bluuebunny/crossref_metadata_2025_split huggingface dataset:
Practical Guide to Determine the Impact of Radon and Other Radionuclides on Water Treatment Processes
Authors: Martins K. L. 
Published: May 2018

During treatment of groundwater, radon is often coincidentally removed by processes typically used to remove volatile organic compounds (VOCs)-for example, processes such as liquid-phase granular activated carbon (LGAC) adsorption and air stripping with vapor-phase carbon (VGAC). The removal of radon from drinking water is a positive benefit for the water user; however, the accumulation of radon on activated carbon may cause radiologic hazards for the water treatment plant operators and the spent carbon may be considered a low-level radioactive waste.
To date, most literature on radon removal by water treatment processes was based on bench- or residential-scale systems. This paper addresses the impact of radon on municipal and industrial-scale applications. Available data have been used todevelop graphical methods of estimating the radioactivity exposure rates to facility operators and determine the fate of spent carbon.
This paper will allow the reader to determine the potential for impact of radon on the system design and operation as follows.Estimate the percent removal of radon from water by LGAC adsorbers and packed tower air strippers. Also, a method to estimate the percent removal of radon by VGAC used for air stripper off-gas will be provided.Estimate if your local radon levels are such that the safety guidelines, suggested by USEPA (United States Environmental Protection Agency), of 25 mR/yr (0.1 mR/day) for radioactivity exposure may or may not be exceeded.Estimate the disposal requirements of the waste carbon for LGAC systems and VGAC for air stripper “Off-Gas” systems.
Options for dealing with high radon levels are presented.
Dynamic Models for Clarifiers of Activated Sludge Plants with Dry and Wet Weather Flows
Authors: Otterpohl R. , Freund M. 
Published: May 2018

Dynamic simulation of wastewater treatment plants becomes more realistic, if models of primary and secondary clarification are implemented. A simple model of the primary clarifier can describe dynamics of buffered influent or sludge water concentrations. Different changes in ratios of particulate fractions of COD depending on influent flows are modelled as well.
Processes in activated sludge plants are affected by the replacement of sludge to the clarifier and by the loss of solids through the effluent. These effects are very strong at combined water flows. The two models best applicable as of yet did not meet measured values for effluent solids. One of them describes thickening and storage of sludge quite well. The developed two component model presented here is able to represent the behaviour of secondary clarifiers at dry and wet weather flows.
Model of Algal Bacterial Clay Wastewater Treatment System
Authors: Carberry J. B. , Greene R. W. 
Published: May 2018

A computer model is presented for an innovative wastewater treatment process known as the Algae-Bacterial-Clay Treatment (ABCT) system. In this process the photosynthetic production of dissolved oxygen by algae supports the bacterial breakdown of organic matter in wastewater. Clay is added to the plug flow reactor to dampen input BOD variation. The model was developed to gain an improved understanding of transient behavior of dissolved oxygen and pH in the treatment reactor during typical operation.
The model consists of five nonlinear ordinary differential equations describing the time rate of change of algae mass, bacterial mass, organic substrate, dissolved oxygen, and dissolved carbon dioxide. A fourth-order Runge-Kutta integration technique was used to predict system response at discrete time steps. The pH variation expected from changes in dissolved carbon dioxide was based upon presumptions that the system is buffered by the carbonic acid system, and that alkalinity does not change appreciably during the course of time. These assumptions were confirmed by experimental results.
The model successfully predicted diurnal fluctuations in dissolved oxygen, carbon dioxide, and pH in the ABCT process. The model predicted that algae will supply sufficient oxygen during sunny and partly sunny days to eliminate the need for continuous mechanical aeration. This feature should result in significant cost savings over conventional secondary wastewater treatment schemes. Surplus dissolved oxygen produced by algae during the day should be completely depleted at night due to bacterial respiration. This lack of oxygen, in turn, resulted in reduced substrate utilization and potential effluent discharge violations. Mechanical aeration during the night might be one possible remedial strategy. Despite its dynamic behavior, the ABCT process would be a viable and potentially cost efficient wastewater treatment strategy.
Decrease in Toxicity of Pentachlorophenol and Toluene to Growth of Selected Microbial Consortia and Activated Sludge by Pretreatment with Phanerochaete chrysosporium
Authors: Bower Carberry J. , Kovach L. E. 
Published: May 2018

The white rot fungus Phanerochaete chrysosporium can degrade toxic compounds under specific nutrient conditions. This attribute was utilized in order to determine the effect of fungal pretreatment on model compounds pentachlorophenol and toluene. The fungal culture was purchased from ATCC, cultured on dextrose agar, and the mycelia harvested to degrade the model compounds. P. chrysosporium was able to degrade up to 74% of initial pentachlorophenol concentration in eight days and up to 31% initial toluene in 31 hours.
Specific growth rates of activated sludge and selected microbial consortia were determined on untreated and fungal-pretreated parent model compounds. Specific growth rates for activated sludge and selected microbial consortia were enhanced by fungal pretreatment of both model compounds. Specific growth rates indicated more efficient use of toluene by activated sludge than by toluene-selected microbial consortia, while pentachlorophenol- selected microbial consortia exhibited more favorable growth rates on pentachlorophenol than did activated sludge. Pretreatment results indicated that the toxicity of model compounds was reduced by fungal pretreatment. The growth rates were compared and used as an indication of toxicity reduction which can be exploited at contaminated waste sites or at industrial pretreatment facilities.
Rapid Removal of Colloidal Organics from Domestic Wastewater
Authors: Bunch B. W. , Griffin D. M. 
Published: May 2018

Batch experiments were conducted with raw wastewater and preaerated microbial sludge to investigate the removal behavior of the contact stabilization activated sludge process. This process was originally developed based on observed rapid drops in BOD which were attributed to rapid adsorption of colloidal organics. To date no data have been presented verifying that rapid colloidal adsorption occurs or is responsible for rapid BOD decreases.
Food to Microorganism (F:M) ratios were varied from 0.047 to 0.447 mg COD/mg MLSS during batch tests conducted with thirty minute contact times. Mixed liquor samples were collected at predetermined times, poisoned with mercuric chloride to halt microbial activity, and settled. Samples of the supernatant were drawn off and the COD of organics in different size ranges determined using a sequential filtering technique. Colloidal COD was defined to be the difference between the COD of organics passing a 1.5 µm filter and those passing a 0.03 µm filter.
Results indicated that rapid colloidal removal occurred. Colloidal COD concentrations decreased from initial values (maximum 85 mg/l) to near 0 mg/l within five minutes after mixing. Such behavior was only observed for the colloidal fraction and occurred regardless of the initial colloidal COD, total COD, or F:M ratio. It was concluded that physical coagulation was most likely the mechanism responsible for rapid colloidal removal.
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.
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.
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.
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
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.
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.
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.
Preliminary Evaluation of Effects of Best Management Practices in the Black Earth Creek, Wisconsin, Priority Watershed
Authors: Walker John F. , Graczyk David J. 
Published: May 2018

Nonpoint-source contamination accounts for a substantial part of the water quality problems in many watersheds. The Wisconsin Nonpoint Source Water Pollution Abatement Program provides matching money for voluntary implementation of various best management practices (BMPs). The effectiveness of BMPs on a drainage-basin scale has not been adequately assessed in Wisconsin by use of data collected before and after BMP implementation.
The U.S. Geological Survey, in cooperation with the Wisconsin Department of Natural Resources, monitored water quality in the Black Earth Creek watershed in southern Wisconsin from October 1984 through September 1986 (pre-BMP conditions). BMP implementation began during the summer of 1989 and is planned to continue through 1993. Data collection resumed in fall 1989 and is intended to provide information during the transitional period of BMP implementation (1990-93) and 2 years of post-BMP conditions (1994-95).
Preliminary results presented for two subbasins in the Black Earth Creek watershed (Brewery and Garfoot Creeks) are based on data collected during pre-BMP conditions and the first 3 years of the transitional period. The analysis includes the use of regressions to control for natural variability in the data and, hence, enhance the ability to detect changes. Data collected to date (1992) indicate statistically significant differences in storm mass transport of suspended sediment and ammonia nitrogen at Brewery Creek. The central tendency of the regression residuals has decreased with the implementation of BMPs; hence, the improvement in water quality in the Brewery Creek watershed is likely a result of BMP implementation. Differences in storm mass transport at Garfoot Creek were not detected, primarily because of an insufficient number of storms in the transitional period. As practice implementation continues, the additional data will be used to determine the level of management which results in significant improvements in water quality in the two watersheds. Future research will address techniques for including snowmelt runoff and early spring storms.
Low Cost Packaged Sewage Treatment Plant for Production of High Quality Effluent at Small Works
Authors: Chambers B. , Whitaker J. , Elvidge A. F. 
Published: May 2018

In the UK there are over 7000 small works which treat the sewage from populations of less than 10,000. Many of these works are at risk of non-compliance with effluent quality consents and options for improving the standard of treatment are being pursued by many utilities.
WRc and Anglian Water Services have developed designs for packaged sewage treatment plants to serve populations in the range of 1000-10,000. A demonstration plant has been constructed at the Waterbeach STW of Anglian Water to serve a population of about 6,500. Target effluent quality is 15:20:5mg/l of BOD, SS and ammonia nitrogen respectively on a 95 percentile basis.
Following plant commissioning a process performance evaluation programme was commenced in February 1991. Nitrification was established after about 6 weeks of operation but suspended solids values have been affected by the presence of a stable foam on the surface of the aeration tank. Process modifications have reduced the effect of this phenomenon substantially and effluent quality has improved.