bluuebunny/crossref_metadata_2025 huggingface dataset:
Waste Reduction by Process Improvement in the Brightener Intermediates Production
Authors: Sadek S. E. , Lee J. G. , Lund R. B. , McConnell W. W.
Published: May 2018

Stilbene optical brighteners are produced at CIBA-GEIGY in the Mclntosh, Alabama, plant. In producing 4, 4’diaminostilbene-2, 2’disulfonic acid, a major intermediate in the production of these brighteners, a large volume of discharges was generated. These discharges were reduced significantly by a number of process improvements consisting of a yield improvement, reducing the volume of an inert non-recoverable solvent and by replacing a Bechamps iron reduction with a catalytic hydrogenation.
Bulking in Activated Sludge Systems: A Qualitative Simulation Model for Sphaerotilus natans, Type 021N and Type 0961
Authors: Kappeler J. , Gujer W.
Published: May 2018

A biokinetic model which includes a flocforming and three common filamentous microorganisms (Sphaerotilus natans, Type 021N, Type 0961) is introduced. With this competition model which accords with a variety of experimental observations, different bulking phenomena are explained. It is demonstrated that not only the well known facts such as reactor configuration, readily biodegradable substrate and temperature exert a strong influence on bulking behaviour, but also the influent slowly biodegradable substrate as well as inoculating biomass. Therefore it can be concluded that the performance of primary settling tanks plays an important part in bulking.
Phosphorus Release Kinetics in Biofilm Reactors
Authors: Ruiz-Treviño F. A. , González-Martínez S. , Doria-Serrano C. , Hernández-Esparza M.
Published: May 2018

This paper presents the kinetic analysis, using Generalized Power-Law equations to describe the results of an experimental investigation conducted on a batch submerged biofilm reactor for phosphorus removal under an anaerobic/aerobic cycle. The observed rates and amounts of phosphorus release and organic substrate uptake in the anaerobic phase leads to a kinetic model in which these two variables are dependent on each other with a non-linear behaviour and reach equilibrium values in both cases, at different times and are function of rate constants ratio.

The model has a good fit with experimental data except for C uptake at anaerobic contact times longer than four hours, where other kinetics are implied.

Kinetic parameters were obtained with different initial substrate concentrations, anaerobic contact cycles, and type of substrates.
Transformation of Azo Dye AO-7 by Wastewater Biofilms
Authors: Harmer C. , Bishop P.
Published: May 2018

Azo dyes are common contaminants in wastewater. Many are poorly removed by most typical municipal treatment processes. Those which are partially degraded may form toxic intermediates, particularly under anaerobic conditions. Acid Orange 7 (AO-7) is a simple azo dye which is biotransformable. In this study, bulk-phase factors affecting azo bond cleavage of AO-7 in a synthetic municipal wastewater were investigated using lab-scale, rotating drum biofilm reactors. A series of statistically designed experiments were used to characterize the response of the pseudo-steady state biofilms.

A variety of microorganisms from the activated sludge seed for the biofilm were found to be capable of transforming the AO-7. Biofilm removals of AO-7 ranged from 18 to 97%. Two maxima of AO-7 transformation rates were found-one at high bulk-phase dissolved oxygen and low COD removal flux, and another at low dissolved oxygen and high COD flux. No 1-amino 2-naphthol intermediate was detected. The sulfanilic acid intermediate was present at low dissolved oxygen levels. Suspended-phase COD removal was inhibited by AO-7, but the effect was not detected in the biofilm reactor system. AO-7 transformation and biological nitrification interact, but the impact is small.
Biofilm Interactions in Water Reuse Systems: Adsorption of Polysaccharide to Kaolin
Authors: Kanaani Y. M. , Adin A. , Rav-Acha Ch.
Published: May 2018

Interactions of biofilms with dissolved and suspended aquatic matter play an important role in many water work technologies. In order to get a better insight into the driving forces for these interactions, the adsorption of polysaccharides to kaolin clay was studied. The linear adsorption coefficients, obtained at various pH levels, were all substantially lower than those obtained in other studies for humic materials(HA) at pH 6 k=60ml/g for polysaccharide, but for HA k=700ml/g. This is explained in light of the higher hydrophobicity of humic materials. The adsorption coefficient for polysaccharides increases with ionic strength, with the addition of calcium ion, and when the pH is reduced. All these phenomena are explained by conformational changes, of the polysaccharide macromolecules, which result in respective changes in its electric charge. These phenomena are also in accord with the results obtained by determination of the micro-electrophoretic mobility of the clay and clay-polysaccharide particles. For instance, at reduced pH levels the enhanced adsorption was accompanied by decreasing of the negative electrophoretic mobility. Both of these results point to a reduced electric density of polysaccharide and clay-polysaccharide particles when the pH is reduced. All these results may also explain the effect of polysaccharides on the clay coagulation-flocculation by alum.
Biofilm Reactors: A Compact Solution for the Upgrading of Waste Water Treatment Plants
Authors: Sagberg P. , Dauthuille P. , Hamon M.
Published: May 2018

In order to obtain compact plants and to assure a greater treatment reliability, fixed film reactors have been developed. This biofiltration has been applied and proved for over a decade for carbon removal. Today, new applications appear in nitrogen and phosphate removals, which are able to respond to the upgrading of aging waste water treatment plants. Full scale plant results are presented in nitrification. The use of two stages of biofilm reactors (C + N) permits high effluent quality. Chemical phosphate removal and denitrification results obtained on pilot tests are also discussed. Some plants are now been built with such processes.

The VEAS concept, in Oslo, which includes four steps of fixed film reactors is discussed as an example of this present upgrading tendency.
Groundwater Biodenitrification on Sand Fixed Film Reactor Using Sugars as Organic Carbon Source
Authors: Nurizzo C. , Mezzanotte V.
Published: May 2018

Results of a biological denitrification demonstration plant for drinking water, operated for about two years under different conditions, are here summarized. The fixed film anoxic reactor worked downflow at flowrates up to 20 m3/h, using a groundwater with quite variable NO3 concentration (32-52.5 mg NO3/L); thus, nitrate volumetric load Cv range was 0.40-1.45 kg NO3-N/m3 of active bed per day (1.8-6.5 kg NO3/m3·day). These figures were obtained with varied flow (and related hydraulic contact time HCT), partial recirculation of treated water and NO3 addition (fixed HCT); for a short period Cv reached 1.95 kg NO3-N/m3·d, for both NO3 extradosing and flowrate increase. Nitrogen removal rates, using sugar or glucose syrup as organic carbon sources for heterotrophic denitrification, were usually above 80% for the whole biological section (taking into account NO2 oxidation), but NO3 removal rate in the anoxic reactor often reached 95%. For different operating conditions, both substrates gave comparable results, requiring a quite low degree of post-treatments. Heterotrophic denitrification using sugars seems to be a practicable way to solve the problem of increasing NO3 concentrations in drinking water.
Expansion and Upgrading of Columbus, OH WWTPs to Advanced Wastewater Treatment
Authors: Albertson O. E. , Scott R. F. , Stensel H. D. , Okey R. W.
Published: May 2018

In December 1985, the City of Columbus, OH initiated a $220 million program for upgrading capacity and treatment from secondary to advanced wastewater treatment (AWT). The two plants (4990 L/s and 2630 L/s) were required to be fully operational by July 1988. The existing plants had a history of bulking sludges and it was necessary that design/construction proceed concurrently with a laboratory 18-month sequencing batch reactor (SBR) study to evaluate bulking sludge control while producing the required effluent quality of CBOD5, TSS and NH4N of 8,16 and 1 mg/L, respectively. Completion was on schedule and full-scale results paralleled those produced by the SBR sludge. Average effluent concentrations from the larger plant for the 2.5 years of operation were 2 mg/L CBOD5, 5.5 mg/L TSS, 1.5 mg/L TKN, 0.13 mg/L NH4N and 1.1 mg/L TP. The problems resulting from unexpectedly high sludge yields and inadequate sludge transport capacity in the 61 mø clarifiers are discussed and resolutions presented.
Filtration at Bromma Sewage Treatment Plant
Authors: Andersson C. , Tendaj M. , Rothman M.
Published: May 2018

The requirements for purification of the sewage will be more stringent in Sweden. For the three plants in Stockholm - Henriksdal, Bromma and Loudden the proposed limit concentrations for BOD7, total phosphorus and total nitrogen are 10, 0.3 and 15 respectively. A limit value of 0.3 mg/l of phosphorus in the effluent will require a filtration stage.

In this paper results are presented from filter tests at Bromma sewage treatment plant. The tests were carried out during almost two years and included operation of different types of sand dual-media downflow filters and an upflow filter. The filters were tested with respect to sludge accumulation capacity, suspended solids removal and phosphorus removal at different operation conditions including chemical precipitation in the filters.
Analysis of Techniques for Evaluating and Optimizing Existing Full-Scale Wastewater Treatment Plants
Authors: Daigger G. T. , Buttz J. A. , Stephenson J. P.
Published: May 2018

This paper presents an analysis of techniques applied to the evaluation and optimization of nearly 40 full-scale wastewater treatment plants. The techniques evaluated included oxygen transfer analysis by off-gas and hydrogen peroxide techniques, clarifier analysis by stress testing and hydraulic analysis, on-line monitoring, and reactor tracer testing. The results indicate that the process performance of full-scale wastewater treatment units can be measured using these techniques. Advantages exist for off-gas testing when applied to the analysis of low to moderate turbulence diffused air systems. Hydrogen peroxide analysis can be applied to essentially all oxygen transfer systems. Stress testing can be used to quantify the treatment capability of clarifier units; hydraulic analysis can then be used to identify clarifier upgrade opportunities and to quantify the impact of any modifications implemented. On-line monitoring is the most powerful technique tested. It has been used successfully to optimize and improve full-scale treatment plants. Reactor tracer testing can be used to identify upgrade opportunities for full-scale units.
R-D-N Activated Sludge Process
Authors: Kos M. , Wanner J. , Šorm I. , Grau P.
Published: May 2018

The modification of denitrification - nitrification activated sludge process with reaeration of concentrated returned sludge was tested in pilot units with municipal wastewaters at the Prague wastewater treatment plant. The ability of the R-D-N Process to increase the aerobic sludge age with a reduced volume demand was verified. The sludge settling properties were evaluated and the effect of recirculation, simultaneous denitrification and compartmentalization of the denitrification zone was studied. Optimum design parameters of the R-D-N process are suggested.
Fermentation of Raw Sludge and Elutriation of Resultant Fatty Acids to Promote Excess Biological Phosphorus Removal
Authors: Pitman A. R. , Lötter L. H. , Alexander W. V. , Deacon S. L.
Published: May 2018

Research in South Africa has highlighted the dependence of biological phosphate removal mechanisms on the presence of certain minimum concentrations of some readily biodegradable materials including interalia volatile fatty acids. Generation of these compounds was achieved on an experimental basis at the Johannesburg Northern Works by the fermentation of primary sludge either in primary settling tanks or off-line in high rate “acid” digesters.

Elutriation of the volatile fatty acids from the sludge was achieved by recycling the sludge to the influent sewage stream. Significant improvements in phosphate removal were observed and it was decided to design primary sludge treatment facilities to specifically generate the volatile fatty acids.

This paper describes the design philosophy adopted and discusses the preliminary results obtained from the recently commissioned plant at the Johannesburg Northern Works and Bushkoppie plants.
Generation of an Effective Internal Carbon Source for Denitrification through Thermal Hydrolysis of Pre-Precipitated Sludge
Authors: Smith G. , Göransson J.
Published: May 2018

Chemical pre-treatment with highly charged metal salts gives an effluent low in both organic substances and phosphorus. To use pre-precipitation as the first step in sewage treatment improves nitrification in the following biological step. The chemically precipitated sludge contains 75% or more of the organic substances in the raw sewage and can by a hydrolysis process be converted to readily degradable organic substances.

This paper will review experiences from tests with thermal hydrolysis in a full scale plant as well as results from laboratory studies.
Process Design and Operational Modifications of Oxidation Ditches for Biological Nutrient Removal
Authors: Sen D. , Randall C. W. , Grizzard T. J. , Rumke D. R.
Published: May 2018

An oxidation ditch system was modified for excess biological phosphorus and nitrogen removal by connecting two oxidation ditches in series with a small anaerobic cell (10 percent of total reactor volume). The process was operated with 40 to 50 percent of the influent flow entering the anaerobic cell. The rest of the influent was bypassed to the first oxidation ditch. The detention time in the anaerobic cell was adjusted as a process control parameter to develop low oxidation reduction potentials in cold weather or in situations where the influent flow entrained substantial quantities of dissolved oxygen. Average performance levels of 0.6 mg/L for total phosphorus and 4 mg/L for total nitrogen were achieved under temperate conditions. Secondary effluent alkalinity, turbidity and ortho-phosphorus measurements were used as alternative control parameters in addition to dissolved oxygen measurements in the oxidation ditch. Performance testing was carried out at a second oxidation ditch system to estimate the temperature sensitivity of nitrification. It was found that the temperature sensitivity coefficient was only 1.0661/Ceisius in the temperature range between 15 and 25 Celsius.
Northern Europe's Largest Wastewater Treatment Plant in Copenhagen Upgraded to Nutrient Removal
Authors: Hansen J. L. , Nielsen P. S.
Published: May 2018

In connection with the Danish Action Plan on the Aquatic Environment (APAE), the Copenhagen wastewater treatment plants are to be upgraded to nutrient removal. This paper describes the way in which the basis of the decision in respect of design load, choice of treatment process, upgrade type, etc. is achieved.

There are 2 wastewater treatment plants in Copenhagen and it is possible either to upgrade both plants or only to upgrade one and close the other one. It was decided to upgrade both plants and we describe the rationale for this decision.

An extensive effort has been made in order to choose the treatment process. The technical-financial evaluation of various methods will be described, as will the testing of the chosen methods in pilot plants. The design load criteria include the present load, industrial discharges of nutrients, runoff, infiltration, water consumption forecasts, and wastewater temperature.

Finally, the plans for a gradual extension are described. The first stage aims at an extension to the load expected in 1996 when the plant will be put into operation, however, with the possibility to adapt the size of the works during construction, if developments do not correspond to expectations.
New Process Design for Biological Nutrient Removal
Authors: Wanner J. , Čech J. S. , Kos M.
Published: May 2018

A new arrangement of the biological process for efficient COD, N and P removal has been proposed. The process consists of the anaerobic reactor where organic substances from waste water are sequestered into activated sludge, the nitrification reactor where ammonia-rich supernatant is oxidized, and the denitrification reactor where oxidized supernatant is mixed with the activated sludge separated from the anaerobic reactor. Laboratory experiments confirmed favorable characteristics of the proposed system.
Long-Term Sludge Disposal Policy in The Netherlands
Authors: Meijer H. A.
Published: May 2018

The disposal of sewage sludge in The Netherlands will change in the coining ten years from predominantly beneficial use to landfill after optimum volume and solids reduction by technical means. A new regulation prohibits the beneficial use of sludge, even when pollutants are present in very small quantities.

Compared with limit values that are regarded as acceptable in regulations elsewhere in the world, the new Dutch standards are very stringent. Unfortunately the flue gas standards for sludge incineration are also more severe than in other countries, necessarily requiring high tech facilities to achieve these limits. As a result sludge treatment costs will rise immensely in the future. A secondary effect is that studies on the development of alternative technologies for sludge treatment, besides drying, composting and incineration, once again become meaningful. Such alternatives include melting and wet oxidation.
Direct Thermochemical Liquefaction of Sewage Sludge by a Continuous Plant
Authors: Itoh S. , Suzuki A. , Nakamura T. , Yokoyama S.
Published: May 2018

Direct thermochemical liquefaction of sewage sludge was studied as one economical solution to the sludge disposal problem. A continuous plant, which was capable of processing up to 500 kg/d as dewatered sludge, was operated at temperatures of 270-300°C, pressures of 6-12 MPa and holding times of 0-60 min for more than 700 hr without any trouble. Organic materials in sludge were converted into heavy oil with 40-53 %maf yields, and 11-16 %maf of the heavy oil were continuously separated from the reaction mixture by high pressure distillation. Heating value and viscosity of the heavy oil separated were 38 MJ/kg and 0.05 Pa·s, respectively. From the calculation of energy balance ona practical scale, sludge liquefaction process was evaluated as a net energy producer. The disposal of wastewater discharged from sludge liquefaction process was also discussed.
Sorption of Humic Materials onto Inorganic Surfaces for the Mitigation of Facilitated Pollutant Transport Processes
Authors: Liljestrand H. M. , Lo I. M-C. , Shimizu Y.
Published: May 2018

The transport of hydrophobic organic pollutants in groundwaters is facilitated by sorption of these chemicals onto natural organics and transport with these materials. One strategy to mitigate pollutant transport through clay liners and slurry walls is to reduce the transport of the natural organics by enhancing their sorption onto the containment barrier materials. A controlled experimental study of the adsorption of humic acid onto typical inorganic constituents of soils was performed using two types of model solid phases: 1) pure solids (washed Na-montmorillonite clay, amorphous ferrihydrite, and amorphous aluminosilicate gel) and 2) binary combined phases (Na-montmorillonite coated with ferrihydrite or aluminosilicate gel). The combined phases were synthesized for a range of metal to clay mineral ratios. Adsorption tests were conducted to investigate the relative sorption affinity of these solid phases for humic acid. Addition of a ferrihydrite coating was found to increased the sorption of humic acid onto montmorillonite clay.
Treatment of Wastewater with High Energy Electron Beam Irradiation
Authors: Farooq S. , Kurucz C. N. , Waite T. D. , Cooper W. J. , Mane S. R. , Greenfield J. H.
Published: May 2018

The objective of this study was to determine the effectiveness of high energy electron beam irradiation in the disinfection of wastewater, and removal of organic matter through measurement of BOD and COD values. The raw wastewater and secondary effluents were transported in a 22.7m3 tank truck to the research facility built at the Virginia Key Wastewater Treatment Plant, Miami, Florida. The facility is equipped with a 1.5 MeV, 50 ma electron accelerator capable of treating the wastewater at a volumetric flow rate of 7.57 l/sec. Some preliminary disinfection was also carried out using a 60Co gamma radiation source. Removal of coliphage, total coliforms, and standard plate counts was found on the order of two to three orders of magnitude in raw wastewater. Gamma irradiation gave slightly better inactivation. However, in all cases it was found that coliphage is more resistant than the other two organisms investigated. Twenty to 30 percent removal of BOD was observed in the case of raw wastewater, however, no significant change was observed in removal of COD.
The Deposition and Erosion of Sediments in Sewers
Authors: Ashley R. M. , Wotherspoon D. J. J. , Goodison M. J. , McGregor I. , Coghlan B. P.
Published: May 2018

The problems caused by sediments in sewers are now universally acknowledged. A number of countries have set up comprehensive programmes to study all aspects of sewer sediments; their occurrence, nature and movement. In the UK the Water Research centre and others have funded a comprehensive study of the sediments in the Dundee sewer system. The rate of sedimentation and the yield strength of the sediments have been investigated and considered in terms of the subsequent erosion by increasing flows. The sediments have been found to be cohesive in nature and highly resistant to erosion in the main interceptor sewer, whereas in the trunk sewers the sediments are more granular and less cohesive in nature. A sewer classification system is suggested which is based on physical characteristics, and also relates to the nature of the sediments deposited, and the bed-load material conveyed close to the bed.
Methods of Estimating the Discharge of Gross Solids from Combined Sewer Systems
Authors: Jefferies C.
Published: May 2018

Visible pollution discharged from two combined sewer overflows were studied using passive Trash Trap devices and the UK Water Research Centre Gross Solids Sampler. Relationships are presented for the number of visible solids and the mass of gross solids discharged during an event. The differences in the behaviour of the overflow types are reported on and they are categorised using the Trash Traps.
Validation of On-line Respiration Meter and its Applications by Computer Simulation
Authors: Kim C-W. , Spanjers H. , Klapwijk A.
Published: May 2018

An on-line respiration meter is presented to monitor three types of respiration rates of activated sludge and to calculate effluent and influent short term biochemical oxygen demand (BODst) in the continuous activated sludge process. This work is to verify if the calculated BODst is reliable and the assumptions made in the course of developing the proposed procedure were acceptable. A mathematical model and a dynamic simulation program are written for an activated sludge model plant along with the respiration meter based on mass balances of BODst and DO. The simulation results show that the three types of respiration rate reach steady state within 15 minutes under reasonable operating conditions. As long as the respiration rate reaches steady state the proposed procedure calculates the respiration rate that is equal to the simulated. Under constant and dynamic BODst loading, the proposed procedure is capable of calculating the effluent and influent BODst with reasonable accuracy.
Ozonation for Reuse of Gold Mine Service Water
Authors: van Leeuwen J. , van der Westhuizen H. T.
Published: May 2018

Gold mine service water is primarily intended for cooling and dust suppression. Faecal pollution makes disinfection imperative as the workers prefer this chilled water to potable water. Ammonia and nitrite formed by the partial biological oxidation of ammonia lead to an excessive disinfectant demand. Ozo-nation on a 3.6 Mi/d scale proved successful in oxidizing nitrite with simultaneous good disinfection. Ozone transfer efficiencies of more than 96% could be achieved within a deep U-tube compared with 80-90% using a bubble column and 73-80% using an in-line mixer. A unit process capable of introducing 7 mg/ℓ ozone on a 50 Mℓ/d scale would cost US $1.5 million and US $75 000 per year to operate compared with an estimated cost of $1 million per annum for either chlorine or chlorine dioxide.
Modelling Nematode Egg Elimination in Wastewater Stabilization Ponds
Authors: Saqqar M. M. , Pescod M. B.
Published: May 2018

The paper analyses data on intestinal nematode egg numbers (NNE) taken over a 30-month period in a large wastewater stabilization pond system. The retention time of 8-10 days suggested by WHO as the treatment expected to achieve an effluent with less than 1 nematode egg per litre was not supported by the results. A model has been developed to describe the elimination of nematode eggs(NNE) in ponds. According to this model, 14 days theoretical retention time is required to achieve the above criterion in the Alsamra pond system. The importance of the inflow jet velocity in influencing effluent quality, in terms of NNE, has been demonstrated.
The Effect of Sunlight on Faecal Coliforms in Ponds: Implications for Research and Design
Authors: Curtis T. P. , Mara D. D. , Silva S. A.
Published: May 2018

Empirical and theoretical models of the effect of light on faecal coliforms (FC) in waste stabilization ponds are used to show that: (i) light can only have an impact on FC if complemented by high dissolved oxygen (DO) concentrations and a high pH; (ii) the tendency of algae to impede light penetration is offset by their ability to raise the pH and DO; and (iii) that visible light is more important than UV. Therefore the DO concentration and pH should be included in models of the effect of light in ponds. In the absence of light, pH values < 9.3 may have less impact than previously reported. The implications for design and research are discussed.
Effect of Physicochemical Variables on Algal Autoflotation
Authors: Lee S.-I. , Koopman B. , Lincoln E. P.
Published: May 2018

Combined chemical flocculation and autoflotation were examined using pilot scale process with chitosan and alum as flocculants. Positive correlation was observed between dissolved oxygen concentration and rise rate. Rise rate depended entirely on the autoflotation parameters: mixing intensity, retention time, and flocculant contact time. Also, rise rate was influenced by the type of flocculant used. The maximum rise rate with alum was observed to be 70 m/h, whereas that with chitosan was approximately 420 m/h. The efficiency of the flocculation-autoflotation process was superior to that of the flocculation-sedimentation process.
The Ohio River Valley Water Sanitation Commission's Toxic Substances Control Program for the Ohio River
Authors: Tennant P. A. , Norman C. G. , Vicory A. H.
Published: May 2018

The Ohio River Valley Water Sanitation Commission (ORSANCO) is an interstate agency created in 1948 to administer a state compact which calls for the abatement of water pollution in the Ohio Valley. Since 1975, ORSANCO has conducted routine monitoring programs to detect the presence of toxic chemicals in the Ohio River and in fish taken from the river. Such information is particularly important as the Ohio River, a major river in the United States, serves as a water supply to over three million people and is used extensively for recreational purposes. The monitoring results have shown several problems: contamination of fish tissue by PCBs and chlordane, concentrations of certain metals which exceed chronic aquatic life criteria in 10 to 25 percent of the samples analyzed, and levels of certain volatile organic compounds which exceeded criteria established to prevent one additional cancer per one million population in almost half the samples analyzed.

In 1986, the Commission initiated a Toxic Substances Control Program which was designed to identify sources of the toxics problems and prescribe corrective actions. Because of the multitude of potential sources of toxics along the Ohio, the river was divided into seven segments for intensive study. To date, studies have been initiated on four segments. In addition, special topic studies have been conducted on the river as a whole to address the suitability of the river as a source of drinking water, trends in parameter levels, and the relationship between surface and ground water quality.

Findings to date:Point source discharges to the river do not cause widespread toxics problems.Nonpoint sources, including urban runoff and contaminated ground water, are significant sources of toxics to the river.Levels of certain toxics in tributaries are also an important source.Under “normal ” situations (i.e., excluding spills), the Ohio River provides a suitable source water for public supply after appropriate treatment.Levels of many metals and volatile organic compounds have decreased over the past 10 years.
The Role of Computer Modeling in Combined Sewer Overflow Abatement Planning
Authors: Roesner L. A. , Burgess E. H.
Published: May 2018

Increased concern regarding water quality impacts from combined sewer overflows (CSOs) in the U.S. and elsewhere has emphasized the role of computermodeling in analyzing CSO impacts and in planning abatement measures. These measures often involve the construction of very large and costly facilities, and computer simulation during plan development is essential to cost-effective facility sizing. An effective approach to CSO system modeling focuses on detailed hydraulic simulation of the interceptor sewers in conjunction with continuous simulation of the combined sewer system to characterize CSOs and explore storage-treatment tradeoffs in planning abatement facilities. Recent advances in microcomputer hardware and software have made possible a number of new techniques which facilitate the use of computer models in CSO abatement planning.
Private Capital Participation: Choices and Constraints
Authors: Kinnersley D.
Published: May 2018

The scope for involving private capital participation in wastewater treatment and pollution control is attracting attention in a number of countries. After noting briefly some influences giving rise to this trend, this paper discusses frameworks in which such participation may be developed.

In some aspects, there are choices available and it is essential to shape the private participation appropriately to the community's situation and problems, with due recognition of the hazards also involved. In other aspects, policy choices are more constrained, and there are requirements which it is suggested all private participation frameworks should provide for as clearly as possible.

Effective private participation generally depends on re-designing and strengthening the role of government as the scale of its former role is reduced. Getting this re-design of the government role right is at least as important as making appropriate choices for format of private participation.
Treatment of a Landfill Leachate Containing Refractory Organics and Ammonium Nitrogen by the Microorganism-Attached Activated Carbon Fluidized Bed Process
Authors: Iwami N. , Imai A. , Inamori Y. , Sudo R.
Published: May 2018

The microorganism-attached activated carbon fluidized bed (MAACFB) process was applied to treat a landfill leachate containing refractory organics and a high concentration of ammonium nitrogen. The MAACFB process removed about 60 % and 70 % of refractory organics and nitrogen, respectively, from the landfill leachate simultaneously and steadily over a more than 700 days of operation period. A mass balance on organics around the MAACFB process revealed that more than 90 % of the removed organics may be biodegraded. It was suggested that the MAACFB process is highly effective in biodegrading the refractory organics in landfill leachate.
Channel Experiments on Coastal Water Purification by Porous Bed Using Crushed Stones
Authors: Hosokawa Y. , Ootsuki T. , Niwa C.
Published: May 2018

Large-scale model channels (30m long × 1m wide × 1.3m deep × 6 channels) were constructed for contact purification experiments for coastal saline water. Each channel was filled with crushed stones which were expected to be coated with natural biofilm. Effects of sedimentation and biological oxidation were observed for different hydraulic retention time (HRT: 1-5 hours) and different stone size (mean d: 10-100 mm). Hydraulic characteristics were also measured. The following was clear after five months' observation in autumn and winter, (a) biofilm was developed for saline (S: 1-2 %) and low COD (COD: 1-5 mg/l) influent, (b) SS was removed by 50-60 % though TOC by 10-20%, (c) effluent quality was clearer with longer HRT and smaller stones, but total removed weight was maximum at the channel of shortest HRT due to the high hydraulic loading(12m3) (d) permeability ranged between 5-20cm/s for bare stones and became smaller as clogging developed, (e) inclination of water surface was a good index for clogging detection.
Anaerobic-Aerobic Wastewater Treatment Plant of a Potato Chips Factory
Authors: Austermann-Haun U. , Seyfried C. F.
Published: May 2018

The described full scale wastewater treatment plant of the potato chips factory is working with a two-stage anaerobic pretreatment followed by an aerobic purification with nitrogen and phosphorus removal. Extraordinary elements of the plant are the fixed-film methane reactor and the trickling filter used as a cooling element between the anaerobic stage and the activated sludge system. A sludge blanket was built up underneath the swimming support media of the fixed-film methane reactor. During the first year of operation the energy profit by methane production was 1 056 000 kWh, which is 50 % of the whole energy consumption of the wastewater treatment plant.
Removal of Salmonella, Streptococci and Coliforms in Pig Breeding Effluent by Anaerobic Mesophilic Digestion
Authors: Duarte E. A. , Mendes B. , Oliveira J. S.
Published: May 2018

Removal of bacteria has been followed in a continuously stirred reactor working at 37 °C and 54.9 °C on pig breeding effluents. The reduction of total and faecal coliforms, total and faecal Streptococci and Salmonella was extremely important, especially under thermophilic conditions.

Biomethanisation may be considered as an efficient treatment for organic load reduction and biogas production, and also for nutrients recovery and for pathogens removal, being an important contribution for a global and integrated scheme of pollution control and environmental protection.
Growth of Thiosphaera Pantotropha in a Continuous-Flow Stirred Tank Reactor
Authors: Arts P. A. M. , Robertson L. A. , Bos P. , Kuenen J. G.
Published: May 2018

Two reactor types, a fluidized bed reactor and a RotoTorque reactor, were tested for their suitability as model systems for immobilization studies of pure cultures of T. pantotropha. T. pantotropha is a very interesting organism for waste water treatment, because of its ability of simultaneous aerobic denitrification and heterotrophic nitrification. Results indicate that the RotoTorque reactor is a more attractive model system for immobilization studies of T. pantotropha than the fluidized bed reactor used in this study. Using the RotoTorque reactor, studies on immobilized growth of T. pantotropha are currently being performed under anaerobic conditions. At a dilution rate of 1.2 h−1 (about four-fold higher than µmax under the experimental conditions) rapid attachment of T. pantotropha can be reproducibly observed. Within a couple of days, the cultures reach a 'steady state', where growth of the attached biomass is balanced by erosion. Microscopic investigations of the attached biomass indicated that T. pantotropha forms microcolonies rather than homogeneous biofilms.
Potassium and Magnesium Requirements for Enhanced Biological Phosphorus Removal from Wastewater
Authors: Rickard L. F. , McClintock S. A.
Published: May 2018

The role of potassium (K) and magnesium (Mg) in enhanced biological phosphorus removal (EBPR) by activated sludge was studied using a bench-scale continuous-flow A/O system. A synthetic wastewater containing all the nutrients required for EBPR was used as the influent feed for the control phase of the experiment. The influent feed to the test phase of the experiment was changed to totally limit specific cations. The results clearly indicated that both K and Mg were absolutely required for successful EBPR. Failure of EBPR occurred when either K or Mg were eliminated from the influent. The molar ratio of K:P during anaerobic release and aerobic uptake was observed to be 0.22 mol/mol, while Mg:P was 0.30 mol/mol. Calcium was not required for successful EBPR. Neither calcium, iron, nor sodium were co-transported with phosphorus during release and uptake.
Struvite (MgNH4PO4·6H2O) Solubility and Its Application to a Piggery Effluent Problem
Authors: Webb K. M. , Ho G. E.
Published: May 2018

Struvite (MgNH4PO4·6H2O) solution chemistry was studied in order to understand a struvite scaling problem which exists in the pipe network of a series of 4 effluent lagoons at a piggery.

The conditional solubility constant (PS=SMG·SNH3−N·SPO4−P, equilibrium S values (M)) was determined over a range of pH values (6.8-8.5) and solution concentrations of Mg, NH3−N and PO4−P close to field conditions, and at a temperature of 30°C.

A comparison of field and laboratory data indicates struvite precipitates from the second lagoon onwards. The solubility data obtained also indicate potential for precipitation as a method of nutrient removal from wastewaters.
Full-Scale Cyclic Activated Sludge System Phosphorus Removal
Authors: Goronszy M. C.
Published: May 2018

The performance of three full-scale cyclic activated sludge facilities, operated for biological phosphorus removal is demonstrated. The facilities are operated without formal mixed anoxic or anaerobic sequences in a variable volume mode. The system is independent of fill-ratio operation for filamentous sludge bulking control.
Anoxic, Zero-Headspace Titrations of Landfill Leachate
Authors: Sawyers D. E. , Dentel S. K.
Published: May 2018

Leachate samples from an operating landfill were sampled periodically using a closed-system anoxic technique to avoid exposure of leachate to air. Anoxic, zero-headspace titrations were then performed on these samples. Buffering capacity results show the importance of this technique in proper characterization of leachate in-situ. Results, and their comparison to predicted curves using SURFEQL, a multiple-component chemical equilibrium program, enable identification and quantification of some buffering components, but buffering components around pH's 5 and 8 have not been conclusively identified or modelled.
ION Exchange Characterisation of Modified Zeolite
Authors: Cerjan-Stefanovic Š , Kaštelan-Macan M. , Filipan T.
Published: May 2018

Isomorphous substitution of phosphorus into a natural zeolite affords the possibility to change the overall framework charge from negative to positive. The substances so created should be used for purification of waste waters.

The work describes the preparation of phosphated zeolite, their characterisation and examples of their anion exchange of NO3 on observed in deionized water, drinking water and in the solution containing varying amounts of nitrate.
Nonionic Surfactant Sorption onto Soil
Authors: Liu Z. , Edwards D. A. , Luthy R. G.
Published: May 2018

Experiments in batch soil/aqueous systems were conducted to evaluate the sorption onto soil of four nonionic surfactants. At bulk solution surfactant concentration less than the respective critical micelle (aggregate) concentration (CMC or CAC), sorption can be assessed using a surface tension technique and can be characterized with a Freundlich isotherm. At bulk solution surfactant concentrations equal to or greater than the critical concentration, sorption of the micelle-forming surfactants can be assessed by a spectrophotometric technique with an azo dye and had a constant value; sorption of the lamellae-forming surfactant can be assessed by a chemical oxidation technique and, however, appeared to be an increasing function of the surfactant dose.
Evaluation of Landfill Effects on Aquatic Ecosystems Using Benthic Macro-Invertebrates
Authors: Cingolani L. , Morosi A.
Published: May 2018

The aim of this work was to verify the effectiveness of benthic macro-invertebrate observation in providing information about the effects of a landfill on an aquatic ecosystem. A significant difference between upstream and downstream communities from landfill drainage area was found. The adopted taxonomic level was sufficient to reach our object.
Fine Bubble Aeration Using a High Density Diffuser System
Authors: Thatcher K.
Published: May 2018

Current developments with the activated sludge processes with highly concentrated effluents highlight the requirement to (a) reduce energy usage (b) promote the production of high quality effluent.

Having observed the efforts being made to improve plant performance we became aware that current methods had to be improved. It was also noted that a period of stagnation had occurred in the development of effective aeration systems.

Improved aeration methods are needed which would allow for oxygen transfer efficiencies to be greater than 2kg/kWh. Such oxygen transfer rates should be continually variable in line with the oxygen demand prevailing at any given time.

In our study of activated sludge plants we found that operational and electrical/mechanical maintenance was proving to be time consuming and very costly.

With these problems in mind we have designed and developed the Fine Bubble High Density Diffuser System.
Kinetics of Polymeric Substrate Removal by Activated Sludge: Hydrolysis of Polymers is the Rate-Determining Step
Authors: Ubukata Y.
Published: May 2018

A large portion of organic matter in primary effluent is polymers such as proteins and polysaccharides, and heterotrophic bacteria can directly take up only monomers such as amino acids and glucose that are produced from polymers by hydrolysis. Therefore it is assumed that the hydrolysis of polymers to monomers is the rate-determining step in activated sludge process. Activated sludges were acclimated to dextrin or peptone, and polymers (dextrin or peptone) and monomers (glucose or a mixture of free amino acids) were used as substrates for kinetics tests. Monomers were removed linearly, and the removal of polymers followed pseudo first order kinetics on the other hand. The removal rate of monomers was higher than that of polymers. The only one difference between polymer and monomer is whether glycosidic or peptide bond exists in molecule or not. It was, therefore, verified that the hydrolysis of polymer to monomer was the rate-determining step in activated sludge process. The removal of polymers followed apparently first order kinetics at higher F/M ratios, but followed nth (n>l) order kinetics at lower F/M ratios.
Suppressive Effects on Filamentous Bulking by Addition of Corn Cob Flour and Divalent Metal Ions
Authors: Iyo T. , Yoshino T. , Ohno S.
Published: May 2018

We investigated the suppressive effects on filamentous bulking by addition of grinding flour of corn cob (corn cob flour abbreviated to CCF), agriculture waste, and the divalent metal ions. When 1000 mg.L−1 of activated sludge loading with 30 % of CCF was operated by a continuous process, we obtained a microbial coagulation of which nucleus was formed by CCF with good settling character and high density in spite of use the substrate of which the main element was glucose caused easily the filamentous bulking. This effect, further, was increased with addition of Ca2+ ion. From SEM observation, we found few filamentous microorganisms but cocci and short rods dominant on this surface of CCF which possessed good settling character, i.e., 20-30 ml·g−1 of sludge volume index (SVI) and 2-6 cnrmin.−1 of the interfacial settling velocity. It was characteristic that many Arcellasp., Protozoa, adhered to the surface of CCF with Ca2+. From these results, it was estimated that Ca2+, divalent metal ion, promoted the cross-linking act among cytoplasmic membranes charged negative and increased the affinity between CCF and microorganisms.
Investigations on Activated Sludge Microfauna and Treatment Plant Disfunctions
Authors: Cossignani M. , Cingolani L. , Giacché L. , Miliani R.
Published: May 2018

Factorial analysis was applied to data from a series of 24 samples collected in an activated sludge treatment plant from October 1990 to April 1991. Relationships between process parameters and protozoans suggested that Epistylis plicatilis aboundance is related to the best conditions of BOD removal. Moreover the presence of Litonotus fasciola related to a poor floc settling.
Sequencing Batch Reactors - An Overview
Authors: Norcross K. L.
Published: May 2018

Sequencing Batch Reactors (SBR's) offer many advantages and few disadvantages to the wastewater treatment process selection. Due to the relatively recent surge of interest in SBR's, few plants have been on-line long enough for Engineers to have developed a thorough understanding of all design aspects and considerations. The author has been involved directly in the design, equipment supply, start-up and operation of almost 60 SBR's of all sizes. About two thirds of the installations are municipal and one-third of these installations are industrial sites involving wastes from food processors, dairies, distilleries, petro-chemical manufacturers, landfill leachate, tanneries, Government munition plants and pharmaceutical manufacturers. The control of filamentous bulking has also been excellent with SBR's.

This paper will consider the mechanical, process and control aspects for design of an SBR. The mechanical aspects will include HRT and basin sizing, selection of aeration equipment and effluent decanters. The process parameters discussed will include loading rates and F:M considerations, MLSS concentration, oxygen requirements and D.O. uptake rate, flow proportional aeration, the benefits of an anoxic fill cycle, and finally, nutrient removal. Control considerations are briefly discussed.
Determination of Some Kinetic Parameters by Respirometry
Authors: Roš M. , Dular M.
Published: May 2018

Individual kinetic parameters such as BOD, biodegradation of wastewater, reaction time, maximal substrate rate can be determined by respirometry. For the determination of main respirometric parameters (STBOD, BODr, reaction time, etc.) overall oxygen transfer coefficient, KLa, is needed. This parameter can be determined with dynamic method in an open respirometer at limited conditions (constant temperature, constant stirring conditions).

It was found out that KLa is dependent upon concentration of the activated sludge; it can be determined with about 2% of relative standard deviation.

The objective of our research work was determination of maximal exogenous oxygen uptake, re max and maximal substrate utilisation, µmax, which is very important kinetic parameter at wastewater treatment. These parameters show us the maximal substrate (wastewater) utilisation for appointed activated sludge.