall depths. Results of an illustrative example show that by accounting for the correlation structure of consecutive rainfall depths the present model gives a better fit to the observations than the previous one.
A Staged Approach to Application of Rainfall Data to Urban Runoff Calculations
Authors: Harremoës P , Jensen M , Johansen N B
Published: May 2018

The paper presents a coherent approach to application of rain data from long rain records. It is a staged approach based on the principle that a spectrum of methods should be made available to the practitioner, from the simplest calculation by hand to the most advanced application of historical rain events as input to the most complicated computer programmes. The simplest method is the traditional use of i-d-f-curves and the rational method. From that basis there are stages of increasing sophistication up to Utopian use of all the best means. The choice of method depends on the level of ambition and the accuracy of the basic input data for the catchment in question.
Rainfall Data for the Design of Detention Basins
Authors: Arnell Viktor
Published: May 2018

This paper decribes the selection of rainfall data for design of detention basins. The use of design storms (the uniform intensity design storm, the Chicago design storm and the Sifalda design storm) were compared with the use of historical storms where the historical storms were assumed to give the most correct result. Historical storms were selected from an 18-year rainfall record and local coefficients were estimated from the same record. Three test catchments were used and detention basins were located at the outlet of each basin. For the runoff simulations were used the CTH-Urban Runoff Model which also includes a detention basin submodel. The results show the importance of the design storms having total volumes that correspond to the volumes of the historical storms. The use of the uniform intensity design storm and the Chicago design storm resulted in underestimated detention basin volumes. The Sifalda design storm caused overestimated basin volumes which can be reduced after an improvement of the storm.
Rainfall Energy from Drop Size Data
Authors: Quimpo Rafael G , Brohi Ali-Bux
Published: May 2018

The washoff of pollutants from urban surfaces by storm events depends on the kinetic energy of storms. In order to determine the erosive power of rainfall, data on raindrop size distributions were analyzed and the kinetic energy expressed as a function of rainfall intensity. Results indicate that the regression equation that is currently used to determine storm erosive power from rainfall intensity needs to be revised.
Real-Time Estimation and Forecasting of Spatially Distributed Areal Rainfall
Authors: Schilling Wolfgang
Published: May 2018

After a short demonstration about the need for operational rainfall forecasts, a literature survey, constraints for model development and definition of criteria of model performance a simple multi-variate autoregressive model is presented that forecasts point rainfall spatially distributed, for short lead times, quantitatively and automatically. For model operation only remotely transmitted standard raingage data is necessary.

The model is expanded to forecast and estimate also areal rainfall from point measurements using the Kaiman filter technique and the theory of regionalized variables.

It is demonstrated that the Kaiman filter model is superior for areal rainfall estimation (compared to the Thiessen procedure) as well as for areal rainfall forecasting compared to trivial forecasts and the point forecasting model mentioned above.
The Use of a Color TV Technique for Measuring Filament Length and Investigating Sludge Bulking Causes
Authors: Matsui Saburo , Yamamoto Ryoko
Published: May 2018

Since activated sludge bulking is often observed in connection with growth of filamentous bacteria and fungi, the measurement of the lengths of these microorganisms has been recognized to be increasingly necessary. A microscopic measurement is, however, very time consuming and requires well trained skill. A simple and short but accurate method was developed using a color TV connected to a microscope through a video camera. The measurement of lengths of the microbes takes place on the TV screen tracing the filaments with a map meter which is a length measuring device. This method was statistically evaluated for accuracy and gave satisfactory results. Measurement of many samples from various activated sludges showed a good correlation between the total length of filamentous microbes and settleability of sludges. When the total length increases over 103 cm/ml of mixed liquor or 103 cm/mg of MLSS, Zone Settling Velocity, SVI, a new index of SVI at Phase I and other indexes of sludge settling become unfavourable figures. Measurement of the lengths as a daily routine work can give a trend of increase and decrease of filamentous microbes and thus probably forecast an occurrence of filamentous bulking.
Nitrification and Denitrification in Single-Stage Activated Sludge Plants – Operational Results of the Lüdinghausen Waste Water Treatment Plant, F.R.G.
Authors: Schlegel S
Published: May 2018

About 15,000 Population Equivalents are connected to the Lüdinghausen Waste Water Treatment Plant of the Lippeverband. The activated sludge stages, designed for 30,000 PE and a BOD5 sludge load of 0.3 kg/(kg · d), are, thus, at present operated with a sludge load of 0.15 kg/(kg · d), i.e. in the nitrification range. In order to reduce energy costs for aeration and prevent possible sludge losses resulting from the denitrification processes, the aeration tanks are equipped with denitrification zones.

Because of the loading conditions, the only possible denitrification method was that of primary denitrification. However, contrary to usual practice, a multi-stage cascade, comprising two denitrification and two nitrification tanks, was installed.

Apart from a very high degree of nitrification, nitrate is eliminated to a farreaching degree. Better reduction of BOD5 and COD is also attained. Moreover, the settlability of the activated sludge is, compared to earlier conditions, substantially more favourable.
Biological Phosphorus and Nitrogen Removal via the A/O Process1: Recent Experience in the United States and United Kingdom
Authors: Hong S , Krichten D , Best A , Rachwal A
Published: May 2018

This paper summarizes the state of the art of the proprietary A/01 system for biological nutrient removal. The A/0 system is a modified form of the activated sludge process employing an anaerobic zone to promote biological phosphorus removal. Process options discussed include BOD oxidation, biological phosphorus removal, nitrification and denltrification. The biochemical basis for phosphorus removal is reviewed. Results of several pilot studies and a 11400 m3/day demonstration plant operated for 3 years are given.

1A/O is a registered trademark of Air Products and Chemicals, Inc., Allentown, Pennsylvania, USA.
The Use of Biofiltration for Further Wastewater Treatment
Authors: Rüffer H , Rosenwinkel K.-H
Published: May 2018

The City of Mannheim (FRG) expanded its one stage biological treatment plant by addition of a second stage based on dry bed filtration and designed for an average wastewater flow of QTW = 8.800 m3/h and an average BOD5 of 70 mg/l. Five firms in the foreground of process selection conducted from 1980 to 1982 experiments on purification systems for the effluent from the first biological stage. Systems tested were biofiltration in dry and submerged beds and activated two sludge systems.

Filter materials used were inert material, activated carbon and Biolite. In one case a pretreatment by coagulation was employed. The influent of submerged filters without coagulation was supplied with technical oxygen whereas submerged filters with coagulation were supplied with atmospheric oxygen.

The two sludge process employed a plastic medium (Flocor E) in an aeration tank of up to 40% total bed volume; aeration was achieved with compressed air. The results of the submerged filtration tests are compared to those of the two sludge system with respect to retention of suspended solids, elimination of BOD5 and COD and soluble and total nitrogenous compounds. A procedural evaluation and cost comparison are made. In addition the problems that arise by solution of oxygen up to high concentrations are indicated and solution possibilities discussed.
Anaerobic Biological Decomposition of Malodorous Compounds in Kraft Pulping Wastewater
Authors: Endo G , Tohya Y
Published: May 2018

The capability and performance of anaerobic biological decomposition of malodorous compounds in kraft pulping wastewater were studied. The experimental apparatus used in this investigation was a bench-scale semi-batch anaerobic contact process of which a digester vessel was operated in regular sequence as a stirred digester and a stationary sedimentation tank. The results obtained from this experiment revealed that digesting anaerobic sludge could convert dimethyl disulfide (DMDS) to methyl mercaptan (MM) and that MM was partially decomposed into H2S. To maintain this anaerobic biodegradation of sulfur-containing malodorous compounds, the concentration of H2S in digester mixed liquor was required to be kept below about 5 mg/L. The conditions of temperature of 50 °C and pH of 6.5 were most suitable for the methane fermentation of the kraft pulping waste steam drainage and for the removal of the malodorous compounds. Scrubbing of the digester head space gas with the solution of sodium hydroxide removed not only H2S but also MM, so that a high removal rate of DMDS and MM was achieved. Unfortunately, dimethyl sulfide (DMS) could not be decomposed biologically, but it could be removed easily with a simple air stripping process. From these results, an effective process combined with anaerobic digestion for the economical prevention of odor nuisance was proposed.
Anaerobic Treatment of Wastewater from the Production of Chemi-Thermomechanical Pulp
Authors: Welander T , Andersson P.-E
Published: May 2018

The anaerobic treatment of waste water from the production of peroxide-bleached chemi-thermomechanical pulp was studied. Hydrogen peroxide had to be removed from the waste water before treatment in a methane producing reactor was possible. Peroxide in concentrations up to 200 mg/1 could be removed from the waste water by means of degradation in an acidogenic reactor, the first stage in an anaerobic two-stage process. A system consisting of a prestage and a subsequent acidogenic reactor could successfully remove peroxide in a concentration of 1200 mg/l from the waste water. The prestage was continuously fed with sludge from the acidogenic reactor. The redox potential in the acidogenic stage of a two-stage process proved to be a valuable control parameter when treating waste water containing peroxide. Adaptation of the methanogenic microflora to inhibitory compounds in the waste water was possible. Treatment of the waste water in a pilot plant at low loading rates gave a COD reduction of 50-60% and a methane yield of 0.3 Nm3/kg COD reduced.
Anaerobic Treatment of Sulphite Evaporator Condensate in a Pilot Plant of Novel Design
Authors: Gunnarsson L , Rosén B
Published: May 2018

Sulphite evaporator condensate has been treated in an anaerobic pilot plant, consisting of two separate units. One unit was an ordinary mixed reactor. The second reactor was identical with the first one, but additionally it contained a plastic medium as a fixed bed reactor. The agitator in the reactor provided circulation through the medium. Both reactors had internal sedimentation and no external settling device. The reactor with a fixed biofilm was more stable and had an over-all better performance than the reactor without a medium. Particularly the latter was severely disturbed by a momentaneous intrusion of high amounts suspended solids, which did not effect the former. Twelve weeks after the start of the tests, the fixed bed reactor was not yet in final equilibrium but despite that, at a loading of 0,5 m3/m3 and 6 kg COD/m3 × d, the COD-reduction was 66%, the BOD-reduction 84%, giving 68% methane in the biogas and 0,15 m3 CH4 was produced per kg COD added.
Direct Measurement of the Hydrogenase Activity of Anaerobic Microorganisms
Authors: Zábranská J , Dohányos M , Grau P
Published: May 2018

An electro-chemical method of direct measurement of the concentrations of dissolved hydrogen in the mixed culture of anaerobic microorganisms was used for the determination of the rates of hydrogen production and consumption. A certain modification of the Sweet's conception has been used in the design of the device. Experiments demonstrate that the hydrogenase activity expressed as a hydrogen consumption rate corresponds well with the activity of electron carrier and with the concentration changes of particular volatile fatty acids.
Algal Growth Potential Test: An Indicative Method to Estimate the Influence of Water Quality Changes on the Algal Biomass
Authors: Bolier G.
Published: May 2018

Algal Growth Potential Tests as known from literature cannot simply be applied in water quality management in the Netherlands; adaptation to the Dutch situation is necessary. Points of research were: pretreatment of the water to be tested, species of test algae, conditions of the cultivation, monitoring of the algae growth.
Chemical Transport Facilitated by Multiphase Flow Systems1
Authors: Enfield Carl G.
Published: May 2018

Relatively immobile chemicals have been observed moving significantly faster than anticipated from hydrophobic theory. A theory is developed considering transport in three mobile fluid phases which can be used to describe this facilitated transport. The convective dispersive transport equation is solved utilizing a transformation of variables which permits utilizing existing solutions covering a wide variety of boundary conditions. The impact of the facilitated transport is demonstrated for one case where the soils organic carbon is 10%. If 2% of the fluid phase is an organic fraction, the theory developed projects that hydrophobic theory may underestimate mobility by more than 100 times. At concentrations of dissolved organic carbon normally observed in nature (5 - 10 mg/l), a measurable increased mobility is anticipated for the very immobile compounds like dioxins.
Trace Metal Speciation in a Soil Profile Irrigated with Waste Waters
Authors: Mattigod S. V. , Pratt P. F. , Schalscha E. B.
Published: May 2018

A chemical equilibrium computer model: GEOCHEM, was used to predict the trace metal behavior in a soil profile if subjected to a long-term irrigation with waste waters. Various categories of interactions such as acid-base equilibria, soluble complex formation of metals with organic and inorganic ligands, dissolution-precipitation reactions and ion-exchange reactions were included in simulation. The metal-soluble organic interactions were accounted for by a mixture model. The computations included a 10 metal - 15 ligand system with 262 soluble complex species and 21 possible solid phases. The results predicted that a major fraction of alkali elements in solution tend to be in free ionic forms, whereas, major fractions of the alkaline earths were predicted to be present in adsorbed and/or precipitated forms. In marked contrast, significant soluble fractions of transition series metals were predicted to be in adsorbed and/or complexed forms. The degree of attenuation of these transition series elements moving through the soil profile seems to be governed mainly by the degree of adsorption on soil surfaces and the tendency of these elements to form soluble organic complexes. The predicted mobilities of these elements in this soil profile was Cu > Ni > Zn > Cd. Application of this equilibrium model appears to provide a first approximation approach to simulate the trace element behavior in soil profiles.
Concentration of Seeded and Naturally Occurring Enteroviruses from Waters of Varying Quality by Hollow Fiber Ultrafiltration
Authors: Bicknell E. A. , Dziewulski D. M. , Sturman L. S. , Belfort G.
Published: May 2018

A semi-automated hollow fiber ultrafiltration system was used to concentrate viruses from tap water, river water and treated and untreated wastewater. Samples were dehydrated by filtration through an asymmetric polysulfone hollow fiber module with a molecular weight cut-off of 10,000 D. Retained solute was recovered from the filter by backwashing with water, buffer and other solutions.

One hundred liters of tap water seeded with poliovirus type 2 Sabin were processed in 161 ± 22 minutes (average flux 1.2 ± 0.1 × 10−3 cm/sec). Retained virus was recovered from the filter by backwashing with 150 ml of 0.05 M glycine, pH 10.0, which was further reduced to about 10 ml by the organic flocculation technique. Average recovery of 60 plaque-forming units (PFU) of poliovirus from 100 1 of tapwater was 148 ± 10%.

Hudson River water (100 1 with an average turbidity of 3.2 NTU) was processed in 218 ± 34 minutes (average flux 0.8 ± 0.2 × 10−3 cm/sec). Recovery of 114 PFU of poliovirus seeded into 99 1 of river water was 35%. No natural virus was recovered from unseeded river water.

Naturally occurring viruses, tentatively identified as echovirus type 14, coxsackie virus type A9 and coxsackie virus types B2-B5, were isolated from concentrates qf treated and untreated wastewater (average fluxes 0.58 × 10−3 and 0.46 × 10−3 cm/sec, respectively).
Analysis of Tap Water for Viruses: Results of a Survey
Authors: Guttman-Bass Naomi , Fattal Badri
Published: May 2018

This paper is a preliminary report of the results of a survey which assayed drinking water for viruses on 30 rural settlements in Israel. Over the period of a year and a half, 111 samples were tested, and 3 were positive for viruses. The positive samples were from closely situated settlements, and were of relatively good bacteriological quality. The isolates were found in 300 1 samples which were concentrated on-site rather than in the laboratory (100 1 samples) and by plaque assay rather than cytopathic effect. Out of a total of 20,000 liters of water which were processed, 5 plaques were isolated.
Some Experimental Discussion of Accuracies in Quantitative Virus Assessment for Water Supply
Authors: Sumitomo Hisashi
Published: May 2018

Chlorination has been believed to be the best sterilization method in water supply engineering for many years. However, the recent carcinogenic problem of trihalomethanes (THM) formed from organic compounds by chlorination requires us to assess the public health risk of THM.

The author tried an assessment of a suitable chlorination technique considering both the effects of THM and viruses on human health, using Lake Biwa as a representative example of a water resource in Japan. Statistical handling of data was revealed to be important because of the statistical nature of the data. In other words, since both concentrations are very low in tap water, we need to quantify both the effects and concentrations with probabilities.

In the first part of this paper, a statistical procedure and numerical results of the assessment of virus and THM risks are shown. In the second part some results of accuracies in virus experiments are briefly shown. These experiments concerning statistical problems are particularly important for more precise assessment of the public risk of viruses in tap water.
Influence of Particulate Organics on the Removal of Dissolved Organics in Fixed-Film Biological Reactors
Authors: Särner E. , Marklund S.
Published: May 2018

Very little is known about the interaction between dissolved and particulate organics in the fixed-film biological process used for wastewater purification, although this process has been used for many decades. The mechanisms for the removal of dissolved and particulate organics differ and it has been found that a large fraction of the organics in most wastewaters exists in particulate form.

In the experiments described here, the influence of particulate organics on the removal of glucose was studied in laboratory-scale fixed-film reactors. The particles used were starch particles and particles obtained from digested sewage sludge. The result of the experiments showed that for high glucose concentrations and high temperatures the removal of glucose was reduced when particles were adsorbed on the biofilm surface. A dramatic reduction was observed when large amounts of particles were adsorbed. This effect has also been observed in a full-scale trickling filter plant and in pilot trickling filters. At low glucose concentrations and low temperatures, however, a slight increase in glucose removal was observed when organic particles were adsorbed on the biofilm surface.
The Effect of Load Fluctuations on the Effluent Concentration Produced by Fixed-Film Reactors
Authors: Rittmann Bruce E.
Published: May 2018

Although time-varying loads to biological treatment processes are common, typical kinetic models are based on steady-state loads and conditions. This paper uses nonsteady-state kinetics to demonstrate the impact of load variations on the effluent concentration and load from fixed-bed biofilm reactors. The different responses for reactors having average loads that are high, intermediate, and low are compared. In most cases, time-varying input loading, in comparison with steady input loading, causes an increase in average effluent concentration; however, certain combinations of load variation and reactor type allow better performance than do steady-state loads.
Phosphorus Removal from Wastewater by the Crystallization Method
Authors: Joko Isao
Published: May 2018

To develop a new process for phosphorus removal the calcium phosphate crystallization method has been investigated. The metastable zone of calcium phosphate precipitates which is defined by concentrations of phosphate and calcium ions and pH was determined by batch experiments. Phosphorus in wastewaters can be constantly reduced to a sufficiently low level at the metastable reaction zone under the presence of seed crystals. The crystallization method proved to be practicable as advanced technology for phosphorus removal from wastewater through column tests and 50m3/day pilot plant tests over 180 days with a sewage secondary effluent.
The Kinetic Analysis of Bod and Nitrogen Removal in an Oxidation Ditch
Authors: Terashima Y. , Ishikawa M.
Published: May 2018

The simultaneous removal of nitrogen as well as organic substances is one of important characteristics of the oxidation ditch process. To describe this phenomena, synthetic kinetic models including the rates of BOD oxidation, nitrification, denitrification, DO and alkalinity changes, and sludge growth were proposed in this study. Rate equations for these mechanisms were mainly based on Monod type kinetics taking into account several limiting effects among these mechanisms. To develop the design procedure, these kinetic models were combined with the tank-in-series model having circulating and back flows. They were analyzed numerically for typical design and operating conditions. From these computer simulations, successful results to explain these complicated phenomena and several design and operating bases were obtained.
Steady State Measurement of Oxygenation Capacity
Authors: de Korte Kees , Smits Peter
Published: May 2018

The usual method for OC measurement is the non-steady state method (reaeration) in tapwater or, sometimes, in activated sludge. Both methods are more or less difficult and expensive. The steady state method with activated sludge is presented. Fundamentals are discussed. For complete mixed aeration tanks, plug flow systems with diffused air aeration and carousels the method is described more in detail and the results of measurements are presented. The results of the steady state measurements of the diffused air system are compared with those of the reaeration method in tapwater. The accuracy of the measurements in the 3 systems is discussed. Measurements in other aeration systems are described briefly. It is concluded that the steady state OC measurement offers advantages in comparison with the non-steady state method and is useful for most purposes.
Removal of Iron Cyanide from Gold Mill Effluents by Ion Exchange
Authors: Vachon D. T.
Published: May 2018

Using a strongly basic anion exchanger (Rohm & Haas Amberlite IRA-958) laboratory ion exchange tests were conducted on the removal of iron cyanide from synthetic and actual gold mill effluents. Variables examined included the effects of pH, concentration and hydraulic loading of the feed on the resin exchange capacity and resin column utilization. The results showed ion exchange to be an effective method of removing iron cyanide to concentrations of less than 3 mg/L. Tests with synthetic gold mill effluents gave resin exchange capacities ranging from 13 to 34 mg CNFe/mL resin depending on the concentration of iron, copper and zinc cyanides in these solutions. When raw barren bleed was tested, an exchange capacity for the ferro/ferricyanides was determined to be ~6 to 8 mg CNFe/mL resin. For chlorinated barren bleed, a resin exchange capacity of 14 mg CNFe/mL resin was observed. A capacity of 19 mg CNFe/mL resin was achieved for tailings pond decant.

Regeneration with 15% NaCl provided mixed results with recoveries ranging from 40 to 100% of the iron cyanide exchanged by the resin. Upon multiple exchange-regeneration cycles, the resin lost 25% of the exchange capacity for total cyanide during the first cycle. Subsequently, the loss in exchange capacity was approximately 1% per cycle. Pilot scale tests were considered essential prior to full scale system design.
Production of Liquid Alum from Aluminum-Anodizing Sludges
Authors: Saunders F. M. , Harmon C. B.
Published: May 2018

The potential for reclamation of dewatered aluminum-anodizing sludges as liquid alum was investigated. Batch extractions with sulfuric acid at elevated temperatures indicated that liquid alum production was feasible. Sludge solids content was shown to be a critical variable if commercial-strength products (8.0 to 8.3 percent as Al2O3) are to be produced.
Water Quality Control of the Andelse Maas Basin, The Netherlands, by Iron Dosing
Authors: Hoekstra A. C. , Maiwald K. D.
Published: May 2018

The Dune Water Works of The Hague pumps yearly about 45 million cubic meters of water from the Andelse Maas Basin to the dunes for infiltration purposes. The water in the Andelse Haas Basin is strongly influenced by the Meuse river. Phosphate concentrations are so high that algal growth causes difficulties in filters and dunes. For phosphate reduction purposes, iron is dosed into the basin. Several limnological variables are monitored based on weekly measurements. A mathematical model has been developed for the description of the eutrophication in the basin. The model is time and space dependent and based on the one-dimensional dispersion-advection equation. Two separate submodels are used, one for the simulation of flow conditions and one for the algae and nutrient kinetics. The ortho-phosphate reduction is modelled as a first order process. The eutrophication model has been calibrated, verified and used for a prediction of chlorophyll-a and ortho-phosphate concentrations for the case of the shut down of the iron dosing installation. The dosing of iron appears to be a very effective way for phosphate removal. Termination of the dosing would give unacceptable high phosphate and chlorophyll-a concentrations. Present investigations are focussed upon the minimization of the amount of iron dosing.
The Application of Information about Conductivity in the Computing of Ion Concentrations, Illustrated by Certain Surface Waters Situated in Lower Saxony
Authors: Walther W. , Gorsler M. , Poltz J. , Bock D.
Published: May 2018

The electrical conductivity and pH value are, amongst other parameters, continuously recorded in monitoring stations at important surface waters in Lower Saxony. The data are directly transmitted to the surveillance centre in Hildesheim. This paper deals with the estimates of concentrations of the most important ions in water by using mathematical models. The basis for the calculations are the conductivity and, in case of a eutrophic lake, the pH value as well. The methods are demonstrated by using data from the river Weser and from the shallow lake Dümmer. The Weser is one of the main rivers in Lower Saxony. It is heavily polluted by potash mine wastes.
Ozone Enhanced Biological Activated Carbon Filtration and its Effect on Organic Matter Removal, and in Particular on AOC Reduction
Authors: Janssens J. G. , Meheus J. , Dirickx J.
Published: May 2018

Ozonation prior to GAC filtration is evaluated in relation to organic matter removal, and in particular to AOC (assimilable organic carbon) reduction. In terms of TOC removal, experimental results on pilot plant scale showed an increase of filter service time with about 60 % to 65 %. A dosage higher than 2 mg ozone/1 had no additional effect. The extent to which this increase of service time was predominantly due to enhanced biological activity or to long term cumulative slow adsorption is not yet clear.

Ozonation caused a very significant increase of AOC. This increase was a function of the applied ozone dosage. First experimental results suggested a relation between ozonation and an early “breakthrough” of AOC with GAC filters fed with ozonated water.
The Contribution of Agricultural Loading to Eutrophication in Finnish Lakes
Authors: Kauppi L.
Published: May 2018

Agriculture accounts for 9 per cent of the total surface area of Finland and generates the greatest single nutrient input to Finnish watercourses. Since agricultural activity is scattered throughout the whole country its effects in lakes are less pronounced than those of domestic and industrial effluents. On the other hand, point source phosphorus loading of lakes and rivers decreased significantly during the nineteen-seventies.

Phosphorus is the nutrient which primarily limits production in most Finnish lakes. The availability of phosphorus in agricultural runoff waters is therefore a crucial question in the evaluation of the eutrophicating effects of agriculture. Our results indicated that in runoff waters available phosphorus can be 60-70 per cent of the total phosphorus. However, the concentrations of available P were so low that they could be achieved in Finnish lakes of low ionic concentration through simple chemical desorption without the assistance of the algal uptake. The utilization of the spring maximum of runoff phosphorus in lakes would thus not depend on the concurrence of the maxima of loading and algal growth.
Operation and Efficiency of Automatically Operating Weir Structures – A Contribution to Cleaner Waters
Authors: Macke E.
Published: May 2018

The automatically operating weir structures presented are simple, largely maintenance-free structures which, when used as control elements in storm overflows, offer considerable advantages over the fixed weir sills. Irrespective of the intensity of rainfalls, these weirs do not discharge any surplus water into the receiving water, unless a maximum possible water level has been reached, which is then maintained at a virtually constant level until the floods subside. The maximum possible water level, the so-called impounding head, will be determined in such a way that, on the one hand, the sewer capacity will be fully utilized, and, on the other, any undesirable backwater in the sewer system can be precluded. The weirs are not only suited for installation in new structures, but may also be integrated in existing ones. Time and cost consuming constructional measures can be dispensed with, as the weirs can, owing to their configuration - they are composed of individual segments - be passed through the existing manholes. They allow considerable additional sewer capacities to be activated, in particular in low-head sewer systems, so that the installation of high-cost retaining basins, which normally require a high degree of maintenance, can either be limited or dispensed with altogether. As the receiving water will be affected only when a given impounding head has been reached, the amount of combined sewage discharged can be reduced to a minimum.
Sedimentation, Mineralization and Resuspension of Sludge in a Sewerage System: A Case Study
Authors: Hogendoorn-Roozemond A. S.
Published: May 2018

Quantitative information was obtained on the processes of sedimentation, mineralization and resuspension of organic matter in a combined sewerage system by means of statistical analysis of dry and wet weather data on sewage flows.

The effects of temperature and length of intermittent dry weather periods on daily pollutant loads were also evaluated.

For the sewerage system investigated it was found that in summer 5-26% of the BOD produced is mineralized in the system before reaching the sewage treatment plant. Due to sedimentation under dry weather conditions up to 12% of the daily organic load produced may be present in the sewers as resuspendable deposits; in winter this percentage may even amount to 20-30% because of slow mineralization.
Biological Phosphorus Removal in Combination with Simultaneous Precipitation
Authors: Spatzierer G. , Ludwig C. , Matsché N.
Published: May 2018

Two treatment plants - in the drainage area of Lake Neusiedl in Burgenland (Wulkatal, Eisbachtal)-with nitrification-denitrification and simultaneous precipitation of P were operated with an anoxic -anaerobic aeration tank to obtain biological P-removal. The results indicated that a complete denitrification is essential in the first tank to obtain release and biological uptake of phosphorus. Low loading in the Wulkatal-Plant resulted in incomplete denitrification and a biological P-removal of only 60 %. The dosage of a reduced amount of precipitant indicated a combined action of chemical and biological P-removal. In the Eisbachtal Treatment Plant with the same mode of operation - two aeration tanks of which the first was kept anoxic-anaerobic - a biological P-removal of more than 90 % was obtained under optimal process conditions. At low temperatures the removal efficiency was reduced. This could, however, be compensated by a reduced amount of precipitant. An average addition of about 1 g Fe/gP which is far below the theoretical amount for precipitation resulted in effluent concentrations below 1 mg P/1 over a period of two and half years.

At the high loaded Main Treatment Plant of Vienna (F/M ratio about 1 ky/kg.d) which has plug flow conditions in the aeration tanks and ferrous sulfate addition for the control of bulking, a significant biological P-removal has been observed. According to measurements at the 400.000 m3/d plant about 50 % of the P is removed by additional biological uptake.
Microbial Aspects of the Inuvik Sewage Lagoon
Authors: Henry J. G. , Prasad D.
Published: May 2018

A facultative sewage lagoon in Inuvik, N.W.T. was studied in August (ice free) and November (ice covered) 1984. Emphasis was placed on the microbiological aspects and their relation to lagoon performance. Analyses performed included, pH, total alkalinity, total solids, suspended solids, volatile solids, COD and BOD5 determinations. The microbiological tests included total plate counts (20°C) and psychrotrophic counts (1°C).

Results indicated that the Inuvik sewage lagoon system achieved removal efficiencies, ranging from 90% BOD5 removal in summer to about 80% in winter. The total bacterial count was found to decrease in the liquid of the primary cells in the winter, but the bacterial count in the secondary cell was similar under both winter and summer conditions. No significant difference existed in bacterial counts in the sludge samples between primary and secondary cells. The total bacterial number decreased by one order of magnitude in the winter in sludges from all cells. A shift from mesophilic to psychrotrophic bacteria occurred in the winter. The percentage of psychrotrophs increased from less than 1% to over 80% with the change in season. The role of psychrotrophs in lagoon performance is discussed.
Lagoon Treatment of Municipal Sewage Effluent in a Subarctic Region of Canada (Yellowknife, N.W.T.)
Authors: Soniassy Ranjit N. , Lemon Rodney
Published: May 2018

The performance of a municipal sewage lagoon in a subarctic climate (Yellowknife, N.W.T.) was evaluated over a one year period to determine its seasonal treatment capabilities. Raw sewage (influent) and treated effluent were analysed for several physicochemical and microbiological parameters. Effective removals of BOD5, total coliform, fecal coliform, fecal streptococci and heavy metals (Cu, Ni, Zn, Cd, Pb and Hg) were obtained from mid-June to mid-September. No evidence of treatment was observed when the lagoon was under ice cover (October to May). The concentrations of several heavy metals (Cu, Zn and Pb) were found to decrease gradually, reaching a low in summer, before rising again in the fall and winter. A system of managing cold climate lagoons, based on ambient temperature, is presented.
Palm Oil Processing – New Development in Effluent Treatment
Authors: Ma A. N. , Ong A S. H.
Published: May 2018

Since 1980, the concept of palm oil mill effluent treatment has changed, and there have been several research and development projects to investigate the utilization of the so called waste materials from the palm oil mills. A pollution prevention approach has been increasingly adoted by the industry. Anaerobic liquor is being beneficially recycled to crops and improved crop yield and soil properties have been recorded, and biogas is being harnessed for heat and electricity generation. This paper highlights some of the recent developments.
The Treatment of Waste Waters from Malting, Brewing and Distilling
Authors: Smith L. J.
Published: May 2018

The origin and nature of the waste waters is briefly described. Possible methods of treatment are reviewed with passing reference to some typical examples. The effect of climate is considered. The second half of the paper is devoted to process selection, design and operation of a high rate plastics media filter treatment plant for Bass Brewing Ltd., at Runcorn U.K. with special reference to measures to avoid nuisance from the readily putrescible waste waters and an indication of cost.
Substrate Removal Mechanism for Sequencing Batch Reactors
Authors: Orhon D. , Cimşit Y. , Tünay O.
Published: May 2018

All factors affecting substrate removal in sequencing batch reactor types of biological treatment systems should be fully explored to benefit from the many flexibilities of operation they offer. In this paper, a growth limited model is proposed for this purpose and verified by experimental observations. Interpretation of the results enabled a broader description of the process. It also indicated a number of interesting issues requiring further exploration.
Modelling Nitrification in Plant Scale Activated Sludge
Authors: Bliss Peter J. , Barnes David
Published: May 2018

Nitrification performance data from an activated sludge plant was simulated using a simple model based on growth requirements of nitrifiers only and a complete-mix flow pattern. The model best accounted for the plant data under high peak flows and ammonia loadings and confirmed the observation that high peak loadings cannot be fully compensated by increasing the safety factor applied to theoretical mean cell residence time. Difficulties in control of dissolved oxygen and MLSS concentration under high transient loads also adversely affected nitrification. Overall ammonia oxidation rates of the sludge, under the imposed nitrogen and carbon loadings, varied from 2.5 down to 1.3 mg.g−1.hr−1 at mean cell residence times of 3 to A and 9 to 10 days respectively. Adaptation of the model to predictive use requires modification to include overall biomass growth, oxygen relationships and sludge recycle arrangement.
The Treatment and Disposal of Wastewaters from Settlements and Tourist Resorts on the Mediterranean Coast–State of the Art Review
Authors: Tedeschi S.
Published: May 2018

The Mediterranean Sea is in comparison to the Oceans a semi-enclosed sea and represents a concentration basin as the annual water mass brought in by rivers and rainfall is smaller than evaporation. Wastewaters from settlements and tourist resorts contribute comparatively little to the total pollution of the Mediterranean and thus cannot be considered as decisive sources of the waste matter in the sea. The harmful effect of wastewaters from settlements and tourist resorts is noticeable in special local conditions, especially in areas with a poor exchange of the sea water. The most frequent manner of wastewater disposal into the Mediterranean is through its coastal discharge without any previous treatment. In the reconstruction of the existing sewerage systems and in the construction of the new systems, marine outfalls with mechanical treatment as well as short outfalls with biological treatment are applied. In some cases land treatment is applied and wastewater is used for agricultural purposes. Although the sanitation of tne existing discharge and generally the control of the waste matter both require considerable financial means, all the Mediterranean countries are now making an effort to stop the further pollution of the coastal sea.
The Town of Vallauris (French Riviera–An Example of a Coastal Area Sanitation Improvement Project
Authors: Gelas G.
Published: May 2018

The LYONNAISE DES EAUX Company has been managing the sanitation amenities for the town of VALLAURIS GOLFE-JUAN (a summer population of 35.000) since 1974, with a three-fold target:firstly, to arrange for the collection and disposal of the sewage effluent under all circumstances, despite the influx of tourists and without causing any inconvenience to users,secondly,to safeguard the appearance and condition of the beaches during the summer months by canalizing the estuary flow from the valleys and by pumping the runoff water seawards,thirdly, to treat the sewage from the town in order to discharge into the Mediterranean sea a good quality effluent which will not pollute the natural envi ronment.

The targets were reached by using the most modern techniques:

Sewage collection was optimized by installing a computerized management system for the networks, with regular monitored inspections and a preventive cleaning out programme carried out by specialist organizations.

The sewage water was treated in an underwater plant in the Port of GOLFE-JUAN. This plant, which is partially automated and invisible on the site, discharges to the sea water which conforms with the foreseen purity levels at an acceptable operating cost.