Pre-nitrification by encapsulated nitrifiers - a possibility for self-sufficient energy operation of domestic WWTPs

2003 ◽  
Vol 47 (11) ◽  
pp. 173-180
Author(s):  
M. Sievers ◽  
K.D. Vorlop ◽  
J. Hahne ◽  
M. Schlieker ◽  
S. Schäfer
Keyword(s):  
Energy Consumption ◽  
Oxygen Demand ◽  
High Energy ◽  
Anaerobic Sludge ◽  
Nitrification Rate ◽  
Treatment Efficiency ◽  
Nitrogen And Phosphorus ◽  
Operational Conditions ◽  
Sufficient Energy ◽  
New Process

The overall energy consumption of domestic wastewater treatment plants (WWTPs) increases with treatment efficiency. Approximately 30 to 45 kWh per people equivalent and year is mostly necessary for advanced nitrogen and phosphorus removal, while the aeration contains the main part of approximately 60%. A new process using encapsulated nitrifiers on gel lens beads is introduced to overcome the high energy consumption of aeration. A more selective nitrification process was found at a nitrification rate of between 50 and 60 mg nitrogen per hour and litre reaction volume corresponding to a hydraulic retention time (HRT) of about 30 to 60 minutes while the soluble Chemical Oxygen Demand (COD) removal could be less than 30% depending on operational conditions of the bio-reactor. The latter enables internal use of wastewater's COD for a post denitrification. For the new process the energy consumption as well as total volume of bio-reactor are much less (approximately 30 to 50% for both) than conventional processes due to the low sludge age for COD and nitrate removal and the avoidance of internal wastewater recycle. Therefore, self-sufficient energy operation of domestic WWTPs operating with advanced treatment efficiency could become possible, if energy recovery by anaerobic sludge digestion is included.

scholarly journals Operational modifications for the development of nitrifying bacteria in a large-scale biological aerated filter and its impact on wastewater treatment

2018 ◽  
Vol 78 (8) ◽  
pp. 1704-1714 ◽  
Author(s):  
François-René Bourgeois ◽  
Frédéric Monette ◽  
Daniel G. Cyr
Keyword(s):  
Large Scale ◽  
Oxygen Demand ◽  
Bacterial Biofilm ◽  
Nitrifying Bacteria ◽  
Nitrification Rate ◽  
Total Biomass ◽  
Ammonia Oxidizing Bacteria ◽  
Operational Conditions ◽  
Nitrite Oxidizing Bacteria ◽  
Aerated Filter

Abstract To develop a better understanding for fixed biomass processes, the development of a nitrifying bacterial biofilm, as well as the performance of treatment during modifications to operational conditions of a full-scale submerged biological filter were examined. The development of the nitrifying biofilm was investigated at four depth levels (1, 2, 4 and 5 feet). The result of bacterial subpopulations analyzed by qPCR relative to the physico-chemical parameters of the wastewater during the various tests (sustained aeration, modified backwash parameters and inflow restriction) revealed an increase of the relative presence of nitrifying microorganisms throughout the biofilm (especially for nitrite oxidizing bacteria (NOB)), but this was not necessarily accompanied by a better nitrification rate. The highest observed nitrification rate was 49% of removal in the test cell during backwashing conditions, whereas the relative ammonia oxidizing bacteria (AOB) population was 0.032% and NOB was 0.008% of the total biomass collected. The highest percentage of nitrifying bacteria observed (0.034% AOB and 0.18% NOB) resulted in a nitrification rate of 21%. The treatment of organic matter determined by measuring the chemical and biochemical oxygen demand (COD, CBOD5) was improved.

scholarly journals Benchmarking of energy consumption in municipal wastewater treatment plants – a survey of over 200 plants in Italy

2018 ◽  
Vol 77 (9) ◽  
pp. 2242-2252 ◽  
Author(s):  
M. Vaccari ◽  
P. Foladori ◽  
S. Nembrini ◽  
F. Vitali
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Municipal Wastewater ◽  
Energy Savings ◽  
Wastewater Treatment Plants ◽  
Specific Energy Consumption ◽  
Oxygen Demand ◽  
Energy Performance ◽  
High Energy ◽  
Municipal Wastewater Treatment

Abstract One of the largest surveys in Europe about energy consumption in Italian wastewater treatment plants (WWTPs) is presented, based on 241 WWTPs and a total population equivalent (PE) of more than 9,000,000 PE. The study contributes towards standardised resilient data and benchmarking and to identify potentials for energy savings. In the energy benchmark, three indicators were used: specific energy consumption expressed per population equivalents (kWh PE−1 year−1), per cubic meter (kWh/m3), and per unit of chemical oxygen demand (COD) removed (kWh/kgCOD). The indicator kWh/m3, even though widely applied, resulted in a biased benchmark, because highly influenced by stormwater and infiltrations. Plants with combined networks (often used in Europe) showed an apparent better energy performance. Conversely, the indicator kWh PE−1 year−1 resulted in a more meaningful definition of a benchmark. High energy efficiency was associated with: (i) large capacity of the plant, (ii) higher COD concentration in wastewater, (iii) separate sewer systems, (iv) capacity utilisation over 80%, and (v) high organic loads, but without overloading. The 25th percentile was proposed as a benchmark for four size classes: 23 kWh PE−1 y−1 for large plants > 100,000 PE; 42 kWh PE−1 y−1 for capacity 10,000 < PE < 100,000, 48 kWh PE−1 y−1 for capacity 2,000 < PE < 10,000 and 76 kWh PE−1 y−1 for small plants < 2,000 PE.

scholarly journals Process Intensification and its Applications - A Critical Review

2020 ◽  
Vol 13 (4) ◽  
pp. 402-412
Author(s):  
Sarthak Vaidya ◽  
Haribalakrishnammal Vaidyanathan ◽  
Sonali R Dhokpande
Keyword(s):  
Energy Consumption ◽  
Residence Time ◽  
Industrial Waste ◽  
Process Intensification ◽  
High Energy ◽  
Alternative Pathways ◽  
New Process ◽  
Micro Reactors ◽  
The Cost ◽  
High Energy Consumption

The problems faced by the various industries are high energy consumption which further increases the cost of production followed by reduced productivity and conversion, longer residence time, and pollution caused by industrial waste. Many researchers have found various alternative pathways to overcome these drawbacks. The same products were obtained in a better way by process intensification. Any process can be intensified either by introducing entirely a new process or by combing two or more conventional methods to form a new hybrid process e.greactive distillation, micro-reactors, etc. Due to an increase in population and less availability of land, reducing the chemical plant footprints is highly appreciable which is possible by process intensification. In this paper, we have reviewed the majority of the processes that have been intensified into a new process such as bioprocesses, extraction, distillation, leaching, Biofuels production, Desalination, etc.

scholarly journals An A2O-MBR system for simultaneous biological nitrogen and phosphorus removal from brewery wastewater at various nitrate recirculation ratios

2021 ◽  
Vol 258 ◽  
pp. 08011
Author(s):  
Van Nu Thai Thien ◽  
Dang Viet Hung ◽  
Nguyen Thi Thanh Hoa ◽  
Thi Ha Nguyen ◽  
Phan Thanh Trong
Keyword(s):  
Industrial Wastewater ◽  
Oxygen Demand ◽  
Organic Loading Rate ◽  
Brewery Wastewater ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Operational Conditions ◽  
Solids Retention ◽  
Removal Efficiencies ◽  
Biological Nitrogen

Anaerobic/Anoxic/Oxic – Membrane BioReactor (A2O-MBR) system including A2O unit at short solids retention time (SRT) for accumulation of PO43--P and MBR at long SRT for nitrification of NH4+-N was used to enhance simultaneous removal of nitrogen and phosphorus from brewery wastewater. The model of A2O-MBR system made from polyacrylic with the capacity of 49.5 liters was operated with organic loading rate of 0.75 kgCOD/m3.day. Nitrate recycling ratio was increased from 100 to 300% while sludge recirculation ratio was maintained at 100%. The results showed that for the nitrate recycling ratios of 100, 200, 300%, average NH4+-N and total nitrogen (TN) removal efficiencies of the model were 95.7 and 72.4, 99.2 and 86.7, 99.3 and 89.6%, respectively. The removal efficiencies of chemical oxygen demand (COD) and total phosphorus (TP) were over 90 and 75%, respectively, regardless of nitrate recirculation ratio. The output values of COD, NH4+-N, TN and TP were within the limits of Vietnam National Technical Regulation on Industrial Wastewater (QCVN 40:2011/BTNMT), column A, throughout the experiments. The model with recommended system configuration and optimum operational conditions could treat not only nitrogen but also phosphorus well due to appropriate nitrate recycling ratios.

Nitrogen removal from high organic loading wastewater in modified Ludzack–Ettinger configuration MBBR system

2015 ◽  
Vol 72 (8) ◽  
pp. 1274-1282 ◽  
Author(s):  
Mojtaba Torkaman ◽  
Seyed Mehdi Borghei ◽  
Sepehr Tahmasebian ◽  
Mohammad Reza Andalibi
Keyword(s):  
Loading Rate ◽  
Oxygen Demand ◽  
Biofilm Reactor ◽  
Denitrification Rate ◽  
Synthetic Wastewater ◽  
Organic Loading Rate ◽  
Nitrification Rate ◽  
Organic Loading ◽  
Operational Conditions ◽  
Aerobic Reactor

A moving bed biofilm reactor with pre-denitrification configuration was fed with a synthetic wastewater containing high chemical oxygen demand (COD) and ammonia. By changing different variables including ammonium and COD loading, nitrification rate in the aerobic reactor and denitrification rate in the anoxic reactor were monitored. Changing the influent loading was achieved via adjusting the inlet COD (956–2,096 mg/L), inlet ammonium (183–438 mg/L), and hydraulic retention time of the aerobic reactor (8, 12, and 18 hours). The overall organic loading rate was in the range of 3.60–17.37 gCOD/m2·day, of which 18.5–91% was removed in the anoxic reactor depending on the operational conditions. Considering the complementary role of the aerobic reactor, the overall COD removal was in the range 87.3–98.8%. In addition, nitrification rate increased with influent ammonium loading, the maximum rate reaching 3.05 gNH4/m2·day. One of the most important factors affecting nitrification rate was influent C:N entering the aerobic reactor, by increasing which nitrification rate decreased asymptotically. Nitrate removal efficiency in the anoxic reactor was also controlled by the inlet nitrate level entering the anoxic reactor. Furthermore, by increasing the nitrate loading rate from 0.91 to 3.49 gNO/m3·day, denitrification rate increased from 0.496 to 2.47 gNO/m3·day.

Diversity and dynamics of ammonia-oxidizing bacterial communities in a sponge-based trickling filter treating effluent from a UASB reactor

2013 ◽  
Vol 68 (3) ◽  
pp. 650-657 ◽  
Author(s):  
E. F. A. Mac Conell ◽  
P. G. S. Almeida ◽  
A. M. Zerbini ◽  
E. M. F. Brandt ◽  
J. C. Araújo ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Oxygen Demand ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Trickling Filter ◽  
Strong Concentration ◽  
Operational Conditions ◽  
N Removal

Changes in ammonia-oxidizing bacterial (AOB) population dynamics were examined in a new sponge-based trickling filter (TF) post-upflow anaerobic sludge blanket (UASB) reactor by denaturating gradient gel electrophoresis (DGGE), and these changes were linked to relevant components influencing nitrification (chemical oxygen demand (COD), nitrogen (N)). The sponge-based packing media caused strong concentration gradients along the TF, providing an ecological selection of AOB within the system. The organic loading rate (OLR) affected the population dynamics, and under higher OLR or low ammonium-nitrogen (NH4+-N) concentrations some AOB bands disappeared, but maintaining the overall community function for NH4+-N removal. The dominant bands present in the upper portions of the TF were closely related to Nitrosomonas europaea and distantly affiliated to Nitrosomonas eutropha, and thus were adapted to higher NH4+-N and organic matter concentrations. In the lower portions of the TF, the dominant bands were related to Nitrosomonas oligotropha, commonly found in environments with low levels of NH4+-N. From a technology point of view, changes in AOB structure at OLR around 0.40–0.60 kgCOD m−3 d−1 did not affect TF performance for NH4+-N removal, but AOB diversity may have been correlated with the noticeable stability of the sponge-based TF for NH4+-N removal at low OLR. This study is relevant because molecular biology was used to observe important features of a bioreactor, considering realistic operational conditions applied to UASB/sponge-based TF systems.

Enhanced removal of chemical oxygen demand, nitrogen and phosphorus using the ameliorative anoxic/anaerobic/oxic process and micro-electrolysis

2012 ◽  
Vol 66 (4) ◽  
pp. 850-857 ◽  
Author(s):  
K. Q. Bao ◽  
J. Q. Gao ◽  
Z. B. Wang ◽  
R. Q. Zhang ◽  
Z. Y. Zhang ◽  
...  
Keyword(s):  
Chemical Oxygen Demand ◽  
Hydraulic Retention Time ◽  
Loading Rate ◽  
Oxygen Demand ◽  
Synthetic Wastewater ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Nitrogen And Phosphorus ◽  
Operational Conditions ◽  
Removal Efficiencies

Synthetic wastewater was treated using a novel system integrating the reversed anoxic/anaerobic/oxic (RAAO) process, a micro-electrolysis (ME) bed and complex biological media. The system showed superior chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) removal rates. Performance of the system was optimised by considering the influences of three major controlling factors, namely, hydraulic retention time (HRT), organic loading rate (OLR) and mixed liquor recirculation (MLR). TP removal efficiencies were 69, 87, 87 and 83% under the HRTs of 4, 8, 12 and 16 h. In contrast, HRT had negligible effects on the COD and TN removal efficiencies. COD, TN and TP removal efficiencies from synthetic wastewater were 95, 63 and 87%, respectively, at an OLR of 1.9 g/(L·d). The concentrations of COD, TN and TP in the effluent were less than 50, 15 and 1 mg/L, respectively, at the controlled MLR range of 75–100%. In this system, organics, TN and TP were primarily removed from anoxic tank regardless of the operational conditions.

Dissolved oxygen, COD, nitrogen and phosphorus profiles in a continuous sand filter used for WWTP effluent reclamation

2012 ◽  
Vol 66 (7) ◽  
pp. 1511-1518 ◽  
Author(s):  
Hongbin Xu ◽  
Sigrid M. Scherrenberg ◽  
Jules B. van Lier
Keyword(s):  
Dissolved Oxygen ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Total Removal ◽  
Nitrogen And Phosphorus ◽  
Operational Conditions ◽  
European Water ◽  
Wwtp Effluent ◽  
Filter Bed ◽  
The Given

Continuous sand filtration (CSF) offers interesting potential for the extensive treatment of wastewater treatment plant (WWTP) effluents for water reclamation and/or restrictive discharge. Research on concentration profiles over the height of the CSF shows that most bacteriological conversions are restricted to the lower part of the filter bed. Dissolved oxygen (DO) rapidly decreases to below 1 mg/L in the first 0.4 m of the filter bed, applying hydraulic velocities of 12.9 ∼ 14.9 m/h and 10 ∼ 20 mm/min sand velocities, independent of the methanol dosage. The DO decrease agrees with the observed decrease in chemical oxygen demand (COD). At the given operational conditions, NOx-N and N-total removal is dedicated to the first 0.9 m of the filter bed. Results show that by optimising the CSF operational conditions the very restrictive effluent N and P values of 2.2 and 0.15 mg/L, respectively, as described in the European Water Framework Directive, can be met.

Advanced biological enhanced nutrient removal processes by the addition of rotating biological contactors

1997 ◽  
Vol 35 (8) ◽  
pp. 153-160 ◽  
Author(s):  
Jau-Lang Su ◽  
Chaio-Fuei Ouyang
Keyword(s):  
Organic Carbon ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Municipal Wastewater ◽  
Nitrification Rate ◽  
Nitrogen And Phosphorus ◽  
Solid Retention Time ◽  
Recycle Ratio ◽  
New Process ◽  
Rotating Biological Contactors

Advanced removal efficiency of organic carbon, phosphorus and nitrogen from municipal wastewater was achieved by using an anaerobic-anoxic-oxide (A2/O) process with the addition of fully and partially submerged RBC biofilms. The experiments were carried out in a range of F/M ratio 0.21 to 0.32 kg BOD/kg MLSS/d and at a various total hydraulic detention times (HRT), return activated sludge ratio (r) and mixed liquid recycle ratio (R). Another pilot plant A2/O process without adding RBC was conducted for control experiments. Compared with A2/O process, this new process could achieve a higher degree of nitrification rate without decreasing the removal efficiencies of organic carbon and phosphorus. The new process provides an environment for combining the long solid retention time (SRT) biofilm and the short SRT suspended activated sludge. This concept can resolve the conflict in SRT between nitrogen and phosphorus removal simultaneously. Correspondingly, the benefits of the new process are shorten the hydraulic detention time, progress the efficiency of nutrient removal, more stable for operation and more economic for required land cost.

Sequential anaerobic/aerobic biotreatment of bark leachate

2003 ◽  
Vol 48 (6) ◽  
pp. 203-209 ◽  
Author(s):  
J.C. Frigon ◽  
R. Cimpoia ◽  
S.R. Guiot
Keyword(s):  
Oxygen Demand ◽  
Anaerobic Treatment ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Phenol Removal ◽  
Aerobic Treatment ◽  
Hydraulic Residence Time ◽  
Operational Conditions ◽  
Fixed Film ◽  
Air Diffusion

Bark leachate is generated from sawmill operations such as log storage sites and contains polymeric tannins, carbohydrates, organic acids, phenolic and resin compounds. The present study was aimed at assessing the performance of a sequential anaerobic and aerobic treatment, for both chemical oxygen demand (COD) and phenol removal, under various combinations of operational conditions, in the continuous mode. After anaerobic treatment in a five litres upflow anaerobic sludge bed (UASB) reactor, the leachate was directed into two parallel aerobic reactors, either an activated sludge unit or a fixed film submerged filter (packed with polyethylene Flexirings), both of a volume of one litre and oxygenated by air diffusion. For a leachate of 22 gCOD/l, an overall COD removal of 96Ð98% was achieved at an hydraulic residence time (HRT) of 4 days for the anaerobic reactor and one day for either aerobic systems. The phenol concentration generally increased after anaerobic treatment but was below the detection limit (50 ppb) after aerobic polishing. Radiorespirometric microcosms with 14C-labelled phenol confirmed that phenol was mineralized in the aerobic reactors. The performances of both aerobic systems were similar for COD and phenol removal. Thus, a sequential anaerobic/aerobic treatment was able to effectively address the contamination of a bark leachate discharge, including phenols.

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