Influence of important operational parameters on performance of a membrane biological reactor

2000 ◽  
Vol 41 (10-11) ◽  
pp. 235-242 ◽  
Author(s):  
S-H. Yoon ◽  
H-S. Kim ◽  
J-K. Park ◽  
H. Kim ◽  
J-Y. Sung
Keyword(s):  
Removal Efficiency ◽  
Feeding Rate ◽  
Peristaltic Pump ◽  
Operational Parameters ◽  
High Concentration ◽  
Entire Process ◽  
Bench Scale ◽  
N Removal ◽  
Series Of Experiments ◽  
Bod Removal

In order to elucidate optimum operational parameters, five series of experiments with bench scale “A/O and MBR (membrane biological reactor)” devices were carried out. The HRTs of each anoxic and oxic bioreactor were maintained for 2˜6 h and for 3˜6 h, respectively. The internal recycle ratios were also changed from 100% to 300% of the influent feeding rate by peristaltic pump. There were no recognizable differences in the values of BOD removal efficiency, being around 99%, in the series of experiments. The same was true for T–N removal efficiency, which ranged about 60%. The similarity of the serial experiments for each parameter indicates that the extraordinarily high concentration of microorganisms in the bioreactor, i.e. 10,000–15,000 mg/l, strongly controls the entire process regardless of any moderate changes of the operational parameters.

Performance of permeable media rotating reactors used for pretreatment of wastewaters

2014 ◽  
Vol 69 (9) ◽  
pp. 1926-1931 ◽  
Author(s):  
F. Hassard ◽  
E. Cartmell ◽  
J. Biddle ◽  
T. Stephenson
Keyword(s):  
Removal Efficiency ◽  
Removal Rate ◽  
Ammonia Removal ◽  
High Rate ◽  
Organic Loading Rate ◽  
Carbonaceous Materials ◽  
Bench Scale ◽  
Permeable Media ◽  
N Removal ◽  
The Impact

The impact of organic loading rate (OLR) on carbonaceous materials and ammonia removal was assessed in bench scale rotating media biofilm reactors treating real wastewater. Media composition influences biofilm structure and therefore performance. Here, plastic mesh, reticulated coarse foam and fine foam media were operated concurrently at OLRs of 15, 35 and 60 g sCOD m−2d−1 in three bench scale shaft mounted advanced reactor technology (SMART) reactors. The sCOD removal rate increased with loading from 6 to 25 g sCOD m−2d−1 (P < 0.001). At 35 g BOD5m−2d−1, more than double the arbitrary OLR limit of normal nitrifying conditions (15 g BOD5m−2d−1); the removal efficiency of NH4-N was 82 ± 5, 27 ± 19 and 39 ± 8% for the mesh, coarse foam and fine foam media, respectively. Increasing the OLR to 35 gm−2d−1 decreased NH4-N removal efficiency to 38 ± 6, 21 ± 4 and 21 ± 6%, respectively. The mesh media achieved the highest stable NH4+-N removal rate of 6.5 ± 1.6 gm−2d−1 at a sCOD loading of 35 g sCOD m−2d−1. Viable bacterial numbers decreased with increasing OLR from 2 × 1010–4 × 109 cells per ml of biofilm from the low to high loading, suggesting an accumulation of inert non-viable biomass with higher OLR. Increasing the OLR in permeable media is of practical benefit for high rate carbonaceous materials and ammonia removal in the pretreatment of wastewater.

Ammonium nitrogen removal in batch cultures treating digested piggery wastewater with microalgae Oedogonium sp.

2013 ◽  
Vol 68 (2) ◽  
pp. 269-275 ◽  
Author(s):  
Haiping Wang ◽  
Zhiquan Hu ◽  
Bo Xiao ◽  
Qunpeng Cheng ◽  
Fanghua Li
Keyword(s):  
Removal Efficiency ◽  
Nutrient Removal ◽  
Scenedesmus Obliquus ◽  
Ammonium Nitrogen ◽  
High Concentration ◽  
Piggery Wastewater ◽  
Batch Tests ◽  
N Removal ◽  
Performance Reduction ◽  
Digested Piggery Wastewater

Due to the nutrient characteristics of the high concentration of available ammonium in digested piggery wastewater (DPW), microalgae can be used to treat DPW before its final discharge. Four green microalgae (Hydrodictyaceae reticulatum Lag, Scenedesmus obliquus, Oedogonium sp. and Chlorella pyrenoidosa) and three blue-green algae (Anabaena flos-aquae, Oscillatoria amoena Gom and Spirulina platensis) were used to remove the nutrients (N, P, C), especially ammonium nitrogen (NH4+-N), from diluted DPW with 300 mg/L algae density in batch tests. The microalgae with the best NH4+-N nutrient removal was then selected for further optimization of the variables to improve NH4+-N removal efficiency using a central composite design (CCD) experiment. Taking into account the nutrient removal efficiency, Oedogonium sp. showed the best performance (reduction of 95.9% NH4+-N, 92.9% total phosphorus (TP) and 62.5% chemical oxygen demand (COD)) based on the results of the batch tests. The CCD results suggested that the optimal values of variables were initial Oedogonium sp. density of 399.2 mg/L and DPW diluted by 16.3, while the predicted value of NH4+-N removal efficiency obtained was 97.0%.

Long-Term Assessment of 1,4-Dioxane Uptake via Duckweed with Emphasis on Operational Parameters

2020 ◽  
Vol 1008 ◽  
pp. 121-127
Author(s):  
Rania Osama ◽  
Mona G. Ibrahim ◽  
Ahmed Elreedy ◽  
Manabu Fujii
Keyword(s):  
Removal Efficiency ◽  
Lemna Gibba ◽  
Operational Parameters ◽  
High Solubility ◽  
Activated Carbon Adsorption ◽  
Physicochemical Processes ◽  
Carbon Adsorption ◽  
N Removal ◽  
Duckweed Pond

Duckweed (Lemna Gibba) was successfully used for phytoremediation of wastewater containing 1,4-dioxane, which could also result in biomass with high protein and carbon content. 1,4-dioxane is not easily removed or separated from wastewater by traditional physicochemical processes such as coagulation and activated carbon adsorption because of its high solubility [1]. Three duckweed-pond continual streams (DWs) lab-scale reactors, i.e., one pond (DW1), two ponds (DW2), and three ponds (DW3), were operated at variable hydraulic retention times (HRTs) of 2, 4, and 6 days respectively that are designed to treat wastewater containing 1,4dioxane. The results showed that the removal efficiency of 1,4 dioxane, COD, TOC, and ammonia were quite high in the DW3 which had the highest removal efficiency in 1,4-dioxane and NH4-N. 1,4-Dioxane and NH4-N removal efficiencies using DW3 (i.e., 56.9 ± 25% and 87.2 ± 7.1%, respectively) were slightly higher than that obtained using DW2 (i.e., 44.8 ± 19.6% and 81.9 ± 8.6%, respectively). Further, it was noted that, at DW3, the average effluent pH decreased that range from (8.80) to (7.45, c (TDS) decreased that range from( 921.5 ± 120.6) to (837.6 ± 83.6) mg/L, and Dissolved Oxygen (DO) increased that range from (3.5 ± 1.9) to (7.5 ± 3) mg/L. Eventually, DW removed 1,4dioxane effectively from wastewater, representing an effective, low operation, eco-friendly, and maintenance costs technology.

scholarly journals Electrochemical treatment of spent tan bath solution for reuse

2016 ◽  
Vol 8 (1) ◽  
pp. 123-134
Author(s):  
Amel Benhadji ◽  
Mourad Taleb Ahmed ◽  
Hayet Djelal ◽  
Rachida Maachi
Keyword(s):  
Removal Efficiency ◽  
Contact Time ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Electrochemical Treatment ◽  
Optimum Operating ◽  
Operational Parameters ◽  
High Concentration ◽  
Leather Processing ◽  
Chromium Salt

Abstract A spent tanning bath contains high concentration of salts, chromium and protein. The treatment system for removal of chlorides or chromium from this effluent is expensive. In this context this waste has to be reused. Our study focuses on the application of advanced oxidation processes for protein removal present in a tanning bath. To improve the quality of the chromium tanning bath, two electrochemical processes (electrooxidation and peroxi-electrocoagulation process, PEP) are investigated in a batch reactor. The effects of operational parameters such as reactor configuration, current density and electrolysis time on chemical oxygen demand (COD) and protein removal efficiency are examined. Results indicated that under the optimum operating range for process, the COD and protein removal efficiency reached 53 and 100%, respectively. The optimum values are determined for the hybrid process (PEP) under 0.13 A·cm−2 over 2 h. The treated tanning bath is used as a tanning solution in leather processing. The influence of chromium salt dose, pH solution, stirring time and contact time on the leather characteristic is evaluated. The hides tanned after the addition of 0.25% of commercial chromium salt, at pH solution, leaving them stirring for 4 h with a contact time of 2 days, and showed good hydrothermal stability and physical characteristics of leather.

scholarly journals Inorganic Nitrogen Production and Removal along the Sediment Gradient of a Stormwater Infiltration Basin

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 320
Author(s):  
Qianyao Si ◽  
Mary G. Lusk ◽  
Patrick W. Inglett
Keyword(s):  
Removal Efficiency ◽  
N Mineralization ◽  
Inorganic Nitrogen ◽  
Dry Season ◽  
Pollutant Removal ◽  
Net N Mineralization ◽  
Wet Season ◽  
Inorganic N ◽  
N Removal ◽  
Stormwater Infiltration

Stormwater infiltration basins (SIBs) are vegetated depressions that collect stormwater and allow it to infiltrate to underlying groundwater. Their pollutant removal efficiency is affected by the properties of the soils in which they are constructed. We assessed the soil nitrogen (N) cycle processes that produce and remove inorganic N in two urban SIBs, with the goal of further understanding the mechanisms that control N removal efficiency. We measured net N mineralization, nitrification, and potential denitrification in wet and dry seasons along a sedimentation gradient in two SIBs in the subtropical Tampa, Florida urban area. Net N mineralization was higher in the wet season than in the dry season; however, nitrification was higher in the dry season, providing a pool of highly mobile nitrate that would be susceptible to leaching during periodic dry season storms or with the onset of the following wet season. Denitrification decreased along the sediment gradient from the runoff inlet zone (up to 5.2 μg N/g h) to the outermost zone (up to 3.5 μg N/g h), providing significant spatial variation in inorganic N removal for the SIBs. Sediment accumulating around the inflow areas likely provided a carbon source, as well as maintained stable anaerobic conditions, which would enhance N removal.

scholarly journals Start-up Strategies for Anaerobic Ammonia Oxidation (Anammox) in In-Situ Nitrogen Removal from Polluted Groundwater in Rare Earth Mining Areas

2021 ◽  
Vol 13 (8) ◽  
pp. 4591
Author(s):  
Shuanglei Huang ◽  
Daishe Wu
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Ex Situ ◽  
High Concentration ◽  
Low Concentration ◽  
Start Up ◽  
Anammox Activity

The tremendous input of ammonium and rare earth element (REE) ions released by the enormous consumption of (NH4)2SO4 in in situ leaching for ion-adsorption RE mining caused serious ground and surface water contamination. Anaerobic ammonium oxidation (anammox) was a sustainable in situ technology that can reduce this nitrogen pollution. In this research, in situ, semi in situ, and ex situ method of inoculation that included low-concentration (0.02 mg·L−1) and high-concentration (0.10 mg·L−1) lanthanum (La)(III) were adopted to explore effective start-up strategies for starting up anammox reactors seeded with activated sludge and anammox sludge. The reactors were refrigerated for 30 days at 4 °C to investigate the effects of La(III) during a period of low-temperature. The results showed that the in situ and semi in situ enrichment strategies with the addition of La(III) at a low-concentration La(III) addition (0.02 mg·L−1) reduced the length of time required to reactivate the sludge until it reached a state of stable anammox activity and high nitrogen removal efficiency by 60–71 days. The addition of La(III) promoted the formation of sludge floc with a compact structure that enabled it to resist the adverse effects of low temperature and so to maintain a high abundance of AnAOB and microbacterial community diversity of sludge during refrigeration period. The addition of La(III) at a high concentration caused the cellular percentage of AnAOB to decrease from 54.60 ± 6.19% to 17.35 ± 6.69% during the enrichment and reduced nitrogen removal efficiency to an unrecoverable level to post-refrigeration.

Anammox brings WWTP closer to energy autarky due to increased biogas production and reduced aeration energy for N-removal

2008 ◽  
Vol 57 (3) ◽  
pp. 383-388 ◽  
Author(s):  
H. Siegrist ◽  
D. Salzgeber ◽  
J. Eugster ◽  
A. Joss
Keyword(s):  
Hydraulic Retention Time ◽  
Biogas Production ◽  
Sludge Treatment ◽  
N Removal ◽  
Secondary Sludge ◽  
Organic Carbon Source ◽  
Anammox Process ◽  
Dry Weather Flow ◽  
Heterotrophic Denitrification ◽  
Bod Removal

Fifty years ago when only BOD was removed at municipal WWTPs primary clarifiers were designed with 2–3 hours hydraulic retention time (HRT). This changed with the introduction of nitrogen removal in activated sludge treatment that needed more BOD for denitrification. The HRT of primary clarification was reduced to less than one hour for dry weather flow with the consequence that secondary sludge had to be separately thickened and biogas production was reduced. Only recently the ammonia rich digester liquid (15–20% of the inlet ammonia load) could be treated with the very economic autotrophic nitritation/anammox process requiring half of the aeration energy and no organic carbon source compared to nitrification and heterotrophic denitrification. With the introduction of this new innovative digester liquid treatment the situation reverts, allowing us to increase HRT of the primary clarifier to improve biogas production and reduce aeration energy for BOD removal and nitrification at similar overall N-removal.

Effects of operational parameters on defluoridation efficiency using electrocoagulation process

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
M. Behbahani ◽  
M.R. Alavi Moghaddam ◽  
M. Arami
Keyword(s):  
Reaction Time ◽  
Anode Material ◽  
Removal Efficiency ◽  
Fluoride Concentration ◽  
Fluoride Removal ◽  
Operational Parameters ◽  
Applied Current ◽  
Initial Ph ◽  
Electrocoagulation Process ◽  
Electrode Connection

The aim of this study is to examine the effect of operational parameters on fluoride removal using electrocoagulation method. For this purpose, various operational parameters including initial pH, initial fluoride concentration, applied current, reaction time, electrode connection mode, anode material, electrolyte salt, electrolyte concentration, number of electrodes and interelectrode distance were investigated. The highest defluoridation efficiency achieved at initial pH 6. In the case of initial fluoride concentration, maximum removal efficiency (98.5%) obtained at concentration of 25mg/l. The increase of applied current and reaction time improved defluoridation efficiency up to 99%. The difference of fluoride removal efficiencies between monopolar and bipolar series and monopolar parallel were significant, especially at reaction time of 5 min. When aluminum used as anode material, higher removal efficiency (98.5%) achieved compared to that of iron anode (67.7%). The best electrolyte salt was NaCl with the maximum defluoridation efficiency of 98.5% compared to KNO3 and Na2SO4. The increase of NaCl had no effect on defluoridation efficiency. Number of electrodes had little effect on the amounts of Al3+ ions released in the solution and as a result defluoridation efficiency. Almost the same fluoride removal efficiency obtained for different interelectrode distances.

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