bluuebunny/crossref_metadata_2025 huggingface dataset:
Phosphorus removal in ponds
Authors: Lopez Ernesto R. , Surampalli Rao Y. , Banerji Shankha K. , Pycha Charles J.
Published: May 2018

The municipal lagoon treatment systems which remove phosphorus by chemical addition are the subject of this special study. The objectives of this study were to determine the degree of success of lagoon treatment systems in removing phosphorus and to identify any operational problems. In order to obtain basic data for this study, thirty-two lagoon treatment systems in Michigan and Minnesota were investigated. Chemicals typically used for phosphorus removal include metal salts such as aluminium sulfate (alum), ferrous and ferric chloride, lime, and various polymers. The overall experience with these lagoon systems is that the technology, in its various configurations, has been working very well. Of the thirty-two lagoon treatment facilities reviewed, only two facilities were having problems meeting consistently the effluent phosphorus limits. Generally, the permitted effluent phosphorus limit is 1 mg/l. The influent phosphorus concentrations varied between 0.5 and 15 mg/l. Alum and ferric chloride applications produced consistently high quality effluents while lime applications were not as effective in removing phosphorus. None of these lagoon treatment systems experienced problems with build-up of sludges to levels which affected the effluent concentrations. Accumulated amounts were an inch or less per year, consistent with solids build-up in the primary lagoon cells.
Cryptosporidium removal during water treatment using dissolved air flotation
Authors: Hall T. , Pressdee J. , Gregory R. , Murray K.
Published: May 2018

The occurrence of the protozoan parasite Cryptosporidium parvum in water supplies, and the resultant outbreaks of cryptosporidiosis in the UK and USA, have led to concern over the ability of conventional water treatment processes to remove Cryptosporidia from water sources. Large scale pilot plant trials of water treatment have been carried out in the UK to establish the degree of removal that can be achieved by a range of treatment processes, including dissolved air flotation, and to compare the performance of different treatment options. Results from part of these trials are presented in this paper. These results suggest that well operated chemical coagulation based treatment, using either dissolved air flotation or floc blanket clarification, should be capable of achieving removal of Cryptosporidium oocysts of over 99%. There was no evidence of differences in performance between the different types of filter media investigated. The risk of increased Cryptosporidium concentration in the filtered water will increase as filtrate turbidity increases. However, other factors such as high coagulant metal-ion concentration in the filtered water, or a sudden increase in clarified water turbidity, without any increase in filtered water turbidity, may also indicate treatment problems and associated risk from Cryptosporidia. Recycling of backwash waters may also increase the risk.
Modified vortex separator and UV disinfection for combined sewer overflow treatment
Authors: Boner M. C. , Ghosh D. R. , Harper S. R. , Turner B. G.
Published: May 2018

This paper presents the results of a study to evaluate the efficiency of a modified vortex separator (MVS) and an ultraviolet (UV) disinfection unit for direct treatment of combined sewer overflows (CSOs). The MVS included dissolved air and coagulant addition. The effluent from the vortex separator was disinfected continuously using UV light. Bench-scale tests were performed on CSO samples to screen various coagulants and operating pressures for dissolved air. Field tests were performed at the CSO pilot facility where simulated as well as actual storm-generated overflow events were studied.

Performance comparisons between the MVS and other CSO treatment technologies are presented. Results indicate that the MVS achieves pollutant removals superior to conventional sedimentation for the same surface loading rates, or can be hydraulically loaded several times higher than sedimentation to achieve the same results. The results also indicate that the MVS significantly improved solids concentration capability when compared to the conventional operation of the vortex separator. UV disinfection performance was dependent on TSS removal and showed promise for full scale implementation when combined with MVS treatment.

This project was sponsored by the Water Environment Research Foundation and was a collaborative effort between ten participating organizations including the US Environmental Protection Agency (EPA), municipalities, consulting firms and equipment manufacturers.
Microbiological-epidemiological study of selected marine beaches in Malaga (Spain)
Authors: Mariño F. J. , Moriñigo M. A. , Martinez-Manzanares E. , Borrego J. J.
Published: May 2018

Two beaches at Malaga, Spain, (one clearly polluted, one a “blue flag” beach) were studied to establish their microbiological status; epidemiological studies were carried out to identify any association between use of the beaches and enteric or non-enteric diseases. Correlations were then sought between the results of the two studies. Skin infections were found to be associated with seawater levels of P. aeruginosa, C. albicans and A. hydrophila, which could be related to faecal contamination.
Association of staphylococcal skin infections and swimming
Authors: Charoenca N. , Fujioka R. S.
Published: May 2018

An association between using coastal waters for recreation and staphylococcal skin infections has been reported by canoe paddlers and several physicians in Hawaii. A retrospective epidemiological/microbiological monitoring study was undertaken to determine the association between S aureus skin infections in youngsters (4 months to 16 years of age) and their exposure to recreational use of coastal waters. Telephone interviews were conducted of 53 patients with such skin infections and 53 similar (controlled for age and sex) patients with no infection. A significant association between skin infection and water exposure was found, the odds showing that those developing skin infection caused by S aureus were 4 times more likely to have had a history of seawater contact than the control group. Moreover, the antibiotic sensitivity patterns and phage types of S aureus isolated from patients were similar to those isolated from seawater at bathing beaches.
Murray-Darling Basin Commission: a case study in integrated catchment management
Authors: Blackmore D. J.
Published: May 2018

This paper describes the Australian Murray-Darling basin experience in integrated catchment management, what has been achieved and what remains to be done. The basin water is shared by three states, but falls under the jurisdiction of four governments, that of the Commonwealth as well as the State governments. The critical development in recent years at the political and bureaucratic level was the establishment of a three-tier management structure that allows common interests to be developed, discussed, resolved and implemented. Two main problems had to be resolved before significant co-operative action could take place, namely the issues of water sharing between the states and the sharing of costs associated with Murray River salinity. A framework Salinity and Drainage Strategy was developed to address this, and is described.

This paper also describes the Natural Resources Management Strategy, the cornerstone of efforts to sustain the natural resources of the basin. The strategy emphasises community participation and empowerment. The problems identified, strategic aims to address these problems and the role of community action are detailed.
Who should get the water? Decision support for water resource management
Authors: Chapman R. A. , Manders P. T. , Scholes R. J. , Bosch J. M.
Published: May 2018

Increasing competition for water in South Africa is changing the management emphasis from one of supply to that of controlling demand. There are many possible alternative uses of water. The Catchment Resource Assessment Model (CRAM) is a tool which can help evaluate these alternative uses. CRAM has been designed to:

- be objective;

- be fair to all parties;

- balance social, environmental and economic benefits and costs, and

- be understandable to the educated non-specialist user.

Using water as a “currency”, CRAM simulates the impacts of land uses on hydrological, economic, environmental and social conditions in a catchment. The Crocodile River catchment is modelled in the current implementation of CRAM. Users have indicated their preference for familiar and well-tried submodels in CRAM, rather than new, unknown models.
Economic analysis of water resource development proposals in the Sabie River Basin
Authors: Hollingworth B. , Mullins D.
Published: May 2018

The Sabie River is an important river catchment in South Africa because of its ecodiversity, importance to the Kruger National Park, agricultural and afforestation potential and relatively undeveloped water resources. These resources are under stress from increasing irrigation and a burgeoning population. In the mid-eighties an intensive river basin study was undertaken to guide and promote sustained development. The studies described in this paper were undertaken in order to include economic criteria in development investment decision making. These studies were firstly, a macro-economic view which extended to sector analysis and secondly, a cost-benefit analysis of the proposals. The first found that the balance between economic growth and the demand for water takes place in an area which exhibits a dualistic and interdependent nature, between the Sabie River subregion with dynamic economic growth sectors, and the Sand River subregion with a small economic base but high population concentration. The study introduces the concept of investment absorption capacity which uses Gross Geographic Product as a proxy in a methodology that indicates the maximum capital that can, technically, be invested in water resource development in the area. The second part uses traditional cost-benefit analysis to determine the economically preferred proposals for development.
Removal of cryptosporidium by slow sand filtration
Authors: Timms S. , Slade J. S. , Fricker C. R.
Published: May 2018

Experiments have been performed to establish the effectiveness of slow sand filtration in removing Cryptosporidium oocysts from drinking water supplies. The technique was shown to be highly efficient, with better than 99.997% reduction in oocyst levels.
Removal and inactivation of cryptosporidium oocysts by activated sludge treatment and anaerobic digestion
Authors: Stadterman K. L. , Sninsky A. M. , Sykora J. L. , Jakubowskii W.
Published: May 2018

To determine the fate of Cryptosporidium parvum oocysts during wastewater treatment, a model of an activated sludge treatment plant was designed with a flow of 17 ml/min and a detention time of 6 hours. Samples of raw sewage were seeded with oocysts and primary and secondary effluents were analyzed for C. parvum using an immunofluorescent technique. To compare removal efficiencies of oocysts by various wastewater treatment processes, raw sewage, activated sludge, trickling filter and biodisc effluents were seeded with oocysts and settled for 2 hr and for the respective detention times. Sludge produced by a wastewater treatment plant and anaerobically digested at 37° C in a laboratory digester was also seeded with C. parvum oocysts. Oocyst inactivation was measured by excystation and direct counts. Removal of oocysts in primary and secondary sedimentation averaged 83.4% and 90.7% respectively. The total oocyst removal in sewage treatment averaged 98.6%. In comparison with other treatment processes, activated sludge had the maximum oocyst removal efficiency at 92%. The anaerobic digestion process inactivated 90% of the oocysts within four hours of exposure. 99.9% of the oocysts were eliminated by anaerobic digestion after 24 hours. This demonstrates that the activated sludge process and anaerobic digestion can be effective for the removal and inactivation of C. parvum oocysts.
Development of a test method for assessing inactivation of viruses by materials used in domestic plumbing
Authors: Colquhoun K. O. , Timms S. , Maddox A. , Fricker C. R.
Published: May 2018

To examine the virucidal effect of various materials used for tubing in domestic water supply systems, experiments have been carried out that examine the recovery percentages of five viruses allowed to flow through pipes made from “aged” samples of five plumbing materials. Most materials had only modest virucidal effect, but copper produced significant reductions in levels of all five viruses.
The development of a water quality management plan for the Mgeni River catchment
Authors: Howard J. R. , Ligthelm M. E. , Tanner A.
Published: May 2018

Located in the province of KwaZulu-Natal, South Africa, the Mgeni River catchment provides the potable water resources for nearly two million people, in an area of approximately 4 400 km2. The river system is well developed and impounded, but increasing population pressures in the catchment are placing greater demands on this critical water resource resulting in increasing loads of nutrients, faecal bacteria and suspended solids. Umgeni Water and the Department of Water Affairs and Forestry are developing an affordable and practically implementable plan to manage the water quality on an integrated catchment basis, encompassing demographic, land-use and management considerations. The development of the plan is discussed and information on the water management related issues provided. A multidisciplinary approach has proved essential, facilitated by the development of a GIS-based system to manage and utilize the information from the study. Establishment of communication links with interested and affected parties has been critical, as has the clarification of their roles and responsibilities in dealing with identified pollution issues. Future development within the catchment is considered and the implementation of the management plan is discussed against the background of the Reconstruction and Development Programme.
Bacteroides fragilis and Escherichia coli bacteriophages: excretion by humans and animals
Authors: Grabow W. O. K. , Neubrech T. E. , Holtzhausen C. S. , Jofre J.
Published: May 2018

The faecal excretion of somatic and male-specific coliphages, and phages of Bacteroides fragilis strain HSP40, by humans and a variety of animals has been investigated as part of research on indicator features of phages. Ninety human stool specimens were obtained from black and white male and female individuals varying in age from 6 months to 85 years. Sixty-five faecal samples from domestic animals including cattle, sheep, pigs, horses, dogs, cats, geese and rabbits, were obtained from various agricultural and domestic sources. The National Zoological Gardens in Pretoria kindly supplied 38 stool specimens from higher primates (gorilla, orangoutang and chimpanzee). Thirty-seven stool specimens from chacma baboons and vervet monkeys were obtained from the Zoological Gardens and our animal research centre. Five specimens of seabird droppings were obtained from the west coast of South Africa. The qualitative presence of phages was determined by an enrichment procedure followed by a plaque spot test. Double agar layer plaque assays were used to titrate phages. Bacteroides fragilis phages were detected in 13% of human stool samples, but not in any animal faeces. Somatic coliphages were detected in 54% of human, 56% of domestic animal, 57% of monkey and baboon, 53% of higher primate, and 60% of seabird specimens. Male-specific coliphages were detected in 26% of human, 90% of domestic animal, 76% of monkey and baboon, 63% of higher primate, and 20% of seagull faecal samples. Titres of phages in selected samples varied from undetectable by direct plaque assay to 4.5 × 106 somatic and 3.2 × 104 male-specific coliphages per gram of seabird droppings. Faecally polluted environments may, therefore, contain substantial numbers of somatic and male-specific coliphages of human and animal origin. The results confirm earlier observations that B fragilis phages can be used to distinguish between faecal pollution of human and animal origin.
Management of the Occoquan River basin: a 20-year case history
Authors: Randall C. W. , Grizzard T. J.
Published: May 2018

The high dam on the Occoquan River of Northern Virginia, United States of America, was constructed in 1957, forming a drinking water reservoir with a capacity of 37.1 × 106m3 formed by drainage from a 1 460 km2 watershed, and providing a safe yield of 189 251 m3 per day. Deteriorating water quality in the late 1960s led to a special “policy” for the watershed, designed to preserve the reservoir as a drinking water supply. Key provisions of the policy mandated replacement of the watershed's 11 publicly owned wastewater treatment works with a single advanced wastewater treatment plant (AWT), and establishment of the Occoquan Watershed Monitoring Programme. Early results from the programme established non-point nutrient pollution as a major cause of water quality deterioration and resulted in the implementation of non-point pollution controls throughout the watershed during the late 1970s. The AWT plant went on-line in July 1978. Continuous monitoring since 1973 has demonstrated both the necessity and the effectiveness of point and non-point nutrient controls for the preservation of the reservoir's water quality. The AWT plant provides excellent removal of organics and phosphorus, plus complete nitrification. The nitrates are discharged to the receiving stream to enhance conditions in the reservoir. Control policies include land-use management for the preservation of this essential water supply for 750 000 people in the Washington, D.C. suburbs. Land-use management decisions are based on the results obtained with a watershed-reservoir linked computer model which predicts water quality changes resulting from land-use changes.
Significance of indicator bacteria changes in an urban stream
Authors: Davis Ernst M. , Garrett M. Truett , Skinner Terri D.
Published: May 2018

An urban coastal stream, above tidal reach, and three municipal wastewater treatment plant effluents were analyzed for fecal coliforms, fecal streptococci and enterococci to determine the effect of dechlorination on those bacterial populations. Analyses were conducted during low and high flow periods from stormwater inflow. Improvement in bacterial water quality was found, principally due to municipality efforts to correct illicit connections and other sewerage system problems. Fecal coliform genera were identified and quantified. Regrowth of dechlorinated effluent bacteria was minimal.
The identification and human health significance of environmental aeromonads
Authors: Ashbolt N. J. , Ball A. , Dorsch M. , Turner C. , Cox P. , Chapman A. , Kirov S. M.
Published: May 2018

Aeromonads readily grow in waters, particularly if nutrified, to concentrations in excess of total coliforms. Strains of aeromonads can cause gastroenteritis and tissue necrosis. Several suspected virulence factors, such as haemolysins, cytotoxins and enterotoxins may be involved in their pathogenesis. Amongst the thirteen recognised hybridisation groups of Aeromonas, only five species were identified by eight phenotypic characteristics from 339 strains isolated from marine, fresh river or storm waters or from tertiary and sewage/primary effluents. The majority of strains (50%) showed atypical phenotypes, and 24% of 208 randomly selected strains were not identified as aeromonads with a genus specific 16S rDNA-targeted PCR. Most discrepancies occurred with A. schubertii phenotypes, none of which were identified as aeromonads by PCR. Marine waters contained the largest proportion of atypical phenotypes (45/67) of which 60%, compared to <20% for other water sources, were not identified as aeromonads by PCR. A. hydrophila was generally the predominant species identified (93/339), although A. caviae was more prevalent in tertiary treated sewage effluents. Freshwaters contained the largest proportion of aeromonads with haemolysin and/or enterotoxin activity, whereas cytotoxin activity was more prevalent from stormwater isolates. Freshwater strains of A. veronii biotype sobria and A. hydrophila appeared to be the most toxigenic. Furthermore, river sites downstream of sewage effluent release contained more aeromonads than sites immediately upstream of the discharge. Hence, there was a clear positive correlation between freshwater eutrophication and the presence of potentially virulent aeromonads, the majority of which were A. hydrophila and A. veronii which can most rapidly and accurately be identified by PCR.
Integrated cadastre (Inventory System) for pollution sources in the Danube basin in Yugoslavia
Authors: Marjanovic P. , Miloradov M. , Cukic Z. , Bogdanovic S. , Sakulski D.
Published: May 2018

The state of the art approach to environmental protection and management calls for the implementation of major multipurpose environmental protection systems and a wide scope of preventive measures. Since environmental protection falls within the scope of problems collectively known as “externalities” which justify government intervention, i.e. the implementation of the required measures, it is the responsibility of the government to ensure that adequate data is collected and analyzed prior to any decision making pertaining to environmental protection. It is this responsibility of the Government and the constitutional right of the people to live and work in a healthy environment that are the basis of the development of a Federal Integrated Cadastre of Polluters.

The integrated approach requires a substantial increase in the amount of information and data on which the planning decisions of the future will be based. It is this need for information and data necessary for the implementation of the state of the art forecasting, planning and management (decision making) that brought about the development of the Integrated Cadastre (Inventory) of Polluters in the Danube basin in Yugoslavia.

This paper presents the methodology used in the development of the integrated cadastre and gives a brief review of the structure of the information system used to manage the integrated cadastre.
Nutrient management at the catchment scale using a decision support system
Authors: Young W. J. , Farley T. F. , Davis J. R.
Published: May 2018

To effectively manage the nutrient status of waterbodies, an ability to predict the likely external nutrient loadings from both point and diffuse sources under present and future conditions is important. The processes of nutrient export and transport are very complex, and detailed data and knowledge of these processes are seldom available without lengthy and expensive investigations. As an alternative, estimates of average annual catchment nutrient loads can provide an initial basis for strategic decision making, and indicate where more detailed investigations would be most beneficial. The Catchment Management Support System (CMSS) is a PC-based programme that was developed to calculate average annual nutrient loads and to allow the effects of land-use changes and land management changes to be investigated with ease. In addition, the CMSS approach stresses the importance of wide community involvement in the decision-making process for catchment management. The CMSS package is described, including the nutrient load prediction model used and its data requirements and the features of the user interface. A discussion of the role of CMSS in the decision-making process is made with reference to the imminent development of Nutrient Management Plans for many Australian catchments.
Removal of PCR inhibiting substances in sewage sludge amended soil
Authors: Straub Timothy M. , Pepper Ian L. , Gerba Charles P.
Published: May 2018

Current methods for the detection of enteric viruses in soil involve elution of viruses from soil colloids using beef extract or other proteins. These eluates are then assayed in cell culture and observed daily for cytopathic effects (CPE). While this method is suitable for detection of enteric viruses by cell culture, these eluates contain humic acids and heavy metals that interfere with polymerase chain reaction (PCR) detection. Using beef extract eluates prepared from sludge amended soil, 10 different methods of eluate purification were evaluated for their ability to remove PCR inhibition and maximize sensitivity. The treatment method providing the greatest sensitivity of poliovirus detection by PCR was the combination of Sephadex G-50 and Chelex-100. Using this method 2 plaque forming units (PFU) could be detected after reverse transcription and 30 cycles of PCR. Thirty (30) cycles of seminested PCR were performed on these samples to verify nucleic acid sequences and increase sensitivity after the first 30 cycles of PCR. Using seminested PCR, sensitivity of detection using the Sephadex G-50 and Chelex-100 treatment method to 0.2 PFU. In addition to providing excellent sensitivity for viruses in sludge amended soils, this treatment method is relatively simple compared to other methods.
Enzymatic amplification of enteric viruses from wastewaters
Authors: Green David H. , Lewis Gillian D.
Published: May 2018

The challenge to use of enzymatic amplification for detection of waterborne viruses is the effective removal of a range of inhibitory components present in environmental samples. This study combines a number of individual processes to simultaneously concentrate and purify enteric viruses from wastewaters. The procedure of secondary concentration and purification, using chloroform extraction, polyethylene glycol precipitation, Sephadex G-200 gel filtration, and ultrafiltration, was shown to be 39 and 31% efficient in recovering enterovirus from raw sewage and oxidation pond effluent respectively, achieving a 100-fold reduction of the sample volume from 10 mL to 100 μL. The secondary concentrates were analysed by reverse transcription and polymerase chain reaction, and the sensitivity was shown to be between 0.02-0.2 plaque forming units of enterovirus. This allows the theoretical detection of approximately 1 PFU/L of wastewater. The Tth polymerase was shown to be more effective for the amplification of virus in wastewaters than was Taq polymerase. Overall, the procedure enabled the sensitive detection of rotavirus, hepatitis A, and enterovirus from wastewaters.
Studies evaluating the applicability of utilising the same concentration techniques for the detection of protozoan parasites and viruses in water
Authors: Kfir R. , Hilner C. , du Preez M. , Bateman B.
Published: May 2018

In this study concentration techniques regularly used for viral detection, i.e. flat-bed ultrafiltration and Filterite cartridge filtration, were evaluated for their efficacies in the recovery of protozoan parasites from water. Recovery of cysts was studied using tap water seeded with Giardia muris cysts and compared to methods designed for the detection of protozoan parasites. Recovery of cysts utilizing 1.2µm membrane filters was 11.1% (4.5-23%) compared to 11.6% (2.7-25.5%) with ultrafiltration (pore size 46-50 Å, with a molecular cut off of 50 000 daltons). Comparison of these methods for the isolation of Giardia cysts and Cryptosporidium oocysts from environmental water samples also indicated a similar efficacy. The recovery of cysts from 1001 of seeded samples using a Cuno wynd cartridge filter was 12.2% (1.6-46%) compared to 13.4% (5-24.2%) using a Filterite cartridge filter. Although the results indicated similar recovery efficacies for these two methods, use of Filterite resulted in a more consistent recovery rate. This study also indicated that the use of cartridge filters for the processing of large volume water samples (1001) showed a slightly better recovery efficacy than the flat-bed filtration technique which limits sample volume to about 101.

This study shows that concentration techniques utilised for the isolation of enteric viruses can also be applied for the detection of protozoan parasites from water. This procedure allows for co-analysis of both viruses and protozoan parasites and provides a more rapid and cost-effective evaluation of water quality.
Evaluation of an extraction-precipitation method for recovering hepatitis A virus and poliovirus from hardshell clams (mercenaria mercenaria)
Authors: Alouini Soumaya , Sobsey Mark D.
Published: May 2018

Epidemiological evidence of shellfish mediated transmission of enteric viral diseases and the inability of bacterial indicators to reliably predict viral contamination of shellfish highlight the risks associated with shellfish consumption. This problem suggests the need for direct virological examination of shellfish, and a number of methods have been developed to recover enteroviruses from clams and other bivalve molluscs. These methods have been evaluated primarily for recovery of poliovirus, and there has been little or no testing of their ability to recover hepatitis A virus (HAV). The present study was done to evaluate a new extraction-precipitation method for recovery of both poliovirus and HAV from experimentally contaminated hard clams. In the method 50-gram clam samples are homogenized after supplementing with saline and beef extract and then extracted with an equal volume of fluorocarbon. After centrifugation, viruses in the supernatant are precipitated with 12% polyethylene glycol, resuspended in buffered saline and assayed in cell cultures. From a series of replicate trials using clams seeded with test viruses, this method gave poliovirus and HAV recoveries of about 53 and 22%, respectively. Although the recovery of HAV was lower than that of poliovirus, it was considered adequate for further application. In subsequent studies using clams experimentally contaminated by virus uptake from water, the recovery method detected naturally accumulated HAV and poliovirus in clams. The method evaluated in this study is one of the few documented as capable of detecting HAV as well as enteroviruses in hard clams.
Arcobleu, an integrated surveillance system for chronic and accidental pollution
Authors: Sauzade D. , Hénocque Y. , Carof A. H.
Published: May 2018

An integrated surveillance system for chronic and accidental marine pollution is proposed to improve decision making. This project, called ARCOBLEU, is based on organizing advanced communication and information tools and techniques in a multi-source / multi-user architecture. A Franco-Italian consortium associating private companies and public research institutes has already received the support of the EEC MAST program to carry out the preliminary phase of the system requirement, by using the high Tyrrhenean sea as a pilot zone. Future extension to the Western Mediterranean basin is already planned under the name of MED-ARCOBLEU.
The reactivity and fate of a phenoxyacetic herbicide: 4-chloro-2-methylphenoxy acetic acid (MCPA) in the environment
Authors: Bernardini G. , Bolzacchini E. , Orlandi M. , Presutti C. , Rindone B.
Published: May 2018

MCPA has been purified by crystallization and its purity for phenol and chlorocresol, present as contaminants of the commercial material, was checked by HPLC. The purified MCPA was used in the chemical reactivity with two catalytic systems manganese(III)tetraphenylporphyrinate-iodosylbenzene and bis[salycilideneethylenediiminocobalt(II)]-dioxygen. The reaction products were studied.
Persistent contaminants in dolphins: an indication of chemical pollution in the Mediterranean Sea
Authors: Cardellicchio N.
Published: May 2018

Concentrations of metals (mercury and methylmercury, selenium, cadmium, lead), chlorinated pesticides and polychlorinated byphenyls (PCB) have been determined in tissues and organs of Stenella coeruleoalba dolphins beached along the Adriatic and Ionian coasts of Apulia (Southern Italy). The results obtained confirm that in Mediterranean dolphins the accumulation of contaminants is higher than in similar species living in the Atlantic. Therefore cetaceans can be considered “organisms indicating pollution”. Accumulation is influenced by factors such as diet, age and sex. Reproduction plays a fundamental role in the elimination of toxic compounds in females. Correlation between contamination and death has not been found; however it is clear that pollutants at sub-lethal doses have neuro-toxic effects, increase stress and alter immune defences, leaving the organism at a greater risk from disease.
New type of sludge density meter using microwaves for application in sewage treatment plants
Authors: Yamaguchi Seiji
Published: May 2018

Sludge density is an important index for the control of sewage and sludge treatment processes. A new measuring method for sludge density, the microwave phase difference method, has been tested with a good correlation between density and phase difference. Comparison tests with conventional ultrasonic density meters have shown characteristics that are superior to the flow-through type and equivalent to the defoaming type.

We developed a sludge density meter that uses this method and made long-term field tests on the sludge pipelines in sewage treatment plants. Results demonstrated a good correlation with the values that were obtained by manual analysis, with excellent linearity from low density of less than 1% to high density of about 30%.

This new microwave measurement method is less affected by soil build-up and air bubbles, is able to measure a wide range of densities from low to high, and is capable of continuous measurement. It is a highly reliable measuring method for practical applications.
A sensor for the secondary clarifier based on image analysis
Authors: Grijspeerdt K. , Verstraete W.
Published: May 2018

The outline of a novel sensor for the secondary clarifier based on the combination of in-line sensor principles and image analysis is presented. The sensor consists of a model secondary clarifier of 10 litres from which samples can be taken at different heights, running parallel with the full-scale plant. These samples are examined in an image analysis system, incorporating a flow through cell, a microscope and specific hardware. The measurements that can be obtained with this apparatus are multifarious: a one-dimensional concentration profile (and a fortiori the sludge blanket height) and the morphology and size distribution of the sludge flocs. Results show that it is possible to characterize the settling properties of the sludge automatically. Furthermore, the information is extended by using a mathematical model to describe the concentration profile. Lab-scale tests demonstrate that the information obtained could be uses to optimize the operation of the plant through suitable process control.
Detection of unusual data in online monitoring of wastewater processing
Authors: Kanaya T. , Hirabayashi K. , Fujita I. , Tsumura K.
Published: May 2018

A basic of process control is to understand process conditions with measuring instruments and to operate processes so as to realize target conditions. If input measured values were inaccurate, output of manipulated variables would become improper and, as a result, it would be difficult to bring the process to the desired condition. In the wastewater treatment process, thanks to the latest progress in sensor technology, numerous automatic measuring instruments have been introduced. However, because of adverse environmental conditions peculiar to the wastewater treatment process such as slime-contaminated sensing elements, long-term continuous measurement is rather difficult. We believe such disadvantages in the measurement are making automatic control of the process very difficult to achieve. Under such circumstances, we have developed a detection system for unusual data which automatically checks six items of deviation from upper and lower limit values, rate of change (too much or too little), collating data from similar measuring instruments, etc. based on the measuring data of the last 30 days. With this system, validity of the accumulated data is being checked using measuring data. Accordingly, it enables us to deal with characteristics of measuring instruments, situations of wastewater treatment plants, seasonal changes, etc. automatically. In this report, automatic methods to establish judgement criteria, structure of this detection system and logic of detection of unusual data are introduced. Furthermore, test results with the data collected from actual wastewater treatment plants are covered.
Six years of practical experience with the operation of on-line analysers
Authors: Londong J. , Wachtl P.
Published: May 2018

The Wupperverband operates 14 sewage treatment plants in the catchment area of the Wupper river.

New treatment plants, which were designed for extended nutrient removal, have been equipped with on-line analysers. To find the lay-out data, to control operation and as a support for the start-up phases of new treatment plants, a mobile container for on-line analysis of COD, BOD, NH4 and NO3 is in use.

Several types of analysers were tested with different types of sewage and at different sampling points (influent, effluent primary sedimentation, effluent denitrification, effluent nitrification and final effluent). This enables us to compare and to assess the tested machines.

As a result of these comparisons and for operational reasons the photometric principle was chosen for further application. Adequate maintenance with trained staff provided, especially of sampling preparation units, all tested photometric analysers could be used for control and automation purposes because of their reliable measuring values.
Strategies for handling of on-line information for optimising nutrient removal
Authors: Nielsen M. K. , Önnerth T. B.
Published: May 2018

Modern on-line measuring has given many new pieces of information which can reveal so far unknown details about load and process behaviour. This new information is primarily used for control optimisation purposes so that all available unused reserves in the plants during normal operation are used for improving the effluent quality and reducing operation costs. Secondly, the new on-line measurements can also be utilised for identifying the process relations as they are described in: a) software sensors, b) load characterisation and c) capacity of the actual plant.

Because of the 100 times more detailed information we now get from full-scale plant operation, more fundamental development and research can be carried out based on experiments performed directly on full-scale plants and evaluations of the on-line response to identify the model structure and constant dynamics at full scale. In this way it is possible to develop new processes significantly more quickly than before the on-line information was available.

To derive full profit from these improvements the following requirements must be met.

a) Measurement. Before identifying the process design constants it is necessary to compensate for the load applied on the full-scale system. This detailed evaluation is often so tedious that it normally has to be performed on an off-line basis, while the data from on-line measurements are brushed and used for on-line control, consequently the new kind of tools are needed in information handling.

b) The necessary excitations of the processes are always available during alternating operation. A condition for efficient control is controllability of the system; also in this respect the alternating system offers possibilities far more powerful than continuous systems.

c) Third, it is necessary to develop models and strategies which make the new knowledge and control possibilities operational.

The identified models, which are continuously updated, can be used for operational improvements which today give an excellent payback time for investment in on-line measurement and control systems. This is documented by introducing alternating operation which ensures the necessary information richness at plants with capacities down to below 20,000 PE.

This paper discusses the key points in the recommended approach to and structure of the information handling. The efficiency is demonstrated by introducing alternating operation on a conventional recirculating plant.
Advanced computer control based on real and software sensors
Authors: Önnerth T. B. , Nielsen M. K. , Stamer C.
Published: May 2018

The introduction of state-of-the-art on-line meters is the first step towards achieving more intelligent operation of wastewater treatment plants as the directly involved parameters are known. The use of these on-line measurements is dependent on the reliability of the data, which is the control system STAR, Superior Tuning and Reporting, is secured by DQC, Data Quality Control. With reliable measurements combined with selected operational data, it is possible to identify process relations and implement on-line control strategies such as those performed by STAR today in oxygen set point control, intermittent aeration control and recirculation control.

Some of the STAR control functions are based on a certain kind of calculations described as software sensors, where information is achieved from qualified data and statistical data handling. Software sensors give an improved basis for on-line control strategies. These model-based “sensors” are available in an advanced process control systems such as STAR.

The results compiled at the Sydkysten WWTP show that the introduction of STAR control affords larger economies than expected. Today, the amount of energy consumed at the plant has been reduced by 30% and the dosing of carbon for denitrification by 100%. The economies achieved run into approx. DKK 470,000 per year and the new expense relating to the operation and maintenance of meters is, by comparison, DKK 55,000.
Stormnet: a connectionist model for dynamic management of wastewater treatment plants during storm events
Authors: Gong N. , Ding X. , Denoeux T. , Bertrand-Krajewski J.-L. , Clément M.
Published: May 2018

Models for solid transport in sewers during storm events are increasingly used. An important application of these models is the management of treatment plants during storm events so as to improve the quality of receiving waters. However, a major difficulty that prevents more general use of these tools is their calibration, which requires field data, accurate information about catchments and sewers, and a specific methodology. For that reason, a connectionist model called STORMNET has been designed to reproduce and replace usual conceptual and deterministic models. This model requires fewer data, can be automatically calibrated, and is comparatively simple. It is composed of two recurrent neural networks for the simulation of hydrographs and pollutographs of suspended solids, respectively. In this paper, we present an updated version of STORMNET designed for optimal management of wastewater treatment plants during storm events. This model has been validated using both model and real data. The results show the efficiency of STORMNET as a computational tool for simulating stormwater pollution.
Preliminary uncertainty analysis – a prerequisite for assessing the predictive uncertainty of hydrologic models
Authors: Lei Jian Hua , Schilling Wolfgang
Published: May 2018

Physically-based urban rainfall-runoff models are mostly applied without parameter calibration. Given some preliminary estimates of the uncertainty of the model parameters the associated model output uncertainty can be calculated. Monte-Carlo simulation followed by multi-linear regression is used for this analysis. The calculated model output uncertainty can be compared to the uncertainty estimated by comparing model output and observed data. Based on this comparison systematic or spurious errors can be detected in the observation data, the validity of the model structure can be confirmed, and the most sensitive parameters can be identified. If the calculated model output uncertainty is unacceptably large the most sensitive parameters should be calibrated to reduce the uncertainty. Observation data for which systematic and/or spurious errors have been detected should be discarded from the calibration data. This procedure is referred to as preliminary uncertainty analysis; it is illustrated with an example. The HYSTEM program is applied to predict the runoff volume from an experimental catchment with a total area of 68 ha and an impervious area of 20 ha. Based on the preliminary uncertainty analysis, for 7 of 10 events the measured runoff volume is within the calculated uncertainty range, i.e. less than or equal to the calculated model predictive uncertainty. The remaining 3 events include most likely systematic or spurious errors in the observation data (either in the rainfall or the runoff measurements). These events are then discarded from further analysis. After calibrating the model the predictive uncertainty of the model is estimated.
Identification of Biodegradation models under model and data uncertainty
Authors: Vanrolleghem Peter A. , Keesman Karel J.
Published: May 2018

In this paper a number of nonlinear parameter estimation methods are evaluated with respect to their ability to identify biodegradation models from “real-world” data. Important aspects are then the sensitivity to local minima, rate of convergence, required prior knowledge and direct or indirect availability of parameter estimates uncertainty. Furthermore, it is important whether a method is robust against invalid assumptions. In addition to the final parameter values, covariance and correlation matrices, confidence intervals and residual sequences are presented to obtain information about the validity of the models and noise assumptions. Finally, recommendations on the method's applicability range are provided.
Effect of input uncertainties upon scenario predictions for the river vecht
Authors: Aalderink R. H. , Zoeteman A. , Jovin R.
Published: May 2018

Within the restoration plan for the river Vecht, the linked flow-water quality model DUFLOW has been applied to describe the behaviour of heavy metals. The model has been used to predict the effects of a number of scenarios for improvement of water quality. In this paper an analysis of the input uncertainty and the effect upon the resulting uncertainty in the output is presented. Both the influence of parameter uncertainty and the uncertainty in the other input variables as: boundary conditions, loading from point and non-point sources, and initial conditions, has been studied. From reported ranges in literature an estimate of the parameter uncertainty has been made. The uncertainty within the other input variables has been assessed from available data. Through Monte Carlo simulation, using Latin Hypercube sampling the resulting uncertainty in the model predictions has been determined. From the uncertainty analysis it appeared that it was not possible to discriminate between the predicted impacts of some of the scenarios. Both the uncertainty in the parameters and in the loading of the system contributed to the overall model uncertainty, although their relative contribution differed going from south to north in the system.
Pollution risk management for resource protection
Authors: Norton Roger L. , Oakes David B. , Cole John A.
Published: May 2018

This paper deals with the management of the often brief pollution incident which gives rise to a sudden emergency. There are two key aspects to pollution risk management: the identification and minimisation of potential and actual risks (pro-active management), and planning how to deal with such incidents as do occur (reactive management). Pro-active management involves the identification of potential pollutants within a catchment and assessing what can be done to minimise the risks at source. Reactive management deals with the actions necessary which will depend on the severity of the incident, and covers both administrative procedures and practical issues. These concepts of pollution risk preparedness are described, and illustrated with a number of case studies.