bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Chlorination on Organocyanide Compounds
Authors: Yi Ying , Theis Thomas L. , Young Thomas C.
Published: September 2006

Results are presented that explore the possibility of organocyanide compounds in wastewater contributing to elevated cyanide levels in the chlorinated effluents of publicly owned treatment works. Four model compounds, acetonitrile, amygdalin, cyanocobalamin, and 2‐acetoxy‐3‐butenenitrile, were selected and tested with varying chlorine dosages for release of cyanide by total and diffusible cyanide procedures. The coenzyme form of vitamin B12, which does not contain cyanide, was also tested. It was found that acetonitrile and amygdalin do not yield cyanide with or without chlorination, cyanocobalamin had increased release with increased chlorine dosages, and 2‐acetoxy‐3‐butenenitrile had generally decreased release of cyanide with increased chlorine dosages. Both cyanocobalamin and coenzyme vitamin B12 gave evidence of the formation of the cobalt–cyanide complex after chlorination, even though the molecular structure of the coenzyme vitamin B12 contains no cyanide.
A New Process for Enriching Nitrifiers in Activated Sludge Through Separate Heterotrophic Wasting from Biofilm Carriers
Authors: Parker Denny S. , Rusten Bjørn , Wien Asgeir , Siljudalen Jon G.
Published: September 2006

A new process, the biofilm–activated sludge innovative nitrification (BASIN) process, consisting of a moving‐bed biofilm reactor (MBBR) with separate heterotrophic wasting, followed by an activated‐sludge process, has been proposed to reduce the volumetric requirements of the activated‐sludge process for nitrification. The basic principle is to remove chemical oxygen demand on the biofilm carriers by heterotrophic organisms and then to waste a portion of the heterotrophic biomass before it can be released into the activated‐sludge reactor. By this means, the amount of heterotrophic organisms grown in the activated‐sludge reactor is reduced, thereby reducing the volume of that tank needed for nitrification. For nitrification applications, the simplest method for stripping biomass was to use an in‐tank technique using high shearing rates with aeration. Bench‐scale testing showed sludge yields in the BASIN process were one‐half of that in a control activated‐sludge process and twice that of a process line with intermediate settling between the MBBR and activated‐sludge stage. Critical washout solids retention times for nitrifiers were the same for all three lines, so activated‐sludge volumes for the BASIN process could be reduced by 50% compared with the control. Originally conceived process concepts for the BASIN process were confirmed by the experimental work.
Effect of Some Environmental Factors on Mercury(II) Reduction by Suspended Particulate Matter‐Associated Kluvera cryocrescens Biofilms in Waterbodies
Authors: Wang Wenhua , Huang Yabing , Liu Junhua , Peng An
Published: September 2006

To resist the invasion of harmful external substances, microorganisms tend to attach to submerged surfaces in aquatic systems. The current study focused on the influence of environmental factors (e. g., pH value of the culture, oxidation–reduction condition, light, and cultured age of bacteria on the reduction of mercury(II) to elemental mercury (Hg0) that occurred on the surfaces of suspended particulate matter. A simulated biofilm system consisting of bacterium Kluvera cryocrescens separated from suspended particulate matter in the Yangtze River (China), its exopolysaccharide, and kaolinite (BEK) was used to study the transformation of mercury(II) in an aquatic system. The results showed that the reduction of mercury from mercury(II) to elemental mercury was favored in a neutral pH, light, and aerobic surrounding while a low pH, dark, and anaerobic condition inhibited the reaction. Moreover, the reduction capacity of both biofilms and free bacteria decreased with the increase of cultured age. Under all experimental conditions, the reduction capacity of biofilms was lower than that of the free bacteria, suggesting that biofilm, as a microecosystem, might function as a buffer to protect the effect of mercury(II) and the surrounding change on microorganisms.
Reduction of Enteric Microbes in Flushed Swine Wastewater Treated by a Biological Aerated Filter and UV Irradiation
Authors: Hill Vincent R. , Kantardjieff Alexandra , Sobsey Mark D. , Westerman Phil W.
Published: September 2006

An aerobic biofilter system was studied to assess its effectiveness for reducing enteric microbial indicators in flushed swine wastewater under different seasonal conditions. A laboratory‐scale, low‐pressure UV collimated beam apparatus was used to investigate the effectiveness of UV irradiation for inactivating enteric bacteria, coliphages, and bacterial spores in treated and untreated swine wastewater having unfiltered absorbances of 5 to 11 cm−1 and total suspended solids concentrations of 500 to 1200 mg/L. Fecal coliforms, Escherichia coli, enterococci, somatic coliphages, and male‐specific coliphages were reduced by 97 to 99% in the biofilter system when reactor water temperatures were between 23 and 32 °C. Salmonella were reduced by 95 to 97% when water temperatures were 17 to 32 °C. Of the six microbial indicators studied, Clostridium perfringens spores were typically reduced the least by the biofilter system. At an average absorbed UV irradiation dose of 13 mJ/cm 2 , maximum reductions of fecal coliforms, E. coli, enterococci, C. perfringens spores, and somatic coliphages in biofilter system effluent were 2.2, 2.1, 1.3, 0.2, and 2.3 log10, respectively. The results of this study show that the aerobic biofilter system can be an effective alternative for treatment of flushed swine waste. Ultraviolet irradiation can be effective for further reducing enteric microbe concentrations in biologically‐treated swine waste, as well as in lower quality wastewaters, indicating its general potential for pathogen reductions in low‐quality wastewaters intended for beneficial reuse.
Pollutant Export from Various Land Uses in the Upper Neuse River Basin
Authors: Line Daniel E. , White Nancy M. , Osmond Deanna L. , Jennings Gregory D. , Mojonnier Carolyn B.
Published: September 2006

Because of the relatively high variability of pollutant export from urban land uses, a significant number of monitoring studies, including data from many storms, are needed to adequately characterize export from urban land uses. Pollutant runoff from six small drainage areas with different land uses was monitored for at least 20 storm events over the course of more than 1 year. The land uses included single‐family residential, golf course, industrial, dairy cow pasture, construction site, and wooded site. Average event mean concentrations and total annual load were computed for nitrogen forms, total phosphorus, and sediment from the land uses. Annual total nitrogen export was greatest for the construction land use during the house‐building phase, followed closely by the residential and golf course land uses. Total phosphorus export was greatest for the golf course site followed by the pasture and residential land uses. Sediment export was greatest for the construction site during the rough grading phase, which averaged more than 10 times more sediment export than any of the other sites. To estimate export from a multiuse urban watershed, total nitrogen, phosphorus, and sediment export from the residential, golf course, and construction sites were averaged. The average total nitrogen, phosphorus, and sediment export from the three land uses was, respectively, 269, 302, and 256% greater than the corresponding exports from the wooded site, which was considered similar to the predevelopment land use. Additionally, analyses of rainfall samples indicated that a considerable portion of the nitrogen export from these sites likely comes from nitrogen in rainfall.
Catalytically Assisted Electrochemical Oxidation of Dye Acid Red B
Authors: Shen Z. , Wang W. , Jia J. , Feng X. , Hu W. , Peng A.
Published: September 2006

This study focused on the degradation of dye Acid Red B in a catalytic electrolysis system with a semiconductor suspended in the electric field. The study showed that the addition of titanium dioxide substantially enhances the degradation of dye and that a semiconductor catalyst can improve electrolysis efficiency. This catalytic system has great potential to be applied commercially with the development of the catalyst. Analytical measurements show that some acidic compounds are produced in the treatment process and that biodegradability of the solution increases after electrolysis because of the breakdown of molecules. The UV–visible spectrum also indicates that the conjugated bonds of dye Acid Red B must be destroyed and that the molecules are broken into small ones. Furthermore, the results from the IR spectrum indicate that the nitrogen–nitrogen double bond of dye Acid Red B must be oxidized to nitrate. Electrochemical measurements show an apparent dye oxidation peak from 0.65 to 0.85 V (versus the saturated calomel electrode) in dye solution (10 g/L), confirming that dye is oxidized in this catalytic system.
Effect of Varying Solids Concentration and Organic Loading on the Performance of Temperature Phased Anaerobic Digestion Process
Authors: Vandenburgh Scott R. , Ellis Timothy G.
Published: September 2006

The effect of varying total solids (TS) and volatile solids (VS) concentrations and organic loading on the performance of a temperature phased anaerobic digestion (TPAD) system treating a mixture of primary and waste activated sludges was evaluated. An optimum volatile solids destruction of 61.5% occurred at a feed concentration of 4.9% (corresponding to 3.8% VS concentration) in the system operated at a total detention time of 20 days. At a total solids concentration of 7.9% (5.8% VS concentration), the volatile solids destruction efficiency dropped to 52.5%. At all conditions (4.4 to 7.9% TS) the TPAD system was able to meet the requirements for Class A biosolids, including those for fecal coliform and volatile solids destruction. The effluent fecal coliform concentration never exceeded 628 most probable number (MPN)/g TS. Thermophilic biomass activity tests were run on both the thermophilic (55 °C) and the mesophilic (35 °C) sludge. Biomass from the thermophilic reactor showed much greater activity at 55 °C than at 35 °C. However, significant activity was still present when the test was run at 35 °C. Activity tests completed on samples from the mesophilic reactor also had high activities at 55 °C, sometimes equal to the activity of the thermophilic biomass. These results suggest that the bacterial consortia in the TPAD system may be temperature‐tolerant and not necessarily two distinct communities with two distinct temperature regimes as had been previously assumed.
Anaerobic Digestion of Aircraft Deicing Fluid Wastes: Interactions and Toxicity of Corrosion Inhibitors and Surfactants
Authors: Gruden Cyndee L. , Hernandez Mark
Published: September 2006

Corrosion inhibitors and surfactants are present in aircraft deicing fluids (ADFs) at significant concentrations (> 1% w/w). The purpose of this research was to study the interactions of a common nonionic surfactant with the commercially significant corrosion inhibitors used in modern ADF (4‐ and 5‐methylbenzotriazole [MeBT]), and to determine the effects of their mixture on the conventional anaerobic digestion process. In mesophilic anaerobic microcosms codigesting wastewater solids, propylene glycol, and MeBT, increasing surfactant levels resulted in enhanced MeBT sorption on digester solids. As judged by anaerobic toxicity assays, responses from digesters containing surfactant concentrations below their critical micelle concentration (CMC) suggested that low nonionic surfactant concentrations could facilitate a reduction in the apparent toxicity of MeBT. In microcosms exposed to surfactant concentrations above their CMC, no increase in MeBT solubility was observed, and the anaerobic toxicity response corresponded to control systems not containing surfactant. Direct microscopic measurements of digesting biomass using fluorescent phylogenetic probes (fluorescent in situ hybridization) revealed that members of the domain Bacteria were more sensitive to MeBT in the presence of surfactant than were members of the domain Archaea.
Disinfection of Wastewater Using a 20‐kHz Ultrasound Unit
Authors: Madge Bethany A. , Jensen James N.
Published: September 2006

The present study explored the application of a 20‐kHz ultrasound unit for the disinfection of domestic wastewater. Experiments were conducted in batch with an ultrasound probe. The disinfection efficiency of fecal coliform increased with ultrasound power input from 0.003 log kill/min at 70 W/L to 1.8 log kill/min at 1250 W/L. Disinfection data are well‐described by the Chick–Watson disinfection model (coefficient of dilution, n = 2.0) using ultrasound power in place of chemical concentration. Water quality did not affect disinfection efficiency significantly. Temperature increases experienced with ultrasonic treatment were significant. Attempts to control the temperature resulted in a marked decrease in disinfection efficiency. Experiments devised to quantify the role of thermal mechanisms revealed that of the total kill produced by ultrasound approximately 52% was attributed to heat, 36% to mechanical stresses associated with ultrasonically induced cavitation, and 12% to uncharacterized synergistic effects. Successful scale‐up was demonstrated using a 9.3‐L pilot‐scale ultrasound unit, operated under flow‐through conditions.
Low‐Strength Wastewater Treatment Using an Anaerobic Baffled Reactor
Authors: Manariotis Ioannis D. , Grigoropoulos Sotirios G.
Published: September 2006

A 14.7‐L, three‐chamber anaerobic baffled reactor (ABR) was used to evaluate the treatment of low‐strength synthetic wastewater (chemical oxygen demand [COD] of 300 to 400 mg/L) and assess process reactivation after a prolonged period of inactivity. The reactor was inoculated with anaerobic seed and start‐up was immediate. At 26 °C and hydraulic retention times (HRTs) of 24 and 12 hours, COD removal averaged 87.2 and 91.0%, respectively, and biogas yield for methane (CH4) was 0.184 and 0.102 m 3 CH4/kg COD removed, respectively. The ABR was reactivated after two years without feeding. Response was prompt and removal averaged 85.3% even during the initial 10‐day period. Lowering temperature to 16 °C did not impair removal efficiency at HRTs of 24 and 12 hours. However, biogas release decreased by 30% and apparent COD conversion to methane dropped by 24 and 31%, respectively. At the end of the study, biomass was mostly in the bottom of the reactor and had moved from the first to the second chamber, while organic stabilization was occurring essentially in the first two chambers (56.1 and 22.4%, respectively, in terms of COD).
Entrapped Mixed Microbial Cell Process for Combined Secondary and Tertiary Wastewater Treatment
Authors: Yang P.Y. , Cao K. , Kim S.J.
Published: September 2006

An entrapped mixed microbial cell (EMMC) process was investigated for simultaneous removal of carbon and nitrogen from a synthetic wastewater in a single bioreactor. The influent had a soluble chemical oxygen demand (SCOD)/nitrogen ratio varying from 4 to 15 and an alkalinity of 140 and 230 mg/L as calcium carbonate. An alternating schedule of intermittent aeration was used for two sizes of carriers: 10 × 10 × 10 mm3 and 20 × 20 × 20 mm3. The medium carrier (10 × 10 × 10 mm3) was found to achieve higher removals of nitrogen, chemical oxygen demand, and 5‐day biochemical oxygen demand of 92, 95, and 97%, respectively. These higher removal rates occurred at a 12‐hour hydraulic retention time (HRT), an aeration/nonaeration ratio of 0.5:2 hours, and an SCOD/nitrogen ratio of 15 in the influent. Influent alkalinity concentrations of 140 and 230 mg/L as calcium carbonate were found to have minimum effect on the removal of carbon and nitrogen. However, the oxidation‐reduction potential, ranging from – 100 to 400 mV (during air‐off period), provides better nitrogen removal efficiency to maintain the total nitrogen (nitrate, nitrite, and ammonium) less than 10 mg/L when an SCOD/nitrogen ratio of 10 or 15 is maintained in the influent. Nitrogen removal efficiency increased with increasing ratios of SCOD/nitrogen in the influent (i.e., SCOD/nitrogen ratio of 15 > 10 > 7 > 4.0). The results of actual wastewater operation based on a study of synthetic wastewater show that organics removal efficiencies (94.6 and 94.2%) and nitrogen removal efficiencies (61.0 and 60.9%) are similar for reactors packed with medium and large carriers, respectively, when they are operated with a 9‐hour HRT, an air on/air off ratio of 1 hour:2 hours and an SCOD/nitrogen ratio of 4.6.
Role of Hydrogen Peroxide and Hydroxyl Radical in Producing the Residual Effect of Ultraviolet Radiation
Authors: Alam M. Z. B. , Ohgaki S.
Published: September 2006

Residual effect of UV radiation on Microcystis aeruginosa and Escherichia coli K12 A/λ (F+) was studied under various conditions to examine if the formation of hydrogen peroxide (H2O2) and hydroxyl radical (OH−) can explain the residual biocidal action of UV radiation. Survival of test organisms, that is , M. aeruginosa and E. coli K12 A/λ (F+), in UV‐irradiated synthetic water was monitored to assess the residual effect after the UV radiation. Synthetic water with various compositions was used to understand the role of transition metals and photosensitizing organic molecules in producing the residual biocidal action. Ultraviolet‐irradiated synthetic water containing a photosensitizing element and ferric ion (Fe3+) showed residual biocidal effect for more than 7 days. No residual effect was observed in the absence of any photosensitizing element. A close relationship was observed between the residual effect and the formation of hydrogen peroxide in the UV‐irradiated water. Scavenging of hydrogen peroxide and hydroxyl radical from the UV‐irradiated water significantly reduced the residual biocidal action. Ultraviolet‐irradiation of synthetic water containing ferric ion was found to promote the formation of ferrous ion (Fe2+). Because ferrous ion can produce reactive species in the presence of hydrogen peroxide, transition metals and hydrogen peroxide are believed to play a key role in producing the residual effect of UV radiation through the formation of reactive species, for example, hydroxyl radical.
Chloride Removal from Recycled Cooling Water Using Ultra‐High Lime with Aluminum Process
Authors: Abdel‐Wahab Ahmed , Batchelor Bill
Published: September 2006

Chloride is a deleterious ionic species in cooling water systems because it promotes corrosion, and most of the scale and corrosion inhibitors are sensitive to chloride concentration in the water. Chloride can be removed from cooling water by precipitation as calcium chloroaluminate [Ca4Al2Cl2(OH)12]. A set of equilibrium experiments and one kinetic experiment were conducted to evaluate chloride removal using the ultra‐high lime with aluminum (UHLA) process and to characterize the equilibrium conditions of calcium chloroaluminate precipitation. A total of 48 batch‐equilibrium experiments were conducted on a 30 mM NaCl solution over a range of values for lime dose (0 to 200 mM) and sodium aluminate dose (0 to 100 mM). Experimental results showed that the UHLA process can remove chloride and that the formation of a calcium chloroaluminate solid phase is a reasonable mechanism that is able to adequately describe experimental results. An average value of the ion activity product of 10−94.75 was obtained and can be used as an estimate of the solubility product for Ca4Al2Cl2(OH)12.
Degradation of Methanethiol in a Continuously Operated Upflow Anaerobic Sludge‐Blanket Reactor
Authors: Sipma Jan , van Bree Robbie , Janssen Albert J. H. , Arena Blaise , Hulshoff Pol Look W. , Lettinga Gatze
Published: September 2006

The feasibility of anaerobic treatment of wastewater containing volatile organic sulfur compounds was investigated using biomass originating from an anaerobic wastewater treatment facility treating brewery wastewater. Interest focused mainly on the degradation of methanethiol (MT), an extremely volatile and malodorous sulfur compound. Formation of hydrogen sulfide from methanethiol, dimethyl sulfide (DMS), and dimethyl disulfide (DMDS) was observed. Batch experiments showed that methanethiol was predominantly used by methanogenic bacteria as the sole source of energy and carbon. Methane was formed on MT degradation, and in the presence of 2‐bromoethanesulfonic acid (BES), a specific inhibitor of methanogens, MT conversion was strongly inhibited. During the MT degradation, DMS and DMDS were the other primary compounds found. Relatively small quantities of DMS were present; whereas the DMDS concentrations could accumulate as a result of the relatively fast rate at which methanethiol autoxidizes in the presence of minor amounts of molecular oxygen. It was shown that DMS and DMDS could be biologically degraded, resulting in the formation of methane and hydrogen sulfide. In a continuous experiment using a laboratory‐scale upflow anaerobic sludge‐blanket (UASB) reactor with a volume of 2.0 L, the feasibility of anaerobic treatment of methanethiol was tested. The reactor was operated at a hydraulic residence time (HRT) of 6 hours, temperature of 30 °C, and pH of 7.3 to 7.6. The maximal MT conversion efficiency in the continuous experiment was reached after approximately 70 days and exceeded 97% at an influent concentration of 6 mM, corresponding to a MT loading rate of 25 mM/d. The specific MT degradation rate, as determined after 40 days of operation in the UASB, measured 1.1 ± 0.1 mM MT/g volatile suspended solids▪d. These results show that anaerobic treatment of MT‐containing waste streams is an interesting alternative for currently used physicochemical treatment methods.
Comparison of Various Measures of Microbial Growth Kinetics in Suspended and Biofilm Cultures During Biodegradation of Naphthalene
Authors: Shim Jeong Seop , Lewandowski Gordon A.
Published: September 2006

This research focused on measurement of bacterial growth rates and activities in suspended cultures and biofilms using Pseudomonas putida (ATCC 17484) for biodegradation of naphthalene. A comparison was made of the effect of three biomass measures: optical density, total cell protein, and living cell number on the calculated rate of naphthalene disappearance. Living cell number was determined by optimizing a fluorescent staining technique and using epifluorescence microscopy. All three techniques gave similar results in terms of the specific growth rates, and in all three there was a lag time between the disappearance of naphthalene and the appearance of biomass. This was most likely a consequence of the production of intermediate products detected in the chromatograms. Inclusion of a one‐hour lag time in the integrated Monod expression considerably improved the agreement between experimental and calculated values. However, further improvements to an understanding of the overall rate processes may require more detailed kinetics of the individual biochemical pathways.
Effects of Substrate and Oxygen Loading Rates on Gas‐Phase Toluene Removal in a Three‐Phase Biofilm Reactor
Authors: Yu Haibo , Kim Byung J. , Rittmann Bruce E.
Published: September 2006

A three‐phase, circulating‐bed biofilm reactor using macroporous carriers removed toluene from a gas stream continuously for more than six months. Three steady states were established with toluene loading rates varying from 0.030 to 0.059 mol/m2▪d. For each steady state, short‐term experiments evaluated the effects of toluene and oxygen loading rates. At least 99% of the biomass in the system was accumulated inside the carrier macropores, and the total biomass was proportional to the toluene loading rate. Toluene removal ranged from approximately 100 to 55%. The lower toluene removals were associated with oxygen limitation, which also resulted in the accumulation of an intermediate (3‐methylcatechol) and nontoluene chemical oxygen demand. The results suggest that excessive biomass accumulation hurt process performance by depleting oxygen within the biofilm because increased endogenous respiration consumed more oxygen, while increased biomass density may have slowed oxygen diffusion.
Investigating a Mechanistic Cause for Activated‐Sludge Deflocculation in Response to Shock Loads of Toxic Electrophilic Chemicals
Authors: Bott Charles B. , Love Nancy G.
Published: September 2006

It is hypothesized that a physiological bacterial stress response mechanism, called the glutathione‐gated potassium efflux system, is a significant contributor to activated‐sludge deflocculation caused by shock loads of toxic electrophilic chemicals. The results show significant potassium (K+) efflux from activated sludge flocs to the bulk liquid in response to sublethal (concentrations less than that required to reduce the specific oxygen uptake rate by 50%) shock loads of chloro2,4‐dinitrobenzene, N‐ethylmaleimide, 2,4‐dinitrotoluene, benzoquinone, and cadmium in a bench‐scale sequencing batch reactor system. Electrophile‐induced K+ efflux was correlated with significant deflocculation, as measured by an increase in effluent volatile suspended solids. The K+ efflux occurred immediately (within minutes) after toxin addition and preceded the observed increase in effluent turbidity. The transport of other cations, including sodium, calcium, magnesium, iron, and aluminum, either to or from the floc structure, was negligible as compared with K+ efflux, and cell lysis was determined to be minimal at the chemical shock loads applied. The current results are the first to suggest that activated‐sludge upset (i.e., deflocculation) may be caused by a specific protective stress response in bacteria.
Physical Enrichment of Polyphosphate‐Accumulating Organisms in Activated Sludge
Authors: Hung Chun‐Hsiung , Peccia Jordan , Zilles Julie L. , Noguera Daniel R.
Published: September 2006

Two methods that physically separate polyphosphate‐accumulating organisms (PAO) from other organisms in activated sludge were developed. The first method used 4'6‐diamidino‐2‐phenylindole dihydrochloride (DAPI) to selectively stain PAO. When excited with light at 340 nm, polyphosphate granules in DAPI‐stained cells fluoresce yellow while cells without polyphosphate fluoresce blue. This difference in fluorescent response was used to separate PAO from non‐PAO using flow cytometry. The second method consisted of a simple gradient centrifugation to physically separate PAO from non‐PAO based on their density differences. Both methods produced cell suspensions with an increased PAO concentration. From an average PAO concentration of approximately 14% in a full‐scale process, the DAPI–flow cytometry method produced sorted samples with PAO representing more than 70% of the total cells, while the density gradient method produced an approximate 43 to 48% PAO enrichment. The physical enrichment methods described herein should facilitate the identification and study of PAO that are relevant in full‐scale enhanced biological phosphorus removal processes.
Determination of the Inactivation Rate of Ascaris Eggs in Wastewater Stabilization Pond Sludge Using Dialysis Chambers and Sludge Cores
Authors: Nelson Kara L. , Darby Jeannie L.
Published: September 2006

The inactivation rate of Ascaris eggs was studied in the sludge layer of a primary, facultative wastewater stabilization pond located in Mexico City. Two independent methods, sludge cores and dialysis chambers, were used to determine the inactivation rates through which a comprehensive picture of the inactivation was gained. The dialysis chambers provided a detailed picture of the initial inactivation (14 months) at one location in the pond, whereas the sludge cores provided less precise information about the inactivation rate at several locations and over the entire lifetime of the pond (10 years). The inactivation curve was characterized by an initial lag phase, a period of roughly first‐order inactivation, and a tailing region. During the first year, 50 to 60% of the eggs were inactivated, after which the rate decreased. Although the observed, initial first‐order rate constant was greater than 0.002 d−1, the average, long‐term rate constant was closer to 0.001 d−1.
Microbiology of Enhanced Biological Phosphorus Removal in Aerated—Anoxic Orbal Processes
Authors: Zilles Julie L. , Peccia Jordan , Noguera Daniel R.
Published: September 2006

The traditional process for enhanced biological phosphorus removal (EBPR) in wastewater treatment involves an anaerobic zone followed by an aerobic zone. Although there is no strict anaerobic zone in aerated‐anoxic Orbal processes, phosphorus removal in excess of that required for cell growth does occur. The microbial ecology of polyphosphate‐accumulating organisms (PAO) in two full‐scale Orbal wastewater treatment plants was investigated using flow cytometry to physically separate PAO from non‐PAO and fluorescent in situ hybridization (FISH) to identify organisms. Although Candidatus Accumulibacter phosphatis, an uncultured organism associated with EBPR in acetate‐fed laboratory‐scale reactors, was detected, it did not seem to be the dominant PAO in these processes. Comparative FISH analyses of the activated sludge and the PAO‐rich subpopulation did not reveal the presence of a dominant group of PAO in these full‐scale plants. Rather, the analysis suggested that the operational characteristics of aerated‐anoxic processes might select for a diverse PAO community that is significantly different from that observed in acetate‐fed laboratory reactors or in traditional EBPR configurations.
The Activated Sludge Biomolecular Database
Authors: Lajoie C. A. , Sayler G. S. , Kelly C. J.
Published: September 2006

Tremendous advances have recently been made in the development of molecular tools for analysis of microbial populations in the environment. However, an appropriate scientific basis for quantification of new molecular data must exist to effectively use these tools toward increased understanding of complex waste treatment environments and implementation of corrective actions to maintain or improve system performance. In particular, molecular tools are gaining widespread use in the study of activated‐sludge microbial communities and have the potential to improve monitoring and control of wastewater treatment processes. The authors have created a Web‐accessible database, the Activated Sludge Biomolecular Database, which provides a scientific basis for interpreting activated‐sludge biomolecular information. The database achieves its goal by accumulating and disseminating a large body of knowledge relating the presence and quantity of specific biomolecules to process design, operating conditions, and wastewater characteristics.
The Reaction Mechanisms and Kinetics of Removing Azo Reactive Dye by Indirect Photolysis Approaches
Authors: Tsui S. M. , Chu W.
Published: September 2006

The photodegradation of azo reactive dye (RR2) in the presence of acetone (ACE) or triethylamine (TEA) via indirect photolysis was investigated. Photolytic experiments were conducted in a merry‐goround photoreactor with 253.7‐nm monochromatic UV lamps. The photodegradation of RR2 in aqueous ACE or TEA solution was found to be kinetically controlled by pseudo‐first‐ and zero‐order kinetics, respectively. Typically, the photodegradation reaction is more favorable at higher pH. In the presence of TEA, the rate enhancement primarily is a result of the electron transfer from TEA to RR2 and results in the photoreduction of dye chromophore. Photosensitization is likely the dominant mechanism in the presence of ACE. With respect to the decoloration rate, ACE proved to be a promising rate enhancer at elevated concentrations, and the solution color faded rapidly within 5 minutes of retention time. The photodecoloration of RR2 was found to co‐occur with photodechlorination and was followed by photodesulfonation at a later stage in which the mineralized end products, including hydrogen, chloride, and sulphorate ions, were detected in approximately stoichiometric amounts.
Changing Mesophilic Wastewater Sludge Digestion into Thermophilic Operation at Terminal Island Treatment Plant
Authors: Iranpour R. , Cox H. H. J. , Shao Y. J. , Moghaddam O. , Kearney R. J. , Deshusses M. A. , Stenstrom M. K. , Ahring B. K.
Published: September 2006

This paper describes the progress up to June 2000 for thermophilic digestion of wastewater sludge at the Los Angeles, California, Bureau of Sanitation's Terminal Island Treatment Plant. The development of the microorganism culture has followed a course similar to that seen at other successful plants for establishment of a stable, well‐balanced thermophilic culture in a large digester, but at an accelerated pace. This study began with rapid heating, increasing the temperature of the 4500 m3 (1.2 mil. gal) digester to the target temperature of 55 °C at approximately 3 °C/d. A method of feeding to maximize the rate of culture development was used as feeding accelerated to approximately 400 m3/d (0.1 mgd). An initial rise of acid concentration (primarily acetate) was seen. Within two weeks, acid concentration declined and stabilized, indicating that acidogenic and methanogenic microbial communities came into balance. Coliform data indicate that digester disinfection was stably effective from the middle of April. The salmonella tests done to date satisfy the U.S. Environmental Protection Agency (U.S. EPA) class A specification. Testing with helminth ova and enteric viruses before and after the digester shows satisfaction of class A standard for those organisms. The present combination of low volatile fatty acids and low hydrogen sulfide is good news for odor control. The data show increases in volatile solids destruction and estimated gas production, compared with the previous mesophilic operation; however, large uncertainties have been calculated from the data. As the digester is now operating successfully at the current feed rate, there seems to be no barriers to processing the entire sludge production of the plant. Other results indicate that the U.S. EPA requirements for exceptional quality class A biosolids are likely to be achieved.
Electroadsorption of Acilan Blau Dye from Textile Effluents by Using Activated Carbon–Perlite Mixtures
Authors: Koparal A. S. , Yavuz Y. , Bakir Öğütveren Ü.
Published: September 2006

The feasibility of the removal of dye stuffs from textile effluents by electroadsorption has been investigated. An activated carbon–perlite mixture with a ratio of 8:1 for bipolarity has been used as the adsorbent. Conventional adsorption experiments have also been conducted for comparison. A bipolar trickle reactor has been used in the electroadsorption experiments. The model wastewater has been prepared by using acilan blau dye. Initial dye concentration, bed height between the electrodes, applied potential, flowrate, and the supporting electrolyte concentration have been examined as the parameters affecting the removal efficiency. A local textile plant effluent has been treated in the optimum values of these parameters obtained from the experimental studies. Adsorption kinetics and the amount of adsorbent required to reach the maximum removal efficiency have also been investigated and mass‐transfer coefficients have been calculated for adsorption and electroadsorption. The results showed that a removal efficiency of up to 100% can be achieved with energy consumption values of 1.58 kWh/m3 of wastewater treated. However, energy consumption decreases to 0.09 kWh/m3 if an exit dye concentration of 4.65 mg/L is accepted. It can be concluded from this work that this method combines all of the advantages of the activated‐carbon adsorption and electrolytic methods for the removal of dyes from wastewater.
Giardia Cysts in Tertiary‐Treated Wastewater Effluents: Are They Infective?
Authors: Garcia April , Yanko William , Batzer Glenda , Widmer Giovanni
Published: September 2006

The infectivity of Giardia lamblia cysts recovered in primary‐ and tertiary‐treated wastewater reclamation plant effluents was assessed in Mongolian gerbils (Meriones unguiculatus). Infections in gerbils inoculated with cysts from primary effluent concentrates demonstrated the presence of infectious G. lamblia cysts. No infectious cysts were detected by this method in concentrates of tertiary‐treated effluents. This study found that determination of cyst concentrations without viability or infectivity assessment may significantly overestimate the potential health risks associated with protozoan cysts in tertiary‐treated wastewater effluents.
The Sonolytic Destruction of Methyl tert‐Butyl Ether Present in Contaminated Groundwater
Authors: Hung Hui‐Ming , Kang Joon‐Wun , Hoffmann Michael R.
Published: September 2006

Ultrasonic irradiation in the presence of ozone was used to efficiently eliminate methyl tert‐butyl ether (MTBE) from groundwater. The sonolytic degradation of MTBE was investigated in three different reactor configurations and frequencies: vibrating‐plate reactor (VPR, 358 kHz), near‐field acoustical processor (NAP 20 and 16 kHz), and radial‐tube resonator (RTR, 20 kHz). The sonochemical reactors can be ordered in terms of their efficiency with respect to the degradation of MTBE in the following way: VPR > RTR > NAP. The higher elimination rates of MTBE in groundwater by combined ultrasound–ozone systems are attributed to the effective conversion of ozone to the OH radical, even in the presence of high alkalinity. Carbonate radicals, which were formed from the oxidation of bicarbonate by hydroxyl radicals, are shown to react with MTBE via a hydrogen‐atom abstraction pathway. Methyl‐tert‐butyl ether was also rapidly eliminated from the groundwater underlying a major international airport by direct chemical oxidation with a mixture of hydrogen peroxide and ozone.
Quantification of Nitrosomonas oligotropha and Nitrospira spp. Using Competitive Polymerase Chain Reaction in Bench‐Scale Wastewater Treatment Reactors Operating at Different Solids Retention Times
Authors: Dionisi H. M. , Layton A. C. , Robinson K. G. , Brown J. R. , Gregory I. R. , Parker J. J. , Sayler G. S.
Published: September 2006

The effect of solids retention time (SRT) on ammonia and nitrite‐oxidizing bacteria was measured by Nitrosomonas oligotropha‐like ammonia monooxygenase A and Nitrospira 16S rDNA competitive polymerase chain reaction assays in a complete‐mix, bench‐scale, activated‐sludge system. During steady‐state operation, nitrification was complete in the 20‐ and 10‐day SRT reactors, nearly complete in the 5‐day SRT reactor, and incomplete in the 2‐day SRT reactor (76% ammonia oxidation and 85% nitrite oxidation). Total microbes, measured by dot‐blot hybridizations, ranged from 3 × 1011 to 3 × 1012 cells/L, and increased with increasing SRTs. The concentration of the ammonia‐oxidizer N. oligotropha dropped 100‐fold from the 20‐day SRT (5 × 109 cells/L) to the 2‐day SRT (≤4 × 107 cells/L). Thus, N. oligotropha became a much smaller fraction of the total biomass in the poorly performing 2‐day SRT reactor. The concentration of Nitrospira cells also decreased (10‐fold) as the SRT was reduced from 20 days to 2 days. However, the number of Nitrospira cells was always greater than the number of N. oligotropha cells measured in each reactor (10‐ to 60‐fold). While Nitrospira comprised 1 to 2% of the biomass, N. oligotropha represented only 0.04 to 0.27% of the total population. This low percentage suggests that N. oligotropha was not a dominant ammonia oxidizer in the bench‐scale systems.
Immune network control for stigmergy based foraging behaviour of autonomous mobile robots
Authors: Tsankova Diana , Georgieva Velichka , Zezulka Frantisek , Bradac Zdenek
Published: September 2006

The paper presents a series of experiments in a simulated environment where two autonomous mobile robots gather randomly distributed objects and cluster them on a pile. The co‐ordination of the robots' movements is achieved through stigmergy (an indirect form of communication through the environment). The random moves, necessary for stigmergy based foraging behaviour, make the task solution a time consuming process. In order to speed up the foraging behaviour, the immune network robot control is proposed. Stigmergic principles are coded in two artificial immune networks—for a collision free goal following behaviour and for an object picking up/dropping behaviour. Simulations confirm the improved performance of the foraging behaviour under the proposed immune network control. Copyright © 2006 John Wiley & Sons, Ltd.
A verified hierarchical control architecture for co‐ordinated multi‐vehicle operations
Authors: Borges de Sousa João , Johansson Karl H. , Silva Jorge , Speranzon Alberto
Published: September 2006

A layered control architecture for executing multi‐vehicle team co‐ordination algorithms is presented along with the specifications for team behaviour. The control architecture consists of three layers: team control, vehicle supervision and maneuver control. It is shown that the controller implementation is consistent with the system specification on the desired team behaviour. Computer simulations with accurate models of autonomous underwater vehicles illustrate the overall approach in the co‐ordinated search for the minimum of a scalar field. The co‐ordinated search is based on the simplex optimization algorithm. Copyright © 2006 John Wiley & Sons, Ltd.
Fault diagnosis of a simulated industrial gas turbine via identification approach
Authors: Simani S.
Published: September 2006

In this paper, a model‐based procedure exploiting the analytical redundancy principle for the detection and isolation of faults on a simulated process is presented. The main point of the work consists of using an identification scheme in connection with dynamic observer and Kalman filter designs for diagnostic purpose. The errors‐in‐variables identification technique and output estimation approach for residual generation are in particular advantageous in terms of solution complexity and performance achievement. The proposed tools are analysed and tested on a single‐shaft industrial gas turbine MATLAB/SIMULINK® simulator in the presence of disturbances, i.e. measurement errors and modelling mismatch. Selected performance criteria are used together with Monte‐Carlo simulations for robustness and performance evaluation. The suggested technique can constitute the design methodology realising a reliable approach for real application of industrial process FDI. Copyright © 2006 John Wiley & Sons, Ltd.
HDDD2 is a familial frontotemporal lobar degeneration with ubiquitin‐positive, tau‐negative inclusions caused by a missense mutation in the signal peptide of progranulin
Authors: Mukherjee Odity , Pastor Pau , Cairns Nigel J. , Chakraverty Sumi , Kauwe John S. K. , Shears Shantia , Behrens Maria I. , Budde John , Hinrichs Anthony L. , Norton Joanne , Levitch Denise , Taylor‐Reinwald Lisa , Gitcho Michael , Tu P.‐H. , Tenenholz Grinberg Lea , Liscic Rajka M. , Armendariz Javier , Morris John C. , Goate Alison M.
Published: September 2006

Objective

Familial autosomal dominant frontotemporal dementia with ubiquitin‐positive, tau‐negative inclusions in the brain linked to 17q21‐22 recently has been reported to carry null mutations in the progranulin gene (PGRN). Hereditary dysphasic disinhibition dementia (HDDD) is a frontotemporal dementia with prominent changes in behavior and language deficits. A previous study found significant linkage to chromosome 17 in a HDDD family (HDDD2), but no mutation in the MAPT gene. Longitudinal follow‐up has enabled us to identify new cases and to further characterize the dementia in this family. The goals of this study were to develop research criteria to classify the different clinical expressions of dementia observed in this large kindred, to identify the causal mutation in affected individuals and correlate this with phenotypic characteristics in this pedigree, and to assess the neuropathological characteristics using immunohistochemical techniques.

Methods

In this study we describe a detailed clinical, pathological and mutation analysis of the HDDD2 kindred.

Results

Neuropathologically, HDDD2 represents a familial frontotemporal lobar degeneration with ubiquitin‐positive, tau‐negative inclusions (FTLD‐U). We developed research classification criteria and identified three distinct diagnostic thresholds, which helped localize the disease locus. The chromosomal region with the strongest evidence of linkage lies within the minimum critical region for FTLD‐U. Sequencing of each exon of the PGRN gene led to the identification of a novel missense mutation, Ala‐9 Asp, within the signal peptide.

Interpretation

HDDD2 is an FTLD‐U caused by a missense mutation in the PGRN gene that cosegregates with the disease and with the disease haplotype in at‐risk individuals. This mutation is the first reported pathogenic missense mutation in the signal peptide of the PGRN gene causing FTLD‐U. In light of the previous reports of null mutations and its position in the gene, two possible pathological mechanisms are proposed: (1) the protein may accumulate within the endoplasmic reticulum due to inefficient secretion; and (2) mutant RNA may have a lower expression because of degradation via nonsense‐mediated decay. Ann Neurol 2006;60:314–322
Adipokinetic hormone‐induced mobilization of fat body triglyceride stores in Manduca sexta: Role of TG‐lipase and lipid droplets
Authors: Patel Rajesh T. , Soulages Jose L. , Arrese Estela L.
Published: September 2006

Triglycerides (TG) stores build up in the insect fat body as lipid droplets at times of excess of food. The mobilization of fat body triglyceride (TG) is stimulated by adipokinetic hormones (AKH). The action of AKH involves a rapid activation of cAMP‐dependent protein kinase (PKA). Recent in vitro studies have shown that PKA phosphorylates and activates the TG‐lipase substrate, the lipid droplets. Conversely, purified TG‐lipase from Manduca sexta fat body is phosphorylated by PKA in vitro but is not activated. This study was directed to learn whether or not AKH promotes a change in the state of phosphorylation of the lipase in vivo, and what are the relative contributions of cytosol and lipid droplets to the overall increase of lipolysis triggered by AKH. TG‐lipase activity of fat body cytosols isolated from control and AKH‐treated insects was determined against the native substrate, in vivo [3H]‐TG radiolabeled lipid droplets, obtained from control and AKH‐treated insects. The lipase activity of the system composed of AKH‐cytosol and AKH‐lipid droplets (11.1 ± 2.1 nmol TG/min‐mg) was 3.1‐fold higher than that determined with control cytosol and lipid droplets (3.6 ± 0.5 nmol TG/min‐mg). Evaluation of the role of AKH‐induced changes in the lipid droplets on lipolysis showed that changes in the lipid droplets are responsible for ˜70% of the lipolytic response to AKH. The remaining 30% appears to be due to AKH‐dependent changes in the cytosol. However, the phosphorylation level of the TG‐lipase was unchanged by AKH, indicating that phosphorylation of the TG‐lipase plays no role in the activation of lipolysis induced by AKH. Arch. Insect Biochem. Physiol. 63:73–81, 2006. © 2006 Wiley‐Liss, Inc.