REDUCING THE EFFECTS OF HYSTERESIS IN A REACTOR OF THREE PHASES WITH PNEUMATIC TRANSPORT LOOP, IS... more REDUCING THE EFFECTS OF HYSTERESIS IN A REACTOR OF THREE PHASES WITH PNEUMATIC TRANSPORT LOOP, IS MADE WITH A WAND FOR SOLID IN SUSPENSION.LAS flow rates, GAS OR LIQUID TO GENERATE A SUSPENSION OF SOLID FULL, SON significantly higher than the flow rates necessary to maintain hysteresis effects ESTADO.ESTOS THAT cAN BE REDUCED sIGNIFICANTLY AND OBTAIN A SUBSTANTIAL energy reduction required to achieve the sleep state. SE USA, preferably a tube, CONTAINING OPENINGS THROUGH WHICH TAKES PLACE AN EXTRA CIRCULATION especially during the startup phase
For design purposes a simple model to predict the hydrodynamic behaviour of a three-phase interna... more For design purposes a simple model to predict the hydrodynamic behaviour of a three-phase internal airlift reactor is developed. The model predicts liquid circulation, gas hold-up and minimum gas supply rates for solids suspension. The reactor type considered has an internal riser and is not equipped with a gas disengagement area, resulting in a high downcomer gas flow rate. Its
A newly discovered process by which ammonium is converted to dinitrogen gas under anaerobic condi... more A newly discovered process by which ammonium is converted to dinitrogen gas under anaerobic conditions (the Anammox process) has now been examined in detail. In order to confirm the biological nature of this process, anaerobic batch culture experiments were used. All of the ammonium provided in the medium was oxidized within 9 days. In control experiments with autoclaved or raw wastewater, without added sludge or with added sterilized (either autoclaved or gamma irradiated) sludge, no changes in the ammonium and nitrate concentrations were observed. Chemical reactions could therefore not be responsible for the ammonium conversion. The addition of chloramphenicol, ampicillin, 2,4-dinitrophenol, carbonyl cyanide m-chlorophenylhydrazone (CCCP), and mercuric chloride (Hg II Cl2) completely inhibited the activity of the ammoniumoxidizing sludge. Furthermore, the rate of ammonium oxidation was proportional to the initial amount of sludge used. It was therefore concluded that anaerobic amm...
A newly discovered process by which ammonium is converted to dinitrogen gas under anaerobic condi... more A newly discovered process by which ammonium is converted to dinitrogen gas under anaerobic conditions (the Anammox process) has now been examined in detail. In order to confirm the biological nature of this process, anaerobic batch culture experiments were used. All of the ammonium provided in the medium was oxidized within 9 days. In control experiments with autoclaved or raw wastewater, without added sludge or with added sterilized (either autoclaved or gamma irradiated) sludge, no changes in the ammonium and nitrate concentrations were observed. Chemical reactions could therefore not be responsible for the ammonium conversion. The addition of chloramphenicol, ampicillin, 2,4-dinitrophenol, carbonyl cyanide m-chlorophenyl-hydrazone (CCCP), and mercuric chloride (HgIICl2) completely inhibited the activity of the ammonium-oxidizing sludge. Furthermore, the rate of ammonium oxidation was proportional to the initial amount of sludge used. It was therefore concluded that anaerobic amm...
The recently proposed DEAMOX (DEnitrifying AMmonium OXidation) process combines the anammox react... more The recently proposed DEAMOX (DEnitrifying AMmonium OXidation) process combines the anammox reaction with autotrophic denitrifying conditions using sulphide as an electron donor for the production of nitrite from nitrate within an anaerobic biofilm. This paper firstly presents a feasibility study of the DEAMOX process using synthetic (ammonia + nitrate) wastewater where sulphide is replaced by volatile fatty acids (VFA) as a more widespread electron donor for partial denitrification. Under the influent N-NH+4/N-NO3(-) and COD/N-NO3(-) ratios of 1 and 2.3, respectively, the typical efficiencies of ammonia removal were around 40% (no matter whether a VFA mixture or only acetate were used) for nitrogen loading rates (NLR) up to 1236 mg N/l/d. This parameter increased to 80% by increasing the influent COD/N-NO3(-) ratio to 3.48 and decreasing the influent N-NH4 +/N-NO3(-) ratio to 0.29. As a result, the total nitrogen removal increased to 95%. The proposed process was further tested with typical strong nitrogenous effluent such as reject water (total N, 530-566 mg N/l; total COD, 1530-1780 mg/l) after thermophilic sludge anaerobic digestion. For this, the raw wastewater was split and partially ( approximately 50%) fed to a nitrifying reactor (to generate nitrate) and the remaining part ( approximately 50%) was directed to the DEAMOX reactor where this stream was mixed with the nitrified effluent. Stable process performance up to NLR of 1,243 mg N/l/d in the DEAMOX reactor was achieved resulting in 40, 100, and 66% removal of ammonia, NOx(-), and total nitrogen, respectively.
REDUCING THE EFFECTS OF HYSTERESIS IN A REACTOR OF THREE PHASES WITH PNEUMATIC TRANSPORT LOOP, IS... more REDUCING THE EFFECTS OF HYSTERESIS IN A REACTOR OF THREE PHASES WITH PNEUMATIC TRANSPORT LOOP, IS MADE WITH A WAND FOR SOLID IN SUSPENSION.LAS flow rates, GAS OR LIQUID TO GENERATE A SUSPENSION OF SOLID FULL, SON significantly higher than the flow rates necessary to maintain hysteresis effects ESTADO.ESTOS THAT cAN BE REDUCED sIGNIFICANTLY AND OBTAIN A SUBSTANTIAL energy reduction required to achieve the sleep state. SE USA, preferably a tube, CONTAINING OPENINGS THROUGH WHICH TAKES PLACE AN EXTRA CIRCULATION especially during the startup phase
For design purposes a simple model to predict the hydrodynamic behaviour of a three-phase interna... more For design purposes a simple model to predict the hydrodynamic behaviour of a three-phase internal airlift reactor is developed. The model predicts liquid circulation, gas hold-up and minimum gas supply rates for solids suspension. The reactor type considered has an internal riser and is not equipped with a gas disengagement area, resulting in a high downcomer gas flow rate. Its
A newly discovered process by which ammonium is converted to dinitrogen gas under anaerobic condi... more A newly discovered process by which ammonium is converted to dinitrogen gas under anaerobic conditions (the Anammox process) has now been examined in detail. In order to confirm the biological nature of this process, anaerobic batch culture experiments were used. All of the ammonium provided in the medium was oxidized within 9 days. In control experiments with autoclaved or raw wastewater, without added sludge or with added sterilized (either autoclaved or gamma irradiated) sludge, no changes in the ammonium and nitrate concentrations were observed. Chemical reactions could therefore not be responsible for the ammonium conversion. The addition of chloramphenicol, ampicillin, 2,4-dinitrophenol, carbonyl cyanide m-chlorophenylhydrazone (CCCP), and mercuric chloride (Hg II Cl2) completely inhibited the activity of the ammoniumoxidizing sludge. Furthermore, the rate of ammonium oxidation was proportional to the initial amount of sludge used. It was therefore concluded that anaerobic amm...
A newly discovered process by which ammonium is converted to dinitrogen gas under anaerobic condi... more A newly discovered process by which ammonium is converted to dinitrogen gas under anaerobic conditions (the Anammox process) has now been examined in detail. In order to confirm the biological nature of this process, anaerobic batch culture experiments were used. All of the ammonium provided in the medium was oxidized within 9 days. In control experiments with autoclaved or raw wastewater, without added sludge or with added sterilized (either autoclaved or gamma irradiated) sludge, no changes in the ammonium and nitrate concentrations were observed. Chemical reactions could therefore not be responsible for the ammonium conversion. The addition of chloramphenicol, ampicillin, 2,4-dinitrophenol, carbonyl cyanide m-chlorophenyl-hydrazone (CCCP), and mercuric chloride (HgIICl2) completely inhibited the activity of the ammonium-oxidizing sludge. Furthermore, the rate of ammonium oxidation was proportional to the initial amount of sludge used. It was therefore concluded that anaerobic amm...
The recently proposed DEAMOX (DEnitrifying AMmonium OXidation) process combines the anammox react... more The recently proposed DEAMOX (DEnitrifying AMmonium OXidation) process combines the anammox reaction with autotrophic denitrifying conditions using sulphide as an electron donor for the production of nitrite from nitrate within an anaerobic biofilm. This paper firstly presents a feasibility study of the DEAMOX process using synthetic (ammonia + nitrate) wastewater where sulphide is replaced by volatile fatty acids (VFA) as a more widespread electron donor for partial denitrification. Under the influent N-NH+4/N-NO3(-) and COD/N-NO3(-) ratios of 1 and 2.3, respectively, the typical efficiencies of ammonia removal were around 40% (no matter whether a VFA mixture or only acetate were used) for nitrogen loading rates (NLR) up to 1236 mg N/l/d. This parameter increased to 80% by increasing the influent COD/N-NO3(-) ratio to 3.48 and decreasing the influent N-NH4 +/N-NO3(-) ratio to 0.29. As a result, the total nitrogen removal increased to 95%. The proposed process was further tested with typical strong nitrogenous effluent such as reject water (total N, 530-566 mg N/l; total COD, 1530-1780 mg/l) after thermophilic sludge anaerobic digestion. For this, the raw wastewater was split and partially ( approximately 50%) fed to a nitrifying reactor (to generate nitrate) and the remaining part ( approximately 50%) was directed to the DEAMOX reactor where this stream was mixed with the nitrified effluent. Stable process performance up to NLR of 1,243 mg N/l/d in the DEAMOX reactor was achieved resulting in 40, 100, and 66% removal of ammonia, NOx(-), and total nitrogen, respectively.
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Papers by Arnold Mulder