Para-chlorophenol containing synthetic wastewater treatment in an activated sludge unit: Effects of hydraulic residence time

2007 ◽  
Vol 84 (1) ◽  
pp. 20-26 ◽  
Author(s):  
Fikret Kargi ◽  
Isil Konya
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Residence Time ◽  
Synthetic Wastewater ◽  
Hydraulic Residence Time

Suspended carrier technology allows upgrading high-rate activated sludge plants for nitrogen removal via process intensification

2000 ◽  
Vol 41 (4-5) ◽  
pp. 5-12 ◽  
Author(s):  
E.v. Münch ◽  
K. Barr ◽  
S. Watts ◽  
J. Keller
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Residence Time ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plant ◽  
Pilot Plant ◽  
Treatment Plant ◽  
Carbon Removal ◽  
Suspended Carrier ◽  
Plastic Media

The Oxley Creek wastewater treatment plant is a conventional 185,000 EP BOD removal activated sludge plant that is to be upgraded for nitrogen removal to protect its receiving water bodies, the Brisbane River and Moreton Bay. Suspended carrier technology is one possible way of upgrading this activated sludge wastewater treatment plant for nitrogen removal. Freely moving plastic media is added to the aeration zone, providing a growth platform for nitrifying bacteria and increasing the effective solids residence time (SRT). This paper presents the results from operating a pilot plant for 7 months at the Oxley Creek WWTP in Brisbane, Australia. Natrix Major 12/12 plastic media, developed by ANOX (Lund, Sweden), was trialed in the pilot plant. The pilot plant was operated with a mixed liquor suspended solids concentration of 1220 mg/L and a total hydraulic residence time of 5.4 hours, similar to the operating conditions in the full-scale Stage 1&2 works at the Oxley Creek WWTP. The plastic carriers were suspended in the last third of the bioreactor volume, which was aerated to a DO setpoint of 4.0 mg/L. The first third of the bioreactor volume was made anoxic and the second third served for carbon removal, being aerated to a DO setpoint of 0.5 mg/L. The results from the pilot plant indicate that an average effluent total inorganic nitrogen concentration (ammonia-N plus NOx−N) of less than 12 mg/L is possible. However, the effluent ammonia concentrations from the pilot plant showed large weekly fluctuations due to the intermittent operation of the sludge dewatering centrifuge returning significant ammonia loads to the plant on three days of the week. Optimising denitrification was carried out by lowering the DO concentration in the influent and in the carbon removal reactor. The results from the pilot plant study show that the Oxley Creek WWTP could be upgraded for nitrogen removal without additional tankage, using suspended carrier technology.

scholarly journals Removal of organics and metal ion nanoparticles from synthetic wastewater by activated sludge process (ASP)

2014 ◽  
Author(s):  
Tarunveer Singh ◽  
Shubhanshu Jain
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Metal Ions ◽  
Organic Contaminants ◽  
Metal Ion ◽  
Treatment Plant ◽  
Poor Quality ◽  
Treated Wastewater ◽  
Synthetic Wastewater ◽  
Batch Reactors

Adsorption technique is widely used for removal of toxic organic contaminants from aqueous streams. Owing to the hazardous or otherwise undesirable characteristics of phenolic compounds in particular, their presence in wastewater from municipal and industrial discharge is one of the most important environmental issue. The discharge of poor quality effluents by the chemical-based laboratories and refineries in India is posing a serious threat to water sources and wastewater treatment installations alike. Our study was set up in the Indo - French Unit for Water & Wastewater Technologies (IFUWWT), IIT Delhi. The main objective of this study was to assess the efficiency of a laboratory-scale activated sludge treatment process in producing a final effluent conforming to regulatory standards of Central Pollution Control Board, India (CPCB norms) with regards to COD and metal ion loads. The study was conducted in three principal stages: characterization of wastewater containing nanoparticles; treatability studies of laboratory generated discards and investigations of heavy metal ions before and after treatment. The various raw effluent parameters analyzed were COD, BOD, F/M ratio, Sludge Value Index, Total Solids and concentrations of Cu, Ag and Zn. Studies were conducted using two aerobic sequencing batch reactors (SBR). MLSS of the aeration basin was calculated to be 7180±261.3 mg/L while the F/M ratio was kept down to 0.1560±.0149; besides, an SVI of 107.24 mL/g complied with the state of bioreactor’s sludge. These set of values suggested to set an extended aeration processes for the reactors. Accordingly, the detention time in aeration basin was 24 hours. The results showed over 98% influent COD reduction and nearly 100% removal of metal ions. The sample used was operated on sludge collected from Vasant Kunj Wastewater Treatment plant. Based on the results from waste characterization and treatability studies, it was decided that the mixed liquor discharged in the activation tank should have glucose solution and laboratory discarded sample in 1:1 ratio. The reactor was operated on a glucose fed batch basis for 30 days. For the sake of metal analysis, the digested water samples were analyzed for the presence of copper, silver and zinc using the ElementAS AAS4141 Atomic Absorption Spectrophotometer (by Electronics Corporation of India Ltd). The biosorption capacities were found to be over 95% in all the cases with the minimum correlation coefficient for calibration curve being 0.9811. Such a high sludge yield is suggestive of the fact that heavy metals are in very low concentrations in the considered carboy sample. Because of these insignificant values, the amount of metal ions introduced to the system gets adsorbed almost completely, hence leaving behind no metal ion within the supernatant. Well-treated wastewater has enormous potential as a source of water for crops, households and industry.

scholarly journals Coke oven wastewater treatment by two activated sludge systems

2013 ◽  
Vol 8 (1) ◽  
pp. 16-22
Keyword(s):  
Organic Matter ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Coke Oven ◽  
Synthetic Wastewater ◽  
Removal Efficiencies ◽  
Activated Sludge Systems

In this study two bench scale activated sludge systems were used, a CSTR and an SBR for the treatment of coke – oven wastewater. Both reactors were inoculated with activated sludge from a municipal wastewater treatment plant. At the first stages of operation, reactors were feed by a mixture of municipal wastewater and synthetic wastewater. Full acclimatization of the microorganisms to synthetic wastewater was achieved in 60 days. The operation of the reactors was divided into three distinct periods. The first period was characterized by the treatment of high organic but non-toxic synthetic wastewater. During this period COD and BOD5 removal efficiencies reached 95 and 98% respectively, in both reactors. Nutrient removal was better in the SBR reactor rather than in the CSTR. In the second period phenol was added in concentrations up to 300 mg l-1. Degradation of phenol started about the 20th day after its introduction to the reactors. In this period no effects of phenol to nutrient removal were observed, whereas the removal efficiency of organic matter in both reactors was slightly decreased. During the third period phenol concentrations of the influent were gradually increased to 1000 mg l-1, while cyanide and thiocyanite were added to the influent composition to concentrations reaching concentrations of 20 and 250 mg l-1 respectively. The composition of the influent of this period was a full assimilation of coke oven wastewater. Introduction of increased phenol concentrations along with cyanide compounds initiated irreversible effects on the activated sludge microfauna of the CSTR causing inherent problems to the treatment process, while SBR showed greater capacity to withstand and degrade toxic compounds. The beginning of this period was characterized by decreased settleability of the suspended solids as well as decrease of organic matter and nutrient removal efficiencies. Monitoring of the effluent characteristics during this period reported over 90% for organic load, 85% of nutrient removal and over 90% of phenol and cyanide removal in SBR, while the removal efficiencies for the CSTR were 75, 65 and 80% respectively.

Integration of performance, molecular biology and modeling to describe the activated sludge process

1998 ◽  
Vol 37 (4-5) ◽  
pp. 223-229 ◽  
Author(s):  
V. Urbain ◽  
B. Mobarry ◽  
V. de Silva ◽  
D. A. Stahl ◽  
B. E. Rittmann ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Molecular Biology ◽  
Activated Sludge ◽  
Residence Time ◽  
Municipal Wastewater ◽  
Treated Wastewater ◽  
Integrated Analysis ◽  
Activated Sludge Process ◽  
Hydraulic Residence Time ◽  
Technical Problems

To study process performance and population dynamics in activated sludge, a pilot-scale Membrane Bioreactor (MBR) was installed in a municipal wastewater treatment plant (Aubergenville, France). Since no solids losses occur in the MBR effluent, the sludge residence time (SRT) can be: i) easily controlled by means of the sludge withdrawal, and ii) dissociated from the hydraulic residence time (HRT). A complete characterization of this activated sludge system was performed at three sludge ages (5, 10 and 20 days). Raw and treated wastewater quality, as well as sludge concentration, was analyzed, nucleic probe analysis was performed to determine the heterotrophic and nitrifier populations, and the results were compared to the output from a multispecies model that integrates substrate removal kinetics and soluble microbial products (SMP) production/consumption. This paper presents an integrated analysis of the activated sludge process based on chemical, molecular biology, and mathematical tools. The model was able to describe the MBR system with a high degree of accuracy, in terms of COD removal and nitrification, as well as sludge production and population dynamics through the ratio of active nitrifiers/bacteria. Both steady-state and transient conditions could be described accurately by the model, except for technical problems or sudden variations in the wastewater composition.

scholarly journals Influence of Wastewater Type in the Effects Caused by Titanium Dioxide Nanoparticles in the Removal of Macronutrients by Activated Sludge

2021 ◽  
Author(s):  
Pabel Cervantes-Avilés ◽  
Ayman N. Saber ◽  
Abrahan Mora Polanco ◽  
Jurgen Mahlknecht ◽  
Germán Cuevas-Rodríguez
Keyword(s):  
Titanium Dioxide ◽  
Wastewater Treatment ◽  
Cell Membrane ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
Titanium Dioxide Nanoparticles ◽  
Synthetic Wastewater ◽  
Nitrogen And Phosphorus ◽  
Floc Size ◽  
Nitrite Production

Abstract The imminent arrival of nanoparticles (NPs) to the wastewater treatment plants (WWTP) brings concern about their effects. In this work, the effects of titanium dioxide (TiO2) NPs in the removal of carbon, nitrogen, and phosphorus by activated sludge bioreactors during the treatment of synthetic, raw and filtered wastewater were evaluated. The floc size, compaction of sludge, and morphological interactions between sludge and NPs were also evaluated. The main effect was observed in the ammoniacal nitrogen removal, which was inhibited up to 22% for all types of wastewater in the presence of TiO2 NPs. While nitrite production deficiencies were observed for real wastewaters experiments, nitrate formation was mainly affected for synthetic wastewater. The removal of organic matter was affected by TiO2 NPs in lower level (up to 6%) than nitrogen removal, especially during treatment of raw wastewater. The removal of orthophosphate was improved in presence of NPs 34%, 16% and 55% for synthetic, raw, and filtered wastewater, respectively. The compaction of the sludge was also a positive effect, which enhanced as the concentration of NPs increased without alterations in the floc size for all types of wastewater. Based on TEM and STEM imaging, the main interaction of TiO2 NPs with activated sludge flocs was mainly the adsorption of NPs on the cell membrane. This means that NPs can disrupt the cell membrane during aerobic wastewater treatment. The effects of NPs on macronutrient removal depended on wastewater characteristics. The use of realistic matrices is highly encouraged for ecotoxicological experiments.

Enhancing nitrification in North American activated sludge plants

2000 ◽  
Vol 41 (9) ◽  
pp. 97-105 ◽  
Author(s):  
G.T. Daigger ◽  
D.S. Parker
Keyword(s):  
Activated Sludge ◽  
Residence Time ◽  
North American ◽  
Biological Process ◽  
Full Scale ◽  
Activated Sludge Process ◽  
Hydraulic Residence Time ◽  
Nitrification Process ◽  
Mechanistic Basis ◽  
Space Requirements

Many plant owners, operators and designers consider the nitrifying activated sludge process as being a high hydraulic residence time (HRT) process. However, in recent years a number of techniques have been developed to enhance the performance of activated sludge plants for nitrification. The result, when the proper combination of these techniques is used, can be a significant reduction in the biological process hydraulic residence time and a corresponding reduction in facility costs and space requirements. Several of these factors are discussed in this paper, including a discussion of the mechanistic basis for each technique and its impact on nitrification process sizing. Some full-scale North American examples are also discussed.

Excess sludge reduction in activated sludge processes by integrating biomass alkaline heat treatment

2001 ◽  
Vol 44 (2-3) ◽  
pp. 437-444 ◽  
Author(s):  
M. Rocher ◽  
G. Roux ◽  
G. Goma ◽  
A. Pilas Begue ◽  
L. Louvel ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Waste Treatment ◽  
Ralstonia Eutropha ◽  
Synthetic Wastewater ◽  
Waste Activated Sludge ◽  
Excess Sludge ◽  
Wastewater Treatment Process ◽  
Activated Sludge Processes

With new EC regulations, alternative treatment and disposal techniques of the excess sludge produced by activated sludge wastewater treatment plants have to be developed. To decrease activated sludge production yield, microbial cell lysis can be amplified to enhance cryptic growth (biomass growth on lysates). Cell breakage techniques (thermal, alkaline and a combination) were studied to generate Ralstonia eutropha (strain model) and waste activated sludge lysates and to evaluate their biodegradability. Gentle treatment conditions by alkaline waste treatment (20 min at 60°C and pH 10 by NaOH addition) allowed waste activated sludge to be solubilized by a two step process (instantaneous and post-treatment) giving a dissolved organic carbon released by the total suspended solids treated of 267 mgDOC.g-1TSS. The biodegradation of the soluble fraction of the lysates by fresh sludge reached 75 and 90% after 48 and 350 hrs of incubation respectively. A validation on a laboratory scale by insertion of a liquor alkaline heat treatment loop in a biological synthetic wastewater treatment process was carried out. A reduction of 37% of the excess sludge was obtained without altering the purification yield of the process.

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