bluuebunny/crossref_metadata_2025 huggingface dataset:
Small Activated Sludge Performance and Viability Characteristics under Intermittent and Reduced Flows
Authors: Beler Baykal Bilsen
Published: May 2018

Small activated sludge systems operate in transient states under intermittent and variable flows. Simulations for such a treatment plant in a summer house site operating on a seasonal basis is investigated for system performance and viability using the five component inert soluble substrate generation model. The results have revealed that the viability drops to zero within the first month after the cessation of the feed for intermittently loaded systems that are fed during the summer months, while it never reaches that value for systems operating all year round with reduced flows off season. Restartup is compulsory for the intermittent loadings while the system adapts itself in a stepwise manner for the year round operation. Other factors being comparable, conventional operation with shorter sludge ages may be preferable since viability of the sludge is higher and the effluent COD is comparable.
Advances in the Design of Fine Bubble Aeration Plants
Authors: Brade C. E. , Shahid K.
Published: May 2018

Problems associated with the design and operation of smaller activated sludge plants are discussed with respect to reactor geometry. Advances in fine bubble diffuser design and some new concepts in the process design of smaller activated sludge type plants are described. It is concluded that plant design and operation can be improved by carefully selecting reactor geometry and aeration equipment.
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.
Coagulation in Drinking Water Treatment: Particles, Organics and Coagulants
Authors: Edzwald J. K.
Published: May 2018

A review of coagulation in drinking water treatment is presented. The paper emphasizes the importance of raw water chemistry, natural organic matter (NOM) concentration and type, and the chemistry of coagulants. Mineral and organic particles may be stable in water due to electrostatic charge interactions, hydrophilic effects, or to steric interactions from adsorbed macromolecules. NOM rather than particles initially in water supplies can control coagulant dosages and selection. MOM consists of a mixture of various organic compounds including hydrophobic (humic and fulvic acids) and hydrophilic fractions. The negative charge and chemical structure of the hydrophobic acids affect chemical reactions with coagulants, particularly metal based coagulants. The removal of NOM with Al coagulants can involve hydrolysis, complexation, precipitation, and adsorption reactions. Specific ultraviolet absorbance (SUVA) can be used to estimate whether the NOM of a water is high or low in hydrophobic acids and to estimate removals of DOC by coagulation. Preozonation of water supplies containing algae may lead to microflocculation or impair coagulation depending on algae type, concentration and molecular weight of extracellular organic matter (EOM), and ozone dose.
Dual Wavelength Photometric Dispersion Analysis of Coagulation and Flocculation
Authors: Matsui Yoshihiko , Tambo Norihito , Ohto Tokio , Zaitsu Yasushi
Published: May 2018

A technique to evaluate the coagulat ion/flocculation process on fluctuating light intensity transmitted through a flowing suspension has been developed recently for online monitoring in a flocculation system. In this paper, the authors tried to expand this technique to perform direct evaluation of floc size, settling velocity, and residual color after aluminum coagulation from the fluctuating light absorption using dual wavelengths. A theoretical study was carried out to establish the data handling algorithms for the evaluation of the above mentioned values from the fluctuating light absorbance. Two specific wavelengths were selected at near infrared and ultraviolet regions in order to characterize suspended matters and soluble colored organics. The usefulness of the proposed theory was verified in a series of batch coagulation tests with a newly developed dual wavelength photometric dispersion analyzer (DPDA). With an improved high precision photometer and data processing ci rcuits, the extent of color colloid removal can be estimated at the beginning stage of coagulation/flocculation. The algorithms for the evaluation of floc size were calibrated and verified in flocculation experiments with micro photography. Flocculation and sedimentation experiments showed that settling velocity was successfully estimated by the proposed algorithms.
Management and Institutional Aspects
Authors: Tyson J. M. , Guarino C. F. , Best H. J. , Tanaka K.
Published: May 2018

The paper addresses the general issue of the progressive, worldwide increase in urban pollution against the background of policy, regulation and institutional development. It is evidenced that society as a whole has not learnt from early European experience but has followed the same route and realised the same problems as the phenomenon of urbanisation has spread round the world. Thus the pollution problems now experienced in, for example, Sao Paulo in Brazil are essentially the same as those experienced in Manchester in the UK 150 years ago and, interestingly, but disappointingly, the solutions are also seen to be essentially the same. Examination of the development of environmental policy at a national level shows this to be an approach developed in the 1970s and notes the need for the inclusion of environmental economics at regional, national and global levels if the true environmental costs of particular policies and actions are to be determined. On regulatory frameworks the paper considers the relative merits of various management approaches including that of the Environmental Quality Objective and the Uniform Emission Standard; methods of achieving public involvement to influence the performance of the appropriate organisations are considered in the section on Institutional frameworks.
Coordination Between the Operation of the Sewerage Network and the Wastewater Treatment Plant: Demonstration of Different Strategies in Halmstad, Sweden
Authors: Hernebring Claes , Falk Jan
Published: May 2018

The strategies developed by the city of Halmstad, Sweden, to improve coordination between the operation of the sewerage network and the wastewater treatment plant are outlined
Storm Water Loading of Greater Copenhagen Sewage Treatment Plant
Authors: Hansen O. B. , Jacobsen C. , Skat Nielsen P.
Published: May 2018

Copenhagen's plans to cut pollution loads from combined sewer overflows involves increased storage capacity in the sewer system, real time control of that system, and increased hydraulic loading for the treatment plant. Modelling studies have been used to examine the consequences.
Settleable Solids in a Combined Sewer System: “Settling Characteristics – Pollution Load – Stormwater Tanks”
Authors: Michelbach S. , Wöhrle C.
Published: May 2018

Sedimentation and transportation of mineral and organic pollutants in combined sewer systems are not completely understood. For better understanding, samples of sediment, slime and urban runoff were taken from the combined sewer system of Bad Mergentheim. The settling velocity of settleable solids was measured with a settling apparatus. Typical settling curves for sediment, slime and wastewater were put together. Some of the samples were analysed for heavy metals and organic micropollution to see the relationship between settling velocity and the load of heavy metals of settleable solids. The gained data are of interest for the design of clarifier tanks for stormwater treatment.
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.
Ecotoxicological Effects of Urban Drainage: A Few Proposals Based on Results Obtained in Similar Situations
Authors: Vindimian Eric , Garric Jeanne
Published: May 2018

Applications of ecotoxicological testing are described that demonstrate the methods potential for monitoring urban storm drainage impacts.
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.
Comparison of Poliovirus Detection in Water by Cell Culture and Nucleic Acid Hybridization
Authors: Enriquez Carlos E. , Abbaszadegan Morteza , Pepper Ian L. , Richardson Kenneth J. , Margolin Aaron B. , Gerba Charles P.
Published: May 2018

The nucleic acid hybridization technique has been used to detect viral nucleic acid in environmental water samples. This type of assay, in contrast with tissue culture assays, may not distinguish between viable and non-viable viruses. We evaluated, by comparison with tissue culture infectivity assay (plaque forming method), the ability of the gene probe assay to detect viable poliovirus 1 (LSc) in well water, autoclaved well water, filter-sterilized well water and autoclaved phosphate buffered saline kept at 37° C and 15° C for 75 days, and in dechlorinated tapwater held at room temperature. A gradual decline in numbers of poliovirus was observed in all of the samples by cell culture assay. With the exception of autoclaved well water and phosphate buffer samples, a parallel decline in virus detectable by gene probe occurred in all other water samples.
The Efficiency of Water Treatment and Disinfection by Means of Ultraviolet Radiation
Authors: Sobotka J.
Published: May 2018

Advantages and disadvantages of various water disinfection methods are discussed. The report examines the effectiveness of combined chlorine treatment and UV irradiation method of water disinfection and describes methods of determining UV radiation intensity, α absorption coefficient and radiation dose by means of measuring equipment constructed by the author. The α absorption coefficient dependence on the colour and turbidity of water exposed to radiation is defined. Enchytraeus albidus was applied as bioindicator in UV radiation intensity and disinfection effects measurements. The influence of UV radiation on microbiological, physical, chemical, and toxicological properties of water was determined. Prototype devices for water disinfection with UV radiation were made.
Reduction of Microbial Levels in Sewage Effluents Using Chlorine and Peracetic Acid Disinfectants
Authors: Morris R.
Published: May 2018

The application of the EC Bathing Water Directive to the quality of marine waters used for recreation in the UK has shown that a substantial number of popular bathing places are contaminated with sewage and sewage effluent. The presence of microbes at levels in excess of the EC Directive standards has resulted in a commitment by UK water companies to invest heavily in the treatment of sewage at coastal locations prior to sea discharge. This study reports on the bench scale disinfection of secondary effluent using disinfectants based on chlorine and peracetic acid. Under the experimental conditions used, both bacteria and viruses were reduced substantially by a chlorine-based disinfectant. The reduction of bacteria by a peracetic acid compound was at least as good as that with the chlorine material but virus reduction was markedly lower.
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.
Addressing Nonpoint Sources of Water Pollution Must Become an International Priority
Authors: Duda A. M.
Published: May 2018

The nature and significance of nonpoint sources of surface and groundwater pollution are examined in this review. Examples are given from across the globe illustrating extensive economic, environmental, and human health damage from these diffuse sources. Agricultural sources, both subsistence farming and irrigated cropland, were found to cause the most widespread water quality problems worldwide. In the least developed nations, areawide releases of human sewage – especially near rural groundwater wells and in burgeoning urban areas – cause the most serious damage with an estimated one billion people suffering from waterborne diseases at any one time. In Europe, the former Soviet Union, and North America, leaking hazardous waste sites, contaminated sediments, and atmospheric deposition of acidifying and toxic substances pose complex challenges in addition to the agricultural pollution sources; and transboundary pollution abatement to restore large waterbodies is becoming a priority for foreign aid assistance. Institutional and cultural barriers to pollution abatement can be overcome by including interventions as integral parts of sustainable economic development initiatives. Through a comprehensive, ecosystem-based approach to water resources management, progress in controlling nonpoint source pollution can be made.
Diffuse Pollution in the Lagoon of Venice
Authors: Bendoricchio G. , Di Luzio M. , Baschieri P. , Capodaglio A. G.
Published: May 2018

The hypertrophic conditions of several confined areas in the Lagoon of Venice are but one of the consequences of nutrient discharges from its drainage basin. The monthly distribution of these loads, as well as their spacial subdivision among different tributaries of this characteristic water body, directly affect the growth cycle of macroalgae in it. The magnitude of these loads cannot be precisely measured by direct methods, however, it can be estimated by simulation with appropriate models. A comprehensive study aimed at the determination of these loads is under way as part of a larger intervention program to restore the physical and ecological equilibrium of the Lagoon. This paper focuses on the results of the simulation of diffuse loads generated in the Lagoon watershed. These results were obtained by interfacing a geographical information system (GIS) of the watershed and two models simulating respectively urban and agricultural diffuse pollution. Diffuse loads are then compared with the corresponding point sources to evaluate their relative contributing role in the dystrophic behavior of the Lagoon. The relative importance of diffuse sources is discussed with particular reference to time and space variability of the loads.
Dissolved Oxygen Characteristics of Wisconsin Streams
Authors: Greb S. R. , Graczyk D. J.
Published: May 2018

Dissolved Oxygen (DO) was continuously monitored at nine rural stream sites throughout Wisconsin. Both cold and warmwater sites had similar mean annual mean DO concentrations. DO minima were due to nighttime respiration and storm runoff with the storm losses being the most severe. A majority of DO standard violations (<5.0 mg/l) took place when daily mean water temperatures were above 20°C. Violations were more frequent at warmwater sites, even though coldwater sites were generally found to be more undersaturated.
Pahs in Atmospheric Particulate in the Area of Italian Scientific Base in Antarctica
Authors: Caricchia A. M. , Chiavarini S. , Cremisini C. , Fantini M. , Morabito R. , Perini A. , Pezza M.
Published: May 2018

Data on PAH levels in atmospheric paniculate were determined in the frame of the environment protection activities during the VI Italian Expedition in Antarctica. Samples were collected at the four cardinal points at about 200 metres from the central point of the Italian scientific base. Results are related to basic meteorological parameters, operating parameters and fuel consumption of the waste incinerator, power generators and other engines.

Data show low levels of the individual PAH (95% in the range 1-50 pg/m3) confirming the absence, up to now, of relevant contamination from Italian base.

On the basis of these preliminary results, monitor program will continue in the future expeditions in order to keep undercontrol the potential PAHs sources.
Degradation of Algal Exudates by Mixed Bacterial Biocenoses
Authors: Hambsch B. , Werner P. , Mäckle H. , Frimmel F. H.
Published: May 2018

In the frame of a research project concerning regrowth problems a water utility at Lake Constance is involved. For this plant it was interesting to find out which effect is exerted by organic products released from algae living in the lake water. Therefore model experiments were carried out using two different algal cultures in the stationary phase, where the algae were carefully separated by filtration. From these extracellular organic carbon solutions (exudates) dilutions were prepared using highly purified deionized water. These were tested for their ability to support bacterial growth by adding a mixed bacterial biocenosis after sterile filtration and monitoring growth curves by turbidity measurements, a method developed at the DVGW-Research-Center in Karlsruhe to judge drinking water with respect to its regrowth potential. It was shown that the exudate from a Haematococcus culture is very growth stimulating, though the substrate concentration analyzed as ∆DOC was very low. In contrast the exudate from a Stephanodiscus culture gave a very low growth response. The effect of the Stephanodiscus culture for the drinking water plant at Lake Constance is much more important because Stephanodiscus is a species common in Lake Constance whereas Haematococcus is not.
Pollutants and Contaminants
Authors: Goldberg E. D.
Published: May 2018

Marine pollution events have most often been identified by a catastrophe as opposed to rational scientific deduction. Herein I examine three instances where alterations to the marine environment may result in a loss of resources, either public health or the structure of marine ecosystems: the entry of biostimulants leading to eutrophication; the entry of artificial radionuclides; and the entry of plastics. The introduced materials are increasing in flux, have long residence times, and have known impacts upon living systems.
Transport of Particles Contaminated with Cesium Radionuclides into the Sediment of Lake Constance
Authors: Richter Th. , Schröder G. , Kaminski S. , Lindner G.
Published: May 2018

Three sediment cores taken at positions in Lake Constance strongly influenced by the river Rhine and one core taken at a position less influenced by this most important tributary were investigated with respect to the depth distribution of Cesium radionuclides in order to follow up transport processes of contaminated clay particles from the catchment system into the lake. In the depth distributions of Cs-137 well resolved maxima from the Chernobyl fallout and from the nuclear weapons testing fallout were found. Additionally, the high-water event of 1987 is reflected by the depth distributions of Cs-137 at the positions influenced by the river Rhine. The total inventories of Cs-137 activity from the Chernobyl fallout and the nuclear weapon testing fallout are higher compared to the input across the water surface at the positions influenced by the river Rhine, indicating the importance of fluvial input.
Associations between Polychlorinated Biphenyls and Suspended Solids in Natural Waters: An Evaluation of the Uptake Rate by Particles
Authors: Thibodeaux L. J. , Valsaraj K. T. , Reible D. D.
Published: May 2018

The study of the partitioning of PCBs and similar hydrophobic organic chemicals between solid and aqueous phases, such as suspended particles and the water column, has normally been approached from an equilibrium thermodynamic point of view. The kinetics of the uptake process have received some study but this has been limited. This paper presents a rationale for the importance of HOC uptake kinetics. A simple kinetic model is developed and applied to PCB in suspended particles and surface waters. It describes, in practical terms, many of the reported behavioral characteristics of Kd, the partition coefficient, observed both in the laboratory and in the field.
Sediment Studies Provide Key Information on the Need to Treat Sewage Discharged to Sea by a Major Canadian City
Authors: Chapman P. M. , Arthur A. D. , Paine M. D. , Taylor L. A.
Published: May 2018

Relatively untreated (screened) municipal wastes from the City of Victoria, B.C. and environs are discharged to the sea as effluent from two long outfall pipes, only one of which (Macaulay Point) discharges to a depositional zone. Sediments along transects away from the Macaulay Point outfall were collected and the following parameters determined: contamination (selected chemicals of concern), toxicity (polychaete survival and growth, amphipod survival, and bivalve larvae abnormalities), and benthic infaunal community structure. Significant sediment contamination was restricted to within 100-400 m of the outfall with the exception of high PAH contamination due to the shipwreck of a collier in 1891. Sediment toxicity was restricted to effects on growth and development, also within 100-400 m of the outfall; survival was near control levels even at the outfall terminus. Benthic infaunal community structure indicated “moderate pollution” within 100 m of the outfall and showed a classic organic enrichment pattern of increasing species richness and lower abundance with distance from the outfall. Overall, the impact of the outfall on the sediments is minimal, highly restricted in extent, and not of major environmental concern. A public referendum, conducted after the release of this and of other scientific studies, resulted in the deferral of primary effluent treatment.
Cleaning Contaminated Sediments by Separation on the Basis of Particle Size
Authors: van Rijt C.
Published: May 2018

In the Netherlands large quantities of contaminated sediment have to be dredged. Because it cannot be relocated directly in the marine environment, the dredged material must be placed in special contained depots which are expensive to construct. In 1989 a programme to reduce the volume of storage space required was started. This paper includes the results of research into the physical aspects of sediment cleaning.

Heavy metals are often found in the silt fraction, while organic micro pollutants occur in the silt fraction and sometimes also as tar particles in the sand fraction. The sediment can be cleaned by physical means or by the selective separation of some of the contaminants by froth flotation.

Research into the efficiency of using separation on the basis of particle size to clean contaminated sediments from five different sites and also the experience gained during three sediment clean-up operations, indicated that positive effects could only be achieved in sandy sediments. In some cases, owing to the presence of tar particles in the sediment, the quality of the sand fraction was not improved after separation in hydrocyclones. They can be removed from the sand fraction by flotation. Recent developments in selective separation by means of froth flotation, using equipment specially designed for the fine fraction, are promising.

The use of duo-flocculants has a favourable influence on the consolidation behaviour of the fine fraction after separation.
The Behaviour of Mercury within a Contaminated Tidal River System
Authors: Bubb J. M. , Williams T. P. , Lester J. N.
Published: May 2018

The historical emission of mercury from a municipal sewage treatment works, which discharges to a lowland river, has resulted in a 17 km contamination plume, the nature of which is strongly dependent upon river bed morphology. Significant variations occur in the spatial distribution of mercury concentrations over very short distances as dictated by sediment type, channel morphology, hydrology and sedimentation rates. The major sedimentalogical process is one of net deposition of paniculate matter rather than downstream transportation, which has buried contaminated sediment beneath a cleaner overlay. The behaviour of methylmercury within the sediment system is not dependent solely upon total mercury concentrations but instead is governed by a complex interplay between sediment redox potential, temperature, sulphur chemistry and the nature of bacterial communities. Detectable levels of methylmercury were confined to the uppermost 40 cm of sediment with peak loadings occurring 4-8 cm from the sediment/water interface. Methylmercury concentrations vary seasonally with minimum loadings in the autumn and highest concentrations in the summer. The distribution of methylmercury within the sediment compartment closely mirrors that of the mercury tolerant bacteria but in-situ and laboratory based experiments have also linked seasonal variations in methylmercury levels to changes in temperature.
Advancing ICA Technology by Eliminating the Constraints
Authors: Olsson Gustaf
Published: May 2018

Experts from 16 countries were surveyed to provide an overview of the current status, the constraints and the future prospects for instrumentation, control and automation in water and wastewater treatment and transport. Their responses are summarised.
Realizing the Benefits of Enterprise-Wide Computing
Authors: Sweeney Michael , Manning Alan
Published: May 2018

This paper is a case history on the benefits the city of Indianapolis has been able to realize from incorporating an enterprise-wide model for approaching automation at their two Advanced Wastewater Treatment (AWT) Plants. Emphasized is the importance of strategic planning, performance measures and human factors associated with the suggested implementation of applied technology. Also discussed are the results, thus far, with the implemented portions of the plan. A framework is summarized for other municipalities to use as a guide to applying virtually any automation technology.
Use of Part-Time Unmanned Operation at a Large Wastewater Treatment Plant
Authors: Lumley Doug J. , Sahlberg Kent-Åke , Haraldsson Jan
Published: May 2018

The use of part-time unmanned operation at the Göteborg Regional Sewage Works, Göteborg, Sweden (average flow 325 000 m3/d) is described. Outside normal working hours, a two-man standby crew is responsible for the operation of the plant. The plant's SCADA system and special equipment used by the standby crews (e.g. pagers, cellular telephones, Notebook PC) inform the crews when an alarm has been generated. The standby crew can then react to the alarm, often by logging into the SCADA system and taking appropriate actions. More serious disturbances require visiting the plant. Use of the standby system has only a marginal effect on effluent quality and has not affected effluent compliance. A cost comparison of the standby system with a traditional full-time manned system indicates annual savings of about 1 350 000 SEK.
An Overview of the Trunk Scheduling System for the London Ring Main
Authors: Burnell David , Race Julia , Evans Phil
Published: May 2018

The London Water Ring Main is one of UK's largest water investments. It will eventually carry half of London's water and greatly increase the flexibility of London's trunk distribution network. The Trunk Scheduling System is a core part of decision-support for the enhanced network. It has been written to help Operational Controllers make best use of that extra flexibility.

Cost-effective operation makes best use of the cheapest treatment works, lowenergy-loss routes and off-peak tariffs. These need to be combined to meet projected diurnal demands in over 50 zones and leave each of some 20 service reservoirs at a target end volume, whilst taking no more than the declared “reliable output” from each of 10 works. The schedule proposed must be hydraulically viable as well as cheap. Most route constraints arise from pressure limits (so as not to burst mains or leave customers without water). Hydraulic constraints are non-linear and require on-line hydraulic intelligence as the schedule is developed.

The key idea is to regard a schedule as a series of “operating regimes”, each of which is applied for a specified duration. Each regime applies within a particular timeslice. It comprises settings for each pump in the network, together with its implications: a unit cost and the effect of those settings on each source and each reservoir under hydraulic equilibrium. Trunk Scheduling provides a series of modules to answer the questions:which regimes (of the billions possible) should make up the schedule?how long should each selected regime be applied for?in which sequence should the chosen regimes be applied?
An Operational Information Database Based on the Automated Processing of Time Series Data Available from Telemetry Control Systems
Authors: Casey R. J. , Grinney S. A.
Published: May 2018

The paper describes the development and subsequent management of a central database of operational information based largely on the automated processing of time series data retrieved from the Company's telemetry control systems.

Following the implementation of the system, both the quality and quantity of processed statistics available to operational managers has been greatly enhanced above the level of information originally recorded by manual methods. Also significant process modelling systems have been introduced utilising this information to improve operational efficiency.

Key to the success of the system has been the comprehensive provision of facilities to quickly and effectively validate the data, together with the facilities provided to ensure that the configuration of the database accurately matches and tracks configuration changes to the field network. The paper examines these functions in some detail.
Water Demand Forecasting by Memory Based Learning
Authors: Tamada Takashi , Maruyama Minoru , Nakamura Yasuaki , Abe Shigeru , Maeda Kazuo
Published: May 2018

Recently, a “memory based” approach towards various kinds of problems has been proposed. The underlying principles of the memory based approach are : (1) storing past examples in a memory. (2) searching “near” examples to a given input in a memory. In this paper, we apply the memory based approach to water demand forecasting, and present a hybrid method which consists of MBL (Memory Based Learning) and the conventional multiregression. In the memory based method, the distance metric is crucial. In our method, the local distance metric is defined from examples when an input data is given, then the neighborhood of the input is determined based on the distance metric. If there exist examples within the “neighborhood” of the input data, then the forecast is given by MBL. Otherwise, local multiregression is used. We applied this method to the daily water demand forecasting. The forecasting results by our method are approximately 5% better than those by the multiregression method. Especially, when there exist past examples in the neighborhood, namely in the case where MBL is applicable, the results are approximately 10-30% better than those by the conventional multiregression.
Model Calibration for the High-Purity Oxygen Activated Sludge Process – Algorithm Development and Evaluation
Authors: Yuan Weibo (Weber) , Okrent David , Stenstrom Michael K.
Published: May 2018

A model calibration algorithm is developed for the high-purity oxygen activated sludge process (HPO-ASP). The algorithm is evaluated under different conditions to determine the effect of the following factors on the performance of the algorithm: data quality, number of observations, and number of parameters to be estimated. The process model used in this investigation is the first HPO-ASP model based upon the IAWQ (formerly IAWPRC) Activated Sludge Model No. 1. The objective function is formulated as a relative least-squares function and the non-linear, constrained minimization problem is solved by the Complex method. The stoichiometric and kinetic coefficients of the IAWQ activated sludge model are the parameters focused on in this investigation. Observations used are generated numerically but are made close to the observations from a full-scale high-purity oxygen treatment plant. The calibration algorithm is capable of correctly estimating model parameters even if the observations are severely noise-corrupted. The accuracy of estimation deteriorates gradually with the increase of observation errors. The accuracy of calibration improves when the number of observations (n) increases, but the improvement becomes insignificant when n>96. It is also found that there exists an optimal number of parameters that can be rigorously estimated from a given set of information/data. A sensitivity analysis is conducted to determine what parameters to estimate and to evaluate the potential benefits resulted from collecting additional measurements.
Control of BNR Processes by Regulation of the VFA/M Ratio
Authors: Armiger William B. , Lee George J. , Schwegler Benedict R. , Mah Terry J.
Published: May 2018

Diurnal variation is characteristic of nearly all POTWs currently in operation. Equalizing the organic load to the process can significantly benefit the performance of the biological treatment process. The potential benefits of flow equalization have been recognized for over 20 years, although subsequent work has not been able to demonstrate reliable engineering designs to capitalize on these theoretical benefits. During the past decade, stricter environmental regulations have increased the interest and investment in nutrient removal processes. The successful development of Biological Nutrient Removal (BNR) treatment processes has accelerated this process. The data in this paper demonstrate that the ability to accurately measure and track biological reactions is crucial to the ability to equalize plant loadings. It is important to reiterate, in this regard, that the “bioreactor” which carries out the treatment reactions is a living cell and not a concrete tank. This manuscript presents new technology for the control of BNR treatment plants based upon direct measurements of cell metabolic activity, and presents results of preliminary experiments to control the waste load to biomass ratio independent of hydraulic flow fluctuations.
Fuzzy Control of a Dynamic Activated Sludge Process for the Forecast and Control of Effluent Suspended Solid Concentration
Authors: Tsai Y. P. , Ouyang C. F. , Wu M. Y. , Chiang W. L.
Published: May 2018

The effluent total BOD (or COD) concentration of the activated sludge process (A.S.P.) usually increases with suspended solid concentration. How to reduce effluent S.S. concentration, therefore, is the key issue of treatment efficiency for A.S.P. The varied return sludge and influent flow rate are two major operational factors of those affecting effluent S.S. concentration. However, the wastewater flow rate and substrate concentration in municipal wastewater treatment plant, due to the differences of city scale and life style, are significantly time-varied every day. Based on the above, the purpose of this study is to control in timely fashion return sludge flow rate with the variation of influent flow rate to minimize effluent S.S. concentration and meanwhile decrease the effluent total BOD (or COD) concentration. The fuzzy control theory is utilized in this study to forecast and control effluent S.S. concentration and further predict the MLSS concentration in aeration tank. It reveals that the inferred control strategies not only enable one to decrease effluent S.S.
Simultaneous Removal of Nitrogen and Phosphorus in Intermittently Aerated 2-Tank Activated Sludge Process Using DO and ORP-Bending-Point Control
Authors: Sasaki Kousei , Yamamoto Yasuji , Tsumura Kazushi , Hatsumata Shigeru , Tatewaki Masahiro
Published: May 2018

The 2-tank intermittent aeration method is an anaerobic-aerobic activated sludge process of time-sharing type in which 2 complete mixing reaction tanks are connected in series, and aeration and agitation are periodically repeated in each tank. We have developed a new control system for the process which can secure anaerobic, anoxic and aerobic conditions through a combination of DO and ORP-Bending-point (corresponding to termination of denitrification) emergence time control. In the 1st tank, nitrification and phosphorus uptake occur in the aeration period, followed by denitrification and phosphorus release in the agitation. The 2nd tank performs nitrification and phosphorus uptake in the aeration and denitrification in the agitation. One cycle of aeration and agitation is approximately 2 hours. This control system was applied to the test plant (influent flow rate: 225 I/day) for two months under the conditions of HRT 16 hours and temperature 20 ±2 °C. We achieved stable and high removal ratios: TOC 94.9 %, T-N 89.4 %, and T-P 95.5 %. We also investigated the mechanisms of nitrogen and phosphorus removal and their material balance.
The Usefulness of On-Line Monitoring in Effecting Savings in Combined Biological and Chemical Removal of Phosphorus in Activated Sludge Plants
Authors: Lotter L. H. , Pitman A. R.
Published: May 2018

On-line analyzers to monitor the effluent levels of ammonia and phosphate have been installed at all four nutrient removal activated sludge plants in Johannesburg. The data from these instruments is transferred to a SCADA system for control purposes. The on-line system is supplemented by laboratory data, which is stored on a separate computer system. A combination of this data is used for routine operational control.

Dissolved oxygen probes are installed in the aerobic reactors of all plants and are used for aeration control. Automatic aeration control has recently been installed at one of the plants. In this paper some experience with on-line monitoring is discussed in terms of its usefulness and cost savings achieved. Savings of 1 million US $ in the purchase of phosphate precipitation chemicals have been achieved in the current financial year as a result of more efficient operational control.
INTEGRATED AND STOCHASTIC FEATURES OF URBAN DRAINAGE SYSTEMS
Authors: Harremoës P.
Published: May 2018

An analysis has been made of the uncenainty of input parameters to detenninistic models, with emphasis on the models for the sewer system. For each parameter a sensitivity analysis and for all the parameters a Monte Carlo analysis has been made. The analysis reveals a very significant uncenainty that can be decreased; but cannot be eliminated as significant to engineering application. Stochastic models have a potential for dealing with these uncertainties. That applies also to the treatment plant and to the receiving water models. The three components in the system have been analysed as a whole. Examples show that an integrated analysis is required in order to find economically optimised solutions that comply with environmental standards.
PROCESS DESIGN OF ADVANCED STORAGE-TREATMENT FACILITIES FOR CSO CONTROL
Authors: Zukovs George , Pisano William
Published: May 2018

Increasing focus on the abatement of combined sewer overflow has produced considerable interest in new and innovative control approaches. Particular attention has fallen upon the application of high rate physical-chemical processes as part of integrated CSO storage treatment schemes.

The extensive experience gained during a recent study in Metropolitan Toronto, Canada is used to describe and illustrate a systematic planning and preliminary design procedure for high rate CSO treatment facilities. The procedures includes five basic steps starting with catchment characterization and process flow sheet development and including process evaluation studies, comprehensive modelling and estimation of costs and performance.
JOINT CONSIDERATION OF SEWERAGE SYSTEM AND W ASTEW ATER TREATMENT PLANT
Authors: Otterpohl Ralf , Freund Martin , Sanz Juan Pablo , Durchschlag Andreas
Published: May 2018

The total efficiency of combined sewerage systems and wastewater treatment plants (WTP) sbould be considered. By an overall planning procedure the benefits of the whole system can be optimized. For the estimation of the system behaviour with different rain events, computer simulations of the sewerage system including storage tanks and the treatment plant have to be carried out. The two systems are not coupled mathematically allowing separate simulation. Hydrographs of different scenarios computed for the sewerage system can be used for simulations of the WTP.

For comparing the effects of different throttle flows on the treatment plant an example bas been simulated. In this example the BOD5 and phosphorus loads could be reduced with a higher throttle flow. The large difference in total discharges from combined sewerage without storage tanks and with well-dimensioned tanks could also be demonstrated.
MODELLING OF FULL-SCALE WASTEWATER TREATMENT PLANTS: HOW DETAILED SHOULD IT BE?
Authors: Watson Bruce , Rupke Mark , Takács Imre , Patry Gilles
Published: May 2018

Dynamic mathematical modelling of full-scale wastewater treatment plants requires an optimal level of detail to be accurate, effective, but still manageable. Single process models tend to oversimplify the complexities of a large-scale plant and result in erroneous calibrated parameter values or limited predictive power for the model – on the other hand, modelling of every process and process unit is usually impractical, since it cannot be supported by reliable plant data, and requires prohibitive sampling costs and effort.

Level of aggregation, settler dimensionality and reactivity, and plug-flow hydraulics were investigated with the help of a sophisticated dynamic modelling package. The results show that there is no general rule or global ‘optimal level’ of modelling – the required modelling detail is a function of influent flow and loading levels, and processes to be simulated (BOD removal, nitrification-denitrification, biological phosphorus removal, settling). In the case of real-life plants, supportable modelling level is often constrained by data availability and reliability.