Showing papers on "Trickling filter published in 1998"
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TL;DR: In this article, synthetic fibers were identified using polarized light microscopy, which provided a simple, rapid method for determining the presence or absence of municipal sewage sludge or its products.
Abstract: Because of concerns regarding health, safety, and aesthetics, a test that identifies the presence of sewage sludge or its products (biosolids) in commercial materials such as soil conditioners and composts would be useful. This test could also trace the effluent plume from a sewage treatment plant. We have discovered that synthetic fibers serve as such an indicator. Synthetic fibers are abundant in sludge, sludge products, and sewage treatment plant effluents. The fibers evidently are introduced from clothes-washing machines and survive the sewage treatment process. Synthetic fibers were identified using polarized light microscopy, which provided a simple, rapid method for determining the presence or absence of municipal sewage sludge or its products. False positives or false negatives have not occurred with any of the materials examined so far. We also monitored synthetic fibers in surface sediments of Huntington Harbor, Long Island, NY, a harbor receiving the effluent from a trickling filter sewage treatment plant. Fibers generally decrease in size and abundance with distance from the source. In Oyster Bay Harbor, Long Island, an advanced sewage treatment plant is operated with a final microfiltration step. Synthetic fibers are less abundant in the sediments of this harbor.
126 citations
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TL;DR: The study failed to show any relationship for either type of filter between the hydraulic loading rate and the nitrification rate at hydraulic loading rates between 469 and 1231 m3 m−2 day−1.
112 citations
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TL;DR: It was found that the continuous operational mode leads to higher percentage of manganese removal but lower throughput rates when compared with a sequencing batch reactor operation with the same feed concentration and retention time.
111 citations
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TL;DR: Experimental results showed that as biomass accumulates in the reactor, the available area for the contaminant to diffuse into the biofilm decreases causing a drop in removal efficiency.
Abstract: Although biofiltration is a firmly established technology for the control of emissions of volatile organic compound (VOCs), more fundamental research is still needed. This work uses a mathematical model describing the dynamic physical and biological processes occurring in a packed trickle-bed air biofilter to analyze the relationship between biofilter performance, biomass accumulation in the reactor, and mathematical description of the packed bed porous media. In this study a biofilter packed with pelletized support media was used to treat toluene achieving removal efficiencies over 99% and 97% for 4.1 and 6.2 kg COD/m{sup 3} day toluene loading, respectively. Experimental results showed that as biomass accumulates in the reactor, the available area for the contaminant to diffuse into the biofilm decreases causing a drop in removal efficiency. This effect is specially important for biofilters where there is a high degree of biomass accumulation that significantly affects biofilter performance. In response to these observations, a new approach for the calculation of the biofilm specific surface area of the reactor as a function of biomass growth was developed. Three models of the reactor porous medium were analyzed. The medium was represented as a bed of equivalent spheres in the first model, as an equivalentmore » set of parallel pipes in the second model, and as an equivalent set of flat parallel plates in the third model. The first two models, spheres and pipes, were proven superior in their ability to explain the system performance. The effect of contaminant solubility on biofilter performance was also analyzed.« less
109 citations
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TL;DR: In this paper, an environmental monitoring study was conducted to assess the removal of alkyl ethoxylate sulfates (AESs), AEs, and LASs during wastewater treatment.
Abstract: An environmental monitoring study was conducted to assess the removal of alkyl ethoxylate sulfates (AESs), alcohol ethoxylates (AEs), and linear alkylbenzene sulfonates (LASs) during wastewater treatment. Samples were obtained from six trickling filter and four activated sludge treatment plants located in the midwestern United States. The average removal rates for AESs, AEs, and LASs in activated sludge treatment were 98, 97, and >99%, respectively. Lower and more variable removal rates were observed at trickling filter treatment plants with average values of 83, 90, and 82% for AESs, AEs, and LASs, respectively. Using average influent concentrations and removal rates, the predicted exposure concentrations for these surfactants in U.S. receiving waters immediately below treatment plant outfalls were less than their corresponding biological predicted no-effect concentrations in greater than 98% of the locations under low-flow conditions.
105 citations
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TL;DR: In this paper, a laboratory-scale anaerobic reactor, in which the bottom two-thirds were occupied by a sludge blanket and the upper one-third by submerged small cubes of polyurethane foam, was evaluated for the treatment of slaughterhouse wastewater.
74 citations
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TL;DR: Analysis of the data obtained has shown that the model sufficiently explains and predicts the ammonium removal rate of a wide range of commercial trickling filters, and is used to optimise performance of existing biofilters in terms of ammonium levels achieved and pumping costs.
67 citations
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TL;DR: The results of a linear alkylbenzene sulphonate (LAS) monitoring exercise carried out during August and September, at six different trickling filter sewage treatment plants in the Aire and Calder catchments in the UK are described.
66 citations
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65 citations
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TL;DR: In this paper, an anaerobic filter (5·8 m3) operated at ambient temperature was used to treat brewery wastewater, and the results showed that, when the ambient temperature is high, an AN can operate in the mesophilic range and was used for treating brewery wastewater successfully.
27 citations
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TL;DR: The Rya WWTP in Goteborg, Sweden is a highly loaded activated sludge plant which has been upgraded to remove nitrogen and to increase the biologically treated flow by 33% to reduce bypassing as mentioned in this paper.
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TL;DR: The novel trickling fibrous-bed bioreactor developed for biofiltration to remove pollutants present in contaminated air had a fast response to process condition changes and was stable for long-term operation; no degeneration or clogging of the biofilter was encountered during the 3-month period studied.
Abstract: A novel trickling fibrous-bed bioreactor was developed for biofiltration to remove pollutants present in contaminated air. Air containing benzene as the sole carbon source was effectively treated with a coculture of Pseudomonas putida and Pseudomonas fluorescens immobilized in the trickling biofilter, which was wetted with a liquid medium containing only inorganic mineral salts. When the inlet benzene concentration (C gi ) was 0.37 g/m 3 , the benzene removal efficiency in the biofilter was greater than 90% at an empty bed retention time (EBRT) of 8 min or a superficial air flow rate of 1.8 m 3 /m 2 .h. In general, the removal efficiency decreased but the elimination capacity of the biofilter increased with increasing the inlet benzene concentration and the air (feed) flow rate. It was also found that the removal efficiency decreased but the elimination capacity increased with an increase in the loading capacity, which is equal to the inlet concentration divided by EBRT. The maximum elimination capacity achieved in this study was ∼11.5 g/m 3 .h when the inlet benzene concentration was 1.7 g/m 3 and the superficial air flow rate was 3.62 m 3 /m 2 .h. A simple mathematical model based on the first-order reaction kinetics was developed to simulate the biofiltration performance. The apparent first order parameter K 1 in this model was found to be linearly related to the inlet benzene concentration (K 1 =4.64-1.38 C gi ). The model can be used to predict the benzene removal efficiency and elimination capacity of the biofilter for benzene loading capacity up to ∼30 g/m 3 .h. Using this model, the maximum elimination capacity for the biofilter was estimated to be 12.3 g/m 3 .h, and the critical loading capacity was found to be 14 g/m 3 .h. The biofilter had a fast response to process condition changes and was stable for long-term operation; no degeneration or clogging of the biofilter was encountered during the 3-month period studied. The biofilter also had a relatively low pressure drop of 750 Pa/m at a high superficial air flow rate of 7.21 m 3 /m 2 .h, indicating a good potential for further scale up for industrial applications.
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TL;DR: In this paper, the trickling filter/solids contact (TF/SC) process was tested for consistent nitrification in colder climates where average monthly wastewater temperatures fall to 9 to 10°C.
Abstract: It is anticipated that the West Windsor Pollution Control Plant (WWPCP) (Windsor, Ontario, Canada) will be required to be upgraded from its current chemical primary treatment to full secondary treatment, with phosphorus removal maintained. A steering committee established effluent design objectives for effluent suspended solids and total 5-day biochemical oxygen demand of 15 mg/L, total phosphorus of 0.5 mg/L, and ammonia-nitrogen of 3 mg/L. Four processes were tested; among these, the trickling filter/solids contact (TF/SC) process had not been tested previously for consistent nitrification in colder climates where average monthly wastewater temperatures fall to 9 to 10°C. A novel TF/SC treatment scheme was identified that took advantage of the low biochemical oxygen demand of the WWPCP's chemical primary effluent and used higher density cross-flow media than had previously been used in the TF/SC process to achieve nitrification. In initial testing, the TF/SC process nitrified successfully but failed to meet the other objectives. A detailed diagnosis showed that the best process configuration had not been tested and that the pilot design was flawed in several respects. The inclusion of a sludge reaeration tank, the substitution of a flocculator-clarifier for a conventional scraper clarifier, and the elimination of head losses causing excessive floc breakup corrected the problem. In testing over a year-long period, the TF/SC process consistently met the target objectives, moving it up from fourth place to a tie with the other first-ranked process, the biological aerated filter (BAF). Capital costs were found to be lower than for the activated-sludge process and the BAF processes.
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TL;DR: In this paper, the removal of mono-chlorobenzene (m-CB) vapors from air streams in a biotrickling filter unit was studied under various operating conditions concerning inlet m-CB concentration (Cgi), air residence time (τ), liquid recirculation rate (Q), pH, and frequency of medium replenishment.
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TL;DR: A trickling filter packed with PVC 16 mm Raschig rings was used to study the degradation of toluene in a polluted air stream, by means of a bacterial biofilm of Pseudomonas putida ATCC 17484.
Abstract: A trickling filter packed with PVC 16 mm Raschig rings was used to study the degradation of toluene in a polluted air stream, by means of a bacterial biofilm of Pseudomonas putida ATCC 17484. A polluted stream was simulated by blending air with a controlled amount of toluene. The mixing was accomplished in a special mixing chamber designed for that purpose. Induction of the enzymes of the toluene degradative pathway and adaptation of the inoculum were done in batch cultures with minimum mineral media and phenol. The continuous experiments were monitored by mass spectrometry for the quantification of the various gases and of toluene removal. A 94% toluene removal was achieved with contacting times above one minute and toluene concentrations up to 400 ppm.
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TL;DR: In this article, a cross flow medium trickling filter was used to evaluate the performance of a synthetic wastewater in terms of its nitrification performance in three different hydraulic loading rates 5, 9 and 13␣m3/m2 · d under various influent ammonium concentrations.
Abstract: The nitrification performance of a synthetic wastewater was investigated in a cross flow medium trickling filter. The attachment of biomass on packing medium was studied. The reactor was operated continuously for three different hydraulic loading rates 5, 9 and 13␣m3/m2 · d under various influent ammonium concentrations. The maximum specific surface nitrification rate was about 1.21 g/m2 · d. There was a good agreement between actual and predicted alkalinity consumption. The ammonium conversion along the filter depth was also investigated. The external surface of the nitrifying biofilm was captured by scanning electron microscope. The results are found to be satisfactory.
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TL;DR: In this paper, the authors defined the removal rate of indicator microorganisms on various types of trickling filters with regard to the influence of magnetic stream and electric current passage, and the effectiveness of microorganism adsorption onto the media.
Abstract: The objective of this study was to define the removal rate of the indicator microorganisms on various types of trickling filters with regard to the influence of: magnetic stream and electric current passage, and the effectiveness of microorganism adsorption onto the media. The hydraulic loading in the first eight variants were changing, while variants 9-14 were peformed at a constant loading. The study results have indicated a positive influence of the extra energy sources, i. e. a magnetic stream and electric current on the process of indicatory microorganism removal from waste water.
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TL;DR: In this paper, a low-tech low-cost treatment of municipal sewage is described, which is based on a ponding process followed by a trickling filter, where micro-algae produced in stabilization ponds are removed in the TF.
Abstract: The system offering low-tech low-cost treatment of municipal sewage is described. It is based on a ponding process followed by a trickling filter (TF). Micro-algae produced in stabilization ponds are removed in the TF. It is suggested that micro-algae contribute to biofilm production and organic load reduction in the TF.
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TL;DR: In this paper, post treatment of effluents from heterotrophic groundwater denitrification fluidized bed reactors (FBR) designed to achieve drinking water quality has been investigated.
Abstract: Post treatment of effluents from heterotrophic groundwater denitrification fluidized bed reactors (FBR) designed to achieve drinking water quality has been investigated. The denitrification process adds to the dissolved organic compounds, biomass and bacteria in the effluent. They are also lacking dissolved oxygen. Effluents from the process were treated in combined post treatment processes based on either a trickling filter and sedimentation unit (‘TF combination’) or contact flocculation (‘CF combination’). Both processes were followed by sand filtration, granular activated carbon (GAC) and chlorination. Results regarding total suspended solids (TSS) and turbidity removal showed an advantage to the ‘CF combination’, and the target turbidity (NTU <1) was always achieved when the alum dose was 10 or 20 mg l−1. Backwash of the sand filter and GAC column was required after 27 h of operation (average value). An average total reduction in dissolved organic carbon (DOC) of 40% was observed with a final DOC of 3.5–4 mg L−1. Most of the removal of the DOC occurred in the sand filter (28%), while the GAC contribution was smaller (18%). No regrowth potential was observed using the Werner method when a pure culture of Pseudomonas fluorescens P17 was used as inoculum in samples of chlorinated effluent (post chlorination). When a mixed culture of indigenous bacteria was used as inoculum, a high regrowth potential was observed. Installing an additional chlorination unit before the sand filter column (pre and post chlorination) resulted in effluent with no regrowth potential for both Pseudomonas fluorescens P17 and indigenous bacteria.
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TL;DR: In this paper, the authors proposed a three-stage system in which excess sludge from a high loaded activated sludge plant is used as carbon source and as source of denitrifiers.
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01 Jan 1998
TL;DR: In this article, chemical precipitation was evaluated for phosphorus removal on trickling filter plants to assess suitability for meeting the requirements of the EC Urban Wastewater Treatment Directive, and pre-, simultaneous and post-precipitation options were all shown to be capable of meeting the 2mg/l standard.
Abstract: Chemical precipitation was evaluated for phosphorus removal on trickling filter plants to assess suitability for meeting the requirements of the EC Urban Wastewater Treatment Directive. Pre-, simultaneous and post-precipitation options have all been shown to be capable of meeting the 2mg/l standard. Pre- and post-precipitation options can meet the 1mg/l standard. For the lower standard careful attention needs to be paid to the rapid mixing and subsequent flocculation of the coagulant. The phosphorus solubility equilibrium has been shown to be an important source of additional load from the primary settlement tanks if they are used for sludge storage.
01 Jan 1998
TL;DR: The aim of this research was to investigate the changes in microfauna during a typical operating cycle and the potential of protozoa to act as indicators of the operational phase and to achieve nitrification/denitrification.
Abstract: The use of the microfauna analysis to estimate both the quality of the effluent and the performance of the treatment plant is becoming more and more common. The importance of protozoan population in biological wastewater treatment systems has been widely studied for a number of treatment options, such as the activated sludge system, trickling filter systems and rotating biological contactors. However, only a few studies were published on protozoan population in sequencing batch reactors (SBR). The aim of this research was to investigate the changes in microfauna during a typical operating cycle and the potential of protozoa to act as indicators of the operational phase. The SBR was operated over a 10 months experimental period with the purpose of achieving nitrification/denitrification. The inoculum was mainly composed by a sample of mixed liquor from the aerated tank of a municipal wastewater treatment plant. The feed was a brewery wastewater after anaerobic pre-treatment. During the last 10 days, microscopic analysis of the reactor contents was performed throughout each cycle and protozoa were identified. At this time, the operating cycle consisted of a long aerated period followed by an anoxic phase. The dissolved oxygen (DO) was regulated by on-off control of the air flow. During the aerated period (DO=3-4 mg/L) crawling and attached ciliates were the predominant protozoa in the system. With the decrease of the DO concentration throughout the unaerated phase, these species showed a reduction of 40% and the appearance of free swimming ciliates and flagellated protozoa could be observed (Figure 1), indicating a poorly aerated sludge. Crawling and attached ciliates always re-established themselves as the aerobic conditions took place again, indicating that the cyclic operations had no detrimental effect on protozoa. The presence of Vaginicola sp., a common specie in nitrifying activated sludge systems, was often observed.
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01 Jan 1998-Journal of Environmental Science and Health Part A-toxic\/hazardous Substances & Environmental Engineering
TL;DR: In this paper, a system consisting of an aerated packed reactor (DAPR) followed by inclined tube settler (ITS) was tried to overcome the difficulties for the above mentioned wastes.
Abstract: Conventional biological treatment of intermittently flowing wastewaters is one of the significant problems of regions having seasonal activities. A system consisting of an downflow aerated packed reactor (DAPR) followed by inclined tube settler (ITS) was tried to overcome the difficulties for the above mentioned wastes. The DAPR‐ITS system can be regarded as a combination of activated sludge and trickling filter process followed by a high rate sedimentation unit (ITS). Three different no‐feed periods ranging from 3 to 26 weeks were used to characterize the off‐season activities. After this no‐feed period the system was started using different flow rates. The performance of the system was evaluated using chemical oxygen demand (COD), biochemical oxygen demand (BOD), nitrogen (N), phosphate (P) and total suspended solids (TSS) parameters. The results showed that DAPR‐ITS achieved about 80 % COD removal efficiency from the time of starting the system and reached steady state conditions within a few ...