Showing papers on "Trickling filter published in 2008"

Behavior of Steroid Hormones and Conjugates During Wastewater Treatment – A Comparison of Three Sewage Treatment Plants

Abstract: The fate of the steroid hormones 17 β-estradiol, estrone, estriol, 16 α-hydroxyestrone, and β-estradiol 17-acetate, the hormone-conjugates β-estradiol 3-sulfate and estrone 3-sulfate, and the oral contraceptives 17 α-ethinylestradiol and mestranol were studied during wastewater treatment as wastewater treatment plants are the major source contamination of urban surface waters with steroid hormones. The elimination efficiencies of three different concepts of WWTPs, i. e., activated sludge versus trickling filter, were compared over four weeks at different weather conditions. While larger WWTPs operating on activated sludge eliminated hormones more constantly than smaller WWTPs, heavy rainfall events led to a collapse of the elimination efficiency. By using trickling filter techniques for the treatment of wastewater an elimination of the steroid hormones could not be observed. Additionally, mass flows on a per person basis are compared. In the three experiments, which ran continuously for four weeks each, it turned out that the concentrations of ethinylestradiol and mestranol were below 6 ng/L in all samples. The inflow concentrations were 70 to 82 ng/L (estrone), 17 to 44 ng/L (estradiol), 61 to 130 ng/L (hydroxyestrone), 189 to 255 ng/L (estriol), 10 to 17 ng/L (estrone-3-sulfate) and about 28 ng/L (estradiol-3- sulfate). While in the activated sludge treatment plants the elimination of estrone was 90 and 50%, respectively, estrone was formed from precursors in the trickling filter plant. A similar situation occurred for 17β-estradiol, estrone 3-sulfate, and estradiol 3-sulfate. Hydroxyestrone was eliminated with similar efficiencies in all wastewater treatment plants (64 to 82%), as well as estriol (34 to 69%). Accordingly, the emissions of the wastewater treatment plants differed largely and were not attributed to the size of the respective plant, only.

Use of shredded tire chips and tire crumbs as packing media in trickling filter systems for landfill leachate treatment.

Abstract: Scrap tire stockpiles are breeding grounds for pests, mosquitoes and west Nile viruses and, thereby, become a potential health risk. This experimental study was carried out in six stages to determine the suitability of shredded tire materials in a trickling filter system to treat landfill leachate. Biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and NH3‐N removals were obtained in the range of 81 to 96%, 76 to 90% and 15 to 68%, respectively. The removal of organics appears to be largely related to total dissolved solids reduction in leachate. A sudden increase, from time to time, in organic content of effluent could be attributed to biomass sloughing and clogging in the trickling filters. However, tire crumbs exhibited more consistent organics removal throughout the experimental program. Due to the high surface area of shredded tire chips and crumbs, a layer of biomass, 1–2 mm thick, was attached to them and was sloughed off at an interval of 21 days. Apart from that, as shredded ...

Biological Cr(VI) reduction in a trickling filter under continuous operation with recirculation

Abstract: BACKGROUND: Hexavalent chromium (Cr(VI)) is toxic to humans, animals and plants. Conventional treatment technologies reduce Cr(VI) to the less toxic and mobile Cr(III), but these methods are usually expensive and generate secondary waste. Microbial Cr(VI) reduction has recently gained attention as a detoxification process, since it enables Cr(VI) reduction through relatively cheap and simple methods. The aim of this work was to investigate the mechanism and the performance of biological Cr(VI) reduction using mixed cultures originated from industrial sludge under continuous operation with recirculation in a pilot-scale trickling filter. RESULTS: Biological Cr(VI) reduction was studied using a pilot-scale trickling filter filled with plastic media under continuous operation with recirculation and the use of indigenous bacterial population. The effect of the organic carbon (electron donor) concentration was examined for constant Cr(VI) influent concentration at about 5.5 mg L−1 and volumetric flow rates ranging from 60 to 900 mL min−1. The highest reduction rate achieved was 1117 g Cr(VI) m−2 d−1 for a volumetric flow rate of 900 mL min−1. The system's reduction capacity was significantly affected by chromate loadings, resulting in frequent backwashing of the filter. The determination of the reduction mechanism was also studied using batch cultures of free suspended cells and culture supernatant. CONCLUSION: The high reduction rates combined with the low operating cost indicate that the above technology can be a viable solution for the treatment of industrial chromate effluents. Copyright © 2008 Society of Chemical Industry

Biological Cr(VI) reduction in a trickling filter under continuous operation with

Abstract: BACKGROUND: Hexavalent chromium (Cr(VI)) is toxic to humans, animals and plants. Conventional treatment technologies reduce Cr(VI) to the less toxic and mobile Cr(III), but these methods are usually expensive and generate secondary waste. Microbial Cr(VI) reduction has recently gained attention as a detoxification process, since it enables Cr(VI) reduction through relatively cheap and simple methods. The aim of this work was to investigate the mechanism and the performance of biological Cr(VI) reduction using mixed cultures originated from industrial sludge under continuous operation with recirculation in a pilot-scale trickling filter. RESULTS: Biological Cr(VI) reduction was studied using a pilot-scale trickling filter filled with plastic media under continuous operation with recirculation and the use of indigenous bacterial population. The effect of the organic carbon (electron donor) concentration was examined for constant Cr(VI) influent concentration at about 5.5mg L −1 and volumetric flow rates ranging from 60 to 900mL min −1 . The highest reduction rate achieved was 1117g Cr(VI) m −2 d −1 for a volumetric flow rate of 900mL min −1 . The system’s reduction capacity was significantly affected by chromate loadings, resulting in frequent backwashing of the filter. The determination of the reduction mechanism was also studied using batch cultures of free suspended cells and culture supernatant. CONCLUSION: The high reduction rates combined with the low operating cost indicate that the above technology can be a viable solution for the treatment of industrial chromate effluents.  2008 Society of Chemical Industry

Bench-Scale Evaluation of Sonication as a Pretreatment Process for Ultraviolet Disinfection of Wastewater

Abstract: It is generally known that sonication improves ultraviolet (UV) disinfection kinetics of municipal effluents by breaking large suspended particles. However, the feasibility of sonication as a pretreatment technology largely depends on wastewater quality and discharge requirements. The purpose of this study was to investigate the potential benefits of ultrasound for improving the UV disinfectability of various effluent types, including primary, activated sludge, and trickling filter effluents. It was found that the tailing level of the dose-response curve at high UV doses (>40 mJ/cm 2 ) decreased with the increased sonication time. The reduction in the tailing level had a strong correlation with the decrease in the number concentration of large particles (>60 μm) such that 1 log reduction in the number concentration of large particles resulted in 1.4, 1.1, and 1.7 log reductions in the tailing level for primary, activated sludge, and trickling filter effluents, respectively. However, the improvement in the UV disinfectability due to sonication was partly offset by the reduction in the UV transmittance of the effluent.

Hydrogen sulfide scrubber

Abstract: A trickling filter removes hydrogen sulfide from gas, preferably using heated digester effluent for nutrients and neutralization. Biogas produced from an anaerobic digester, and containing H2S, is pumped or sucked through the trickling filter tank, which comprises at least a portion that is packed with media(s) and sealed to prevent unplanned entry of air. In said system, gas flows up through the filter as a preferably heated digester effluent solution trickles down. A further feature of the preferred embodiments may be that digested manure is used to neutralize acidic scrubber by¬ product, for example, by mixing of excess filter tank nutrient flow with digested manure prior to its return to the anaerobic digester outfall. The preferred embodiments may comprise nitrifying the scrubber, as the scrubber may also provide a home for nitrifying bacteria that will convert a portion of the circulating ammonia to nitrate. A preferred cleaning technique comprises filling the filter/tank with water, allowing floatable media to float, and aggressively/rigorously agitating the media, for example, by injecting liquid or gas through nozzles mounted in the tank to loosen bacteria and sulfur.

Simultaneous treatment of graywater and waste gas in a biological trickling filter.

Abstract: Biological processors are typically used in liquid- and gas-phase remediation as separately staged systems. This research presents a novel application of a biotrickling filter operated for simultaneous treatment of contaminants present in graywater and waste gas (ammonia and hydrogen sulfide). Liquid- and gas-phase contaminants were monitored via bioreactor influent/effluent samples over the course of a 300-day study. An oxygen-based bioassay was used to determine spatial location of the functional groups involved in the biodegradation of surfactants, dissolved hydrogen sulfide, and ammonium. Results indicated that a biotrickling filter is able to support the wide range of microbial species required to degrade the compounds found in graywater and waste gas, maintaining conversion efficiencies greater than 90% for parent surfactant compounds and waste gas constituents. These results provide evidence of an operational scheme that potentially reduces footprint size and cost of graywater/waste gas biotreatment.

Combined biological trickling filter of denitrification and dephosphorization

Abstract: The invention relates to a composite biological trickling filter for denitrification and dephosphorization, belonging to the technical field of sewage treatment. The biological trickling filter is cylinder-shaped and comprises a water distributing area, a stuffing layer and a water catch area from top to down; wherein, the water distributing area comprises a plurality of rollers, a rotary water distributor, a water inlet pipe, a water pipe, a water sprayer and tracks; the water inlet pipe is connected with the rotary water distributor, the rotary water distributor is connected with the water pipe which is provided with a water outlet, the water sprayer is positioned below the water pipe and is connected with the rollers; five layers of grid frames are arranged vertically in the stuffing layer, and the grid frames separate the stuffing layer into a grid structure, so that the stuffing layer is successively separated from bottom to top into a stone and sand layer, a composite steel slag stuffing layer, a plaster stuffing layer, a sawdust stuffing layer and a coke layer; the water catch area comprises a header tank, a water outlet pipe and a water catch plate, wherein, the header tank is positioned at the bottom of the trickling filer, and the water outlet pipe is connected with the header tank. By introducing the grid frames, the composite biological trickling filter has the advantages of eliminating the problems of the filter blockage, water accumulation and other defects, effectively improving the aerobic bacteria processing performance of the composite biological trickling filter, efficiently removing COD and simultaneously achieving the effects of denitrification and dephosphorization.

Removal of ammonia from drinking water by biological nitrification in a fixed film reactor

Abstract: The absence of water catchment protection often results in contamination of drinking water supplies. Waters in South East Asia have been exploited to support extensive agriculture, industry, power generation, public water supply, fisheries and recreation use. Ammonia has been identified as a significant contaminant of drinking water because of its ability to affect the disinfection efficiency of chlorine. The interference of ammonia with chlorination is a prevalent and expensive problem faced by many water treatment plants (WTPs) located throughout South East Asia. The conventional approach for ammonia removal was to pre-chlorinate using high concentrations of chlorine, which has a number of disadvantages including the formation of disinfection by-products and high chlorine consumption. This thesis investigated the application of high rate nitrifying trickling filters (NTFs) as a means of ammonia removal from a polluted lowland water source as an alternative to pre-chlorination. NTFs are widely used for the biological remediation of ammonia rich wastewater, however their performance when required to operate under low ammonia concentrations for potable water applications was unknown. A NTF pilot facility consisting of one large-scale, and three small-scale NTFs were constructed at Hope Valley WTP in South Australia. The NTFs were operated to simulate the raw water quality of a polluted catchment identified in Indonesia (Buaran WTP), including variations in ammonia, biological oxygen demand (BOD5), and turbidity. Results confirmed that plastic-packed NTFs were able to operate equally successfully under low ammonia-N concentrations, some 10- to 50-fold lower that that of conventional wastewater applications, where complete conversion of ammonia to nitrate was consistently observed under these markedly reduced loadings. Results also showed that when operated under mass loads equivalent to typical ammonia loading criteria for wastewater NTFs, by increasing hydraulic flow¬, comparable apparent nitrification rates were achieved. These results confirmed that mass transport limitations posed by low ammonia-N concentrations on overall filter performance were insignificant. This thesis also investigated the impact of organic carbon quantity and biodegradability on the nitrification behaviour of the pilot NTF. Results demonstrated that organic carbon loading, rather than the C:N ratio, was an important regulator of filter nitrification capacity, where a linear decline in nitrification performance correlated well with sucrose and methanol augmented carbon loads. Extensive monitoring of inorganic nitrogen species down the NTF, to profile nitrification behaviour, showed sucrose-induced carbon loads greater than 870 mg sBOD5 m–2 d–1 severely suppressed nitrification throughout the entire filter bed. This study also confirmed that critical carbon loads for nitrification varied among carbon sources. In contrast to sucrose, when a more native-like carbon source was dosed (organic fertiliser), no…

A Simple Technology for Industrial Wastewater Treatment

Abstract: The main object ive of this study is evaluation of suggested s econdary industrial wastewater design system, called trickling filter, with different materials (rice straw, luffa, rice straw & luffa, bricks shale fragments and LECA) w hich are environmentally friends, a s a filter bed to reuse the effluent i n irrigation purpose. The experimental work was conducted on two parts; first part was oil water separator (OWS) as a p rimary t reatment step, the second part was the suggested design (trickling filter) as a secondary treatment. The res ults showed high ef ficiency with ri ce st raw & luffa as a f ilter b ed where t he characteristics of final effluent were 28 mg /l, 103 mg/l, 20 mg/l, 0.7 mg /l, 37.88 N TU, 1.59 g /l and 0. 19 s/m for B OD, COD, TSS, Oil and grease, Turbidity, TDS and Conductivity, respectively. Moreover, the removal percents were between 87-97 %. These characteristics of final effluent were suitable for irrigation purposes or f or d ischarging into streams.

Constructed wetland system for sewage treatment

Abstract: An artificial swampy land for treating wastewater is provided to improve a natural purification effect, by discharging sediment and microorganism slurry precipitated in the wastewater so as to prevent a culture layer from being blocked. A concrete structure(10) has a wastewater inlet(10a) and a treatment water outlet(10b). Draining partition walls(31,33,35,37) are arranged at a uniform interval within the concrete structure. The wastewater inputted through the wastewater inlet is stored in concrete structure. Freshwater partition walls(40,41,43,45,47) are respectively disposed between the draining partition walls. The freshwater partition walls have lower heights than the draining partition walls. A first culture soil layer(21) is formed within the concrete structure. Marshy plants for naturally purifying the wastewater are planted in the first culture soil layer. A precipitating bath(11) precipitates suspended solids contained in the wastewater. The wastewater discharged from the precipitating bath is inputted into a trickling filter reaction bath(13). The wastewater discharged from the trickling filter reaction bath is inputted into the concrete structure.

Model Sensitivity Analysis for Biotrickling Filter Treatment of Graywater Simulant and Waste Gas. II

Abstract: A detailed sensitivity analysis was conducted to identify key parameters for a biotrickling filter simultaneously treating graywater and waste gas containing ammonia and hydrogen sulfide contaminants. Sampling-based approaches were applied to quantitatively assess the sensitivity of both design and intrinsic model parameters. Specifically, the sensitivity of contaminant removal rates under system conditions was investigated. Results suggested that contaminant removal rates can be substantially improved by increasing the fraction of wetted area in a biotrickling filter. Although recirculation flow rate is insensitive when considering liquid contaminant removal, increasing this parameter improves gas removal efficiency and also increases wetted area within the biotrickling filter. Reactor performance can also be improved by increasing gas and liquid residence times. Contaminant diffusivity through the biofilm is an important parameter and should be accurately assessed. This study differentiated key from insignificant biotrickling filter reactor design parameters for the biotrickling filter and provides guidance for similar research applications.

Treatment of Hydrogen Sulfide Odor by Bio-trickling Filter

Abstract: In order to dispose of H2S odor pollution,a long-term lab-scale deodorization experiment is carried out continuously by bio-trickling filter packed with ZX01 stuffingThe results show that the removal efficiency of H2S is nearly 100% and the optimum gas retention time is 30 s when inlet concentration of H2S is 300 mg/m3Metabolism product of H2S is mainly composed of SO42-The bio-reactor is not blocked in the experiment in which the resistance is maintained at lower valueThe bio-trickling filter needs not carry out a back washing frequently,and it can be operated steadily for a long term

Pilot-scale study of removal of anionic surfactants with trickling filter

Abstract: Anionic surfactants are wildly used in many industrial and household applications. Because anionic surfactants are used so widely, significant attention has focused on the removal of these contaminants from wastewater. Among various treatment techniques, biofiltration, such as trickling filter technologies, has been employed in many wastewater treatment plants (WWPTs) to remove anionic surfactants. However, current knowledge of the efficacy of trickling filter to remove anionic surfactants from wastewaters is limited. The present study characterized the performance of a high rate (i.e. roughing) trickling filter to remove anionic surfactants both at lab-scale and pilot-scale. Lab-scale tests investigated the biodegradation of anionic surfactants under controllable conditions were compared with those from previous studies by others. Pilot-scale tests investigated the efficacy of a trickling filter at removing anionic surfactants from a wastewater over an extended period of time. The data from the pilot-scale tests were used to model the performance of trickling filter at removing anionic surfactants from the wastewater, using first order and modified Velz models. The lab-scale tests indicated that high molecular weight anionic surfactants degrade faster than the low molecular weight surfactants. The biodegradation rates observed in the present study were similar to those from pervious studies by others. The pilot-scale tests indicated that roughing trickling filter could remove 11% to 29% of anionic surfactants and 4% to 22% of COD from the wastewater. Higher molecular weight anionic surfactants were more degradable. The experimental data could be accurately modeled using the modified Velz model (R 2 value more than 0.9). The degradation rates of modified Velz model for total anionic surfactants, high molecular weight anionic surfactants and COD were 0.053±0.0057, 0.088±0.0048 and 0.119±0.0111 (mIs) ° respectively.

Trickling filter device and use of trickling filter cover

Abstract: The trickling filter device for wastewater clarification plant, comprises a trickling filter (1) formed by a porous body, a trickling unit for trickling of wastewater over the filter, a filter cover for preventing penetration of atmospheric oxygen into the filter, and a trickling filter processor exhibiting a rotating sprinkler. The filter cover shows a parallel wastewater distributing groove sections with a lateral wastewater overflow edge, and cover section with lateral edge (8) arranged between the groove sections. The trickling filter device for wastewater clarification plant, comprises a trickling filter (1) formed by a porous body, a trickling unit for trickling of wastewater over the filter, a filter cover for preventing penetration of atmospheric oxygen into the filter, and a trickling filter processor exhibiting a rotating sprinkler. The filter cover shows a parallel wastewater distributing groove sections with a lateral wastewater overflow edge, cover section with lateral edge (8) arranged between the groove sections, adjascently arranged and collectively connected hollow bodies, and a rotating frame or two opposite reinforcement profiles to the storage or to the reinforcement of the filter device. The lateral edge projects from the cover section into the groove section. The groove section and cover section are formed by a single profile and are adjoined in mounted condition. The cover section is formed trapezoidal, V/U shaped or reversed in cross section. The sidewalls of the groove sections and the cover section are merged together with one another. The lateral cover sections are arranged at the rotating frame or the reinforcement profile. Filling materials are admitted into the groove sections of the filter and suspended from cover section of the material. The groove sections are arranged on the upper surface of the filter. The filter cover is formed as a hollow body with funnel- or groove shaped stamp. The depth of the stamping is larger than the half distance between the upper and lower surface of the hollow body. The hollow body shows a flat upper surface and lower surface. The hollow bodies are connected over a groove/spring system. An independent claim is included for a trickling filter cover for trickling filter device.

Evaluation of an enhanced magneto-chemical process for the removal of pathogens in wastewater

Abstract: New wastewater treatment technologies are a necessity as a result of increasingly stringent discharge standards, particularly concerning viruses. The traditional approach to wastewater treatment consists of biological treatment, such as trickling filters, biofilms, and activated sludge. Although these biological processes have been an adequate means of wastewater treatment, they are intrinsically limited by their biological nature. A magneto-chemical process, known as CoMag(TM), has been developed to improve coagulation and solids separation and expand upon conventional wastewater treatment techniques. The research objective of this project was to develop and evaluate a bench-scale model of the CoMag(TM) process for the removal of MS2, poliovirus type 1, rotavirus strain Wa, and adenovirus type 2 from secondary effluent wastewater, at 24°C and 4°C. Additionally, the removal of MS2 was assessed using a 100 gpm CoMag(TM) pilot plant. The results indicate that there was a statistically significant difference (when alpha=0.050) in the removal of MS2, when magnetite is added, versus when magnetite is not added. In addition, results suggest that MS2 was removed more effectively using the bench-scale model then the 100 gpm pilot plant. Employing the bench scale model, the mean Log Reduction Value for MS2, poliovirus type 1, rotavirus strain Wa and adenovirus type 2 was 2.9182, 3.3893, 3.5313, and 3.482 respectively. Moreover, there was no statistically significant difference in the removal of MS2, rotavirus strain Wa, and adenovirus type 2 at 24° and 4°C. There was, however, a statistically significant difference in the removal or poliovirus type 1 at 24° and 4°C. This research demonstrates that the CoMag(TM) process has the ability to achieve > 2 log removal of MS2 and >3 log removal of poliovirus type 1, rotavirus strain Wa and adenovirus type 2. Therefore, the CoMag(TM) process has the potential to aid wastewater and water treatment facilities meet their more stringent water quality permits.

A Pilot-Scale Odor Treatment Experiment of Hydrogen Sulfide by using Bio-Trickling Filter

Abstract: In order to investigate the removal efficiency of hydrogen sulfide (H2S) and adaptation of the bio-trickling filter to complicated on-site environment, deodorization experiment of H2S was carried out continuously in cold seasons by using the bio-trickling filter packed with fiber carrier. The results suggested that removal efficiency of H2S was higher than 99% when inlet volumetric loading of the bio-trickling filter was lower than 153 g/(m3-h) and the corresponding inlet concentration achieved 1275 mg/m in cold seasons. When effluent wastewater from secondary sedimentation tank was used as spray water that contained a small quantity of N (nitrogen), P (phosphorus) and other elements, the optimum spray water flow rates were 5.3, 7.5 and 9.5 L/h when inlet concentrations were 240, 450 and 1000 mg/m3, respectively. And meanwhile, the bio-trickling filter operated steadily and was not blocked during the experiments for nearly four months.