# US 11,897,823 B2 · Production of nitrogenous fertilizer from wastewater

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- Number: US 11,897,823 B2
- Document ID: US11897823B2
- Status: Granted
- Kind: B2
- Application number: 17/962,455
- Filed: 2022-10-07
- Published: 2023-05-11
- Granted: 2024-02-13
- Earliest claimed: 2021-11-11
- Assignees: Pwg LLC
- Applicants: Pwg LLC
- Inventors: Edward Rosenthal; Griffith Lunn
- Web page: https://patentgrep.com/patent/US11897823B2

## CPC

- C05C 3/005: {Post-treatment}
- C02F 1/02: by heating (methods of steam generation F22B; preheating boiler feed-water or accumulating preheated boiler feed-water F22D)
- 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 1/66: by neutralisation; pH adjustment (for degassing C02F1/20; using ion-exchange C02F1/42; for flocculation or precipitation of suspended impurities C02F1/52; for removing dissolved compounds C02F1/58)
- C05B 7/00: Fertilisers based essentially on alkali or ammonium orthophosphates (C05B11/00 takes precedence)
- C05C 3/00: Fertilisers containing other salts of ammonia or ammonia itself, e.g. gas liquor
- C05F 7/00: Fertilisers from waste water, sewage sludge, sea slime, ooze or similar masses
- C05G 5/35: Capsules, e.g. core-shell
- C05G 5/38: {layered or coated with wax or resins}
- C02F 2101/16: Nitrogen compounds, e.g. ammonia
- C05C: NITROGENOUS FERTILISERS
- 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)
- C05B: PHOSPHATIC FERTILISERS
- C05F: ORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C, e.g. FERTILISERS FROM WASTE OR REFUSE
- C05G: MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS (organic fertilisers containing added bacterial cultures, mycelia, or the like C05F11/08; organic fertilisers containing plant vitamins or hormones C05F11/10); FERTILISERS CHARACTERISED BY THEIR FORM

## Abstract

An ammonia capture and recovery system comprises five process steps, including an ammonia removal step, an ammonia recovery step, a product granulation step, a granulated product wax-coating step, and a granulated product encapsulation step. These steps are modular in that multiple approaches are valid for each step if it meets the process requirements for the next influent. Also, a method of taking ammonia-containing wastewater and producing several water fractions (preferably of decreasing volume and increasing purity) and a time-release ammonium-containing fertilizer, resulting in a sustainable nitrogenous fertilizer product that reduces fertilizer use and subsequent nutrient runoff while being produced from wastewater and not fossil fuel or hydrogen sources.

## Claims

### Claim 1

A method of obtaining a granulated nitrogen-containing encapsulated fertilizer product from wastewater, wherein the method comprises an ammonia capture and recovery system comprising five method steps, wherein the method steps include an ammonia removal step to produce a stream comprising a gas with entrained ammonia and water, an ammonia recovery step producing an ammonium salt by addition of a mineral acid to the gas with entrained ammonia and water, a granulation step of the ammonium salt forming a granulated product, a granulated product wax-coating step, and a granulated product encapsulation step.

### Claim 2 (depends on 1)

The method of claim 1, wherein the method steps are carried out in a modular system and various temperatures and/or pressures can be employed in each step if it meets the process requirements for the next step's influent.

### Claim 3 (depends on 1)

The method according to claim 1, comprises providing an alkaline pH, gas, and heat component to provide method operating conditions for the ammonium removal step using an influent of ammonia-containing wastewater.

### Claim 4 (depends on 3)

The method of claim 3 comprises producing a product water with trace ammonia as well as a separate stream of gas with entrained ammonia and water at a higher concentration than the influent water stream.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the granulation step comprises heating a feed stream of a saturated solution of liquid ammonium salt in water to produce an effluent stream of product water and a product stream of granulated ammonium salt.