bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of phase separation in anaerobic digestion on different substrates
Authors: Jeyaseelan S. , Matsuo T.
Published: May 2018

Treatment characteristics of two different substrates were investigated by two-phase anaerobic digestion at 20 °C. One substrate contained 87 percent carbohydrates and proteins and the other 94 percent carbohydrates and lipids. The anaerobic system consisted of a completely mixed reactor for hydrolysis and acidogenesis reactions, and an upflow filter for methanogeneous conversions. The experiments showed that the best phase separation occurs with 4 to 8 hours of detention times within the acid reactor. A single anaerobic system with upflow anaerobic filter alone for the same total detention times at the same substrate concentrations was operated for comparison. The results proved that two-phase digestion systems have higher digestion efficiencies than corresponding single-phase digestion systems. For substrates with more lipids the digestion efficiencies were very much greater.
A study of a modified process for the intermittent cycle extended aeration system
Authors: Ouyang C. F. , Juan C. T.
Published: May 2018

This study applies the single continuous-inflow batch system to treat domestic wastewater directly by the procedures of continuous-inflow, intermittent aeration, and intermittent-outflow. In four runs, varied influent rate, organic loading, cycles per day and the time of aeration/non-aeration phase per cycle used to determine the treatment characteristics of the system. In the experimental results, the system showed good efficiency of BOD, nitrogen and phosphorus removal simultaneously under the conditions of appropriate operation parameters. The developed vertical up-downward decanter and baffle with holes are modified from the conventional single batch system and can minimize the short-circuit as the inflow is continuous and make the effluent qualities stable.
Biological and nutritional approach to the environmental impact of trout culture in Portugal
Authors: Rodrigues A. M. P.
Published: May 2018

In order to address the problems of pollution from commercial farms, the bioavailability of nutrients in commercial feeds available in Portugal was evaluated in three size (40 g, 100 g and 180 g) groups of rainbow trout (Oncorhynchus mykiss) over a one year period and under natural production conditions. The principal factors influencing apparent digestibility values were diet quality, temperature and dissolved oxygen. Most probably suspended solids also affected digestibility especially during the summer months. The apparent digestibilities of crude protein, organic matter and dry matter were strongly inversely correlated with dietary fibre level in the 3 size groups of farmed trout. In addition, significant positive correlations were obtained between lipid level in commercial feeds and the organic matter digestibility coefficients. A significant correlation was also obtained between all apparent digestibility coefficients and the feed protein level for all size groups of fish studied in the field. The need for, and importance of, digestibility studies is demonstrated through estimates of nutrient flow and waste production in two different situations illustrating the effect of dietary quality.
A multi-disciplinary Danish research programme on rainbow trout (Oncorhynchus mykiss) farming
Authors: Berg P. , Eggum B. O. , Møller S. H. , Holm L.-E. , Jørgensen P. E. V. , Olesen N. J. , Buchmann K. , Larsen J. L. , Dalsgaard I. , Mellergaard S. , From J. , Frier J.-O. , McLean E. , Hørlyck V. , Graver C. , Kristensen T. P. , Birk E. , Bovbjerg P.
Published: May 2018

A new research programme involving eight Danish institutions is described. The programme started in 1993 and is expected to run for 5 years. The primary objective of the research initiative is to exploit and integrate the knowledge of several institutions and disciplines for the benefit of the production of rainbow trout. The programme includes several projects with aspects of disease prevention, genetics, and nutrition. In most of the projects, the work has been divided into stages of 2 and 3 years, respectively. During a 2 year period, production, management, and health status are recorded at the participating fish farms, and all data are organized in a database. Diseases cause major problems in rainbow trout production, therefore a great deal of the effort in this programme deals with diseases caused by vira, bacteria and parasites. On the basis of the database, epidemiological examinations are carried out as well as investigations of the possibilities of preventive measures and cost-benefit analyses.

In the genetic studies, polymorphic genetic markers will be developed and used for analysis of the genetic structure of selected fish stocks. Microsatellites will be developed and introduced in the study. Primarily genetic differences between lines/strains and their crossings will be estimated with the purpose of describing the genetic level and the importance of additive and non-additive genetic effects. In the nutritional area the product quality and pollution questions will be in focus.
A chemical and sensory study of odour compounds in the Athabasca River, Alberta, Canada
Authors: Kenefick S. L. , Brownlee B. G. , Perley T. R. , Hrudey S. E.
Published: May 2018

As of early 1993, the Athabasca River received effluent from one bleached kraft pulp mill (Mill A), three chemithermomechanical pulp and paper mills, one oil sands extraction and upgrading plant and a number of municipal effluents. In the latter half of 1993 a second bleached kraft pulp mill (Mill B) began operation midway along the river. An investigation was carried out to characterize the odours in the river water using both chemical and sensory methods, in a pre- and post-operational study of the second bleached kraft mill. Both surveys were carried out under ice during low flow conditions. Samples were analysed by gas chromatography-mass spectrometry after extraction using a closed-loop stripping apparatus (CLSA). In addition, sensory analysis by flavour profile panel and olfactory gas chromatography of the CLSA extracts were performed. In 1993 all analytical methods confirmed that compounds characteristic of bleached kraft mill effluent were detectable for more than 950 km downstream from Mill A and that this effluent was the major source of odour to the Athabasca River. Chemical and sensory results for 1994 samples (collected after Mill B began operation) indicated a decrease in the impact of Mill A compared with the 1993 survey. The Mill B effluent had distinctive odour but its impact on the river was difficult to detect due to dilution and background odour from the Mill A effluent.
High rate settler in biological system for oil and soap wastewater treatment
Authors: Abou-Elela S. I. , Ashmawy A. , Aly H. I. , Ahmed H. M.
Published: May 2018

Wastewater from an oil and soap company provided the material of this study. The company discharges 31,000 m3/d of untreated wastewater into the Nile River. The wastewater was highly contaminated with organic and inorganic pollutants. An end-of-pipe treatment scheme was devised of dissolved air flotation with/without alum followed by biological degradation. The biological unit was compact and comprised an aeration tank based on a completely mixed activated sludge process followed by a high rate settler. The unit was operated at two organic loads, namely 1.44 and 2.88 kg BOD5/m3/d. The results obtained showed that this scheme of treatment produced a high quality effluent suitable for disposal into surface water or reuse. Also, the high rate settler acted as a biological reactor as well as a settler for finely divided organic matter.
Wastewater characteristics in Palestine
Authors: Nashashibi M. , van Duijl L. A.
Published: May 2018

Wastewater treatment plants in Palestine (West Bank and Gaza Strip) have been designed upon assumptions of wastewater characteristics and amount of flow, because no data were available at all. This study is focused on the collection and measurement of wastewater quantity and quality, which will be used as a basis for formulating a strategic plan for wastewater treatment in Palestine. In view of the limited water resources, reclaimed wastewater will be used for agriculture, which, at present, is done at a very limited scale.

The infrastructure in Palestine used to be a neglected issue, particularly with regard to sewerage. Blocked pipes and flooded manholes are daily events especially in Gaza Strip. All existing treatment plants are heavily overloaded. Groundwater resources in Gaza Strip become more and more polluted with nitrate concentrations exceeding 100 mg NO3-N/l resulting from seepage from cesspits and effluent discharges into wadis.

Due to scarcity of water, domestic water consumption is very low, which leads to highly concentrated wastewater similar to industrial one. In one city in the West Bank, the COD reached a value of 3,670 mg/l, although all the water reaching the outfall is of domestic type.
The source of bromophenols in some species of Australian ocean fish
Authors: Whitfield F. B. , Helidoniotis F. , Svoronos D. , Shaw K. J. , Ford G. L.
Published: May 2018

The carcass and gut contents of 10 species of fish caught along the eastern coast of Australia were analysed by gas chromatography-multiple ion detection-mass spectrometry for a range of bromophenols including 2- and 4-bromophenol, 2,4- and 2,6-dibromophenol and 2,4,6-tribromophenol. These bromophenols, the cause of iodoform-like off-flavours in seafoods, were found in eight of the above species; the largest total concentrations of bromophenols occurred in the commercially important species Nemadactylus douglasii (40 ng/g). The concentrations of bromophenols in another three species Branchiostegus wardi, Rhabdosargus sarba, and Girella tricuspidata, were found to exceed 10 ng/g while in a further four species their concentrations varied between 3 and 8 ng/g. However, these compounds were not identified in the remaining two species at a detection limit of 0.05 ng/g. The variations among fish diets suggest that the bromophenol content of individual fish can be explained by the relative contribution of benthic organisms and marine algae to the fish diet. Bromophenols were found in all of the benthic carnivores and diverse omnivores examined but were not detected in pelagic carnivorous fish.
Wastewater treatment and reuse for aquaculture
Authors: El-Gohary F. , El-Hawarry S. , Badr S. , Rashed Y.
Published: May 2018

A continuous laboratory scale model, simulating an oxidation pond system has been used to investigate the treatability of municipal wastewater and to evaluate the treated effluent for aquaculture. While the detention period was kept constant at 25 days, the organic loading rate fed to the system changed with changes in the BOD5 of the raw sewage and varied from 15.7 to 58.3 with an average value of 34.1 kg BOD5/ha/day.

Monitoring of the system indicated remarkable improvement in the water quality of the treated effluent. BOD5 was around 26 mg O2/l. Average residual values of COD, suspended solids and phosphorus were 154, 65 and 3.2 mg/l respectively. A reduction up to 99.99% in coliform bacteria population has been recorded. However, residual values were still high.

Tilapia fish grew healthily during the study period. Daily growth rate was 1.43% of the body mass. The productivity was 7.15 kg/ha/day. The corresponding extrapolated yield was 26.09 t/ha/yr which is considered to be a high yield as compared to published information.
The effects of copper sulfate on geosmin biosynthesis by streptomyces tendae, streptomyces albidoflavus, and penicillium expansum
Authors: Dionigi Christopher P.
Published: May 2018

Geosmin is produced by several phototrophic and heterotrophic taxa. This secondary metabolite can impart an earthy taste and odor to water resources. To reduce algal populations and associated biosynthesis of geosmin, copper sulfate and other copper-containing algicides are often applied to aquatic systems. Cultures of the bacterium Streptomyces tendae and the fungus Penicillium expansum grown on increasing concentrations of copper sulfate accumulated more biomass than untreated controls, indicating that these heterotrophic cultures were not markedly susceptible to this algicide. Cultures of Streptomyces albidoflavus treated with increasing concentrations of copper sulfate accumulated less biomass than untreated controls. However, copper-treated mycelium of each taxa investigated contained greater concentrations of geosmin than untreated controls. In addition, there was not a significant interaction between in the amount of biomass or geosmin accumulated by cells exposed to 0 and 0.5 mg l−1 copper sulfate over increasing dosages of zinc sulfate. If field populations exhibit similar responses, application of copper sulfate to aquatic systems may contribute to geosmin biosynthesis by certain taxa.
Elimination of terpenoid odorous compounds by slow sand and river bank filtration of the Ruhr River, Germany
Authors: Jüttner F.
Published: May 2018

The elimination of odorous compounds by river bank and slow sand filtration was studied at the Ruhr River in Germany. The aquifer of the river bank filtration was anoxic and exhibited intense dissimilatory nitrate reduction; the aquifer of the slow sand filter was oxic. Polar monoterpenes, such as linalool, menthol, isobornyl acetate, lipoxygenase products (oct-1-en-3-ol) and geosmin exhibited a much higher percentage elimination than monoterpene hydrocarbons and other lipophilic compounds (dimethyldisulphide, aliphatic and aromatic hydrocarbons). The efficiency of river bank filtration was slightly better than that of slow sand filtration. The schmutzdecke and upper layers of the slow sand filters were responsible for most of the removal of VOC. The deeper layers exhibited only small effects.
Biological removal of algae in an integrated pond system
Authors: Meiring P. G. J. , Oellermann R. A.
Published: May 2018

A system of oxidation ponds in series with a biological trickling filter is described. It was known that this arrangement was incapable of reducing effectively the levels of algae present in the pond liquid even though nitrification was effected because of autotrophic conditions prevailing in the trickling filters. This very low trophic level explained the lack of adsorptive capacity present.

By shortcircuiting less than 10 percent of the effluent from a fully loaded primary facultative oxidation pond to the trickling filter, the autotrophuc nature or the film in the trickling filter was sufficiently shifted towards a heterotrophic state that had sufficient adsorptive capacity to retain the majority of the algae.

It is concluded that the algae, although being absorbed, stay alive on the film and do not contribute significantly to the carbonaceous load on the trickling filter. Further more the algae, although secluded from all sunlight, actually partake in the purification process, producing an effluent which, unlike a normal humus tank effluent, is surprisingly sparkling clear. This significant observation appears to be in line with laboratory findings by others who, when they artificially immobilised certain species of algae and passed water over them, concluded that the algae retained the potential to remove certain compounds from the water. Conglomerates of biologically flocculated dark-green algae are scoured off the film (or sloughed off as part of the film) and, having been photosynthetically inactive for some days, tend not to float, but settle very rapidly.

A very significantly aspect of this development is the great potential it has for practical application in developing countries. The algae sloughed off the media are easily thickened and available for ultimate recovery from the water phase without the addition of chemicals.
Strategies in agroindustrial wastewater treatment
Authors: Sendic M. Viñas
Published: May 2018

In this paper, the wastewater treatments of the three most significant agroindustries in Uruguay, slaughterhouse, woolscouring and tannery, are described. Different strategies are used depending on: type of industry, localization, economical possibilities, innovative disposition of management officers. Although more work must be done to improve with “reasonable” costs the wastewater treatments of these industries, actual results are presented.
Significance of biofilm activity in facultative pond design and performance
Authors: Polprasert C. , Agarwalla B. K.
Published: May 2018

Facultative ponds have found wide application in wastewater treatment as an economical systemwhere land area is available at reasonable cost. Different approaches are available in the literature for the design of facultative ponds. Most research have dealt with only suspended biomass and considered it as the major form of biomass responsible for substrate removal. However, the side walls and bottom of the facultative pond can provide support for the growth of attached (biofilm) biomass which also aids in the degradation of organic matters (substrate). This study demonstrates the significance of biofilm biomass growing on the side walls and bottom of these ponds to substrate utilization. A model for substrate utilization in facultative ponds is proposed which encompasses first-order reactions of both suspended and biofilm biomass. The biofilm activity is described with a diffusion type model, while the dispersed flow model is used for the pond hydraulics to include a wide range of pond dimensions and operating conditions. The proposed model, validated with observed data of two full-scale facultative ponds located in Bangkok, Thailand, and in New Mexico, U.S.A., was able to predict effluent BOD5 concentrations of these two ponds reasonably well.
Occurrence of Giardia sp. cysts during a wastewater treatment by a stabilization pond in the South of France
Authors: Wiandt S. , Baleux B. , Casellas C. , Bontoux J.
Published: May 2018

This study was conducted to determine Giardia sp. cysts concentration in wastewater influents and effluents of a stabilization pond system located in Mèze (03°35′06″E, 43°25′10″N), South of France.

In raw sewage mean concentrations ranging from 0.23-25.103 cysts 1-1 were found from February 92 to July 93.

Prior to November 92, large volume filtration combined with brightfield microscopy served as the method for cyst recovery and detection in pond effluents. From November 92, the detection of Giardia sp. cysts was performed by an indirect immunofluorescent antibody test.

No cysts could be detected in the final effluents during summer 92 by brightfield microscopy, whereas cysts were recovered in effluents from the first basin. Cysts were detected in final effluents during wintertime by the fluorescent antibody-technique (0.1 to 2.5 cysts 1-1). However, no cysts were detected during spring/summer 93 in final effluents.

We conclude that alum coagulation in conjunction with immunofluorescent antibody techniques for the concentration and detection of Giardia sp. in stabilization pond effluents increases the recovery efficiency and identification of waterborne cysts.

The results of this study indicate a good removal efficiency of cysts in a stabilization pond during spring/summertime but a potential risk of cyst discharge during wintertime.
Evaluation of serratia marcescens bacteriophage as a tracer and a model for virus removal in waste stabilisation ponds
Authors: Frederick G. L. , Lloyd B. J.
Published: May 2018

The use of Serratia marcescens bacteriophage as a tracer and a model for virus removal in the Cayman Islands' waste stabilisation ponds was investigated. A series of bench-scale experiments was designed and carried out to determine the survival of Serratia marcescens bacteriophage in the various stages of a waste stabilisation pond system. The study investigated whether the physico-chemical conditions expected in facultative and maturation ponds precluded the use of phage tracers. By the end of the 6th day, phage in filtered and unfiltered raw sewage and facultative pond samples, in normal sunlight, was undetectable. In the maturation pond samples, in normal sunlight, phage was undetectable by the 4th day. There was a high correlation between increased phage reduction and increased pH levels. The phage was still detectable on day 13 in maturation pond experiments kept in the dark. Therefore the study concluded that Serratia marcescens bacteriophage may be useful as a tracer in ponds with retention times up to 14 days provided average pH at the outlet is <9.0.
Design and control of flotation thickeners
Authors: Bratby J. R. , Ambrose W. A.
Published: May 2018

Process variables influencing clarification and thickening by dissolved air flotation are summarized. Operational adjustments to full-scale thickeners are usually limited to the speed and periodicity of the float scrapers which, in turn, directly influence the effective drainage time of liquid from the floating sludge mass. Expressions are derived which relate float solids concentration and total float depth to the effective drainage time. Design and operation charts are derived from the equations. Results obtained from the City of Philadelphia Northeast WWTP are used to demonstrate the validity of the derived expressions. The enhanced thickening characteristics obtained when water treatment plant sludge was discharged to the WWTP is demonstrated. Polymer addition had only a slight beneficial effect. Use of the charts for operational control is demonstrated by means of an example.
Quo vadis - sustainability?
Authors: Tyson J. M.
Published: May 2018

There is a developing concern that the world water resource will prove to be inadequate to meet the ever-increasing demands by humankind. An integrated river basin management approach is essential for land and water use planning due to the complexity of land/water interactions.

This paper provides a selective overview of some of the issues affecting sustainability in river basin management. These include the need to: develop methodologies for integrated river basin management which include land-use management and planning; improve the volume and accuracy of national and global assessment of water resources; develop, promulgate and implement waste minimisation and recovery techniques, preferably pollution prevention; develop low-tech, low cost treatment options; increase application of use-related receiving water standards; develop and apply economic evaluation tools to both environmental costs and benefits; and inform, educate and train professionals and the public.

Any solution arrived at must be acceptable to the local community; two-way communication is vital to the success of a project, which may well require changes in the behaviour of the community served.
Water quality objectives: a tool to ensure environmental protection and wise expenditure
Authors: Matthews P. J.
Published: May 2018

The paper describes the relationship between politics, environment and economics as a background to the demands for managing environmental water and effluent qualities. The alternatives to meet these demands environmental protection and cost to be assessed together. Quality targets are set for environmental waters which ensure that the agreed uses of the water are protected. These targets can then be related to discharge standards. This provides a framework for priority planning and investment which separates the politics from science. The principles are exemplified by the practical experience of Anglian Water, an English Water Company (and the predecessor authority).
Integrated catchment management: is it wishful thinking or can it succeed?
Authors: van Zyl F. C.
Published: May 2018

The need for better and improved water resources management has been echoed time and again worldwide. In South Africa, where water has been identified as a scarce resource and a limiting factor for development, the situation is even more critical. To address this problem, management of water on an integrated catchment basis has been applied to various catchments in the country. The development and implementation of this approach offered managers unique learning experiences. They had to content with complex water resource problems as well as with economic and political difficulties. On the one hand it was a very exciting and challenging experience, on the other hand success was limited and in many cases the results were disappointing.

In this paper, the approaches adopted and the experiences gained in the execution of more than twenty major catchment management projects, as well as various issues impacting on the outcome of the projects, are highlighted. It is important to realise that this approachs is in a development phase and still requires time and energy to become a meaningful management practice.
Integrated research into estuarine management
Authors: Slinger J. H. , Breen C. M.
Published: May 2018

Estuaries are under increasing pressure owing to agricultural, urban and industrial developments in their catchments and their status as favoured sites for coastal development and recreation. Effective research on South Africa estuaries requires the synthesis of available scientific knowledge to efficiently address management concerns and so ensure the sustainable utilisation of estuaries. The approach of the Consortium for Estuarine Research and Management to these problems and the results of a co-ordinated research programme on decision support for the management and conservation of estuarine systems are described in this paper. While the importance and current status of South African estuaries are considered, attention is devoted primarily to the development of an integrated modelling approach to the freshwater requirements of estuaries. In particular, the application of a linked system of five models to a case study, the Great Brak Estuary is described and the role of prediction in promoting wise decision making for estuaries is treated.
Detection of poliovirus by cell culture and by PCR after UV disinfection
Authors: Maier A. , Tougianidou D. , Wiedenmann A. , Botzenhart K.
Published: May 2018

The polymerase chain reaction (PCR) is used for the detection of microorganisms in water, but it is known that one does not detect only viable microorganisms by PCR. The following results show the detection of poliovirus on a cell culture assay and by PCR after inactivation by UV irradiation. The virus was irradiated with a low pressure mercury lamp with times up to 4000 seconds (=3980 J/m2). A 4 log inactivation of the virus was complete after 300 seconds (=294 J/m2) as shown by the cell culture assay. The viral RNA was detectable by PCR even at irradiation times of 4000 seconds.
Participatory catchment management — an opportunity for Southern Africa
Authors: Versfeld D. B.
Published: May 2018

South Africa has hundreds of thousands of hectares of heavily populated and badly degraded landscapes. Past attempts at land management have been either through avoidance or the top-down imposition of “betterment” schemes. Participatory methods offer a new opportunity for communities living within these catchments to share their knowledge and to become involved in planning and implementing the management process. This paper discusses the use of Participatory Rural Appraisal (PRA) in a catchment rehabilitation programme in rural KwaZulu/Natal, the lessons learnt and the prospects for wider application.
Effluent disinfection in warm climates with peracetic acid
Authors: Baldry M. G. C. , Cavadore A. , French M. S. , Massa G. , Rodrigues L. M. , Schirch P. F. T. , Threadgold T. L.
Published: May 2018

Laboratory experiments and full-scale trials in Brazil and Italy are reported that show that peracetic acid is a good disinfectant (better than sodium hypochlorite) of sewage in tropical and warm temperate climates. Its demonstrated effectiveness against V. cholerae suggests it should be a significant element in cholera control efforts.
Management of microbial water quality: new perspectives for developing areas
Authors: Steynberg M. C. , Venter S. N. , de Wet C. M. E. , du Plessis G. , Holhs D. , Rodda N. , Kfir R.
Published: May 2018

A case study indicated that the high number of pathogenic micro-organisms in the Rietspruit, South Africa, can impact water uses. Factors contributing to high microbial numbers are high density population with limited services provided per site, sabotage of the sewage reticulation system, lack of money and management skills to provide the essential services and limited integrated development planning for the catchment.

Due to non-steady state conditions in the catchment, the specific use and physical characteristics of the river and the difficulty in determining flow, the usefulness of a steady-state stream water quality model as a management tool is limited. Determining the decay rate of micro-organisms by means of chamber studies, may be a first step to predict microbial water quality. Involving the community in preventing microbial pollution may be a more appropriate tool for microbial water quality management in developing areas.
F-specific bacteriophage as an indicator of human viruses in natural waters and sewage effluents in Northern New Zealand
Authors: Lewis Gillian D.
Published: May 2018

To assess the F-specific bacteriophage as an indicator of pathogenic viruses, a comparative study has been made of the occurrence of F-phage and human enteroviruses in sewage wastes and the marine environment. Although F-phage seemed in several respects to match pathogen behaviour, its low abundance in bathing beach water, uncertainty as to its source and other detection irregularities make its use as an indicator problematical.
Evaluation of indicators for assessment of human and animal faecal pollution of surface run-off
Authors: Jagals P. , Grabow W. O. K. , de Villiers J. C.
Published: May 2018

The value of selected indicators for assessment of faecal pollution, as well as the distinction of faecal pollution of human or animal origin, has been investigated. The following indicators were included: faecal coliform bacteria, faecal streptococci, sorbitol-fermenting bifidobacteria, Rhodococcus coprophilus, somatic and male-specific coliphages, phages of Bacteroides fragilis, and cytopathogenic viruses. Comparative tests were carried out on samples collected from a stream and river exposed to predominantly faecal pollution of domestic animal origin, and the same stream and river after downstream exposure to run-off from a low socio-economic informal settlement with restricted sanitation. Samples were collected from perennial flow during the dry season and from stormwater run-off after thundershowers. Stormwater run-off from the settlement reached faecal coliform counts of up to 4 400 000 per 100 ml, which is equivalent to that of many raw sewage effluents. Faecal pollution was less during the dry season. Sorbitol-fermenting bidifobacteria were identifiable with faecal pollution of human origin, and R coprophilus bacteria with that of animal origin. The ratio of faecal coliforms to faecal streptococci was in the order of 3.5 to 4.7 immediately after exposure to sewage pollution of human origin. In water exposed to faecal pollution predominantly of animal origin, and downstream from pollution of human origin, this ratio varied from 0.8 to 1.7, which indicates that under circumstances the ratio may also distinguish between faecal pollution of human and animal origin. Phages of B fragilis and cytopathogenic viruses were not detected by direct titration in any of the samples, which implies that their application in this situation would require more sensitive techniques. The results show that the run-off from the informal settlement constituted a major source of pollution for a river catchment which downstream is used as a source of water for human consumption, and that faecal pollution of human and animal origin can reliably be distinguished by means of combinations of appropriate indicators.
Use of the polymerase chain reaction for the detection of enteroviruses in river and marine recreational waters
Authors: Wyn-Jones A. P. , Pallin R. , Sellwood J. , Tougianidou D.
Published: May 2018

The polymerase chain reaction (PCR) was used to detect human enteroviruses in river and seawater samples in comparison with cell culture analysis. Extraction of the RNA from the sample was achieved by adsorption to size-fractionated silica in the presence of guanidinium thiocyanate. Good correlation was obtained between the two methods. For most samples it was not found necessary to carry out an initial cell culture passage prior to RT-PCR analysis, and RT-PCR was found to be as sensitive and more rapid than cell culture.
Polymerase chain reaction amplification and typing of rotavirus in environmental samples
Authors: Gajardo R. , Pintó R. M. , Bosch A.
Published: May 2018

A reverse transcription polymerase chain reaction (RT-PCR) assay is described that has been developed for the detection and serotyping of group A rotavirus in stool specimens and concentrated and non-concentrated sewage specimens.
Detection of legionella spp. using a commercially available polymerase chain reaction test
Authors: Fricker E. J. , Fricker C. R.
Published: May 2018

A commercial test kit (the EnviroAmp Legionella Kit) for the detection of legionellas using the polymerase chain reaction is compared with the standard culture methods for water samples. The EnviroAmp kit proved to be rapid and did not require great experience of molecular biological techniques. However as number of samples which tested negative with the standard culture, were positive with the kit; further research is needed to establish whether this due to the detection of dead or viable but non-culturable legionellas.
Recovery of somatic coliphages in shellfish
Authors: Albert M. , Vannesson C. , Schwartzbrod L.
Published: May 2018

A phage recovery technique is described that is shown to be easy to perform and sensitive. It is efficient in detecting somatic coliphages in mussels artificially contaminated, even at very low levels. Good results are also reported for detection and enumeration of naturally occurring coliphages in mussels and cockles from the French Atlantic coast.
Development of a PCR-based method for the detection of enteroviruses and hepatitis a virus in molluscan shellfish and its application to polluted field samples1
Authors: Lees David N. , Henshilwood Kathleen , Butcher Sarah
Published: May 2018

The use of the polymerase chain reaction (PCR) for detection of low levels of enteric viruses in bivalve shellfish is hindered by the presence of potent amplification inhibitors. A procedure previously developed for removing the majority of these amplification inhibitors is applied to the detection of enteroviruses and hepatitis A virus in naturally polluted field samples. Quantification of PCR inhibition showed that PCR sample tolerance ranged from 2 to 4.7g shellfish for highly polluted samples. These results indicate the need for adequate controls for PCR inhibition, particularly for negative samples. Reverse transcription (RT)-PCR results were compared with conventional enterovirus isolation for a range of naturally contaminated shellfish. All enterovirus isolation positive samples were also positive by enterovirus RT-PCR. At one field site shellfish were positive by enterovirus RT-PCR but negative for virus isolation. All shellfish tested were negative for hepatitis A by RT-PCR. The procedure for removal of PCR amplification inhibitors should be equally applicable to the detection of Norwalk and related Small Round Structured Viruses (SRSVs) in shellfish.
Pollution of the Meditterranean Sea
Authors: Gabrielides G. P.
Published: May 2018

The Mediterranean States adopted an action plan for the protection of their common sea from pollution as early as 1975. This comprehensive action plan is not limited to monitoring of marine pollution but includes all aspects relevant to environment and development. It is coordinated from the Athens-based Centre but regional offices also exist being responsible for the implementation of specific programmes. The scientific and technical component of the action plan (the MED POL programme) was the first one to be initiated involving more than 100 Mediterranean research and monitoring institutions. Selected results of the monitoring programme are presented shortly. The following parameters are dealt with: mercury, cadmium, copper and zinc, organohalogen compounds, organotins, organophosphorus compounds, herbicides and fungicides as well as synthetic persistent materials. The results have shown that pollution in the Mediterranean sea is limited to coastal areas where the sources, such as industries and population centres, are found. The north-western Mediterranean has shown higher pollutant concentrations either because of natural sources (case of mercury) or because of the industrial development of the region.
Effluent re-use in a tourist resort - larnaca sewage treatment and irrigation project - cyprus
Authors: Mill G. A. , Theophilou J. A.
Published: May 2018

Designs for sewerage, sewage treatment and effluent disposal prepared in the 1980's, included for marine disposal of secondary treated and disinfected effluent via a 1.5 km long sea outfall. A reappraisal of the scheme in 1990 reviewed alternative options with a view to reducing costs and utilising effluent.

An economic comparison showed that effluent storage and irrigation was an attractive alternative to marine disposal.

A scheme was designed whereby all effluent will be given secondary treatment, stored in reservoirs until required for irrigation, withdrawn through sand filters, disinfected and pumped to an irrigation distribution system serving public amenity areas throughout Larnaca, including parks, gardens, road verges and hotel areas. A sea outfall will not be provided.

The advantages of the scheme are conservation of water, improvement to the environment and prevention of marine pollution at a reduction in cost compared to the originally proposed scheme.
Performance of a two stage plastic media trickling filter in Greece
Authors: Guitonas A. , Alexiou G.
Published: May 2018

This paper presents the final results of a two years research programme, which has been funded by the Commission of European Union (STEP programme). The main objective was the study of sewage treatment for a wide range of ambient temperatures, in order to produce effluents of adequate quality to meet EU standards. Hydraulic and quality models of the processes involved, with various types of filter media, have been produced both for full scale and pilot size plants. The group from Aristotle University of Thessaloniki (A.U.T.), undertook the study of the reduction of the organic and nitrogen loading, under the influence of the very high sewage temperatures experienced during the prolonged summer period. Hydraulic Loading Rate (HLR) was constant (0.40 m/h) while the Organic Loading Rate (OLR) varied between 0.35 - 0.60 kg BOD/m3.d. Nitrogen loading rate was high with a mean period value of 150g N/m3.d. Our pilot has shown a treatment stability at organic loading reduction. Nitrification was never stopped completely, even at the lowest winter temperatures. Nitrogen level was within the EU standards for sensitive areas at the critical summer months. Phosphorus reduction was low only as result of sedimentation, therefore further treatment is required.
Application of a three dimensional model for the prediction of pollutant dispersion in Cyprus coastal waters
Authors: Glekas I. P.
Published: May 2018

A recently developed numerical model for environmental flows has been applied to simulate the water circulation and pollutant dispersion in a confined coastal system in Cyprus. The model is based on the numerical solution of the time averaged Navier-Stokes equations, written in their contravariant strong conservation form, in a generalised non-orthogonal coordinate system. The model predictions are verified compared with experimental data incorporating radioactive tracer injection at the surface of the sea, then the model is applied to predict the dispersion of waste from the outfall pipe of a sewage treatment plant. The predicted results agree favourably with the measurements, demonstrating the code's validity, flexibility and economy for predicting accurately flows in three-dimensional complex sea bed terrain basins. The utilisation of such a model can be an advantageous alternative to the expensive and time consuming experimental field work, enabling the study of the plume dispersion under different discharge and hydrological prevailing conditions.
Long term investment planning for coastal pollution control infrastructure
Authors: Ostojic-Skomrlj N. , Margeta J.
Published: May 2018

The construction of sewerage systems, treatment plants and submarine outfalls designed for the development of coastal urban areas usually represents a long-lasting and significant investment with the aim of improving environmental conditions of the coastal sea water. The investors must have answers to the following questions before starting any activities: how environmental conditions of the coastal sea can be improved with a limited budget and what is the optimal timing of investment regarding the final concept of the infrastructure for pollution control? Providing answers to these questions is neither an easy nor simple task. Consequently, it is necessary to apply system engineering procedures and adequate optimization techniques. This paper deals with the policy of planning the pollution control infrastructure in the Kastela Bay region.
Denitrification kinetics in an activated sludge system
Authors: Roš M.
Published: May 2018

For all water bodies especially for sea, lakes, and ground waters it is very important that nutrient pollution is the least possible (minimal). From municipal and industrial waste waters where considerable amount of nutrients is expected it is possible to remove nutrients with biological treatment. The first step is usually aerobic activated sludge treatment and the second step is combined anaerobic-anoxic-aerobic step in different combinations. A very effective process for nitrogen removal is anoxic activated sludge system. It is very important that in the first aerobic step complete nitrification is achieved.

In our laboratory denitrification kinetics was studied. The objective of this study was determination of denitrification velocity and attendance of different parallel phenomena such as nitrite, disappearance of nitrate and nitrite, sulphide formation, etc.

Denitrification process was studied in two systems, in closed system (such as in closed reactors for denitrification) and in open systems (such as in open denitrification tanks). We found out that denitrification rate in closed systems was from about 8 to 52 mg/l.h and was dependent on activated sludge type, sludge concentration, and temperature of the system. In open system (such as in an anoxic aeration tank) the rate of denitrification was lower than in closed system; it was from 4 to 15 mg/l.h dependent on activated sludge type, sludge concentration, and temperature of the system. Experiments were carried out in the range of temperature from 20° to 30°C.
The potential of off-gas analyses for monitoring wastewater treatment plants
Authors: Hellinga C. , Vanrolleghem P. , van Loosdrecht M. C. M. , Heijnen J. J.
Published: May 2018

Continuous CO2 and O2 measurements in the exhaust gas of wastewater treatment plants have been simulated to study their significance for fast process monitoring. More specifically, the question was raised whether the ratio of the carbon dioxide production rate to the oxygen consumption rate (the RQ value) can be used to distinguish C-oxidation from N-removal (nitrification or combined nitrification-denitrification). Although the oxygen uptake rate and carbon dioxide production rate by the micro-organisms are indicative indeed, these rates can not very well be monitored in the gas phase mainly due to the additional CO2 production accompanying alkalinity consumption. Only large changes in nitrification activity can be monitored this way. The RQ is however a strong measure for the COD/TOC ratio of the converted waste. Combination of RQ measurements with TOC measurements can therefore probably replace laborious COD measurements. In plants with combined C-removal and nitrification, the difference in in- and effluent alkalinity is a measure for nitrification. If NH3-removal is determined, the biomass production rate can be calculated from the gas flow rate in combination with the exhaust CO2 and O2 measurements.
N and P on-line meters: requirements, maintenance and stability
Authors: Thomsen Henrik A. , Kisbye Kenneth
Published: May 2018

State-of-the-art on-line meters for determination of ammonium, nitrate and phosphate are presented. The on-line meters employ different measuring principles and are available in many different designs differing with respect to size, calibration and cleaning principle, user-friendliness, response time, reagent and sample consumption. A study of Danish experiences on several plants has been conducted. The list price of an on-line meter is between USD 8000 and USD 35,000. To this should be added the cost of sample preparation, design, installation and running-in. The yearly operating for one meter are in the range of USD 200-2500 and the manpower consumption is in the range of 1-5 hours/month. The accuracy obtained is only slightly smaller than the accuracy on collaborative laboratory analyses, which is sufficient for most control purposes.
Experiences with automatic N and P measurements of an activated sludge process in a research environment
Authors: Isaacs S. , Temmink H.
Published: May 2018

Some of the advantages of on-line automatic measurement of ammonia, nitrate and phosphate for studying activated sludge systems are pointed out with the help of examples of batch experiments. Sample taking is performed by cross-flow filtration and measurement of all three analytes is performed by Flow Injection Analysis (FIA). Two batch set-ups are described. In the first, one of the two 800 1 nitrifying/denitrifying tanks of a pilot-scale alternating process is employed as batch reactor, which has the advantage of a high measurement frequency and little preparatory and clean-up effort. The second consists of four 5 1 jars connected to the FIA system and allows on-line measurement of ammonia, nitrate and phosphate while performing batch reactions in parallel. Each of the four examples described was designed to study a particular aspect pertaining to Enhanced Biological Phosphate Removal (EBPR): the effect of acetate addition on aerobic P-uptake; the recovery of aerobic P-uptake after a disturbance; the interaction between denitrification and P-release when acetate is added at various rates; and the effect of stored PHB levels on denitrification by phosphate accumulating organisms.
Nutrient sensor based real-time on-line process control of a wastewater treatment plant using recirculation
Authors: Balslev P. , Lynggaard-Jensen A. , Nickelsen C.
Published: May 2018

A new generation of sensors for on-line measurement of nitrate, ammonium and phosphorus has been used for process control in a pilot-scale plant. The pilot plant is designed for nitrogen removal using the recirculation principle for pre-denitrification. It has been shown that the supply of oxygen and recirculation of activated sludge to the denitrification tank can be controlled directly by a simple control routine using an on-line measurement of nitrate and ammonium in the aeration tank. There is potential for implementing biological phosphorus removal, when the level of nitrate in the recirculated sludge can be monitored on-line.