bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicted Restoration of the Surrounding Marine Environment after an Artificial Mercury Decontamination at Minamata Bay, Japan - Economic Values for Natural and Artificial Processes
Authors: Kudo A. , Miyahara S.
Published: May 2018

More than 35 years ago, an accident surfaced because of human misery at Minamata Bay, Japan. By 1960, more than 100 people suffered (mortality rate was over 20%) by eating fish containing methylmercury. By 1987, 1742 people were identified with this Minamata disease. The methylmercury along with inorganic mercury was released from a nearby chemical factory into the Bay, contaminating not only fish but the entire ecosystem including the bottom sediments. The amount of mercury deposited in the sediments was considered to be 150 tons. The Japanese Government initiated, in 1984, a decontamination project vacuuming the contaminated sediments into a sealed area creating a reclaimed land mass of 582,000 m2. The movement of the mercury deposited in the Bay outward to Yatsushiro Sea, was observed during the last 16 years by sampling and analyzing the surface sediments of Yatsushiro Sea. Since 1975, the deposited mercury moved continuously outside from the Bay at an annual rate of 3.7 tons. The initiation of the artificial decontamination (over $500 million in US funds), however, changed the pattern of mercury movement and drastically reduced its contents with a half-life of 1.83 years. Since 1985, the amounts of mercury in the surface sediments of Yatsushiro Sea have been decreasing dramatically with a half-life of 9.5 years. If this present trend of decrease continues, it becomes possible to predict that the Sea would be completely restored by 2011 AD. Another interesting observation was a historical storm in 1982, which cleaned-up the surface sediments of Yatsushiro Sea with a half-life of 2.76 years. If the clean-up effect of the natural processes in Yatsushiro Sea was compared to the artificial one, its economic value was calculated to be $96 million (US funds). Any decontamination attempt for polluted sites should consider a combination of the natural and artificial decontamination processes for economic reasons.
A Preliminary Study of the Micronucleus Test by Acridine Orange Fluorescent Staining Compared with Chromosomal Aberration Test Using Fish Erythropoietic and Embryonic Cells
Authors: Ueda T. , Hayashi M. , Ohtsuka Y. , Nakamura T. , Kobayashi J. , Sofuni T.
Published: May 2018

The micronucleus test using fish peripheral blood has been introduced to assess the contamination of water with some mutagenic chemicals. The applicability of the micronucleus test erythrocytes combining acridine orange (AO) fluorescent staining to fish was evaluated as compared with the chromosomal aberration test method. Peripheral blood cells were smeared on glass slides, fixed with methanol, and stained with AO. AO fluorescence microscopy could differentiate between young and mature erythrocytes, thus only young erythrocytes could be observed. The sensitivity to detect the clastogenic effects of chemicals could be increased especially after acute treatment. Mitomycin C (MMC), a potent clastogen, was injected intraperitoneally to gold fishes and rose bitterlings at doses of 2, 4, 10, and 20 mg/kg. The mean frequencies of micronucleated young erythrocytes of three gold fishes peaked 3 days after treatment at 4 mg/kg body weight. Rose bitterlings showed maximum response of micronucleated young erythrocytes and chromosomal aberrations 2 days after treatment with 4 mg/kg of MMC. The cells from embryos of rose bitterlings and metropolitan bitterlings were used for the micronucleus and the chromosomal aberration test. The cultured cells established from fins of rose bitterlings were also used as materials of the chromosomal aberration.
A New Index Rec-Volume for the Evaluation of DNA Toxic Pollution in the Water Environment
Authors: Matsui S. , Semba N. , Matsuda T. , Yamada H.
Published: May 2018

Bacillus subtilis rec-assay was applied to water samples from Lake Biwa and the Yodo River which provide municipal drinking water sources for 14 million people in the basin. DNA toxicity of the water samples concentrated with XAD-2 resins, was evaluated in terms of Rec-volume. DNA toxicity increased toward downstream indicating strong potential of DNA toxicity almost equivalent to that of standard substances such as MNNG, 4NQO etc.. Micropollution of hydrophobic substances needs more attention for the safety of ecosystems as well as drinking water. The rec-assay also provided information on cytotoxicity of the hydrophobic micropollutants to the test bacteria.
Seasonal Variation and Stability of Chlorinated Organic Mutagens in Drinking Water
Authors: Kinae N. , Sugiyama C. , Nasuda M. Y. , Goto K. , Tokumoto K. , Furugori M. , Shimoi K.
Published: May 2018

Seasonal variation of several chlorinated compounds, which are mutagenic and/or carcinogenic, in drinking water of Japan was examined by using a gas Chromatograph equipped with an electron-capture detector and a gas Chromatograph connected with a mass spectrometer. Water samples collected from 10 different points were submitted to physico-chemical analysis, and then subjected to the determination of chlorinated compounds. Potassium permanganate consumption values showed high scores in summer and autumn at all sampling points. Trihalomethanes(CHCl3, CHBrCl2, CHBr2Cl, CHBr3) had a tendency to show high values in summer at the urban areas. On the other hand, a new potent mutagen, 3-chloro-4-dichloromethyl-5-hydroxy-2-(5H)-furanone(MX) did not show any characteristic pattern in all seasons. The stability of MX under certain physical and biological conditions was also investigated. The mutagenic activity of MX on Salmonellatyphimurium TA100(-S9mix) decreased with increase of pH and temperature of the incubation solution. When MX was treated with human serum, the mutagenic activity disappeared in a short time. But, there was no change of the activity by treatment with human saliva.
An Integrated Modelling Study to Upgrade the Sewerage System of a Coastal Town
Authors: Delo E. A. , Kellagher R. B. B.
Published: May 2018

Two complementary methods for the design of storage capacity in an upgraded sewerage system in relation to compliance with the Bathing Water Directive are described. A ten year record of hourly rainfall depths was analysed to give the daily maximum depth of rainfall for durations of 1 h, 2h, 4h, 6h, 8h and 12h. The rainfall events that exceeded the five year design storm were removed. The first method comprised selecting the largest of the second worst storms in each of the ten years and using those as design storms to compute the storage volume required for the upgraded sewerage system. The second produced an analysis of the probability of compliance against storage volume in the upgraded sewerage system. This involved consideration of the probability of an overflow event occurring on a sampling day, statistical analysis of the daily maximum depths of rainfall, and the determination of rainfall depths and durations for a range of storage volumes. The probabilistic method was considered to provide a useful aid to decision makers.
Theoretical and Practical Approach to the Disinfection of Municipal Waste Water Using Chlorine Dioxide
Authors: Dernat M. , Pouillot M.
Published: May 2018

Disinfection efficiency of urban waste water treatment depends on treated water characteristics and receiving medium. The amount of chlorine dioxide (2 to 5 mg/l) needed for a given effluent is relatively low due to its high effectiveness against many microorganisms.

No typical by-products, such as hypobromites, trihalomethanes, chloramines, are obtained with chlorine dioxide.

In a case study, bacterial analyses show that the treatment respects the limit of 2000 fecal coliforms per 100 ml of treated water and contributes to maintain the beach water quality of Deauville and Trouville in France.
Peracetic Acid Disinfection of Secondary Effluents Discharged off Coastal Seawater
Authors: Lefevre F. , Audic J. M. , Ferrand F.
Published: May 2018

Peracetic acid (PAA), a well known powerful antimicrobial agent in hospitals and in agribusiness (Fraser, 1986), has recently been used to disinfect urban effluents. It appears to be highly competitive against chlorine (Audic, 1990; Baldry, French, Slater and Desprez, 1990; Giodani, Iacoponi, Polidori, 1989), the most widely used disinfectant for sewage disposal.

As PAA is a new biocide, not much quantitative data is available on its action against the faecal indicator bacteria and viruses.

An on-site experimental study investigated the disinfectant action of PAA against these indicator bacteria and viruses as well as against Salmonella and enterovirus. To complete this study we will test its action on suspended solids to find out whether there is regrowth of the microorganisms after treatment.

Multi-factor analysis in terms of criteria like inactivation efficiency, safety environmental impact, and cost will be used to compare PAA to chlorination and ozonation, the most commonly used techniques.
Sources, Cycling and Fate of Contaminants in Chesapeake Bay
Authors: Sanders J. G. , Riedel G. F.
Published: May 2018

In order to predict and control the impacts of contaminants to coastal ecosystems like the Chesapeake Bay, we must first understand the geochemical, physical, and biological factors that control contaminant transport, transformation, uptake, and fate. Some processes exert control over broad groups of contaminants; the importance of others varies with specific contaminants. Many of these processes are well known and are amenable to predictive modeling, while others are less well understood and require further attention and research. Most important for the future protection of the Chesapeake Bay, and other coastal ecosystems, will be a coordinated approach (both in the research that must be conducted and in the management decisions that must be made), linking scientists of many disciplines with those charged with ecosystem protection.
Environmental Consequences of the Gulf War in Kuwait: Impact on Water Resources
Authors: Literathy P.
Published: May 2018

As a result of the Iraqi occupation and the armed conflict in Kuwait 6 to 8 million barrels of crude oil were spilled into the marine environment, and about 2 to 3 million barrels of crude oil, burnt and unburnt, were being emitted daily during about 300 days into the environment from the burning or gushing oil wells. International efforts of UN agencies and other organizations from, the region and outside started immediately to assess the extent of the environmental pollution and to mitigate the adverse effects. In addition to the public health concerns of the air pollution caused by the burning wells, long-term environmental risk should be considered as a result of the oil spill into the marine and coastal environment, and the atmospheric fall-out, e.g., acid rain and petroleum related compounds associated with airborne particulates, in the marine and terrestrial areas. Particularly serious contamination of the desert ecosystem occurred around the damaged oilfields in Kuwait. The deposited crude oil and airborne particulates in the terrestrial areas may also affect the ground-water aquifer. Air quality, marine and desert soil pollution surveys provided data for a preliminary assessment and helped the formulation of mitigation and rehabilitation programmes, however, implementation of an integrated survey programme will ensure the final impact assessment on the environment, particularly on the marine and subsurface water resources.
Difference in Transport Behavior between Aliphatic and Aromatic Petroleum Vapors in Unsaturated Soil
Authors: Li C. , Voudrias E. A.
Published: May 2018

Unsteady state multicomponent vapor transport experiments in large (10.5 cm × 100 cm) columns packed with dry and wet soil and dry sand were used to evaluate the difference in transport behavior between aliphatic and aromatic petroleum vapors. The experimental data were analyzed using a modified diffusion equation accounting for vapor sorption and vapor partitioning into the soil moisture. Excellent agreement between the diffusion model and the experimental data was observed for all vapors studied in dry sand and dry soil and for aliphatic vapors in wet soil. However, a poor agreement was observed between the model and the aromatic vapors in wet soil. This was attributed to mass transfer limitation and violation of the local equilibrium assumption used to describe aromatic vapor partitioning into the soil moisture. Significant reduction in retardation factors for all vapors was observed in wet soil due to sorption competition by water molecules, but aromatic retardation factors were higher than the aliphatic ones, because of their high solubility and partitioning into the soil moisture.
Design and Implementation of Pilot Scale Surfactant Washing/Flushing Technologies including Surfactant Reuse
Authors: Clarke A. N. , Mutch R. D. , Wilson D. J. , Oma K. H.
Published: May 2018

Chemicals with low solubility, volatility, and biodegradability can be very hard to treat in soils. These chemicals may however by addressed by surfactant supplemented technologies. PCBs are a prime example of difficult chemicals and were used frequently in the studies. The surfactant enhances the solubility of the chemicals, therefore effecting their desorption and more efficient treatment. ECKENFELDER INC. has completed laboratory scale experiments simulating in situ/ex situ surfactant treatment of various types of chemicals, singly and in combination, and has built a pilot scale unit for the surfactant treatment of contaminated soils. The pilot scale system includes surfactant recycle and reuse of an anionic surfactant, sodium dodecyl sulfate, SDS. The resultant volume of contaminants is reduced many fold, thus consistent with US regulatory requirements as well as reducing final disposal costs. In addition to the pilot scale unit, studies were made on the impact of non equilibrium (e.g., desorption, diffusion, etc.) effects on treatment efficiency as well as developing “real time” chemical analyses of PCBs in SDS solution. A mathematical model has also been developed which assists with design/performance assessments.
The Effect of Oxidation-Reduction Potential on the Biotransformations of Chlorinated Hydrocarbons
Authors: Doong R.-A. , Wu S.-C.
Published: May 2018

Two batch experiments with acetate as the primary substrate and different combinations of chlorinated hydrocarbons as the secondary substrate were carried out to evaluate the effect of the redox potential of the environment on the biotransformations of chlorinated hydrocarbons. In both single and mixed contaminant(s) systems, biotransformations of 100 µg/L of tetrachloroethylene (PCE) and carbon tetrachloride (CT) were observed, but that of 1,1,1-trichloroethane(1,1,1-TCA) was not observed within 108 days. Chlorinated hydrocarbons acted as electron traps and scavenged the electrons when they underwent reductive dechlorination. Adequate activity of free available electrons is necessary for chlorinated hydrocarbons to undergo reductive dechlorination. The environment with low redox potential has relatively strong electron activity and therefore facilitates the biotransformation of the chlorinated hydrocarbons more readily. Disappearance of 17 to 62 % and 22 to 99.9 % of the original concentration of PCE and CT were observed when the redox potentials of the microcosms were ranged from 225 to -263 mV and 188 to -263 mV, respectively. The viable count of microorganisms determined by the epifluorescence technique showed that higher concentration of primary substrate produced more biomass than lower concentration of primary substrate did, but the DNA content of the microbes was not a good biochemical indicator for the biotransformability of the chlorinated hydrocarbons. It is concluded that oxidation-reduction potential is the major factor controlling the biotransformation efficiencies of chlorinated hydrocarbons. In the case of in-situ biorestoration, proper control of redox potential of the environment will give a good result of remediation of the groundwater contaminated with chlorinated hydrocarbons.
Effluent Guidelines Compliance through Waste Minimization
Authors: Wood K. N. , Bishop A. L.
Published: May 2018

Ever-tightening regulations on releases to the environment have become a major business factor for the chemical industry. The Organic Chemicals, Plastics, and Synthetic Fibers (OCPSF) effluent guidelines have required many manufacturing sites to expand or upgrade their wastewater treatment plants (WWTP) at considerable cost. Du Pont has recognized the need to shift the emphasis from “end-of-pipe” treatment to waste reduction and elimination at the process source. The Du Pont Belle, West Virginia plant is implementing a program to comply with the OCPSF effluent guidelines by reducing the organic waste load to the WWTP, with secondary emphasis on upgrading the facility for more efficient treatment. This program will reduce the WWTP load by 50%, control priority pollutants at their source and minimize future shock loads from nine processes. This approach will save over $7 million of the investment that would have been required if the effluent reductions were achieved only from WWTP modifications. BOD loads have been reduced to date by over 40% and forecast permit exceedances have dropped from 19 to 2 since 1987. Other anticipated benefits of the waste minimization program are reduced sludge production and volatile organic emissions, as well as greatly improved product yield in one process.
Sorption of Reactive Dyes by Aeromonas biomass
Authors: Hu T. L.
Published: May 2018

Because of the cheaical stability of the dye compounds and the difficulties of treating dyeing wastewaters by conventional processes, the reaoval of colour from textile and/or dyeing wastewaters is one of the major environmental problems. Reactive dyes are the largest class of dyes, and also one of the commonly used dyes with great variety of colours.

Bacteria and yeasts with the ability of colour adsorption were isolated from activated sludge and soil samples. Eleven reactive dyes (100 mg/l) with different colour spectra were tested; the colour removal efficiencies ranged from 12.9-94.3 %, among these dyes, RG, a red colour dye, was effectively adsorbed by the isolated Aeromonas biomass. The specific adsorption capacity was 27.41 (mg dye/g dried cell), the ability to remove colour was 60.3%. The adsorption isotherm follows the Freundlich model, and the main adsorption site occurred at the cell wal1 portion.
Cod Removal in a Closed Water Circuit of a Papermill by an Anaerobic Fluidized Bed Reactor
Authors: Barascud M. C. , Ehlinger F. , Pichon M. , Rouger J.
Published: May 2018

In waste paper processing mills, entirely closed process water systems cause high specific polluting problems, deteriorate the quality of the paper produced and corrode the equipment.

Operating an anaerobic fluidized bed on part of the circulating water could make it possible to achieve lower dissolved organic concentration in the closed process water system.

Laboratory experiments have been carried out according to the following flow-sheet : Water circuit; Acidification tank; Fluidized bed.

When the anaerobic treatment is added to the water circuit, COD removal is 75% in the circuit and 65% in the acidification tank. Consequently, until reaching steady state, the organic load entering the fluidized bed decreases continuously from 28.75 to 9.86 kg COD/m3 d−l without disturbing biomass activity.

From a mass balance, a mathematical model is drawn to check the COD removal in the water circuit and study the transitory period.

Efficient fluidized bed performances are achieved even with high organic load (28.75 kgCOD/m3d−1) 52% to 75% COD removal are obtained in the water circuit respectively within 75 and 24 hours. The treated water represents a very small part of the circulating water. To achieve 52% COD removal the equivalent of 0.5 m3/t produced paper is treated. For a 75% COD removal efficiency, treated flow rate is 2.6 m3/t produced paper.
NMR Imaging of Hydrodynamics Near Microbially Colonized Surfaces
Authors: Lewandowski Z. , Altobelli S. A. , Majors P. D. , Fukushima E.
Published: May 2018

Nuclear magnetic resonance imaging (NMRI) was used to study fluid flow in a model flow bioreactor as a function of biofilm formation. NMRI in which the phase of the nuclear spins depends on the spin velocity was used to obtain fluid velocity distribution, whereas images predominately of the biofilm density were obtained by spin-lattice relaxation time weighted data. Velocity images showed the manner in which the fluid velocity changed around a biomass growth. We conclude that NMRI is an excellent tool to study these systems.
Measurement of the Activity of a Biofilm: Effects of Surface Loading and Detachment on a Three-Phase, Liquid-Fluidized-Bed Reactor
Authors: Rittmann B. E. , Trinet F. , Amar D. , Chang H. T.
Published: May 2018

A method to measure the fraction of biofilm bacteria active in respiration was developed and applied to a three-phase fluidized-bed biofilm reactor. The substrate flux (J) and the biofilm detachment coefficient (bs) were controlled independently. The experimental results showed that the amount of biofilm per unit of carrier surface area (XfLf) was controlled by J and bs. However, the biofilm's active fraction was proportional to J, but independent of bs for these experiments with relatively large bs values. When J was increased, the biofilm had less inactive biomass, because the substrate concentration was higher and allowed the cells to maintain a higher growth rate. Accompanying the increased activity were an increase in the observed biomass yield and a decrease in the oxygen consumption. These results provide a tool to control bioparticle fluidization, oxygen consumption, and sludge production.
Modelling of Toluene Biodegradation and Biofilm Growth in a Fixed Biofilm Reactor
Authors: Arcangeli J. P. , Arvin E.
Published: May 2018

The modelling of aerobic biodegradation of toluene and the associated biofilm growth in a fixed biofilm system is presented. The model includes four biomass fractions, three dissolved components, and seven processes. It is assumed that part of the active biomass is composed of filamentous bacteria which grow relatively fast and detach easily, leading to a biomass growth delayed with respect to substrate degradation. The non-filamentous bacteria inside the biofilm also degrade toluene but with a slower rate compared to the filamentous bacteria. Because the nonfilamentous bacteria do not detach, they are primarily responsible for the biofilm growth. The active biomass decays into biodegradable and “inert” dead biomass which is hydrolysed into soluble products at two different rates. These products are partly degradable by the biomass and constitute the endogenous respiration. The dynamic growth phase with toluene degradation was successfully modelled as well as the decay phase when toluene addition was turned off. In addition to this, modelling of toluene removal and oxygen consumption versus toluene concentration in the reactor was performed. This required consideration of inhibition of substrate degradation due to the combination of high oxygen and toluene concentrations.
Treatment of Dairy Wastewater in a Novel Moving Bed Biofilm Reactor
Authors: Rusten B. , Ødegaard H. , Lundar A.
Published: May 2018

A novel moving bed biofilm reactor has been developed, where the biofilm grows on small, free floating plastic elements with a large surface area and a density slightly less than 1.0 g/cm3. The specific biofilm surface area can be regulated as required, up to a maximum of approximately 400 m2/m3. The ability to remove organic matter from concentrated industrial effluents was tested in an aerobic pilot-plant with two moving bed biofilm reactors in series and a specific biofilm surface area of 276 m2/m3. Treating dairy wastewater, the pilot-plant showed 85% and 60% COD removal at volumetric organic loading rates of 500 g COD/m3h and 900 g COD/m3h respectively. Based on the test results, the moving bed biofilm reactors should be very suitable for treatment of food industry effluents.
Design and Operational Analyses of Activated Sludge Processes Using Respirometrically Calibrated Models
Authors: Rozich A. F.
Published: May 2018

The purpose of this paper is to present the background and examples of methodology which enable environmental engineers and scientists to analyze activated sludge processes much more effectively than is otherwise possible with conventional approaches. Good process analyses are key for devising optimal design and operational strategies. The key features to the technique presented herein are the field-proven predictability of the model and the methodology for collecting data needed for calibrating the process model. Case histories prove the predictability of the model that is associated with the process analysis approach. The advantage of the approach advocated herein is the use of respirometric techniques to calibrate the model. These methods enable the process analyst to collect the requisite data for model calibration in twenty-four hours or less. This feature enables one to use this process analysis methodology for both design and operational applications. The paper will present the technical basis for the process model and how respirometric methods are utilized to compute biokinetic constants in a manner which is consistent with kinetic theory. Case histories will be discussed that demonstrate the predictability of the modeling approach and demonstrate the utility of this tool for process analysis.
Effects of Heavy Metals on Activated Sludge Process
Authors: Dilek F. B. , Yetis Ü
Published: May 2018

The purpose of this study was to evaluate the toxic effects of various heavy metals on activated sludge process. Different concentrations of Cu(II) (0.5, 1.0, 5.0, and 10.0 mg/l), Ni(II) (5.0, 10.0, 25.0 mg/l), and Cr(VI) (1.0, 5.0, 10.0, 25.0, 50,0 mg/l) were maintained in a laboratory-seale completely mixed activated sludge unit, without recycle, treating simulated wastewater. The feed solution contained 650 mg/l protein (corresponding to 1300 mg/l COD) as a source of carbon. Experimental results indicated that the treatment efficiency was not adversely affected by the presence of these heavy metals up to 10.0 mg/l Cu(II), 10.0 mg/l Ni(II) and 50,0 mg/l Cr(II) concentrations. Moreover, some stimulatory effects of these heavy metals on the biokinetic parameters; maximum specific growth rate and half-substrate saturation coefficient were observed.
Denitrification of Nitrate-Rich Water Using Entrapped-Mixed-Microbial Cells Immobilization Technique
Authors: Nitisoravut S. , Yang P. Y.
Published: May 2018

A denitrification process was examined by using Entrapped-Mixed-Microbial Cells Immobilization (EMMCI) process. The mixed microbes were entrapped into a polymeric cellulose triacetate. The reactor was operated over one year with feed concentration ranging from 50 to 850 mg NO3-N/l. The hydraulic retention times (HRT) were also varied from 1.8 to 11.3 hours. Complete denitrification was obtained at an HRT of 2.6 to 11.3 hours. At an HRT of 1.8 hours, the maximum nitrate-N loading rate of 591.6 g/m3 ·h (based on carriers volume) was achieved with an 88.3% denitrification efficiency. Under high range of NaHCO3 concentrations from 10 to 20 g/l, the denitrification efficiency above 96% could be obtained. This EMMCI process has showed very promising results in respect to nitrate removal. It can be considered as an alternative approach tor direct treatment of nitrate-rich water or in a combination with an ion exchange process with an intent to eliminate the high nitrate concentration from the spent regenerant.
Design Procedure and Pilot Investigations for the Extension of the Main Treatment Plant of Vienna
Authors: Emde W. v. d. , Kroiss H. , Nagel G. , Domhofer K.
Published: May 2018

The Main Treatment Plant in Vienna Simmering has been in operation since 1980. It does not meet the future demands on removal efficiency and therefore it has to be expanded. On the basis of stringent emission values, of a detailed comparison of alternatives and of intensive pilot investigations a concept has been developed which makes optimal usage of the existing plant and of the limited availability of space on site. The concept that has been developed for the extension is a two stage plant with the existing plant as the first stage. The plant will be operated as a two stage plant under dry weather conditions and in a parallel mode under storm conditions in order to reduce the load on the final clarifiers. This kind of operation has been tested in a period of two years in pilot investigations in which all future modes of operation were investigated and the chosen concept proved to be successful.
Berliner-Becken: A New Developed Secondary Clarifier with a Vertical Flow
Authors: Peter A. , Schmidt V.
Published: May 2018

The two wastewater treatment plants of the western part of Berlin must be extended for which only little space is left. Therefore new space-saving secondary clarifiers, the Berliner-Becken, have been developed. The efficiency is comparable to the Dortmund tanks but they only take up about 55% of the space.
Real Time Control of Wastewater Treatment Operations
Authors: Novotny V. , Capodaglio A. , Jones H.
Published: May 2018

Real Time Control (RTC) of wastewater treatment processes is an alternative to the present static, or time-invariant, mode of control during which wastewater in excess of a predetermined capacity is bypassed or diverted into an overflow. RTC control relies on modeling to predict the near future (i.e. next operation interval) influent loads, parameters and performance of the system and effluent water quality characteristics. Based on these predictions the RTC system and/or the operator can adjust and optimize the performance of the system using the control options built into the system itself.

The paper describes the concepts of the RTC operational control of wastewater treatment facilities, modeling techology, strategy and applications.
Experience with Ceramic Plate Diffusers in Large Activated Sludge Plants
Authors: Warriner R. , Rooney T. C.
Published: May 2018

Fine pore aeration systems were evaluated in a U.S.EPA sponsored study of oxygen transfer efficiency in 26 activated sludge plants. Two plants in the study, those of the Milwaukee Metropolitan Sewerage District, had aeration systems composed of flat plates grouted into containers placed flush with the basin floor. The remaining plants in the study had aeration systems utilizing various disk, dome, and tube devices that are now in far more widespread use than the flat plates. The District's aeration basins gave better oxygen transfer efficiency than the other ceramic diffuser systems studied. The difference may have been the result of the high tank area to diffuser area ratio and the low air flux rates associated with the plate systems.

At one MMSD plant there were also four basins with recently installed ceramic disk diffuser systems. This provided an opportunity for side-by-side comparisons between the disks and the flat plates in containers. An analysis of diffuser system first costs and energy costs indicated that the ceramic plate system could be cost effective at higher power costs, but not at the prices presently paid by the District for power.
Baviaanspoort Wastewater Reclamation Plant
Authors: de Wet F. J. , Barnard J. L. , Saayman G.
Published: May 2018

The lack of sufficient new water resources has encouraged the indirect use of wastewater in the Pretoria-Witwatersrand-Vereeniging area of South Africa with an estimated population of 8 million and which is situated at a high altitude. Effluents must comply with nitrogen and phosphate standards, as well as COD and SS. The solution was to construct a BNR plant with a follow-up of flotation to treat not only the new extensions but also the older plants for SS removal as well as for standby chemical removal of phosphates. The plant has now been in operation for a year and the results are given in the text.
Operational Results of the Wolfsburg Wastewater Treatment Plant
Authors: Kayser R. , Stobbe G. , Werner M.
Published: May 2018

At Wolfsburg for a load of 100,000 p.e., the step-feed activated sludge process for nitrogen removal is successfully in operation. Due to the high denitrification potential (BOD:TKN = 5:1) the effluent total nitrogen content can be kept below 10 mg l−1 N; furthermore by some enhanced biological phosphate removal about 80% phosphorus may be removed without any chemicals.
Design, Operating Results and Experiences of Two Large-Scale Treatment Plants with Biological Nitrogen and Phosphate Elimination
Authors: Seyfried C. F. , Hartwig P.
Published: May 2018

This is a report on the design and operating results of two waste water treatment plants which make use of biological nitrogen and phosphate elimination. Both plants are characterized by load situations that are unfavourable for biological P elimination.

The influent of the HILDESHEIM WASTE WATER TREATMENT PLANT contains nitrates and little BOD5. Use of the ISAH process ensures the optimum exploitation of the easily degradable substrate for the redissolution of phosphates. Over 70 % phosphate elimination and effluent concentrations of 1.3 mg PO4-P/I have been achieved.

Due to severe seasonal fluctuations in loading the activated sludge plant of the HUSUM WASTE WATER TREATMENT PLANT has to be operated in the stabilization range (F/M ≤ 0.05 kg/(kg·d)) in order not to infringe the required effluent values of 3.9 mg NH4-N/l (2-h-average). The production of surplus sludge is at times too small to allow biological phosphate elimination to be effected in the main stream process. The CISAH (Combined ISAH) process is a combination of the fullstream with the side stream process. It is used in order to achieve the optimum exploitation of biological phosphate elimination by the precipitation of a stripped side stream with a high phosphate content when necessary.
Sludge Disposal Concept of Ruhrverband
Authors: Imhoff K. R.
Published: May 2018

Since 1913 the Ruhrverband has been responsible for comprehensive water quality and water quantity management in the Ruhr River basin, covering an area of 4,488 km2. In 116 municipal wastewater treatment plants sludges with 59,000 tons of dry solids are annually retained. For the year 2000 a total of 75,000 tons is expected. The paper describes the development of a basin-wide sludge disposal concept under realistic assumptions. As treatment plants of varying sizes are existent, all three applicable routes of sludge disposal must be kept open for the future: 1. agricultural utilization, 2. controlled disposal after dewatering and 3. incineration.
Upgrading of 100 000 PE Goch Sewage Treatment Plant – Design of 2-Stage Sewage Treatment and Anaerobic Thermophilic/Mesophilic Sludge-Stabilisation
Authors: Kugel G. , Zingler E. , Hellfeier G.
Published: May 2018

The 100 000 PE Goch STP is to be upgraded by implementing a 2-stage activated sludge process with integrated nitrification and denitrification to treat strong sewage water dominated by potato processing wastes. Thermophilic (75 °C) acidification reactors will be added to mesophilic (38 °C) digesters (total hydraulic retention time about 13 days).
Predicting the Fate of Volatile Organic Compounds in Municipal Wastewater Treatment Plants
Authors: Melcer H. , Bell J. , Thompson D.
Published: May 2018

Pilot plant and full scale investigations were carried out to determine the fate of selected volatile organic compounds (VOCs) in activated sludge aeration basins. Treatability parameters for each VOC were estimated from these investigations and used to calibrate TOXCHEM, computer-based steady state and dynamic models developed to predict the fate of VOCs in municipal activated sludge systems. The pilot plant was fed with wastewater from two different municipal sources. It was operated in parallel with a municipal treatment plant and was found to adequately simulate the performance of the full scale plant. Data suggest that the current models, calibrated with pilot plant data, may produce useful predictions of the fate of VOCs in full scale plants.
Investigation of Batchwise Nitrite Build-Up by an Enriched Nitrification Culture
Authors: Yang L. , Alleman J. E.
Published: May 2018

Nitrite build-up within biological wastewater treatment systems has generally been attributed to unsuitable environmental and process conditions. In this study, an enriched nitrifying culture was used to investigate the cause of nitrite build-up by controlling dissolved oxygen (DO) and total ammonia concentrations as well as pH level in a batch system. At pH 7.5, nitrite build-up was observed with a low DO level (0.5 mg/L), while no nitrite accumulation was found in the system with a high DO level (6.0 mg/L). However, nitrite peaks were found in both the high and low DO systems at pH values of 8.0 and 8.5. Conversely, at pH 7.0, no nitrite accumulated in either such system. Hence, DO level did not appear to be the dominant factor behind a nitrite build-up, and the correlation with free ammonia (FA) was erratic. On the other hand, hydroxylamine, an intermediate in nitritification by Nitrosomkonas, has been found to inhibit nitratification by Nitrobacter. Indeed, based strictly on the mechanistic pathways of nitritification, hydroxylamine appeared likely to accumulate in a nitrifying system subjected to deficient oxygen. The results of this research showed that variable levels of hydroxylamine would accumulate in a batch system under all conditions. Relative to nitrite build-up, the presence of unionized or so called free hydroxylamine (FH) fraction (as opposed to ‘total') appeared to have a consistent correlation with incomplete nitrification. In turns, FH was believed to be a major, if not principal, factor behind nitrite build-up in these batch nitrifying systems.
A Study of Nitrification Utilizing Whole Microorganisms Immobilized by the PVA-Freezing Method
Authors: Asano H. , Myoga H. , Asano M. , Toyao M.
Published: May 2018

The particular characteristics of nitrifying bacteria are that they have a reduced tendency to flocculate, a lower specific growth rate and a higher specific nitrification rate. Accordingly, we used whole microorganisms immobilized by the PVA-freezing method (in order to prevent microorganism wash-out) to investigate the characteristics and efficiency of their nitrification. The following results were obtained.By comparsion with suspended microorganisms, the nitrification rate of immobilized microorganisms was not as affected by temperature and their storage stability was better.The nitrification efficiency of a recycling operation in a biological nitrogen removal system was compared with that of a once-through operation, using immobilized microorganisms. The results showed that the ratio of allowable volumetric loading in the recycling operation was 60% of that in the once-through operation.
Denitrificiation in a Non-Nitrifying Activated Sludge System
Authors: Lyngå A. , Balmér P.
Published: May 2018

Post-nitrification and recycling of the nitrified effluent to an anoxic zone in an activated sludge system for denitrification is proposed as a potentially cost-effective method for nitrogen removal in existing activated sludge treatment plants. Denitrification in a non-nitrifying activated sludge system with a SRT of 3-4 days has been studied in pilot scale. The results show that denitrification rates of at least 10 g N03-N/(kgVSS h) can be achieved. At COD/NO3-N ratios above 15, nitrate supply appears to control the denitrification rate while at COD/NO3-N ratios below 15 the rate appears to be controlled by the supply of easily biodegradable organic matter.
Joint Consideration of Combined Sewerage and Wastewater Treatment Plants
Authors: Durchschlag A. , Härtel L. , Hartwig P. , Kaselow M. , Kollatsch D. , Otterpohl R. , Schwentner G.
Published: May 2018

Wastewater treatment plants, combined sewerage, catchment areas, storage tanks and overflows have to be regarded together. Stormwater runoff results in discharges at combined sewer overflows and higher pollutant loads in the effluent of the treatment plants. Characteristics of catchment areas and sewerage, number and capacity of storage tanks and overflows determine the characteristics of the combined water influent of the treatment plant. The plant has to cope with a higher hydraulic load and often with higher pollutant loads at the beginning of combined water flows. Some of the effects are displacement of sludge to the secondary clarifier, higher solids concentrations in the effluent and high loads of ammonia nitrogen for the nitrifying reactor. To decide on bigger stormwater storages or improvement of the treatment plant all effects in the whole system have to be considered. This can only be done with dynamic models, although simulation of combined water flows still have to be improved.
Evaluation of the California Wastewater Reclamation Criteria Using Enteric Virus Monitoring Data
Authors: Asano T. , Leong L. Y. C. , Rigby M. G. , Sakaji R. H.
Published: May 2018

The State of California's WastewaterReclamationCriteria is under review and will be revised and expanded to include several new regulations on the use of reclaimed municipal wastewater. To provide a scientific basis for the evaluation of the existing and proposed Criteria, enteric virus monitoring data from secondary and tertiary effluents were evaluated. These virus data were obtained from special studies and monitoring reports, covering the period from 1975 to 1989, including ten municipal wastewater treatment facilities in California. Based on the enteric virus data from these reports, and using the current Criteria as a guide, four exposure scenarios were developed to determine the risk of waterborne enteric virus infection to humans as a consequence of wastewater reclamation and reuse. The exposure assessments included food crop irrigation, landscape irrigation for golf courses, recreational impoundments, and ground water recharge.

The virus enumeration and the resulting risk assessments described in this paper provide a comparative basis for addressing the treatment and fate of enteric viruses in wastewater reclamation and reuse. The analyses show that annual risk of infection from exposure to chlorinated tertiary effluent containing 1 viral unit/100 L in recreational activities such as swimming or golfing is in the range of 10−2 to 10−7, while exposures resulting from food-crop irrigation or groundwater recharge with reclaimed municipal wastewater is in the range of 10−6 to 10−11. The risk analyses are also used to demonstrate that the probability of infection can be further mitigated by controlling exposure to reclaimed wastewater in the use area.
Public Evaluation of Municipal Water Reuse Alternatives
Authors: Bruvold W. H.
Published: May 2018

Models recommended for public involvement in environmental planning call for: 1) early and full involvement with technical planners from the start, 2) involvement at an intermediate phase once technical planners have developed a short list of the most feasible alternatives, and 3) later involvement only by ratification of the one alternative selected and developed by technical planners. The present study reports results assessing public involvement in planning at the intermediate phase using results from three general population surveys of the greater San Diego area done in 1989, 1990, and 1991 which dealt with municipal water reuse alternatives. Feasibility of the intermediate approach was demonstrated by correspondence between survey and technical planning evaluations and by consistency between and within survey findings.
Effects on Crops of Irrigation with Facultative Pond Effluent
Authors: do Monte H. M. , e Sousa M. S.
Published: May 2018

The experiments concerning the irrigation of three crops (a cereal, a forage crop and an oil–bearing crop) with the final effluent of a plant consisting of a facultative pond treating urban wastewater are described. Control plots were irrigated with potable water and given commercial fertilizers. The results of three years of experiments concerning the crop yields, crop quality both chemical and microbiological are presented.

The slightly better crop yield obtained in the plots effluent irrigated lead to the conclusion that the nitrogen content of the facultative pond effluent can replace the nitrogen from commercial fertilizers; subsequent fertilizer savings ranged from US$ 228/ha to US$ 533/ha. Crop composition shows very little or no change due to effluent irrigation. Crop contamination was virtually nil.
Performance Evaluation of Pilot Waste Stabilization Ponds in Subtropical Region
Authors: Khan M. A. , Ahmad S. I.
Published: May 2018

This research investigation was aimed at demonstrating the technical feasibility of facultative waste stabilization ponds under the climatic conditions of subtropical region. A pilot plant was designed and constructed at the Karachi University Campus for the treatment of domestic wastewater. An intensive analytical programme was followed for ten months for evaluating performance efficiency of the facultative ponding system.

The algal-bacterial symbiotic system performed satisfactorily and provided effluent with total BOD5 ranging between 26-76 mg/L, total COD ranging between 59-197 mg/L, TKN ranging between 5.35-47.82 mg/L, NH3-N ranging between 0.23-28.98 mg/L, and PO4-P between 1.41-6.76 mg/L. The maximum efficiency achieved for the removal of coliform, fecal coliform and fecal streptococci was 99.99%. The study demonstrated that high BOD5 loading of 507 kg/ha d was possible without deteriorating the quality of performance. It was particularly observed that wind velocity had a pronounced effect on the overall efficiency of the system. It was concluded that facultative ponding system is strongly feasible for this part of the world for the treatment of wastewater.
Factors in Environmental Improvement: Developing and Industrial Nations
Authors: Garber W. F.
Published: May 2018

When considering Worldwide environmental questions, it is convenient to compare the extremes of Developing Nations and Industrial Societies. Developing Nations are assumed to have a Gross National Product (GNP) of 4,000 dollars per capita per year or less with Industrial Nations having 10-12,000 dollars per capita per year or more. Using the history of the development of the U.S.A. as an Industrial Nation by reviewing its statistics over the period of about 1890 to the present, it can be seen that it mirrored the “environmental ” problems now observed in Developing Societies. It is accordingly suggested that it is not reasonable to expect environmental improvement as defined by the standards/criteria of the U.S.A. and other Industrial Nations to be possible for Developing Nations until their GNP reaches a similar level. Further, the Industrial Nations appear to be using a narrow definition of environmental improvement which wastes funds, harms their net environment and limits the possibility of aid for Developing Nations. It can also be argued that the World has become a single society in which Industrial and Developing areas cannot continue to separately exist, and that the net World environment will continue to degrade until Industrial Societies accurately define their environmental needs, maximize their use of funds and aid Developing Societies to increase GNP per person so that funds for World environmental improvement are available.