# US 5,702,572 A · Method for treating exhaust gases and foul water

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- Number: US 5,702,572 A
- Document ID: US5702572A
- Status: Granted
- Kind: A
- Application number: 08/757,736
- Filed: 1996-11-26
- Granted: 1997-12-30
- Earliest claimed: 1995-11-27
- Assignees: Ebara Corporation
- Inventors: Hiroyuki Fujimura; Takayuki Suzuki; Norio Yamada; Yoshiyuki Ichiki; Akihiko Maezawa; Hideo Hayashi
- Web page: https://patentgrep.com/patent/US5702572A

## CPC

- C02F 9/00: Multistage treatment of water, waste water or sewage
- B01D 53/002: {by condensation}
- B01D 53/007: {by irradiation}
- B01D 53/60: Simultaneously removing sulfur oxides and nitrogen oxides
- B01D 2251/2062: Ammonia
- B01D 2259/812: Electrons
- C02F 1/20: by degassing, i.e. liberation of dissolved gases (degasification of liquids in general B01D19/00; arrangement of degassing apparatus in boiler feed supply F22D)
- C02F 1/441: {by reverse osmosis}
- C02F 1/469: by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
- C02F 1/52: by flocculation or precipitation of suspended impurities {(C02F1/463 takes precedence)}
- C02F 3/286: {including two or more steps}
- C02F 2101/16: Nitrogen compounds, e.g. ammonia
- C02F 2103/18: from the purification of gaseous effluents
- C02F 2103/20: from animal husbandry
- C02F 2103/22: from the processing of animals, e.g. poultry, fish, or parts thereof
- C02F 2103/32: from the food or foodstuff industry, e.g. brewery waste waters
- Y02A 50/20: Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
- Y02E 50/30: Fuel from waste, e.g. synthetic alcohol or diesel
- Y02W 10/10: Biological treatment of water, waste water, or sewage
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT

## Abstract

The improved method of treating an exhaust gas from a combustion apparatus comprises adding ammonia to the exhaust gas and then irradiating it with an electron beam, characterized in that part or all of said ammonia is supplied as a separated portion of ammonia-containing water. The ammonia-containing foul water may contain feces excreted from humans and/or domestic animals and poultry, fermentation industry liquid waste or food processing wastewater. The organic waste-containing water may be digested anaerobically to convert the organic matter to methane gas and, subsequently, ammonia is separated from the supernatant liquor and used as the source of ammonia to be supplied. The methane gas is suitably used as a source of energy for the combustion apparatus. At least part of the organic matter in the organic foul water may be decomposed oxidatively and, subsequently, ammonia is separated for use as the source of ammonia to be supplied. The method is capable of simultaneous treatment of the exhaust gas and the ammonia-containing water in an efficient economical manner.

## Claims

### Claim 1

A method for treating ammonia-containing foul water and for treating exhaust gas from a combustion apparatus, comprising:
(a) removing coarse solid matter from an organic ammonia-containing influent water of night soil to obtain ammonia-containing effluent, subjecting the said effluent to an anaerobic digestion to degrade organic matter to obtain methane, carbon dioxide and water containing ammonia, and transferring said methane and carbon dioxide from said water containing ammonia into a vapor phase;
(b) recovering ammonia in vapor phase from said water containing ammonia by ammonia stripping, leaving ammonia-stripped water;
(c) condensing said ammonia in vapor phase to form an aqueous ammonia;
(d) treating said ammonia-stripped water with aerobic bacteria to provide biologically treated water;
(e) subjecting said biologically treated water to flocculation to form phosphorous flocculation-containing water;
(f) removing dust particles, using an electric precipitator, from an exhaust gas produced from combustion of a fossil fuel to provide a dust particle-free exhaust gas;
(g) subjecting said dust particle-free exhaust gas to heat exchange with boiler air in an air preheater to provide a heat-exchanged exhaust gas;
(h) cooling said heat-exchanged exhaust gas from step (g) with said phosphorous flocculation-containing water formed in step (e) to provide a cooled exhaust gas; and
(i) exposing said cooled exhaust gas to an electron beam from an electron generator in contact with ammonia obtained from said ammonia-stripping step (c), to obtain ammonium compounds.

### Claim 2 (depends on 1)

The method of claim 1 wherein part of the exhaust gas before it is freed of dust particles with the electric precipitator in the above step (f) is supplied to said ammonia-stripping.

### Claim 3 (depends on 1)

The method of claim 1 wherein noncondensable ammonia in the above step (c) is supplied directly into the step (i).

### Claim 4 (depends on 1)

The method of claim 1 wherein when the recovered water in the above step (e) contains high levels of NaCl, the water is subjected to a desalting treatment comprising reverse osmosis or electrodialysis to produce desalted water.

### Claim 5 (depends on 1)

The method of claim 1 wherein the methane obtained in the above step (a) is used as a source of energy for the combustion apparatus.