Sludge accumulation pattern inside oxidation ditch case study

2014 ◽  
Vol 69 (12) ◽  
pp. 2468-2475 ◽  
Author(s):  
Moharram Fouad ◽  
Ahmed El-Morsy
Keyword(s):  
Suspended Solids ◽  
Municipal Wastewater ◽  
Weather Conditions ◽  
System Failure ◽  
Oxidation Ditch ◽  
Accumulation Pattern ◽  
Mixed Liquor ◽  
Economical Design ◽  
Sludge Accumulation

The sludge accumulation pattern of an oxidation ditch (OD) plant treating municipal wastewater was observed under dry and wet weather conditions, during 3 years of operation. The accumulation patterns along the ditches and their rates were revealed. In addition, the composition of the accumulation was investigated. Finally, the ratio of sand and volatile particles, mixed liquor suspended solids (MLSS), and mixed liquor volatile suspended solids, as well as the removal efficiency were also observed against the accumulated sludge. Further, a laboratory-scale channel was used to investigate the settleability of grit after mixing with variable values of MLSS. The observed results indicated that the economical design and operation of ODs using a velocity value between 0.3–0.35 m/s is not recommended, to avoid the settling of all solids. High values of MLSS and sludge age need high horizontal velocity (more than 0.35 m/s) and more power to avoid settling problems and system failure. The influence of flow velocity on the sludge settleability was studied, enabling better planning of future ditch design and operation.

scholarly journals Co-treatment of old landfill leachate and municipal wastewater in sequencing batch reactor (SBR): effect of landfill leachate concentration

2016 ◽  
Vol 51 (4) ◽  
pp. 377-387 ◽  
Author(s):  
Kshitij Ranjan ◽  
Shubhrasekhar Chakraborty ◽  
Mohini Verma ◽  
Jawed Iqbal ◽  
R. Naresh Kumar
Keyword(s):  
Removal Efficiency ◽  
Landfill Leachate ◽  
Suspended Solids ◽  
Sequencing Batch Reactor ◽  
Municipal Wastewater ◽  
Batch Reactor ◽  
Operating Conditions ◽  
Volume Index ◽  
Turbidity Removal ◽  
Mixed Liquor

Sequencing batch reactor (SBR) was assessed for direct co-treatment of old landfill leachate and municipal wastewater for chemical oxygen demand (COD), nutrients and turbidity removal. Nitrogen removal was achieved by sequential nitrification and denitrification under post-anoxic conditions. Initially, SBR operating conditions were optimized by varying hydraulic retention time (HRT) at 20% (v/v) landfill leachate concentration, and results showed that 6 d HRT was suitable for co-treatment. SBR performance was assessed in terms of COD, ammonia, nitrate, phosphate, and turbidity removal efficiency. pH, mixed liquor suspended solids, mixed liquor volatile suspended solids (MLVSS), and sludge volume index were monitored to evaluate stability of SBR. MLVSS indicated that biomass was able to grow even at higher concentrations of old landfill leachate. Ammonia and nitrate removal efficiency was more than 93% and 83%, respectively, whereas COD reduction was in the range of 60–70%. Phosphate and turbidity removal efficiency was 80% and 83%, respectively. Microbial growth kinetic parameters indicated that there was no inhibition of biomass growth up to 20% landfill leachate. The results highlighted that SBR can be used as an initial step for direct co-treatment of landfill leachate and municipal wastewater.

Analyzing wet weather flow management using state of the art tools

2008 ◽  
Vol 57 (8) ◽  
pp. 1247-1251 ◽  
Author(s):  
Denny S. Parker ◽  
Rion P. Merlo ◽  
Jose A. Jimenez ◽  
Eric J. Wahlberg
Keyword(s):  
Suspended Solids ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
State Of The Art ◽  
Fluid Dynamic ◽  
Municipal Wastewater Treatment ◽  
Secondary Clarifier ◽  
Wet Weather ◽  
Municipal Wastewater Treatment Plants

Optimal secondary clarifier performance is crucial to meet treatment requirements, especially when treating peak wet weather flows (PWWFs), to prevent high effluent suspended solids (ESS) concentrations and elevated sludge blankets. A state-of-the-art computational fluid dynamic (CFD) model was successfully used as a design and diagnostic tool to optimize performance for municipal wastewater treatment plants subject to significant PWWFs. Two case studies are presented. For Case Study 1, the model was used to determine the number of secondary clarifiers that will be necessary to treat future PWWF conditions for a plant under design. For Case Study 2, the model was used to identify modifications that are currently being made to increase the clarifier capacity for handling PWWF.

scholarly journals Impact assessment wastewater discharge on water quality DTD canal Becej-Bogojevo

2015 ◽  
Vol 69 (3) ◽  
pp. 219-229 ◽  
Author(s):  
Vesna Pesic ◽  
Milena Becelic-Tomin ◽  
Bozo Dalmacija ◽  
Dejan Krcmar
Keyword(s):  
Water Quality ◽  
River Basin ◽  
Suspended Solids ◽  
Impact Analysis ◽  
Municipal Wastewater ◽  
Human Impacts ◽  
Weather Conditions ◽  
River Basin Management ◽  
Good Potential ◽  
The Impact

Pressure and impact analysis requires information on the main drivers and changes in conditions. In order to analyze such pressures and impacts, each river basin requires: an analysis of its characteristics, a review of the impact of human activity on the status of the surface water and an economic analysis of water use. Pressure and impact analysis plays a central role in the planning of river basin management. The quality of the stream at any point depends on several major factors: lithology of the basin, weather conditions, climate, and human impacts. Most of the polluters are located in the big cities next to canal DTD Becej-Bogojevo canal (Odzaci,Vrbas, Srbobran, Becej). Per year, 2900000 m3 of wastewater was discharged into the Becej-Bogojevo section of the DTD canal: 1,4 tCOD, 0,8 0tBOD, 260 kg of nitrogen, 19 kg of phosphorus and 282 kg of suspended solids. Of the total volume of wastewater, 20% comes from industry and 80% from municipal wastewater. Most of the wastewaters from the studied polluters is discharged untreated or insufficiently treated (only primary treatment). This poor quality wastewater threatens the receipients into which its is discharged. Comparison of the wastewater quality results to the Decree on emission limits and deadlines for their achievement, shows that many polluters exceed the limits for all parameters (COD, BOD, nitrogen, phosphorus, suspended solids). On the basis of the physico-chemical analysis of the water from the DTD Becej-Bogojevo canal it can be concluded that the water quality is unsatisfactory. According to the national legislation, the water quality exceeds the values for good potential streams for most parameters at all sampling locatio dissolved oxygen, organic matter and nutrients). Thus, we can conclude that the water in the studied section of the DTD Becej-Bogojevo canal does not meet the criteria for "good ecological potential". The most vulnerable locations are downstream of the Vrbas and downstream of the Becej, while the best quality canal water is at the furthest upstream location (CS Bogojevo). Risk assessment based on monitoring results indicates that the water of the studied section of the DTD Becej-Bogojevo canal is probably at risk of failing to meet the objectives of the Water Framework Directive, as 33% of the analyzed parameters to calculate specific risk ratios were greater than 1, and thus fall into the category of pollutants medium risk. In order to achieve the quality (to achieve good status and good potential), there must be a response from industrial producers, which consists primarily of comprehensively understanding the problems and implementing measures to minimize the impact of these problems.

Replacement of secondary clarification by membrane separation - results with plate and hollow fibre modules

1998 ◽  
Vol 38 (4-5) ◽  
pp. 383-393 ◽  
Author(s):  
Berthold Günder ◽  
Karlheinz Krauth
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Hollow Fibre ◽  
Treated Wastewater ◽  
Stable Operation ◽  
Membrane Systems ◽  
Process Technology ◽  
Mixed Liquor ◽  
Activated Sludge Processes

Submerged membrane systems can replace the final clarification step to separate mixed liquor suspended solids (MLSS) from treated wastewater in the activated sludge processes. Mixed liquor suspended solids concentrations as high as 20 g/l can be maintained compared with the typical 3–4 g/l for conventional activated sludge/secondary clarifier systems. This leads to much smaller reactor volumes. In addition, excellent, solid free effluent qualities can be achieved with this process technology. One major challenge, when applying membrane technology to municipal wastewater treatment systems, is handling the flow variations typically encountered by these systems. This paper reports about the parallel investigation of two membrane-systems installed within a 7 m3 and a 9 m3 bioreactor. One membrane system used submerged plate modules (80 m2 membrane surface), the other hollow fibre modules (83.4 m2). The emphasis of this first investigation was the hydraulic performance and elasticity of the membrane systems. At MLSS concentrations of 15 g/l and hydraulic retention times of 6 hours, flux rates of 15 l/m2 h under permanent operation and up to 30 l/m2 h for short periods of time were achieved (standardised to a temperature of 10°C). A stable operation at these rates could be achieved for a full 4 months period without chemical cleaning of the membranes. Future studies will focus on nutrient removal aspects and the energy consumption of the systems.

scholarly journals Dynamic characterization of a FeCl3-dosed anaerobic membrane bioreactor (AnMBR) treating municipal wastewater

2018 ◽  
Vol 2017 (2) ◽  
pp. 481-491 ◽  
Author(s):  
Qirong Dong ◽  
Wayne Parker ◽  
Martha Dagnew
Keyword(s):  
Membrane Bioreactor ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Pilot Scale ◽  
Delayed Response ◽  
Transient Model ◽  
Mixed Liquor ◽  
Anaerobic Membrane Bioreactor ◽  
Membrane Performance ◽  
The Impact

Abstract A transient study was conducted at pilot scale to assess the impact of Fe dosage on the dynamics of biological and membrane performance of an anaerobic membrane bioreactor (AnMBR) treating authentic municipal wastewater. A transient model of the AnMBR system was employed to assist with interpretation of the observed responses in the mixed liquor under different FeCl3 dosages. A high dosage (43 mg FeCl3/LSewage) resulted in a significant accumulation of fixed suspended solids and volatile suspended solids (VSS) and reduction of colloidal COD in the mixed liquor. The elevated dosages appeared to reduce the biodegradability of VSS that was present in the raw wastewater. Intermediate dosages of FeCl3 (21–12 mg/L) had less effect on these responses and did not appear to affect VSS biodegradation. Membrane performance was significantly affected by FeCl3 dosage as indicated by reversible resistance (RR) and physically irreversible resistance (IR). RR was closely related to the colloidal COD in the mixed liquor, thus responded quickly to Fe dosage. Physically, IR had a delayed response to changes in the colloidal COD concentrations in the mixed liquor and this was attributed to the effect of slow mass transfer of colloidal matter between the mixed liquor and the membrane.

Treatment of Petroleum Refinery Wastewater Using Extended Aeration Activated Sludge

2014 ◽  
Vol 13 ◽  
pp. 1-7 ◽  
Author(s):  
Hayder Gasim ◽  
Abdur Rahman Megat Mohamed Amin Megat ◽  
Rahman Mohamed Kutty Shamsul
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Petroleum Refinery ◽  
Oxygen Demand ◽  
Organic Loading Rate ◽  
Refinery Wastewater ◽  
Environmental Aspect ◽  
Mixed Liquor ◽  
Petroleum Refinery Wastewater

The petroleum refinery wastewater biological treatment is widely investigated because of the potential complete mineralization and environmental aspect. In this study, petroleum refinery wastewater was treated in an extended aeration activated sludge (EAAS) reactor A, operated in parallel with EAAS reactor B as a control, fed with municipal wastewater. The chemical oxygen demand (COD) organic loading rate (OLR) of the refinery wastewater in reactor B was approximately 0.057 kg COD/m3·d compared to reactor A of 0.004 kg COD/m3·d throughout the study period. The flowrate for both reactors was maintained at 21.4 L/day. Food to microorganism (F/M) ratio, COD, mixed liquor suspended solids (MLSS), and mixed liquor volatile suspended solids (MLVSS) were monitored throughout the study period. The result indicated high removal efficiency of organic matter of approximately 87% as COD with 2582 mg/L of the petroleum refinery wastewater as influent and 140 mg/L as effluent.

Study on the performance of an up-flow aerated biofilter (UAB) in municipal wastewater treatments

1994 ◽  
Vol 30 (11) ◽  
pp. 25-33 ◽  
Author(s):  
Yoshimasa Watanabe ◽  
Satoshi Okabe ◽  
Tomochika Arata ◽  
Yuji Haruta
Keyword(s):  
Organic Matter ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Unique Feature ◽  
Aeration Rate ◽  
Loading Rates ◽  
Hydraulic Loading ◽  
Running Cost ◽  
And Performance ◽  
Activated Sludge Systems

A comprehensive wastewater treatment system that accomplishes oxidation of organic matter, nitrification, and denitrification was developed, and its characteristics and performance were investigated. A municipal wastewater was treated by an up-flow aerated biofilter (UAB), in which biofilms were developed on stainless meshes installed horizontally. This UAB exhibited a great potential ability of oxidation of organic matter, SS stabilization, and nitrification due to a unique aeration mechanism giving high DO concentrations with relatively low aeration rates. Another unique feature of the UAB was that attached biofilms on stainless meshes physically filtered out and/or adsorbed suspended solids in the wastewater in addition to the biological oxidation of organic matter. A stable nitrification could be achieved at HRT=10 hours corresponding to a hydraulic loading of 86 L m−2 d−1 and at a ratio of aeration rate to wastewater flow rate (A/W) of 2, which is considerably low as compared to aeration rates of typical activated sludge systems. This UAB system also could handle relatively high hydraulic loading rates. The UAB used in this study still have enough space to install more stainless meshes so as to reduce hydraulic loading rates resulting in the reduction of HRT and aeration rate, which leads to improvement of the system performance as well as reduction of the running cost.

Sediment transport under dry weather conditions in a small sewer system

1998 ◽  
Vol 37 (1) ◽  
pp. 155-162
Author(s):  
Flemming Schlütter ◽  
Kjeld Schaarup-Jensen
Keyword(s):  
Sediment Transport ◽  
Field Data ◽  
Field Measurements ◽  
Weather Conditions ◽  
Sewer System ◽  
Transport Models ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Initial Results

Increased knowledge of the processes which govern the transport of solids in sewers is necessary in order to develop more reliable and applicable sediment transport models for sewer systems. Proper validation of these are essential. For that purpose thorough field measurements are imperative. This paper renders initial results obtained in an ongoing case study of a Danish combined sewer system in Frejlev, a small town southwest of Aalborg, Denmark. Field data are presented concerning estimation of the sediment transport during dry weather. Finally, considerations on how to approach numerical modelling is made based on numerical simulations using MOUSE TRAP (DHI 1993).

Municipal wastewater treatment with pond–constructed wetland system: a case study

2005 ◽  
Vol 51 (12) ◽  
pp. 325-329 ◽  
Author(s):  
X. Wang ◽  
X. Bai ◽  
J. Qiu ◽  
B. Wang
Keyword(s):  
Constructed Wetland ◽  
Municipal Wastewater ◽  
Municipal Wastewater Treatment ◽  
Oxidation Pond ◽  
System A ◽  
Treated Effluent ◽  
Wetland System ◽  
Oxidation Ponds ◽  
Better Than

The performance of a pond–constructed wetland system in the treatment of municipal wastewater in Kiaochow city was studied; and comparison with oxidation ponds system was conducted. In the post-constructed wetland, the removal of COD, TN and TP is 24%, 58.5% and 24.8% respectively. The treated effluent from the constructed wetland can meet the Chinese National Agricultural and Irrigation Standard. The comparison between pond–constructed wetland system and oxidation pond system shows that total nitrogen removal in a constructed wetland is better than that in an oxidation pond and the TP removal is inferior. A possible reason is the low dissolved oxygen concentration in the wetland. Constructed wetlands can restrain the growth of algae effectively, and can produce obvious ecological and economical benefits.

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