scholarly journals Performance of electrical stimulated anaerobic baffled reactor for removal of typical pollutants from low-strength municipal wastewater at low temperatures

2019 ◽  
Vol 6 (2) ◽  
pp. 121-128
Author(s):  
Marziye Moradgholi ◽  
Mohamadreza Massoudinejad ◽  
Ehsan Aghayani ◽  
Ahmadreza Yazdanbakhsh

Background: Although anaerobic system has been successfully used for treating the strong industrial wastewater, its efficiency for low-strength wastewater as municipal wastewater is not satisfying. This study aimed to enhance the capability of an anaerobic baffled reactor (ABR) for treating municipal wastewater. Methods: A 7-L ABR with 5 compartments was operated for a 287-day period fed with primary effluent from a wastewater treatment plant at 17 to 19°C. The study was conducted in 2 phases. In the first phase, the performance of ABR and in the second phase, the performance of ESABR (ABR integrated with an electrochemical system) were investigated. Results: The results of ABR operation indicated that at hydraulic retention time (HRT) =24 hours, the average removal efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total Kjeldahl nitrogen (TKN), total phosphorous (TP), and log reduction value (LRV) of coliforms were obtained to be 71%, 75%, 79%, 23%, 30.3%, and 5.8 Log, respectively. In this phase, when the HRT was decreased from 24 to 18 hours and from 18 to 14 hours, the removal efficiency of all parameters by the ABR was decreased. After the shift of ABR operation to ESABR, at HRT=24 hours and current density of 0.78 mA/cm2 , the performance of the reactor was enhanced, so that the removal efficiency of BOD, COD, TSS, TKN, TP, and LRV of coliforms were achieved 16.8%, 15%, 4%, 10.7%, 49%, and 1 Log, which was greater than those obtained by ABR. Conclusion: According to the results, this technology (SEABR) is suitable for treating the low-strength municipal wastewater.

2017 ◽  
Vol 77 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Yanjun Mao ◽  
Xie Quan ◽  
Huimin Zhao ◽  
Yaobin Zhang ◽  
Shuo Chen ◽  
...  

Abstract The activated sludge (AS) process is widely applied in dyestuff wastewater treatment plants (WWTPs); however, the nitrogen removal efficiency is relatively low and the effluent does not meet the indirect discharge standards before being discharged into the industrial park's WWTP. Hence it is necessary to upgrade the WWTP with more advanced technologies. Moving bed biofilm processes with suspended carriers in an aerobic tank are promising methods due to enhanced nitrification and denitrification. Herein, a pilot-scale integrated free-floating biofilm and activated sludge (IFFAS) process was employed to investigate the feasibility of enhancing nitrogen removal efficiency at different hydraulic retention times (HRTs). The results showed that the effluent chemical oxygen demand (COD), ammonium nitrate (NH4+-N) and total nitrogen (TN) concentrations of the IFFAS process were significantly lower than those of the AS process, and could meet the indirect discharge standards. PCR-DGGE and FISH results indicated that more nitrifiers and denitrifiers co-existed in the IFFAS system, promoting simultaneous nitrification and denitrification. Based on the pilot results, the IFFAS process was used to upgrade the full-scale AS process, and the effluent COD, NH4+-N and TN of the IFFAS process were 91–291 mg/L, 10.6–28.7 mg/L and 18.9–48.6 mg/L, stably meeting the indirect discharge standards and demonstrating the advantages of IFFAS in dyestuff wastewater treatment.


2011 ◽  
Vol 1 (3) ◽  
pp. 179-184 ◽  
Author(s):  
Beenish Saba ◽  
Tariq Mahmood ◽  
Bushra Zaman ◽  
Imran Hashmi

Reclaimed wastewater reuse for irrigation to crop plants is evaluated in a laboratory-scale experiment to assess growth and water saving potential from natural resources. A prototype laboratory-scale treatment plant was established for this purpose with suspended and attached growth configurations. Chakwal wheat variety was selected to examine growth parameters. The removal of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were evaluated to check the quality of treated water. It was found that a suspended growth sequencing batch bioreactor (SGSBBR) achieved 97% ± 2 removal efficiency over a 4 h hydraulic retention time (HRT). For an attached growth sequencing batch bioreactor (AGSBBR) results showed 98% ± 2 removal efficiencies with polyurethane. TN and TP removal efficiency was 58.7 ± 3% and 64 ± 4.8% in SGSBBR, 53 ± 0.17% and 67 ± 2.7% in polyurethane. AGSBBR enhanced performance with AGSBBR may be due to enforced anoxic/aerobic conditions in the inner layers of biofilm formed on biocarriers which facilitate the required metabolic conditions for treating high strength wastewater. Plant growth was visibly greater in SGSBBR treated wastewater than AGSBBR because of less nutrient removal.


2018 ◽  
Vol 78 (9) ◽  
pp. 1843-1851 ◽  
Author(s):  
İ. Çelen-Erdem ◽  
E. S. Kurt ◽  
B. Bozçelik ◽  
B. Çallı

Abstract The sludge digester effluent taken from a full scale municipal wastewater treatment plant (WWTP) in Istanbul, Turkey, was successfully deammonified using a laboratory scale two-stage partial nitritation (PN)/Anammox (A) process and a maximum nitrogen removal rate of 1.02 kg N/m3/d was achieved. In the PN reactor, 56.8 ± 4% of the influent NH4-N was oxidized to NO2-N and the effluent nitrate concentration was kept below 1 mg/L with 0.5–0.7 mg/L of dissolved oxygen and pH of 7.12 ± 12 at 24 ± 4°C. The effluent of the PN reactor was fed to an upflow packed bed Anammox reactor where high removal efficiency was achieved with NO2-N:NH4-N and NO3-N:NH4-N ratios of 1.32 ± 0.19:1 and 0.22 ± 0.10:1, respectively. The results show that NH4-N removal efficiency up to 98.7 ± 2.4% and total nitrogen removal of 87.7 ± 6.5% were achieved.


2019 ◽  
Vol 80 (9) ◽  
pp. 1654-1661
Author(s):  
J. Tauber ◽  
V. Parravicini ◽  
K. Svardal ◽  
J. Krampe

Abstract In this research, sources of methane emissions of an anaerobic digester (AD) system at a municipal wastewater treatment plant (WWTP) with 260,000 population equivalent (PE) capacity were detected by a non-dispersive infrared (NDIR) camera. The located emissions were evaluated qualitatively and were documented with photographs and video films. Subsequently, the emission sources were quantified individually using different methods like the Flux-Chamber method and sampling from the digester's circulation pipe. The dissolved methane in the sludge digester was measured via gas chromatography-mass spectrometry (GC-MS) and 6.8% oversaturation compared to the equilibrium after Henry's law was found. Additionally, the residual gas potential of the digestate was measured using batch tests with 10 days' additional stabilisation time. The PE-specific residual gas production of the full-scale AD was calculated to 12.4 g CH4/(PE · y). An extended chemical oxygen demand (COD) balance including methane emissions for the whole digester system was calculated. Also the measured methane loads were calculated and summed up. The total methane loss of the AD was calculated at 24.6 g CH4/(PE · y), which corresponds to 0.4% of the produced biogas (4,913 g CH4/(PE · y)). PE-specific methane emission factors are presented for each investigated (point) source like the sludge outlet at the digester's head, a leaking manhole sealing and cracks in the concrete structure.


2018 ◽  
Vol 78 (9) ◽  
pp. 1879-1892 ◽  
Author(s):  
Md Khalekuzzaman ◽  
Muhammed Alamgir ◽  
Mehedi Hasan ◽  
Md Nahid Hasan

Abstract In this research, a hybrid anaerobic baffled reactor (HABR) configuration was proposed consisting of a front sedimentation chamber and four regular baffled chambers followed by two floated filter media chambers for the treatment of domestic wastewater. Performance comparison of uninsulated and insulated HABRs was carried out operating at warm temperature (18.6–37.6 °C) under variable HRTs (30 h and 20 h). The study suggests that almost similar chemical oxygen demand (91% vs 88%), total suspended solids (90% vs 95%), turbidity (98% vs 97%), and volatile suspended solids (90% vs 93%) removal efficiencies were obtained for uninsulated and insulated HABRs. Higher removal of total nitrogen (TN) of 41%, NH4+-N of 44%, and NO3−-N of 91% were achieved by the insulated HABR compared to TN of 37%, NH4+-N of 36%, and NO3−-N of 84% by the uninsulated HABR, whereas lower PO43− removal efficiency of 17% was found in the insulated HABR compared to 24% in the uninsulated HABR. This indicated insulation increased nitrogen removal efficiencies by 4% for TN, 8% for NH4+-N and 7% for NO3−-N, but decreased PO43−removal efficiency by 7%.


2018 ◽  
Vol 78 (11) ◽  
pp. 2288-2296 ◽  
Author(s):  
Hongying Xu ◽  
Ru Jin ◽  
Chan Zhang ◽  
Yupeng Wu ◽  
Xiaohui Wang

Abstract Excessive emission of plant nutrients (such as nitrogen and phosphorus) into the water body can induce eutrophication. Therefore, how to control eutrophic water efficiently and economically is very important. In the paper, highly efficient aerobic denitrifying phosphorus removing J16 bacteria was isolated from the activated sludge of an aerobic bioreactor in Taiyuan municipal wastewater treatment plant by using the blue–white spot screening method, an aerobic phosphorus absorption test, nitrate reduction test, nitrogen removal experiments, and plate coating and streaking methods. Through 16S rDNA gene homology comparison and physiological and biochemical identification, the J16 strain was preliminarily identified as Escherichia coli, with a sequence similarity of 99%. The 16S rDNA sequence of strain J16 was submitted to GenBank (accession number: MF667015). The effect of temperature, pH, percentage of inoculum and phosphate-P (PO43−-P) concentration on denitrification and phosphorus removal efficiency was investigated through a single-factor experiment. The optimum conditions of the J16 strain for denitrification and phosphorus removal were as follows: 30°C, neutral or weak alkaline (pH: 7.2–8), and 3% of inoculum, respectively. The denitrification and phosphorus removal efficiency of strain J16 was the highest when PO43−-P and nitrate-N(NO3−-N) concentrations were 8.9 and 69.31 mg/L, and the removal were 96.03% and 94.55%, respectively. In addition, strain J16 could reduce phosphoric acid to phosphine (PH3) and remove some phosphorus under hypoxia conditions. This is the first study to report the involvement of Escherichia coli in nitrogen and phosphorus removal under aerobic and hypoxia conditions. Based on the above results, the strain J16 can effectively remove nitrogen and phosphorus, and will be utilized in enhancing treatment of nitrogen and phosphorus-containing industrial wastewater and phosphorus reclamation.


2013 ◽  
Vol 807-809 ◽  
pp. 694-698
Author(s):  
Rong Xin Huang ◽  
Zhen Xing Wang ◽  
Gang Liu ◽  
Qi Jin Luo

In order to guarantee the reliability and security of reclaiming water, research on the removal efficiency of the environmental endocrine chemicals (EDCs) --the Phthalate Esters (PAEs) in conventional secondary activated sludge and wastewater reclamation and reuse process was undergoing at Harbin wastewater treatment plant (WWTP). The wastewater samples were colleted from every unit effluent of WWTP. The results showed that contamination of EDCs were presented in municipal wastewater at Harbin and the concentrations of the four PAEs were 21.01μg/L for Di-n-butyl Phthalate (DBP); 9.63μg/L for Di-n-octyl Phthalate (DnOP); 4.56μg/L for Diethyl Phthalate (DEP); 1.96μg/L for Dimethyl Phthalate (DMP) respectively in the influent. The conventional activated sludge has good removal efficiencies performance on DMP, DEP and DBP. With the increasing of molecular weight and branch chains of PAEs contaminations, the removal rate of the four PAEs in the conventional activated sludge process decreased from 99.82%(DMP),90.60%(DEP),90.10%(DBP) to the only 45.13% removal rate for DnOP, which was mostly removed from primary treatment but no from secondary activated sludge process; Coagulation-air flotation plus filtration process was not a feasible way to remove PAEs from reclaiming treatment units.


2013 ◽  
Vol 20 (1) ◽  
pp. 199-208 ◽  
Author(s):  
Marketa Julinova ◽  
Jan Kupec ◽  
Roman Slavik ◽  
Maria Vaskova

Abstract A synthetic polymer, polyvinylpyrrolidone (PVP - E 1201) primarily finds applications in the pharmaceutical and food industries due to its resistance and zero toxicity to organisms. After ingestion, the substance passes through the organism unchanged. Consequently, it enters the systems of municipal wastewater treatment plants (WWTP) without decomposing biologically during the waste treatment process, nor does it attach (through sorption) to particles of activated sludge to any significant extent, therefore, it passes through the system of a WWTP, which may cause the substance to accumulate in the natural environment. For this reason the paper investigates the potential to initiate aerobic biodegradation of PVP in the presence of activated sludge from a municipal wastewater treatment plant. The following agents were selected as the initiators of the biodegradation process - co-substrates: acrylamide, N-acethylphenylalanine and 1-methyl-2-pyrrolidone, a substance with a similar structure to PVP monomer. The biodegradability of PVP in the presence of co-substrates was evaluated on the basis of biological oxygen demand (BOD) as determined via a MicroOxymax O2/CO2/CH4 respirometer. The total substrate concentration in the suspension equaled 400 mg·dm-3, with the ratio between PVP and the cosubstrate being 1:1, while the concentration of the dry activated sludge was 500 mg·dm-3. Even though there was no occurrence of a significant increase in the biodegradation of PVP alone in the presence of a co-substrate, acrylamide appeared to be the most effective type of co-substrate. Nevertheless, a recorded decrease in the slope of biodegradation curves over time may indicate that a process of primary decomposition was underway, which involves the production of metabolites that inhibit activated sludge microorganisms. The resulting products are not identified at this stage of experimentation.


2018 ◽  
Vol 77 (11) ◽  
pp. 2723-2732 ◽  
Author(s):  
Xiaowei Zheng ◽  
Shenyao Zhang ◽  
Jibiao Zhang ◽  
Deying Huang ◽  
Zheng Zheng

Abstract With the improvement of wastewater discharge standards, wastewater treatment plants (WWTPs) are continually undergoing technological improvements to meet the evolving standards. In this study, a quartz sand deep bed denitrification filter (DBDF) was used to purify WWTP secondary effluent, utilizing high nitrate nitrogen concentrations and a low C/N ratio. Results show that more than 90% of nitrate nitrogen (NO3-N) and 75% of chemical oxygen demand (COD) could be removed by the 20th day of filtration. When the filter layer depth was set to 1,600 mm and the additional carbon source CH3OH was maintained at 30 mg L−1 COD (20 mg L−1 methanol), the total nitrogen (TN) and COD concentrations of DBDF effluent were stabilized below 5 and 30 mg L−1, respectively. Analysis of fluorescence revealed that DBDF had a stronger effect on the removal of dissolved organic matter (DOM), especially of aromatic protein-like substances. High throughput sequencing and qPCR results indicate a distinctly stratified microbial distribution for the main functional species in DBDF, with quartz sand providing a good environment for microbes. The phyla Proteobacteria, Bacteroidetes, and Chloroflexi were found to be the dominant species in DBDF.


2013 ◽  
Vol 68 (1) ◽  
pp. 117-123 ◽  
Author(s):  
M. K. Pandey ◽  
P. D. Jenssen ◽  
T. Krogstad ◽  
Sven Jonasson

In the search for design criteria for constructed wetlands (CWs) in Nepal a semi-scale experimental setup including horizontal flow (HF) and vertical flow (VF) CWs was developed. This paper compares the performance of HF and VF wetlands, and planted with unplanted beds. The experimental setup consists of two units of HF and VF beds of size 6 m × 2 m × 0.6 m and 6 m × 2 m × 0.8 m (length × width × depth) respectively. For both HF and VF systems, one unit was planted with Phragmites karka (local reed) and one was not planted. The systems were fed with wastewater drawn from the grit chamber of a municipal wastewater treatment plant. The media consisted of river gravel. In the first phase of the experiment the hydraulic loading rate (HLR) was varied in steps; 0.2, 0.08, 0.04 m3/m2/d and the percent removal increase with decrease in HLR for all beds and parameters except for total phosphorus. In the second phase the loading rate of 0.04 m3/m2/d was run for 7 months. In both parts of the experiment the planted beds performed better than the unplanted beds and the VF better than the HF beds. To meet Nepalese discharge standards HF beds are sufficient, but to meet stricter requirements a combination of HF and VF beds are recommended.


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