scholarly journals Identifying the Effect of Non-Ideal Mixing on a Pre-Denitrification Activated Sludge System Performance through Model-Based Simulations

2019 ◽  
Vol 2 (1) ◽  
pp. 15-32
Author(s):  
Malek Hajaya
Keyword(s):  
Organic Carbon ◽  
Activated Sludge ◽  
System Performance ◽  
Low Cost ◽  
Dead Volume ◽  
Total Kjeldahl Nitrogen ◽  
Mixing Conditions ◽  
Activated Sludge System ◽  
Ideal Mixing ◽  
Kjeldahl Nitrogen

Effectiveness of a pre-denitrification activated sludge treatment system is governed by the kinetics of the biological reactions, and the hydrodynamic mixing behavior in the reactors. Achieving good mixing conditions within a reactor not only enhances the transfer of reactants but also ensures homogeneous environmental conditions throughout the vessel when required, allowing for an effective usage of the reactor’s total volume, leading to optimized, low-cost operation. In this work, a pre-denitrification activated sludge system performance with regards to the biological treatment of organic carbon and nitrogen was investigated, under two scenarios for non-ideal mixing in the anoxic reactor. The system performance is simulated based upon the Activated Sludge Model 1 model’s biological reactions, and combining two non-ideal mixing two-parameter models: CSTR with bypass and dead volume, and two CSTRs with exchange. Performance discrepancies were then identified in the presence of non-ideal mixing. The system’s performance was found to be more susceptible to the presence of a dead volume/bypass scenario compared to the two CSTRs with material exchange scenario. Under non-ideal mixing conditions, effluent concentrations of Total Kjeldahl Nitrogen, organic carbon increased marginally, while effluent concentration of nitrate increased significantly. Similarly, the waste stream concentrations of Total Kjeldahl Nitrogen and organic carbon increased significantly as a result of an increase in the concentration of the heterotrophic biomass. The outcome of this study provides an insight when troubleshooting the operation of pre-denitrification activated sludge systems for non-ideal mixing conditions.

Parameters for Measuring the Activity and Viability of Activated Sludge

1974 ◽  
Vol 9 (1) ◽  
pp. 235-249 ◽  
Author(s):  
S.G. Nutt ◽  
K.L. Murphy
Keyword(s):  
Organic Carbon ◽  
Activated Sludge ◽  
Biological System ◽  
Analytical Methods ◽  
Heterogeneous System ◽  
Removal Rate ◽  
Bacterial Species ◽  
Atp Content ◽  
Culture Studies ◽  
Activated Sludge System

Abstract Conventional wastewater parameters are accepted as inadequate estimates of the condition of activated sludge but numerous other indices have been suggested as specific measurements of the activity and viability of the biomass. Literature in the related fields of microbiology and biochemistry were reviewed in order to select the most appropriate activity parameters for application to a heterogeneous biological material. Modified analytical methods were applied to a well-controlled biological system containing a single predominant bacterial species to evaluate the relative merit of each as an indicator of viability and activity. The potential of each parameter in a complex heterogeneous system was determined by monitoring each index in a bench activated sludge system. The predominant culture studies indicated that the ATP content of the biomass and the dehydrogenase activity were potential indicators of cell viability in a simple system. However, in the complex activated sludge system, only the ATP content showed significant correlation to the organic carbon removal rate.

Experimental comparison between MBBR and activated sludge system for the treatment of municipal wastewater

2000 ◽  
Vol 41 (4-5) ◽  
pp. 375-382 ◽  
Author(s):  
G. Andreottola ◽  
P. Foladori ◽  
M. Ragazzi ◽  
F. Tatàno
Keyword(s):  
Activated Sludge ◽  
Organic Substance ◽  
Municipal Wastewater ◽  
Low Cost ◽  
Internal Surface ◽  
Experimental Comparison ◽  
Ammonium Removal ◽  
Winter Range ◽  
Activated Sludge System ◽  
Removal Efficiencies

The aim of the described experimentation was the comparison of a low cost MBBR and an activated sludge system (AS). The MBBR applied system consists of the FLOCOR-RMP® plastic media with a specific surface area of about 160 m2/m3 (internal surface only). The comparison with activated sludge (AS) was performed by two parallel treatment lines. Organic substance removal and nitrification were investigated over a 1-year period. Comparing the results obtained with the two lines, it can be observed AS totCOD removal efficiencies were higher than MBBR ones; the average efficiencies for totCOD removal were 76% for MBBR and 84% for AS. On the contrary, the solCOD removals resulted alike (71% for both systems). In spite of the remarkable variations of wastewater temperature, mainly in winter (range of 5–21°C), the average ammonium removal efficiency resulted 92% for MBBR and 98% for AS. With an ammonium loads up to 1.0 g m2 d−1 (up to 0.12 kg m−3 d−1), nitrification efficiencies in MBBR were more than 98%. At higher loads decrease in the MBBR efficiency was registered; that is related to the increase in the applied COD load.

scholarly journals Impact of Effluent from the Leachate Treatment Plant of Taman Beringin Solid Waste Transfer Station on the Quality of Jinjang River

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1553
Author(s):  
Pui Mun Chin ◽  
Aine Nazira Naim ◽  
Fatihah Suja ◽  
Muhammad Fadly Ahmad Usul
Keyword(s):  
Activated Sludge ◽  
Solid Waste ◽  
River Water ◽  
System Performance ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Leachate Treatment ◽  
Activated Sludge System ◽  
Transfer Station ◽  
Waste Transfer

Rapid population growth has contributed to increased solid waste generated in Malaysia. Most landfills that have reached the design capacity are now facing closure. Taman Beringin Landfill was officially closed, so the Taman Beringin Solid Waste Transfer Station was built to manage the relocation, consolidation, and transportation of solid waste to Bukit Tagar Sanitary Landfill. Leachates are generated as a consequence of rainwater percolation through waste and biochemical processes in waste cells. Leachate treatment is needed, as leachates cause environmental pollution and harm human health. This study investigates the impact of treated leachate discharge from a Leachate Treatment Plant (LTP) on the Jinjang River water quality. The performance of the LTP in Taman Beringin Solid Waste Transfer Station was also assessed. Leachate samples were taken at the LTP’s anoxic tank, aeration tank, secondary clarifier tank, and final discharge point, whereas river water samples were taken upstream and downstream of Jinjang River. The untreated leachate returned the following readings: biochemical oxygen demand (BOD) (697.50 ± 127.94 mg/L), chemical oxygen demand (COD) (2419.75 ± 1155.22 mg/L), total suspended solid (TSS) (2710.00 ± 334.79 mg/L), and ammonia (317.08 ± 35.45 mg/L). The LTP’s overall performance was satisfactory, as the final treated leachates were able to meet the standard requirements of the Environmental Quality (Control of Pollution from Solid Waste Transfer Station and Landfill) Regulation 2009. However, the LTP’s activated sludge system performance was not satisfactory, and the parameters did not meet the standard limits. The result shows a low functioning biological treatment method that could not efficiently treat the leachate. However, a subsequent step of combining the biological and chemical process (coagulation, flocculation, activated sludge system, and activated carbon adsorption) helped the treated leachate to meet the standard B requirement stipulated by the Department of Environment (DOE), i.e., to flow safely into the river. This study categorized Jinjang River as polluted, with the discharge of the LTP’s treated leachates, possibly contributing to the river pollution. However, other factors, such as the upstream sewage treatment plant and the ex-landfill downstream, may have also affected the river water quality. The LTP’s activated sludge system performance at the transfer station still requires improvement to reduce the cost of the chemical treatment.

Small sewage treatment system with an anaerobic - anoxic - aerobic combined biofilter

2004 ◽  
Vol 48 (11-12) ◽  
pp. 213-220 ◽  
Author(s):  
S.-M. Park ◽  
H.-B. Jun ◽  
S.-P. Hong ◽  
J.-C. Kwon
Keyword(s):  
Organic Carbon ◽  
Activated Sludge ◽  
Retention Time ◽  
Sewage Treatment ◽  
Treatment System ◽  
Anaerobic Reactor ◽  
Activated Sludge System ◽  
Recycle Ratio ◽  
Removal Efficiencies ◽  
Sewage Treatment System

The objective of this study was to investigate a small sewage treatment system that could improve nitrogen and BOD5 removal efficiency as well as generate less solid using an anaerobic-anoxic-aerobic biofiltration system. Wastewater temperature was in the range of 14–25°C, and hydraulic residual times were 12 h for each reactor. The upflow anaerobic digester equipped with anoxic filter was fed with both raw sewage and recycled effluent from the aerobic filter to induce denitrification and solid reduction simultaneously. In the subsequent aerobic filter, residual organic carbon and ammonia might be oxidized and finally nitrate formed. In the anaerobic reactor, about 71% of influent TCOD was removed by sedimentation of the un-filterable COD at the recycle ratio of 300%. Another 20% of influent TCOD was removed in the anoxic filter by denitrification of the recycled nitrate. After 100 days operation, solid reduction and nitrification efficiency were about 30% and 95%, respectively. Overall removal efficiencies of COD and total nitrogen (T-N) were above 94% and 70% at the recycle ratio of 300%, respectively. Total wasted solid from the system after 100 days operation was about 316 g, which was only 44% of the solid generated from a controlled activated sludge system operated at sludge retention time of 8 days.

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