The use of the kaldnes suspended carrier process in treatment of wastewaters from the forest industry

1997 ◽  
Vol 35 (2-3) ◽  
pp. 123-130 ◽  
Author(s):  
Eva Dalentoft ◽  
Peter Thulin
Keyword(s):  
Activated Sludge ◽  
Pilot Plant ◽  
Operating Costs ◽  
Forest Industry ◽  
Activated Sludge Process ◽  
Combination Process ◽  
In Series ◽  
Suspended Carrier ◽  
Highly Loaded ◽  
Pilot Plant Study

One pilot plant study and two full scale studies have been carried out seeking for the optimal use of the Kaldnes suspended carrier process in treatment of wastewaters from the forest industry. The wastewater used in all three cases came from secondary fiber mills. The studies show that the Kaldnes process as a highly loaded stage (typically 15-25 kg COD/m3·d) in series with an activated sludge stage forms an efficient, stable and competitive combination process both regarding investment and operating costs. This is especially true when treating wastewaters with a composition that makes them unsuited for treatment in an activated sludge process. The flexibility and compactness of the Kaldnes suspended carrier process also makes it an ideal choice for upgrading of existing treatment plants.

Comparison of Aerobic and Anoxic-Aerobic Digestion of Waste Activated Sludge

1985 ◽  
Vol 17 (8) ◽  
pp. 1475-1478 ◽  
Author(s):  
A P. C. Warner ◽  
G. A. Ekama ◽  
G v. R. Marais
Keyword(s):  
Experimental Data ◽  
Activated Sludge ◽  
Waste Activated Sludge ◽  
Activated Sludge Process ◽  
Cycle Times ◽  
Waste Sludge ◽  
Volatile Solids ◽  
In Series ◽  
Flow Through ◽  
Theoretical Simulations

The laboratory scale experimental investigation comprised a 6 day sludge age activated sludge process, the waste sludge of which was fed to a number of digesters operated as follows: single reactor flow through digesters at 4 or 6 days sludge age, under aerobic and anoxic-aerobic conditions (with 1,5 and 4 h cycle times) and 3-in-series flow through aerobic digesters each at 4 days sludge age; all digesters were fed draw-and-fill wise once per day. The general kinetic model for the aerobic activated sludge process set out by Dold et al., (1980) and extended to the anoxic-aerobic process by van Haandel et al., (1981) simulated accurately all the experimental data (Figs 1 to 4) without the need for adjusting the kinetic constants. Both theoretical simulations and experimental data indicate that (i) the rate of volatile solids destruction is not affected by the incorporation of anoxic cycles and (ii) the specific denitrification rate is independent of sludge age and is K4T = 0,046(l,029)(T-20) mgNO3-N/(mg active VSS. d) i.e. about 2/3 of that in the secondary anoxic of the single sludge activated sludge stystem. An important consequence of (i) and (ii) above is that denitrification can be integrated easily in the steady state digester model of Marais and Ekama (1976) and used for design (Warner et al., 1983).

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.

Dimensioning of Aerated Grit Chambers and Use as a Highly Loaded Activated Sludge Process

1989 ◽  
Vol 21 (4-5) ◽  
pp. 13-22
Author(s):  
Jorg Londong
Keyword(s):  
Activated Sludge ◽  
Pilot Scale ◽  
Air Injection ◽  
Activated Sludge Process ◽  
Cross Section Area ◽  
Section Area ◽  
Degree Of Separation ◽  
Highly Loaded ◽  
Adsorption Stage

The aerated grit chamber has long been used to separate sand from sewage. Nevertheless, there are no definite and uniform recommendations for dimensioning, and there is little information in the literature about the degree of separation attainable. Thus, principles for dimensioning and the possible degree of separation are derived from measurements of large pilot scale plants, two-dimensional models, and existing aerated grit chambers. The following values for dimensioning were found in this work: a detention period of about 20 minutes; a width to depth ratio (w/d) of about 0.8; a minimal and maximal cross section area between 1 and about 7 m2; a flow velocity of 20 cm/s at the bottom of the aerated grit chamber. Simple formulae for the determination of the required amount of air can be given in relation to the w/d ratio, the depth of air injection and the kind of aeration used (fine or coarse bubble). The simultaneous use of an aerated grit chamber as an adsorption stage (highly loaded activated sludge process) is possible without additional air being required to maintain the velocity at the bottom of the grit chamber. For purely aerobic operation, however, the amount of air has to be increased.

Improvement of ammonia removal in activated sludge process with feedforward-feedback aeration controllers

2006 ◽  
Vol 53 (4-5) ◽  
pp. 125-132 ◽  
Author(s):  
Darko Vrečko ◽  
Nadja Hvala ◽  
Aljaž Stare ◽  
Olga Burica ◽  
Marjeta Stražar ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Pilot Plant ◽  
Pi Controller ◽  
Ammonia Removal ◽  
Activated Sludge Process ◽  
Aerobic Reactor

In the paper three linear aeration controllers that can be easily implemented are presented and evaluated on the activated sludge process pilot plant. Controllers differ according to the information that is used about the process, which can be oxygen in the last aerobic reactor, ammonia in the last aerobic reactor and ammonia in the influent. The aeration controllers that are addressed are: oxygen cascade PI controller, ammonia cascade PI controller and ammonia feedforward-cascade PI controller. Experiments show that, in comparison with the oxygen cascade PI controller, the ammonia cascade PI controller allows better control of effluent ammonia and airflow savings of around 23%, while the ammonia feedforward-cascade PI controller gives the best reduction of ammonia peaks and can save up to 45% of the airflow.

Experience with Two-Stage Activated Sludge Plants for Industrial Wastewaters in Korea

1992 ◽  
Vol 25 (4-5) ◽  
pp. 427-428 ◽  
Author(s):  
R. Schulze-Rettmer ◽  
S. S. Kim ◽  
S. S. Son
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Pilot Plant ◽  
Treatment Plant ◽  
Activated Sludge Process ◽  
Two Stage ◽  
Industrial Wastewaters ◽  
Textile Dyeing ◽  
One Year

The two-stage activated sludge process (AB-process, i.e. adsorption activated sludge process) invented by Boehnke was successfully applied to several municipal and industrial wastewaters in Korea. The first large wastewater treatment plant for the combined effluents of 22 textile dyeing companies was constructed in Taegu and started operation in 1989. Two years earlier pilot plant runs were performed. The AB-process proved to be superior to any other activated sludge process. BOD was reduced from 1200 mg/l down to 24 mg/l. In the meantime in Korea several further AB-process treatment plants were constructed, the overall planning and constructing period being not longer than one year.

Feasibility of the membrane bioreactor process for water reclamation

2001 ◽  
Vol 43 (10) ◽  
pp. 203-209 ◽  
Author(s):  
S. Adham ◽  
P. Gagliardo ◽  
L. Boulos ◽  
J. Oppenheimer ◽  
R. Trussell
Keyword(s):  
Literature Review ◽  
Activated Sludge ◽  
Membrane Bioreactor ◽  
Cost Evaluation ◽  
Water Reclamation ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
In Series ◽  
Volumetric Loading ◽  
Conventional Activated Sludge Process

The feasibility of the membrane bioreactor (MBR) process for water reclamation was studied. Process evaluation was based on the following: literature review of MBRs, worldwide survey of MBRs, and preliminary costs estimates. The literature review and the survey have shown that the MBR process offers several benefits over the conventional activated sludge process, including: smaller space and reactor requirements, better effluent water quality, disinfection, increased volumetric loading, and less sludge production. The MBR process can exist in two different configurations, one with the low-pressure membrane modules replacing the clarifier downstream the bioreactor (in series), and the second with the membranes submerged within the bioreactor. Four major companies are currently marketing MBRs while many other companies are also in the process of developing new MBRs. The MBR process operates in a considerably different range of parameters than the conventional activated sludge process. The preliminary cost evaluation has shown that the MBR process is cost competitive with other conventional wastewater treatment processes.

Effect of Supplemental Carbon Source on Phosphate Removal in an Alternating Activated Sludge Process

1993 ◽  
Vol 28 (11-12) ◽  
pp. 499-512 ◽  
Author(s):  
S. H. Isaacs ◽  
M. Henze ◽  
H. Søeberg ◽  
M. Kümmel
Keyword(s):  
Carbon Source ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Pilot Plant ◽  
Phosphate Uptake ◽  
Phosphate Removal ◽  
Activated Sludge Process ◽  
Significant Release

Pilot plant studies indicate that the addition of COD in the form of acetate to an alternating nutrient removal activated sludge process as a means to improve denitrification rates is not detrimental to biological phosphate removal. This is in spite of the fact that the added acetate can cause a significant release of phosphate during the anoxic phases in the aeration tanks. The added COD also appears to result in increased rates of aerobic phosphate uptake, thus improving the phosphate removal ability of the process. These observations are presented and discussed in the paper.

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