Examples for the Upgrading of Existing Activated Sludge Plants for Nutrient Removal

1990 ◽  
Vol 22 (7-8) ◽  
pp. 113-121
Author(s):  
W. Maier
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Sewage Treatment ◽  
West Germany ◽  
Sewage Treatment Plants ◽  
Effluent Standards ◽  
Near Future

In view of the new effluent standards in West Germany, including nitrification and phosphorus elimination, many of the existing sewage treatment plants will have to be rebuilt or expanded. Another demand which will have to be dealt with in the near future is denitrification. Under consideration of the large BOD5-loads which were taken into account when designing the plants, many of them nitrify during the summer or can be easily converted to operate with nitrification. Principles for planning the upgrading of such plants have been laid down in order to achieve the required effluent concentrations. The application of these principles is demonstrated with examples of upgraded plants.

Optimization of Nutrient Removal in Stockholm

1991 ◽  
Vol 24 (7) ◽  
pp. 103-111 ◽  
Author(s):  
G. Brattberg ◽  
L.-G. Reinius ◽  
M. Tendaj
Keyword(s):  
Nutrient Removal ◽  
Sewage Treatment ◽  
Water Source ◽  
Chemical Precipitation ◽  
Phosphorus Load ◽  
Sewage Treatment Plants ◽  
Limiting Nutrient ◽  
Baltic Proper ◽  
Mechanical Stage ◽  
The Baltic

Stockholm was founded at the point where the waters of Lake Mälaren emerge into the Baltic Sea. Lake Mälaren is the water source of the water works of Stockholm. The Lake also receives water from one of the sewage treatment plants. The outlet from the two other sewage treatment plants are in the inner part of the archipelago. During 1968-73 the treatment was improved, after which the phosphorus load to the receiving water significantly decreased. The total P concentration in the surface water has decreased since 1970 and phosphorus has replaced nitrogen as the most limiting nutrient throughout the entire archipelago within 50 km from Stockholm. To further reduce the eutrophication a continued reduction of the phosphorus load is most effective. For the Baltic proper as a whole, where primary nitrogen limitation is present, it is important to reduce the supply of nitrogen to the greatest possible extent. The treatment plants in Stockholm are located in subsurface rock-chambers. The treatment includes mechanical, biological and chemical treatment. In the mechanical stage the sewage is treated in screens, grit chambers and primary sedimentation. The biological stage is a conventional activated sludgeprocess. For the chemical precipitation ferroussulphateis added before the screens. The sludge is stabilized in anaerobic digesters and dewatered in centrifuges before disposal on farmland. To meet more stringent requirements on nitrification and nitrogen removal several projects are going on to optimize the nutrient removal. The aim of these investigations is to improve the plants' performance within the existing plant.

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.

Removal Efficiencies of Indicator Micro-Organisms in Sewage Treatment Plants

1989 ◽  
Vol 21 (3) ◽  
pp. 119-124 ◽  
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.

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

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.

Influence of microbial activity on polar xenobiotic degradation in activated sludge systems

2010 ◽  
Vol 62 (3) ◽  
pp. 701-707 ◽  
Author(s):  
M. Majewsky ◽  
T. Gallé ◽  
L. Zwank ◽  
K. Fischer
Keyword(s):  
Activated Sludge ◽  
Microbial Activity ◽  
Suspended Solids ◽  
Sewage Treatment ◽  
Total Suspended Solids ◽  
Active Biomass ◽  
Sewage Treatment Plants ◽  
Degradation Rates ◽  
Xenobiotic Degradation ◽  
Activated Sludge Systems

The influence of activated sludge quality on the co-metabolic biodegradation of three aminopolycarboxyl acids was investigated for a variety of Luxembourg sewage treatment plants. A combination of biodegradation experiments and respirometric techniques are presented as a reliable approach for the estimation of biokinetics and biological xenobiotic degradation rates that allow for identification of governing parameters such as microbial activity and active biomass. Results showed that biokinetics and degradation rates vary greatly between different plants. The fraction of active biomass on the total suspended solids ranged between 16.9 and 53.7%. Xenobiotic biodegradation rates correlated with microbial activity suggesting a relationship with WWTP performance for carbon and nutrient removal. The biokinetic information can be used to increase the prediction accuracy of xenobiotics removal by individual WWTPs.

Sewage-treatment under substantial load variations in winter tourism areas – a full case study

2004 ◽  
Vol 50 (7) ◽  
pp. 147-155 ◽  
Author(s):  
S. Winkler ◽  
N. Natsché ◽  
T. Gamperer ◽  
M. Dum
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Nutrient Removal ◽  
Sewage Treatment ◽  
Activated Sludge Process ◽  
Two Stage ◽  
Winter Tourism ◽  
Load Variations ◽  
Sudden Load

The sewage-load variations in winter tourism areas are characterized by sudden increases - in the ange of a factor two to three - within only a few days at the start and the end of the tourist season, especially at Christmas. The sudden load increases occur during periods of low wastewater temperatures, which is an additional demanding factor with respect to nitrogen removal. A full case study was carried out at WWTP Saalfelden, which is located near one of Austria's largest skiing resorts. The plant is designed for 80,000 PE and built according to the HYBRID®-concept, which is a special two stage activated sludge process for extensive nutrient removal.

scholarly journals Fermentation of plant residues to produce biogas

2020 ◽  
Vol 161 ◽  
pp. 01113
Author(s):  
Yulia Smyatskay ◽  
Natalia Politaeva ◽  
Irina Atamanyk ◽  
Daria Sobgaida
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Test System ◽  
Chlorella Sorokiniana ◽  
Methane Content ◽  
Plant Residues ◽  
Sewage Treatment Plants ◽  
Valuable Source ◽  
Digestion Process ◽  
Residual Biomass

In this paper, we consider the process of producing biogas with a high methane content when used as a co-substrate for fermentation of plant residues of microalgae. Microalgae Chlorella sorokiniana are a valuable source for obtaining valuable components such as lipids, pigments, proteins, chlorophyll and others. After the extraction of valuable components, residual biomass is formed, which requires further disposal. In this experiment, the digestion process is carried out using an inoculant — lyophilically dried activated sludge from sewage treatment plants in Hamburg in the amount of 450 ml and residual biomass of the microalga Chlorella sorokiniana in the amount of 2.1 g. The studies were carried out in the Anaerobes Test system AMPT-II system. Fermentation produces 205 ml of methane gas.

Possibilities for increased nutrient removal with a final filtration stage

1996 ◽  
Vol 33 (12) ◽  
pp. 147-153
Author(s):  
M. Rothman ◽  
J. Hultgren
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Nutrient Removal ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
High Concentrations ◽  
Winter Time ◽  
Filtration Stage

Bromma sewage treatment plant (STP) is one of three plants in Stockholm. To meet more stringent requirements for nutrient removal the plant has been extended with a final filtration stage. Earlier it has not been possible to operate the plant with nitrification during winter time. Bad settling properties of the activated sludge have led to bulking sludge and high concentrations of BOD and phosphorus in the effluent. With the filter stage it is now possible to reduce the load on the biological stage by by-passing part of the flow directly to the filters. The result has been very promising and it seems that the plant can meet the new demands for nitrogen removal without extension of the aerated volumes.

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