Trickling filters for upgrading low technology wastewater plants for nitrogen removal

2004 ◽  
Vol 49 (11-12) ◽  
pp. 47-52 ◽  
Author(s):  
P. Pearce
Keyword(s):  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Original Data ◽  
Significant Degree ◽  
Primary Treatment ◽  
Trickling Filter ◽  
Trickling Filters ◽  
Water Region ◽  
Filter Process ◽  
The Uk

Previous work through the 1990s in the Thames Water region in the UK has demonstrated the ability of the trickling filter process to produce fully nitrified effluents, reliably throughout the year. The original data used for the nitrification model derivations have been reanalysed, to investigate the degree of nitrogen removal across the process. Removals of total nitrogen ranging from 0% to over 50% were observed across the trickling filter process and calculated total nitrogen removals of 26-63% were obtained when primary treatment was included. The degree of nitrogen removal and biological denitrification (excluding cellular assimilation) was found to be strongly influenced by BOD load, irrigation velocity and media size. Regression models were produced which gave good predictive relationships for the data ranges used. The models produced worked for filters used with and without a recirculation of effluent nitrate which suggests that a significant degree of nitrification occurred in areas of high heterotroph activity (BOD removal). The simplicity and energy efficiency of the trickling filter process, combined with its capacity for full nitrification and partial denitrification, make the process attractive as a combined process used with pond systems in developing countries where nitrogen removal may be required. Some of these synergies have already been developed with the PETRO® process in South Africa.

Denitrification in trickling filters

1994 ◽  
Vol 30 (6) ◽  
pp. 181-184 ◽  
Author(s):  
Bernd Dorias ◽  
Peter Baumann
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Capital Expenditure ◽  
Sewage Treatment ◽  
Innovative Technology ◽  
Activated Sludge Process ◽  
Trickling Filter ◽  
Sewage Treatment Plants ◽  
Trickling Filters ◽  
Test Operation

National and international regulations require a minimum nitrogen removal efficiency of 70% in most public sewage treatment plants. Unlike in activated sludge plants, selective denitrification in trickling filters was not possible until now. Therefore the aim was to employ trickling filter plants for selective denitrification, using innovative technology that involved minimum capital expenditure. For selective denitrification, it is necessary to prevent as much as possible the transfer of oxygen into the trickling filter while feeding the nitrate to be removed, a process similar to upstream denitrification in the activated sludge process. In a test operation conducted in several sewage treatment plants for over a year, the new process with selective denitrification in a covered trickling filter has given successful results. The denitrification efficiency of this system is comparable to that of upstream denitrification in the activated sludge process. Thus, selective denitrification in the trickling filter is a practical alternative to other nitrogen removal processes, while maintaining the established advantages offered by the trickling filter process.

Upgrading for nitrogen removal under severe site restrictions

1998 ◽  
Vol 37 (9) ◽  
pp. 185-192 ◽  
Author(s):  
P. Balmér ◽  
L. Ekfjorden ◽  
D. Lumley ◽  
A. Mattsson
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Plant Design ◽  
Trickling Filter ◽  
Process Selection ◽  
Trickling Filters ◽  
Plant Area ◽  
Highly Loaded

The Rya WWTP in Göteborg, Sweden is a highly loaded activated sludge plant which has been upgraded to remove nitrogen and to increase the biologically treated flow by 33% to reduce bypassing. Severe site restrictions made it difficult to increase the plant area. This was solved using a compant process based on tertiary nitrification in trickling filters and recirculation to a highly loaded activated sludge unit for denitrification. The necessary volumes were achieved by expanding the plant upwards, thus making it possible to place the trickling filters a in part of the area occupied by the former aeration basins. The recirculation of trickling filter effluent made it necessary to double the secondary settler capacity. This was solved by retrofitting the existing settlers as stacked settlers with a second tray on top of the original basin. The considerations behind process selection and plant design and costs are described.

scholarly journals Nitrogen Removal in a Full-Scale Domestic Wastewater Treatment Plant with Activated Sludge and Trickling Filter

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Davood Nourmohammadi ◽  
Mir-Bager Esmaeeli ◽  
Hossein Akbarian ◽  
Mohammad Ghasemian
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Treated Wastewater ◽  
Trickling Filter ◽  
High Concentration ◽  
Nitrogen Gas

During the last decade, more stringent effluent requirements concerning the nutrients effluent values have been imposed by legislation and social concern. In this study, efficiency of total nitrogen removal in activated sludge and trickling filter processes (AS/TF) was investigated in Tehran North wastewater treatment plant. Biological system in this site was included, anoxic selector tank, aeration tank, final sedimentation, and trickling filter. A part of treated wastewater before chlorination was mixed with supernatant of dewatered sludge and fed to the trickling filter. Supernatant of dewatered sludge with high concentration of NH4-N was diluted by treated wastewater to provide complete nitrification in trickling filter Produced nitrate in trickling filter was arrived to the anoxic tank and converted to nitrogen gas by denitrification. According to the study result, low concentration of organic carbone and high concentration of NH4-N led to nitrification in TF, then nitrate denitrification to nitrogen gas occurred in selector area. NH4-N concentration decreased from 26.8 mg/L to 0.29 mg/L in TF, and NO3-N concentration increased from 8.8 mg/L to 27 mg/L in TF. Consequently, the total nitrogen decreased approximately to 50% in biological process. This efficiency has been observed in returned flow around 24% from final sedimentation into TF. It was concluded that, in comparison with biological nutrient removal processes, this process is very efficient and simple.

Rehabilitation and Upgrading of the Beni Suef City Wastewater Treatment Plant

1990 ◽  
Vol 22 (7-8) ◽  
pp. 131-138
Author(s):  
Ahmed Fadel
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Primary Treatment ◽  
High Rate ◽  
Shock Load ◽  
Economic Evaluations ◽  
Activated Sludge Process ◽  
Trickling Filter

Many of Egypt's cities have existing treatment plants under operation that have been constructed before 1970. Almost all of these treatment plants now need rehabilitation and upgrading to extend their services for a longer period. One of these plants is the Beni Suef City Wastewater Treatment Plant. The Beni Suef WWTP was constructed in 1956. It has primary treatment followed by secondary treatment employing intermediate rate trickling filters. The BOD, COD, and SS concentration levels are relatively high. They are approximately 800, 1100, and 600 mg/litre, respectively. The Beni Suef city required the determination of the level of work needed for the rehabilitation and upgrading of the existing 200 l/s plant and to extend its capacity to 440 l/s at year 2000 A description of the existing units, their deficiencies and operation problems, and the required rehabilitation are presented and discussed in this paper. Major problems facing the upgrading were the lack of space for expansion and the shortage of funds. It was, therefore, necessary to study several alternative solutions and methods of treatment. The choice of alternatives was from one of the following schemes: a) changing the filter medium, its mode of operation and increasing the number of units, b) changing the trickling filter to high rate and combining it with the activated sludge process, for operation by one of several possible combinations such as: trickling filter-solids contact, roughing filter-activated sludge, and trickling filter-activated sludge process, c) dividing the flow into two parts, the first part to be treated using the existing system and the second part to be treated by activated sludge process, and d) expanding the existing system by increasing the numbers of the different process units. The selection of the alternative was based on technical, operational and economic evaluations. The different alternatives were compared on the basis of system costs, shock load handling, treatment plant operation and predicted effluent quality. The flow schemes for the alternatives are presented. The methodology of selecting the best alternative is discussed. From the study it was concluded that the first alternative is the most reliable from the point of view of costs, handling shock load, and operation.

Operational Results of the Wolfsburg Wastewater Treatment Plant

1992 ◽  
Vol 25 (4-5) ◽  
pp. 203-209 ◽  
Author(s):  
R. Kayser ◽  
G. Stobbe ◽  
M. Werner
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nitrogen Content ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Phosphate Removal ◽  
Total Nitrogen Content ◽  
Activated Sludge Process

At Wolfsburg for a load of 100,000 p.e., the step-feed activated sludge process for nitrogen removal is successfully in operation. Due to the high denitrification potential (BOD:TKN = 5:1) the effluent total nitrogen content can be kept below 10 mg l−1 N; furthermore by some enhanced biological phosphate removal about 80% phosphorus may be removed without any chemicals.

Biological removal of algae in an integrated pond system

1995 ◽  
Vol 31 (12) ◽  
pp. 21-31 ◽  
Author(s):  
P. G. J. Meiring ◽  
R. A. Oellermann
Keyword(s):  
Adsorptive Capacity ◽  
Trickling Filter ◽  
Laboratory Findings ◽  
Oxidation Pond ◽  
Trickling Filters ◽  
Biological Removal ◽  
In Series ◽  
The Media ◽  
Oxidation Ponds ◽  
Dark Green

A system of oxidation ponds in series with a biological trickling filter is described. It was known that this arrangement was incapable of reducing effectively the levels of algae present in the pond liquid even though nitrification was effected because of autotrophic conditions prevailing in the trickling filters. This very low trophic level explained the lack of adsorptive capacity present. By shortcircuiting less than 10 percent of the effluent from a fully loaded primary facultative oxidation pond to the trickling filter, the autotrophuc nature or the film in the trickling filter was sufficiently shifted towards a heterotrophic state that had sufficient adsorptive capacity to retain the majority of the algae. It is concluded that the algae, although being absorbed, stay alive on the film and do not contribute significantly to the carbonaceous load on the trickling filter. Further more the algae, although secluded from all sunlight, actually partake in the purification process, producing an effluent which, unlike a normal humus tank effluent, is surprisingly sparkling clear. This significant observation appears to be in line with laboratory findings by others who, when they artificially immobilised certain species of algae and passed water over them, concluded that the algae retained the potential to remove certain compounds from the water. Conglomerates of biologically flocculated dark-green algae are scoured off the film (or sloughed off as part of the film) and, having been photosynthetically inactive for some days, tend not to float, but settle very rapidly. A very significantly aspect of this development is the great potential it has for practical application in developing countries. The algae sloughed off the media are easily thickened and available for ultimate recovery from the water phase without the addition of chemicals.

Heating up trickling filters to tackle cold weather conditions

2000 ◽  
Vol 41 (1) ◽  
pp. 163-166 ◽  
Author(s):  
W. Gebert ◽  
P.A. Wilderer
Keyword(s):  
Waste Heat ◽  
Treatment Plant ◽  
Weather Conditions ◽  
Pilot Scale ◽  
Cold Weather ◽  
Filling Material ◽  
Trickling Filter ◽  
Biofilm Thickness ◽  
Trickling Filters ◽  
Biofilm Support

The investigated effects of heating the filling material in trickling filters were carried out at the Ingolstadt wastewater treatment plant, Germany. Two pilot scale trickling filters were set up. Heat exchanger pipings were embedded in the filter media of one of these trickling filters, and the temperature in the trickling filter was raised. The other trickling filter was operated under normal temperature conditions, and was used as a control. The results clearly demonstrate that the performance of trickling filters cannot be constantly improved by heating the biofilm support media. A sustained increase of the metabolic rates did not occur. The decrease of the solubility of oxgen in water and mass transfer limitations caused by an increase of the biofilm thickness are the main reasons for that. Thus, the heating of trickling filters (e.g. by waste heat utilization) in order to increase the capacity of trickling filters under cold weather conditions cannot be recommended.

Dynamic simulation of a low loaded trickling filter for nitrification

1999 ◽  
Vol 39 (4) ◽  
pp. 163-168 ◽  
Author(s):  
K. Seggelke ◽  
F. Obenaus ◽  
K.-H. Rosenwinkel
Keyword(s):  
Dynamic Simulation ◽  
Weather Conditions ◽  
Full Scale ◽  
Trickling Filter ◽  
Examination Period ◽  
Trickling Filters ◽  
Biofilm Model ◽  
Measuring Campaign

For this report, an existing biofilm model was examined in regard to its suitability for the simulation of full scale trickling filter for nitrification. The system was calibrated using the results ascertained in a measuring campaign under dry weather conditions. The verification was done using the results of a second examination period which included spells of stormwater input. It was possible for all periods to satisfactorily illustrate the degradation performance of the simulated trickling filters in regard to dynamics and quantity.

scholarly journals Time-to-Treatment in Oral Cancer: Causes and Implications for Survival

Cancers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1321
Author(s):  
Constanza Saka-Herrán ◽  
Enric Jané-Salas ◽  
Antoni Mari-Roig ◽  
Albert Estrugo-Devesa ◽  
José López-López
Keyword(s):  
Oral Cancer ◽  
Previous Treatment ◽  
Diagnostic Procedures ◽  
Original Data ◽  
Primary Treatment ◽  
Medical Attention ◽  
Time Interval ◽  
Pre Treatment ◽  
The Impact ◽  
Lack Of Knowledge

The purpose of this review was to identify and describe the causes that influence the time-intervals in the pathway of diagnosis and treatment of oral cancer and to assess its impact on prognosis and survival. The review was structured according to the recommendations of the Aarhus statement, considering original data from individual studies and systematic reviews that reported outcomes related to the patient, diagnostic and pre-treatment intervals. The patient interval is the major contributor to the total time-interval. Unawareness of signs and/or symptoms, denial and lack of knowledge about oral cancer are the major contributors to the process of seeking medical attention. The diagnostic interval is influenced by tumor factors, delays in referral due to higher number of consultations and previous treatment with different medicines or dental procedures and by professional factors such as experience and lack of knowledge related to the disease and diagnostic procedures. Patients with advanced stage disease, primary treatment with radiotherapy, treatment at an academic facility and transitions in care are associated with prolonged pre-treatment intervals. An emerging body of evidence supports the impact of prolonged pre-treatment and treatment intervals with poorer survival from oral cancer.

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