bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Predators on Nitrification in Aerobic Biofilm Processes
Authors: Lee Natuscka M. , Welander Thomas
Published: May 2018

The influence of predators on nitrification in aerobic biofilm processes was investigated in a laboratory study carried out using two aerobic continuous-flow suspended-carrier biofilm reactors operating in parallel on the same synthetic waste water. After nitrification was established in the reactors and stable operating conditions at 3 h hydraulic retention time were achieved, nystatin and cycloheximide, substances inhibitory to eucaryotic organisms, were added to one of the reactors to selectively inhibit the predators. The other reactor was operated as a reference, without inhibitors being added. Adding the inhibitors to the test reactor led to a rapid decrease in the quantity of biofilm-consuming predators, most of them rotifers and nematodes, and a simultaneous increase in nitrification, which finally stabilized at a level twice as high as in the reference reactor. The addition of inhibitors was then switched between the reactors, resulting in a rapid increase in nitrification in what had been the reference reactor, and a slow decrease in nitrification in the reactor in which the adding of inhibitors had been stopped. Again, approximately twice as high a nitrification rate was achieved with addition of inhibitors than without. The results clearly show that biofilm predators can have a strong negative effect on nitrification in aerobic biofilm processes.
Ecological Studies of Aerobic Submerged Biofilter on the Basis of Respiratory Quinone Profiles
Authors: Fujie Koichi , Hu Hong-Ying , Tanaka Hajime , Urano Kohei
Published: May 2018

Respiratory quinone profiles were applied as tools for identifying different bacterial populations in the aerobic submerged biofilter along with the change of environment such as the temperature and the loading of hard-biodegradable chemicals. To begin with, a novel and simplified analytical operation of respiratory quinones was developed. A diversity in microbial population was observed in the film cultivated at the higher temperature. The change of microbial population in the course of acclimation to hard-biodegradable chemicals such as dimethylformamide(DMF, hereafter) was clarified on the basis of quinone profile.
Dynamics of Nitrifying Biofilm Growth in Biological Nitrogen Removal Process
Authors: Liu Yu , Capdeville Bernard
Published: May 2018

A conventional laboratory scale annular reactor was employed to investigate the dynamics of nitrifying biofilm growth. A dense and thin nitrifying biofilm was developed in this study. The results showed that the active growth of the nitrifying biofilm can be characterized best by the increase of the specific substrate removal rate until a maximum value, at which the maximum active film thickness and active biomass were attained. It was found that non active biomass accumulation directly resulted in the reduction in the specific ammonium nitrogen removal rate, however the ammonium nitrogen surface removal rate was not affected by the additional biomass accumulation. As a result, the credibility of the classic method using the substrate surface removal rate to estimate the maximum active film thickness was doubted. It was expected that thinner nitrifying biofilm ranging from 20 to 30µm has a higher specific nitrification rate to be 9.0mgNH4+-N/mgCOD-biomass/day.
Microbiology of an Anoxic Trickling Filter
Authors: Rosén Maria , Welander Thomas
Published: May 2018

A pilot-scale study was performed to examine the microbiology of the anoxic trickling filter as used in post-denitrification
Full Scale Treatment of Phenolic Coke Coking Waste Water under Unsteady Conditions
Authors: Suschka Jan , Morel Jacek , Mierzwinski Stanislaw , Januszek Ryszard
Published: May 2018

Phenolic waste water from the largest coke coking plant in Poland is treated at a full technical scale. From the very beginning it became evident that very high qualitative variations in short and long periods are to be expected. For this purpose, the biological treatment plant based on activated sludge is protected through preliminary physical-chemical treatment and the results are secured by a final chemical stage of treatment. Nevertheless, improvements in the performance of the treatment plant have been found necessary to introduce. The experienced gained over the last five years has been described and developed improvements have been presented. At the preliminary stage the importance and necessity of preparation was evaluated. It was found essential to use dissolved air flotation, instead of a simple pressured air flotation system. Even with an average relatively high retention in the aeration tanks, there was an uneven distribution of load, dissolved oxygen concentration and oxygen uptake. Dissolved iron or highly dispersed hydroxide particulates in the over flow of the first chemical treatment stage has had a beneficial effect on activated sludge flocs. As a result not only the physical properties but also the overall effect of treatment.
Technological and Constructive Aspects of the Installation of Impermeabilizing Membranes
Authors: Teigeiro Fernando L.
Published: May 2018

Selection of the adequate lining systems for each specific application requires a knowledge of materials, installation techniques and availability of design alternatives.

Performance of materials and their interaction in composite multilayered applications and desiccation cracking of the clay layers underneath geomembranes are studied.

The design needs to meet all of the needs of the user/owner. The lining system must be practical, constructable and functional. The quality assurance function, therefore, should start at the design stage. The design should be reviewed for constructability by material supplier and/or installer as a checking function to ensure problems won't arise during construction. This participation contributes to the successful construction of the lining system and helps ensure that the intent of the design is met.
Increasing Regulations Result in Decreasing Operational Efficiency
Authors: Ganze Charles W. , Brown Richard L.
Published: May 2018

In 1972, the Congress of the United States of America passed major legislation called the Clean Water Act, which required all wastewater discharges to meet minimal standards. The Clean Water Act promoted efficiency and cost effectiveness.

The Gulf Coast Waste Disposal Authority was created in 1969 by the Legislature of the State of Texas to, among other things, own and operate wastewater disposal systems which would be protective of public health, “terrestrial and aquatic life, the operation of existing industries and the economic development of the state“.

Since enactment of the Clean Water Act, other pieces of legislation, rulings by courts of law, and rules established by the U.S. Environmental Protection Agency have thwarted many efforts to operate efficient and cost-effective wastewater treatment facilities. This paper will discuss several of the laws and rules that have discouraged efficiency and cost effectiveness.
U.S. EPA's Pollution Prevention RD&D Results: “Practical Tools for the Trade”
Authors: Bridges James S.
Published: May 2018

Waste minimization/pollution prevention has become the strategic approach to waste management in the 90s and the hope for environmental management as we enter the third millenium. Nearly a decade ago, EPA's Office of Research and Development began a focused Waste Minimization Research Program to identify and demonstrate technology for reducing the generation of wastes and shifted the Agency's priority from end-of-pipe controls to the prevention of waste generation. The purpose of this presentation is to share a number of the results from several years of researching engineering solutions to multi-media problems, building a sound scientific foundation to support pollution prevention (P2) principles, and developing and demonstrating pollution prevention technologies, tools, and techniques. The “tools of the trade” for pollution prevention are the research reports that provide results of technology development, the case studies and demonstrations of P2 technologies, and the technical guides and manuals for conducting P2 activities.

Technology Development - Tools resulting from technology development include the numerous research reports and briefs from: 1) the Life Cycle Assessment (LCA) Program, 2) Pollution Prevention Measurement Projects, and 3) the Innovative Clean Technologies Program.

Technology Demonstration - Tools resulting from technology demonstration include the research reports and summaries from: 1) the Waste Reduction Innovative Technology Evaluation (WRITE) Program, 2) the Waste Reduction Evaluation At Federal Sites (WREAFS) Program, 3) the New Jersey/EPA Waste Minimization Assessment Project, and 4) Small Generator Waste Minimization Assessment Program.

Technical Guides and Manuals - These tools include: 1) Facility Pollution Prevention Guide. 2) 16 industry specific guides to pollution prevention, 3) Background Document on Clean Products Research and Implementation, and 4) Industrial Pollution Prevention Opportunities for the 1990s.

Much of the EPA's Pollution Prevention RD&D Program has focused on the development and demonstration of practical tools to encourage the development and adoption of processing technologies mid products that will lead to reducing the aggregate generation rates for pollutants entering various environmental media. The strategic direction for pollution prevention RD&D through the 1990s is: 1) to study high risk environmental problems where P2 offers a cost-effective solution for reducing the risks, 2) to conduct cross-cutting research such as measurement, modelling, and LCA that can be applied to multiple problems, and 3) to establish joint global P2 RD&D ventures where products and processes know no waste generating boundaries.
Treatment of High-Strength, Complex and Toxic Chemical Wastewater: End-of Pipe “Best Available Technology” vs. an In-Plant Control Program
Authors: Belkin Shimshon , Brenner Asher , Lebel Alon , Abeliovich Aharon
Published: May 2018

A case study is presented, in which two approaches to the treatment of complex chemical wastewater are experimentally compared: an end-of-pipe “best available technology” option and an in-plant source segregation program. Both options proved to be feasible. Application of the powdered activated carbon treatment (PACT™) process for the combined end-of-pipe stream yielded up to 93% reduction of dissolved organic carbon, with complete toxicity elimination. In order to examine the potential for applying a conventional activated sludge process, a simplified laboratory screening procedure was devised, aimed at establishing baseline data of removability potential, defined either by biodegradation, activated carbon adsorption or volatilization. Using this procedure, the major source of the non-biodegradable fraction in the combined park's wastewater was traced to a single factory, from which twelve individual source streams were screened. The results allowed the division of the tested sources into three groups: degradable, volatile, and problematic. A modified wastewater segregation and treatment program was accordingly proposed, which should allow an efficient and environmentally acceptable solution. This program is presently at its final testing stages, at the conclusion of which a full comparison between the two approaches will be carried out.
Ecoclimatic influence on waste stabilization ponds (WSP) efficiencies. Case study of the sesimbra system
Authors: Mendes Benilde S. , do Nascimento M. Jenny , Pereira M. Irene , Bailey Gerard , Lapa Nuno , Morais Joa˜o , Oliveira J. Santos
Published: May 2018

Portugal has a great diversity of ecoclimatic areas and Sesimbra was chosen to carry out a study on WSP efficiencies over five years (1989 to 1993). According to Pina Manique & Albuquerque (1954), the climate is classified as Atlantic Mediterranean (AM). Some environmental and climatic parameters have been studied in order to define the area. The treatment system at Sesimbra has three ponds: anaerobic, facultative and maturation. The physical and chemical parameters studied in the WSP system were: Temperature, pH, Dissolved Oxygen, Conductivity, BOD5, COD, nitrates, nitrites, ammonia and total nitrogen, total and volatile suspended solids, total phosphorus and orthophosphates. Algal populations and the following microbiological parameters were studied: total and fecal coliforms, fecal Streptococci, Clostridium perfringens, Pseudomonas aeruginosa and some Enterobacteriaceae. The K and K20 kinetic parameters were studied and derived for the three ponds utilizing the seasonal regional characteristics from the surrounding area. These values were then correlated with temperature and the subsequent removal efficiencies for each pond deduced. The data obtained indicate a necessity to determine the seasonal fluctuations of the K and K20 kinetic parameters for the WSP systems.
Photolysis of aromatic chemical compounds in aqueous TiO2 suspensions
Authors: Nishida K. , Ohgaki S.
Published: May 2018

Photocatalytic degradation of the herbicide thiobencarb, monochlorobenzene and benzene was studied in aqueous TiO2 suspensions with a simulated sunlight, Pyrex-filtered xenon light (λ >290 nm). All these compounds were mineralized completely to carbon dioxide, and during the time-course of TOC, pH and anion were consistent. There were clear differences in the pH change and the time required for disappearance and mineralization between the three compounds.
Active oxygen species generated during chlorination and ozonation
Authors: Utsumi Hideo , Hakoda Masafumi , Shimbara Satoko , Nagaoka Hiroaki , Chung Youn-son , Hamada Akira
Published: May 2018

In water treatment, ultraviolet irradiation, ozonation, and chlorination are believed to produce various active oxygen species, which seem to participate in reactions with fumic acid, pollutants and bacteria. It was, however, very difficult to determine the actual kinds and amount of active oxygen during the processes because of deficiencies of method. In order to determine the kinds and amounts of active oxygen species which may participate in water treatment process, the spin-trapping ESR (electron spin resonance) technique was applied to measuring unstable free radicals generated during chlorination and ozonation. As spin-trapping reagent, DMPO (5,5-dimethyl-1-pyrroline-N-oxide) was dissolved in phosphate-buffered water, and the solution was treated by either chlorination or ozonation. Immediately after the treatment, ESR spectrum was measured at room temperature. Typical ESR spectra due to DMPO-OH were observed from both treatments, indicating the generation of hydroxy radical in chlorination and ozonation. In addition to DMPO-OH, several different signals were observed and their appearance depended on the chlorine or ozone concentration.
Technological Strategies for Protecting and Improving the Biological Treatment of Wastewater from a Petrochemical Complex
Authors: Rebhun Menahem , Galil Noah
Published: May 2018

The wastewater from a petrochemical complex is characterized by a diversity of pollutants including hydrocarbons, in free and emulsified form, phenols including cresols and xylenols, mercaptans, sulfides, ammonia and cyanides. The wastewater treatment of the reported petrochemical complex is based on a multiple stage treatment approach, consisting of physico - chemical, and biological processes. The biological treatment process could be efficiently protected by preliminary wastewater flow regulation, controlling hydraulic and pollutants loads. Additional protection and improvement of the biological treatment was achieved by preliminary removal of more than 90 percent of the oil found in free and in emulsified form in the raw wastewater. Significant reliability and efficiency could be achieved by a combined biological treatment consisting of aerated ponds, lime clarification and a water cooling industrial system, recycling treated effluent as make-up.
Pretreatment of Textile Industry Wastewaters with Ozone
Authors: Tzitzi M. , Vayenas D. V. , Lyberatos G.
Published: May 2018

Ozonation of textile industrial wastewaters was examined in CSTR and batch studies. Experiments were done for various types of textile wastewaters and for different reaction and retention times. Much better results were obtained using ozonation after the coagulation-precipitation stage. Also a mathematical model was developed, able to describe wastewater decolonization and COD reduction. In all cases the comparison between the model predictions and the experimental data was satisfactory.
Effects of clay on the fouling by organic substances in potable water treatment by ultrafiltration
Authors: Kim C. H. , Hosomi M. , Murakami A. , Okada M.
Published: May 2018

In water treatment by ultrafiltration, effects of clay on the fouling due to organic matter in cross-flow ultrafiltration were evaluated by fouling model materials and clay. Fouling model materials selected were BSA (Bovine serum albumin, MW68,000), Dextran (MW70,000), and humic acid (MW8,000-200,000) at a size larger than molecular weight cut-off (MWCO 50,000, polysulfone) and alpha-lactalbumin, Dextran (MW9,300), fulvic acid (MW8,000) for smaller size than and that kaolin was selected as a clay material. The flux of BSA, Dextran (MW70,000) increased with an increase in the amount of kaolin, and the flux of alphalactalbumin, Dextran (MW9,300), fulvic acid did not increase with kaolin. In contrast, the flux of humic acid decreased with an increase in the quantity of kaolin. It was found that in the direct ultrafiltration of river water clay materials did not affect the flux decline, and could contribute to the prevention of fouling due to organic matter. It seemed that the pore size of membrane plays an important role in the effect of clay on the fouling due to organic matter.
Discharge of Stable Organic Substances from the Chemical Industries
Authors: Undén Åke
Published: May 2018

In a programme started in 1988, the waste water discharges from the major chemical industries in Sweden have been investigated. The primary objectives were to gather information on the major sources of such discharges and to initiate action so as to achieve significant reductions where required. In this paper the investigation programme is presented together with some early conclusions. As could be expected there are no simple common rules for these industries, each effluent should be considered as a separate problem. It was concluded that these waste waters were in most cases more toxic than was acceptable, and that further purifying measures were required in these cases.
Characterization of a Biologically Treated Wastewater from Oil Reclaiming: Recording of Low Molecular Weight Organics and Estimation of Humic Substances
Authors: Gulyas H. , Reich M. , Sekoulov I.
Published: May 2018

Wastewater originating from oil reclaiming (COD about 300 mg/l, TOC about 70 mg/l) which was pretreated by equalization, neutralization, adsorption to activated sludge from a publicly owned treatment work, flocculation, and flotation and finally oxidized in an activated sludge process was analyzed for humic acids and gas chromatographically detectable organic compounds. The humic acid concentration was estimated to represent about 15% of the COD. Hydrocarbons were detected in activated sludge, but no hydrocarbons were identified gas chromatographically. In the two analyzed wastewater samples ethers (mainly containing polyethoxy structures), carboxylic acids and carboxylic acid esters were found. In one sample several nitrogen compounds (amines and amides) were detected. Except for l,l'-oxybis-(2-methoxy)-ethane, which was a constituent of both samples, the organic gas chromatographically detectable compounds differed completely from sample to sample. This is obviously due to changing composition of the processed spent oils.
Cattle keeping, fertilization and water quality - a pilot study
Authors: Maret Pascal
Published: May 2018

Significant damage to surface water is caused by cattle husbandry. Only one global approach of water management and farming techniques (breeding management and cultivation methods) will ensure significant results. A pilot study run in the west of France proved that water quality can easily be improved by renovating the cattle buildings. It also showed that manure used as a fertilizer covers cultivation needs, which allows substantial savings for the farmers.
Ozonolysis of 2,4-Dichlorophenol in a Two-Phase Solvent/Water System
Authors: Chang Chia-Yuan , Chen Jong-Nan
Published: May 2018

The ozonolysis of 2,4-dichlorophenol was investigated in a two-phase system. A new contact flow system was proposed in this study. The experimental results show that the mechanisms of organic removal can be divided into two stages. The first stage is a solvent extraction and the second stage is ozonolysis. The disappearance of organic is very quick in the first stage and slows down in the second stage. The kinetic of ozonolysis in this system approximately obeys second order behavior.
The development of a new water quality classification system for Finland
Authors: Heinonen P. , Herve S.
Published: May 2018

The water quality classification system in Finland consists of three different sub-systems: a quality-based classification of watercourses for recreational purposes, a raw water (for domestic use) classification and a quality classification of watercourses for fishing. As a combination of these three sub-systems a general water quality classification has been widely used since 1988. However, there is a need to improve this system to be more sensitive in classification e.g. in the occurrence of harmful substances, especially organic chlorocompounds originating from pulp bleaching, and the early stages of eutrophication in very oligotrophic lakes. Also the quality classification of small rivers, very typical for Finland, needs more data about the biocoenosis, the living part of the river. Some ideas to improve the classification system in these respects are presented.
Basic approaches in design of water quality monitoring networks
Authors: Harmancioglu N. B. , Alpaslan N.
Published: May 2018

The general trend in water quality management has been to gather and use information on water quality variables for purposes of planning, design, and operation of water resources systems and wastewater treatment. However, the growing concern for environmental quality has given rise to a new trend in respect of the impact of water quality variables on human health and life conditions. Thus, there is the need for better understanding of how water quality processes evolve both in time and space under natural and man-made conditions. This accentuates the need for more efficient practices of monitoring to satisfy the objectives of water quality management plans. Upon this need, the adequacy of collected water quality data and the performance of existing monitoring networks have been seriously evaluated within the last decade. Problems observed in available data and shortcomings of current networks have led researchers to focus more critically on design procedures used. This paper examines the state-of-the-art in design of water quality monitoring networks. Available design procedures are discussed with respect to three basic features of a network: selection of sampling sites, sampling frequencies, and variables to be sampled. In conclusion, recommendations are presented for improvement of current approaches to the design problem.
Evaluation of a biomonitor based on the phototactic behaviour of Daphnia magna using infrared detection and digital image processing
Authors: van Hoof François , Sluyts Hilde , Paulussen Jozef , Berckmans Daniël , Bloemen Heidi
Published: May 2018

A biological early warning system based on the phototactic behaviour of Daphnia magna has been evaluated in relation to the reproducibility of its response and sensitivity towards potential pollutants. In addition to the infrared detection system of the monitor, video recording and digital image processing have been used in order to obtain more information on the behaviour of the Daphnia. The biomonitor performed better with Daphnia clones selected on positive phototactic behaviour than with non selected organisms. The variations in response over a five day period were too large to allow a reliable use of the monitor. The biomonitor was not able to detect sublethal changes in behaviour.

Digital image processing of video recordings yielded more information on the behaviour of the Daphnia that the infrared detection system. Using this technique it was possible to detect sublethal changes in Daphnia behaviour as well as conceptual shortcomings in the existing behaviour.
Effect of species composition on stability and reproductivity of a small-scale microcosm system
Authors: Tanaka N. , Inamori Y. , Murakami K. , Akamatsu T. , Kurihara Y.
Published: May 2018

In this study, the effect of species composition on the stability and reproductivity of small-scale microcosm system was investigated. Small-scale microcosm system in this study was gnotobiotic type, which consisted of micro animals as predator, algae as producer and bacteria as decomposer. Three species of protozoa and three species of metazoa as predator, seven species of algae as producer and four species of bacteria as decomposer were employed. With these microorganisms, twenty-four sorts of species composition were made to investigate their effect on stability and reproductivity of microcosm system. As a result, some systems showed very high stability and reproductivity while some did not. And it was suggested that this high stable and reproductive microcosm system can be used as one of tools to assess the effect of genetically engineered microorganisms, micro pollutant and so forth on ecosystem level, because has enough capability to be applied as standard.
Distribution of heavy metals in seawater, sediment and biota of Jinhae Bay, Korea
Authors: Chan-Won Lee , Young-Tack Kwon
Published: May 2018

Over the past two decades, the coastal waters of Jinhae Bay have been extensively used by coastal communities and industries for the disposal of domestic and various industrial wastes, therefore increasing the level of pollutants in coastal waters with a subsequent increase in sediments, especially of heavy metals.

Specific objectives of this research are to investigate the distribution of heavy metal concentration in biota, to compare the concentrations with those in sediment and water and to relate the bioconcentration to the different heavy metals in biota obtained from several sites.

Sixty one percent of heavy metals was found in particulate form during the high runoff season and 32% during the dry season. The behavior of the particulate metals after flowing in to the enclosed coastal sea is an important factor in heavy metal contamination.

Copper, lead and chromium contamination of sediment was revealed at several sites. The bioconcentration factors (BCFs) of zinc, cadmium, copper, nickel, chromium and lead by the mussel (Mytilus edulis) were determined as 2,900, 2,814, 807, 423, 228 and 127 in the decreasing order, respectively.

The areas located nearest to highly populated city and industries exhibited mussels with the largest accumulation of copper, lead and chromium.
Methyl mercury in the dutch rhine delta
Authors: Pieters Hendrik , Geuke Victor
Published: May 2018

Samples of yellow eel from various locations in the Dutch Rhine area have been analyzed for trend monitoring of mercury since 1977. In the western Rhine delta mercury levels in eels have hardly changed since the seventies, whereas in the eastern part of the Dutch Rhine area a considerable decrease of mercury concentrations in eel has occurred. Because of continuous sedimentation of contaminated suspended matter transported from upstream regions, accumulation rates and concentrations of mercury in eel in the western Rhine delta remained at a relatively high level.

Analyses of methyl mercury in biota have been performed to elucidate the role of methyl mercury in the mercury contamination of the Dutch Rhine ecosystem. Low percentages of methyl mercury were observed in zooplankton (3 to 35%). In benthic organisms (mussels) percentages of methyl mercury ranged from 30 to 57%, while in fish species and liver of aquatic top predator birds almost all the mercury was present in the form of methyl mercury (> 80%).

During the period 1970-1990 mercury concentrations of suspended matter in the eastern Rhine delta have drastically decreased. These concentrations seemed to be highly correlated with mercury concentrations of eel (R = 0.84). The consequences of this relation are discussed.
Evaluation of biodegradation kinetics of organic wastewater in a laboratory river model
Authors: Zagorc-Koncan J. , Dular M.
Published: May 2018

A laboratory river model for the study of biodegradation kinetics of organic pollution in surface waters is presented. It enables an engineering - technological prediction of the impact of wastewater biodegradation on DO and TOC profile in a river downstream from the point of entry of wastewater effluent thus providing rapidly and inexpensively significant design information to an environmental scientist or engineer. The method was applied to the determination of degradation of pharmaceutical wastewaters. Biodegradation during adaptation and a comparative study on organic constituents, biodegradation rates in polluted and unpolluted river waters were simulated.
Causes and effects of “nitrate saturation” in phosphate-deficient water bodies
Authors: Uhlmann Dietrich , Paul Lothar
Published: May 2018

In many European water bodies with a high dilution rate (flowing waters, reservoirs, mountain lakes), the supply of nitrate from fertilized agricultural areas is so high that it may exceed the demand of the photoautotrophic organisms and also of the bacteria on the sediment/water interface by more than one order of magnitude. In oligotrophic drinking water reservoirs in Saxony, the atomic N/P ratio may exceed a magnitude of 5000:1. This nitrate excess is an indication of a lack of electron donors. Our data confirm the thesis that a feedback exists in these cases between phosphate deficiency and nitrate excess, i.e. nitrate may operate as a factor of oligotrophication. It is, however, unavoidable to control nitrate if the critical threshold for drinking water supply (CTDW) might be exceeded. This control has to be focused upon agricultural practices. In waste treatment plants, a final nitrification stage (instead of nitrification/denitrification) may be sufficient in situations where the mass flow of nitrate is governed by the non-point sources and where the CTDW is still not exceeded. On the other hand, control of phosphate is imperative in all cases where control of eutrophication is the primary management goal.
Performance of fixed film media integrated in activated sludge reactors to enhance nitrogen removal
Authors: Sen Dipankar , Mitta Pramod , Randall Clifford W.
Published: May 2018

Nitrification and denitrification were evaluated in multiple CSTR continuous flow fixed film systems at 12°C. Three systems were operated with three types of media installations and a fourth as a control without media. The media configurations evaluated included: (i) frame mounted fine pore sponge media supported on wires; (ii) free floating fine pore sponge media; and (iii) fixed location frame mounted rope media (ringlace). The pore size for sponge media was 14 pores per centimeter. Each system included a two-cell anaerobic zone with 17 percent of total volume, two-cell anoxic zone with 17 percent of total volume, and a three-cell aerobic zone with 64 percent of total volume. The multi-cell configuration was used to maximize kinetics of removal with suspended growth biomass and evaluate improvements in nitrogen removal beyond the levels achieved with suspended growth.

At the optimum location (aerobic cells 1 and 2), the nitrification in cells containing free-floating sponges was 143 percent of the control at aerobic MCRTs of 3.1 and 3.4 days, with 35 percent media volume to cell volume. The nitrification with rope media was 136 percent of the control in middle third of the aerobic zone. Removals with ringlace were poorer in the first aerobic cell operating at higher COD levels, and in the third aerobic cell which did not contain sufficient biofilm growth at low levels of COD. Nitrification was 14 percent higher in Systems 1 and 2 with fixed and free floating sponges, respectively, and 8 percent higher in System 3 (ringlace) when all systems were spiked with 20 mg/L additional ammonium over a 24 hour period. Optimizing location of the media, with higher density of media at locations where adequate COD and ammonium-N are available for biofilm growth increase nitrification on media. Studies in full scale systems show that COD and ammonium-N concentrations at downstream locations in the activated sludge basin increase during peak flows and with step feed of wastewater. This helps increase biofilm growth and improve nitrification on the media downstream locations.

Denitrification observed in the aerobic cells of the fixed film systems was in excess of the control. All aerobic cells were operated at D.O. levels in excess of 6.0 mg/L. The fraction of total denitrification under aerobic conditions was 0.0 in the control as compared to 0.14 to 0.24 with ringlace media and fixed sponge media, respectively, at an aerobic MCRT 3.1 days. Fraction aerobic denitrification in all systems increased with an increase in MCRT of suspended growth - to 0.21 in the control and 0.35 and 0.39 with ringlace and sponges, respectively, at aerobic MCRTs of 3.4 to 7.7 days.
Characteristics of an air-fluidized-bed biofilm reactor system with a multi-media filter
Authors: Tsubone Toshiaki , Kanamori Seiichi , Takechi Tatsuo , Takahashi Masahiro
Published: May 2018

A pilot scale study was conducted using an Air-Fluidized-Bed Biofilm Reactor (AFBBR) system with a Multi Media Filter (MMF). Soluble BOD (S-BOD) concentration in the effluent of the AFBBR had a correlation with total BOD (T-BOD) and Suspended Solids (SS) concentration in the effluent of the MMF. The lower the S-BOD in the effluent of the AFBBR was, the lower was not only T-BOD but also SS in the effluent of the MMF. It was found that as treatment proceeded, S-BOD was removed and the particle size of SS increased in the AFBBR. These results suggested that the mechanism of BOD removal in this system was: S-BOD was removed and a part of the S-BOD was changed to SS and the particle size of the SS increased in the AFBBR, and then the SS was removed by the MMF. Thus not only the T-BOD but also the SS in the effluent of MMF was lower when the S-BOD in the effluent of the AFBBR was lower. When the S-BOD in the effluent of the AFBBR was 8mg/L, T-BOD and the SS in the effluent of the MMF were 10mg/L and 4mg/L, respectively. In order to have an average S-BOD value in the effluent of the AFBBR of about 8mg/L, the T-BOD loading and the S-BOD loading needed to be less than 1.3kg/m3/day and 0.45 kg/m3/day, respectively. Even when the BOD loading was high, nitrification still occurred in this system.
Submerged upflow biotower operation and computer simulation
Authors: Neufeld Ronald D. , Badali Christopher A. , Powers Dennis , Carson Christopher
Published: May 2018

A two step operation is proposed for the biodegradation of low concentrations (< 10 mg/L) of BETX substances in an up flow submerged biotower configuration. Step 1 involves growth of a lush biofilm using benzoic acid in a batch mode. Step 2 involves a longer term biological transformation of BETX. Kinetics of biotransformations are modeled using first order assumptions, with rate constants being a function of benzoic acid dosages used in Step 1. A calibrated computer model is developed and presented to predict the degree of transformation and biomass level throughout the tower under a variety of inlet and design operational conditions.
Influences of wastewater composition and operating conditions on activated sludge bulking and scum formation
Authors: Kappeler Jürg , Gujer Willi
Published: May 2018

Bulking and scum formation (scumming) are common phenomena in activated sludge plants. Four main problem groups with filamentous microorganisms with different growth requirements are distinguished: (1) “Aerobic Bulking”, (2) “Scumming due to Actinomycetes”, (3) “Low F/M Bulking and Scumming” and (4) “Bulking due to Sulphide Oxidising Bacteria”. Various wastewater fractions, such as readily biodegradable substrate, surfactants, hydrophilic and lipophilic slowly-biodegradable substrate, inoculated filamentous microorganisms and sulphide, strongly influence the biocenosis composition. Apart from wastewater composition, operating conditions, such as solids retention time, reactor configuration, mechanical stress by recirculation pumps and insufficient oxygen supply, are often decisive for the occurrence of a bulking or scumming problem, as well. A predictive scheme for the possible occurrence of the four main problem groups is presented for different combinations of wastewater compositions, operating conditions and reactor design. All four problem groups can occur in aerobic nitrifying systems. In non-nitrifying systems, only “Aerobic Bulking” and “Bulking due to Sulphide Oxidising Bacteria” are expected, depending on wastewater composition and operating conditions. In systems with a large anoxic mass fraction, “Low F/M Bulking and Scumming” is typically the only problem group. Since wastewater fractions can hardly be manipulated in practice, at least operating conditions and reactor design should be optimised in order to obtain a better performance of the plants.
Quantification of the kinetic differences between communities isolated from completely mixed activated sludge systems operated with or without a selector using a novel respirometric method
Authors: Smets Barth F. , Ellis Timothy G. , Brau Stephanie , Sanders Richard W. , Grady C. P. Leslie
Published: May 2018

This study quantified the kinetic differences in microbial communities isolated from completely mixed activated sludge (CMAS) systems that were operated either with or without an aerobic selector preceding the main reactor. A new respirometric method was employed that allowed the determination of biodegradation kinetics from single oxygen consumption curves, thereby minimizing physiological changes to the examined communities during the assay. Results indicated that increased values for Ks and μmax for acetate, phenol, and 4-chlorophenol degradation were measured in the CMAS system operated with a selector. The biomass yields on acetate, phenol, and 4-chlorophenol were very similar in both systems. These findings indicate that the operation of CMAS systems with aerobic selectors may result in the selection for degrading populations with higher Ks and μmax values for both biogenic and xenobiotic organic compounds, and that substrate storage in the selector only partially contributes to increased substrate removal rates.
Advanced wastewater treatment plants in lagoons combined with biological contactors
Authors: Schleypen P.
Published: May 2018

Full-scale investigations have demonstrated that wastewater lagoons combined with rotating biological contactors can be installed for denitrification without much effort when designed for nitrification. By recirculation of a mixture of nitrified wastewater and biological sludge from the outlet of the high loaded sedimentation tank back to the inlet of the sedimentation pond the removal efficiency was consistently high combined with a high process stability. In addition a considerable amount of enhanced biological phosphorus removal could be attained simultaneously.
Upgrading of a wastewater treatment plant utilizing existing trickling filters and a new filter stage
Authors: Fruhen M. , Kühn W. , Dohmann M.
Published: May 2018

The upgrading of wastewater treatment plants with the objective of enhancing the elimination of nitrogen and phosphorus is a demanding undertaking as regards the choice of process technology, especially if the basic function of existing treatment systems is to be retained. With reference to an existing two-stage biological sewage plant with trickling filters in the second stage, the present paper illustrates how the volume of the activated sludge stage that is being enlarged can be minimized by exploiting the benefits of a primary treatment stage with high BOD5 elimination and by integrating the trickling filters in the main stream of the treatment chain. This requires that the extremely costly filtration stage that is essential for eliminating the phosphorus also fulfils other tasks, in this case residual denitrification.
Dynamic modelling of the population distribution in the anaerobic granular biofilm
Authors: Arcand Yves , Chavarie Claude , Guiot Serge R.
Published: May 2018

Significant downward gradient of glucotrophic (acidogenic) activity was experimentally observed as anaerobic granules were stripped off their surface bacteria. This indicated a clear predominance of fermentative bacteria in the external layer of the granules. This is consistent with the multilayer microstructural model evidenced by scanning electron microscopy (SEM) of cleaved granules. In contrast, acetoclastic activities were evenly distributed along the granule depth even though SEM had shown the core of granules of various sources to be almost exclusively composed of Methanosaeta-like bacteria. A detailed distributed diffusion-reaction mathematical model was developed to predict local substance and biomass concentrations at any depth within the granular biofilm. This intragranular model combines the kinetics of ten substances and eight trophic groups of microorganisms as well as physico-chemical constraints such as ionic dissociation and gas-liquid equilibrium, internal and bulk-surface interfacial diffusion mechanisms. Predicted results of this intragranular kinetic model have shown a drastic downward glucose gradient towards the centre, as a concentration of 10 μM in the bulk liquid boundary layer dropped to almost 0 at a distance less than 100 μm below the surface. In contrast, the model predicted very low to no gradients of acetate. However, the model predicted pH values 1 mm inside the granule to be over one pH unit more alkaline than in the bulk liquid. Hence this significant pH gradient could be the major factor which gives a competitive advantage for Methanosaeta-like population to proliferate in the granule core.
Centralized biogas plants combine agricultural and environmental benefits with energy production
Authors: Tafdrup Sòren
Published: May 2018

The concept of centralized biogas plants has been developed in Denmark. At present, 10 plants are in operation with capacities ranging from 50 to 500 tonnes of biomass per day. The biomass consists of approximately 80% manure co-digested with 20% organic waste from abattoirs and various food industries. The effluent is returned as nutritionally defined fertilizer, partly to the farms that supply fresh manure, and partly to other crop farmers. The plants are sited to ensure that the energy can be utilized, mainly for CHP generation. The heat is used for district heating of urban communities. Operational experience shows considerable increases in gas production primarily due to co-digestion of the manure with organic wastes. Possibilities of process regulation have been revealed, and stable thermophilic digestion has been achieved. A two-step process has turned out to be advantageous, the second step being lower temperature post digestion. Environmental and agricultural benefits include savings for farmers, improved fertilization efficiency, less greenhouse gas emission, and cheap, environmentally sound waste recycling. The working economy of the centralized biogas plants has improved, but there is still a need for further reductions in running costs if financially competitive plants are to be created without public investment grants.
Use of multi-stage continuous culture systems to investigate the effects of temperature on the methanogenic fermentation of cellulose-degradation intermediates
Authors: Watson-Craik I. A. , James A. G. , Senior E.
Published: May 2018

A three-stage continuous culture system was used to segregate the component physiological groups of an anaerobic cellobiose-degrading association enriched and isolated from a landfill site. The optimum temperatures for methanogenesis were 30-35°C, although differences apparent in Vessels B and C at lower temperatures suggested the presence of distinct populations in the two vessels. There was no evidence of thermophilic methanogenic activity. Sulphate-reducing bacterial (SRB) activity was less affected by temperature perturbation, and there was significant SRB activity at 55°C.
Experience on anaerobic treatment of distillery effluent with the UASB process
Authors: Driessen W. J. B. M. , Tielbaard M. H. , Vereijken T. L. F. M.
Published: May 2018

Since the development of the UASB process in the 1970s this process has been widely applied for the treatment of industrial effluents. Effluents from alcohol producing industries are mostly highly polluted and therefore in principle very suitable for anaerobic treatment.

Distilleries use different kinds of raw materials such as sugar cane juice, sugar cane molasses, sugar beet molasses, wine or corn for the production of alcohol. The use of different materials and the different processes applied, result in a wide variety of effluents produced. The process conditions under which good results of the anaerobic process are obtained depend heavily on the type of distillery effluent being treated. The choice of the right set of process parameters for every type of distillery effluent has shown to be of crucial importance for the anaerobic process.

Experience of anaerobic treatment on effluents from different alcohol-producing industries over a long term period are discussed. Special attention is given to the treatment of effluents from sugar cane based distilleries with very high COD concentration of 60 000 to 160 000 mg COD 1−1. Despite expected toxicity problems arising from the high concentrations of COD, sulfide and salts, anaerobic treatment with the UASB process proved to be successful in treating distillery effluent.
Improvement of sludge sedimentation by installation of upward flow clarifiers
Authors: Thorndahl Uffe
Published: May 2018

The secondary clarifier is a very important part of the biological treatment. The better the secondary settlement works, the higher sludge concentration can be achieved in the process tanks, and the higher the sludge concentration, the better purification, or perhaps the less process volume is needed. But in many cases keeping the emission standards with regard to suspended substance creates problems to the sewage works. The traditional solution is installation of a new sedimentation tank or perhaps a sand filter, and these solutions are generally expensive. Another usual problem often comes up during rain at a sewage works which apart from wastewater also receives the load of rainwater. Such a hydraulic overload means a substantial risk of washing out of the active biological sludge through the secondary clarifier and into the recipient where the washed out sludge may create a substantial pollution problem. Furthermore, washing out of the biological sludge will delay the biological treatment as it takes some time before the biological treatment becomes effective again. These problems can, however, be solved by installing an upward flow clarifier which secures a considerable reduction of the emission of suspended substance and will, to a certain extent, stop the washing out of biological sludge during rain.