High-Rate Nitrification in a Biological Fluidized Bed

1990 ◽  
Vol 22 (1-2) ◽  
pp. 431-442 ◽  
Author(s):  
P. F. Cooper ◽  
S. C. Williams
Keyword(s):  
Fluidized Bed ◽  
Operating Cost ◽  
Operating Conditions ◽  
High Rate ◽  
Optimum Operating ◽  
Secondary Effluent ◽  
Below Ground ◽  
Demonstration Plant ◽  
Technical Evaluation ◽  
Volumetric Loading

The use of a Biological Fluidized Bed (BFB) was evaluated in a large demonstration plant for nitrification of a secondary effluent at Horley STW (South of London). The BFB was operated over a range of flows from 250→600 m3/d using effluents containing 25mg NH3-N/ℓ, 18mg BOD/ℓ to define the optimum operating conditions. It was possible to reduce from 27 down to 3mg NH3-N/ℓ in a contact time of only 38 mins (a volumetric loading of 1 kg NH3-N/m3.d). The unit was then operated under diurnal flow. A 20m deep below-ground downflow-bubble-contact oxygenator was used which was capable of dissolving 60mg 02/ℓ. Following the technical evaluation, an economic comparison was made between using the add-on nitrifying BFB against the option of extending an existing activated sludge plant. The BFB had a lower capital cost but higher operating cost. The BFB was shown to be cost competitive.

Biomass Oxygen-Enriched Gasification in a Pressurized Fluidized Bed for Production of Middle/High Heat-Value Fuel Gas

2013 ◽  
Vol 860-863 ◽  
pp. 450-455 ◽  
Author(s):  
Qian Liu ◽  
Bao Sheng Jin
Keyword(s):  
Fluidized Bed ◽  
Calorific Value ◽  
High Heat ◽  
Operating Conditions ◽  
National Standards ◽  
Optimum Operating ◽  
Hydrocarbon Synthesis ◽  
Fuel Gas ◽  
Equivalent Ratio ◽  
Heat Value

For biomass gasification, the high tar and carbon monoxide contents and the low heat value of fuel gas are problems to be solved, which leading to the poor operating conditions of the completed projects in China. Therefore, a new technology of biomass oxygen-enriched gasification in pressurized fluidized bed is proposed. Coupling the technologies of pressurized biomass oxygen-enriched gasification at low temperature, high-temperature gasification and melting, steam reforming and hydrocarbon synthesis, the high gasification efficiency, tar cracking and gas reforming shall be realized, and the middle/high heat value gas which meets the national standards will be produced. ASPEN PLUS simulation was carried out for biomass oxygen-enriched gasification. Both the equivalent ratio and gas yield of rice husk are lower than that of the wood sawdust, while the gas calorific values are equivalent. Considering the gas yield, the calorific value and economy, the optimum operating conditions are obtained: the gasification temperature at 1200 °C, the oxygen purity at 0.9, the equivalent ratio at about 0.25, the S/B ratio at 0.1~0.2. The gas yield could reach 1.9 m3/kg, and the gas calorific value was above 11 MJ/m3.

Optimization of Continuously Stirred Tank Bioreactor Design for Cost Minimization: Effect of Microbial Species and Operating Conditions

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Erin E Powell ◽  
Gordon A Hill
Keyword(s):  
Culture Medium ◽  
Operating Cost ◽  
Oxygen Demand ◽  
Design Strategy ◽  
Aeration Rate ◽  
Operating Conditions ◽  
Stirred Tank ◽  
Optimum Operating ◽  
Stirred Tank Bioreactor ◽  
Microbial Species

The operation of continuously stirred tank bioreactors (CSTBs) at minimum cost is a major concern of operators. In this work, a CSTB design strategy is presented where impeller stirring speed and aeration rate are optimized to meet the oxygen demand of growing cells, simultaneously minimizing the capital and operating cost. The operating cost is limited to the cost of utilities. The optimization scheme assumes a given fermentor tank size, and that the properties of the culture medium and the oxygen respiratory requirements of the microorganisms being cultivated are known. It is possible to choose between two different turbine impellers during the design process. The equations, constraints, and the CSTB design strategy employed by the program are described. The effect of microbial species, ions in the culture medium, impeller style, as well as changing CSTB size and biomass input density on the optimum operating conditions, is examined. The mass transfer coefficient, gas holdup, mixing speed, and aeration rate are all reported at optimized cost conditions. A study of the effects of various parameters on the CSTB design are shown.

scholarly journals Demulsification Treatment of Spent Metalworking Fluids by Metal Cations: The Synergistic Effect and Efficiency Evaluation

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1807
Author(s):  
Yanqing Zhang ◽  
Lingxue Wu ◽  
Xiaochen Zhang ◽  
Baoxin Ge ◽  
Yuanfeng Qi
Keyword(s):  
Reaction Time ◽  
Synergistic Effect ◽  
Metal Ions ◽  
Metal Ion ◽  
Operating Cost ◽  
Operating Conditions ◽  
Metalworking Fluids ◽  
Optimum Operating ◽  
Efficiency Evaluation ◽  
Automobile Parts

In this paper, various metal ions were utilized for the demulsification of spent metalworking fluids discharged from an automobile parts workshop. Five types of metal ions, i.e., Fe3+, Al3+, Fe2+, Ca2+ and Mg2+, combined with coagulant were systematically evaluated, and the synergistic effect as well as the optimum operating conditions were studied. The results indicated that the Ca2+ as well Mg2+ possessed hardly efficiency for the demulsification, on the contrary, Fe2+ reduced the yield of the by-product sludge and lowered the SV30 ratio, and Al3+ boosted the CODCr removal. Furthermore, Fe3+ and Al3+ had a significant synergistic effect to achieve a better transmittance and a higher CODCr/SV30 ratio which revealed that more CODCr was removed, as well as less by-product sludge was generated. For a better demulsification of spent metalworking fluids, the optimum operating conditions were gathered as follows: the dosage of metal ions was 0.08 mol/L with Al3+:Fe3+ ratio was 1.5:1, the reaction pH was 6.00, the reaction time was 18.00 min and the temperature was 323.00 K. Based on this, the CODCr removal, the SV30 ratio and the transmittance and CODCr/SV30 ratio of the spent metalworking fluids were 80.21%, 40.00%, 95.20% and 128.33 mg/mL, respectively. This combined metal ion demulsification method possessed an advantageous minimization of spent metalworking fluids, which greatly benefited the automobile parts workshops in cutting down the operating cost in environmental protection.

A Pilot-Scale Evaluation of the ‘Biocarbone Process' for the Treatment of Settled Sewage and for Tertiary Nitrification of Secondary Effluent

1990 ◽  
Vol 22 (1-2) ◽  
pp. 305-316 ◽  
Author(s):  
G. R. Dillon ◽  
V. K. Thomas
Keyword(s):  
Sewage Treatment ◽  
Pilot Scale ◽  
Economic Feasibility ◽  
High Rate ◽  
Secondary Effluent ◽  
Scale Evaluation ◽  
Loading Rates ◽  
N Removal ◽  
The Uk ◽  
Volumetric Loading

The BIOCARBONE process is a recently developed method for wastewater treatment. High concentrations of active biomass attach to an expanded shale medium in an aerated, packed-bed filter. High-rate biological treatment and in-situ removal of suspended solids are claimed as advantages of the process. The pilot-scale evaluation aimed to assess the performance of the process and its economic feasibility for use in the UK. Carbonaceous oxidation of settled sewage and tertiary nitrification of secondary effluent were investigated in two pilot-scale reactors. Carbonaceous oxidation produced a good-quality effluent at volumetric loading rates up to 4.1 kg BOD5/m3.d (9.2 kg COD/m3,d). Automatic backwashing of the filter was required and problems were encountered with blockages of the process aeration grid. Tertiary nitrification achieved greater than 90% ammoniacal nitrogen (NH3-N) removal at volumetric loading rates up to 0.58 kg NH3-N/m3.d (0.63 kg KJN/m3.d). The economic evaluation indicated that costs of sewage treatment using the BIOCARBONE process would be comparable to those of the activated sludge process for sewage treatment works greater than 50,000 population equivalent. The results show that the BIOCARBONE process is suitable for both the carbonaceous oxidation of settled sewage and the tertiary nitrification of secondary effluent. The process may be an economic option for large sewage treatment works in the UK.

scholarly journals Application of a multiple criteria analysis for the selection of appropriate radical based processes in treatment of car wash wastewater

2020 ◽  
Vol 26 (2) ◽  
pp. 200115-0
Author(s):  
Elif DURNA ◽  
Nevim GENÇ
Keyword(s):  
Operating Cost ◽  
Operating Conditions ◽  
Cod Removal ◽  
Optimum Operating ◽  
Combined Processes ◽  
Preference Order ◽  
Effective Parameters ◽  
Pareto Analysis ◽  
Car Wash ◽  
Car Wash Wastewater

In this study, the treatment of car wash wastewater was investigated by radical based hybrid/combined processes. Proposed processes, (Microwave (MW) + persulfate (PS) + Electrocoagulation (EC)), (ozone (O3) + PS + EC) and (MW + PS + O3), were optimized with Taguchi orthogonal array technique for maximum COD removal. The COD removal under optimum conditions was obtained to be 84%, 64.9% and 61.4%, for (MW + PS+ EC), (O3 + PS+ EC) and (MW + PS+ O3) processes, respectively. Operating costs for (MW + PS + EC), (O3 + PS + EC) and (MW + PS + O3) processes have been calculated as 0.2614, 0.1335 and 0.2653 €/L wastewater under optimum operating conditions. Pareto analysis showed that MW time and PS dose are very effective parameters but especially ozone related parameters have no significant effect on COD removal. Processes were evaluated with the PROMETHEE approach in terms of treatment efficiency, operating cost, sludge formation, and preferability criteria to determine the most suitable among the three alternative processes. As a result, the preference order of the processes for the treatment of car wash wastewater with radical based treatment processes was found as (MW + EC + PS) > (MW + O3 + PS) > (O3 + EC + PS).

scholarly journals Removal of COD and BOD from biologically treated municipal wastewater by electrochemical treatment

2013 ◽  
Vol 5 (2) ◽  
pp. 475-481 ◽  
Author(s):  
Arun Kumar Sharma ◽  
A. K. Chopra
Keyword(s):  
Municipal Wastewater ◽  
Operating Cost ◽  
Operating Time ◽  
Sewage Treatment Plant ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Initial Ph ◽  
Treated Municipal Wastewater ◽  
Maximum Removal

The present investigation observed the effect of current density (CD), operating time (OT), inter electrode distance (IED), electrode area (EA), initial pH and settling time (ST) using Fe-Fe electrode combination on the removal of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) from biologically treated municipal wastewater (BTMW) of Sewage Treatment Plant (STP). The maximum removal of COD (92.35%) from BTMW was found with the optimum operating conditions of CD (2.82 A/m2), OT (40 mins.), IED (0.5 cm), EA (160 cm2), initial pH (7.5) and ST (60 min.), while the maximum removal of BOD (84.88%) was found with the ST (30 min.) at the same operating conditions. There was no need of pH adjustment of the BTMW during ET as the optimal removal efficiency was close to the pH of 7.5. Under optimal operating conditions, the operating cost was found to be 54.29 Rs./m3 / 1.08 US$/m3 in terms of the electrode consumption (78.48 x 10-5 kg Al/m3 ) and energy consumption (108.48 Kwh/m3).

On Site High Rate UASB Anaerobic Demonstration Plant Treatment of NSSC Wastewater

1988 ◽  
Vol 20 (1) ◽  
pp. 87-97 ◽  
Author(s):  
L. H. A. Habets ◽  
M. H. Tielbaard ◽  
A. M. D. Ferguson ◽  
C. F. Prong ◽  
A. J. Chmelauskas
Keyword(s):  
Pilot Plant ◽  
Granular Sludge ◽  
Full Scale ◽  
Operating Conditions ◽  
High Rate ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Study Results ◽  
Wastewater Quality ◽  
Demonstration Plant

Results of a 19 m3 demonstration plant studies are summarized. The plant is located at Sturgeon Falls at a NSSC mill and hardboard plant owned by MacMillan Bloedel. The mill discharges 6300 m3/day of waste effluent containing 50 tonnes of BOD and 127 tonnes of COD. Lab scale testing (1983) and an 18 month 1.4 m3 reactor volume pilot plant study (1985) were completed confirming treatability of the wastewater and suitability of the Upflow Anaerobic Sludge Blanket (UASB) technology among others to successfully treat the mill wastewater. Discharged effluent contains spent sulphite liquor and primary clarifier effluent. As required, the 1.4 m3 Biopaq System successfully achieved BOD reductions in excess of 75 percent at loadings greater than 10 kg COD/m3.d. As a consequence of this and because of economic considerations, the Biopaq System of Paques-Lavalin was selected for on site demonstration during a 12 months period. This period started in spring 1986. Erection of a full-scale plant is planned to take place in 1988. The purpose of the on site demonstration study is to confirm wastewater treatability, optimize design loading rates and confirm granular sludge growth. To achieve the objectives and simulate full-scale operating conditions the MacMillan Bloedel pilot plant has been automated and is controlled via a microprocessor incorporating a customized software program. Start-up performance results and operation at incremental loadings under steady state conditions are presented together with the experience gained during extreme variations in mill effluent quality and flow. Preliminary study results from the first 10 months disclose that a BOD removal efficiency of 80 percent or better is achieved at weekly average loadings of 15 kg COD/m3.d, and the process offers strong resilience to daily swings in wastewater quality. The results also show a net accumulation of granular sludge. The practical application of this technology from a mill operating perspective is discussed, and the layout for a full-scale installation with projected capital and operating costs is provided. Most of the contents of this paper was presented at the Tappi 1987 Environmental Conference (Prong etal, 1987). This paper presents the latest results.

scholarly journals Fouling Removal of UF Membrane with Coated TiO2Nanoparticles under UV Irradiation for Effluent Recovery during TFT-LCD Manufacturing

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
S. H. You ◽  
C. T. Wu
Keyword(s):  
Uv Irradiation ◽  
Membrane Fouling ◽  
Liquid Crystal Display ◽  
Membrane Surface ◽  
Thin Film Transistor ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Secondary Effluent ◽  
Operating Pressure ◽  
Permeate Flux

An ultrafiltration (UF) membrane process was employed to treat the secondary effluent discharged from a manufacturing of thin film transistor-liquid crystal display (TFT-LCD) in this study. A bench-scale system was performed to evaluate the fouling removal of a UF membrane with coated titanium dioxide (TiO2) nanoparticles under UV irradiation. The operating pressure and feed temperature were controlled at 300 KN/m2and 25°C, respectively. It was found that the optimum operating conditions were attained with TiO2concentrations of 10 wt% for both 5 KD and 10 KD MWCO. Continuous UV irradiation of 5 KD MWCO improved the permeate flux rate from 45.0% to 59.5% after 4 hours of operation. SEM-EDS analysis also showed that the photocatalytic effect had reduced the average thickness of cake fouling on the membrane from 6.40 μm to 2.70 μm for 5 KD MWCO and from 6.70 μm to 3.1 μm for 10 KD MWCO. In addition, the membrane contact angle was reduced from 54° to 44°. The photocatalytic properties of TiO2apparently increased the hydrophilicity of the membrane surface, thereby reducing membrane fouling.

Prediction of optimum operating conditions of liquid fluidized bed systems

1997 ◽  
Vol 75 (2) ◽  
pp. 327-332 ◽  
Author(s):  
M. Jamialahmadi ◽  
M. R. Malayeri ◽  
H. Müller-Steinhagen
Keyword(s):  
Fluidized Bed ◽  
Operating Conditions ◽  
Optimum Operating
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