scholarly journals Combined Anaerobic-Aerobic Bacterial Degradation of Dyes

2010 ◽  
Vol 7 (3) ◽  
pp. 739-744 ◽  
Author(s):  
R. Wilfred Sugumar ◽  
Sandhya Sadanandan
Keyword(s):  
Mixed Culture ◽  
Bacterial Degradation ◽  
Acid Orange 7 ◽  
Anaerobic Reactor ◽  
Anaerobic Microorganisms ◽  
Degradation Of Dyes ◽  
Textile Dyeing ◽  
Nitrification Process ◽  
Aerobic Reactor ◽  
Reactive Red 2

Wastewaters from the dye baths of a non-formal textile-dyeing unit containing C.I. Acid Orange 7 and C.I. Reactive Red 2 were subjected to degradation in a sequential anaerobic-aerobic treatment process based on mixed culture of bacteria. The technical samples of the dyestuffs and the dye bath wastes were treated in an anaerobic reactor, using an adapted mixed culture of anaerobic microorganisms. The dyestuffs were biotransformed into colourless substituted amine metabolites in the reactor. The biotransformation was assisted by co-metabolic process. The amine metabolites did not undergo further degradation in the anaerobic reactor. The effluent from the anaerobic reactor was treated in an aerobic rotating biological contactor and the amine metabolites were found to undergo complete mineralization. This two stage treatment resulted in 94% elimination of dissolved organic carbon. In addition, 85% of organic nitrogen was converted into nitrate in the aerobic reactor during nitrification process.

An improved small sewage treatment plant for biological purification of wastewater

1994 ◽  
Vol 29 (12) ◽  
pp. 23-29 ◽  
Author(s):  
G. Voigtländer ◽  
E.-P. Kulle
Keyword(s):  
Energy Supply ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Septic Tank ◽  
Additional Energy ◽  
Anaerobic Reactor ◽  
Step Process ◽  
Operational Costs ◽  
Aerobic Reactor

The paper presents a small sewage treatment plant (package plant) operating without additional energy. Purification of sewage is achieved in a three-step process: sedimentation tank, anaerobic reactor and wastewater pond or aerobic reactor. The efficiency of the anaerobic reactor - in contrast to the efficiency of a common septic tank - is significantly increased by using fixed biomass systems. Further degradation of sewage compounds by adhering microorganisms occurs in pond or aerobic reactor. The bed for the aerobic biomass is made of a semipermeable plastic film and arranged in order to ensure simultaneous supply of oxygen. The three pilot plants are showing different results. The main aims of research i.e. lowering of operational costs, energy supply, minimizing of maintenance expenditure and cleaning work, reliability of degradation efficiency have been achieved so far for the anaerobic reactor.

CHARACTERISATION OF THE NITRIFICATION PROCESS FOR DESIGN PURPOSES

1994 ◽  
Vol 30 (4) ◽  
pp. 47-56 ◽  
Author(s):  
O. Sinkjær ◽  
L. Yndgaard ◽  
P. Harremoës ◽  
J. L. Hansen
Keyword(s):  
Kinetic Theory ◽  
Nitrification Rate ◽  
Experimental Basis ◽  
Batch Tests ◽  
Mode Of Operation ◽  
Nitrification Process ◽  
Aerobic Reactor ◽  
The City ◽  
Specific Evaluation ◽  
Aerobic Sludge

Pilot plant experiments have been performed over a period of four years in order to establish an experimental basis for the upgrading of the treatment plants of the city of Copenhagen to nitrogen removal. The design chosen is based on the alternating mode of operation. Nitrification rates have been determined in batch tests on activated sludge extracted from the pilot plants and through the measuring of transient concentrations during the alternating mode of operation in the aerobic reactor. The data have been nonnalised to standard conditions by correcting them according to the kinetic theory. By monitoring the normalised nitrification rate it could be established that the nitrification process was occasionally inhibited. The aerobic sludge age required to maintain nitrification has been estimated. A specific evaluation has been made of the sensitivity of the required sludge age to the oxygen concentration and temperature.

scholarly journals Use of semi-conducting bismuth sulfide as a photocatalyst for degradation of rose bengal

2011 ◽  
Vol 30 (2) ◽  
pp. 229 ◽  
Author(s):  
Shweta Sharma ◽  
Rakshit Ameta ◽  
R. K. Malkani ◽  
Suresh C. Ameta
Keyword(s):  
Light Intensity ◽  
Rose Bengal ◽  
Bismuth Sulfide ◽  
Optimum Conditions ◽  
First Order ◽  
First Order Kinetics ◽  
Degradation Of Dyes ◽  
Textile Dyeing ◽  
Rate Of Reaction ◽  
Pseudo First Order

Different methods have been adopted for the removal and degradation of dyes from effluents of textile, dyeing and printing industries. These methods have their own merits and drawbacks. In the present investigation, bismuth sulfide has been used as a photocatalyst for the degradation of rose Bengal. The effect of different parameters like the pH, concentration of dye solution, amount of semiconductor and light intensity on the rate of reaction has been investigated. The reaction follows pseudo-first order kinetics. The optimum conditions were obtained as: [rose Bengal] = 1.60·10–5 M; Bi2S3 = 0.10 g; pH = 8.5, and light intensity = 50.0 mW·cm–2. The rate constant was 4.68·10–5 sec–1. A mechanism has been proposed for the degradation of rose Bengal involving hydroxyl radicals.

Biological nitrogen removal from industrial wastewater discharged from metal recovery processes

2001 ◽  
Vol 44 (2-3) ◽  
pp. 171-180 ◽  
Author(s):  
A. Hirata ◽  
Y. Nakamura ◽  
S. Tsuneda
Keyword(s):  
Total Nitrogen ◽  
Residence Time ◽  
Nitrogen Removal ◽  
Nitrogen Concentration ◽  
Industrial Wastes ◽  
Biological Nitrogen Removal ◽  
Hydraulic Residence Time ◽  
Anaerobic Reactor ◽  
Aerobic Reactor ◽  
Biological Nitrogen

The wastewater generated from the processes of recovering precious metals from industrial wastes contains high concentrations of acids and alkalis such as nitric acid and aqueous ammonia, and of salts such as sodium chloride and sodium sulfate. Biological nitrogen removal from this wastewater was attempted by using a circulating bioreactor system equipped with an anaerobic packed bed and an aerobic three-phase fluidized bed. As a result of acclimating microorganisms with change of the hydraulic residence time, this system effectively removed nitrogen from diluted wastewater (T-N: from 2,000 to 4,000 g/m3), such that the total nitrogen concentration in the effluent met the sewage discharge control criteria in Japan (240 g/m3). The removal ratio of total nitrogen was 90% to 98% and that of ammonia was 80% to 92%. In addition, the characteristic equations for biological treatment were applied to this system on the assumption that both reactions of denitrification in the anaerobic reactor and nitrification in the aerobic reactor can be approximated to a first-order reaction. This simplified approach successfully led to a new analytical method for simulating the optimum volume ratio of anaerobic reactor to aerobic reactor for minimizing the total hydraulic residence time.

Treatment of packaging board whitewater in anaerobic/aerobic biokidney

2005 ◽  
Vol 52 (10-11) ◽  
pp. 289-298 ◽  
Author(s):  
T. Alexandersson ◽  
Å. Malmqvist
Keyword(s):  
Removal Efficiency ◽  
Pilot Plant ◽  
Combined Treatment ◽  
Organic Load ◽  
Anaerobic Reactor ◽  
Loading Level ◽  
Total Process ◽  
Thermophilic Conditions ◽  
Aerobic Reactor ◽  
Plant Trial

Whitewater from production of packaging board was treated in a combined anaerobic/aerobic biokidney, both in laboratory scale and pilot plant experiments. Both the laboratory experiments and the pilot plant trial demonstrate that a combined anaerobic/aerobic process is suitable for treating whitewater from a packaging mill. It is also possible to operate the process at the prevailing whitewater temperature. In the laboratory under mesophilic conditions the maximal organic load was 12kg COD/m3*d on the anaerobic reactor and 6.7kg COD/m3*d on the aerobic reactor. This gave a hydraulic retention time, HRT, in the anaerobic reactor of 10 hours and 2 hours in the aerobic reactor. The reduction of COD was between 85 and 90% after the first stage and the total reduction was between 88 to 93%. Under thermophilic conditions in the laboratory the organic load was slightly lower than 9.6COD/m3*d and between 10 and 16COD/m3*d, respectively. The HRT was 16.5 and 3.4 hours and the removal was around 75% after the anaerobic reactor and 87% after the total process. For the pilot plant experiment at a mill the HRT in the anaerobic step varied between 3 and 17 hours and the corresponding organic load between 4 and 44kgCOD/m3*d. The HRT in the aerobic step varied between 1 and 6 hours and the organic load between 1.5 and 26kgCOD/m3*d. The removal of soluble organic matter was 78% in the anaerobic step and 86% after the combined treatment at the lowest loading level. The removal efficiency at the highest loading level was about 65% in the anaerobic step and 77% after the aerobic step. In the pilot plant trial the removal efficiency was not markedly affected by the variations in whitewater composition that were caused by change of production. The variations, however, made the manual control of the nutrient dosage inadequate and resulted in large variations in effluent nutrient concentration. This demonstrates the need for an automatic nutrient dosage system. The first step towards such a system was to evaluate two different on-line instruments. Both had severe stability problems, which made them unsuitable as parts in a system for control of the nutrient dosage.

Cyclic bioreactors - a discussion on technology application and possible future developments

2004 ◽  
Vol 4 (1) ◽  
pp. 103-109
Author(s):  
W.J. Ng
Keyword(s):  
Wastewater Treatment ◽  
Equipment Selection ◽  
Technology Application ◽  
Anaerobic Reactor ◽  
Future Developments ◽  
Aerobic Reactor ◽  
Wastewater Treatment Systems

Wastewater treatment systems based on cyclic reactors started to be applied more widely in Asia about two decades ago. A number of variants have been introduced but the focus of this paper is on the intermittent feed-intermittent decant variant, the SBR. Based on the basic SBR concept, specific reactor configurations which have been introduced include the pretreatment anaerobic reactor (anSBR), the aerobic reactor (aeSBR), and the sludge digester (SBD). This paper discusses some of the issues around the argument for selecting the SBR - particularly the aeSBR, equipment which are unique to this cyclic reactor, the concerns around such equipment selection, operating difficulties, and the possible future developments with this reactor concept.

Biodegradation of Wool Scouring Effluent on a Laboratory Scale

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2101-2104 ◽  
Author(s):  
R. A. Oellermann ◽  
T. Ronen ◽  
V. Meyer
Keyword(s):  
Chemical Oxygen Demand ◽  
Retention Time ◽  
Suspended Solids ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Rotating Biological Contactor ◽  
Anaerobic Reactor ◽  
Biomass Retention ◽  
Aerobic Reactor ◽  
Mixed Systems

A continuously fed, sequential anaerobic-aerobic-aerobic reactor system was used to treat wool scouring effluent. The chemical oxygen demand (COD) in the anaerobic reactor was reduced from 30500 mg/ℓ to 3000-5000 mg/ℓ. In the first aerobic reactor this was further reduced to 1200-1800 mg COD/l. The final discharge from the second aerobic reactor had a COD of 500-1000 mg/ℓ at a hydraulic retention time of 2-3 d. Nitrification was erratic but sufficient to reduce the ammonia-N to levels of 20 mg/ℓ and less. Mixed liquor suspended solids and volatile suspended solids could be maintained at sufficiently high levels in completely mixed systems and efficient biomass retention in the aerobic rotating biological contactor resulted in an overall removal of 98.4% COD.

Experimental test to evaluate performance of an anaerobic reactor provided with an external membrane unit

1998 ◽  
Vol 38 (8-9) ◽  
pp. 385-392 ◽  
Author(s):  
S. Elmaleh ◽  
L. Abdelmoumni
Keyword(s):  
Membrane Fouling ◽  
Industrial Development ◽  
Particle Deposition ◽  
Membrane Surface ◽  
Cross Flow ◽  
Membrane Unit ◽  
Anaerobic Reactor ◽  
Flux Decline ◽  
Aerobic Reactor ◽  
Sludge Production

The coupling of a wastewater treatment anaerobic reactor with a microfiltration or ultrafiltration membrane is particularly attractive: lower sludge production than in an aerobic reactor, methane production and dissociation of the mean residence times of the different phases. However, the industrial development of such a process is hampered by membrane fouling which can be a result of many causes and require a comprehensive study especially fouling by anaerobic suspensions. In order to simplify the study, the different phases of anaerobic oxidation were separated and this work is focused on the filtration of an anaerobic suspension fed with acetic acid as the sole carbon source at 2 g/l TOC. The effluent quality was excellent without sludge production in spite of large variation of the liquid phase space time. The tested filtration elements were tubular Carbosep membranes. The M14 membrane showed the greatest flux of 120 l/m2 h at 0.5 bar and 25 Pa shear stress and the flux increased to 180 l/m2 h when a baffle was introduced. The main fouling mechanism appears to be the particle deposition on the membrane surface as no flux decline was observed at higher cross-flow velocity.

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