Showing papers on "Trickling filter published in 1992"

Regulating factors of denitrification in trickling filter biofilms as measured with the oxygen/nitrous oxide microsensor

Abstract: Microzonation of denitrification in trickling filter biofilms was studied using a combined microsensor for O2 and N2O. Denitrification was measured as a function of concentrations of O2, NO3−, organic matter and NH4+ and was found to occur only in part of the biofilm. At increased concentrations of NO3− the thickness of the denitrifying zone increased and thereby increased the total denitrification whereas addition of dissolved organic matter increased the rates of denitrification within the denitrifying part of the biofilm, expressed per volume biofilm. The presence of NH4+ decreased the rate of NO3− assimilation and thereby increased the availability of NO3− for denitrification. Denitrification was only found at O2 concentrations below approximately 20 μM. The toxic zone normally extended 0.2–0.3 mm below the biofilm surface, but when the biofilm was exposed to light photosynthetically produced O2 pushed the oxic-anoxic interface down to 1.3 mm. Denitrification stopped when O2 was introduced to the denitrifying zone, but even after exposure to O2 for 18 h denitrification began immediately after returning to anoxic conditions. Steady state in denitrification was then reached in only 30 min and the rate found then was identical to the rate before exposure to O2, as well as the rate 15 h after return to anoxia. The immediate onset of denitrification suggest that most of the denitrifiers in the biofilm possessed constitutive enzyme systems for denitrification.

The removal of dichloromethane from waste gases in a biological trickling filter

Abstract: • A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers.

Process for the biological purification of waste air streams

Abstract: In a process for the biological elimination of halogen- and sulfur-containing gaseous pollutants from a waste air stream, the waste air stream is passed through an intermittently moistened trickling filter tower. In a preferred variant of the process, individual sections of the surface of the trickling filter are subjected to intermittent phase-displaced moistening. Cyclic moistening of the trickling filter sections can be achieved in this way. The volume-time yield in the biological purification of gas streams can be considerably improved by this process.

Process for liquid manure disposal

Abstract: The process is characterised in that the urea in the liquid manure is enzymatically hydrolysed, a mechanical preclarification, if required, is carried out before or after the hydrolysis, the suspended and colloidally dissolved constituents in the liquid manure are, if required, flocculated and/or precipitated using inorganic or organic electrolytes or polyelectrolytes or mixtures thereof, the flocculated or precipitated colloids and solids from the liquid manure, if required, are separated off by flotation with subsequent mechanical separation of the flotate, the ammonia dissolved in the liquid manure is removed therefrom by degassing, a residual liquid manure being obtained, a further mechanical clarification of the residual liquid manure is carried if required, a neutralisation of the residual liquid manure is carried out if required and the residual liquid manure which is obtained from stage 5, 6 or 7 is applied to a trickling filter or is disposed of separately by aerobic bacteria or is fed to the denitrification stage of a sewage treatment plant or is divided by electrodialysis into a concentrate and a diluate, the concentrate being fed to the denitrification stage of a sewage treatment plant.

Biological fixed-film systems

Abstract: This paper includes reports on several biological fixed film systems in wastewater and hazardous waste treatment. Biological treatment of a refinery wastewater was studied in a rotating biological contactor (RBC) unit coupled with polyurethane foam (PUF) as a porous biomass support attached on both sides of the biodisks. The RBC-PUF bioreactor exhibited better performance than conventional RBCs for the removal of chemical oxygen demand (COD), NH{sub 3}-N, phenol, hydrocarbons, and suspended solids because of higher concentrations of active biomass. Successful performance of an anaerobic-aerobic treatment process using a combination of RCBs with activated sludge was achieved for treating a dye wastewater. Two high-rate trickling filters, cross-flow (CF) and vertical flow, were examined over a two year period for biological treatment of seafood processing wastewater. Results suggested superior performance of CF plastic media with substrate removal following a pseudo half-order kinetic reaction. Submerged structured packings in biofilm reactors were tested and characterized for a wide range of applications. Their efficiency was discussed in terms of contaminant removals and SS retention.

A method and apparatus for treating a fluid

Abstract: Apparatus 1 for treating a fluid, in this case wastewater, comprising a vessel or tank 2, means 3 to supply the wastewater in an alternating sequence to the vessel 2, anda means 4 for oxygenating the bed of granular media 5 to provide aerated filter media. The filter bed is aerated during operation by air, oxygen enriched air or other gas being introduced at or adjacent the base (as viewed) of the bed through the means 4, which may be a perforated manifold, diffuser or the like extending substantially over the whole surface area of the bed 5. Also the bed 5 is a granular media such as natural minerals or blast furnace slag media to the surface of the discrete particles of which is attached bacteria and micro-organisms (a biomass) which effects treatment of the fluid. The influent at 3 derived from sewage is counter current to the air, and is particularly a non-nitrified influent namely wastewater that has previously been treated to reduce the BOD (biological oxygen demand) and suspended solids concentrations. The blast furnace slag media 5 has an average particle diameter of 2.8-4.0mm and a porosity of 13.9%. In carrying out the process the periodic reversal of the flow through the filter bed maintain the concentration gradient of the micro-organisms (biomass) substantially uniform as a desired concentration of micro-organisms throughout the depth of the bed under all operating conditions in the embodiments illustrated. This provides for a uniform, efficient treatment of the sewage.

Biotechnological Removal of Ethene from Waste Gases

Abstract: Publisher Summary This chapter presents preliminary results regarding ethene removal from waste gases with a conventional trickling filter. It also discusses the possibility of adding an organic solvent as an ethene vector to increase the sorption of ethene. Biological waste-gas treatment can be an alternative for physico-chemical treatment, but the use of biological systems may become critical, as the organic compound becomes less water soluble. Experiments are carried out in a continuously operated lab-scale trickling filter. The trickling filter consists of a rectangular shaped plexi-glass column. The preliminary results show that the biomass growth on the packing material could be enhanced by loading the trickling filter with a secondary ordinary carbon source through the liquid circuit. The use of a solvent to increase the sorption of ethene is probably not possible, because ethene shows a low solubility in organic solvents. In addition, the use of a solvent to increase the sorption of ethene is probably not possible, because ethene shows also a low solubility in organic solvents.

Biological trickling filter type water purifying device

Abstract: PURPOSE:To improve the instability of an activated sludge type treatment system and to enable treatment within short time by constituting this device with the combination of an agitation tank providing a diffusing pipe and an injecting device of biological decomposing agent and the reaction tank providing an nonwoven fabric and the diffusing pipe respectively. CONSTITUTION:In the reaction tank 3, treating water executes the biological decomposition treatment at the surface of plural filtering layers 8 by an aerobic microorganism, and at the central part of the filtering material anaerobic microorganism are living like a sandwich and anaerobic decomposition treatment proceeds and an emulsified oil component is selectively decomposed by an enzyme. The bio-membrane stuck to the surface of the filtering material is cleaned and floated by the pealing off phenomenon of the activated sludge and a floating bio-membrane is made flow into a sedimentation basin. Into the downstream of the reaction tank 3, the sedimentation basin 4 is justaposed, and the reaction product formed by biological decomposition in the reactor 3 and the floating bio-membrane from the filter surface formed by pealing off phenomenon of the activated sludge of the surface of filtering member are together made flow into the sedimentation basin 4. The sludge settled in the sedimentation basin is returned into the stirring tank 2 by the pump 11 and the floating product is sent back into the precipitating and separation tank 1.

Motion controller for wastewater treatment trickling filter

Abstract: An apparatus for controlling the rate of rotation of a wastewater distribution assembly for a sewage treatment trickling filter contained by a vessel. The wastewater distribution assembly is of the type including a support and at least one distribution arm having an end terminating adjacent a wall of the vessel. The apparatus comprises a carriage having at least one wheel rotatably mounted to the end of the distribution arm and adapted to engage the vessel and means mounted to the carriage for controlling the rotation rate or free-wheeling of the wheel.

Biological waste water purification plant

Abstract: A biological waste water purification plant has at least one trickling filter 4 provided between an upper waste water distributor 14 and a lower collecting trough 15, which trickling filter has a water-permeable filter layer 5, 6 which takes up microorganisms. In order to be able to ensure reliable oxygen supply to these microorganisms, a baffle layer 7, which alternately blocks or releases the water throughflow, is arranged downstream of the filter layer 5, 6.

Process efficiency characterization of plastic medium trickling filter

Abstract: A laboratory scale pilot plant investigation was carried out to study the performance of a plastic medium trickling filter and to compare the treatment efficiency of this trickling filter with stone medium filter. Treatment efficiencies were studied at different hydraulic and organic loading rates. The result of this investigation indicates that the plastic medium trickling filters were more efficient than stone medium filters at the loadings in excess of 0.52 ∗ 10−6 kg BOD cubic meter per second. However, at low hydraulic and organic loadings stone media filter gave better performance than plastic filter.

A Novel Bioreactor for the Biodegradation of Toxic Aromatic Solvents

Abstract: As one of the main industrial pollutants, aromatic solvents such as benzene, toluene, and xylenes (collectively known as BTX) have been causing the detrimental effects on environment 1-5]. Much effort has been made on the elimination of these compounds from a waste stream, and various methods have been reported [3-5]. In biological treatment system, three types of processes have been developed: bioscrubber, trickling filter, and biofilter[3,5]. Because of low solubility in water and high volatility, BTX are usually fed into the degradation process in gas phase with air stream [3]. In conventional processes, however, volumetric degradation rate was relatively low, less than 0.04 g/L/h, and efficient control of operational conditions such as moisture content in the bed and transfer rate of compounds to be treated was reported to be difficult to realize [3].