+

WO2008030235A2 - Procédé de récupération d'ammoniac - Google Patents

Procédé de récupération d'ammoniac Download PDF

Info

Publication number
WO2008030235A2
WO2008030235A2 PCT/US2006/034684 US2006034684W WO2008030235A2 WO 2008030235 A2 WO2008030235 A2 WO 2008030235A2 US 2006034684 W US2006034684 W US 2006034684W WO 2008030235 A2 WO2008030235 A2 WO 2008030235A2
Authority
WO
WIPO (PCT)
Prior art keywords
ammonia
stream
ion exchange
ammonium
combination
Prior art date
Application number
PCT/US2006/034684
Other languages
English (en)
Other versions
WO2008030235A3 (fr
Inventor
Alexander G. Fassbender
Original Assignee
Fassbender Alexander G
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fassbender Alexander G filed Critical Fassbender Alexander G
Priority to PCT/US2006/034684 priority Critical patent/WO2008030235A2/fr
Publication of WO2008030235A2 publication Critical patent/WO2008030235A2/fr
Publication of WO2008030235A3 publication Critical patent/WO2008030235A3/fr

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
    • C01C1/00—Ammonia; Compounds thereof
    • C01C1/02—Preparation, purification or separation of ammonia
    • C01C1/10—Separation of ammonia from ammonia liquors, e.g. gas liquors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D19/00—Degasification of liquids
    • B01D19/0005—Degasification of liquids with one or more auxiliary substances
    • B01D19/001—Degasification of liquids with one or more auxiliary substances by bubbling steam through the liquid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D19/00—Degasification of liquids
    • B01D19/0036—Flash degasification
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J39/00—Cation exchange; Use of material as cation exchangers; Treatment of material for improving the cation exchange properties
    • B01J39/04—Processes using organic exchangers
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05C—NITROGENOUS FERTILISERS
    • C05C3/00—Fertilisers containing other salts of ammonia or ammonia itself, e.g. gas liquor
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/20—Treatment of water, waste water, or sewage by degassing, i.e. liberation of dissolved gases
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/24—Treatment of water, waste water, or sewage by flotation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
    • C02F2001/422—Treatment of water, waste water, or sewage by ion-exchange using anionic exchangers
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
    • C02F2001/425—Treatment of water, waste water, or sewage by ion-exchange using cation exchangers
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/16—Nitrogen compounds, e.g. ammonia
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/06—Contaminated groundwater or leachate
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/32—Nature of the water, waste water, sewage or sludge to be treated from the food or foodstuff industry, e.g. brewery waste waters
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
    • C02F2103/36—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2303/00—Specific treatment goals
    • C02F2303/16—Regeneration of sorbents, filters

Definitions

  • Embodiments generally relate to a nutrient recovery process. More particularly, embodiments relate to a process for recovering ammonia and other nutrients from waste streams.
  • Waste streams contain several components which it is desirable to separate from the waste streams and from one another, either for recovery of the components for later use or to prevent release of the components or combinations of the components to the environment.
  • These waste streams may result from anaerobic digestion of sewage or animal wastes, from industrial processes such as rendering operations, from coke and chemical manufacture, and from food and agricultural processes.
  • a component which it is especially useful to separate from a nitrogen-containing waste stream (such as those types of waste streams mentioned above) is ammonia.
  • Anaerobic fermentation or digestion is a widely-practiced method of treating these nitrogen-containing wastes.
  • the anaerobic fermentation process involves converting degradable carbon compounds into methane and carbon dioxide, while simultaneously converting fixed, carbonaceous nitrogen into ammonia.
  • Anaerobically digested sewage sludge and animal wastes may be separated into a solids-rich stream and a solids-depleted stream, where the solids-depleted stream contains the bulk of the water as well as a variety of chemicals dissolved and suspended in the water.
  • a sludge or biosolids cake is formed (the solids-rich stream) along with a liquid stream often called a filtrate or centrate (the solids-depleted stream).
  • the suspended chemicals in the solids-depleted stream typically include ammonia nitrogen (NH 3 -N) having a typical concentration ranging from 400 parts per million (ppm) to 16,000 ppm, hardness in the form of calcium carbonate with a typical concentration ranging from 50 ppm to 350 ppm, phosphate having a typical range of concentration from 2 ppm to 150 ppm, and total suspended solids having a typical concentration range of 500 ppm to 2,000 ppm.
  • the filtrate or centrate (solids-depleted stream SD of Figure 1) typically contains the bulk of the ammonia nitrogen generated in the anaerobic digestion process.
  • Ammonia is present in the waste stream typically in the ammonium cation form. This ammonium cation (NH 4 + ) may be converted to ammonia (NH 3 ), which may be stripped from the centrate when the centrate pH is high. In the centrate, ammonium cations are usually paired with a roughly stoichiometric amount of bicarbonate anions at anaerobically- digested stream pH levels between 6 and 9. To raise the centrate pH to a high enough level to strip ammonia from the centrate, a base must be added to convert ammonium ion to ammonia. The desired reaction from the addition of the base (represented by OH " in the formula below) is as follows:
  • these waste streams also contain other dissolved ions such as calcium, magnesium, iron, and phosphate, also shown by the example centrate stream component concentrations in the table of Figure 2.
  • concentrations of calcium, magnesium, and phosphate ions in this example are relatively low due to the inherently soft water in New York City and the digested sludge having been treated with ferric chloride prior to centrifugation.
  • the ferric chloride lowers the pH, binds with phosphorous, and reduces the potential for struvite formation. If the pH of this centrate stream were raised above 9, struvite would form until the solubility equilibrium limit was attained, hi the case of the centrate composition shown in Figure 2, phosphate would be the limiting reactant in the formation of struvite.
  • ammonia recovery process which reduces operating costs of the ammonia recovery, such as by reducing heating costs of the ammonia recovery process, by reducing the damage to and/or clogging of equipment, and/or by decreasing the amount of base required to convert the ammonium ion in the waste stream to ammonia.
  • embodiments include a method for removing ammonia from a stream, the stream comprising therein soluble ammonia, ammonium ions, or a combination thereof and carbonate anions, bicarbonate anions, or a combination thereof, the method comprising reducing suspended solids from the stream by flotation, settling, or filtration; removing divalent and trivalent cations from the stream via ion exchange; converting any carbonate anions, bicarbonate anions, or the combination thereof in the stream to carbon dioxide by adding an effective amount of one or more acids; removing the carbon dioxide from the stream using one or more mass transfer devices; converting the ammonium ions to ammonia by adding an effective amount of one or more bases; and removing ammonia from the stream by converting the ammonia into a gaseous form and absorbing the gaseous ammonia into a separate solution.
  • Embodiments also include a method for removing ammonia from a stream, the stream comprising therein soluble ammonia, ammonium ions, or a combination thereof and carbonate, comprising reducing suspended solids from the stream by flotation, settling, or filtration; removing divalent and trivalent cations from the stream via ion exchange; absorbing any remaining ammonium ions in the stream onto an ion exchange resin; regenerating the ion exchange resin to form a high-ammonia spent solution; converting any ammonium cations in the high-ammonia spent solution to ammonia by addition of one or more bases; and recovering the ammonia from the spent solution by converting the ammonia into a gaseous form and absorbing the gaseous ammonia into a separate solution.
  • Further embodiments of the present invention include a method for removing ammonia from a waste stream, the waste stream comprising therein soluble ammonia, ammonium ions, or a combination thereof and carbonate anions, bicarbonate anions, or a combination thereof, the method comprising reducing suspended solids from the waste stream by flotation, settling, or filtration; removing divalent and trivalent cations from the waste stream via ion exchange using one or more ion exchange softening columns; diverting flow of the waste stream from a carbon dioxide stripping column and an ammonia stripping column disposed downstream from the one or more ion exchange softening columns; using the waste stream to convert one or more freshly regenerated ion exchange softening columns to ammonium form; and returning the one or more ion exchange softening columns to ion exchange service.
  • Yet further embodiments include a method for removing ammonia from a stream, the stream comprising therein soluble ammonia, ammonium ions, or a combination thereof and carbonate anions, bicarbonate anions, or a combination thereof, the method comprising reducing suspended solids from the stream by flotation, settling, or filtration; removing divalent and trivalent cations from the stream via ion exchange; removing the bicarbonate anions from the stream via ion exchange; if any carbon dioxide is present in the stream, removing the carbon dioxide from the stream using one or more mass transfer devices; converting the ammonium ions to ammonia by adding an effective amount of one or more bases; and removing ammonia from the stream by converting the ammonia into a gaseous form and absorbing the gaseous ammonia into a separate solution.
  • Figure 1 is a graph of titration data illustrating buffering effect of 3500 parts per million (ppm) bicarbonate in a centrate, where 3,500 ppm bicarbonate is titrated with 0.05M sodium hydroxide.
  • Figure 2 is a table showing analysis of a typical centrate composition, the composition data from Bowery Bay Water Pollution Control Plant in New York City.
  • Figure 3 is a flow chart of a first embodiment of an ammonia recovery process.
  • Figure 4 is a graph showing an ammonium load breakthrough curve.
  • Figure 5 is a flow chart of a second embodiment of an ammonia recovery process.
  • Embodiments of the present invention include a method and device for effectively, efficiently, and cost-effectively removing ammonia from a nitrogen-containing waste stream such as a wastewater or landfill leachate.
  • a nitrogen-containing waste stream such as a wastewater or landfill leachate.
  • Useful and valuable quantities of ammonia are recovered from a waste stream by use of methods and equipment of embodiments.
  • the waste stream may result from any process known to those skilled in the art which generates waste containing ammonia or the precursors to ammonia (nitrogen containing wastes), including but not limited to streams from anaerobic digestion of sewage or animal wastes, streams from industrial processes such as rendering operations and coke and chemical manufacturing processes, or related streams from food and agricultural processes.
  • Embodiments encompass an ammonia recovery process including low-cost bicarbonate buffer removal.
  • Ammonia recovery process embodiments of the present invention address the conflicting requirements and constraints associated with recovering ammonia from a waste stream in a highly reliable, cost-effective manner which includes reducing the amount of base needed to recover ammonia from the waste stream.
  • the processes and methods of operation of embodiments achieve a high degree of process equipment reliability by eliminating or reducing the potential for undesired solids precipitation (example undesired solids are calcium carbonate, calcium phosphate, magnesium ammonium phosphate hydrates (struvite), and magnesium hydroxide) in the equipment and/or associated valves, pipes, etc.
  • Embodiments eliminate the bicarbonate ion prior to addition of base, thereby reducing the quantity of base that is necessary to recover the ammonia from the waste stream. Some embodiments also eliminate the formation and collection of precipitates or solids by removing divalent and trivalent cations, the precipitate-forming materials, via ion exchange softening.
  • Wastewater is particularly susceptible to the formation of precipitates or solids such as calcium carbonate, calcium phosphate, and struvite due to the presence of calcium, ammonium, magnesium, and phosphate ions (the components which form struvite and the calcium precipitates) in the wastewater; therefore, the elimination of divalent and trivalent cations is particularly advantageous in the context of wastewater treatment.
  • no sludge is produced after ion exchange softening when recovering the ammonia with the use of one or more highly soluble bases such as sodium hydroxide instead of lime to convert ammonium to ammonia and to the use of one or more acids such as sulfuric acid to blow off the carbon dioxide prior to the ammonia removal.
  • carbonate or bicarbonate present in the waste stream is the corresponding anion for both the ammonium and divalent cations such as calcium and magnesium.
  • the divalent cations are removed up front in the ammonia recovery process so that solids (precipitates) are not formed (or at least negligible amounts of solids are formed) during the ammonia recovery process. Removing the bicarbonate up front reduces the amount of base necessary to recover the ammonia, thereby reducing the expense of the ammonia recovery process and increasing its efficiency. All or a portion of the bicarbonate and carbonate anions may be removed from the stream using anion exchange with a strong base anion resin in the chloride form.
  • the salt brine used to regenerate the strong base anion resin may, in most cases, be used simultaneously or in series the regenerate the strong acid cation resin used to remove the divalent and trivalent cations. Because the bicarbonate is typically present in a molar-equivalent amount significantly greater than the molar-equivalent amount of divalent and trivalent cations, there will typically be a mismatch between the amount of salt brine needed for anion resin regeneration and cation resin regeneration. In general with anaerobically digested wastes, the anion resin regeneration will require more brine than the cation resin. The brine necessary for the anion resin regeneration can be fully provided and thereby provide an excess of brine for the cation regeneration step.
  • a quantity of brine sufficient to regenerate the molar equivalents of hardness on the cation resin and a molar equivalent amount of amount of bicarbonate on a corresponding quantity of anion resin may be provided.
  • the anion resin would exhaust before the cation resin, and the bicarbonate anion would pass through the column.
  • This remaining bicarbonate slip may be treated with acid to convert the bicarbonate to carbon dioxide, and then the carbon dioxide would be removed as a gas.
  • one or more acids may be utilized to convert bicarbonate to carbon dioxide (CO 2 ), which is then removed from the waste stream as a gas, so that when the pH of the product stream is raised to form a more basic solution (such as by adding caustic), the amount of material utilized to raise the pH value of the product stream is decreased.
  • the expense of the ammonia recovery operation may be reduced due to the high expense of the material used to raise the pH (e.g., sodium hydroxide, caustic, and other soluble bases are relatively expensive).
  • Embodiments of the ammonia recovery process may include filtration, ion exchange, pH modification, gas stripping (contacting the liquid stream with inert gas to remove volatile components), and absorption (to remove contaminants from the gas stream).
  • Chemical inputs to the ammonia recovery process system may include polymer flocculent for addition to a dissolved-air flotation tank, as well as one or more bases such as sodium hydroxide (NaOH) or calcium hydroxide (Ca(OH) 2 ), one or more acids such as sulfuric acid (H 2 SO 4 ), and sodium chloride (NaCl) (or their chemical equivalents) for ammonia recovery.
  • bases such as sodium hydroxide (NaOH) or calcium hydroxide (Ca(OH) 2 )
  • acids such as sulfuric acid (H 2 SO 4 )
  • NaCl sodium chloride
  • useful and valuable quantities of ammonia are recovered from a waste stream using various processes and equipment.
  • Figure 3 shows a first embodiment of the ammonia recovery process of the present invention.
  • the first embodiment includes the method steps of filtering out suspended solids from the waste stream, softening the centrate to produce high ammonium content therein, removing the bicarbonate buffer, stripping ammonia (ammonia polishing) to convert the ammonium ion to ammonia and raise the pH of the centrate, and accomplishing absorption of the excess carbon dioxide.
  • the waste stream which may include for example sewage sludge or animal wastes (but may also include waste resulting from industrial processes such as rendering operations or food or agricultural processes, or from coke or chemical manufacture), is anaerobically digested by an anaerobic digester 1 to produce a digested sludge or waste stream W.
  • This digested waste stream W typically has a substantially neutral pH value (a pH of approximately 7).
  • the typical operational temperature of the anaerobic digester 1 is sufficient to provide the heat needed in the ammonia recovery process to recover the ammonia without additional heat exchange. Because the energy requirements of the system are greatly reduced by the elimination of the prior art requirement that other steps of the ammonia recovery process be heated, embodiments of the ammonia recovery process and system allow for low energy costs greatly reduced from the energy requirements of the prior art. Of course, it is also within the scope of alternate embodiments of the present invention to heat any of the stages, equipment, or streams of the ammonia recovery process if desired or necessary. In embodiments of the present invention, instead of added heat to the ammonia recovery system removing the ammonia, pressure is utilized to remove the ammonia from the waste stream.
  • the digested sludge W is then separated into a solids-rich stream SR and a solids- depleted stream SD (also referred to as "centrate” or “filtrate”).
  • the digested sludge W may be separated into these streams SD and SR by one or more separating devices 2, which may include one or more of any separating or filtering devices known to those skilled in the art, including but not limited to one or more centrifuges, filter presses, settling basins, and/or other filtering devices.
  • the solids-depleted stream SD contains the bulk of the water as well as a variety of chemicals dissolved and suspended in the water, the dissolved and suspended chemicals typically including ammonium bicarbonate (NH 4 HCO 3 ), calcium bicarbonate (Ca(HCO 3 ) 2 ) as the hardness, phosphate, and suspended solids.
  • NH 4 HCO 3 ammonium bicarbonate
  • Ca(HCO 3 ) 2 calcium bicarbonate
  • Some typical concentration ranges of these chemicals dissolved and suspended in the water are shown in Table 1 below:
  • the solids-depleted stream SD may contain other chemicals in addition to those listed above, and/or the constituents may be present in the solids-depleted stream SD in different concentrations.
  • the solids-depleted stream SD may be a centrate stream, while the solids rich stream SR may be a bio-solids cake.
  • Figure 2 shows a specific example of the concentrations of different components present in a centrate or solids-depleted stream in New York City.
  • the solids-rich stream SR After separating the solids-depleted stream SD from the solids-rich stream SR, the solids-rich stream SR containing bio-solids, the solids-rich stream SR may be collected in a vessel 101, further treated, or otherwise removed from the remainder of the ammonia recovery process .
  • the solids-depleted stream SD which contains raw centrate or filtrate from centrifuging or filtering equipment (or other separating equipment), may still contain suspended solids which must be removed prior to ammonia recovery processing.
  • a highly robust approach to removing these suspended solids couples dissolved air flotation with one or more multi-media and/or cartridge filters to achieve a low suspended solids stream.
  • one or more microfilters may optionally be utilized.
  • the solids-depleted stream SD may enter another separating/filtering device, specifically a dissolved air flotation unit ("DAF unit”) 125.
  • DAF unit dissolved air flotation unit
  • One or more flocculating agents or flocculents F are flowed into a dissolved air flotation unit (“DAF unit") 125, for example from tank 3.
  • the DAF unit provides means for removal of solids from the waste stream by injection of extremely fine air bubbles.
  • a high- solids return stream Rl of the solids-depleted stream SD may be combined with the waste stream W feeding into the separating device(s) 2 and then recycled back to the inlet of the one or more separating devices 2, so that the return stream Rl again passes through the separating device(s) 2 and DAF unit 125.
  • the filtered stream 4 exiting from the DAF unit 125 enters one or more filtering devices, such as one or more multimedia filters 13, and the filtered centrate stream 5 exiting from the one or more multimedia filters 13 may be further filtered using one or more cartridge filters 14.
  • the filtered centrate stream 6 may optionally be further filtered by one or more microfilters to effect further filtration of the suspended solids from the stream 6.
  • a high solids return stream R2 from the multi-media filter(s) 13 may be returned to the inlet of the separating device(s) 2 to allow for further filtration of the return stream R2 via another pass through the filtering devices 2, 125, 13, and 14.
  • the multi-media filter(s) 13, cartridge filter(s) 14, and/or microfilter(s) may be used to filter the solids-depleted stream SD in different orders than that shown in Figure 3, according to the specific application.
  • the filtered centrate stream 6 proceeds to the softening step described below.
  • the softening step involves softening the centrate to prevent formation of precipitates in the process equipment.
  • the centrate stream 6 is flowed through one of the two or more softening columns 15, the softening columns preferably being two or more cation exchange softeners and more preferably being two or more cation and ion exchange softeners.
  • the two or more softening columns 15 may be operated in a mode where at least one column is online while at least one column is offline and available for regeneration. This operational mode decreases the cost of the ammonia recovery process.
  • the softening column(s) 15 operate via ion exchange to remove precipitate- forming materials, such as calcium, magnesium, and iron ions, so that precipitates are not formed and do not cling to equipment walls to clog or damage other pieces of equipment in the ammonia recovery process and do not cling to walls of piping or other equipment to clog or damage piping or other equipment conveying the treated waste stream back to the plant.
  • precipitate- forming materials such as calcium, magnesium, and iron ions
  • the filtered centrate 6 is passed over a standard strong acid cation resin bed where calcium, magnesium, and iron ions are removed.
  • Potassium and ammonium have fairly similar affinities for the strong acid cation resin. Potassium will typically displace ammonium, but in the case of the influent centrate, the concentration of ammonium ions is roughly 18 times the concentration of the potassium ions.
  • a sharp separation between the potassium and ammonium ions may or may not be achieved. For the purposes of this analysis, consider the case where a reasonably sharp split between the potassium and ammonium ions is achieved. Assuming this sharp split imposes additional processing costs because it will be necessary to regenerate the softening column more frequently. Also, a purge or other treatment process must be added to the recirculated brine used to regenerate the polishing columns (described below).
  • Each equivalent of potassium and hardness in the influent filtered centrate 6 is exchanged for an equivalent of ammonium ion in the online softening column 15.
  • the ammonium concentration increases as the potassium and hardness is captured by the online softening column 15 by displacing ammonium ions, and the potassium and hardness is thereby eliminated (or at least reduced) from the centrate stream 6.
  • the online softening column 15 is saturated with potassium and hardness, the potassium in the feed will begin to break through, but the hardness will not.
  • the hardness will displace the potassium on the online softening column 15.
  • the softening column(s) 15 remove(s) precipitate- forming materials from the centrate of the waste stream, preventing precipitates from forming and clogging or damaging pipes or other equipment.
  • the online softening column 15 When the online softening column 15 is fully saturated with potassium and hardness (calcium, magnesium, and iron) and the ammonium ions on the online softening column 15 have been replaced with potassium and hardness, the online softening column 15 may be regenerated with sodium chloride (NaCl) brine solution 26 (and/or with sodium hydroxide, sodium chloride, brine, or a combination thereof).
  • the sodium chloride brine solution 26 may be dispensed from a brine regeneration solution tank 16, where the water and sodium chloride solution is located. The high concentration of sodium chloride in the brine stream 26 replaces the hardness on the online softening column 15 with sodium ions.
  • the spent brine stream 27 is purged from the online softening column 15 and may be discharged to a pH balance tank 28.
  • the brine regenerated column in the sodium form is converted to ammonium form by using the freshly-generated sodium form softener column as an ammonium ion polishing column until the sodium is displaced with the ammonium ion.
  • the pH-adjusted stream 30 is split off before the ammonia polishing operation (described below) and is used to convert the sodium form online softening column 16 to the ammonium form.
  • the treated low ammonia effluent stream 20 is pH adjusted, for example in the pH balance tank 28, and returned to the treated water plant as stream 32.
  • the bed would require approximately 28 hours to load with potassium and hardness before its need for regeneration would arise.
  • the partially-treated ammonium laden stream 30 from the entry to the ammonia polishing column(s) 31 (described below) is capable of displacing the sodium in approximately 16 hours of operation.
  • the softening column that is offline from softening duty may be operational for ammonium polishing duty.
  • the concentration of ammonia in the partially-treated stream 30 may be reduced and the time the offline softening column may be used for polishing is extendable. The benefits of this approach are explained below after this description of the entire ammonia recovery process.
  • the next step in the ammonia recovery process is the bicarbonate buffer removal.
  • bicarbonate buffer removal occurs as part of the ion exchange softening process where the bicarbonate ion is exchanged for chloride using a strong base anion resin and/or when the softened, high-ammonium centrate stream 7 which exits from the online softening column 15 flows into the carbon dioxide removal unit 33 to react with an acid.
  • Sulfuric acid also flows into the carbon dioxide removal unit 33 (for example from tank 34) via sulfuric acid stream 8.
  • the softened, high-ammonium centrate stream 7 is acidified with the sulfuric acid 8 to a pH of approximately 5.3, and the sulfuric acid reacts with the bicarbonate in the centrate stream 7 to form carbon dioxide and water.
  • the pH of the centrate stream 7 is preferably generally neutral, at approximately 6 to approximately 8, before entering the carbon dioxide removal unit 33.
  • the chemical reaction of the bicarbonate in forming the carbon dioxide upon addition of the acid is as follows (where HCO 3 " represents the bicarbonate anion in the centrate stream and H + represents the added acid): HCO 3 " + H + -» CO 2 + H 2 O
  • the carbon dioxide Upon formation of the carbon dioxide in the carbon dioxide removal unit 33, the carbon dioxide is removed into carbon dioxide stream 9 (which may also contain air) using the carbon dioxide removal unit 33, which may include an air blown packed or similar mass transfer column or a vacuum degassing unit. Although the vacuum degassing unit is typically more costly to build and run than the mass transfer column, the vacuum degassing unit generates a high-concentration carbon dioxide stream 9 (or carbon dioxide/air stream).
  • the carbon dioxide stream 9 (or carbon dioxide/air stream) is preferably not immediately discarded, but is instead re-used and a portion thereof returned to the partially-treated centrate in a subsequent step of the ammonia recovery operation to reduce pH of the partially-treated centrate (although it is within the scope of embodiments of the present invention to discard this carbon dioxide or carbon dioxide/air stream).
  • ammonia stripping or ammonia polishing which is the ultimate aim of the ammonia recovery process, requires the pH to be raised to approximately 10.5, it would appear to be counterproductive and would be counterintuitive to add acid prior to adding the required base.
  • using one or more acids for bicarbonate buffer removal was discovered by the present inventor to be highly economically favored due to the low cost of sulfuric acid (and/or other comparable acids) in comparison to the cost of sodium hydroxide (and/or other comparable bases), and due to the relatively small amounts of acid and base needed to shift the pH once the bicarbonate buffering capacity was eliminated in comparison to the large amount of base needed to raise the pH to 10.5 when the bicarbonate was present.
  • sulfuric acid is and generally will be less costly to use for this application than sodium hydroxide.
  • Sulfur and sulfuric acid are byproducts of energy production and have low and stable costs, hi contrast, sodium hydroxide and other comparable bases are made using electricity to split salt to form chlorine and sodium hydroxide; therefore, sodium hydroxide is expensive and becoming even more expensive.
  • Using low-cost sulfuric acid (or other comparable acid) in this counter-intuitive manner enables significant cost savings in ammonia recovery from bicarbonate buffered streams.
  • the un-buffered stream 10 proceeds to the next step of ammonia stripping (this term denotes removing ammonia from the stream and is also called ammonia polishing).
  • the stream 10 flows to ammonia stripper 35, which may be a vacuum stripping unit, vacuum stripper, vacuum distillation unit, and/or air stripper unit, where the pH of the stream 10 is raised to approximately 10.5 by one or more bases flowing into the ammonia stripper 35 via base stream 11, and the ammonia is removed as a gas via ammonia stream 36.
  • the base stream 11 is added to react with the ammonium ion and convert it to ammonia as well as to raise the pH to approximately 10.5.
  • the base which may be in the form of caustic
  • the chemical reaction upon addition of the one or more bases (represented by OH " ) is as follows (where NH 4 + is the ammonium cation):
  • the base stream 11 may be supplied by base tank 37, and the base may be sodium hydroxide.
  • the ammonia gas stream 36 may flow into a product tank 38 (which may hold therein a product of ammonium sulfate formed from ammonia gas in combination with sulfuric acid and other process streams).
  • a vacuum may be maintained within the ammonia stripper 35 using a venturi and circulation pump. The pump circulates a concentrated solution of ammonium sulfate and sulfuric acid (or other comparable acid and ammonium acid compound) at a rate that captures all of the ammonia and water vapor pulled into the venturi via ammonia stream 36.
  • An advantage of using a vacuum stripper rather than an air stripper is that dealing with air as an intermediate in the process is eliminated, so that the ammonia recovery process is accomplished in less time at less cost for several reasons.
  • mass transfer using an air stripper involves two time-consuming mass transfer steps, where in the first step ammonia must mix with air, and then in the second step the contents of the air stripper must change to the liquid phase while the ammonia is removed as a gas.
  • an air stripper requires heating for the mass transfer to occur, thereby increasing the energy costs for operating the system.
  • the pressure in the device is preferably maintained at a vacuum (with a preferable pressure of from approximately 1 absolute pressure per square inch (psia) to approximately 2.5 psia, most preferably approximately 1.9 psia, although this pressure range and preferable pressure are in no way limiting of the pressures at which the stripper mass transfer unit 35 may be maintained in embodiments or of the pressures at which a vacuum occurs in embodiments).
  • the liquid stream is provided a high surface area where the volatile ammonia passes into the gas phase.
  • a significant advantage of the vacuum approach is that a large mass fraction gas phase is ammonia as opposed to water (the ammonia vapor 36), and the gaseous ammonia is separated from the partially treated centrate stream 12 in the liquid phase.
  • the ammonia vapor in stream 36 instantly reacts with the acid liquid stream in tank 38 to form concentrated ammonium salt solutions such as ammonium sulfate.
  • vacuum stripping is faster than the air stripping (1 step versus 2 steps), does not require dealing with an air intermediate, and does not require any heating for the mass transfer to occur because the mass transfer in the vacuum stripping occurs due to pressure rather than temperature. For all of these reasons, vacuum stripping is less costly and simpler than air stripping.
  • the absorption step involves contacting the high-pH partially-treated centrate stream 12 exiting the ammonia stripper 35 and the carbon-dioxide-containing exhaust stream 9 from the degassing unit 33 in a carbon dioxide absorption tank 39.
  • the absorption tank may include a liquid-vapor mass transfer device, for example a packed column. Because a significant amount of ammonia was previously removed from the exhaust stream 9, a significant excess of carbon dioxide is available to react with the high-pH partially-treated centrate stream 12 to reduce its pH. Recovering a portion of the carbon dioxide byproduct and utilizing the resulting available carbon dioxide containing stream 9 saves sulfuric acid (or other acid being used in the ammonia recovery operation).
  • the partially-treated centrate stream 40 exits from the absorption tank with a lower pH, in one embodiment with a pH of from approximately 8 to a pH of approximately 10.
  • the carbon dioxide containing stream 9 is not added to the absorption tank 39, and the sulfuric acid (or other acid) added in subsequent steps (e.g., via stream 17) is used to lower the pH to the desired generally neutral value.
  • the partially-treated centrate stream 40 may optionally be filtered by one or more optional filtering devices, for example by one or more cartridge filters 41.
  • the filtered centrate stream 42 exits from the one or more filtering devices.
  • sulfuric acid may be added via acid stream 17 (for example from the sulfuric acid tank 34, although a different tank may also be utilized) to the filtered centrate stream 42 (or to the stream 40 if no filtering devices 41 are present), as needed, to further reduce the pH of the stream 40 or 42 to result in a pH ranging from approximately 6 to approximately 7 in stream 43, thereby ensuring that all of the ammonia remaining in the stream 40 or 42 is converted to the ammonium form.
  • the desired result is stream 43 having a generally neutral pH.
  • Stream 43 may be split into two streams 30 and 18, each having a pH of approximately 7 and a concentration of ammonium nitrogen of approximately 225 ppm. Streams 30 and 18 are sent to different places for different amounts of time. Stream 30 flows into the softening operation to convert the sodium column to an ammonium column (softener regeneration), while stream 18 flows into the polishing operation (described below).
  • Stream 30 is sent to the online brine regenerated softening column 15 to convert it to the ammonium form. Converting the softening column 15 to the ammonium form improves the overall process and utilizes ammonia adsorption capacity which would otherwise be wasted. If the softening columns 15 were placed back into operation without this conversion to the ammonium form, all of the ammonium ions would displace the sodium ions on the softening columns 15, and for a time no ammonium would exit the softening columns 15.
  • the graph of Figure 4 which illustrates this undesirable result when the softening columns 15 are not converted to ammonium form, shows the absorption breakthrough curves for the ammonium ion from the example centrate stream of the table of Figure 2 after multiple regeneration steps using brine as the regenerant. Note that low levels of ammonium ions are achievable.
  • the data in Figure 4 was generated using centrate having approximately 1,000 ppm ammonium nitrogen, and improved performance is expected in industrial-sized columns being fed approximately 225 ppm ammonium concentration.
  • the softening columns 15 would simply absorb all of the ammonium ions in stream 6 until the sodium was no longer present, and the softening columns 15 would then operate as an ammonium softening column for the remainder of its softening capacity.
  • stream 6 were sent to a freshly regenerated online softening column 15 in the sodium form, approximately 3.7 hours would pass before any ammonium ions exited the softening column 15. During this time, the ammonium ions in stream 6 would displace the sodium on the softening column 15, while the downstream processing equipment would not be processing anything.
  • this 3.7-hour gap is a step function that would repeatedly introduce significant process control challenges every 28 hours, disadvantageously requiring downstream equipment to idle or shut down and be restarted. Therefore, by utilizing the sodium-form softening column 15 as a polisher for stream 30, the step function is avoided in normal operation of the equipment, and the equipment and chemical use efficiencies are realized.
  • the embodiment of Figure 3 provides an ammonia recovery process possessing an intrinsic alternate capacity which allows the carbon dioxide and ammonia removal equipment to be bypassed for a set window of time without the loss of plant performance, enabling maintenance, repair, and/or replacement of the carbon dioxide and/or ammonia removal equipment without complete shutdown of the overall operation for a period of time.
  • the sodium form softening columns 15 could be used to provide approximately 3.7 hours of ammonia capture, allowing the flow to the carbon dioxide removal equipment and ammonia removal equipment to be bypassed.
  • the direction of fluid flow in the line containing stream 30 is reversed, and the centrate stream flows from the softening column 15 directly to the polishing columns 31 instead of to the degassing unit 33 as stream 7.
  • Presuming the polishing columns 31 are the same size as the softening columns 15 (which is not required for embodiments of the present invention), then adding the capacity of the polishing columns 31 to the capacity of the softening columns 15 would add an approximately 3.7 to approximately 7.4 hours of additional treatment capacity to the ammonia recovery system.
  • up to approximately 11.1 hours of capacity would be provided by this mode of operation using polishing columns 31 in addition to the softening columns 15 where the carbon dioxide and ammonia removal equipment could be bypassed.
  • This increased built-in capacity is particularly useful for processing sites having limited space, where the normal design practice of ensuring reliability by using redundant equipment may be difficult or precluded due to this lack of available space. Furthermore, the additional built-in capacity is useful when the ability to schedule down-time is precluded because the centrate feed needs processing 24 hours/day, 7 days/week, and 365 days/year, so that minimal or no routine down-time is desired, even for routine maintenance. These constraints are real for many large, urban wastewater treatment plants.
  • Stream 18 flows through ammonia polishing columns 31 (preferably, although not necessarily, at least two columns), where the ammonium ions are exchanged with the sodium ions on the ammonia polishing columns 31.
  • the ammonium polishing columns 31 may be designed to meet design criteria including minimum process unit capital cost, some equipment size restraints, maximum spent brine ammonium concentration, and/or adequate back-up processing capacity in the event of a bypass situation as described above.
  • An optional second ammonia stripper 51 which may be a vacuum stripping unit, vacuum stripper, distillation unit, air stripper unit, another type of vacuum unit, or any other gas stripping or gas removal unit known to those skilled in the art, may be disposed downstream of the ammonia polishing columns 31 to remove any remaining ammonia gas 24 from stream 22 exiting from the polishing columns 31.
  • Stream 22 which contains mostly brine, flows into the vacuum unit 51, and any ammonia gas 24 is stripped from this stream 22 and sent to product recovery, for example to the product tank 38 (the product may be ammonium sulfate).
  • the ammonia polishing columns 31 may be regenerated by a brine solution (and/or with sodium hydroxide, sodium chloride, brine, or a combination thereof), delivered for example via brine regeneration solution stream 21 from a brine regeneration solution tank 50 (containing water and sodium chloride therein).
  • the ammonium polishing column regeneration brine solution 21 may be continuously reused, as sodium from the base tank 37, base stream 23 (which may be a base such as caustic or sodium hydroxide), continuously replaces the sodium lost in the ammonia polishing columns 31 during the ion exchange with the ammonium ion.
  • sulfuric or hydrochloric acid may optionally be utilized to regenerate the columns 15 and/or 31.
  • Brine flowing through the ammonia stripper 51 via stream 22 may be split into two brine streams, namely a first brine stream 52 recycled back into the brine regeneration solution recycle tank 50 and a second brine stream 25 (recycled brine purge) recycled into the brine regeneration solution tank 16 associated with the softening columns 15.
  • Flow from the brine regeneration solution recycle tank 50 via the brine regeneration solution stream 21 is used to generally continuously regenerate the ammonia polishing columns 31, while flow from the brine regeneration solution tank via stream 26 regenerates the ammonia softening columns 15.
  • This recycled brine is combinable with optional additional brine feed streams 53, 54 flowing into their respective tanks 16, 50 (the additional brine feed may be formed from a water and sodium chloride solution).
  • make-up water and salt via the additional brine feed streams 53 or 54 may be needed to replace column clingage losses.
  • the make-up water may be provided as a partial wash.
  • the only ammonium loss is the clingage at the end of a regeneration cycle.
  • a process operation such as continuous purge or periodic replacement of the recirculated brine may be necessary to control potassium buildup.
  • the brine streams 25 and 52 preferably possess a pH of approximately 10.5 when they exit the ammonia stripper 51. Adjustment of the pH of these streams to neutral may be accomplished if desired, but this pH adjustment is not necessary because the quantity of the hydroxide anion available for reaction with ammonium on a polishing column saturated with ammonium ions is negligible compared to the caustic required to convert those ammonium ions to ammonia.
  • the ion exchange columns used in both the softening and polishing operations as softening columns 15 and polishing columns 31 may be duplex or triplex so that each column, in the course of normal operation, is capable of being shut down so that maintenance or repair may be performed (or the offline column may be replaced) while the other column(s) of the duplex or triplex is/are in service performing the softening or polishing task.
  • duplex softening columns 15 shown and described above, after regeneration and conversion of the sodium form to the ammonium form, one of the columns could be idle for approximately 12 hours before the other operating, online column becomes exhausted in softening ability.
  • the carbon dioxide removal unit 33 and the ammonia removal unit 35 are designed for continuous operation and must be shut down for repair, replacement, or significant maintenance.
  • the treated centrate stream 19 exiting from the ammonia polishing columns 31 is sent to pH balance and discharged from the ammonia recovery process or stored, specifically for example sent to the pH balance tank 28 where the pH of the centrate stream 19 is lowered to a value ranging from approximately 6 to approximately 7 and discharged via stream 32.
  • the discharged stream 32 may be returned to the plant (e.g., water plant), re-used, stored, or further treated.
  • the gas stream 55 flows outward from the system, for example to a system gas odor scrubber 56 for odor control of the gas.
  • a gas stream 57 flowing from the pH-balance tank 28.
  • the treated centrate streams 55 and 20 after being balanced with the brine stream 27 within the pH balance tank 28 and after the gas 57 is purged from the tank 28, result in treated water stream 32 which may be returned to the plant for re-use, recycled through the ammonia recovery system, stored, or otherwise exit the ammonia recovery system.
  • a second embodiment of the ammonia recovery process is depicted in Figure 5.
  • This embodiment is especially useful when the ammonium ion concentration in the solids- depleted stream SD (the centrate or filtrate stream) is low, preferably where the ammonium ion concentration in the solids-depleted stream SD is less than approximately 500 ppm and more preferably where the ammonium ion concentration is less than approximately 400 ppm.
  • the carbon dioxide removal equipment and the ammonia removal equipment for processing the main centrate stream are eliminated (or at least not operated).
  • the ammonia recovery process is operated with a softening step having an integrated polishing step.
  • the ammonia recovery process depicted in Figure 5 is much simpler than the ammonia recovery process of Figure 3, but the process of Figure 5 retains the two separate brine systems.
  • the components 1, 2, 101, 125, 3, 13, and 14 and streams W, R2, Rl, SD, SR, F, 4, 5, and 6 operate in the same manner and are configured the same as the components of the same number described above in relation to the first embodiment of Figure 3.
  • the ammonia softening columns 115, ammonia polishing columns 131, ammonia stripper/vacuum unit 135, brine regeneration tank 116, brine regeneration solution recycle tank 150, product tank 138, acid tank 134, caustic tank 137, and pH balance tank 128 (also termed a "return equalization tank") of the second embodiment shown in Figure 5 are essentially the same in configuration and operation as the softening columns 15, ammonia polishing columns 31, ammonia stripper/vacuum unit 35, brine regeneration tank 16, brine regeneration solution recycle tank 50, product tank 38, acid tank 34, caustic tank 37, and pH balance tank 28, respectively, described above in relation to Figure 3, but the ingoing and outgoing streams to and from the above-listed components may be different for each embodiment.
  • a first brine system regenerates the online softening column 115 once it has been exhausted, and this spent brine is discarded from the ammonia polishing system as brine stream 160, for example discarded to the pH balance tank 128 for combination with the polished, treated centrate stream 119 flowed from the ammonia polishing columns 131 to the return equalization tank 128.
  • the first brine system may include a first brine regeneration solution tank 116 from which a brine stream 126 may flow into the online softening column 115. Make-up water and sodium chloride solution 53 may flow into the brine regeneration solution tank 116 to supplement a recycled brine purge 152 flowing from the ammonia stripper 135.
  • the second brine system regenerates the polishing column(s) 131 once they are loaded with ammonium ions.
  • the second brine system may include a second brine regeneration solution recycle tank 150 from which a brine stream 121 may flow into the ammonia polishing column(s) 131.
  • Make-up water and sodium chloride solution 54 may flow into the brine regeneration solution recycle tank 150 to supplement a recycled brine stream 225 flowing from the ammonia stripper 135.
  • the second brine stream 122 is processed using the ammonia stripper 135 (which may include any stripping device known to those skilled in the art, for example an air or vacuum stripper, although preferably a vacuum stripper), and the treated brine 225 is re-used in the ammonia polishing column(s) 131 (recycling of the brine is evidenced by streams 121, 122, and 225 flowing through the polishing columns 131, ammonia stripper 135, and brine regeneration solution recycle tank 150).
  • the ammonia stripper 135 which may include any stripping device known to those skilled in the art, for example an air or vacuum stripper, although preferably a vacuum stripper
  • the treated brine 225 is re-used in the ammonia polishing column(s) 131 (recycling of the brine is evidenced by streams 121, 122, and 225 flowing through the polishing columns 131, ammonia stripper 135, and brine regeneration solution recycle tank 150).
  • the sodium ions from the caustic soda 111 (which may be delivered via the caustic tank 137 to the ammonia stripper 135, and which may optionally include another base instead of caustic soda) replace those lost during the ion exchange process of the polishing column(s) 131.
  • the benefit of the brine regeneration approach of the second embodiment is that at ammonium ion concentrations of less than 500 ppm, sufficient time exists between the column exhaustions to achieve regeneration of the spent columns.
  • the equivalents of hardness may be fairly close to the equivalents of ammonia capacity.
  • this system it is possible to arrange the columns 115 and 131 in a carousel arrangement, where the hardness removal duty is passed from column to column around the carousel.
  • an arrangement of four columns may be used, with one column performing softening duty, one column prepared in the ammonium form to take on softening duty in the future, and the other two columns performing ammonium ion recovery duty.
  • the hardness removed and ammonia recovery regeneration cycles can be performed in tandem.
  • the cycle time for the ammonium ion regenerations are once every 9 hours (an approximate value). This cycle time provides adequate time for regeneration of spent columns 115, 131 for either ammonium ion or hardness removal.
  • An advantage of the low ammonium ion concentration process of the second embodiment depicted in Figure 5 is that it avoids the need to eliminate the bicarbonate anion.
  • ammonium bicarbonate in the feed stream is converted into sodium bicarbonate in the ion exchange columns 115, 131.
  • ammonia recovery process of the first embodiment shown in Figure 3 or of the second embodiment shown in Figure 5 is primarily driven by the overall economics and local requirements.
  • the product ammonium sulfate may be utilized as a commercial grade fertilizer.
  • the nitrogen in the form of ammonia found in the waste stream is thereby efficiently and cost-effectively converted to a usable product by use of the above-described methods and apparatus.
  • the recovery of ammonia in the form of ammonium sulfate or in any other form using the above-described methods and apparatus advantageously limits nitrogen discharge into bodies of water, as often required by environmental regulations, along with providing a usable end-product (e.g., ammonium sulfate).
  • the ammonium sulfate (or other formed product) is capable of being crystallized to form a pure product.
  • flow switching based on conductivity may be utilized in the above-described ammonia recovery process.
  • the brine discussed above may include any relative concentrations of sodium chloride and water in embodiments of the present invention, the brine may optionally include, for example, approximately 10% sodium chloride.
  • a further alternate embodiment involves using an anion resin to remove the bicarbonate during the cation softening step.
  • an anion resin to remove the bicarbonate during the cation softening step.
  • the brine may be used to remove both the bicarbonate and the hardness, and the acid addition step to remove the carbon dioxide may optionally be bypassed.
  • Enough brine may be provided to remove the bicarbonate and to re-use this brine to also remove the hardness.
  • Another embodiment entails taking out the extra bicarbonate and placing it through acid treatment.
  • Ion exchange and the ion exchange process is shown and described in "Ion Exchange Primer," pages 1-12, distributed by Sybron Chemicals, Inc., which is herein incorporated by reference in its entirety. Any of the ion exchange principles, resins, equipment, and operations described in the "Ion Exchange Primer" may be utilized in any of the above embodiments.
  • the brine may be substituted with sodium hydroxide, sodium chloride, brine, or a combination or solution thereof.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Analytical Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Physical Water Treatments (AREA)
  • Treating Waste Gases (AREA)

Abstract

Certains modes de réalisation concernent un procédé et un appareil pour récupérer de manière efficace et économique de l'ammoniac d'un courant de déchets. Selon certains modes de réalisation, l'ammoniac est récupéré après l'élimination d'un tampon bicarbonate du courant de déchets par addition d'un acide.
PCT/US2006/034684 2006-09-06 2006-09-06 Procédé de récupération d'ammoniac WO2008030235A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/US2006/034684 WO2008030235A2 (fr) 2006-09-06 2006-09-06 Procédé de récupération d'ammoniac

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2006/034684 WO2008030235A2 (fr) 2006-09-06 2006-09-06 Procédé de récupération d'ammoniac

Publications (2)

Publication Number Publication Date
WO2008030235A2 true WO2008030235A2 (fr) 2008-03-13
WO2008030235A3 WO2008030235A3 (fr) 2008-08-07

Family

ID=39157713

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2006/034684 WO2008030235A2 (fr) 2006-09-06 2006-09-06 Procédé de récupération d'ammoniac

Country Status (1)

Country Link
WO (1) WO2008030235A2 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101780421A (zh) * 2010-03-12 2010-07-21 中南大学 一种氨氮吸附剂及其制备和使用方法
EP2543641A1 (fr) * 2011-07-06 2013-01-09 Biotain AB Procédé et dispositif pour se charger d'un nitrogène présent dans un liquide
CN103382073A (zh) * 2013-07-15 2013-11-06 浙江斯科能科技股份有限公司 一种垃圾渗滤液资源化处理的膜分离与生化工艺及其装置
CN104341069A (zh) * 2013-07-25 2015-02-11 中国石油化工股份有限公司 一种净化乙苯催化脱氢制苯乙烯过程中所产生的工艺凝液的方法
EP3782959A4 (fr) * 2018-07-26 2021-06-16 Mitsubishi Heavy Industries Engineering, Ltd. Appareil et procédé de traitement d'eaux usées de purification de gaz d'énergie
CN115679128A (zh) * 2022-11-08 2023-02-03 厦门钨业股份有限公司 一种高效从含钨除磷沉淀渣中回收钨和氨的方法
US20230211280A1 (en) * 2021-12-31 2023-07-06 Stephen R. Temple Methods for Absorbing a Targeted Compound from a Gas Stream for Subsequent Processing or Use

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3984313A (en) * 1973-09-18 1976-10-05 Chemical Separations Corporation Preferential removal of ammonia and phosphates
US4689156A (en) * 1985-11-12 1987-08-25 Amax Inc. Removal of ammonia from wastewater
US6464875B1 (en) * 1999-04-23 2002-10-15 Gold Kist, Inc. Food, animal, vegetable and food preparation byproduct treatment apparatus and process

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3984313A (en) * 1973-09-18 1976-10-05 Chemical Separations Corporation Preferential removal of ammonia and phosphates
US4689156A (en) * 1985-11-12 1987-08-25 Amax Inc. Removal of ammonia from wastewater
US6464875B1 (en) * 1999-04-23 2002-10-15 Gold Kist, Inc. Food, animal, vegetable and food preparation byproduct treatment apparatus and process

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101780421A (zh) * 2010-03-12 2010-07-21 中南大学 一种氨氮吸附剂及其制备和使用方法
EP2543641A1 (fr) * 2011-07-06 2013-01-09 Biotain AB Procédé et dispositif pour se charger d'un nitrogène présent dans un liquide
CN103382073A (zh) * 2013-07-15 2013-11-06 浙江斯科能科技股份有限公司 一种垃圾渗滤液资源化处理的膜分离与生化工艺及其装置
CN104341069A (zh) * 2013-07-25 2015-02-11 中国石油化工股份有限公司 一种净化乙苯催化脱氢制苯乙烯过程中所产生的工艺凝液的方法
CN104341069B (zh) * 2013-07-25 2016-01-20 中国石油化工股份有限公司 一种净化乙苯催化脱氢制苯乙烯过程中所产生的工艺凝液的方法
EP3782959A4 (fr) * 2018-07-26 2021-06-16 Mitsubishi Heavy Industries Engineering, Ltd. Appareil et procédé de traitement d'eaux usées de purification de gaz d'énergie
US20230211280A1 (en) * 2021-12-31 2023-07-06 Stephen R. Temple Methods for Absorbing a Targeted Compound from a Gas Stream for Subsequent Processing or Use
CN115679128A (zh) * 2022-11-08 2023-02-03 厦门钨业股份有限公司 一种高效从含钨除磷沉淀渣中回收钨和氨的方法
CN115679128B (zh) * 2022-11-08 2024-04-16 厦门钨业股份有限公司 一种高效从含钨除磷沉淀渣中回收钨和氨的方法

Also Published As

Publication number Publication date
WO2008030235A3 (fr) 2008-08-07

Similar Documents

Publication Publication Date Title
US20080053909A1 (en) Ammonia recovery process
CA2700467C (fr) Elimination selective de sulfate par echange d'anions exclusif dans des flux de dechet d'eau dure
KR101329523B1 (ko) 스트림으로부터의 암모늄/암모니아 제거
AU2008366066B2 (en) Methods and systems for processing waste water
CN109867381A (zh) 从废水生产纯盐
US20100089740A1 (en) Method and systems for processing waste water using zero process water discharge
WO2008030235A2 (fr) Procédé de récupération d'ammoniac
CN103214115B (zh) 一种强酸阳离子交换树脂贫再生的水处理方法
EP3265215B1 (fr) Systèmes et procédés pour le traitement d'eau résiduaire diluée
CN109502842B (zh) 一种煤气化炉废水处理与资源化利用工艺
CN111170520A (zh) 脱硫废水的处理工艺和处理系统
US20080053913A1 (en) Nutrient recovery process
CN105923820A (zh) 一种烟气脱硫废水近零排放处理工艺
CN110937728A (zh) 一种脱硫废水的处理方法及处理系统
CN112093965A (zh) 一种用于矿井水处理的适度分步协同预处理工艺
CN205442916U (zh) 一种含盐废水处理系统
KR101825784B1 (ko) 정삼투법을 이용한 액비 제조 시스템 및 제조 방법
CA2257450A1 (fr) Procede de desalination partiel de l'eau
WO2008030234A1 (fr) Procédé de récupération de nutriments
CN106145498A (zh) 一种火电厂高含盐废水零排放回收处理方法
CN107522350B (zh) 废水处理系统和废水处理方法
US7371326B2 (en) Water treatment/remediation system
CN104671572A (zh) 一种火电厂脱硫废水电渗析软化浓缩处理系统及方法
CN117049755B (zh) 一种煤制气废水的中水回用处理工艺
CN117401841A (zh) 高盐有机废水资源化处理装置及方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 06824899

Country of ref document: EP

Kind code of ref document: A2

DPE2 Request for preliminary examination filed before expiration of 19th month from priority date (pct application filed from 20040101)
NENP Non-entry into the national phase in:

Ref country code: DE

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC, EPO FORM 1205A DATED 05-08-2009.

122 Ep: pct application non-entry in european phase

Ref document number: 06824899

Country of ref document: EP

Kind code of ref document: A2

点击 这是indexloc提供的php浏览器服务，不要输入任何密码和下载