Showing papers on "Trickling filter published in 1995"
TL;DR: In this paper, a selection of aerobic biofilm reactors and activated sludge plants were investigated for the presence of methane producing bacteria (MPB) and sulfate reducing bacteria (SRB).
110 citations
TL;DR: In this article, Artificial Neural Networks (ANN) are used as an alternative function approximation tool for predicting the performance of trickling filter treatment process in a municipal wastewater treatment plant, Solon, Ohio, USA, which uses a trickling filtering followed by an activated sludge process.
Abstract: Artificial neural networks (ANN) are used as an alternative function approximation tool for predicting the performance of trickling filter treatment process in a municipal wastewater treatment plant, Solon, Ohio, USA, which uses a trickling filter followed by an activated sludge process. The treatment plant had an average monthly inflow flow rate of 2.92 mgd (million gallons per day). The average raw, settled, and final BOD (biochemical oxygen demand) was 449, 235 and 4.8 mg/l, respectively, while the corresponding value for TSS (total suspended solids) was 296, 131, and 6.1 mg/l. The overall removal efficiency for BOD and TSS was 98.93 per cent and 97.95 per cent respectively. The best ANN model for predicting the trickling filter effluent BOD and TSS has a prediction error of 31.45 per cent and 32.54 per cent respectively. The number of input variables, as well as number of nodes in hidden layer seemed not to have a definite effect on the prediction error for the ANN model. The prediction errors obtaine...
86 citations
TL;DR: A concrete fish culture unit (50 m3) with common carp at an initial density of 20 kg m−3 was operated on a semi-closed mode with a minimum of fresh water addition (3 m3 day−3) as discussed by the authors.
74 citations
TL;DR: In this paper, the removal of toluene from waste gas was studied in a trickling biofilter, where a high level of water recirculation was maintained in order to keep the liquid phase concentration constant and to achieve a high degree of wetting.
Abstract: The removal of toluene from waste gas was studied in a trickling biofilter. A high level of water recirculation (4.7 m h−1) was maintained in order to keep the liquid phase concentration constant and to achieve a high degree of wetting. For loads in the range from 6 to 150 g m−3 h−1 the maximum volumetric removal rate (elimination capacity) was 35±10 g m−3 h−1, corresponding to a zero order removal rate of 0.11±0.03 g m−2 h−1 per unit of nominal surface area. The surface removal was zero order above the liquid phase concentrations of approximately 1.0 g m−3, corresponding to inlet gas concentrations above 0.7–0.8 g m−3. Below this concentration the surface removal was roughly of first order. The magnitude of the first order surface removal rate constant, k1A
, was estimated to be 0.08–0.27 m h−1 (k1A
a=24–86 h−1). Near-equilibrium conditions existed in the gas effluent, so mass transfer from gas to liquid was obviously relatively fast compared to the biological degradation. An analytical model based on a constant liquid phase concentration through the trickling filter column predicts the effluent gas concentration and the liquid phase concentration for a first and a zero order surface removal. The experimental results were in reasonable agreement with a very simple model valid for conditions with an overall removal governed by the biological degradation and independent of the gas/liquid mass transfer. The overall liquid mass transfer coefficient, KLa, was found to be a factor 6 higher in the system with biofilm compared to the system without. The difference may be explained by: 1. Difference in the wetting of the packing material, 2. Mass transfer occurring directly from the gas phase to the biofilm, and 3. Enlarged contact area between the gas phase and the biofilm due to a rough biofilm surface.
64 citations
TL;DR: In this article, a 2-year pilot study was conducted by the City of Malmo, Sweden, to determine the maximum capacity of existing trickling filters when converted from carbonaceous duty to nitrification duty.
Abstract: A 2-year pilot study was conducted by the City of Malmo, Sweden, to determine the maximum capacity of existing trickling filters when converted from carbonaceous duty to nitrification duty. Operating variables examined included a comparison of alternating two-stage to single-stage operation, flushing intensity, and predator control techniques. Distributor speed control had only a small effect on nitrification efficiency, and motorized distributors are not required in this application. Two-stage operation in an alternating mode provided for higher nitrification rates and lower effluent ammonia values than in single-stage operation. A nitrification model was used to analyze reaction rate data. The analysis showed that alternating two-stage operation mitigated the suppressing effect of influent suspended solids, resulting in enhanced nitrification rates. The filter macrofauna were dominated by worms rather than filter flies, so that regular filter flooding did not enhance nitrification rates.
37 citations
TL;DR: In this paper, the degradation of a commercial linear alkylbenzenesulfonate (LAS) surfactant was examined kinetically in a trickling filter, which allowed simultaneous chemical determinations in the aqueous phase (e.g., DOC) and in the gas phase (CO{sub 2}).
Abstract: The degradation of a commercial linear alkylbenzenesulfonate (LAS) surfactant was examined kinetically in a trickling filter, which allowed simultaneous chemical determinations in the aqueous phase (e.g., DOC) and in the gas phase (CO{sub 2}). About 60% of the carbon applied as LAS was released as CO{sub 2}, whereas 15% remained as DOC in the eluate of acclimated trickling filters. The biomass was analyzed after the experiment, and it was found to have sorbed about 23 mg LAS/g of dry biomass; this represented about 3% of the LAS applied to the filter. The LAS and the eluates from the trickling filter were further analyzed by HPLC and UV and IR spectrometry. The residual carbon from acclimated filters contained no LAS-like material (HPLC), which was obviously subject to quantitative biotransformation. The residual material comprised > 50 polar metabolites, some of whose UV spectra differed from that of LAS, and most or all of which were sulfonated. These nondegraded metabolites included carboxylated dialkyltetralinesulfonates and sulfophenylcarboxylates. These residual materials showed no detectable toxicity to algae or Daphnia, and did not significantly lower the surface tension of water.
34 citations
TL;DR: In this article, the authors studied the accumulation of nitrite during nitrification in recirculating fish culture systems and found that high nitrite concentrations in the system can entirely be explained by diffusional transport mechanisms in combination with the characteristics of the biofilm.
27 citations
TL;DR: It appears that for a certain inlet ammonia concentration, the hydraulic biofilm loading rate is a key variable influencing the overall biofilter nitrification performance, within a wide range of filter dimensions.
25 citations
TL;DR: The values of the biodegradation coefficient, K b, were found to be reproducible and affected by a combination of high hydraulic loading rate and effluent recycle, which tended to increase the proportion of influent VOCs found in the effluent.
18 citations
TL;DR: It is concluded that the algae, although being absorbed, stay alive on the film and do not contribute significantly to the carbonaceous load on the trickling filter, which appears to be in line with laboratory findings by others who, when they artificially immobilised certain species of algae and passed water over them, concluded that they retained the potential to remove certain compounds from the water.
18 citations
TL;DR: In this paper, a graphical method for the design of nitrifying trickling filters for potable water treatment is presented, which allows the selection of the key design parameters (support media and filter dimensions) based on appropriate design curves.
Patent•
10 Jul 1995
TL;DR: In this paper, an activated sludge treatment process and apparatus are provided for denitrification of a trickling filter plant effluent in which the nitrate nitrogen to BOD5 ratio can be maintained at less than or equal to 0.18 without the use of a nitrate monitor to control supplemental dosing with carbonaceous organic compounds or their salts.
Abstract: An activated sludge treatment process and apparatus are provided for denitrification of a trickling filter plant effluent in which the nitrate nitrogen to BOD5 ratio can be maintained at less than or equal to 0.18 without the use of a nitrate monitor to control supplemental dosing with carbonaceous organic compounds or their salts. The apparatus is equipped with a turbidity meter, a phosphate monitor, and with a substrate storage tank for the addition of carbonaceous organic substrate. The substrate is added immediately at the end of the oxic phase and is continued until phosphate release is detected. Accordingly, the phosphate monitor functions as an indicator of nitrate respiration in the anoxic phase.
TL;DR: In this article, a large pilot scale trickling filter with an established nitrifying biofilm on a cross flow plastic material having a high specific surface area has been used to evaluate the short term effects of changes in hydraulic load and influent ammonium concentration.
Patent•
22 Feb 1995
TL;DR: In this article, a method for removing volatile pollutions from gas streams, comprising the treatment of said gas streams utilizing a combination of a biofilter and a trickling filter, was proposed.
Abstract: The invention relates to a method for removing volatile pollutions from gas streams, comprising the treatment of said gas streams utilizing a combination of a biofilter and a trickling filter, the trickling filter being based on a support material having provided thereon one or more microorganisms of the genus Hyphomicrobium which are suitable for degrading organic sulfur compounds.
01 Jan 1995
TL;DR: In this article, an assessment of municipal wastewater in trickling filters was performed using operating data from wastewater treatment facilities currently in operation, and the evaluated plants were generally meeting their permit requirements, including ammonia-nitrogen limits when applied.
Abstract: An assessment of nitrification of municipal wastewater in trickling filters was performed using operating data from wastewater treatment facilities currently in operation. A survey of trickling filter use in the United States found twenty-seven plants accomplishing some degree of nitrification. Of the twenty-seven plants ten were identified as having operating data sufficient for further analysis. Although most of the plants evaluated were not designed as single-stage systems they all provided sufficient data to evaluate trickling filter performance as a single-stage system. The evaluated plants were generally meeting their permit requirements, including ammonia-nitrogen limits when applied. Analysis of the data compared favorably with the BOD 5 loading rates suggested by the EPA Process Design Manual for Nitrogen Control.
TL;DR: In this article, the authors present the final results of a two-year research programme, which has been funded by the Commission of European Union (STEP) program, which was the main objective was the study of sewage treatment for a wide range of ambient temperatures, in order to produce effluents of adequate quality to meet EU standards.
Journal Article•
01 Jan 1995
TL;DR: The authors' results showed the predominance of genera from the Enterobacteriaceae family, and the cell count was 99% reduced depending on the support material and on the hydraulic charge values, in domestic sewage treated by trickling filters.
Abstract: Domestic sewage was treated by trickling filters with different support materials (polyethylene, polystyrene, rock and polyvinyl chloride) at two hydraulic charges and three different initial concentrations of organic matter. The composition of aerobic and facultative bacterial communities, and the effect of the shock loadings in these microbial populations was determined All bacterial groups were identified before and after the biological treatments. Our results showed the predominance of genera from the Enterobacteriaceae family. During treatments the cell count was 99% reduced depending on the support material and on the hydraulic charge values. The main genera and species identified were: Escherichia coli, Klebsiella sp., Serratia sp. and Proteus sp. and these were removed during the biological treatments.
Patent•
06 Oct 1995
TL;DR: In this article, the amount of treated water to the outlet can be regulated by a regulation device and the distance between the fixation plate XI and the regulation plate VII, where the treated water is pumped through the pump discharge pipe VI against the plate with regulating plate VII and water jets are formed which are disperged over the total surface of the filter material II.
Abstract: The waste water enters through the inlet piping IN to the trickling filter and passes by gravity through the filtermaterial II and the supporting drain floor III to the bottom of the prefabricated tank I. When the waterlevel below the supporting drain floor III in the prefabricated tank I reachs the maximum water level then the level switch of the pump V starts the pump. At that moment the treated water is pumped through the pump discharge pipe VI against the plate with regulating plate VII. Due to the water velocity of the water stream against this plate VII water jets are forms which are disperged over the total surface of the filter material II. A certain amount of the pumped water is due to the pressure losses evacuated through the T-piece in the discharge pipe VI to the outlet OUT. The amount of treated water to the outlet OUT can be regulated by a regulation device and the distance between the fixation plate XI and the regulation plate VII. If the capacity at the inlet IN of the waste water is smaller than the capacity to the outlet OUT, the water level below the supporting drain floor III drops. The pump V stops at the minimum water level. The necessary air for the aerobe function of the trickling filter is assured by the air inlet pipe VIII ( with optional fan IX ) that just ends below the supporting drain floor.The tank has a airtight access X.
TL;DR: In this article, the removal of phosphorus from secondary trickling filter effluents by precipitation with fly ash was studied in comparison with the conventional coagulant, lime, and the optimum dosage of fly ash, as determined by jar test experiments, was 2500-4000 mg/I as compared to only 100 mg/1 for lime to reduce soluble phosphorus of up to 59mg/1 to less than 10 mg /I as P.
Abstract: The removal of phosphorus from secondary trickling filter effluents by precipitation with fly ash was studied in comparison with the conventional coagulant, lime The optimum dosage of fly ash, as determined by jar test experiments, was 2500-4000 mg/I as compared to only 100 mg/1 for lime to reduce soluble phosphorus of up to 59 mg/1 to less than 10 mg/I as P For fly ash, prolonged rapid mix time improved the quality of the treated effluent to an appreciable extent The pH and dissolved oxygen of secondary effluent appeared to have a significant effect on solution phosphate reduction with higher removals for high values of pH and dissolved oxygen concentration