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| 2. |
- Plaza, Elzbieta, et al.
(författare)
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Impact of seeding with nitrifying bacteria on nitrification process efficiency
- 2001
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 43:1, s. 155-163
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Tidskriftsartikel (refereegranskat)abstract
- Seeding of nitrifying bacteria into the activated sludge process was studied both theoretically and experimentally. A simple model was developed for prediction of the effects of seeding of nitrifying bacteria from a separate stage into the activated sludge process. The purpose of seeding is to improve the treatment results and the process stability as well as to decrease the volume requirements of the process. Pilot plant studies were carried out at the Uppsala municipal wastewater treatment plant in order to evaluate the effects of seeding. One line was supplied with supernatant from dewatering of digested sludge and the nitrification process gave an activated sludge with a high fraction of nitrifying bacteria, suitable for seeding. The other line was supplied with pre-precipitated wastewater and with the excess sludge from the line treating the supernatant. The experimental results showed that nitrification could be obtained at sludge ages that would otherwise preclude nitrification. Performance relationships for the system developed, based on laboratory and on-line measurements were studied and are presented. The studies show that seeding may decrease the necessary volume needs for a stable nitrification process and that the effects could be predicted by use of a simple model.
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| 3. |
- Stypka, T., et al.
(författare)
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Regional planning and product recovery as tools for sustainable sludge management
- 2002
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 46:05-apr, s. 389-396
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Tidskriftsartikel (refereegranskat)abstract
- The article presents two aspects of sludge management: regional planning and product recovery. The introduction of these two elements can reduce the cost, close the ecocycle and make the management more sustainable. A spreadsheet program to optimize the regional location of different facilities is presented. The simple example shows the potential of the model. The brief comparison of formal problems concerning sludge disposal in Poland and Sweden is also discussed. Requirements of phosphorus recovery and recycling of phosphorus to the phosphate industry make sludge fractionation in combination with product recovery a new development in wastewater handling. Phosphorus recovery from sludges with chemical bound phosphorus requires complex and expensive process technology and may therefore lead to increased regional sludge management with a central sludge treatment plant.
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| 4. |
- Szatkowska, Beata, et al.
(författare)
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Influence of dissolved oxygen concentration on deammonification process performance
- 2004
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Ingår i: Integration and optimisation of urban sanitation systems. - 9172836644 ; , s. 121-131
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Partial nitrification together with Anammox process (deammonification) is a new method fornitrogen removal from wastewater, which nowadays is widely studied in Europe. Compared toconventional nitrification/denitrification, this method saves 100% of the required organic carbonsource and over 60% of the required oxygen. This leads to a reduction of operational costs of 90%.The deammonification process was successfully tested on a laboratory-scale pilot plant at RoyalInstitute of Technology (KTH) in Sweden for over 2 years. Two reactors of pilot plant were filledwith Kaldnes rings as a biofilm carrier and supplied with a supernatant from dewatering of thedigested sludge at the Bromma Wastewater Treatment Plant (WWTP). For the stable and efficientprocess performance a suitable values of many parameters as dissolved oxygen, pH, temperature,NO2-N and NO3-N concentration should be assured. This article presents an evaluation of theinfluence of dissolved oxygen (DO) on the deammonification process efficiency. Analysis of eightmonths operation of pilot plant proved that high N-removal efficiency of second reactor (Anammox)is assured by proper NO2-N/NH4-N ratio in the effluent from the first reactor depending on DOconcentration. To estimate influence of DO concentration on reaction rates during the Anammoxprocess several batch tests were performed. The highest ammonium and nitrite removal rates wereobtained for DO concentration amounted to 0.2÷0.4 mg O2/l. This is in agreement with theobservations from laboratory-scale pilot plant, when the best results for Anammox processefficiency took place under similar oxygen conditions. A linear correlation between inorganicnitrogen removal and conductivity in the batch tests proved that conductivity could be a suitableparameter for a nitrogen removal process control.
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| 5. |
- Szatkowska, Beata, et al.
(författare)
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Monitoring Of Nitrogen Removal Processes By Use Of Conductivity Measurements : [Övervakning av kvävereduktionsprocesser med hjälp av konduktivitetsmätningar]
- 2004
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Ingår i: Vatten. - 0042-2886. ; 60:2, s. 111-118
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Tidskriftsartikel (refereegranskat)abstract
- A newly developed technology for nitrogen removal from ammonium-rich streams comprises two biological steps. In the first step, about half of the ammonium is oxidized to nitrite (partial nitritation) and in the second one, the remaining ammonium reacts with the formed nitrite into nitrogen gas (Anammox; anaerobic ammonium oxidation). The system was studied in a laboratory-scale pilot plant at the Royal Institute of Technology (KTH) and in a pilot plant located at the Himmerfjärden Wastewater Treatment Plant (WWTP). Both plants were supplied with ammonium-rich supernatant from digested sludge dewatering. Kaldnes rings were used as biofilm carriers. The process performance was closely monitored by analysis of different nitrogen fractions, COD, alkalinity and measurements of pH, oxygen concentration and temperature. Additionally, conductivity measurements were performed. It was found that conductivity is an excellent method to monitor the nitrogen removal processes. Such observation is based on the fact that the supernatant main salt is ammonium hydrogen carbonate, which further during the processes is converted to the carbon dioxide and nitrogen gas molecules. Theoretically calculated conductivity values were in good agreement with the experimental data. Conductivity turns out to be a reliable and Inexpensive method to evaluate different biological nitrogen removal processes used for separate treatment of supernatant.
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| 7. |
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| 8. |
- Trela, Jozef, et al.
(författare)
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Deammonifikation Som En Ny Process För Behandling Av Avloppsströmmar Med Hög Kvävehalt : [Deammonification as a new process for treatment of wastewater with a high nitrogen content]
- 2004
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Ingår i: Vatten. - 0042-2886. ; 60:2, s. 119-127
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Pilot plant-scale experiments have been carried out to study a new technology for nitrogen removal from digester supernatant. The plant comprises two parallel lines, which now operate as a two-step process. Two pilot plant reactors (each volume of 2 m3) were filled with Kaldnes rings up to 50 % of their volume. In the First step of the process, half of the ammonium is oxidized to nitrite without further oxidation to nitrate (nitritation). Then the second step follows, where equal amounts of ammonium and nitrite reacts to form nitrogen gas (Anammox). The pilot plant is continuously fed with supernatant from digested sludge dewatering process at the Himmerfjärden WWTP. This type of wastewater has a high ammonium concentration and a low content of biodegradable organic matter.
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