bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water, Health, Recreation and Tourism
Authors: Wade Alan 
Published: May 2018

Tourists and holiday makers have a closer than “normal living” association with the water cycle. Tourists are particularly sensitive to the effects of changing water quality as almost any traveller can attest to.
In this paper, we will be looking not at drinking water but at the health effects of water-based recreational pursuits. These pursuits range from taking a spa to eating shellfish in a polluted estuary (Table 1). Attention will be drawn to the very substantial costs to the tourist industry of not paying attention to water quality problems. Water quality problems are often easily dealt with, so their continued existence can reflect badly on the leisure industries.TABLE 1Recreational WatersClosed or Controlled Recreational WatersSwimming pools, spas, slides, float tanks, wavepools and hydrotherapy pools.Open Recreational WatersBeaches, estuaries, lakes and streams.
The Occurrence of Enteric Viruses in Polluted Water, Correlation to Indicator Organisms and Factors Influencing their Numbers
Authors: Geldenhuys J. C. , Pretorius P. D. 
Published: May 2018

Samples from a stream polluted with treated domestic effluent were examined for the presence of enteric viruses and indicator organisms viz. total and faecal coliforms, faecal streptococci and coliphages. Strong seasonal patterns in both the occurrence and number of enteric viruses, coliphages, and to a lesser extent faecal streptococci, were observed. The incidence of the highest and lowest number of enteric viruses and coliphages plotted on a time scale followed a sine curve as opposed to the variations of temperature which followed an inverted sine curve. Indications are that the survival of these organisms is inversely proportional to temperature with lower temperatures (below 13°C) being conducive to a slower die-off rate. The square of the correlation coefficient between the viral numbers and temperature was calculated at R2 = 0.4. This coefficient of determination only improved to R2 = 0.46 by combining data from other physical and physico-chemical and biological determinations. Temperature may be considered a useful aid in predicting the possible presence or absence of enteric viruses in raw water.
Of all the indicator organisms examined only results on coliphages behaved similar to that of enteric viruses and should therefore be considered the best biological indicator for viral behaviour under these circumstances.
Disinfection of Sewage Effluent with Peracetic Acid
Authors: Baldry M. G. C. , French M. S. 
Published: May 2018

Novel products based on peracetic acid (PAA) have recently been developed for the disinfection of sewage and sewage effluents. The efficacy of such products has been assessed under both laboratory and operational conditions.
Comparative laboratory studies of the effects of peracetic acid, chlorine dioxide and chlorine on indicator bacteria in secondary sewage effluent have shown peracetic acid to be a viable alternative to these halogen biocides.
In a trial carried out at two small rural works, PAA was dosed into secondary effluent from either an activated sludge plant or a percolating filter bed prior to tertiary lagoon treatment. LOW levels of PAA greatly enhanced the natural decline in coliform levels across the lagoon, enabling much lower concentrations of bacteria to be discharged into the receiving streams.
In another trial, secondary effluent from an activated sludge plant was treated before discharge into a stream leading to the sea. Coliform concentrations were greatly reduced along the watercourse downstream from the plant.
Effect of Suspended Solids on Inactivation of Poliovirus and T2-Phage by Ozone
Authors: Kaneko Mitsumi 
Published: May 2018

This study was conducted to quantify the effects of suspended solids on virus inactivation by ozone and to develop guidelines for ozone dosages in disinfection using poliovirus and T2-phage. The curve of virus count reduction could be divided into three phases: an initial large reduction which occurred within 30 seconds of contact between the viruses and ozone; a subsequent logarithmic reduction; and finally, a slow reduction in response to decreasing ozone concentrations. The reduction of the viruses by ozone is expressed well by the Collins-Selleck Model.
The presence of suspended solids significantly reduced the rate of virus inactivation. Using data obtained in this study, the model equation gives the following estimates: if 99.99% inactivation is required with a contact time of 5 minutes, an ozone residual of 0.6 mg/l is necessary when suspended solids are not present; with kaolin levels of 1 and 10 mg/l, ozone residuals of at least 0.9 and 3.7 mg/l, respectively, are necessary for 99.99% inactivation in 5 minutes. If more than 1 mg/l of an autoclaved activated sludge is added to the water, the commonly applied dose of ozone is not sufficient to produce more than a 4 log10 reduction in 5 minutes.
Estimating Adsorption Equilibria of Phenolics on Synthetic Resins from the Polar and Nonpolar Properties of the Molecule
Authors: Groff K. A. , Kim B. R. , Gould J. P. 
Published: May 2018

The adsorption of aromatic compounds on synthetic resins from aqueous solution was studied in order to develop a methodology by which adsorption equilibria, in a single- solute system, can be predicted from the physical-chemical properties of a compound of interest, and the adsorption isotherm of a reference compound.
To develop this methodology, physical properties of 13 substituted phenols were described by linear free energy relationships (LFER) (Hammett polar constant and molar attractive constant) and were correlated with parameters in the Freundlich adsorption isotherm.
The methodology was tested using data extracted from the literature and was found to be able to predict adsorption equilibria within a median percent deviation between the experimental and predicted data of 35.73%.
Effect of Wastes Quality on Treatment Efficiency with Duckweed
Authors: Oron Gideon , Willers Hans 
Published: May 2018

Outdoor experiments with Lemnagibba (a duckweed species) grown in mini-ponds were conducted for several months during summer 1986. Duckweed was grown on two different types of wastes: (a) Digested sludge after an anaerobic phase of the settled fraction of domestic sewage mixed with the supernatant (experiment A); and (b) supernatant of domestic sewage at three different salinity levels defined by electrical conductivity (EC) (control, 4.0 dS/m and 6.6 dS/m) (experiment B).
The results indicate that duckweed can grow well on a mixture of digested sludge and supernatant. Dry yield (experiment A) was in the range of 10 to 15 g/m2 per day with a protein content close to 30 percent. Effluent quality meets agricultural irrigation criteria. Duckweed growth on saline waste was mostly negatively affected when the electrical conductivity of the influent exceeded 4 dS/m.
Experimental Studies on Biological and Chemical Oxidation of Dispersed Oil in Seawater
Authors: Literathy P. , Haider S. , Samhan O. , Morel G. 
Published: May 2018

With an understanding of the different physical, chemical and biological weathering processes, a series of laboratory experiments were conducted to describe biological and chemical oxidation processes at realistically low concentrations of physically and chemically dispersed oil in seawater by incubating living and sterilized samples spiked with oil alone, oil-dispersant mixture and dispersant alone, under light and dark conditions. Biological oxygen demand and photosynthetic oxygen production were characterized by the variation in dissolved oxygen, whereas the degradation of oil and dispersant was followed by the variation in total extractable matter and surfactant concentration, respectively. Gas chromatography, infrared and fluorescence spectrophotometry were used for the characterization of the petroleum and its degradation compounds.
Biological oxidation was considered the major process in the living seawater sample incubated in the dark, and chemical oxidation, i.e., photo-oxidation, in the sterilized seawater sample exposed to light. In the early stages of each experiment, biodegradation of the physically dispersed oil progressed faster than the chemically dispersed one due to the concurrent degradation of the dispersant and the limited assimilative capacity of the seawater. The n-alkanes, mono- and dicyclic aromatic compounds showed significant biodegradation and limited photo-oxidation, whereas polycyclic aromatics were mainly photo-oxidized. Photo-oxidation was stimulated in the chemically dispersed oil. Synergistic degradation was observed when biological and chemical oxidation progressed simultaneously.
Relation Between Redox Potential and Oxygen Levels in Activated-Sludge Reactors
Authors: Heduit Alain , Thevenot Daniel R. 
Published: May 2018

The importance of dissolved oxygen level in determining the platinum electrode potential in activated sludge has been clearly demonstrated by current-potential curves plotted at different oxygen concentrations.
Tests have been carried out, in the laboratory and in full scale treatment plants,to define the relationship between the platinum electrode potential at equilibrium (Eh) and the dissolved oxygen [O2] concentration in the activated sludge. These two parameters obey a law of the form Eh = a + b log [O2]. The measured values of coefficents a and b differ widely to those found from the oxygen reduction reaction in water (a = 0.8 V at pH 7 and b = 15 mV per decade).
Factors a and b mainly depend on the sludge loading, the aeration conditions and the sludge concentration. Using non–polished stationary platinum ring electrodes, the following values of a. were obtained (at pH between 7 and 7.6) : + 410 mV/NHE for sludge aerated for several hours without feeding, + 265 mV/NHE for over-aerated/low-loaded sludge (Cm = 0.2 kg BOD.kg MLVSS−1. day−1) and + 180 mV/NHE for high-loaded activated sludge in plug-flow system (Cm = 1 kg BOD.kg MLVSS−1.day −1). Factor b would seem to lie between 55 and 65 mV when the sludge is continuously aerated without feeding.At low loads with excess aeration, it lies between 70 and 90 mV. When the medium is slightly septic at low dissolved oxygen concentrations (insufficient daily aeration time, high sludge concentration or aerators shut down for too long periods), factor b increases and can reach 200 mV. In the same way, at high loads, factor b can become 150 mV.
These results demonstrate the importance of dissolved oxygen concentration in the mechanisms which determine the metal electrode potentials in activated sludge. They also illustrate the role that other electroactive species play in the process. The type and concentration of these species depend on parameters such as the sludge loading, the overall oxygen supply, the aeration sequence and the sludge concentration.
An Optimization Study of the Planning of Water Pollution Control for Majiagou Stream in Harbin, China
Authors: Gong Yang , Peishi Qi , Baozhen Wang , Jun Sui 
Published: May 2018

A study on the optimization planning of water pollution control for Majiagou Stream in Harbin was carried out. Four water pollution control options were considered. The option regarded as most feasible, both technically and economically, involved the construction and operation of a wastewater treatment works with a capacity of 150,000 m3/day on the upper reach of the stream. The effluent would be discharged into the upper reach of Majiagou Stream and would be used as a water source for the stream, while an interceptor sewer was to be constructed on the lower reach of the stream to collect wastewaters in the lower reach basin and transport them to a centralized wastewater treatment plant.
An optimization study of the relationship between the sewerage interceptor and the sewage treatment plant on the upper reach was conducted. In this study, a comprehensive water pollution control plan, including the sewerage system, sewage treatment plant, and the use of treated wastewater as a water source for Majiagou Stream, was considered as a systematic problem in which many factors were taken into account. Cost-benefit analysis was carried out for both the sewage treatment plant and the interceptors by means of empirical regression equations and diagrams in which various curves showed the relationships between the important factors.
The Development of Operator Training in the Republic of South Africa
Authors: Cormack R. H. , Lewis N. J. , Barnard J. J. 
Published: May 2018

As part of the campaign to protect the Republic of South Africa's limited water resources, legislation has been drawn up stipulating the number and calibre of operators to be employed on a water care works. The registration and classification of both works and their operators will provide essential information for the refining and expansion of present training provisions.
Four new courses in water and wastewater treatment have been approved for inclusion in the National Technical Certificate system.
A preliminary training strategy is outlined and some anticipated improvements and modifications to be made in the years ahead are given.
Sewage Sludge Disposal: Current and Future Options
Authors: Bruce A. M. , Davis R. D. 
Published: May 2018

Sewage sludge is an inevitable product of all conventional sewage treatment processes. Disposal of sludge in an economic and environmentally-acceptable manner is becoming generally more difficult. Sludge quantities are rising and disposal options decreasing. Disposal will increasingly require positive and careful management. There are four basic destinations for sludge - agriculture, other types of land, the sea or minor outlets. Treatment methods are available for the production of nine basic types of end-product to suit particular disposal requirements. The new EC Directive will regulate sludge to agriculture and will require that all sludge to farmland is treated unless it is immediately buried under the soil.
Sludge to agriculture (grassland or arable) is subject to soil metal limits and to the need to minimise the risk of disease transmission. Sludge to landfill is subject to increasing constraints, particularly on physical stability. Sludge to sea is still practised by the UK but is closely controlled by Government licence and a requirement for monitoring. Minor outlets such as oil production, protein extraction etc are only at the experimental level. A computer program (WISDOM) provides a means of evaluating the short/long-term viability of alternative treatment and disposal options to identify the most economic and environmentally-acceptable strategy on an objective basis.
Optimisation of Aeration Efficiency: A Design Procedure for Secondary Treatment Using a Hybrid Aeration System
Authors: Thomas V. K. , Chambers B. , Dunn W. 
Published: May 2018

The fine-bubble diffused air (FBDA) system of aeration is most efficiently operated in low rate activated sludge systems. The aeration technique is, however, subject to poor oxygen transfer efficiency and diffuser clogging under increased loading conditions such as are experienced close to the tank inlet in plug-flow systems. Mechanical, surface aeration systems, though apparently less efficient, do not suffer from these disadvantages. The ideal aeration tank configuration, for optimum aeration efficiency is therefore:–inlet anoxic zone–completely mixed surface aerated zone–plug-flow, fine-bubble diffused air zone with tapered aeration–clarification tanks.
An overall aeration efficiency of 1.5-2.0 kg/kwh is predicted for nitrifying systems, together with an increased diffuser lifetime compared to a conventional FBDA tank. The design procedure is illustrated using parameters for a large UK works. Despite greater civil costs, the reduced running costs and NPC of the hybrid system make it an attractive option when compared to a plug-flow FBDA system or a conventional surface aeration plant.
Phosphatase Activity of Water as a Monitoring Parameter
Authors: Matavulj M. , Bokorov M. , Gajin S. , Gantar M. , Stojilković S. , Flint K. P. 
Published: May 2018

The biological monitoring of water saprobity and trophic degree primarily involves the study of qualitative and quantitative composition of organisms present in the water. Although relatively satisfactory as an indicator of the water's organic load, the counting of bacteria is often an unreliable parameter. Due to their polyenzymatic nature, which enables flexible adaptation to new and different physico-chemical conditions of their habitats, microorganisms respond quickly to trophic degree change, but faster by changing the level of their enzyme activity, than by changing the number of cells. On the basis of these findings, the enzyme activity of microbialaquatic biotopepopulations is suggested in recent literature as an additional indicator of the degree of organic load in the water.
The results obtained by investigation of the phosphatase activity in samples from natural and artificial water accumulations and flowing waters in Vojvodina Province, having different eutrophic degree, suggest the measurement of the level of water enzyme activity as an additional biochemical indicator of saprobity degree. At the same time, on the basis of long--term measurement of the water phosphatase activity, compared to classical categorizations based on qualitative and quantitative composition of organisms present in the water, classification of surface freshwater s into quality categories according to the level of enzyme (phosphatase) activity of water is proposed.
Physical Chemistry of the Interface between Attached Micro-Organisms and Their Support
Authors: Rouxhet P. G. , Mozes N. 
Published: May 2018

The thermodynamic approach of adhesion and DLVO theory are complementary to predict initial bacterial adhesion; the interplay between short- and long-range forces, respectively, may be due to surface roughness. Due to the influence of electrical double layer interactions, adhesion can be promoted by treatments leading to modification of the cell or support surface properties. Adhesion is influenced by cell-cell interactions, by the cpresence of polymer molecules on the surface and by the composition of the medium.
X-ray photoelectron spectroscopy can be applied to determine the elemental composition of the surface of microorganisms; some information on the chemical functions can also be obtained. The surface composition is related to physico-chemical properties which play a determining role in adhesion and flocculation, in particular the hydrophobicity and the zeta potential.
Biomass Retention in Advanced Anaerobic Reactors
Authors: Albagnac G. 
Published: May 2018

Recognition of the advantages of anaerobic wastewater treatment induced the development of high rate processes, i.e. reactors designed to allow an efficient treatment of even diluted streams. The performance of these advanced reactors is mainly dependent on the retention within the reactor of high bacterial concentrations. The prevailing mechanism is either the formation of bacterial aggregates with good settling characteristics, the development of methanogenic biolayers at the surface of inert carriers or both.
During the past decade information on the biology of methanogenic ecosystems became available at an increasing rate. From a practical point of view it can be stated that the biological conversion of organic compounds to methane is reasonably well understood. However the current knowledge on the aggregation and adhesion of methanogenic consortia remains very limited. In most cases reactor start-up procedures are rather long and appear to be more empirical than rational.
This paper is a brief presentation on the current knowledge of methanogenic aggregates and biofilms. The fundamental aspects of bacterial adhesion and the modelling of anaerobic biofilms growth are presented elsewhere.
Danish Experience with Emergent Hydrophyte Treatment Systems (EHTS) and Prospects in the Light of Future Requirements on Outlet Water Quality
Authors: Schierup H.-H. , Brix H. 
Published: May 2018

Since 1983 approximately 150 full-scale emergent hydrophyte based wastewater treatment plants (reed beds) have been constructed in Denmark to serve small wastewater producers. The development of purification performance for 21 plants representing different soil types, vegetation, and hydraulic loading rates has been recorded. Cleaning efficiencies were typically in the range of 60-80% reduction for BOD, 25-50% reduction for total nitrogen, and 20-40% reduction for total phosphorus. The mean effluent BOD, total nitrogen and total phosphorus concentrations of the reed beds were 19 ± 10, 22 ± 9 and 6.7 ± 3.2 mg/l (mean ± SD), respectively. Thus, the general Danish effluent standards of 8 mg/l for N and 1.5 mg/l for P for sewage plants greater than 5,000 PE cannot be met by the present realised design of EHTS. The main problem observed in most systems is a poor development of horizontal hydraulic conductivity in the soil which results in surface run-off.
Since the political demands for effluent quality will be more strict in the future, it is important to improve the performance of small decentral sewage treatment plants. On the basis of experiences from different types of macrophyte based and conventional low-technology wastewater treatment systems, a multi-stage system is suggested, consisting of sedimentation and sand filtration facilities followed by basins planted with emergent and submergent species of macrophytes and algal ponds.
Technology Assessment of Wastewater Treatment by Soil Infiltration Systems
Authors: Jenssen P. D. , Siegrist R. L. 
Published: May 2018

Infiltration of wastewater in buried soil infiltration systems has been promoted as a low cost, effective alternative for treatment and disposal of wastewater flows from commercial developments and small communities. Unlike many mechanical wastewater treatment systems, soil infiltration systems are subject to complex, far-reaching influences related to natural site conditions and the interaction of wastewater with a dynamic soil and ground water system. As a result, design and performance relationships are not always well defined and systems are often implemented based on local tradition and empiricism. Consequently there is a need for improvement of design criteria especially for large subsurface wastewater treatment systems.
Successful performance starts with thorough site investigations, where large scale infiltration tests or tracer studies might be needed. The hydraulic loading rate is a principal design parameter. An integrated approach for assessment of the hydraulic loading rate based on soil type and wastewater quality is suggested. In general, trench design should be preferred over beds, but rational criteria for selection of optimal geometry is lacking. Purification performance of subsurface wastewater infiltration systems is generally good. Estimates of purification on the basis of soil grain size, soil depth and loading rate can be given.