Influence of integrated of activated sludge-trickling filter two-step and upflow suspended growth denitrification processes on the COD fractions in the municipal wastewaters

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.

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Trickling Filter and Trickling Filter–Suspended Growth Process Design and Operation: A State–of–the–Art Review

Water Environment Research ◽

10.2175/106143010x12681059117211 ◽

2011 ◽

Author(s):

Glen T. Daigger ◽

Joshua P. Boltz

Keyword(s):

Process Design ◽

Growth Process ◽

Trickling Filter ◽

Suspended Growth

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Trickling filter-activated sludge combinations for domestic wastewater treatment

10.31274/rtd-180813-4230 ◽

1972 ◽

Author(s):

Robert Frank Roskopf

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Domestic Wastewater ◽

Trickling Filter ◽

Domestic Wastewater Treatment

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The Olifantsfontein Nutrient Removal Plant

Water Science & Technology ◽

10.2166/wst.1990.0224 ◽

1990 ◽

Vol 22 (7-8) ◽

pp. 1-8 ◽

Cited By ~ 4

Author(s):

J. A. van Huyssteen ◽

J. L. Barnard ◽

J. Hendriksz

Keyword(s):

Mathematical Model ◽

Activated Sludge ◽

South African ◽

Nutrient Removal ◽

Trickling Filter ◽

The South ◽

The University ◽

General Standard

The paper describes the upgrading of an existing trickling filter (TF) plant by adding a new activated sludge (AS) plant in order to remove nutrients from the combined effluent of both plants. In spite of the low COD/TKN ratio, good nitrogen and phosphate removals were obtained in the three-stage Bardenpho (AS) plant. This is at variance with the University of Capetown mathematical model which predicted that nutrient removal in this plant would not be possible due to predicted recycle of nitrates to the anaerobic basin. The results showed that the average effluent phosphate was below 1 mg P/ℓ while the ammonia and nitrates could be controlled to values well below the limits of the South African General Standard. Possible reasons for the anomaly are given.

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Denitrification in trickling filters

Water Science & Technology ◽

10.2166/wst.1994.0267 ◽

1994 ◽

Vol 30 (6) ◽

pp. 181-184 ◽

Cited By ~ 2

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.

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Removal Efficiencies of Indicator Micro-Organisms in Sewage Treatment Plants

Water Science & Technology ◽

10.2166/wst.1989.0088 ◽

1989 ◽

Vol 21 (3) ◽

pp. 119-124 ◽

Cited By ~ 14

Author(s):

T. Omura ◽

M. Onuma ◽

J. Aizawa ◽

T. Umita ◽

T. Yagi

Keyword(s):

Activated Sludge ◽

Sewage Treatment ◽

High Rate ◽

Coliform Bacteria ◽

Minor Role ◽

Activated Sludge Process ◽

Trickling Filter ◽

Sewage Treatment Plants ◽

Micro Organisms ◽

Chlorine Residuals

The removal of coliform bacteria, enterococcus bacteria, and coliphages in two sewage treatment plants, one using the activated sludge process and the other using a high-rate trickling filter, was investigated over a period of one year. Coliform and enterococcus bacteria were removed with equal efficiency by the two plants, but coliphages were removed more efficiently by the activated sludge process. Experiments on the mechanism of removal revealed that it was mainly due to adsorption on the activated sludge and on the slime in the trickling filter. Die-off of the micro-organisms seemed to play a minor role in the reduction in counts. The treated sewage was disinfected by chlorination prior to discharge into the receiving water. No coliforms were detected in the chlorinated effluents when they had chlorine residuals in the range of 0 to 1.521 mg/l. However, enterococci were detected when chlorine residuals dropped below 0.598 mg/l. Coliphages proved to be the most resistant organisms and they were generally detected throughout the range of chlorine residuals encountered.

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Post-Denitrification with Controlled Feeding of Activated Sludge as H Donator

Water Science & Technology ◽

10.2166/wst.1990.0242 ◽

1990 ◽

Vol 22 (7-8) ◽

pp. 161-170

Author(s):

I. Sekoulov ◽

R. Addicks ◽

J. Oles

Keyword(s):

Activated Sludge ◽

Sewage Treatment ◽

Domestic Sewage ◽

Trickling Filter ◽

Sewage Treatment Plants ◽

Effluent Quality ◽

Second Stage ◽

Denitrification Reactor ◽

The Given ◽

Complicated Configuration

Enlargement and/or upgrading of already existing sewage treatment plants will bring problems to design and operation. However, this can be solved even in some complicated configuration of the treatment system, as will be demonstrated. Having an activated sludge system for BOD removal (first stage) followed by a trickling filter for nitrification (second stage), denitrification of the effluent without an external H donator is hard to achieve. In domestic sewage treatment, denitrification is usually carried out with BOD as carbon source. Additionally to the principal question of pre- or post denitrification and the related effects on the effluent quality (BOD, COD, NH4) pre-denitrification in the given case would be highly ineffective and uneconomical (large hydraulic loads). The paper presents a system using thickened sludge from the activated sludge sedimentation as H donator. The sludge has been successfully used to denitrify the trickling filter effluent. For the design of the post-denitrification stage, the necessary volume of sludge could be determined together with the volume of the denitrification reactor. Results of the pilot-plant studies are presented.

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Microbiological Aspects of the Treatment of Joint Oil Refinery and Municipal Wastewaters

Water Science & Technology ◽

10.2166/wst.1986.0084 ◽

1986 ◽

Vol 18 (9) ◽

pp. 115-123 ◽

Cited By ~ 2

Author(s):

O. Petrović ◽

B. Dalmacija ◽

D. Misković ◽

M. Gantar ◽

S. Gajin

Keyword(s):

Activated Carbon ◽

Activated Sludge ◽

Municipal Wastewater ◽

Direct Method ◽

Oil Refinery ◽

Coliform Bacteria ◽

Organic Load ◽

Microbiological Analysis ◽

Municipal Wastewaters ◽

Microbiological Treatment

The bacteriological parameters of both the primary and secondary microbiological treatment of mixed oil refinery and municipal wastewaters have here been analyzed. Primary treatment was performed using activated sludge in a two grade bioreactor and for the secondary treatment, four columns with granular activated carbon were used. The first and the last column were aerated, whereas the two in the middle were without aeration. The ratios of the oil refinery (R) to municipal (M) wastewaters in the mixtures were 85:15, 70:30, 50:50 and 30:70. The microbiological analyses included the total bacterial count (direct method), the number of heterotrophs and oligotrophs with their ratios, number of coliforms, nitrifying and denitrifying bacteria (growing method). Activated sludge as well as microbial community on the activated carbon were investigated by using scanning electron microscopy. Chemical parameters, such as pH, COD, BOD, NH4+, NO2− and NO3− were determined by the standard methods. The performed microbiological analysis approved the validity of the joint oil refinery and municipal wastewater treatment. The decrease of the organic load in purified water ranged from 88 to 96 % (COD estimate) and from 91 to 99 % (BOD estimate) while the removal of individual groups of microorganisms varied from 55 to 99 %. The highest decrease was observed in the coliform bacteria (97 - 99 %). It is worth noting that a decrease in the total nitrogen in the system ranged from 59 to 74 % and that of nitrate from 56 to 61 % after secondary microbiological treatment.

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