bluuebunny/crossref_metadata_2025 huggingface dataset:
Using Batch Reactors to Investigate Oxygen Consumption and Organics Decomposition in Drainage Systems with Attached Biofilm
Authors: Cao Y. S. , Alaerts G. J. , Hooijmans C. M. , Lubberding H. J.
Published: May 2018

Oxygen consumption and organics decomposition in drainage systems with attached biofilm were investigated using a batch reactor. In order to distinguish the relative contribution of suspended biomass and biofilm parallel experiments were performed. The reactors with low and high glucose concentrations simulated lightly polluted rivers and sewers. The dynamic behaviour was different for the systems dominated by biofilm and the systems with only suspended biomass due to different controlling mechanisms. The biofilm played a major role for the biodegradation only when the suspended biomass concentration was below a certain value. The ratio of wetted area on which biofilm grows over the water volume (WA/V) is closely correlated with the biofilm oxygen consumption rate, is also important to respirometer design. The relative contribution of the suspended biomass and biofilm was not sensitive to the change of initial glucose concentration.
A Study into the Removal of Iron from Ferruginous Ground Water Using Limestone Bed Filtration
Authors: Smith P. G. , Gaber A. , Hattab I. , Halim H. A.
Published: May 2018

A pilot plant consisting of limestone bed filtration and sand filtration has been built 15 km south of Cairo to serve about 400 people. The pilot plant consists of 3 limestone filter units operated in series and two sand filters. The limestone filters are 1.3 m × 1.3 m and have a media depth of 1.15 m, a liquid depth of 0.5 m plus 0.35 m free board. The pilot plant started operation in April 1991 and the initial operation of the pilot plant has shown that a packed limestone filter unit is a simple and cheap method of removing iron from ferruginous groundwater. The initial results have shown that when an inlet water of about 5 mg/l of iron is treated by one limestone filter and one sand filter at a flow rate of 0.9 m3/h, the treated water had an average iron concentration of 0.2 mg/l.
Waste-Water Treatment by Infiltration-Percolation on Sand: Results in Ben Sergao, Morocco
Authors: Guessab M. , Bize J. , Schwartzbrod J. , Mault A. , Morlot M. , Nivault N. , Schwartzbrod L.
Published: May 2018

Waste-water from Ben Sergao (Morocco) is treated by a process using infiltration on sand which includes an anaerobic lagoon (1500 m3) in which waste-water has a retention time of 1.4 days followed by 5 infiltration basins (1500 m2 each). Each basin comprises by a 2 meter thick sand dune layer. The basins are drained at their base through a network of gravel-embedded drains. Three 350 m3 batches are performed daily. These are received in 3 separate basins. Each basin receives one batch a day during 3 days and is then left to rest for 2 days before carrying out a new cycle.

It has been estimated that the treatment induced a decrease of 99.93 % for the fecal coliforms and 99.98 % for the fecal streptococci. Concerning the parasitology, neither nematode eggs nor cestode eggs were found in treated sewage even though their number in raw waste-water could be estimated respectively to be 139 and 75 per liter.

As for physicochemical parameters, no significant difference appears between raw and treated sewage for K, P and conductivity, but there is a very significant increase of parameters NO2 and NO3 and a very important decrease of COD and total suspended matter after treatment.

This treatment process seems to be very well adapted for the treatment of sewage and the reuse of treated water in rural areas.
The Role of Colloid Interactions in Solid-Liquid Separation
Authors: Gregory John
Published: May 2018

Forces between particles in water become especially important when the particles are in the colloidal size range (less than a few mm). To a first approximation inter-particle forces or colloid interactions are linearly dependent on particle size and they become stronger, relative to external forces, as particle size decreases. The separation of fine particles from water by processes such as coagulation, filtration and flotation can be crucially dependent on the manipulation of colloid interactions, usually to promote attachment of particles to each other or to surfaces.

The most important types of colloid interaction are briefly discussed. These include van der Waals forces, electrical interaction, hydration forces, hydrophobic interaction and effects associated with adsorbed polymers, such as steric repulsion and polymer bridging. These are all short-range interactions, which have little influence on the transport of particles but which can have a major effect on collision efficiencies and on the adhesion between particles. Some examples of solid-liquid separation processes in which colloid interactions are important are given.
Effects of Energy Input during Orthokinetic Aggregation on the Filterability of Generated Flocs
Authors: Bernhardt H. , Schell H.
Published: May 2018

The implications of energy input (G value) and energy input time (t value) as well as the Gt value (Camp number) resulting from the orthokinetic particle aggregation as part of the adsorption coagulation with charge neutralization were investigated in the laboratory using a direct filtration test apparatus with a stirred reactor developed by the Wahnbach Reservoir Association. The tests were carried out at a constant particle concentration. The water was flocculated with 5 mg/l Fe3+ at pH 6. In compliance with literature references, an optimum removal of turbid matter by means of this direct filtration apparatus was achieved at G values of around 40 s−1, t values of 15-30 min and within a Gt range between 30,000-60,000 which corresponds to a GCt range of 60-120 according to Ives. Only in this range are the G values of 30-50 s−1 compatible with t values.

By comparison it was shown that these values are in reasonable agreement with the results of our tests implemented on a full-scale direct filtration with two successive stirred reactors. Optimum direct filtration conditions were found to occur within a G range of 30-60 s−1, at t values of 15-20 min and within a Gt range between 15,000-40,000. From this comparison it can be concluded that results of hydrodynamic investigations into orthokinetic aggregation, which were obtained with the described laboratory floc filtration test apparatus, may well be applied as guide values in full-scale direct filtration processes.
Septic Tank Sludges: Accumulation Rate and Biochemical Characteristics
Authors: Philip H. , Maunoir S. , Rambaud A. , Philippi L. S.
Published: May 2018

A three year field and investigative study carried out on 33 individual sanitation systems showed that the frequency of septic tank emptying could be at least 5 years, corresponding to a sludge accumulation rate of 0.21/user.day. This value should be included in the calculation of septic tank sizing. Other data showed within a septic tank the methanogenesis is only effective after 2 years of operation. Thereby a septic tank should not be desludged before this period of time. At last, among all the physico-chemical parameters monitored to study the sludge quality, the best indicators of system failures were both the solids (TS and VS) and soluble matter (COD and some VFA). Then, biochemical study of septic tank sludge showed that the main hydrolytic enzymes (cellulase, phosphatase, protease, lipase and urease) are present in septic tank sludges and linked to the insoluble particles. Their solubilization with different solvents (buffers, surfactants…) showed each enzyme was linked in a different way.
Algae, Bubbles, Coagulants, and Dissolved Air Flotation
Authors: Edzwald J. K.
Published: May 2018

This paper like Ken Ives' PhD research comments upon algae and their removal from drinking water. Specifically, algal properties, difficulties in removing algae by conventional treatment, and dissolved air flotation (DAF) as a treatment method are emphasized. The stability of algal suspensions may be due to surface charge, hydrophilic effects, or steric effects. Coagulation is required as a pretreatment step in DAF to destabilize algal particles relative to the microbubbles, and thus ensure particle-bubble attachment The air supplied in DAF may be expressed fundamentally as mass, volume, and number concentrations of air bubbles. Calculations show high bubble volume concentrations compared to suspended particle volumes. The effectiveness of flotation is examined in terms of dimensionless products and compared to other particle processes. DAF is compared to settling for algal separation in experiments with DAF operating at higher overflow rates and smaller flocculation times. DAF produced clarified waters with lower turbidities and algal counts.
Status of Declining Rate Filtration Design
Authors: Cleasby John L.
Published: May 2018

Declining rate filtration is one of several flow control alternatives available for gravity filtration plants with four or more filters. Experimental and theoretical studies of declining rate filtration have provided the foundation for rational design procedures. This paper presents design procedures for estimating the filter system head needed for a declining rate filtration plant, and to predict the water level variations that will occur during operation. The paper also discusses the choice between inlet versus outlet rate limitation, the choice of type of rate limitation device, and the impact of operation of a declining rate filtration plant below full design load.
Advanced Treatment of Domestic Wastewater Using Sequencing Batch Reactor Activated Sludge Process
Authors: Imura M. , Suzuki E. , Kitao T. , Iwai S.
Published: May 2018

In order to apply a sequencing batch reactor activated sludge process to small scale treatment facilities, various experiments were conducted by manufacturing an experimental apparatus made of a factory-produced FRP cylinder transverse tank (Ø 2,500mm).

Results of the verification test conducted for one year by leading the wastewater discharged from apartment houses into the experimental apparatus were as follows.

Excellent performance was achieved without any addition of carbon source, irrespective of the organic compound concentration and the temperature of raw wastewater.

Organic substances, nitrogen and phosphorus were removed simultaneously. Due to the automated operation format, stable performance was obtained with only periodic maintenance. Though water depth of the experimental plant was shallow, effective sedimentation of activated sludge was continued during the experimental period. Regarding the aerobic and anaerobic process, nitrification and denitrification occurred smoothly.
Biological Nitrogen Removal under Low Temperature in a Membrane Separation Bioreactor
Authors: Chiemchaisri C. , Yamamoto K.
Published: May 2018

Biological nitrogen removal under low temperature in a membrane separation bioreactor for on-site domestic wastewater treatment was studied. The bioreactor was operated under intermittent aeration of a 180-minute operational cycle to achieve simultaneous nitrification and denitrification for nitrogen removal. During stepwise temperature decrease from 25°C to 5°C at every two weeks duration, nitrogen removal started to deteriorate as temperature dropped to 10°C. It decreased from more than 90% at 25°C to 20% at 5°C as a result of inhibition of nitrification at low temperature. However, increasing oxygen supply, i.e. increasing aeration time in operational cycle, could completely recover nitrification at 10°C. Nitrogen removal could be achieved by introducing non-aeration period after complete nitrification was obtained. Average nitrogen removal was 90 and 85% under 10 and 5°C respectively. The results indicated that sufficient oxygen transfer could be maintained in the membrane separation bioreactor even if the temperature was as low as 5°C. Analysis of respiratory quinone component of sludge suggested the decrease of strict aerobic bacteria percentage in mixed liquor during temperature decrease and increase of their percentage during the recovery of nitrification at 10°C. These changes could be related to the nitrification through the changes of oxygen transfer condition in the system. Insignificant difference of maximum volumetric nitrification rate obtained at 25 and 5°C probably suggests that there was not much difference in oxygen availability for nitrifying bacteria between both the temperatures once high and stable nitrogen removal was achieved.
Study on the Denitrification Ability of the Contact Aeration Process
Authors: Nakasone Hideo , Ozaki Masuo
Published: May 2018

Some reports (Hashimoto, Ozaki, and Matsunari, 1984) have indicated an approximately 80% T-N removal rate for contact aeration processes using small scale laboratory tests. However, actual small prototype sewage treatment plants have large variations of discharge and pollutant loads. Hence it will sometimes happen that the removal rates obtained at actual plants differ greatly from experimental plants (Nakasone and Ozaki, 1984), because they have the same shape but different surface areas of contact media which will have serious effects on denitrification. Hence the authors constructed three test plants which only differ in the surface area of the contact media and performed numerous experiments. As a result of three experiments, we understand that if we want to obtain a T-N concentration of less that 20mg/l in areal effluent during winter, a nitrification rate of more than 20% and NH+4-N areal loading of less than 3.0g/m2/day are necessary at the same time. It also became clear that the surface area of contact media will require at least 50m 2/m3. The phosphorus removal rate is about 60% without any dephosphorization process. Treatment results for other water quality parameters such as BOD, COD, SS, and pH were no problem at all.
Retrofitting and Operation of Small Extended Aeration Plants for Advanced Treatment – Some Experiences in Japan
Authors: Moriyama K. , Takahashi M. , Harada Y.
Published: May 2018

Some experiences concerning a retrofit design and operation for nutrients removal in small extended aeration plants are presented. In this study a new biological phosphorus removal process as well as a biological nitrogen removal process based on a sequential oxic-anoxic-oxic process is investigated. The denitrification in the first oxic zone has a high removing effect for nitrogen, and the oxidation reduction potential (ORP) value and dissolved oxygen (DO) concentration are useful indexes to maintain the optimum conditions of the first oxic zone for simultaneous denitrification. It is verified that the simultaneous denitrification can alleviate the alkalinity deficit problem against full nitrification by a stoichiometric analysis of alkalinity throughout the entire process. Additionally, a biological phosphorus removal process which uses a sludge blanket zone of secondary settling tank for phosphorus release is proposed.
Effect of Pre-Ozonation on Removal of Organic Matter during Water Treatment Plant Operations
Authors: Edwards Marc , Boller Markus , Benjamin Mark M.
Published: May 2018

Pre-ozonation altered removal of organic matter during bench or full-scale water treatment through two main effects. First, pre-ozonation directly removed organic matter by mineralization, volatilization and/or stripping reactions, improving removal in comparison to unozonated systems. On the other hand, pre-ozonation decreased the surface charge of floc formed after coagulation with hydrolyzable metal salts, hindering adsorptive removal of the anionic organic molecules by floc surfaces and/or inducing stabilized floc formation; changes that decrease removal in comparison to unozonated systems. The relative importance of the two effects determined whether pre-ozonation enhanced or hindered removal of organic matter. In most water treatment plants pre-ozonation is predicted to have an adverse effect on physical removal of organic matter at ozone doses above about 0.7 mg O3/mg TOC, while enhanced removal may occur if relatively high concentrations of volatile organic matter are present. In ancillary results, pre-ozonation hindered turbidity removal and increased the concentration of coagulant metal residuals in finished drinking water at low coagulant doses.
Laboratory and Full-Scale Plant Studies of Permanganate Oxidation as an Aid in Coagulation
Authors: Ma Jun , Li Guibai
Published: May 2018

Standard jar tests and full-scale plant studies were conducted to evaluate the effectiveness of permanganate preoxidation as an aid to coagulation-flocculation of surface waters. The results of the Jar tests demonstrated that permanganate preoxidation obviously enhanced the coagulation-flocculation of the studied surface waters. Through full-scale plant studies, the positive effects of permanganate assistance in coagulation-flocculation of surface raters were confirmed by the turbidity reduction of about 4~11 FTU at permanganate dosages of 1~2 mg/L. It was observed that the size of flocs in the reaction tank became bigger if the water was preoxidized with permanganate, lowering the polyaluminium chloride (PAC) consumption by about 36%. In addition. the effectiveness of prechlorination and permanganate preoxidation on assisting in coagulation-flocculation were compared through full-scale studies at a water treatment plant using a shallow lake as its water source. showing that permanganate preoxidation was a more effective means to aid coagulation-flocculatlon.
The Fate of Dissolved Organics in Water Purification Processes Treating Polluted Raw Water
Authors: Yeh Hsuan-Hsien , Huang Winn-Jung
Published: May 2018

The main purpose of this study is to look into the fate of dissolved organics through conventional water treatment processes preceded by prechlorination with high dosage to treat polluted raw water. In addition to organic surrogate parameters analyses, organics were fractionated into humic acid, fulvic acid, hydrophilic-acid and -neutral-four fractions. The results showed that the removal of hydrophilic fraction organics were limited, and prechlorination probably transformed some organics from other fractions into hydrophilic-neutral fractions. Therefore although prechlorination with high dosage could facilitate the plant operation when treating polluted raw water, it probably had some adverse effect on dissolved organics removal.
Characterization of Submicrometre Colloids in Freshwaters: Evidence for Their Bridging by Organic Structures
Authors: Filella Montserrat , Buffle Jacques , Leppard Gary G.
Published: May 2018

Colloidal particles play an important role in the distribution of pollutants in natural aquatic systems because they may sorb significant quantities of both inorganic and organic substances due to their large surface areas relative to their masses. Currently, only a limited amount of data is available on particle number and size distributions of natural submicron particles, owing to the many problems involved in their experimental determination. In the present paper, experimental results on particle size distribution and characterization of submicron colloidal particles from two different natural water systems will be discussed and compared with theoretical predictions based on a classical coagulation/sedimentation model. This theoretical model is well suited to describe the behaviour of particles greater than 100 nm but fails to predict the existence of colloids smaller than this. The existence of such small colloids have been observed by high resolution TEM. They seem to be embedded in large organic matrices, and probably for this reason they have neither been detected by other experimental techniques nor predicted by classical coagulation models. Improvement of the measurement techniques currently available as well as development of the theory necessary to describe this type of colloid-organic matrix associations are therefore definitely needed.
Effects of Adsorbed Organic Matter on Size, Structure and Filterability of Iron Oxyhydroxide Flocs
Authors: Waite T. D. , Amal R. , Ngo H. , Vigneswaran S.
Published: May 2018

In this study, the effects of adsorbed fulvic acid, a naturallyoccurringorganic acid, on the aggregation and filtration of hematite particles are investigated. The study of aggregate structure shows that the fractal dimensions of hematite aggregates which are partially coated with fulvic acid molecules are higher than those obtained with no adsorbed fulvic acid. The high fractal dimensions are due to restructuring within the aggregates, which only occurred at low coverage by the organic acid. In the filtration experiments, high clean filter efficiency was obtained for particles with the net charge opposite to the filter media. During ripening period, however, the particle sizesplayed a more important role than the surface chargesParticles of a micron size seemed to have less capture efficiency during this period, since they are controlled neither by diffusion nor interception.
Removal of Dissolved Hydrophobic and Hydrophilic Organic Substances during Coagulation/Flocculation of Surface Waters
Authors: Croué J. P. , Lefebvre E. , Martin B. , Legube B.
Published: May 2018

Dissolved organic carbon (DOC) from raw and coagulated surface waters was fractionated at acidic pH using two superposed XAD 8 and XAD 4 resin columns, into three fractions : hydrophobic substances (i.e. humic substances) adsorbed on XAD 8, hydrophilic acids adsorbed on XAD 4 and “non-acid” hydrophilics which represent the organics contained in the final effluent. DOC of untreated waters was evenly split between the hydrophobic and hydrophilic fractions. The “non-acid” hydrophilics were generally as or slightly more abundant than the corresponding hydrophilic acids. For three of the six waters studied, DOC distribution was not modified after coagulation/clarification treatment. These waters also exhibited a low reduction in THMFP and TOXFP per unit of DOC after treatment. One water showed moderate change and two a significant change in DOC distribution. With the latter, a large decrease of their THMFP/DOC and/or TOXFP/DOC ratios was observed. As expected, the apparent molecular weight distributions(1000 daltons nominal membrane cutoff) have been shifted toward the low molecular weight fraction. Aluminum coagulation experiments were carried out on isolated humic, fulvic and hydrophilic acids. Humic acids were identified as the most reactive fraction, with a dramatical reduction of their THMFP/DOC and TOXFP/DOC ratios after coagulation. Fulvic and hydrophilic acids were found to react to the same extent with the coagulant, and showed comparable THMFP and TOXFP perunit of DOC before and/or after coagulation.
Removal of Soluble and Particulate Organic Material in Municipal Wastewater by a Chemical Flocculation and Biohlm Processes
Authors: Watanabe Y. , Kanemoto Y. , Takeda K. , Ohno H.
Published: May 2018

Since the major part of the contaminants in municipal wastewater is associated with particles, direct particle separation is an effective way of lowering the wastewater contaminant level. An additional biological oxidation is usually required to remove the residual soluble contaminants. This paper presents the experimental data on the chemical treatment of municipal wastewater by the Jet Mixed Separator(JMS) which can be used as a unit process for physico-chemical treatment. As simultaneous flocculation and sedimentation occurred, the JMS effluent concentration of phosphorus and suspended solids was low in a hydraulic retention time of less than 1 hour. The removal efficiency of TOC associated with particles with a diameter of more than 0.1 µm was also high. The JMS effluent was treated using an upgraded Rotating Biological Contactor to remove the residual contaminants due to the surface adsorption of particulate contaminants and the biological oxidation of soluble organics and ammonia nitrogen. The performance of the combined system of JMS and RBC was very high in producing the effluent with very low concentrations of TOC, phosphorous and suspended solids in a hydraulic retention time of less than 2 hours.
Settling and Coagulation of Slender Type Diatoms
Authors: Konno H.
Published: May 2018

A slender type diatom is observed. The settling behavior and surface electrostatic situation of the diatom are discussed through the consideration of physiological activity and observation by SEM. By considering the settling behavior, one side of slender type diatoms such as Nitzschia and Synedra is heavier than the other side. The settling velocity is related to physiological condition of algae, for example the settling velocity in the endogeny phase is faster than it is in the logarithmic growth phase. The surface charging of diatoms is increased (more negative) by the existence of mucous algal borne substances at the surface of diatoms. It influences the neutralization. Aluminium hydroxide adsorbs at some specified points on the surface of diatoms, then the area covered aluminium hydroxide is spread. It is related to floc formation ability of the diatoms by bridging action.
Advances in Photometric Dispersion Analyzer with Dual Wavelength Light
Authors: Ohto Tokio , Zaitsu Yasushi , Matsui Yoshihiko , Tambo Norihito
Published: May 2018

A new dual-wavelength photometric dispersion analyzer is described which can be applied in the monitoring of coagulation/flocculation processes.
Comparison of Lime and Alum Treatment of Municipal Wastewater
Authors: Caceres Luis
Published: May 2018

The performance of lime alum as coagulants in municipal wastewater treatment are examined.
A New Method for the Identification of Infiltration Waters in Sanitary Flows
Authors: Verbanck M. A.
Published: May 2018

Extraneous clear water infiltration can significantly distort the operation and control of sewer systems. A method using the borate components dissolved in domestic sewage is outlined which enables the scale of any such problems to be well specified.
Potential Inaccuracy of Microbiological Counts from Routine Water Samples
Authors: Tillett Hilary E.
Published: May 2018

The procedures for estimating numbers of organisms in water lead potentially to large inaccuracies. Routine microbiological sampling is an important component of monitoring source waters for drinking supplies and recreational waters. The results should be interpreted with awareness that each result is liable to two sorts of error, even when correct procedures are followed. Firstly, there is sampling error due to variation over time in microbial density at the place of sampling and, secondly, statistical inaccuracies introduced by laboratory methods. Some of the errors can be measured or estimated, especially those in the second category.

Pre-dilution of a sample, which is unavoidable with heavily contaminated waters, can affect results by chance. For example, if 10 organisms are found after a 100-fold dilution then the estimated count for the original sample would be 1000 with 95% confidence intervals of 482 - 1834. If a presumptive count is followed up with confirmatory procedures which involve sampling then another imprecision is introduced. For example, if a presumptive colony count of 25 is checked by confirmatory tests on only 5 colonies then, if 4 of the 5 confirm, the 95% confidence for the final count would be 8 - 24. Although statistical confidence intervals from the combination of such laboratory procedures could be calculated they have little practical value and could cause confusion. An investigator who receives a report in the format of an organism count which is qualified by a 95% confidence interval might wrongly attribute that range to the source water.

Variation at the water source is usually much greater than the errors introduced by proper laboratory procedures. This sample ‘error' can be estimated only by replicate sampling. All sources of error should be considered when the quality of the water is assessed. Decisions about whether the water meets a particular Standard might be better made, from a statistical point of view, by assessing multiple samples rather than concentrating on single counts from very small volumes of water.
Detection of Salmonella in Shellfish Grown in Polluted Seawater
Authors: Kfir R. , Burger J. S. , Idema G. K.
Published: May 2018

Three bays along the South African coast were studied for the presence of Salmonella spp in seawater, effluent and stormwater discharges into the bays and in shellfish harvested at the same sites. The microbial quality of water and shellfish samples was studied using faecal coliforms and enterococci as indicators of pollution. A combination of Rappaport-Vassiliadis enrichment broth and bismuth sulphite agar was found to provide the best enumeration method for Salmonella spp in samples from a wide range of origins. A poor relationship between levels of indicator organisms and the presence of Salmonella spp was observed at both low and high densities of indicators. A correlation between the presence of Salmonella spp in shellfish and surrounding seawater was frequently found and in most instances Salmonella contamination could be traced to discharges in the vicinity. The findings of this study question the suitability of faecal coliform limits as guidelines for microbial quality of shellfish and shellfish harvesting grounds. Most seawater sites did not comply with the recommended indicator limits. Salmonella spp were detected in seawater and shellfish samples which were free of faecal coliforms.
Comparison of Methods for Recovery of Cryptosporidium from Water
Authors: Whitmore T. N. , Carrington E. G.
Published: May 2018

Methods were evaluated for the recovery of Cryptosporidium oocysts from water. Various types of cartridge filter were tested but proved to be inferior to the standard Cuno Micro-Wynd filter. Laboratory scale sand columns were also evaluated. The retention within the column material was satisfactory at low flow rates. However, the system was judged inadequate for monitoring because of the poor retention of oocysts within the column matrix at realistic flow rates. The continuous flow centrifuges tested were shown not to be capable of yielding satisfactory recoveries, although it is considered more refined machines currently available may warrant investigation. The vortex-flow filtration technique using the Membrex Benchmark device gave fairly consistent recoveries of 30-40%. However, the comparatively long process times would militate against the use of this device for monitoring purposes. A cross-flow filtration module was evaluated and gave relatively good recoveries (approximately 40-80%) at moderately high flow rates (0.9-1.01/min) from clean water samples spiked with Cryptosporidium oocysts.
A Comparison of Methods for Extracting Amplifiable Giardia DNA from Various Environmental Samples
Authors: Rodgers Mark R. , Bernardino Cathy M. , Jakubowski Walter
Published: May 2018

Human gastrointestinal illness due to Giardia duodenalis infection continues to be a public health problem. The ability to detect Giardia cysts is important in assessing the public health risk associated with environmental contamination. The low concentration of cysts in natural waters makes the use of the polymerase chain reaction (PCR) desirable in DNA probe-based detection methods. To date, amplification of DNA in environmental samples has been difficult to achieve. Humic compounds and/or other PCR inhibitors co-extract with nucleic acids, interfering with the polymerase reaction and lowering sensitivity. All of our attempts to separate humic compounds from DNA were unsuccessful. A substantial increase in the magnesium concentration in the reaction alleviated some of the inhibition, indicating that humics interfere by chelation of magnesium. PCR inhibition with environmental samples is most likely caused by a variety of contaminants.
The Effect of Ozone on the Viability of Cryptosporidium parvum Oocysts and a Comparison of Experimental Methods
Authors: Parker J. F. W. , Greaves G. F. , Smith H. V.
Published: May 2018

Cryptosporidium parvum oocysts were exposed to ozone using two experimental systems. The first method involved producing residual concentrations of 1, 3 and 5 mg/L of ozone in 500 ml of water in a Drechsel gas bottle, which was then inoculated with oocysts. The second method involved inoculating 7 L of water with oocysts and then applying a constant dose of 1, 3 and 5 mg/L of ozone, circulating the water in a contactor system. Viability was assessed by the inclusion/exclusion of fluorogenic vital dyes. Comparison of these two methods showed that the second method was considerably more successful at reducing oocyst viability than the first method. Experiments performed at an increased temperature using method one indicated that temperature was an influencing factor on oocyst inactivation by ozone treatment.
Application of the PCR Technique to the Detection of Hepatitis a Virus in the Environment
Authors: Divizia M. , Morace G. , Gabrieli R. , Pisani G. , Panà A.
Published: May 2018

Rapid, sensitive and specific teciiniques are needed to detect Hepatitis A virus in environmental samples. We have applied the method of Jansen et al. to concentrate river samples. In the analysis of 13 samples only two proved to be positive using the Elisa method (15.3%). Three samples were positive on cell culture (23%). The hybridization test resulted in 38.4% positive samples compared to the 67% obtained using the PCR method.

The PCR showed the highest sensibility when compared to the traditional methods (cell culture and Elisa) and the differences were statistically significant. The difference between hybridization test and PCR was not statistically significant.
The Use of Monoclonal Antibodies for the Detection of Faecal Bacteria in Water
Authors: Kfir R. , du Preez M. , Genthe B.
Published: May 2018

Monoclonal antibodies (MAbs) against heat-killed Escherichia coli and Klebsiella oxytoca originating from wastewater effluent were raised in BALB/C mice. The fusion was highly successful and three hybridomas cloned were selected to study the affinity and specificity pattern of the MAbs. The MAbs were found to react equally well with heat-killed and live bacteria when tested against their original immunogens. The MAbs showed lower specificity towards environmentally isolated faecal bacteria than a pure bacterial strain grown in the laboratory. A commercially obtained MAb showed the same specificity pattern.
Assessment of Staphylococcus Bacteria in Hawaii's Marine Recreational Waters
Authors: Charoenca Naowarut , Fujioka Roger S.
Published: May 2018

Several media to specifically recover staphylococcus from marine recreational waters in Hawaii were evaluated. The membrane filtration method using Vogel-Johnson and Tellurite Glycine Agar media supplemented with 0.005% sodium azide were shown to quantitatively recover total staphylococcus and S. aureus from marine recreational waters. Beaches in Hawaii were determined to contain high or low concentrations of staphylococci based on Favero's proposed standard of 100 staphylococci/100 ml as the maximum allowable concentration. Statistical analysis of the data showed that levels of total staphylococci were significantly correlated with that of S. aureus and with swimmer density. Staphylococci were recovered from beach waters throughout the day, including evening hours, indicating the stability of these bacteria in marine waters. Moreover, the antibiotic sensitivity patterns and phage types of S. aureus isolates from marine waters and from clinical human skin cultures were similar. These results support the hypothesis that recreational waters can serve as vehicles for the transmission of staphylococcal skin infections.
Disinfection of Human Enteric Viruses in Water by Copper: Silver and Reduced Levels of Chlorine
Authors: Bosch Albert , Díez José M. , Xavier Abad F.
Published: May 2018

Electrolytically generated copper: silver ions were evaluated in combination with low levels of chlorine for their ability to reduce the infectivity of hepatitis A virus, human rotavirus, adenovirus and poliovirus seeded in well and tap water. Overall, hepatitis A virus and rotavirus showed less than 2.6 log10 titre reduction for concentrations of 1 mg/l of free chlorine. For free chlorine concentrations of 0.5 mg/l or lower, with or without copper: silver ions, both of these viral strains suffered little inactivation. Poliovirus showed more than 4 log10 titre reduction in the presence of copper: silver combined with 0.5 mg/l of free chlorine, or 1 mg/l of free chlorine alone. Copper: silver ions (700:70 µg/l) reduced the infectivity of poliovirus. Although adenovirus was more efficiently inactivated than rotavirus or hepatitis A virus, it persisted longer than poliovirus under the same treatments, and its infectivity was never completely removed. The addition of copper: silver ions to reduce the levels of free chlorine do not ensure the total elimination of viral pathogens from water systems.
Preliminary Characterisation and Proposal of Microbiological Quality Standard of Sand Beaches
Authors: Mendes B. , Nascimento M. J. , Oliveira J. S.
Published: May 2018

The control of environmental quality of literal areas in EEC is mainly concerned with the microbiological quality of water (direct and indirect contact). Data concerning the microbiological quality of sand in different beaches of Portugal (three main coastal areas) are presented. Based on those results, data available In the literature and epidemiological information, a preliminary guideline criterion for the microbiological control of sand is proposed, to complete criteria used in “Blue Flag” distinction, accorded to high environmental quality beaches.
Determining Tradeoffs Between Water Quality and Profitability in Agricultural Production: Implications for Nonpoint Source Pollution Policy
Authors: Contant C. K. , Duffy M. D. , Holub M. A.
Published: May 2018

Agricultural nonpoint sources of water pollution have received increased attention over the past decade as routine monitoring has indicated the presence of contamination in both surface and ground waters. In Iowa (as well as other states), policy makers have debated the effectiveness of alternative policy mechanisms to control these agricultural pollution sources. In this study, we investigate both the water quality and farm profitability impacts of four policy options: regulation, taxation, intensive technical assistance including cost sharing, and research and education. Simulations of water quality and profitability impacts are run for a sample of farm fields in Iowa. Summarized results identify both the range of impacts from a particular policy and the tradeoffs between improvements in water quality and declines in farm profitability within and between policies. Results indicate that impacts differ across policy options and by location; however, improvements to both water quality and profitability can be achieved with some of these policies. These findings suggest that agricultural nonpoint source pollution policies can improve water quality without significant cost to farmers or statewide residents.
Market and Bargaining Approaches to Nonpoint Source Pollution Abatement Problems
Authors: Netusil Noelwah R. , Braden John B.
Published: May 2018

The ability of a market type mechanism to significantly reduce the compliance costs of current state and national erosion standards is investigated. The ability of such an institution when applied to a recursively produced pollutant such as sediment from agricultural land is, however, extremely sensitive to the order in which contracts are executed. The gain-ranked order of contracting is found to result in a larger reduction in costs than the mean cost reduction calculated under a random order of contracting. The degree to which actual contracting more closely corresponds to the random or gain-ranked order is, therefore, of crucial importance given the desirability of achieving a sediment load at the least cost possible.
The Investigation of Source Area Controls for the Treatment of Urban Stormwater Toxicants
Authors: Pitt R. , Lalor M. , Field R. , Brown M.
Published: May 2018

This paper summarizes some of the information obtained during research projects sponsored and directed by the U.S. Environmental Protection Agency's (EPA) Storm and Combined Sewer Research Program. The first phase of the project investigated typical toxicant concentrations in stormwater, the origins of the toxicants, and rain and land-use factors that influenced the toxicant concentrations. All metals investigated were found in all samples, including most filtered sample fractions. Thirteen of the base-neutral and pesticide organic compounds were found in at least ten percent of the samples. The most frequently detected organics were 1,3-dichlorobenzene (maximum concentration of 120 µg/l) and fluoranthene (maximum concentration of 130 µg/l). Both of these compounds were detected in 23 percent of the samples.

The second phase of the project investigated the control of stormwater toxicants (measured using the Microtox® screening test) through treatment unit processes. The benefits of the treatment processes varied for different samples. However, some of the treatment processes consistently provided the greatest benefits. The most beneficial treatment tests included settling for at least 24 hours (generally 40-90% reductions), screening through at least 40 µm screens (20-70% reductions), and aeration and/or photo-degradation for at least 24 hours (up to 80% reductions).

The current project phase, which is just beginning, is testing a prototype treatment device that would be useful for controlling runoff from automobile service facilities, probably the most widespread and significant toxicant source in urban areas. This device is also intended for pretreatment before infiltration of source area runoff from other areas.
Rainwater Quality from Different Roof Catchments
Authors: Thomas P. R. , Greene G. R.
Published: May 2018

A water quality analysis of rainwater collected from different roof catchments in rural, urban and industrial areas was conducted to determine its suitability for domestic purposes. Examination of the collected rainwater samples indicated that the bacterial quality was poor, and the physical and chemical qualities varied between each area and between each site. Rainwater from industrial area roof catchments had lead concentrations averaging two-fold higher than the WHO drinking water guidelines and also had high levels of turbidity, suspended solids and zinc. Water collected from rural area roof catchments had a higher concentration of nitrates and a slightly higher pH. Although lead was detected in urban area roof catchments, concentrations were not as high as the concentrations in the industrial area. The different roof types had an influence on the rainwater quality with zinc concentrations higher in galvanised iron roof catchments, while pH, conductivity and turbidity levels were higher in concrete tile roof catchments. The pollution of rainwater collected from roof catchments was mainly due to the diffused pollution from atmospheric deposition, and the number of dry days preceding a rainfall event affected the collected rainwater quality.
Groundwater Monitoring Network Design Using Minimum Well Density
Authors: Grabow G. L. , Mote C. R. , Sanders W. L. , L Smoot J. , Yoder D. C.
Published: May 2018

Limited resources for groundwater quality monitoring projects demand definition of groundwater contaminant plumes with a minimum number of sampling wells. The relationship between loss of information (or plume definition error) and degree of reduction in the number of sampling wells has been investigated by the authors. A proprietary sampling design product (E4) was used to select variably sized subsets of sampling wells from two existing natural gradient tracer tests. The tracer plume defined by data from each subset of wells was compared to the plume defined by data from the full set of wells. Differences between each subset plume and its corresponding full set plume were quantified and used to generate an error versus sampling density and time since tracer introduction function. Combined analysis of three sampling events from one tracer test and two from another revealed that the number of wells used for four of the events could have been reduced with minimal loss in contaminant plume definition. This suggests that E4 may be applied in the design of groundwater monitoring well networks.
Mobility of Some Heavy Metals in Soil-Plant Systems Studied on Soil Monoliths
Authors: Németh T. , Molnár E. , Csillag J. , Bujtás K. , Lukács A. , Pártay G. , Fehér J. , van Genuchten M. Th.
Published: May 2018

The soil can act as a natural buffer by retaining toxic materials present in municipal and industrial wastes and sewage sludges. Countries of Eastern Europe currently have a limited industrial infrastructure for recycling wastes. One of the most rational and economic ways for these countries to dispose of their waste waters and sludges is to apply them to agricultural fields, thereby utilizing also their nutrient content. A U.S.-Hungarian research project was recently started with the aim of studying the fate and transport of selected heavy metals in the soil profile of cropped undisturbed soil monoliths. Preliminary experiments were carried out to study the adsorption-desorption processes of these chemicals on disturbed soil samples, and to investigate the plant-availability of different metal forms. Concentrations of Zn, Pb, Cr and Cd in the soil solution were found to decrease with increasing soil moisture content and length of the adsorption period, both showing hyperbolic relationships. Lower soil moisture contents increased both the solution concentrations and the adsorbed concentrations of the elements. Release of adsorbed Zn and Cd was higher than that of Pb and Cr. Higher plant-availability of inorganic forms of Ni correlated with a higher phytotoxicity as compared to Ni applied in sewage sludge.
Impacts of Agricultural Nutrient Loading on Finnish Watercourses
Authors: Kauppi L. , Pietiläinen O.-P. , Knuuttila S.
Published: May 2018

Eutrophication of lakes, rivers and coastal waters is the main environmental problem caused by agriculture in Finland. Water quality of most Finnish watercourses is good or excellent, but in the intensively cultivated region of southern and western Finland the turbidity of water as well as algal blooms are a common problem. Generally, phosphorus is the limiting nutrient for primary production in Finnish lakes, but in eutrophic lakes and coastal waters the role of nitrogen becomes more important.

Nitrogen from agriculture enters the watercourses mainly in dissolved form. By contrast, most phosphorus is transported in association with small particles. According to bioassays the algal availability of this paniculate P is very low. Therefore, the eutrophying effect of agriculture can be estimated on the basis of dissolved nutrients. In shallow lakes, typical in agricultural regions, the release of dissolved P from the bottom sediment often induces the development of N2-fixing blue- green algal blooms. In some cases the internal load may exceed the external load. For the recovery of such a lake the introduction of better agricultural practices in the drainage basin has to be coupled with in-lake measures.