Theoretical Study on Two-Stage Anaerobic-Aerobic Biological Treatment of a CTMP Effluent

1996 ◽  
Vol 31 (1) ◽  
pp. 1-20 ◽  
Author(s):  
H.W. Liu ◽  
S.N. Lo ◽  
H.C. Lavallée
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Operating Conditions ◽  
Time Range ◽  
Two Stage ◽  
Cell Age ◽  
Initial Substrate ◽  
Stage System ◽  
Basic Equations ◽  
Monod Kinetic

Abstract Basic equations based upon the Monod kinetic model are presented for a two-stage, sequential anaerobic-aerobic treatment system. The effects of operating conditions, such as hydraulic retention time, mean cell age, concentration of microorganisms and initial substrate concentration, on the behaviour of the two-stage system for the treatment of a CTMP effluent were studied theoretically. This was done in terms of removal of BOD5 and RFA, and sensitivity to changes in operating conditions. The study revealed that unstable operation of the anaerobic process could be due to the treatment being carried out in a time range in which the operation was very sensitive to the variation in either hydraulic retention time or mean cell age.

scholarly journals Effect of Influent pH and Hydraulic Retention Time on Bioelectricity Generation in an Integrated Acidogenic Reactor and Microbial Fuel Cell Treating Rice Mill Wastewater

2021 ◽  
Author(s):  
Aryama Raychaudhuri ◽  
Manaswini Behera
Keyword(s):  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Integrated System ◽  
Operating Conditions ◽  
Electricity Production ◽  
Two Stage ◽  
Bioelectricity Generation ◽  
Rice Mill Wastewater

Abstract An innovative design approach was employed in the present study to enhance the electricity generation and wastewater treatment in a microbial fuel cell (MFC). A dual-chambered MFC with a ceramic separator was coupled with an acidogenic chamber. Acidogenic bioconversion of rice mill wastewater into volatile fatty acid (VFA) represents an interesting approach for wastewater valorization. The VFA containing effluent could be used as an effective substrate for bioelectricity generation in MFCs. A short hydraulic retention time (HRT) can be used for the two-stage anaerobic process (acidogenesis and electrogenesis), thus preventing the proliferation of methanogens. The effect of pH (5.5–7.5) and HRT (0.5 d–0.75 d) were investigated to understand the influence of operational parameters on the performance of the integrated system. The maximum VFA concentration of 1065.15 ± 5.08 mg COD/L was achieved at pH 7.5 and HRT 0.5 d. Under these operating conditions, the general activity of acid-forming microorganisms and exoelectrogens improved remarkably, and the power density obtained from the system was 4.72 ± 0.10 W/m3. The current research indicates excellent potential for simultaneous treatment and electricity production from rice mill wastewater. The use of low-cost, locally manufactured, and customized membranes and the two-stage treatment can pave the way for the practical application of this technology.

scholarly journals Effect of Hydraulic Retention Time on Carbon Sequestration during the Two-Stage Anammox Process

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 717 ◽  
Author(s):  
Xueyan Ma ◽  
Xiaoning Liu ◽  
Bangdong Xiang ◽  
Wenjie Zhang
Keyword(s):  
Carbon Sequestration ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Calvin Cycle ◽  
Nitrogen Loading ◽  
Operating Conditions ◽  
Partial Nitrification ◽  
Ammonium Oxidation ◽  
Two Stage ◽  
Anammox Process

In a biological treatment process, hydraulic retention time (HRT) has a certain effect on the operation of the reactor. This study investigated the effect of HRT on carbon sequestration in a two-stage anaerobic ammonium oxidation (anammox) process using a partial nitrification reactor and anammox reactor to determine the optimal carbon sequestration operating conditions. Molecular biotechnology was used to analyze the sludge in the reactor in order to explore the denitrification performance and to determine the carbon sequestration pathway of the microorganisms. The results show that the partial nitrification stage had the highest carbon sequestration rate (0.319 mg/mg·N) when the nitrogen loading rate (NLR) was 0.44 kg·N/m3/d. The NLR of the anammox stage was 0.13 kg·N/m3/d. When the HRT was 33.4 h, the carbon sequestration of the anammox reaction was at its highest, reaching 0.183 mg/mg·N. The results of microbial analysis show that the carbon-fixing gene cbbLR1 was present in the sludge samples during the anammox and partial nitrification stages, and that there was a Calvin cycle carbon sequestration pathway during the growth process. However, the existence of a gene for reducing and immobilizing CO2 by the acetyl-CoA pathway was not detected; further research is thus needed.

Effect of hydraulic retention time on pretreatment of blended municipal sludge

2011 ◽  
Vol 64 (4) ◽  
pp. 967-973
Author(s):  
S. Koyunluoglu-Aynur ◽  
R. Riffat ◽  
S. Murthy
Keyword(s):  
Retention Time ◽  
Volatile Fatty Acids ◽  
Hydraulic Retention Time ◽  
Operating Conditions ◽  
Methane Yield ◽  
Municipal Sludge ◽  
Volatile Solids ◽  
Significant Difference ◽  
Autothermal Thermophilic Aerobic Digestion ◽  
Pretreatment Processes

The objective of the present work was to evaluate the effect of hydraulic retention time (HRT) on hydrolysis and acidogenesis for the pretreatment processes: acid phase digestion (APD) and autothermal thermophilic aerobic digestion (ATAD) using blended municipal sludge. The effect of the different pretreatment steps on mesophilic anaerobic digestion (MAD) was evaluated in terms of methane yield, keeping the operating conditions of the MAD the same for all systems. Best operating conditions for both APD and ATAD were observed for 2.5 d HRT with high total volatile fatty acids (tVFA), and the highest methane yield observed for MAD. No significant difference was observed between the two processes in terms of overall volatile solids (VS) reduction with same total HRT. The autothermal process produced heat of 14,300 J/g VS removed from hydrolytic and acetogenic reactions without compromising overall methane yields when the HRT was 2.5 d or lower and the total O2 used was 0.10 m3 O2/g VS added or lower. However, the process needs the input of oxygen and engineering analysis should balance these differences when considering the relative merits of the two pretreatment processes. This is the first study of its kind directly comparing these two viable pretreatment processes with the same sludge.

scholarly journals Continuous electrochemical reactor improved by the addition of Moringa oleífera lam extract: optimization of operational conditions for Blue 5G dye removal

2019 ◽  
Vol 14 (3) ◽  
pp. 1
Author(s):  
Bruna Souza dos Santos ◽  
Eduardo Eyng ◽  
Paulo Rodrigo Stival Bittencourt ◽  
Laercio Mantovani Frare ◽  
Éder Lisandro de Moraes Flores ◽  
...  
Keyword(s):  
Retention Time ◽  
Moringa Oleifera ◽  
Hydraulic Retention Time ◽  
Operating Conditions ◽  
Current Intensity ◽  
Quadratic Model ◽  
Residual Concentration ◽  
Natural Coagulant ◽  
Operational Conditions ◽  
Moringa Oleifera Lam

Wastewaters from textile industries are known for their difficulty to treat, several alternative technologies are applied for their treatment. In this context, the study examined a hybrid treatment system, composed of electrocoagulation combined with a natural coagulant (extract of Moringa oleífera lam seeds) to remove reactive dye Blue 5G aqueous solutions. The work evaluated the use of milder operating conditions to improve the efficiency of treatment, with reduced demands for electrical power and coagulant.  The following factors were evaluated: electric current intensity, natural coagulant concentration and hydraulic retention time. A quadratic model was adjusted and validated at a 5% significance level. The overall optimization resulted in conditions of 0.28 A for electrical current intensity, 1000.00 mg L-1 of aqueous extract of Moringa oleífera lam and 5 min for hydraulic retention time. While operating under optimal conditions, the removal of 71.38% of color and 5.22 mg L-1 of iron residual concentration was achieved.

scholarly journals The Impact of Hydraulic Retention Time on the Biomethane Production from Palm Oil Mill Effluent (POME) in Two-Stage Anaerobic Fluidized Bed Reactor

2020 ◽  
Vol 10 (1) ◽  
pp. 11-16
Author(s):  
Laily Isna Ramadhani ◽  
Sri Ismiyati Damayanti ◽  
Hanifrahmawan Sudibyo ◽  
Muhammad Mufti Azis ◽  
Wiratni Budhijanto
Keyword(s):  
Fluidized Bed ◽  
Palm Oil ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Ph Control ◽  
Palm Oil Mill Effluent ◽  
Two Stage ◽  
Second Stage ◽  
Biomethane Production ◽  
Palm Oil Mill

Indonesia is currently the most significant crude palm oil (CPO) producer in the world. In the production ofCPO, 0.7m3 of Palm Oil Mill Effluent (POME) is emitted as the wastewater for every ton of fresh fruit bunches processed in the palm oil mill.With the increasing amount of CPO production, an effective POME treatment system is urgently required to prevent severe environmental damage. The high organic content in the POME is a potential substrate forbio-methane production. The biomethane production is carried out by two groups of microbes, i.e., acidogenic and methanogenic microbes. Each group of bacteria performs optimally at different optimum conditions. To optimize the biomethane production, POME was treated sequentially by separating the acidogenic and methanogenic microbes into two stages of anaerobic fluidized bed reactors (AFBR). The steps were optimized differently according to the favorable conditions of each group of bacteria. Although perfect separation cannot be achieved, this study showed that pH control could split the domination of the bacteria, i.e., the first stage (maintained at pH 4-5) was dominated by the acidogenic microbes and the second stage (kept neutral) was governed by methanogens. In addition to the pH control, natural zeolitewas added as microbial immobilization media in the AFBR to improve the performance of the microorganisms, especially in preventing microbial wash out at short hydraulic retention time (HRT). This study was focused on the understanding of the effect of HRT on the performance of steady-state continuous AFBR. The first stage as the acidogenic reactorwas rununder acidic conditions (pH 4-5) at five different HRTs. In comparison, the second stage as the methanogenic reactorwasrun under the neutral condition at four different HRTs. In this work,short HRT (5 days) resulted in better performance in both acidogenic AFBR and methanogenic AFBR. The immobilization media was hence essential to reduce the risk of washout at such a short HRT. The two-stage system also resulted in quite a high percentage of soluble chemical oxygen demand (sCOD) removal, which was as much as 96.06%sCOD.

Impact of Hydraulic Retention Time at Constant Organic Loading Rate in a Two-Stage Expanded Granular Sludge Bed Reactor

2014 ◽  
Vol 31 (6) ◽  
pp. 317-323 ◽  
Author(s):  
Mahyar Ghorbanian ◽  
Robert M. Lupitskyy ◽  
Jagannadh V. Satyavolu ◽  
R. Eric Berson
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Loading Rate ◽  
Granular Sludge ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Two Stage

scholarly journals Experimental Research of Fibrous Materials for Two-Stage Filtration of the Intake Air of Internal Combustion Engines

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7166
Author(s):  
Tadeusz Dziubak ◽  
Leszek Bąkała ◽  
Sebastian Dominik Dziubak ◽  
Kamil Sybilski ◽  
Michał Tomaszewski
Keyword(s):  
Pressure Drop ◽  
Absorption Coefficient ◽  
Internal Combustion Engines ◽  
Filter Material ◽  
Internal Combustion ◽  
Operating Conditions ◽  
Combustion Engines ◽  
Two Stage ◽  
Stage System ◽  
Dust Absorption

Pollutant properties in intake air to internal combustion engines were analyzed. Mineral dust particles’ influence on accelerated engine components’ wear was discussed. Dust concentration values in the air under various operating conditions in trucks and special vehicles were presented. The idea and necessity for using two-stage filters, operating in a “multi-cyclone–porous partition” system for vehicles operated in dusty air conditions, are presented. Information from the literature information has been presented, showing that impurities in small grain sizes reduce fiber bed absorbency. It has been shown that such a phenomenon occurs during filter material operation, located directly behind the inertial filter (multi-cyclone), which off-road vehicles are equipped with. It results in a greater pressure drop intensity increase and a shorter proper filter operation period. It has been shown that filter material selection for the motor vehicle air filter requires knowledge of the mass of stopped dust per filtration unit area (dust absorption coefficient km) determined for a given permissible resistance value Δpfdop. It has been shown that there is no information on absorption coefficient values for filter materials operating in a two-stage “multi-cyclone–porous partition” separation system. Original methodology and conditions for determining dust absorption coefficient (km) of a separation partition, operating under the conditions of two-stage filtration, were presented. The following characteristics were tested: separation efficiency, filtration performance, and pressure drop characteristics of three different filtration partitions. These were A (cellulose), B (cellulose and polyester), and C (cellulose, polyester, and nanofibers layer), working individually and in a two-stage system—behind the cyclone. Granulometric dust composition dosed into the cyclone and cyclone downstream was determined. During tests, conditions corresponding to air filter’s actual operating conditions, including separation speed and dust concentration in the air, were maintained. For the pressure drop values, the dust absorption coefficient (km) values of three different filtration partitions (A, B, and C), working individually and in a two-stage system—behind the cyclone—were determined experimentally.

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