bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition of Anaerobic Digestion Caused by Heavy Metals
Authors: Mueller R. F. , Steiner A. 
Published: May 2018

The severity of heavy metal inhibition on anaerobic digestion is dependent on the metal species and their dissolved concentration in the digester. The general sequence of inhibition on anaerobic digestion of municipal sewage sludge was found with Ni &gt; Cu &gt; Cd &gt; Cr &gt; Pb. Metal immobilization affinity in the sludge followed the reverse sequence. Due to sulfide production during digestion high quantities of heavy metals are precipitating as highly insoluble sulfide salts.
Nickel was immobilized to 94 % in the digester and indicated the most dramatic effect on anaerobic digestion. At a concentration of 250 to 300 g Ni m-3 toxicity occurred. Lower nickel concentrations resulted in reversible process inhibition. Copper up to 1000 g Cu m-3 caused reversible inhibition of acid producing, fermentative, and methanogenic bacteria. The time necessary for recovery of the process was dependent on the initial copper concentration in the digester. The organisms indicated capability of adaptation to copper. The copper uptake in the digester was 97 %. Cadmium inhibited digestion of sewage sludge up to approximately 50 % at 650 g Cd m-3. For long durations of acclimation a tendency toward recovery was observed. The cadmium uptake in the digested sludge was 99 %. Chromium and lead were uptaken at 99.9 % during digestion. Hence, the addition of these metals up to 1000 mg Cr/l and 600 mg Pb/l showed only little effect on anaerobic digestion.
Extension of the Seehausen Sewage Works to Meet the New Requirements on Nitrogen and Phosphorus Removal
Authors: Ermel G. , Mennerich A. , Höper G. 
Published: May 2018

At the Seehausen Sewage Works, the sewage arising from the City of Bremen is treated. The maximum dry weather sewage flow is about 150,000 m3/d; under storm weather conditions the maximum flow is 300,000 m3/d. The existing plant consists of a primary sedimentation followed by a two stage activated sludge plant. Waste sludge is treated in 5 anaerobic digesters followed by dewatering centrifuges. At present, the plant achieves full removal of the BOD5, however no nitrification. In accordance with the new German water laws and with respect to the eutrophication problems encountered in the North Sea, both nitrogen and phosphorus removal are required in the future.
This paper describes the measures planned to enlarge the volume of the activated sludge plant for nitrification/denitrification and measures for biological phosphate removal by means of anaerobic basins. A new single stage activated sludge plant for 50% of the total sewage flow will be built. After completion of this plant, it will be operated in parallel with the existing two stage plant. Both, the old and the new part of the plant, will provide nitrification and denitrification. In addition, the new plant is designed for biological phosphorus removal. The existing secondary clarifiers will be connected to both plants at 50% each.
Biological Phosphorus Elimination Combined with Precipitation and Flocculation
Authors: Grünebaum T. , Dorgeloh E. 
Published: May 2018

As interactions between chemical precipitation and biological wastewater treatment are well known, biological phosphate removal should be considered for advanced nutrient removal. A combination of biological phosphate removal and chemical precipitation treatment is sensible and economic, when the precipitation step is used for removal of residual amounts of phosphate.
Improved biological phosphate removal and simultaneous precipitation both give increase in dry solids phosphate content. Assuming a concentration of 0.05 gP/gSS and an effluent suspended solids concentration of 20 mg/l the solids contribution accounts for a Ptot-discharge of 1 mgP/l wastewater. Efficient solid/liquid separation is therefore vital in achieving Ptot-limit values.
Elements in the Interpretation of Platinum Electrode Potentials in Biological Treatment
Authors: Heduit A. , Thevenot D. R. 
Published: May 2018

The zero current potential of a platinum electrode in a biological medium (wastewater, activated sludge) is strongly dependent on the surface characteristics of the metal. It is also influenced by pH (probably Pt/PtO system), dissolved oxygen (O2/OH- system), and ionic forms of nitrogen (NO2-/NH4+ and NO3-/NO2-systems).
The experimental values of the coefficients relating the stabilized potential of a platinum electrode to the logarithm of the concentration of the elements under consideration (Nernst equations) are significantly different from the thermodynamic coefficients corresponding to each reaction. The platinum is thus not in equilibrium with the dissolved redox reactants and is likely subject to mixed potentials in which the adsorbed components play an important role.
Instrumental Determination of Energy Oxygen and BOD5
Authors: Ciaccio L. L. 
Published: May 2018

An instrument has been developed that measures the amount of oxygen consumption of a wastewater sample in the presence of excess microbial population and dissolved oxygen. In a closed circulatory system the sample experiences rapid microbiological oxidation with a measurement of oxygen consumed (designated EO, energy oxygen) by a DO electrode.
The ABODA instrument (automatic BOD analyzer) measures EO of wastewater samples in less than one hour. EO shows an excellent correlation to BOD5 with correlation coefficients, r, of 0.997 and 0.99 for glucose-glutamate standard, and raw sewage and primary effluent samples, respectively. The reproduceability for the analyses are as follows: EO, 209 analyses with a weighted average cv of ± 5.1 % and BOD5, 200 analyses with a weighted average cv of ±9.8%. The instrumental determination of EO is not temperature dependent as the BOD5 test. Considering these factors the instrumental determination of EO allows the rapid measurement of BOD5.
Assessing the Risk of Noncompliance in Wastewater Treatment
Authors: Choudhury S. H. , Yu S. L. , Haimes Y. Y. 
Published: May 2018

This paper presents an integrated methodology that allows determining the probability of noncompliance for a given wastewater treatment plant. The methodology applies fault-tree analysis, which uses failure probabilities of individual components, to predict the overall system failure probability. The methodology can be divided into two parts : risk identification and risk quantification. In risk identification, the key components in the system are determined by analyzing the contribution of individual component failures toward system failure (i.e., noncompliance). In risk quantification, a fault-tree model is constructed for the particular system, component failure probabilities are estimated, and the fault-tree model is evaluated to determine the probability of occurrence of the top event (i.e., noncompliance). A list can be developed that ranks critical events on the basis of their contributions to the probability of noncompliance. Such a ranking should assist managers to determine which components require most attention for a better performance of the entire system.
A wastewater treatment plant for treating metal-bearing rinse water from an electroplating industry is used as an example to demonstrate the application of this methodology.
Biocarbone Aerated Filters - Ten Years After: Past, Present, and Plenty of Potential
Authors: Rogalla F. , Sibony J. 
Published: May 2018

About ten years ago, the first full scale Biocarbone aerated filter went into service in Soissons (France) for a capacity of 40 000 population equivalents. This compact wastewater treatment system combines aerobic biodegradation and filtration in one unit, eliminating the need for clarifiers and achieving high removal rates through fixed biomass. Since, a number of independent investigations have been performed to establish dimensioning criteria and process performance. This article summarises the reports of the US EPA, the Japanese JSWA, and the British WRC, as well as experiences acquired by cities and water authorities.
In pilot and demonstration scale, reactor kinetics, sludge production and energy consumption was measured. Most reports agree on removal rates up to 4 kg BOD/m3 d or nitrification rates around 0.6 kg N/m3 d. Sludge yields ranged consistently around 0.8 kg SS / kg BOD removed, but oxygen transfer measurements varied from 7 % to 15 %. Full scale experience confirms these values, and operation results from large plants in North America are given.
Several examples of using the Biocarbone process for low pollution residuals are demonstrated, including plants in Britain, Denmark and Switzerland. As tertiary installation fed with clarified secondary effluent, final residuals below 1 mg/l N-NH4 and 5 mg/l for SS and BOD can be achieved in a hydraulic detention time around one hour. On settled sewage, two hours detention time results in advanced secondary effluent quality below 5 mg/l N-NH4 and around 10 mg/l for BOD and SS. If an anoxic reactor is added, total nitrogen residuals below 10 mg/l can be achieved in about three and a half hours.
Pathogen Reduction Capabilities of Freeze/Thaw Sludge Conditioning
Authors: Sanin D. F. , Vesilind P. A. , Martel J. J. 
Published: May 2018

Freeze/thaw conditioning of sludges has been shown to be an effective and economical method of sludge dewatering especially for areas where natural freezing is possible. Freeze treatment dehydrates the sludge particles by freezing the water associated to the floc and upon thawing an easily drainable granular type of material is obtained. The solid content of the freeze/thawed sludge from specially designed freezing beds ranges from 30% to as high as 60%.
Pathogen reduction capacity of freeze/thaw conditioning has not been evaluated. The purpose of this study is to determine the variables affecting the pathogen reduction in freeze/thaw sludge conditioning. Previous research has shown that freezing rate, time in the frozen state, and temperature all influence the condition of the freeze/thawed sludge, and these are chosen to be the independent variables of the research. The three microorganisms- salmonella, fecal coliforms and plaque forming units for viruses-are chosen to be the dependent variables, since they best represent the other pathogenic microorganisms.
Three different rates, four different temperatures and three different times of freezing are tested for their effects on the reduction of the three selected microorganisms.
Results indicate that all of the parameters, time, rate and temperature of freezing have significant effects on the reduction of the indicator microorganisms.
Use of Biologically Active Barriers for in situ Treatment of Contaminated Groundwater
Authors: Kao C.-M. , Borden R. C. 
Published: May 2018

Aerobic biodegradation has been shown to be effective for many fuel spills. However, success is often limited by the inability to provide sufficient oxygen to the contaminated intervals due to the low solubility of oxygen. Nitrate can serve as an electron acceptor in place of oxygen and results in anaerobic biodegradation of organics via denitrification. Since nitrate is less expensive and more soluble than oxygen, it may be more economical to restore fuel-contaminated aquifers using nitrate rather than oxygen. The aim of this study is to design a two layer trench system to offer an alternative of treating groundwater contaminated with low levels of organics which will be less expensive than the biological and physical processes currently in use.
The proposed barrier includes a cement-nutrient(nitrate and phosphate)-briquet layer and a peat layer. Denitrifiers growing on the briquets in the first layer will use the nutrients released from cement-nutrient briquets and degrade BTEX transported into the surface of an attached biofilm. The peat layer will be used to adsorb the residual organics and remove excess nitrate.
Laboratory studies are being conducted to evaluate BTEX biotransformation and assess the potential to remediate contaminated aquifers using a nutrient briquet-peat barrier system. Batch equilibrium experiments were conducted to estimate the nutrient release rate and parameters for transport models. Simulated transport results were then compared with results from a one dimensional column test. Microcosm experiments were performed to evaluate BTEX degradation rate under aerobic, anaerobic, and denitrifying conditions. The microbial transformation of BTEX was also studied in a series of columns: a cement-nutrient briquet column, followed by a peat column and a soil column. This system was used to simulate biodegradation in a saturated-flow barrier. A feed solution containing anoxic synthetic groundwater amended with BTEX was pumped through the column. The column influent and effluent were monitored for dissolved oxygen, BTEX, nitrate, nitrite, ammonia, phosphate, pH, and other relevant parameters.
Strategies for Dealing with the Effects of Increasing Urbanisation on Surface Water Quality
Authors: Lötter L. H. 
Published: May 2018

Extensive research into sewage purification processes has enabled Johannesburg to produce environmentally high quality effluent from wastewater treatment plants, thus successfully controlling the largest point source contribution to surface water pollution in the Johannesburg metropolitan area. However, a variety of other point and diffuse sources require attention in order to protect the country's single most important resource.
Case studies involving pollution from sanitary sewers, zoological gardens, informal settlements and mine dumps are discussed. The effect of more stringent effluent control on the quality of rivers receiving sewage effluent is also discussed.
A Comparative Study of Full-Scale Sludge Dewatering Equipment
Authors: Andreasen Ina , Nielsen Bente 
Published: May 2018

A comparative study of 4 different types of full-scale sludge dewatering units was performed in 1990 by I. Krüger AS in co-operation with the equipment suppliers.
The purpose of the study was to examine the capability of the dewatering equipment on the “new” sludge types from wastewater treatment plants with N and P removal.
The achieved results have formed the basis of a financial evaluation comprising construction and operating costs. The objective of the evaluation is to compare the total costs involved in sludge dewatering and disposal.
The relatively cheap types of dewatering units (belt filter press, solid bowl centrifuge) produce dewatered sludge with a lower dry solids content than the more expensive equipment (press centrifuge, membrane filter press).
The latter types should consequently primarily be applied where the dewatered sludge has to meet special requirements and in situations in which disposal costs are very high.
Hybrid Upflow Anaerobic Sludge Blanket Reactor (HUASBR) Treatment of Dairy Effluents
Authors: Öztürk I. , Eroglu V. , Ubay G. , Demir I. 
Published: May 2018

This paper covers the treatability results of a laboratory-scale hybrid upflow anaerobic sludge blanket reactor (HUASBR) treating dairy effluents from a large integrated industry with a maximum production capacity of 500 tons of milk per day. The study began wilb the determination of effluent characteristics and pollution profile for the investigated dairy industry. As a result of observations, by-product recovery and waste reduction alternatives were investigated by in-plant control measures. Anaerobic treatability studies were conducted by a laboratory-scale hybrid upflow anaerobic reactor with an effective volume of 81.
The reactor was operated more that 270 days under mesophilic conditions and it was fed wilb the combined effluents from the investigated dairy industry. The hydraulic retention times ranged from 0.21 to 0.96 days under normal operating conditions after the start up. COD removal efficiencies of more than 87% were achieved at an organic loading rate (OLR) of 8.5 kg COD/m3·d OLR was gradually increased from 2.54 to 7.1 kg COD/m3·d within 15 days but the anaerobic reactor performances did not change significantly. The reactor was operated under varying feed characteristics to test the response of the system to high strength acid whey. The system can tolerate OLRs as high as 17 kg COD/m3·d with an average COD removal efficiency of 75% for two weeks. Although the reactor was fed by diluted effluent with an average COD of 1070 mg/l at very high hydraulic loadings (HRT=5 hours), 75% removals of COD were achieved under these conditions.
Principles of Operation and Experimental Results for a Small Wastewater Treatment Plant of 300 Population Equivalents
Authors: Bongards M. , Hengstermann T. , Köhne M. 
Published: May 2018

Small wastewater treatment plants play a very important role in German environmental politics. Presented here is a new system for biological wastewater treatment with simultaneous aerobic sludge stabilization. This system operates as a charge process and can be used in the range of 300 to 2000 population equivalents. Different modes of operation were tested in an experimental plant. The system is applicable for both separate sewerage systems and combined systems with large amounts of storm water. The quality of the purified water was good and even under the worst case conditions it met the demands of standard discharge consent conditions.
A theoretical simulation of the operation has not yet been started, because the system equations are very complex, due to the variable water volume.
Comprehensive Planning of Urban Drainage and Wastewater Treatment
Authors: Kollatsch Dirk-Th 
Published: May 2018

For upgrading the urban drainage system (UDS) the reduction of pollution impacts is the priority task concerning the environmental protection of the receiving waters. With simulation models the interactions between surface, sewer systems, overflow structures and treatment facilities within the UDS can be shown. Models to simulate the pollutant impacts, transport and the effects on the receiving waters are available.
In a first step a pollutant transport model of sewer systems and a model to simulate the wastewater treatment processes are connected. With these models the efficiency of upgrading measures can be checked in all parts of urban drainage systems.
The Health of Sydney Surfers: An Epidemiological Study
Authors: Harrington J. F. , Wilcox D. N. , Giles P. S. , Ashbolt N. J. , Evans J. C. , Kirton H. C. 
Published: May 2018

This study forms part of a three year prospective cohort research project which began with a pilot trial in the summer of 1989/1990. The study proper will span the summers of 1990/91, 1991/92 and 1992/93. In response to environmental concerns about sewage ocean outfalls, the Water Board commissioned this study of recreational use of six popular surfing beaches located north and south of Sydney Harbour.
A survey sample of 2003 recruits was enrolled on which 43,175 swimming events were recorded. Of these, 5879 (14%) had possibly attributable illness. A rise in relative risks was noted for total illness and respiratory illness but not for gastrointestinal illness. The relative risks for total illness in males rose from 1.79 in high frequency beach swimmers to 2.26 when high frequency beach swimming was combined with swimming at non-ocean sites. Females showed an increase in reported illness when beach swimming was combined with non-ocean swimming.
This study lends no support to the concept of correlating health risk in swimmers with threshold levels of currently used bacterial indicator organisms. The value of further exploring the role of Clostridium perfringens as an indicator organism is supported.
Advantages and Disadvantages of the Use of Immunodetection Techniques for the Enumeration of Microorganisms and Toxins in Water
Authors: Kfir R. , Genthe B. 
Published: May 2018

The application of immunological techniques to the analytical challenges presented by water pollution and its tremendous expansion during recent decades are reviewed. Examples of the immunodetection methods evaluated for their advantages and disadvantages in the water field include the use of enzyme-linked immunosorbent assays (ELISA) and radio-immuno-assays (RIA) for the direct detection of viruses from water concentrates; cyto-immuno-labelling and immunofluorescence techniques specific for rota and hepatitis A viruses; and the use of ELISA and immunofluorescence for the detection of bacteria (Legionella, faecal coliforms) and protozoan parasites (Giardia, Cryptosporidium). Jhe production and use of monoclonal antibodies against algal toxins are also evaluated.
The advantages to be gained by utilizing these techniques in the water field are numerous. In general, they simplify the detection method, shorten detection time and are less labour intensive than other conventional methods. They also provide a tool for the detection of pollutants that otherwise could not be identified. However, many disadvantages are associated with utilising immunological techniques. False positives are often reported due to reactions with nonspecific matter in the water sample or cross-reactivity with a wide range of organisms. These methods are also unable to indicate the viability of organisms. The successful use of immunodetection techniques in the water field often depends on their combination with conventional culturing methods and/or microscopic observation.
Toxin Release from Microcystis Aeruginosa after Chemical Treatment
Authors: Kenefick S. L. , Hrudey S. E. , Peterson H. G. , Prepas E. E. 
Published: May 2018

Cyanobacterial (blue-green algal) blooms in agricultural dugouts and eutrophic lakes or reservoirs are common across the Canadian prairies. These blooms have caused livestock and wildlife poisonings that have been attributed to neurotoxins and/or hepatotoxins produced by various species of cyanobacteria. The hepatotoxins are extremely potent acute poisons. For example, microcystin LR has an LD50 of 50 µg/kg, by intraperitoneal injection, in mice. Hepatotoxins may also pose chronic health risks. Consequently, their presence in drinking water sources is attracting increasing attention.
Chemical treatment with copper sulfate is the most common technique used to control algal blooms in drinking water reservoirs. Application of lime (calcium hydroxide) is an alternative treatment for the control of blooms. The effects of copper sulfate versus lime treatment on the release of microcystin LR from a naturally occurring bloom, involving three species of cyanobacteria including toxin-producing Microcystis aeruginosa, were studied.
Water samples collected after chemical treatment of algal bloom material were monitored for microcystin LR at specific time intervals. In three replicate trials, the cells treated with coppa- sulfate released the majority of the toxin present within cellular biomass during the first three days after treatment. Substantial toxin release was not observed when cells were untreated (control) or treated with lime. After release, the persistence of microcystin LR was monitored. The aqueous toxin concentrations declined according to first order kinetics with a decay constant of 0.25 d−1. The experimental conditions, involving high biomass content, may have favoured toxin degradation. The microcystin LR half life, under laboratory conditions, was 3 d from the time of maximum toxin release (2 to 4 d after chemical treatment), meaning that a 99% reduction would take approximately 3 weeks. These findings indicate that copper sulfate should not be used to treat potentially toxic cyanobacterial blooms in waters to be consumed by humans or animals within several weeks following treatment.