bluuebunny/crossref_metadata_2025 huggingface dataset:
Difficulties in modelling phosphate evolution in a high-rate algal pond
Authors: Mesplé F. , Troussellier M. , Casellas C. , Bontoux J.
Published: May 2018

The High-Rate Algal Pond is an efficient treatment for controlling wastewater pollution by reducing the organic matter and the inorganic nutrient. The removal of phosphate is of great importance considering eutrophication. Deterministic modelling of the HRAP ecosystem could provide a rational basis for pond management.

The aim of this paper is to underline the difficulties in modelling orthophosphate evolution in an HRAP. A model simulating the evolution of orthophosphate concentrations in an experimental HRAP was developed taking into account the usual processes: inflow, outflow, mineralization of dead algae and uptake by phytoplankton. These processes allow us to simulate quite well the evolution of the orthophosphate concentration.

According to the literature, the precipitation of calcium phosphate (at high pH) should be taken into account in calcium-rich waters but the models allowing calculation of PO4 concentration according to pH variations neglect PO4 uptake by algae.

The problem is that both direct (uptake) and indirect (precipitation) phenomena act on phosphate removal when algae grow.

It is possible, by striking chlorophyll a and phosphorus balance, to assess the precipitation of phosphates; the results are consistent with the fact that uptake by phytoplankton is the main process acting on PO4 evolution.
The performance of a high-rate algal pond in the Moroccan climate
Authors: El Hamouri B. , Jellal J. , Khallayoune K. , Benkerroum A. , Hajli A. , Firadi R. , Outabiht H. , Nebri B.
Published: May 2018

The performance of a wastewater treatment system consisting of an anaerobic pond followed by a high-rate algal pond (HRAP) is presented. The results allowed establishment of a statistical model for HRAP design in similar climatic conditions. The results also allowed the determination of the first-order constant of faecal coliforms (FC) die-off. This constant was found to be 24.7 and 0.97 d-1, respectively, in the hot and the cold seasons. Also, some results are presented on the comprehension of the biological processes which take place in a homogeneous HRAP. They indicate that BOD and FC removals are separated in the time and that BOD removal always precedes FC die-off. Finally the results show that the helminth eggs were completely removed within an overall hydraulic retention time of 8.2 days.
Ammonium uptake by zeolite and treatment in UASB reactor of piggery wastewater
Authors: Cintoli R. , Di Sabatino B. , Galeotti L. , Bruno G.
Published: May 2018

A treatment plant of pre-screened piggery wastewater is tested at lab-scale using Italian zeolites (of very low cost) to strongly reduce the NH4+ from 1500 mg/l to 300–400 mg/l and anaerobic digestion in UASB and UASB-AF reactors to remove organics. The ion-exchange pre-treatment by zeolite leads to a reduction of toxicity of wastewater towards anaerobic microbial population and improves the UASB and UASB-AF reactors yields in organics reduction and gas production. The laboratory plant in this configuration reaches a COD removal range of 60–80% and a good reduction of effluent nutrients concentration whereas the use of a anaerobic second stage gave modest results in organics removal because of low applied organic load. A treatment cycle composed of a pre-treatment with zeolites, anaerobic digestion in UASB-AF reactor and a final treatment in an aerobic activated sludge plant is giving very good preliminary results.
Application of anaerobic digestion to the treatment of agroindustrial effluents in Latin America
Authors: Borzacconi L. , López I. , Viñas M.
Published: May 2018

A 1994 survey of high rate anaerobic reactors employed in the treatment of agroindustrial effluents in Latin America is presented. Data including number, volume and type of reactors, their evolution with time and type of effluents are discussed. Latin America has an increasing and significant participation in the application of anaerobic treatment to agroindustrial effluents. In particular, the design parameters of already operating reactors and the impact of applying this technology to the most typical effluents are analyzed. The equivalent energy of biogas that can be produced through this technology is given.
Effect of trace metals on the anaerobic degradation of volatile fatty acids in molasses stillage
Authors: Espinosa A. , Rosas L. , Ilangovan K. , Noyola A.
Published: May 2018

A laboratory UASB reactor was fed with cane molasses stillage at organic loadings from 5 to 21.5 kg COD/m3 d. With an organic load of 17.4 kg COD/m3 d, an accumulation of VFA, principally propionic acid, was observed due to little bioavailability or lack of trace metals (Fe, Ni, Co and Mo). Associated to this, the performance of the UASB reactor was low (44% COD removal efficiency), with an alkalinity ratio above 0.4. The addition of Fe (100 mg/l), Ni (15 mg/l), Co (10 mg/l) and Mo (0.2 mg/l) to the influent reduced significantly the level of propionic acid (5291mg/l to 251 mg/l) and acetic acid (1100 mg/l to 158 mg/l). The COD removal efficiency increased from 44% to 58%, the biogas production from 10.7 to 14.8 l/d (NTP) and 0.085 to 0.32 g CH4-COD/g SSV d for specific sludge methanogenic activity with propionic acid as substrate. These improved results were obtained with high COD (68.9 g/l) and organic load (21.5 kg COD/m3 d).
Anaerobic reactors for food processing wastewater treatment: established technology and new developments
Authors: Oliva L. C. H. V. , Zaiat M. , Foresti E.
Published: May 2018

This paper presents the features and the most important empirical design parameters of anaerobic filters (AF) and up-flow anaerobic sludge blanket (UASB) reactors which are the main anaerobic process units used for the treatment of low-strength food-processing wastewaters in Brazil. The technology associated with this type of reactors can be considered well established, since they are reliable operating at temperatures ranging from 15 to 30°C and at volumetric organic loading rates (OLR) lower than 5.0 kg COD.m−3.d−1. Recently, a new configuration of anaerobic reactor - the horizontal-flow anaerobic immobilized sludge (HAIS) reactor, has been proposed for the treatment of low-strength wastewaters. The sequence of fundamental and applied researches aiming to establish rational design parameters for the HAIS reactor scale-up is presented here.
Modelling sludge accumulation in anaerobic wastewater stabilization ponds
Authors: Saqqar Muwaffaq M. , Pescod M. B.
Published: May 2018

Sludge accumulation in the first anaerobic pond at the Alsamra Wastewater Treatment Plant in Jordan has been monitored over a period of years. Homogeneous distribution of sludge over the pond bottom has not been achieved. The maximum amount of sludge has not accumulated near the inlet. This is due to scouring of the settled materials near the pond inlet and outlet by the high jet velocity of the incoming flow. A model has been developed to describe the volume of sludge accumulated (VAS) in the primary anaerobic pond. The model has been derived on the basis of the non-biodegradable materials in the settled sludge. VAS has been described in terms of the mass rates (F) of suspended solids and total BOD5 in the raw wastewater and an accumulated sludge coefficient (KAS).
Nitrification processes in stabilisation reservoirs
Authors: Azov Y. , Tregubova T.
Published: May 2018

Nitrification processes in stabilisation reservoirs have a major role in improving water quality. Wastewater effluents which enter the reservoir usually have a substantial concentration of ammonia. Oxidation of ammonia to nitrates through nitrification processes increases the options of using the water for different purposes. The largest stabilisation reservoir in Israel, Maale Kishon reservoir, is used to store secondary effluents of the Haifa treatment plant and during the summer the water flows into an operational reservoir which is used for irrigation. The operational reservoir contains large amounts of fish of different species which serve for both commercial and algal control purposes. Thus, high ammonia concentrations in the stabilisation reservoir effluents may cause fish mortality in the receiving water body and are harmful to the reclamation system. Laboratory experiments with the effluents of the stabilisation reservoir were conducted in order to find out the factors that affect nitrification processes in the reservoir and to evaluate the reasons for the inhibition of these processes. It was found that environmental factors have a decisive effect over nitrification in the stabilisation reservoir. The most important factors are the temperature, solar radiation and mixing.
Nitrogen removal in pond systems with different configurations and geometries
Authors: Silva S. A. , de Oliveira R. , Soares J. , Mara D. D. , Pearson H. W.
Published: May 2018

Nitrogen removal in its various chemical forms was evaluated in a complex of waste stabilisation ponds comprising ponds of different depths and geometries. TKN and ammonia removal reached 78.5% and >90%, respectively, in the 5-pond systems with overall retention times of only 19 days. Removals were highest in the maturation ponds, and shallow maturation ponds were the most efficient. In terms of optimum pond geometry, high nitrogen and ammonia removal was compatible with optimal BOD5 removal and faecal coliform die-off. TKN and ammonia removal in these ponds could be modelled using conventional first-order equations.
Upgrading waste stabilization pond effluent by rock filters
Authors: Saidam M. Y. , Ramadan S. A. , Butler D.
Published: May 2018

Pilot-scale rock filters were constructed at the outlet of a large waste stabilization pond facility in Jordan. Their viability in upgrading the ponds' effluent was studied over a period of eleven months. This was done through studying the efficiency of four different types of locally available inexpensive materials placed in six filters and configured in three trains. The efficiency of each filter and the three combinations was evaluated. Results show that the filters can reduce the ponds' effluent content of TSS and BOD5 by 60%, TFCC by a maximum of 94% and T-P by 46%. This was achieved with a loading of 0.033-0.044 kgTSS/m3.d at an average temperature of 25 °C. Of the four media, the wadi gravel medium (3-23 cm) performed best. It was concluded that rock filters constitute a promising upgrading technique for pond effluent.
The possible reuse of wastewater treated by lagooning for the irrigation of field crops
Authors: Bunel F. , Carré J. , Legeas M. , Etienne M.
Published: May 2018

At the output from the lagooning system in the rural community of Saint-Coulomb, the effluent is of acceptable physical-chemical quality for the purposes of irrigation but care should be taken with regard to the irrigation of boron-sensitive plants. As far as contamination by metals is concerned, the effluent is of the domestic type and can therefore be used without restriction.

Monitoring of effluent quality during the summer months reveals that levels of thermotolerant coliform contamination do not always lie below the value fixed by the C.H.S.P.F. for the irrigation of plants eaten raw (104 1-1). However, no intestinal helminth eggs or salmonellaewere detected.

The levels of thermotolerant coliform contamination do not reveal any significant differences (at the 5% level) between plants irrigated with treated wastewater and plants not irrigated at all. Nor is there any significant difference between plants irrigated with standard water (TTC < 104 1-1) and substandard water. The thermotolerant coliform contamination does not only correspond to contamination by faecal coliforms.
Principles and applications of dissolved air flotation
Authors: Edzwald James K.
Published: May 2018

Principles of dissolved air flotation (DAF) discussed include: bubble formation and size, bubble-particle interactions, measures of supplied air, and modeling of the reaction and clarification zones of the flotation tank. Favorable flotation conditions for bubble attachment or adhesion to particles requires a reduction in the charge of particles and production of hydrophobic particles or hydrophobic spots on particle surfaces. A conceptual model for the bubble-particle reaction zone based on the single collector collision efficiency is summarized and discussed. An alternative modeling approach is considered. Clarification or separation zone modeling is based on particle-bubble agglomerate rise velocities. The application of DAF in drinking water treatment is addressed beginning with summaries of design and operating parameters for several countries. DAF should not be considered as a separate process, but integrated into the design and operation of the overall treatment plant. This concept shows that flocculation ahead of DAF has different requirements regarding floc size and strength compared to sedimentation. The efficiency of DAF in removing particles and reducing particle loads to filters needs to be integrated into DAF plant design. The impact on filtration performance is illustrated. Finally, fundamental and applied research needs are addressed.
A kinetic model for dissolved air flotation in water and wastewater treatment
Authors: Fukushi K. , Tambo N. , Matsui Y.
Published: May 2018

A kinetic model for DAF is presented. The author's kinetic model consists of the equations for describing a process of bubble-floc collision and attachment in a mixing zone, and a rise velocity of bubble-floc agglomerates in a flotation tank. The attachment process is formulated on a population balance model with bubbles and flocs as a flocculation in a turbulent flow. The rise velocity of bubble-floc agglomerates is formulated with size of flocs and composition of flocs including the floc density function and attached bubble number. The experimental verification was carried out, using a batch flotation tested and a mini-plant with synthetic clay suspension and colored water. The results successfully verify the validity of the model. From a given condition such as floc size and attached bubble number, the rate and extent of removal by DAF can be readily assessed by the model. A single-collector collision model, often discussed in some occasions, seems to be not useful to describe the DAF process.
The use of selective and direct DAF for removal of particulate contaminants in drinking water treatment
Authors: Malley James P.
Published: May 2018

Cationic polymers were found to coat bubbles resulting in charge reversal and increasingly positive EPM. Batch bench-scale dissolved air flotation (DAF) studies show promising benefits from the addition of cationic or non-ionic polymers to the saturated recycle line of conventional DAF. In cases where low turbidity, low color waters are being treated, direct DAF compared well with conventional DAF. Polymer addition improved the percentage solids of the float. Anionic polymers were not found to be effective. Further research at the pilot and full-scale is needed to verify these findings.
Comparison of dissolved air flotation and direct filtration
Authors: Ferguson C. , Logsdon G. S. , Curley D.
Published: May 2018

Direct filtration with and without pre-ozone, and dissolved air flotation and filtration were evaluated for clarification of high quality reservoir water in Greenville, South Carolina, USA. Goals of the study included production of low turbidity filtered water and control of algae, iron and manganese, and disinfection by-product precursors. The dissolved air flotation treatment train gave much longer filter runs than direct filtration, when both processes met the 0.10 NTU goal for filtered water quality. Use of pre-ozone was beneficial for direct filtration. Removal of TOC, DBP precursors, and iron and manganese were similar for both processes.
Evaluation of dissolved air flotation process for water clarification and sludge thickening
Authors: Arora Harish , DeWolfe James R. , Lee Ramon G. , Grubb Thomas P.
Published: May 2018

Dissolved air flotation was evaluated using pilot and bench tests for water clarification and sludge thickening. A DAF pilot study was conducted on one water source with low turbidity, high color, high organic content and algal blooms. For this water, coagulation with alum, cationic polymer and pH around 6.1 resulted in removal of turbidity, color and algae. THMFP and TOC were removed by approximately 25 and 50 percent, respectively. A river water source was used in another pilot study to identify limits on source water turbidity for the DAF process. Tests conducted with induced high turbidity values resulted in filtered water quality with low turbidity and complete removal of color. TOC was removed by approximately 35 percent, however, inconclusive results were obtained for THMFP removal. Based on these pilot test, DAF is a viable clarification process, especially for source waters with low turbidity (infrequent spikes upto 100 NTU), high algal blooms and high color. Bench-scale DAF assisted sludge thickening resulted in performance similar to gravity thickeners. High recycle ratios (around or greater than 100 percent) were required for effective sludge thickening.
Rational design of packed saturators
Authors: Haarhoff Johannes , Rykaart E. Maritz
Published: May 2018

The paper describes the development of a mathematical model for predicting the mass transfer efficiency of packed saturators used for dissolved air flotation. The first part of the paper deals with the equilibrium condition, i.e. the maximum attainable air concentration with a packed saturator at 100% transfer efficiency. The second part derives a kinetic model based on concentration-driven diffusion and the Lewis-Whitman two-film theory. The transfer rate constant across the laminar liquid film and the wetted packing area are estimated with the Onda correlations. The model is finally used to demonstrate the effects of hydraulic loading, packing depth, packing size and temperature on saturator efficiency.
Design parameters for dissolved air flotation in South Africa
Authors: Haarhoff Johannes , van Vuuren Lucas R. J.
Published: May 2018

Dissolved air flotation has been used in South Africa for more than 25 years in the field of water and waste-water treatment, with practically all the development and verification done locally. This substantial body of knowledge and experience was recently condensed into a document titled A South African Design Guide for Dissolved Air Flotation. A general literature survey was combined with a detailed survey of 26 dissolved air flotation plants operating in Southern Africa, to arrive at suggested design parameters. Two broad categories of applications were covered in the guidelines - those of water clarification, and of activated sludge thickening.

A clear trend emerged from the data collected. Drinking water clarification plants were generally designed within a fairly narrow range of the most design parameters, and the perception of operators and managers was that these clarification plants performed very efficiently. Sludge thickening plants, on the other hand, showed considerable variability in terms of most design parameters, and the general perception of its efficiency consequently varied from highly positive to negative.

The paper includes summaries of the ranges of the actually surveyed design parameters, the suggested design values and a comparison with typical design values available from other countries.
Birmingham Frankley water treatment works redevelopment
Authors: Schofield T.
Published: May 2018

Severn Trent Water are currently undertaking an extensive capital programme to enhance water treatment facilities at many of its major works. This paper describes the various aspects of the Birmingham Water Treatment Plant Redevelopment Strategy with specific emphasis on the factors that lead to the selection of dissolved air flotation (DAF) as a main stage of clarification and subsequent construction of the largest DAF plant in the world. The design, construction and operation of the plant are reviewed with particular attention to water quality and the use of carbon dioxide within the process stream to produce a stable treated water.
Removal of cadmium from dilute solutions by flotation
Authors: Zouboulis Anastasios I. , Matis Konstantine A.
Published: May 2018

Cadmium constitutes a priority pollutant existing in waste streams from metal plating and various other industries. The removal of this toxic metal employing the dissolved air flotation technique was investigated in laboratory batch experiments; the mechanism of precipitate flotation as the respective hydroxide was followed. Main examined parameters include: recycle ratio, pH of the solution, concentrations of added surfactant (sodium dodecyl sulphate), frother (ethanol) and cadmium. Promising results have been obtained, at the pH range between 10 and 11 approximately, showing the significance of flotation as a separation process in water and wastewater treatment for dilute solutions (around 10 mg/l of metal). Under the optimum conditions removal of cadmium was near to 100%, while the remaining concentration in the solution after flotation was less than 0.10 mg/l. A comparison was also attempted between two flotation techniques applying different bubble generation methods, i.e. dissolved air and dispersed air flotation. These experiments run in parallel and under the same conditions.
Epidemiological study of swimming-associated illnesses relating to bathing-beach water quality
Authors: Kueh C. S. W. , Tam T.-Y. , Lee T. , Wong S. L. , Lloyd O. L. , Yu I. T. S. , Wong T. W. , Tam J. S. , Bassett D. C. J.
Published: May 2018

The water quality objective or indicator of bathing beaches is established on the basis of epidemiological data of swimming-related illnesses in the local population. It needs to be updated and refined in light of changes in the composition, health status and recreational activities of the community. A major epidemiological study was conducted in Hong Kong in 1992 involving interviewing 25000 beach-goers on the health effects of exposure to bathing water. The results indicated that the total incidence of swimming-related illness symptoms was 41 per 1000, higher than the 30 per 1000 found in 1987. Eye, skin and respiratory symptoms were 2-20 times more prevalent in swimmers than in non-swimmers. Only gastrointestinal (GI) symptoms were directly related to the pollution level and bacterial content of beach water. Turbidity of beach water was closely linked with GI and highly credible GI symptoms and might be used as a monitoring tool and a parameter in the beach water quality objective. There was also a direct correlation between GI symptoms and the number of Clostridium perfringens, Aeromonas spp., Vibrio cholerae (non-O1) in beach water. No direct relationship between GI symptoms and E. coli or faecal coliforms could be identified in this study.
Comparison of three laboratory devices for UV-inactivation of microorganisms
Authors: Sommer R. , Cabaj A. , Schoenen D. , Gebel J. , Kolch A. , Havelaar A. H. , Schets F. M.
Published: May 2018

UV inactivation experiments of microorganisms have been performed and published by various workers for decades. Resulting data even of the same species of microorganisms may show important differences in UV-susceptibility. The reasons for these varying results could be found either in different biological conditions like culturing methods for preparing the test organisms or in technical problems regarding UV-irradiation equipment and dose measurement.

Therefore three groups working on UV inactivation performed a collaborative study to find out which influences could be responsible for varying results in laboratory UV experiments. Each working group had developed a laboratory UV irradiation apparatus, which differed in technical construction and method for UV dose measurement. For our study we used as a test organism spores of Bacillus subtilis ATCC 6633 which were cultured in large quantity, freeze-dried and stored for all following experiments. Thereby we established controlled biological conditions. The first series of experiments in 1992 showed that differences in inactivation curves did occur, related especially to dose distribution in irradiation vessels, in irradiation geometry and in partial shadowing of UV light. Subsequently the irradiation procedure and methods for dose measurement were improved resulting in consistent, reproducible and comparable results. The equation of the regression curve was: log (N/N0) = −0.013 D + 0.18. A 2 log reduction would require a dose of 169 ± 11 J/m2, a 3 log reduction 241 ± 9 J/m2, respectively (level of significance: a = 0.05).

In recent years bioassay methods have been suggested in order to evaluate UV-disinfection plants. Therefore it will be of increasing public health interest to ensure the quality of laboratory UV irradiation devices used for calibration of test-organisms for these bioassays.
Integrated water quality management: getting people involved in the Jukskei River
Authors: van Veelen M. , van Zyl F. C.
Published: May 2018

Although the Department of Water Affairs and Forestry has committed itself to public participation with regard to water quality management in South Africa, no formal structure exists as yet within which this can take place. The Jukskei River Water Quality Steering Committee, which consists of representatives of various government departments, the Provincial Government, local authorities as well as non-government organisations and community-based organisations, therefore functions without a legal framework and without funds of its own. Nonetheless, the committee has been highly successful in co-ordinating various actions such as an in-depth study of the catchment and various public awareness campaigns. The latter were specifically aimed at changing the value systems of the community in the Jukskei River Catchment, as this was found to be one of the major stumbling blocks in addressing the various water quality problems in the catchment.
Viral inactivation by potassium ferrate
Authors: Kazama Futaba
Published: May 2018

The kinetics of inactivation by potassium ferrate were studied using a bacteriophage, F-specific RNA-coliphage Qβ as a viral model. The inactivation appeared to be expressed by Hom's model in phosphate buffer at pH 6, 7, and 8. The rate of inactivation depended on pH; the lower pH, the faster inactivation observed. To consider the mechanism by which ferrate caused inactivation, the efficiency of inactivation was checked after ferrate decomposition in buffer. Effective inactivation following Hom's model was also observed after the complete decomposition of ferrate ion; however, the efficiency of that inactivation disappeared by the addition of sodium thiosulphate, suggesting that rather long-lived oxidative intermediate was generated by the decomposition of ferrate ion. The intermediate might take part in the inactivation.
A citizen's approach to integrated river basin management
Authors: Williams T. C. , Dee P. E.
Published: May 2018

This paper describes the success of an ad hoc citizen group in developing an integrated water resource plan for the Santa Fe River in the high desert of New Mexico. Much of the time the Santa Fe River, which runs through the centre of town, is dry because of impoundments for water supply. Water management responsibilities in the area are divided between eight government agencies. Each agency has its own narrowly perceived agenda for managing that aspect for which it is responsible. It was apparent that a holistic approach to water management was sorely needed. An ad hoc citizen committee was formed without government support (either technical or financial), to attempt to bring some rational planning to the use of existing water resources in the growing community.
Influence of salts and montmorillonite upon heat inactivation of poliovirus in sterile water
Authors: Quignon F. , Schwartzbrod L.
Published: May 2018

Using semi-purified type-1 poliovirus we show that the viral inactivation rate in sterile deionised water is not influenced by the initial virus titer, remains unaffected by the saline concentration (ionic strength) of the medium nor by the valency of the introduced cations.

In the presence of purified Na-montmorillonite and in similar conditions we observe the same viral decay rates. In particular the presence of clay (at least up to 205 mg.l−1) does not provide viruses with any protective effect against heat, as experiments carried out at different temperatures do not reveal any difference between viral inactivation rates due to the presence of montmorillonite.

Furthermore viral decay rates obtained with or without clay both plot against temperature on the same regression line, following an Arrhenius-like equation with an excellent correlation coefficient.
A survival study of Escherichia coli in a south African river using membrane diffusion chambers
Authors: de Wet C. M. E. , Venter S. N. , Rodda N. , Kfir R. , Steynberg M. C. , Hohls D. , du Plessis G.
Published: May 2018

Studies to describe the survival of Escherichia coli were performed at two sites in a river. The one site was dominated by domestic discharge and the other by industrial inputs. E coli suspensions within membrane diffusion chambers were immersed in the river at the selected sites. An identical chamber was submerged in river water in the laboratory as a comparison. Two test runs were performed, one during winter (July) and one during summer (December). Samples to determine the survival of E coli was taken on a scheduled basis. Results obtained showed no significant difference between the survival pattern of E coli as determined during the summer and winter periods or in the different parts of the river. The same survival pattern was observed for the studies performed in the laboratory.
The development of South African water quality guidelines for the natural aquatic environment
Authors: MacKay H. M. , Roux D. J. , Ashton P. J. , van Vliet H. R. , Jooste S.
Published: May 2018

This paper describes the progress made by the Department of Water Affairs and Forestry in the development of documented water quality guidelines for aquatic ecosystems in South Africa, which will be able to take into account local and site-specific conditions. Proposed guidelines for toxic substances, nutrients and physico-chemical variables are described.
Detection of enteroviruses in marine waters by direct RT-PCR and cell culture
Authors: Reynolds K. A. , Gerba C. P. , Pepper I. L.
Published: May 2018

Sewage outfalls and storm water runoff introduces pathogenic human enteric viruses into marine coastal waters, which may pose a potential public health risk. Although members of the enterovirus group have been suggested as possible indicators of sewage pollution in marine waters, the lack of rapid, sensitive and cost effective methods have prevented routine monitoring in the United States. This study compared traditional cell culture and direct RT-PCR (reverse transcriptase-polymerase chain reaction) amplification for detection of an enterovirus. Poliovirus could be recovered from 100 L of artificial seawater with an average efficiency of 77%, using adsorption and elution from electronegative filters. Viruses were eluted from the filters with 1.5% beef extract for viruses (BEV) adjusted to pH 9.5 and reconcentrated by organic flocculation to a volume of 30 mL. Substances which interfered with detection by RT-PCR were removed by treatment of the concentrates with sephadex and chelex resins. Direct RT-PCR could detect 2.5 and 0.025 PFU (plaque forming units) for single (25 cycles) and double PCR (2 × 25 cycles) in 10 μL of pure culture poliovirus samples, respectively. These methods are currently being applied to assess the occurrence of enteroviruses at marine bathing beaches influenced by sewage discharges.
Detection of enteric adenoviruses in south African waters using gene probes
Authors: Genthe B. , Gericke M. , Bateman B. , Mjoli N. , Kfir R.
Published: May 2018

Gene probes developed locally for both enteric Adenoviruses 40 and 41 were used to determine whether these viruses were present in both raw and treated waters. Approximately sixty water samples were concentrated by ultrafiltration and analysed directly for the presence of enteric adenoviruses. Three pretreatment techniques, namely sephadex columns, cellulose fibre and GenecleanTM were tested for the removal of inhibitory substances from concentrated water samples. The effect of chlorine treatment on viral detection using gene probe hybridization was also examined by exposing adenoviruses to chlorine concentrations of up to 20mg/l for 1 hour. Enteric adenoviruses were detected in up to 59% of both raw and treated waters analysed. Cellulose fibre and GenecleanTM were found to successfully remove inhibitory substances from concentrated raw waters. Viral DNA was detected after exposure to a range of chlorine concentrations indicating that the viruses detected in the treated waters may have been inactivated virus particles.
A novel method for the detection of infectious rotavirus from water
Authors: Sellwood J. , Wyn-Jones P.
Published: May 2018

An easy low-cost cell culture and ELISA system is described that is capable of detecting low numbers of infectious rotavirus.
Application of polymerase chain reaction to detect RNA coliphage Qβ in environmental water samples
Authors: Sunun Limsawat , Kamiko Naoyuki , Yamamoto Kazuo , Ohgaki Shinichiro
Published: May 2018

An RT-PCR technique for direct detection of enteric viruses in environmental water samples was developed by using RNA coliphage Qβ as a model virus. RNA coliphage Qβ was prepared from the lysate broth of single-plaque-isolated stock and extracted by direct heating. The sensitivity of the PCR amplification was improved by optimizing the parameters to be evaluated for efficient PCR including KCl in buffer components, Taq polymerase, annealing temperature, and number of cycles. The higher KCl concentration (up to 90 mM) in reaction incorporating with lower Taq polymerase concentration (0.5 unit/40 μl total reaction) caused quite low sensitivity and inconsistency of RT-PCR. The KCl concentration (30 to 90 mM) implied no significant effect to the yields of PCR products when higher Taq polymerase (1.0 to 2.5 units/40 μl total reaction) was included. Increasing the number of cycle from 25 to 35 cycles was able to increase the sensitivity. The increasing of annealing temperature reduced amplifying background products seen on gel electrophoreses. The maximum sensitivity is 0.3 PFU/reaction using condition of 35-cycle amplification with Taq polymerase 2.5 units and 55°C annealing temperature. This RT-PCR technique will be used as a protocol for further study for enteroviruses. The success of detection of indigenous RNA coliphages (group III) in night soil sample using the developed RT-PCR methods means that the developed method has great potential as a direct detection method of viruses in environmental sample. The inconsistency of the detection limit between plaque assay and RT-PCR assay may be caused by the effects of inhibitors in night soil sample. Further study on the relationship between plaque assay and PCR assay is required.
Detection of legionella bacteria in sewage by polymerase chain reaction and standard culture method
Authors: Roll Bruce M. , Fujioka Roger S.
Published: May 2018

Legionella bacteria are ubiquitous in environmental waters. Only a few species of Legionella , especially, L. pneumophila are pathogenic to humans and cause a sometimes fatal Legionnaires disease as well as a less fatal disease called Pontiac fever. The presence of Legionella in sewage and aerosolized sewage is the subject of this investigation because reuse of sewage may involve the exposure of people to aerosolization, the mode of transmission of Legionella bacteria. The objective of this study was to determine the prevalence of Legionella species and L. pneumophila in wastewater and their fate after various stages of treatment. The polymerase chain reaction (PCR) and standard culture method were utilized to detect Legionella species and L. pneumophila. PCR results indicated that Legionella species were present at levels > 103 cells / ml during all phases of sewage treatment including chlorinated effluents. Culture results indicated levels at least one log lower than seen with PCR. Legionella species were also recovered from air samples collected from secondary aeration basins at levels < 103 cells/ml. PCR was shown to be the most rapid and sensitive method for detecting Legionella in sewage.
Detection and enumeration of giardia cysts in river waters of Hong Kong by flocculation-percoll/sucrose gradient-immunofluorescence method
Authors: Ho Bella S. W. , Tam T.-Y. , Hutton Primrose , Yam W. C.
Published: May 2018

We have established a simple procedure for the enumeration of Giardia cysts in environmental waters of Hong Kong. The procedure involves concentrating water or sewage samples by the flocculation-percoll/sucrose gradient method followed by a modified tube method using immunofluorescent staining containing fluorescein isothiocyanate labelled anti-Giardia monoclonal antibodies. Enumeration of cysts was carried out using fluorescent microscopy. This procedure has the highest recovery rate (61%) compared with other conventional procedures tested (0-4%). This method was successfully applied to the detection and enumeration of Giardia cysts in water samples collected from two selected rivers of Hong Kong, Shing Mun River and Lam Tsuen River. Preliminary results indicate that water of both rivers has high counts of Giardia cysts.
Detection of giardia and cryptosporidium in marine waters
Authors: Johnson D. C. , Reynolds K. A. , Gerba C. P. , Pepper I. L. , Rose J. B.
Published: May 2018

Raw sewage disposal in marine waters is a common practice in many countries. This practice raises health risk concerns of possible transmission of Giardia and Cryptosporidium. Both of these protozoa have been shown to be transmitted by recreational swimming. To date no studies have determined the efficiency of their detection and concentration in marine waters. This study evaluated the efficiency of their detection in tap water and from marine waters in Hawaii with two different filter types. This study compared a polypropylene fiber cartridge filter, DPPPY (1.0 μm nominal porosity) (Cuno, Meriden, CT) which is typically used for parasite detection and the Filterite negatively charged filter (0.45μm) (Filtemp Sales, Inc., Phoenix, AZ). The latter would allow for both viruses and parasites to be concentrated simultaneously. The organisms were removed from the filter by passing the eluent through the filters in the opposite direction of collection and detected by indirect immunofluorescence antibody staining specific for Giardia and Cryptosporidium. Processing was simpler and faster with the Filterite filter and the overall efficiency for both Giardia and Cryptosporidium detection was greater. These methods are currently being used for the detection of the oocysts and cysts at bathing beaches in Hawaii impacted by marine sewage discharge.
Health effects of mercury ingested through consumption of seafood
Authors: Valentino L. , Torregrossa M. V. , Saliba L. J.
Published: May 2018

It is known world-wide literature that seafood consumption is the main source of mercury intake in people not occupationally exposed. Several studies on the presence of mercury in sea water, sediment and fish and its effects on human health have been carried out in many countries in the Mediterranean area such as Greece, Italy and Jugoslavia. Few data have been published on Sicilian coastal population, consumers of high amounts of fish and on seawater status as the starting point of alimentary chains involving marine food. This study was carried out in July 1991 and July 1992 to determine total mercury and methylmercury levels in selected populations of the coast of Sicily: fishermen in a little island, Favignana, located west of Sicily, where the population can be considered at risk due to its high fish intake, and fishermen of a small fishing village (Porticello), near Palerno. As a control group, a sample population in a town located in the middle of Sicily (Valledolmo), where consumption of fish and seafood was quite inexistent and an urban population (inhabitants of Palermo) with variable quantities of seafood in diet were taken. Following the guidelines of WHO (1982) the subjects were interviewed by a dietary questionnaire. One hundred and twenty three hair samples, cut from the occipital area, were analysed for total mercury and methylmercury concentrations. Following the standard protocol for mercury analysis in hair, only those specimens exceeding 10 μg/g total Hg were analysed for methylmercury content. The results of study on 98 fishermen and their families with hair samples have shown that the dietetical weekly intake of seafood is related to the concentration values of total mercury and methylmercury that were found in the analysis. Only 19 subjects have been found with total mercury concentration values above the security level (> 6 μg/g total Hg) and 8 have been analysed for methylmercury. From our data, it appears that in this Sicilian area, when there aren't industrial and natural sources of Hg, even if the population eats a large amount of locally caught fish, the concentration of Hg found in hair samples never reaches risk levels.
Treatment of septage using single and two stage activated sludge batch reactors systems
Authors: Andreadakis A. D. , Kondili G. , Mamais D. , Noussi A.
Published: May 2018

The cyclic or sequencing batch activated sludge process was applied for the treatment of septage originating from cesspools serving non-sewered areas. Single and two stage systems were investigated in bench scale units. The single stage aerated system was capable in removing practically all the biodegradable COD and producing a well stabilised excess sludge with excellent settling and thickening characteristics. With respect to nitrogen the average removal rate was to the order of 70%, but the performance was unstable due to periodic strong inhibition of the nitrification process. Subsequent treatment in a second stage aerated unit improved nitrification but did not result in higher nitrogen removal rates due to the increased concentrations of oxidised nitrogen. An anoxic second stage post denitrification unit resulted in an overall nitrogen removal of 88%, through a substantial reduction of nitrates. Further improvement of the system, with nitrogen removal of about 95% and average effluent nitrogen concentrations lower than 10 mg.1−1, can be achieved by adoption of a two stage system consisting of a first aerated stage unit, followed by a second stage unit with alternating aerated and anoxic cycles and addition of external carbon during the anoxic cycle.
Modeling of pollution from the wastewater discharge of the city of Limassol
Authors: Christodoulou G. C. , Ioakeim I. , Ioannou K.
Published: May 2018

The paper presents a numerical modeling study aimed at a preliminary assessment of the impact of the planned sea outfall of the city of Limassol, Cyprus, on the waters of Akrotiri bay. First the local meteorological and oceanographic conditions as well as the loading characteristics are briefly reviewed. Two-dimensional finite element hydrodynamic and dispersion models are subsequently applied to the study area. The results of the former show an eastbound flow pattern under the prevailing westerly winds, in general agreement with available field observations. The spread of BOD and N under continuous loading is then examined for eastward as well as for westward flow as an indicator for the extent of pollution to be expected. The computed concentrations are generally low and confined to the shallower parts of the bay.
Distribution of chemical polluting factors in south Italian seas along Calabria coastal waters (low tyrrhenian sea, high ionian sea and straits of Messina)
Authors: Decembrini F. , Azzaro F. , Crisafi E.
Published: May 2018

This report is dealing with the presence of Dissolved/Dispersed Petroleum Hydrocarbons (DDPH) synthetic detergents (ABS) and Total Phenols (T-PHE) in 150 stations positioned along the Calabria coastal waters as well as off-shore. Data were gathered during four different seasonal cruises (from 1990 to 1992). In order to identify areas of possible environmental risk, threshold values based on background mean concentrations present in the Mediterranean Sea were determined for each parameter.

DDPH exceed the concentration limit of 0.4 ppb in areas near urban settlements only and are due mainly to untreated municipal sewages. In winter and spring high values were also registered in the mouths of some rivers that carry polluting substances of different origin. Generally the values of ABS resulted to be below the 3 ppb limit, but measured up to 127 ppb in well localized areas and were linked T-PHE and DDPH, thus indicating that their origin is primarily due to industrial sewages. Concentration of Total Phenols almost always showed values below the threshold (4.0 ppb); the highest values (about 50 ppb) presented a similar distribution as that of DDPH.

In conclusion, the overall environmental conditions are quite satisfactory, except for some localized areas where sometimes parameters exceeded limits simultaneously.
The role of standardization in the protection of the environment - the Mediterranean Sea
Authors: Tsimillis K. , Pithara N.
Published: May 2018

Standards have been used for many years as a tool to improve quality. Recently, the lowering of trade barriers and the need for transfer of technology have increased and widened the role of standardization and the international cooperation through it.

Standardization programmes, both at the national and international level, are now focused on the protection of health and safety of the consumer and the environment. In the case of environmental protection ISO, CEN and other organizations are working very hard to establish appropriate requirements.

The Mediterranean Sea represents a special example regarding marine pollution. Being a “closed” sea and at the same time the receptor of huge quantities of effluents from all kinds of human activities, the Mediterranean Sea (our sea) is already in danger! A series of Protocols and Conventions, already agreed on, provide the necessary basis for its protection. However, problems still exist regarding the implementation of the provisions of these documents.

In this paper the way standards can contribute to the protection of the environment and the Mediterranean in particular is illustrated. The presentation also underlines the need to enhance international cooperation and to promote versatile and efficient implementation mechanisms through it.
Fish processing wastewater: production of internal carbon source for enhanced biological nitrogen removal
Authors: Battistoni P. , Fava G.
Published: May 2018

A plant treating fish processing wastewaters was monitored over one year to prove the practical advantages achievable through the internal production of RBCOD. A clear improvement of the effluent quality with lower NOx-N content and the disappearance of fluctuation of nitrates were obtained. Changing the equalization management from aerobic to anoxic, it was possible to utilise battered waste as internal carbon source. Plant reliability was confirmed during the entire observation period. The plant broke down twice electromechanically and it required more than 24 days to restore normal plant conditions. The advantages obtained overcome the risks associated with the new scheme adopted.