Showing papers on "Trickling filter published in 2004"
01 Jan 2004
TL;DR: In this paper, the application of upflow anaerobic sludge bed (UASB) reactors for the treatment of low-strength domestic sewage was studied for the city of Salta, in northwestern Argentina.
Abstract: In this thesis, the application of upflow anaerobic sludge bed (UASB) reactors for the treatment of low-strength domestic sewage was studied for the city of Salta , in northwestern Argentina . The climate in this region can be defined as subtropical with a dry season. Mean ambient temperature in the city is 16.5oC. Mean sewage temperature during the experiments was 23.0°C (monthly minimum: 17.2°C; daily minimum: 12.6°C). A literature review on the use of upflow reactors for sewage treatment was performed, and a brief description of laboratory, pilot-scale, and full-scale applications from all over the world is presented. Experiments were performed in two pilot plants especially built for this thesis. The first pilot plant was a UASB reactor installed after a conventional full-scale sedimentation tank (settler). The second pilot plant was a two-stage UASB system with posttreatment in five waste stabilization ponds (WSP) in series. In the first pilot plant, chemical oxygen demand (COD) removal efficiencies up to 84% in total COD and 92% in suspended COD were achieved at a mean hydraulic retention time (HRT) of 2 h in the settler and 5.6 h in the reactor, equivalent to an upflow velocity (V up ) of 0.71 m/h. A granular sludge developed in the UASB reactor probably due to the low concentration of suspended solids (SS) and COD in the influent and an adequate combination of HRT and V up . Some of the granules were surprisingly big (up to 5 cm in diameter). The system studied was highly robust and efficient, it consistently delivered a final effluent in compliance with discharge standards for COD and SS, and produced a small amount of well-stabilized sludge. In the two-step UASB system of the second pilot plant, COD removal efficiencies up to 89% were obtained at mean HRTs of 6.4 + 5.6 h (V up = 0.62 + 0.70 m/h), with 83 and 36% removal in the first and second steps, respectively. The effluent concentration was similar to that obtained in the first pilot plant. The performance of the two-step system was not affected during the coldest period of the year, which usually lasts about three months. The anaerobic sludge showed good stability, especially in summer time, and could be directly disposed of without further treatment. After the posttreatment, the effluent also complied with discharge standards for pathogenic microorganisms. It was concluded that a single-stage UASB reactor followed by a series of WSP could be a very efficient, reliable, compact, and simple system for the treatment of raw sewage in subtropical regions like Salta . Finally, a comparative assessment of the sustainability of three technological options for sewage treatment was performed, in terms of a series of technical, environmental, social, and economic criteria and indicators. In this preliminary assessment it was found that, under local conditions, a system UASB + WSP was more sustainable than (a) an aerobic high-rate treatment system based on trickling filters, and (b) a system of conventional WSP. The assessment method used (a multi-criteria weighted-scale matrix) was simple to perform and sensitive enough to detect differences in sustainability between the options compared. A representative panel of local stakeholders must perform the actual assessment in a transparent and participatory way before any concrete policy decision is taken. The final plead of this thesis is that sustainable development will only be achieved through a fully democratic way of decision-making that can go beyond political and economic motivations and that may be able to solve environmental problems and social injustices.
85 citations
TL;DR: The ability to treat groundwater contaminated with low concentrations of ethers in attached growth reactors is demonstrated, with the model somewhat over predicted 1,4-dioxane removal.
Abstract: The ability of a laboratory-scale trickling filter to biodegrade cyclic ethers was investigated and a simple kinetic model was developed to predict ether biodegradation. The trickling filter received a feed solution designed to mimic ether concentrations typically encountered in contaminated groundwater. The reactor was operated for approximately 1 year and was capable of biodegrading 93.97% of 1,4-dioxane at various loading rates in the obligate presence of tetrahydrofuran (THF) as the growth substrate. A simple tanks-in-series hydraulic model combined with a kinetic model that incorporated cometabolism was utilized to simulate removal of THF and 1,4-dioxane. Model simulations of THF removal were satisfactory for all loading rates analyzed. However, the model somewhat over predicted 1,4-dioxane removal. This research demonstrates the ability to treat groundwater contaminated with low concentrations of ethers in attached growth reactors.
40 citations
TL;DR: The original data used for the nitrification model derivations have been reanalysed, to investigate the degree of nitrogen removal across the trickling filter process and suggest that a significant degree of nitrification occurred in areas of high heterotroph activity (BOD removal).
21 citations
TL;DR: The most common semi-intensive configuration used in Israel is made of anaerobic ponds followed by aerated lagoons, which remove about 75-80% of the BOD and are followed by wastewater reservoirs for storage and complementary treatment.
20 citations
TL;DR: The kinetic mechanisms of purifying waste gas containing toluene in low concentrations were investigated by using a biological trickling filter packed with biofilm packing-material and an ‘Adsorption-Biofilm Theory’ and associated kinetic model were established.
19 citations
TL;DR: In this paper, the authors conducted an experiment whereby flows to the TFs and NTFs were varied to test ammonia removal capabilities of the facility and found that TFs removed an average of 2.4×10-4kgN/(DM2) and NFTs removed 1.5×10 -5 kgN/(dm2) due to low loading.
Abstract: The trickling filter solids contact water pollution control facility for the city of Ames, Iowa has successfully nitrified wastewater with trickling filters for the past decade. Both first stage, carbonaceous biochemical oxygen demand removing trickling filters (TFs) and second stage, nitrifying TFs (NTFs) remove significant quantities of ammonia from the wastewater. Based on operating data from January 1999 through December 2001, the average specific ammonia removal rate for the TFs was 1.5×10-4kgN/(dm2). Most probable number testing confirmed the presence of nitrifiers in the top media layer of both stages of trickling filters. An experiment was performed whereby flows to the TFs and NTFs were varied to test ammonia removal capabilities of the facility. During the experiment, the TFs removed an average of 2.4×10-4kgN/(dm2) and the NTFs removed an average of 1.5×10-5kgN/(dm2) due to low loading. Data collected during the study varied with operating conditions. It was compared to and used to calibrate NTF...
15 citations
TL;DR: In this article, a long-term experimental program was conducted using a TF/SC pilot plant constructed at the Marrero, La., wastewater treatment plant, and the experimental data confirmed that flocculation of the particulate COD contained in the trickling filter effluent explains the high total COD removal observed at the SCC.
Abstract: The trickling filter/solids contact ~TF/SC! process was developed in the late 1970s to improve the quality of the final effluent from existing trickling filter plants, to be able to meet stricter Environmental Protection Agency effluent requirements. Although this process has successfully achieved this objective, it is still not completely understood, there is limited information regarding the floccu- lation phenomena occurring in the solids contact chamber ~SCC!, and no information could be found on the relationship between flocculation and organic matter removal kinetics. To better understand the kinetics of biological flocculation in a continuous flow SCC, a long-term experimental program was conducted using a TF/SC pilot plant constructed at the Marrero, La., wastewater treatment plant. This program started in January 1998 and has continued through date. The present article will focus on two major areas: ~1! the kinetics of bioflocculation in the SCC; and ~2! effect of bioflocculation on chemical oxygen demand ~COD! removal. Analysis of the wastewater composition revealed that, on the average, only 18.7% of the total COD in the SCC influent is truly dissolved. Therefore, most of the total COD removal observed in the SCC must be due to a physical process, such as flocculation. The experimental data confirmed that flocculation of the particulate COD contained in the trickling filter effluent explains the high total COD removal observed at the SCC. Both total and colloidal COD removals are well explained by the first-order flocculation model.
14 citations
TL;DR: It is suggested that substantial nitrification of pig lagoon wastewater can be attained particularly using aerobic treatments with enriched nitrifying populations, and that large mass removal of N from pig wastewater may be possible by sequencing nitrification and denitrification unit processes.
Abstract: Nitrification is a necessary and often limiting process in animal waste treatment for removal of nitrogen as N2 through biological nitrification/denitrification systems. We evaluated three technologies for enhancing nitrification of pig lagoon wastewater prior to denitrification: overland flow, trickling filter, and a bioreactor using nitrifying pellets. The overland flow system consisted of a 4 × 20‐m plot with 2% slope with a subsurface impermeable barrier receiving a total N loading rate of 64–99 kg N ha−1 day−1. Total N removal efficiency ranged from 36 to 42%, and 7% of the total N application was recovered in the effluent as nitrate. The trickling filter consisted of a 1‐m3 tank filled with marl gravel media which supported a nitrifying biofilm. Lagoon wastewater was applied as a fine spray on the surface at hydraulic loading rates of 684 litres m−3 day−1 and total N loading rates of 249 g m−3 day−1. The media filter treatment transformed up to 57% of the inflow total N into nitrate when wa...
14 citations
TL;DR: It was found that BDOC fraction was independent of the initial DOC concentration and was dependent on the source of wastewater and/or the types of wastewater treatment, while the amount of BDOC in the wastewater depended not on the concentration of DOC, but on the effectiveness of pretreatment.
Abstract: Biodegradable dissolved organic carbon (BDOC) analyses and abiotic adsorption of dissolved organic carbon (DOC) from different wastewater effluent were conducted to evaluate biotic and abiotic removal mechanisms as a function of the initial DOC concentration and source of DOC using soil batch reactors. To obtain high DOC concentrations, a laboratory-scale reverse osmosis unit was used. It was found that BDOC fraction was independent of the initial DOC concentration and was dependent on the source of wastewater and/or the types of wastewater treatment. The BDOC fractions varied from 9 to 73%. Trickling filter effluent (Tucson, Arizona) showed the highest BDOC, ranging from 65 to 73% biodegradable, while wastewater treated by the soil aquifer treatment (SAT) (NW-4) was found to be most refractory, with DOC removals of 9 to 14%. For nitrified/denitrified tertiary effluent (Mesa, Arizona) and secondary effluent (Scottsdale, Arizona), 36 to 42% removal of DOC was observed during the BDOC test. The amount of BDOC in the wastewater depended not on the concentration of DOC, but on the effectiveness of pretreatment. Abiotic adsorption capacity of wastewater effluent varied from 6 to 18%. Molecular weight distribution analyses showed that more than 50% of DOC in the Scottsdale concentrate had a molecular weight of less than 1000 Da, and no significant change in distribution profiles occurred after approximately 12% abiotic adsorption with both soils with acclimated microorganisms (SAT soil) and soils without acclimated microorganisms (non-SAT soils). Hence, preferential adsorption was not observed and the presence of acclimated microbes did not influence adsorption.
13 citations
TL;DR: Secondary settling dynamics at maximal capacity were investigated at a full scale wastewater treatment plant which utilizes a unique process solution incorporating pre-denitrification with post-nitrification in nitrifying trickling filters.
12 citations
Patent•
03 Feb 2004
TL;DR: In this paper, real-time monitoring of biomass accumulation within synthetic or plastic modular media is provided, which relates to operation of a trickling filter (200) used in wastewater treatment.
Abstract: The invention relates to operation of a trickling filter (200) used in wastewater treatment. Real-time monitoring of biomass accumulation within synthetic or plastic modular media (204) is provided.
TL;DR: The main results have been: a quick start-up of the biological reactors obtainable thanks to a pre-colonization before the transportation of the plastic carriers to the refuge at the beginning of the tourist season, and significantly higher removal efficiency compared to other fixed biomass systems, such as trickling filters, but the energy consumption is higher.
01 Jan 2004
TL;DR: In this article, a Radial Jet Nozzle (RJN) configuration instead of conventional circular nozzle was used to increase the percentage of dissolved oxygen (DO%) from the saturation value by 15% than conventional nozzle for the same power consumption.
Abstract: Oxygen Transfer Rate (OTR) is considered one of the most important factors that affect trickling filter performance, insufficient OTR limits trickling filter performance and generate malodor, another factor that affects trickling filter performance is the percent wetting of the media surface. Effective distribution system may achieve increase in OTR and maintain maximum wetting of the media surface. The present study is an attempt to enhance distribution system efficiency, so the trickling filter performance by using Radial Jet Nozzle (RJN) configuration instead of conventional circular nozzle. The distributoroffset distance from the bed is taken into consideration as a geometric variable parameter. Results show that RJN configuration increased the percentage of dissolved oxygen (DO%) from the saturation value by 15% than conventional nozzle for the same power consumption in two cases. Results also indicated that increase offset ratio will increase the DO% by 5 & 7 % for RJN and conventional nozzle configurations respectively. The study also evaluated the effect of inner pipe diameter and fluid outlet velocity on DO%.
Patent•
09 Jun 2004
TL;DR: In this paper, a trickling filter for biological treatment of waste water or sewage is described, and it is characterized by that the upper portion of said trickling filtering is equipped with seawge inlet line, washing water line, and air discharging line, the lower portion of the equipment was equipped with a horizontal water-collecting plate with drain gully.
Abstract: The present invention relates to a trickling filter for biological treatment of waste water or sewage, and it is characterized by that the upper portion of said trickling filter is equipped with seawge inlet line, washing water line and air discharging line, the lower portion of the equipment is equipped with air inlet line and water outlet line, and the interior of said equipment is equipped with a horizontal water-collecting plate with drain gully, said equipment is divided into upper and lower two portions by said water-collecting plate, the upper portion of the water-collecting plate is biological filter, and the lower portion is contact oxidation tank in which the ceramic soft filler is held. Said invention can implement second-level biological treatment of sewage, do not discharge excess sludge and waste gas and can reduce secondary pollution.
01 Jan 2004
TL;DR: In this paper, the authors developed a biological process for the removal of nitrogenous compounds from metal processing wastewater using an aerobic continuously stirred tank reactor (CSTR) followed by an anaerobic packed column and was run using real wastewater from a metal processing operation.
Abstract: Although several nitrification / denitrification processes are established for the removal of ammonia and nitrate from municipal and industrial wastewaters, there are few reported results on the removal of these ions from metal processing and finishing wastewaters. Sources of ammonia and nitrate in the wastewater include the use of ammonium-nitrate-fuel oil as a blasting agent, and the use of other nitrogen-containing reagents during processing. Unlike municipal wastewater, there is very little organic content in metal processing wastewaters. The objective of this work was to develop a biological process for the removal of nitrogenous compounds from metal processing wastewater. The system comprised an aerobic continuously stirred tank reactor (CSTR) followed by an anaerobic packed column and was run using real wastewater from a metal processing operation. The system was inoculated using humus sludge from a municipal trickling filter and a period of approximately 4 weeks was required for a denitrifying biofilm to develop. Results showed that ammonia removal occurred readily in the CSTR while nitrite oxidation was slower to develop. The CSTR was found to be suitable for ammonia oxidation. The gravel-packed column reactor was found to be unsuitable for the removal of nitrate in the configuration used. An effluent that is low in nitrogen can be obtained with this system with additional carbon introduced after the CSTR. The critical parameters for denitrification are nitrate concentration, temperature, influent flow rate and mean cell retention time. By employing an integrated process comprising nitrification and denitrification, high nitrogen removal efficiencies can be obtained.
Journal Article•
TL;DR: In this paper, a review of the literature was undertaken to determine the ranges of pathogen removal by the unit processes commonly used in the treatment of wastewater prior to disinfection, and it was found that the order of effectiveness ranged from primary sedimentation, followed by trickling filter, physicochemical treatment with alum/polymer, rapid sand filtration, activated sludge.
Abstract: A review of the literature was undertaken to determine the ranges of pathogen removal by the unit processes commonly used in the treatment of wastewater prior to disinfection. It was found that the order of effectiveness ranged from primary sedimentation, followed by trickling filter, physicochemical treatment with alum/polymer, rapid sand filtration, activated sludge, physicochemical treatment with lime, dissolved air flotation, slow sand filtration, lagoons (with sufficient HRT) and membrane processes.
Patent•
24 Sep 2004
TL;DR: In this article, a method for purifying gaseous media is presented, which is characterized by a short run-in time and a high decomposition rate, where the medium is brought in contact with water and microorganisms which are selected in accordance with impurities of the medium and are applied to the trickling filters.
Abstract: The invention relates to a device for purifying gaseous media, comprising a container (1) that is provided with at least one filtering chamber (2) which is disposed therein, is filled with and humidified by means of trickling filters (14), and is penetrated by the medium that is to be purified. Also disclosed is a method for purifying gas in such a device. The aim of the invention is to create a device and a corresponding method which are characterized by a short run-in time and a high decomposition rate. Said aim is achieved by a device that is characterized in that the trickling filters (14) are impinged upon by microorganisms (13) which are selected in accordance with the impurities of the medium and by a method that is characterized in that the gaseous medium is brought in contact with water and microorganisms (13) which are selected in accordance with the impurities of the medium and are applied to the trickling filters (14).
01 Jan 2004
01 Jan 2004
TL;DR: In this paper, a literature survey and mathematical modelling of three different trickling filter configurations was performed to determine the best system for denitrification in fixed film domestic wastewater treatment systems without an external carbon source.
Abstract: Fixed film biological systems have been used for the treatment of wastewater for many years. These systems have been extensively and generally effectively used for the removal of carbon from wastewater sources. In recent years the legislative demands for nutrient removal, both in Australia and overseas, has seen a move away for biological fixed film systems to activated sludge (suspended growth) systems because of the perceived inability of fixed film systems to provide appropriate nutrient removal. However extensive research has been conducted into this field. The most common approach to biological denitrification in fixed film treatment systems has been to place an anoxic zone either before (pre-anoxic) or after (post-anoxic) the aeration system (i.e. Trickling Filter, Rotating Biological Contactor, etc.). However this previous research has focused on the use of an external carbon source in the post anoxic zones to provide the carbon requirements for the biological denitrification reaction. This project was aimed at determining the nitrogen removal potential of fixed film biological treatment systems without the need for an additional carbon source. Following a literature survey and mathematical modelling of three different trickling filter – anoxic vessel configurations, the pre-anoxic system was determined as the best system for denitrification in fixed film domestic wastewater treatment systems without an additional carbon source. It is however recommended that the models created in this project be applied to an experimental system to determine their accuracy. This experimental verification of the modelling performed is expected to be undertaken in the second half of this year.