bluuebunny/crossref_metadata_2025_split huggingface dataset:
Specific Cake Resistance: Myth or Reality?
Authors: Tosun Ismail , Yetis Ulku , Willis Max S. , Chase George G. 
Published: May 2018

The specific cake resistance is considered to be the key factor in the characterization of sludge dewaterability. The use of this parameter without knowing how it is derived and the conditions under which it can be used has been creating a great deal of confusion in the literature. Moreover, the lack of a universally agreed test method to determine its value causes additional problems. Hence, attempts to go from the laboratory data to the full scale industrial equipment using this concept may end up in failure.
This paper starts with the origin of the specific cake resistance in the historical perspective of filtration theory. Currently used experimental techniques in the determination of specific cake resistance are reviewed, advantages and disadvantages axe succinctly summarized. An alternative way of characterization of sludges using a resistance function rather than a specific cake resistance is proposed.
Anaerobic-Aerobic Treatment of Potato-Starch Wastewater
Authors: Abeling U. , Seyfried C. F. 
Published: May 2018

Production of potato starch produces wastewaters with high concentrations of COD, nitrogen and phosphorus. The best known and most economical solution for the nearly full elimination of these substances is the two-stage anaerobic-aerobic treatment. The anaerobic pretreatment must only go so far as to maintain enough COD for biological nitrogen and phosphorus elimination in the aerobic stage. To optimize this process, several tests have been carried out on nitrification/denitrification by means of the intermediate product nitrite. The carbon consumption amounts to only 60% in comparison with denitrification via nitrate. The essential parameter for regulating the process is the concentration of free ammonia in the reactor. Concentrations of 1 to 5mg NH3/l inhibit the nitratation but not the nitritation. A separation of both partial steps is possible. The content of ammonia was controlled by means of continuous NH4 and pH measuring.
The process is suitable for many wastewaters with low COD/TKN ratios and high nitrogen concentrations. If there are undesired nitrite peaks in an aerobic treatment plant caused by high pH values and temperatures, specific nitrogen elimination by means of nitrite is a reliable treatment system.
Standardisation of Small Wastewater Treatment Plants for Rapid Design and Implementation
Authors: Crabtree H. E. , Rowell M. R. 
Published: May 2018

Severn Trent Water was faced with the problem of rapidly implementing a massive capital investment programme to replace a large number of its small sewage treatment works. To meet the investment targets it was necessary to streamline the process of planning, design, construction and overall procurement of plant and equipment.
Key elements in achieving these targets were seen as:Standardisation of treatment processes and plant to reduce design times and construction periods and to guarantee performance.Use of standard specifications and procurement practice to ensure rapid acquisition of plant to the required design standards.
The Company's experience of operating a large number of different types of sewage treatment plant was used to standardise treatment processes for small works on the rotating biological contactor (RBC) and the reed bed.
Dewatering of Drying Beds–Combined Biological-Chemical Sludge Behaviour
Authors: Marklund S. 
Published: May 2018

Aerobically digested sludge from a small wastewater treatment plant was dewatered on five sand drying pilot beds and four small drainage beds. The experiment was conducted in a controlled environment with constant air humidity and temperature. A total of between 147 and 263 kg of a combined biological-chemical sludge was used on each of the sand drying beds. Initial sludge total solids (TS) content was 4.6 - 5.5%.
Sludge drainage was completed within 28 days, and the thinner sludge layers were drained within 16 days. The sludge evaporation phase, prior to equilibrium with air moisture, lasted a maximum of 84 days and resulted in a final TS content of 88 - 92%. The drying time to achieve 30% TS was 35-50 days, depending on initial sludge thickness. Sludge cracking behaviour or rate did not control the drying rate at less than 30% TS.
Using Diurnal Variations in a High Rate Algal Pond for Management Pattern
Authors: Picot B. , Moersidik S. , Casellas C. , Bontoux J. 
Published: May 2018

The high rate algal pond (HRAP) is an efficient low cost wastewater system. It is well adapted to small communities with high summer loads.
Many studies have been carried out on HRAP in order to adapt them to the seasonal variations of climate but very few have been devoted to the diurnal behavior of the system which could be an important design parameter.
The work for this investigation was carried out at the ‘Centre de Lagunage de Recherche Pluridisciplinaire‘ in Mèze, France, community located on the Mediterranean
The results show that all variables, except COD, do have diurnal variations. During daylight, photosynthetic activity is at its peak between 13:00 GMT and 15:00 GMT with oxygen saturation rates of 350 %, high pH's (pH&gt;9) and low total alkalinity. The highest removal rates of NH4-N and PO4-P are 94 % and 89 % respectively. During the night, photosynthesis stops and the dissolved oxygen concentrations drop to very low levels or even to zero. pH decreases (8.6) and total alkalinity increases as a consequence of the intense respiration of the algae and other organisms of the system.The various efficiencies decrease. Nutrient removal is linked to the variations of solar radiation and temperature which are considered as the main characteristics controlling algal activity. Algae contribute to the elimination of nutrients through two mechanisms: biological uptake and pH increase causing a volatilization of NH3 and a chemical precipitation of calcium phosphates. The decrease of the performances of a HRAP during the night is caused on the one hand by the interruption of photosynthesis combined with respiration, causing a decrease in pH and, on the other hand, to the continued inflow of sewage in the pond. The knowledge of the diurnal behavior of HRAP leads to a new concept of pond management. When HRAP pond effluent was withheld according to photosynthetic activity, this resulted in a more efficient removal of nutrients. Automatic systems tied to time or pH could control the release of effluent and easily implement such a management.
Observations of Particle Detachment during Filter Backwashing
Authors: Fitzpatrick C. S. B. 
Published: May 2018

The behaviour of filter grains and detaching deposits during backwashing was investigated at University College London using a High Speed Video and endoscope technique.
A detailed understanding of the backwashing process was required after decades of backwashing on a trial and error basis. This investigation provided detailed visual information on detaching deposits and bed behaviour.
Experiments were performed using standard filter sand and synthetic suspensions. The endoscope viewed inside the sand bed and a high speed video camera recorded what happened, during the backwashing process, on a pore/grain scale with a video screen magnification of about 100X. The video material was analysed and grain velocities obtained.
Results showed that combined air and water wash at collapse-pulsing gives best cleaning, due to the high degree of bed agitation resulting in high fluid shear stresses and maximising grain collisions. It has been observed that fluid shear forces dominate detachment, whether the bed is cleaned by water fluidisation or collapse-pulsing. During collapse-pulsing grains exhibit velocities as high as those measured for a fully fluidised bed. Since this degree of agitation is obtained for flow rates of around 40% of the water fluidising rate this represents a saving in the use of clean water for backwashing purposes.
Batch Operated Activated Sludge Plant for Production of High Effluent Quality at Small Works
Authors: Chambers B. 
Published: May 2018

In the UK there are about 7500 sewage treatment works of which 85% serve populations of less than 5000. Many of the smaller works do not comply with effluent quality standards and options for improving treatment are being pursued by many water companies. WRc have developed designs for packaged activated sludge systems to serve populations in the range 100 - 1000 persons. A detailed design has been completed for a population equivalent of about 600. Target effluent quality is 15:20:5 mg/l of BOD, SS and ammonia nitrogen respectively on a 95 percentile basis. The activated sludge system is designed to operate as a batch process with aeration and sludge settlement both occurring in the same tank. Batch operated activated sludge plants are known to produce sludges with good settling properties providing the influent wastewater is admitted into the aeration tank in controlled manner. Therefore a specially designed holding tank has been included as the first stage in the treatment sequence.
All process tanks are specified as glass-coated steel installed on a flat concrete base. Target construction cost for 600 population is ₤350 per capita.
Influence of Algal Species and Cultivation Conditions on Algal Removal in Direct Filtration
Authors: Petruševski B. , Vlaški A. , van Breeman A. N. , Alaerts G. J. 
Published: May 2018

The influence of growth media on the behaviour of cultured algae in direct filtration was examined. Cultured Chlorella vulgaris and Selenastrum capricornutum on Jaworski and Z-8 media are used for model water preparation. It was found that the same algal species in the same growth phase had different responses under identical treatment conditions. Also, difference in growth phase influenced their behaviour. Therefore, assuming similarity between cultured algae and algae from natural waters is highly questionable.
The efficiency of the direct filtration treatment process for the removal of dominant algal species present in Biesbosch Water Storage Reservoirs was investigated. Different removal patterns were found for various algal species. The most difficult to be removed were Rhodomonas minuta and µ-algae. High removal efficiency was found for Stephanodiscus hantzschii and other cylindrical diatoms. An overall algal biomass removal of 90 % was achieved. Algal penetration through filters is a consequence of algal size and inefficient agglomeration during coagulation. It was found that the application of oxidants (ozone and potassium permanganate) prior to coagulant addition improves the efficiency of direct filtration. The use of H2O2 did not enhance algal removal under the conditions investigated.
Comparison and Evaluation of Different Microbiological Quality Criteria for Shellfish and Shellfish-Growing Waters
Authors: Martinez-Manzanares E. , Moriñigo M. A. , Castro D. , Balebona M. C. , Borrego J. J. 
Published: May 2018

The objective of this study is to compare different microbiological criteria based on the control of shellfish-growing waters and shellfish flesh, to assess the microbiological quality of the shellfish harvested in a marine zone affected by discharges of a moderately polluted river.
Two species of shellfish grown in Mediterranean countries, cockles (Cardium edule) and striped venus (Chamelea gallina) were chosen to carry out this study. A total of 55 samples of diellfish and sea water were collected over the four seasons of the year.
According to the results obtained, the US, EEC and Spanish criteria, based on the level of faecal coliforms in shellfish flesh, guaranteed appropriately their safety for human consumption, but among the criteria based on the level of Escherichia coli, only the Australian criterion has been shown to be totally safe, this microorganism being the best indicator of the presence of Vibrio parahaemolyticus and Salmonella.
For the criteria based on the analysis of indicators in seawater, the indicators which relate to the age of faecal pollution, such as spores of clostridium sulfite reducer and faecal streptococci are the best indexes of the presence of pathogens in shellfish. Furthermore, criteria that establish the percentage of water samples that fulfill the microbiological level specified, or log-normal distributions of indicators such as total coliforms, faecal coliforms and E. coli, are better than mean counts.
Effective Monitoring Strategies for Demonstrating Water Quality Changes from Nonpoint Source Controls on a Watershed Scale
Authors: Spooner Jean , Line Daniel E. 
Published: May 2018

Demonstrating water quality improvements from nonpoint source (NPS) controls by monitoring both land treatment and water quality in at least a subset of watershed projects is necessary to provide feedback to project coordinators Feedback to regional and national policy makers is also essential to achieve political and economic support for NPS control programs. To meet this objective, two challenges must be met in designing the monitoring network and analyzing the data: (1) Detecting significant (or real) trends in both water quality and land treatment implementation and (2) Associating water quality trends with land treatment trends.
Land treatment and water quality monitoring requirements for meeting these challenges are discussed based on lessons learned from the Rural Clean Water Program, a 10-15 year experimental program designed to control agricultural NPS pollution in rural watersheds. At minimum, monitoring of land treatment and water quality should be multi-year before and after best management practice (BMP) implementation. The paired watershed design is the best for documenting BMP effectiveness in the shortest number of years (a minimum of 3-5 years). The water quality and land treatment data bases should be temporally related. All significant sources of variability in the land treatment and water quality data should be taken into account to increase the chances of isolating true water quality changes due to BMPs.
Chemical and Physical Properties of Emissions from Kuwaiti Oil Fires
Authors: Stevens R. , Pinto J. , Mamane Y. , Ondov J. , Abdulraheem M. , Al-Majed N. , Sadek M. , Cofer W. , Ellenson W. , Kellogg R. 
Published: May 2018

After the Iraqi retreat from Kuwait in 1991, airborne sampling was conducted in the oil fire plumes near Kuwait City and ground-level samples were taken of the air within the city. For the airborne sampling, a versatile air pollution sampler was used to determine the SO2, elemental concentrations, the aerosol mass loadings and SO42− and NO3 concentrations. Striking differences between the black and white plumes were associated with high concentrations of NaCl and CaCI2 measured in the white plumes and large numbers of carbon chain agglomerates in the black plumes. For the ground-based measurements, an annular denuder system was used to determine levels of SO2, SO42−, trace elements, and mass loadings. Certain pollutant levels rose in the city during inversion conditions, when winds were too weak to continue moving the combustion products directly to the Persian Gulf, and the increased levels of Pb and certain trace elements were comparable to those in other large urban areas in Europe.
This paper has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
Microbiological Purification of Fish Grown in Fecally Contaminated Commercial Fish Pond
Authors: Fattal B. , Dotan A. , Parpari L. , Tchorsh Y. , Cabelli V. J. 
Published: May 2018

The digestive tracts of tilapia reared in commercial fish ponds with animal manure and/or municipal wastewater generally were contaminated with the fecal indicators E.coli and enterococci to levels greater than those in the environmental water. When the indicator densitites in the water were sufficiently high, the liver and muscle tissue also became contaminated, albeit to much lower levels. Thermotolerant aeromonas were recovered from the environmental water and fish tissues at levels 2-4 logs higher than those of the fecal indicators. Accumulation of the indicators in the tissues of the naturally contaminated (pond) fish generally was greater than that in the artificially contaminated fish.
The indicator levels in the tissues did not appreciably decrease when the pond-reared fish were maintained for 5-8 days under starvation conditions in tanks containing water which was not exchanged. However, the E.coli and virus levels in the tissues of experimentally contaminated tilapia were appreciably and significantly reduced under the same conditions. The results point out the limited value of conventional “purification” methods as applied to tilapia reared in fecally fertilized waters and of data obtained from studies with experimental animals. Since fish are cooked prior to consumption, the major public health concern could be the risk of Aeromonas wound infections among individuals who handle and process fish.
Soil Microarthropods on Post-Fire Pine Forest on Mount Carmel, Israel
Authors: Broza M. , Poliakov D. , Weber S. , Izhaki I. 
Published: May 2018

Soil microarthropods of pine forests in Israel were investigated for the first time. Eighty percent of them belonged to the orders Acari and Collembola, the remainder to another 18 orders. In the second post-fire year only 11 orders were presented. The groups Protura, Palpigradi and Pauropoda in Israel are described here for the first time. Protura and Pauropoda were quite common in the natural forest, but disappeared almost entirely after the fire. By contrast, the pseudococcid Rhizoecus sp., and to some extent also Palpigradi, were rare in unburned forest but behaved as pioneers and flourished two years post fire.
The Collembolan fauna were studied in more detail and four genera new to Israel have been identified already. The family Poduridae was the most common Collembolan in natural forest, but they almost disappeared after the fire, while the entomobryoid springtails did not change too much. It was concluded that soil microarthropods play an important role in post-fire succession and are good indicators of resilience processes.
Uprating and Development of a Regional Telemetry Scheme
Authors: Huntington R. 
Published: May 2018

In 1988 Wessex Water decided that its 10 year old regional telemetry system was in need of major uprating and improvement to meet their changing requirements. This paper explains the philosophy adopted in making the changes and describes the actual improvements carried out. While still based on a centralised system, two important changes included the use of more sophisticated outstations and the provision of a networking facility to VDU's for use by geographically spaced operational staff.
A number of inter-linked software packages developed for the analysis, optimisation and modelling of data are described. Finally conclusions are drawn.
REMOVAL OF VOCs FROM REFINERY AND PETROCHEMICAL WASTEWATERS USING DISSOLVED AIR FLOTATION
Authors: Al-Muzaini S. , Khordagui H. , Hamouda M. F. 
Published: May 2018

A field sampling and analysis program was carried out at a refmery and petrochemical industrial complex in the Shuaiba Industrial Area to characterize the volatile organic compounds (VOCs) emitted from wastewater and examine their removal by dissolved air flotation (DAF) and granular activated carbon (GAC) treatment
Compounds such as benzene, toluene, ethylbenzene, and xylene were identified. The total VOC emission of these compounds ranged from 0.1 to 3.2 mglm3. The VOCs concentrations in wastewater ranged from 34 to 4445 g/l.
An actual refinery wastewater was fed at a rate of 10 l/min into a pilot scale 592-liter dissolved air flotation(OAF) unit connected to a granular activated carbon column. Results indicated that liquid detention time and air/water ratio were the main factors affecting VOCs stripping from the OAF basin. Up to 20% of influent VOCs concentrations were lost by volatilization at an air-to-water ratio of 0.5. Adsorption by dry granular activated carbon (GAC) was capable of reducing the VOCs concentration in off-gas from the OAF unit by more than 99%. It is recommended to couple covered OAF units with dry GAC columns to minimize occupational exposure to VOC emission.
A PROPOSED PATHWAY FOR THE BIODEGRADATION OF HEXAMETHYLENETETRAMINE
Authors: Colquhoun K. O. 
Published: May 2018

A study has been performed on two Pink Pigmented Facultative Methylotrophic (PPFM) bacteria isolated from activated sludge previously exposed to Hexamethylenetetramine (Hexa), Colquhoun and Smith (1988) and Colquhoun (1988). There are four possible pathways found in methylotrophs which can be used to break down formaldehyde, one of the two constituents of Hexa (Zatman 1980). These pathways are: (i) Ribulose monophosphate pathway (RuMP); (ii) Xylulose monophosphate pathway (XuMP); (iii) Ribulosebiphosphate carboxylase pathway (RuBPC) and (iv) Serine pathway.
However, before any of these pathways can make use of the formaldehyde present in Hexa it must first be made available by breaking up the Hexa molecule. Two possible mechanisms by which Hexa might be broken down are proposed. The first reported by Tada (1960) and Strom and Won Jun (1980) whereby Hexa is broken down to formaldehyde and ammonia under acid conditions. This mode of action has been exploited when Hexa has been used in the long term therapy of chronic urinary tract infections with the antimicrobial activity resulting from the production of formaldehyde.
The other possible mechanism is a combined physicochemical and biological function proposed by Bodik et al. (1991). In this mechanism there is no direct biological action on the Hexa molecule, it is dependent upon the nitrification of ammonia which produces H+ ions which can hydrolyse Hexa to ammonia and formaldehyde. The formaldehyde is either metabolised or it exhibits an inhibitory effect on the microbial population whilst the ammonia is nitrified which in turn produces more H+ ions which hydrolyses more Hexa and perpetuates the cycle.
This study will demonstrate which of these degradative pathways is the most probable for the isolated PPFM's.
PILOT -SCALE, HIGH-STRENGTH INDUSTRIAL WASTEWATER TREATMENT EVALUATION BY MATHEMATICAL MODELLING
Authors: Dobolyi Elemér , Takács Imre 
Published: May 2018

An existing rendering plant wastewater treatment facility has to be upgraded to meet the newly set British and more stringent EC effluent standards. After detailed analysis it turned out, that the existing treatment plant cannot be upgraded, a new plant has to be built. The rendering plant processes slaughterhouse wastes. The wastewater contains easily biodegradable organic substances, mainly organic acids, organic bonded nitrogen and ammonia. According to the new effluent standards the main task, besides the organic removal was the complete removal of nitrogen. The aim of this study was to find out the best available technology and the basic wastewater design data. For this purpose, on site pilot scale experiments were carried out. In several test runs the influent BOD and T K N have varied of between 1400-5500 and 460-1120 mg/l, respectively. Based on the experimental results, single-sludge nitrification-denitrification technology was selected for the full scale treatment plant. The plant was extended by chemical phosphate removal applying the post-precipitation method.
In addition to the experimental schedule, a mathematical model of the plant was developed for two purposes.– to verify the applicability of the general activated sludge model under high concentration influent conditions, and– to generalize experimental results and provide a tool to predict plant performance under full scale conditions.
On the basis of successful pilot plant experiments and model calibration, full scale plant design parameters were determined and presented. The full scale plant is under construction.