bluuebunny/crossref_metadata_2025 huggingface dataset:
The Carini Experimental Station for Wastewater Reuse in Agriculture – Preliminary Indications
Authors: Croce F. , Pollara J. R. , Oliveri R. L. , Torregrossa M. V. , Valentino L.
Published: May 2018

A two year experiment, to study the feasibility of wastewater reuse for a safe irrigation in the Sicilian context, has been initiated. Eight plots in two fields, totalling 629 m2, were planted with cowpeas (Vigna unguiculata L. Walp.), the irrigation water being supplied by a pilot plant treating 22 m3/day of municipal wastewater. The plant consists of an extended aeration biological system followed by rapid sand filtration and a choice of disinfection systems.

Analyses performed on all waters used in the experiment indicate that safe irrigation water, virtually pathogen-free, can be produced if careful operational techniques are adopted. Despite all possible care, however, soil samples taken throughout the growing season revealed cross-contamination problems, even in the plots irrigated with city water. Analyses were also performed on plants and beans collected over 17 successive harvests.
High Performance and N & P-Removable On-Site Domestic Waste Water Treatment System by Multi-Soil-Layering Method
Authors: Wakatsuki T. , Esumi H. , Omura S.
Published: May 2018

Multi-Soil-Layering (MSL) method was applied to make appropriate, but high performance and N & P-removable, on-site domestic waste water treatment system. The MSL soil unit is composed from soil layer mixed with 10∼25% of metal iron and pelletized jute. The MSL units were piled in a brick pattern at 5cm vertical and 10cm horizontal distance, which were surrounded by layers of Zeolite. Air can be supplied through porous pipes installed at adequate depths of the MSL system. The systems were tested using model houses. The waste waters, which were pretreated by septic tank to the level of SS 29-75, BOD 42-116, COD 32-56, T-N 29-86, and T-P 6-11 mg−l−1 respectively, could be treated at the rate of 100-850 1·m−2·d−1 without significant clogging. The mean concentrations of treated waters were SS 15, BOD 8.7, COD 11, T-N 6.8, and T-P 0.86 mg·1−1 respectively. Zeolite layers and brick pattern prevent clogging. Metal iron and jute pellets were effective to remove Phosphate and Nitrate. Intensive aeration assists decomposition of BOD, COD, and SS as well as nitrification, but decreases denitrif ication and phosphate fixation. The degree of purification could be controlled by setting adequate aeration.
Channelling in Batch Thickening
Authors: Aarne Vesilind P. , Jones Gregary N.
Published: May 2018

Channelling, which occurs during the batch thickening of concentrated slurries, allows water to escape the settling slurry at a high rate, thus increasing the interface settling velocity. This research shows that the upper layers of the settling column are progressively diluted and that the channel zone occurs at the interface between the diluted slurry and the slurry in compression. As the solids in the lower sections of the column compress and expel water, this water escapes by means of the channels.
Management of Dairy Waste: A Low Cost Treatment System Using Phosphorus-Adsorbing Materials
Authors: Masters B. K.
Published: May 2018

Dairy wastes are a source of nutrient pollution of surface and ground waters in high rainfall areas of south west Western Australia. Many of the state's 546 dairies are sited over soils that are either sandy, leading to pollution of ground waters, or clayey, causing reductions in surface water quality. Awareness of the environmental implications of their activities is motivating dairy farmers to join Land Conservation District Committees, where water quality improvement is a primary goal. A low cost treatment system has been designed to reduce the water pollution potential of dairy waste. It incorporates three stages: a sump in which anaerobic digestion occurs; an aerobic vegetated filter with a base of permeable phosphorus-absorbing material; and an irrigated plantation or crop using water that has passed through the system. This paper describes the theoretical background to the design.
Characterization of Activated Sludge and Conditioning with Cationic Polyelectrolytes
Authors: Eriksson L. , Alm B.
Published: May 2018

Three cationic polyelectrolytes with different charge densities were used to condition activated sludge samples from a municipal plant during a period when the sludge characteristics changed strongly. Initially the sludge had high residual turbidity after sedimentation, high filtration resistance, low floc strength and high amounts of extractable extracellular polymers (ECP). These problems could be related to the snow melting that was going on. When that ceased the sludge recovered as shown by decreased residual turbidity, filtration resistance and amount of extractable ECP and increased floc strength.

The polyelectrolytes with 40 and 100 % charge density gave good and similar filterabilities during the whole investigation period. With the 10 % charged polymer the filtration resistance was generally higher and especially so during the snow melting period. The reason is that low charge density polymers flocculate with a bridging mechanism. This gives a flexible floc structure which allows the formation of dense filter cakes and also to some extent preserves the original structure. High charge density polymers give closer contacts between the particles and thus a more inflexible and open structure which is favourable in filtration.
Rapid Mixing in Sludge Conditioning with Polymers
Authors: Langer S. J. , Klute R.
Published: May 2018

The effect of mixing in sludge conditioning with polymers on the sludge dewaterability has been investigated by many researchers. What has been lacking so far are experimental data from a systematic variation of the rapid-mix conditions. Thus an experimental set-up was chosen to evaluate the effect of mixing by conditioning wastewater sludges in continuous mode rather than in batch-mode.

The results show that the rapid-mix conditions have a strong effect on sludge dewaterability. Variations in the rotational speed of in-line stirring devices revealed that intense mixing is mandatory when conditioning anaerobically digested sludges. The results indicate that during a period of one second after polymer addition, mixing with maximum intensity (rotational speeds up to 1700 rpm) at the proper polymer dose does not lead to a deterioration in dewaterability. These findings could be confirmed by experiments with sludges from different treatment plants. The investigations with the different sludges revealed differences in the energy required for mixing in order to obtain optimal dewaterability. The mixing requirement is, in addition, strongly dependent on the polymer dose. High polymer doses are less sensitive to mixing, while at low doses, intense mixing becomes important

Attempts have been made to describe the observed phenomena by considering the sludge rheology and the changes in rheology that take place in the reaction with the polymer.
Evaluation of the Impact of Return Flows on the Operation of a Wastewater Treatment Plant
Authors: Grulois P. , Bousseau A. , Blin E. , Fayoux C.
Published: May 2018

A systemic analysis of a wastewater treatment plant quickly reveals that return flows from the sludge treatment line affect the water treatment process. These return flows have a maximum value that is characteristic of a steady state of plant operation and the effects are detectable at several levels. It can, for example, influence the operation of the clarifier indicated by changes in the Sludge Volume Index, induce anaerobiosis in the separation works that stems from excess sludge production or decrease the dewatering of sludges. All these observations lead to the conclusion that the sludge treatment line should be designed that it could take up production overloads. It was also found that it is indispensible to monitor the water treatment line operation step by step in order to detect rapidly any drift of the operating parameters from their normal values.
Anaerobic Treatability of Olive Oil Mill Wastewater
Authors: Tsonis S. P. , Grigoropoulos S. G.
Published: May 2018

A study was undertaken to evaluate the anaerobic treatability of different types of olive oil mill wastewater, including raw waste (concentrated or diluted) and pretreated waste containing soluble organics only. Anaerobic treatment of concentrated raw waste in draw and fill digesters operating at organic loading levels up to 4 kg COD/m1·d effected 68-74% mean BOD5 and 78-81% mean COD removals, while treatment of diluted raw waste in the same type digesters fed at a hydraulic detention time of 8 d and organic loading levels up to 3.7 kg COD/m3·d resulted in 83-84% mean BOD5 and 75-77% mean COD removals. Anaerobic treatment of the soluble organics contained in mill wastewater in draw and fill digesters operating under simulated steady state conditions at hydraulic detention times 8-20 d and an organic loading level of 0.8 kg COD/m3·d achieved 72-88% mean BOD5 and 56-70% mean COD removals. The maximum attainable soluble organics removal was found in the range 77-79% for soluble COD and 92-95% for soluble BOD5.
Feed Characteristics and Digester Operative Conditions as Parameters Affecting the Rheology of Digested Municipal Solid Wastes
Authors: Battistoni P. , Fava G. , Stanzini C. , Cecchi F. , Bassetti A.
Published: May 2018

The rheology of pre-composted and fresh organic fractions of municipal solid wastes (OFMSW) anaerobically digested in thermophilic range of temperature and different operative conditions is presented. Rheological properties are strongly influenced by feed characteristics and the biodEgradation achieved. The metabolization of complex substrates has been invoked to explain different behaviours. A semiempirical model of plastic viscosity with total volatile solids, organic loading rate removed and specific gas production before feeding is proposed. The fluid behaviour of OFMSW sludges where complex substrates exert a determinant role, is outlined by thixotropy and temperature effect.
Fuzzy Control of an Anaerobic Digester for the Treatment of the Organic Fraction of Municipal Solid Waste (MSW)
Authors: Boscolo A. , Mangiavacchi C. , Drius F. , Rongione F. , Pavan P. , Cecchi F.
Published: May 2018

This paper deals with an application of the fuzzy approximate reasoning to the management and control of a pilot scale anaerobic digester. The organic fraction of MSW was used as substrate of the digester operating under semi-dry, thermophilic conditions. The fuzzy control actions suggested by the controller are taken on the basis of an emulation of expert reasoning instead of a mathematical representation of the digester behaviour. This approach is realized by capturing the expert's knowledge of the process through knowledge engineering methods. The controller performance was checked against the expert's behaviour for a set of experimental data. The experimentation has thus far proven that a controller for anaerobic reactors based on fuzzy logic is feasible and that the fuzzy approach provides a relatively simple description of human behaviour from different points of view.
A Mathematical Model of Volatile Fatty Acids (VFA) Production in a Plug-Flow Reactor Treating the Organic Fraction of Municipal Solid Waste (MSW)
Authors: Negri E. D. , Mata-Alvarez J. , Sans C. , Cecchi F.
Published: May 2018

A mathematical model of a plug-flow reactor with a fluid recycle has been elaborated to simulate the VFA production process treating the organic fraction of the municipal solid waste. An alternative hydrolytic reaction model (homogeneous - heterogeneous) is proposed. The effect of a possible methanization step is also considered. The effect of process parameters (solid retention time (SRT), pH, recycle ratio) on the reactor performance is analyzed for parameters based on fruit and vegetable waste. The sensitivity of the model to proposed parameters (suspended biomass and initial biomass concentration) is also evaluated. It is found that the reactor production is very sensitive to the system pH. At low SRT, the production of volatile fatty acids (VFA) is proportional to this parameter. As the SRT increases methanization can reduce the VFA production. The effect of the recycle is negligible for the system and operating conditions studied. The effect of suspended biomass and initial biomass concentration was found to be also negligible. For the system analyzed, the pH is a critical parameter and a plug-flow arrangement (without recycle) seems to be the more reasonable election.
Landfill Gas: From Environment to Energy
Authors: Nyns E.-J. , Gendebien A.
Published: May 2018

A survey was recently achieved, on behalf of the Commission of the European Communities, to scrutinise the state-of-the-art of landfill gas control and exploitation. The survey is divided into 8 parts After an Executive Summary, part I deals with the environmental impact of landfill gas and details 166 reported cases of landfill gas damages in uncontrolled landfills. The second one details the process of landfill gas generation and the technology of landfill gas control by its exploitation. The third part surveys the methodologies for monitoring landfill gas emissions for landfill gas potential evaluation and for safety. The fourth part deals with policies and legal aspects of landfill gas in the European Community and in the World. The fifth part estimates landfill gas potentials and overviews the economics of landfill gas control and exploitation, notably by the exhaustive assessment of 6 case studies. The sixth part gives the status of landfill gas exploitation in the European Community and in the World. The two final parts list utilities and references.
Influence of Codisposal of Municipal Solid Waste and Olive Vegetation Water on the Anaerobic Digestion of a Sanitary Landfill
Authors: Cossu R. , Blakey N. , Cannas P.
Published: May 2018

A research study was carried out aiming to investigate the possibility of treatment of vegetation water in a anaerobic digester like a sanitary landfill. This vegetation water originates from olive oil production. The results, obtained from lysimeters filled with Municipal Solid Waste, show very high gasification and reduction of the organic load of vegetation water, with no inhibitory effect on waste degradation processes providing the vegetation water is added to an active methanogenic system or buffering the landfill system during the acid phase. The inhibitory influence of compounds, like polyphenols, which can be present in vegetation water in large amounts, has been studied.
Enhanced Activity of Alkaline Phosphatases - Phytoplankton Response to Epilimnetic Phosphorus Depletion
Authors: Vrba J. , Komárkova J. , Vyhnálek V.
Published: May 2018

The stratified, eutrophic ůímov Reservoir (South Bohemia) receives a considerable input of phosphorus. However, phytoplankton development in the epilimnion has often been P-limited (<5 µg.1−1 of soluble reactive phosphorus) during spring and summer when algal maxima are observed. Alkaline phosphatase activity (APA) was measured in the epilimnion (0-2 m) using a fluorimetric method. The seasonal course of APA (range 6.7-726.7 nmol.1−1.h−1) roughly followed that of chlorophyll a (r2 = 0.45) in 1990. During algal blooms, a significant percentage of total APA was found in the 2.5-100 µ µm fraction containing most of the algae. Very similar relationships were found by a longitudinal sampling of the reservoir epilimnion during the spring phytoplankton bloom in 1991, despite high P concentrations in the reservoir's tributary. Hence, phytoplankton can be P-limited in the epilimnion, even in a eutrophic reservoir with a high input of P. This study shows that the phytoplankton community might adapt to phosphorus depletion by changing species composition and/or by increasing APA.
The Treatment of Saline Wastewater Using a Two-Stage Contact Oxidation Method
Authors: Li An , Guowei Gu
Published: May 2018

This paper introduces the treatment of saline organic wastewater using a two-stage contact oxidation method. The experiment was carried out to explore how several factors affect the results of the treatment such as salinity, organic loading and organic ingredients in influent. The experiment revealed the organic loading ranges within which the salinity had less effect on the treatment efficiencies when influent salinity was 25,000 ppm and 35,000 ppm respectively. Moreover there is a theoretical discussion on the effect of organic ingredients on the removal of organic substances from wastewater.
Uptake of Nitrogen and Phosphate, and Water Purification by Water Hyacinth Eichhornia Crassipes (Mart.) Solms
Authors: Aoyama Isao , Nishizaki Hisao
Published: May 2018

Water hyacinth (Eichhornia crassipes (Mart.) Solms) grows very vigorously and has a high content of nutrients. Cultivation experiments were conducted on water hyacinth to check whether it is worth using for water purification and to obtain guiding principles for the practical use of water hyacinth grown in natural water channels or ponds.

The average dry weight, nitrogen and phosphate content in the biomass were 5.0%, 2.5% and 0.57%, respectively. The growth rate of the water hyacinth was higher from May to June than in other seasons. The logarithmic regression equation between the growth rate (Y) and solar radiation (X) was expressed by Ln (Y) = 0.0042X-4.92 with a coefficient of correlation of 0.768. The relationship between the concentration of nutrients in water (X) and in water hyacinth (Y) is expressed by Y = Cmax.X/(Ks+X). The relationship between the relative growth rate and the concentration of nutrients was also expressed by the same type of equation. The relationship between a harvesting interval and the total yield of the water hyacinth within a given period was expressed by a mathematical model. It was made clear from the model that the shorter the harvesting interval was, the more the total yield of the crop increased.
Industrial Wastewater Treatment Using an Activated Algae-Reactor
Authors: Aziz M. A. , Ng W. J.
Published: May 2018

A laboratory investigation was carried out on the removal of organics, colour, toxic metals and nutrients from industrial wastewaters using an activated algae-reactor system. The preliminary investigation shows encouraging results on removal of such pollutants from the industrial wastewaters. In this paper, the authors present the results of their investigation and highlight the effectiveness of the activated algae-reactor system for treating industrial wastewaters as a means for alleviating the pollution of water bodies.
Algae Migration Characteristics in Fresh Water Red Tide
Authors: Wang Dunchun , Somiya Isao , Fujii Shigeo
Published: May 2018

To understand the algae migration characteristics in the fresh water red tide, we performed a field survey in the Shorenji Reservoir located in Nabari City, Japan. From the analysis of the field data, it is found that the patterns of vertical distributions of the indices representing biomass are very different in the morning and the afternoon. Since some water quality indices have reverse fluctuations between the surface and the bottom layer in respect of the time series changes and the total biomass of the vertical water column is relatively constant, it is concluded that vertical and daily biomass variation of red tide alga is caused by its daily migration, that is the movement from the bottom layer to the surface in the morning and the reverse movement in the afternoon.
Comparison of Legislation for Water Pollution Control in Asian Countries
Authors: Mino Takashi
Published: May 2018

Information on legislative and administrative water pollution control systems in ten Asian countries was collected through direct contact or mail correspondence with relevant government officials or engineers. Effluent concentration control is the most common system to control water pollution. Effluent standard values in the countries examined are compiled and the structural differences of the effluent control systems are discussed. Japan has relatively lenient standards, but because of its supporting measures for the implementation of the effluent standard system it has achieved satisfactory water pollution control.
Anaerobic Treatment of Domestic Sewage and Wastewater
Authors: Lettinga G. , de Man A. , van der Last A. R. M. , Wiegant W. , van Knippenberg K. , Frijns J. , van Buuren J. C. L.
Published: May 2018

Recent UASB-pilot plant and full scale experiences show that anaerobic pre-treatment is feasible for sewage and domestic wastewaters in tropical regions. This offers developing countries the unique opportunity to become completely self-sufficient in this respect. UASB-systems can be applied at very small and at very big scale, i.e. for off-site and (house and community) on-site treatment. Results obtained in pilot plant and full scale installations demonstrate that these systems are quite effective in removing and stabilizing organic pollutants at liquid detention times as low as 4 hrs, i.e. a BOD reduction up to 75-95 % can be achieved, while an almost complete treatment can be accomplished by combining the method with a small aerobic lagoon. Instead of consuming high grade energy, these systems produce energy. Moreover the excess sludge production is very low, while also the dewatering characteristics of the sludge are excellent.
Infiltration Percolation in France: 10 Years Experience
Authors: Brissaud F. , Lesavre J.
Published: May 2018

A survey was carried out during the late '80s over 7 infiltration percolation plants, serving populations ranging between 400 and 1700. With sand depths, hydraulic loads, influent COD and NTK concentrations respectively ranging from 0.6 to 0.2 m, 0.07 to 0.77m/day, 820 to 75 and 70 to 10 mg/l, and with different operating schedules, this set of plants displays a wide spectrum of infiltration percolation in use.

When plants are suitably designed, sized and operated, primary effluents oxidation is very effective and current EEC quality standards for wastewater treatment plant effluents are matched. Disinfection is poor, below the level expected from laboratory and pilot plant data. This is due to non-uniform spreading of the influents on the infiltration areas and exceedingly short circuits and short water detention times in the sand beds.

Based on a theoretical approach and on data obtained from these and many other plants, a sizing methodology is provided. Recommended improvements in the spreading technology, as well as in the plant design and management, should lead to more reliable oxidation and disinfection performance
Recent Development of Membrane Processes for Water and Waste Water Treatment
Authors: Ben Aim R. , Liu M. G. , Vigneswaran S.
Published: May 2018

Membranes are presently used at industrial scale for water and waste water treatment, but still for limited production. More knowledge of hydrodynamic phenomena has recently resulted in significant technical improvements (backflush, unsteady flow). However an experimental study performed at lab scale in a rotating membrane device has shown the complexity of the relationship between operating conditions, rejection and filtrate flux. The need for bettering the quality of the water (low turbidity) and waster water (disinfection) may be in favour of the development of membrane processes if efficient models allowing simultaneous optimization of quality and productivity are made available (as was done years ago for deep bed filtration).
Potential Use of Constructed Wetlands for Wastewater Treatment in Northern Environments
Authors: Jenssen P. D. , Mæhlum T. , Krogstad T.
Published: May 2018

Constructed wetlands consist of soil filled beds with aquatic plants. Wastewater is treated when flowing through these beds. It has been questioned if constructed wetlands will be able to operate when subjected to cold conditions in sub arctic regions. Experience from Norway indicates that significant biological activity occurs at temperatures between 0 and 5°C, and that high removal rates of nutrients and organic matter are achieved in ponds and soil amended with wastewater at these temperatures. Results from using constructed wetlands in Denmark, Sweden and North America show that winter performance is not significantly reduced as compared to other seasons, but in order to obtain high removal of organic matter and nitrogen in cold climates aerobic pretreatment is probably a prerequisite. Cold climates may also require careful installation of larger and deeper systems with a longer detention time. Results of 15 months operation of a Norwegian multi-stage constructed wetland pilot plant optimised for nutrient removal, show 55% nitrogen and 98% phosphorus removal. The large phosphorus removal is obtained by using sand with a high content of iron oxides and a fabricated porous medium that has a high phosphorus adsorption capacity. It remains to be seen if long term cost efficient phosphorus removal can be obtained in constructed wetlands. The results indicate that properly designed constructed wetlands can operate satisfactorily in a cold climate. When adequate design criteria are developed several possible applications exist for these simple low maintenance systems as main treatment system, or in conjunction with other treatment methods.
Sequencing Batch Reactors for Nutrient Removal at Small Wastewater Treatment Plants
Authors: Rusten Bjorn , Eliassen Helge
Published: May 2018

In order to optimize the sequencing batch reactor (SBR) process for nutrient removal at small wastewater treatment plants, a two year study was carried out at a treatment plant designed for 300 population equivalents. Different operating cycles, solids retention times (SRTs) and periods with co-precipitation were included in the test program. Based on the results, recommendations for achieving nitrification, denitrification and biological phosphorus removal were given. A suitable coagulant (and the optimum dosage) for co-precipitation was found as well.
Cold Climate Sequencing Batch Reactor Biological Phosphorus Removal – Results 1991-92
Authors: Marklund S.
Published: May 2018

The aeration tank in a small scale wastewater treatment plant was converted to a sequencing batch reactor (SBR) with a maximum volume of approx. 27 m3. The main purpose of this study was to examine low temperature biological phosphorus removal (BPR). The wastewater temperature varied during the study between 3 and 8°C, with a water temperature at or below 5°C during 7 months of the year.

The SBR unit has been in operation from the end of 1989, the study period discussed here covered July 1991 - December 1992. SBR cycle time was varied between 6 and 12 hours, giving a total daily treatment capacity of between 18 and 36 m3.

The influent biological oxygen demand - 7 days (BOD7) levels varied between 88 and 165 mg/l. Corresponding phosphorus levels were between 3.10 and 9.55 mg/l The mean effluent level of phosphorus was 1.57 mg/l and the BOD7 value was 23 mg/l. This gives a mean total phosphorus reduction of 74% and a BOD7 reduction of 81 %.

During the study, mean supernatant suspended solids (SS) levels were quite high, at around 36 mg/l. This high SS level contributed a major part of both outlet phosphorus as well as BOD7 value. Effluent soluble values for phosphorus and BOD7 were 0.79 mg/l and 9 mg/l.

The supernatant SS component of BOD7 and phosphorus increased at lower temperatures. It was not possible to reduce or balance this increase by increased cycle time or increased settling time within the maximum cycle time available (12 hours). Stable low supernatant phosphorus and BOD7 levels are thus to a large degree controlled by the effluent SS level. A maximum of 20 mg/l supernatant SS is necessary to reach target supernatant values of less than 1 mg/l of phosphorus and 15 mg/l of BOD7.
Fundamental Behavior of Humic Acid and Kaolin in Direct Sand Filtration of Simulated Natural Surface Water
Authors: Ebie K. , Amano S.
Published: May 2018

This article discusses the fundamental behavior of kaolin, humic acid, and aluminum in the primary coagulant PAC, which were included together or separately in three simulated natural surface waters, in direct sand filtration. According to the bench scale experiment, the treatment of water containing humic acid with or without kaolin was found to be much more complex than that of turbid waters. With the filtration of water containing both the materials, at most 31 % of humic acid was removed at a pH level of 7, and 78 % at a pH level of 5 corresponding to a suitable coagulation pH level, with the additions of 25 mg/l of PAC and 0.15 mg/l of an organic polymer. A strong correlation was also noted to exist between the behaviors of humic acid and aluminum.
Comparison of Polyferric Sulphate with Other Coagulants for the Removal of Algae and Algae-Derived Organic Matter
Authors: Jiang Jia-Qian , Graham Nigel J D. , Harward Clive
Published: May 2018

This paper is concerned with the performance of a relatively new form of metal-iron coagulant, Polyferric Sulphate (PFS), which has received very little research attention to date. Laboratory experiments have been undertaken in which the coagulation performance of PFS, Ferric sulphate, Aluminium sulphate and Poly aluminium chloride have been studied using ‘model' waters containing single cultures of algae (Anabaenaflos-aquae and Asterionetta formosa) and other ‘model' waters prepared by mixing aquatic humic substances with Asterionella formosa at different concentration ratios. Physico-chemical variables such as colloid charge, floc number concentration and size distribution, DOC concentration and turbidity, have been determined to quantify treatment performance. The performance of PFS was found to be superior to the other coagulants and this was believed to be due to the presence of more highly charged cation species. For all coagulants there was an approximate stoichiometry between coagulant dose and the dissolved organic carbon concentratioa
On the Types of Bond Developing between the Aluminium and Iron (III) Hydroxides and Organic Substances
Authors: Licskó István
Published: May 2018

During the coagulation-flocculation processes involved in the treatment of surface waters, dissolved organics are also incorporated into the aluminium and iron (III) hydroxide flocs. A part of the dissolved organics can thus be removed by simple solid-liquid phase separation techniques, like sedimentation, flotation, sand filtration. According to laboratory evidence, durable bonds between the coagulant, or the metal hydroxides thereof, develop only over the extremely short (a few seconds) period which elapses from the formation of the metal hydroxides to the intense aggregation of the metal hydroxide sols. The bonds between these latter and the organic substances are mainly of the hydrogen bridge type, but other secondary chemical bonds and adsorption are also involved. Owing to the chemical structure and relatively low concentration levels of the organic substances, direct valence chemical bonds between the coagulants or the metal hydroxides thereof and the organic substances develop to a slight extent only.
Real Time Control in Part of Copenhagen
Authors: Linde-Jensen Jørgen Jens
Published: May 2018

The application of real-time control to the sewer system in a district of Copenhagen is described. It enables the storage capacity of the sewer system to be better utilised, thus minimizing combined sewer overflow pollution.
DNA Probe Hybridization and PCR Detection of Cryptosporidium Compared to Immunofluorescence Assay
Authors: Johnson D. W. , Pieniazek N. J. , Rose J. B.
Published: May 2018

There is a need for the development of methods for the detection of Cryptosporidium in environmental samples. Two assays which detect the DNA of this parasite were developed and compared to the traditional method of detection, immunofluorescence assay (IFA). Oligonucleotide primers hybridizing to small subunit ribosomal RNA coding sequences were used in the polymerase chain reaction to develop highly specific detection of Cryptosporidium species. The PCR assay could detect about 20-100 oocyst equivalents in clean samples, but the sensitivity was reduced in some environmental samples. Detection based on direct hybridization of repetitive DNA probes from C. parvum was also accomplished, but the assay was not as sensitive as PCR or IFA and yielded false positive signals with environmental samples.
Diseases Associated with the use of Recreational Waters: Assessing Their Relationship to Microbiological Parameters
Authors: Cartwright R. Y.
Published: May 2018

The evidence for the link presumed to exist between feecal contamination of recreational waters and the diseases suffered by users of such waters is reassessed. For minor diseases the causes of the symptoms are not clearly established and it is concluded that more research is needed before preventative measures can be realistically devised.
Detection of Human Hepatitis a Virus in Environmental Water by an Antigen-Capture Polymerase Chain Reaction Method
Authors: Prévot J. , Dubrou S. , Maréchal J.
Published: May 2018

To detect hepatitis A virus (HAV) in environmental water samples, sensitive and specific methods are needed. An hemi-nested enzymatic amplification procedure was developed. When it was associated with an immuno-capture (IC) step, specificity and sensitivity were increased. The presence of a specific DNA fragment of 318 bp was detected by the analysis of the electrophoresis of the PGR products and confirmed on the autoradiogram of the Southern blot of the gel, using a labeled oligoprobe PAl selected in a very highly conserved region of the genome coding for the capsid protein VPl. The IC/PCR detected less than one infectious unit of virus in 75 µ1 sample. Eleven Seine River samples and two drinking water specimens were monitored by this assay. The IC/PCR brings a significant contribution for increasing our knowledge of the incidence of HAV on public health.
Chlorine Injury and the Comparative Performance of Colisure™, Colilert™ and Coliquik™ for the Enumeration of Coliform Bacteria and E. coli in Drinking Water
Authors: McFeters Gordon A. , Pyle Barry H. , Gillis Shaun J. , Acomb Carole J. , Ferrazza David
Published: May 2018

Several factors have stimulated interest in recently developed substrate specific media for the detection of coliform bacteria in water. This study compared the performance of Colisure™ (Millipore), ColiLert™ (Environetics) and ColiQuick™ (Hach) with accepted membrane filtration and MPN methodologies for the enumeration of total coliforms and E. coli in chlorinated water. The performance of all three media was compared, in MPN configuration, with LTB/MPN (confirmed) using a variety of drinking and source water samples, both with and without chlorination. The Cochran-Mantel-Haenszel test yielded statistical correlations between results obtained with each of the three new enzyme detection media and accepted reference methods for the detection of low numbers of total coliforms. Another series of tests compared the performance of Colisure with accepted methods (LTB/MPN confirmed with BGLB and EC-MUG) in the detection of total coliforms and E. coli in sewage-spiked samples simulating contaminated drinking water, using an USEPA/AWWA test protocol. The results demonstrated that Colisure detected these indicator bacteria with greater sensitivity than the accepted methods and that this difference increased between 24 and 28 hours of incubation. The results of this study collectively support the validity of the new enzyme detection method for the detection of low levels of coliform bacteria and E. coli in source water and contaminated drinking water.
Enumeration of Sulphite-Reducing Clostridia from Potable Water Supplies
Authors: Sartory D. P. , Pritchard A. M. , Holmes P.
Published: May 2018

The enumeration of sulphite-reducing Clostridia from water upon egg yolk-free tryptose-sulphite-cycloserine agar (TSC) was evaluated against the standard UK method of enumeration upon membrane-clostridial agar (MCA), with or without heat treatment of the sample. Using 280 samples of treated drinking water, raw groundwater, river water and sewage effluent, the recoveries of presumptive sulphite-reducing Clostridia were significantly higher on TSC than on MCA (both incubated at .37°C for 48 h), particularly from potable water samples where the system integrity had been breached. Clostridia were isolated from 26 of the 224 groundwater and drinking water samples, on 25 occasions with TSC but on only 3 occasions with MCA. From river water and sewage effluent samples, background growth was higher on TSC. Of 85 isolates from TSC, 92.9% were confirmed as Clostridia, whilst only 56.5% of 23 isolates from MCA confirmed, the remaining being Gram-positive rods and cocci and Gram-negative rods. Heat treatment of samples to 70°C for ten minutes prior to filtration did not affect counts on MCA, but significantly reduced both Clostridia and background counts on TSC. Clostridia isolated from compromised treated water supplies include Cloistridium perfringens, C. bgratii, C. difficile, C. limosum and C. subtgrminale.
Mechanisms of Viral Capture by Microfiltration
Authors: McGahey Christopher , Olivieri Vincent P.
Published: May 2018

The male-specific bacterial virus MS2 is being used in this study to investigate the mechanisms of virus capture from aqueous suspension by a polypropylene microfilter. Mechanisms being studied include 1) adsorption of viruses to clean, unused filters; 2) adsorption of viruses to used filters; 3) capture of particulates formed from virus complexation with organic or inorganic materials; and 4) entrapment of viruses by a barrier layer generated by these materials on the outer surface of the filter. Batch studies were conducted using chopped filter material to quantify virus adsorption to unused filters. Identical studies are planned to examine used filters. Constant pressure studies using manufactured filter modules will be performed to assess the importance of complexation and barrier layer formation. Ranges of values of solution pH and ionic strength are to be examined in combination with varied concentrations of inorganic suspended solids, organic suspended solids and dissolved organic material to determine method and extent of virus capture. Initial data show adsorption directiy to an unused filter surface to be negligible between pH3 and pH10. Data is being collected to quantify the relative contribution of each of the other three mechanisms.
The Inactivation of Hepatitis a Virus and other Model Viruses by UV Irradiation
Authors: Battigelli D. A. , Sobsey M. D. , Lobe D. C.
Published: May 2018

Ultraviolet light is an attractive alternative to chemical disinfection of water, but little is known about its ability to inactivate important waterborne pathogens such as hepatitis A virus. Therefore, the sensitivity of HAV strain HM-175, coxsackievirus type B-5, rotavirus strain SA-11, and bacteriophages MS2 and øX174 to ultraviolet radiation of 254 nm wavelength in phosphate buffered water was determined. Purified stocks of the viruses were combined and exposed to collimated UV radiation in a stirred reactor for a total dose of up to 40 mW sec/cm2. Virus survival kinetics were determined from samples removed at dose intervals. The 4 log,10 (99.99%) inactivation doses for HAV, CB5, SA-11 and øX174 were 16, 29, 42 and 9 mW sec/cm2, respectively. MS2 exhibited the greatest resistance in buffered water with less than a 1 log10 reduction observed after exposure to 25 mW sec/cm2. A 15 mW sec/cm2 exposure induced a 7 log10 reduction of øX174, while inactivation of HAV, CB5 and SAll was intermediate, with at least 3 log10 reductions occurring after a 20 mW sec/cm2 exposure. The results of these experiments indicate that UV radiation can effectively inactivate viruses of public health concern in drinking water.
Inactivation of Hepatitis a Virus and MS2 by Ozone and Ozone-Hydrogen Peroxide in Buffered Water
Authors: Hall Richard M. , Sobsey Mark D.
Published: May 2018

The comparative inactivation of highly purified hepatitis A virus (HAV) and MS2 by 1 mg H2O2/L, 2.0 and 0.4 mg O3/L, and 2.0 mg O3/L plus 0.6, 1.0, or 1.6 mg H2O2/L, at 3-10°C, in 0.01 M phosphate buffer (pH 6-10) was determined. Both HAV and MS2 were completely inactivated (3.9-6 log10) within 5 seconds in ozone solutions. Hydrogen peroxide did not inactivate MS2, but did inactivate 95% of the HAV. Both HAV and MS2 were completely (3.3-5.5 log) inactivated within 5 seconds in the oxidant mixtures at pH 6-8, but MS2 survival exceeded that of HAV at pH 10. MS2 was found to be a good model for predicting HAV inactivation by ozone and mixtures of ozone and hydrogen peroxide when both viruses are purified in the same manner.
Comparative Survival of E. Coli, F+Bacteriophages, HAV and Poliovirus 1 in Wastewater and Groundwater
Authors: Nasser A. M. , Tchorch Y. , Fattal B.
Published: May 2018

This study was designed to compare the die-off of E.coli and F*bacteriophages with that of enteric pathogenic viruses in groundwater and raw wastewater at various temperatures.

At low temperatures, the die-off of E.coli was greater than that of HAV and poliovirus 1. Under conditions compatible with bacterial growth no die-off of E.coli was observed. Under most experimental conditions no die-off was observed for F*bacteriophages. The survival of HAV and poliovirus 1 was strongly affected by temperature. Regardless of the water type, the highest die-off of viruses was observed at 30°C, whereas at 10°C the titer of HAV and poliovirus 1 was reduced by 1 to 2 log10 after 90 days incubation. The data presented in this study indicated that E.coli cannot serve as an index for the survival of HAV and poliovirus 1 in ground and wastewater. Since F+bacteriophages were not affected by the tested conditions, their acceptance as indicators for viral pollution of water sources needs further evaluation.
Virus Survival in Sewage Sludge Amended Desert Soil
Authors: Straub Timothy M. , Pepper Ian L. , Gerba Charles P.
Published: May 2018

Currently Pima County, Arizona, disposes all of its anaerobically digested sewage sludge in liquid form (1.5% solids) on agricultural land used for non-food crop production by subsurface injection or surface spreading. Present in these sludges are human enteric viruses in concentrations as high as 1,000 per liter of sludge. These viruses could potentially contaminate surface and groundwater sources during periods of irrigation or extended rainfall. This study was designed to assess the survival of viruses under field conditions typical of the arid Southwestern United States during the winter and summer months. This study was also conducted in the laboratory to simulate field conditions. Soil samples taken from freshly amended fields were seeded with poliovirus type 1 (stock titer = 106/ml) and bacteriophage MS-2 (stock titer = 1010/ml)and thoroughly mixed with the sludged soil. The seeded samples were put into containers and buried 10 cm below the soil surface, and samples were taken at pre-determined time intervals. Average soil temperature (measured at the 10 cm depth) ranged from 15°C in the winter to 33°C in the summer. Soil moisture decreased from 25% to 15% in the winter and from 40% to less than 5 % in the summer. During the winter study, no inactivation of poliovirus was observed after 7 days, while greater than a 90% reduction was observed for MS-2. During the summer study, no poliovirus was recovered after 7 days, and no MS-2 was recovered after 3 days. The results of this study suggest that high soil temperature and rapid loss of moisture limit the survival of viruses in desert soils.
A Performance-Based Regulatory Program for Phosphorus Control to Prevent the Accelerated Eutrophication of Lake Okeechobee, Florida
Authors: Goldstein Alan L. , Ritter Gary J.
Published: May 2018

Following 15 years of data collection, field studies, and modeling efforts, the State of Florida in 1987 legislatively mandated the South Florida Water Management District, a regional water management agency, to create and implement a plan to reduce average annual inputs of total phosphorus to Lake Okeechobee by 40 percent. One element of the resulting plan was the creation and implementation of a performance-based regulatory program that set phosphorus discharge limitations for all parcels of land equal to or greater than 1/2 acre in size in almost all of the 1,735,000 acres of the lake's 31 tributary drainage basins. Owners of non-complying parcels are required to take measures to bring the parcels into compliance.

This regulatory program, coupled with concurrent cost-share incentive programs and ongoing research efforts, has resulted in a decrease in phosphorus concentrations from individual properties and at some tributary discharge locations to the lake.

This effort demonstrates that where there is sufficient historical information, scientific application of state-of-the-art modeling techniques, a political will, and appropriate powers vested in the institutions to take and enforce actions, such programs can be implemented and have positive effects on reducing non-point source pollutants.
A Decision Support System for Evaluating the Effects of Alternative Farm Management Systems on Water Quality and Economics
Authors: Yakowitz D. S. , Stone J. J. , Lane L. J. , Heilman P. , Masterson J. , Abolt J. , Imam B.
Published: May 2018

A prototype Multi-Objective Decision Support System (MODSS) for water quality has been developed by the Agricultural Research Service at the Southwest Watershed Research Center in Tucson, Arizona. The Decision Support System uses a simulation model to predict the impact of alternative management systems on surface and groundwater quality as well as farm income. The results of the simulation, which includes modeling of hydrology, erosion, nutrient and pesticide transport, crop growth and economics, are analyzed with respect to the multiple objectives of reducing surface and groundwater pollution while maintaining or improving farm income. Often these objectives are in conflict and objectively discerning which practice is preferred can be a difficult task. The multi-objective decision making component of the decision support system makes use of dimensionless utility functions and the concept of importance order dominance. The MODSS allows the user to set up alternatives, choose the decision criteria, and accept or customize the decision mode settings. The results are presented graphically as well as in tabular form. The dominance of one practice over another, if it exists, is clearly evident in the graphical presentation. We illustrate the decision component of the MODSS with pictures of the screens from an example which uses the simulation results of several management alternatives on farmland in the Deep Loess Soil Major Land Resource Area near Treynor, Iowa.
Risk versus Economic Return in Managing Groundwater Nitrate Contamination
Authors: Adelman D. D. , Dahab M. F.
Published: May 2018

A nitrate transport model was developed to project the impact of a substantial buildup of nitrate in the groundwater in the eastern Sandhills region of Nebraska. Predicted nitrate levels were evaluated using a Multi-Criteria Decision Making technique. Two criteria were used to determine optimum farm management practices: economic return to the irrigators and risk to domestic water users. The optimum farm management practice consisted of an above average irrigation rate and a below average nitrogen fertilizer rate. The low fertilization rate had one of the lowest risks of excessive ground water nitrate levels, while the high irrigation rate maximized the economic return. Therefore, this practice was optimal because it was the best compromise between minimum risk and maximum economic return. The risk of excessive groundwater nitrate for the optimum practice was 51 percent and for the other seven practices simulated ranged up to 54 percent.