Optimized nutrient removal from wastewater
AssigneeAmerican Water Works Company, Inc.
InventorsEugenio Giraldo, Yanjin Liu, Swarna Muthukrishnan
Life of this patent
Estimating the term…
Abstract
Methods and systems are provided for reducing ammonia partially by a denitrification process. A stream containing ammonia is contacted with oxygen to form a first product stream in low dissolved oxygen conditions. The ratio of oxygen to nitrogen is about 2.28 g O2/g N—NH3 (2.28 grams of oxygen per gram of nitrogen in ammonia) or less. The first product stream is then exposed to organic matter in an amount of 0.57 g COD/g N—NH3 (0.57 grams of chemical oxygen demand per gram of nitrogen in ammonia). This microbial reaction ultimately produces nitrogen gas, water, and carbon dioxide.
Claims20
A method for reducing ammonia in a stream, the method comprising:
- providing a stream containing ammonia;
- contacting the ammonia-containing stream with an oxygen-containing stream under effective treatment conditions to form a first product stream, the ratio of ammonia in the ammonia-containing stream to oxygen in the oxygen-containing stream being about 2.28 g O2/g N—NH3 (2.28 grams of oxygen per gram of nitrogen in ammonia) or less;
- and
- exposing the first product stream to organic matter under effective treatment conditions in a ratio of about 0.57 g COD/g N—NH3 (0.57 grams of chemical oxygen demand per gram of nitrogen in ammonia) or less such that ammonia reduction occurs, wherein a mixed liquor is formed.
A method for reducing ammonia in a stream, the method comprising:
- in a tank, treating an influent stream containing ammonia with oxygen in an amount of 2.28 g O2/g N—NH3 (2.28 grams of oxygen per gram of nitrogen in ammonia) or less, the ammonia reacting with the oxygen to form a first product stream that includes nitrogen gas, nitrous acid, and water;
- in the tank, maintaining microaerophilic conditions to promote development of a microbial population;
- and
- exposing the first product stream to organic matter in a ratio of 0.57 g COD/g N—NH3 (0.57 grams of chemical oxygen demand per gram of nitrogen in ammonia) or less, the organic matter reacting with the nitrous acid to form a second product stream that includes nitrogen gas, water, and carbon dioxide.
A method for reducing ammonia in a stream, the method comprising:
- providing an influent stream having ammonia;
- flowing the influent stream to a tank that operates under effective treatment conditions to effectuate denitrification, the effective treatment conditions including a presence of a low level of dissolved oxygen;
- and
- in the presence of microorganisms, reacting the influent stream in the tank with oxygen in an amount of 2.28 g O2/g N—NH3 (2.28 grams of oxygen per gram of nitrogen in ammonia) or less and organic matter in an amount of 0.57 g COD/g N—NH3 (0.57 grams of chemical oxygen demand per gram of nitrogen in ammonia) or less such that the ammonia is converted to nitrogen gas, water, and carbon dioxide.
Dependencies are inferred from the claim text.