Aqueous phase removal of nitrogen from nitrogen compounds

A method is disclosed for denitrification of compounds containing nitrogen present in aqueous waste streams. The method comprises the steps of (1) identifying the types of nitrogen compounds present in a waste stream, (2) determining the concentrations of nitrogen compounds, (3) balancing oxidized and reduced form of nitrogen by adding a reactant, and (4) heating the mixture to a predetermined reaction temperature from about 300.degree. C. to about 600.degree. C., thereby resulting in less harmful nitrogen and oxygen gas, hydroxides, alcohols, and hydrocarbons.

FIELD OF THE INVENTION 
The present invention relates to a method of denitrification of compounds 
containing nitrogen including nitrates, ammonia, nitro-organic compounds, 
amides and amines. Such compounds are found in aqueous waste streams of 
sewage treatment and metal finishing plants and treatment by this method 
results in less harmful nitrogen gas, oxygen gas, hydroxides, alcohols, 
and hydrocarbons. 
As used herein, the term aqueous is used to mean of, relating to or 
resembling water, in a liquid or a supercritical phase. 
BACKGROUND OF THE INVENTION 
Compounds containing nitrogen including but not limited to nitrates, 
nitrites, nitro-organic compounds, ammonia, amines, and amides are often 
present together in various combinations in non-radioactive aqueous mixed 
waste streams such as sewage, sewage sludge, nitrate or nitrite wastes at 
metal finishing plants, and chemical and munitions plants. Nuclear 
materials production facilities also generate waste streams containing 
both nitrogen bearing compounds and radioactive materials. 
In many waste or process streams, the concentration of nitrogen compounds 
is below 1% which is insufficient for cost effective removal of nitrogen 
compounds by traditional means. Removal of nitrogen from nitrogen bearing 
streams of higher concentration may be precluded by the presence of 
hazardous chemicals and/or radioactivity. Moreover, nitrogen compounds at 
any concentration in a waste stream, present problems such as nitrous 
oxide (NO.sub.x) emission upon disposal by incineration, and algae bloom 
induced eutrophication upon disposal by drainage into bodies of water. 
Of the many methods of denitrification, very few are effective for anything 
other than a single nitrogen containing compound For example, The Nalco 
Water Handbook, 1979, pp. 6-11, states that "[t]he only chemical process 
that removes nitrate is anion exchange". However, the anion exchange 
process suffers from a number of disadvantages including 1) other nitrogen 
compounds are unaffected by the anion exchange, 2) additional chemicals 
are required to regenerate the anion exchange resin and 3) additional 
chemicals are required to regenerate the anion exchange resin and a waste 
stream is produced upon resin regeneration. 
Further examples of single nitrogen compound removal include methods of 
ammonia removal The Handbook (pp. 6-10) also states that "[a]mmonia can be 
removed by degasification, by cation exchange on the hydrogen cycle, and 
by adsorption on certain clays, such as clinoptilolite". The disadvantage 
of these processes is that since they are primarily directed toward 
removal of ammonia, other compounds containing nitrogen are generally 
unaffected. A further disadvantage of these processes is that the pH of 
the waste stream must be raised to increase the vapor pressure of aqueous 
ammonia. 
Another method of ammonia removal is by addition of chlorine to form 
nitrogen gas and hydrochloric acid. For purposes of toxic waste 
remediation, it is undesirable to handle chlorine or produce hydrochloric 
acid, and not all nitrogen compounds will release nitrogen gas upon 
addition of chlorine. 
Hydrazine (N.sub.2 H.sub.4), may be removed by reaction with dissolved 
oxygen to produce nitrogen gas and water. However, any other nitrogen 
compounds that may be present remain unaffected by this reaction. 
Each of the denitrification processes described so far are effective for 
removing one type of nitrogen compound. Removal of multiple nitrogen 
compounds by these methods requires use of multiple methods. 
There are currently two methods capable of removing multiple nitrogen 
compounds, bacterial processing and incineration. Conventional bacterial 
systems usually require a settling pond or biological reactor, are carried 
out at temperatures below 30.degree. C., require equipment to handle great 
quantities of air and require residence times on the order of days to 
reduce nitrogen compound concentrations below acceptable limits. 
In cases where nitrogen bearing waste streams are incinerated, undesirable 
nitrous oxide (NO.sub.x) emissions, components of smog, are produced. 
NO.sub.x can be combined with ammonia and destroyed by gas phase reactions 
at temperatures between 1000.degree. C. and 1100.degree. C. (known as 
thermal deNOx) or by selective catalytic reduction, at temperatures 
between 650.degree. C. and 750.degree. C. in the presence of a catalyst to 
convert the NO.sub.x to nitrogen, oxygen, and water. Disadvantages of 
treating nitrous oxides in the gas phase include, but are not limited to, 
1) the size of the equipment required for handling gases, 2) the high 
temperature operation, 3) handling potentially corrosive condensate after 
the gas stream is cooled and 4) the cost of disposal of a spent catalyst 
after processing radioactive wastes. 
Nitrogen compounds may be converted to a second nitrogen compound, but this 
does not fully remove nitrogen compounds. For example, cases where waste 
streams have a high chemical oxygen demand (COD) from the presence of 
carbonaceous and nitrogenous compounds, wet air oxidation can be used to 
oxidize most or all of the carbon portion of the waste. J. R. Heimbuch and 
A. R. Wilhelmi stated in their publication "Wet Air Oxidation--A Treatment 
Means for Aqueous Hazardous Waste Streams", December, 1985, Journal of 
Hazardous Materials, page 192: "A significant advantage of wet air 
oxidation is that there are minimal air pollution problems. Contaminants 
tend to stay in the aqueous phase. The small amount of gas that is 
discharged consists mainly of spent air and carbon dioxide. NOx emissions 
are not observed because nitrogen compounds are converted to ammonia." 
Thus, while wet air oxidation is effective for destroying the carbonaceous 
portion of the waste and converting the nitrogenous portion to ammonia, 
wet air oxidation as currently practiced, does not remove the nitrogen in 
the ammonia present in the aqueous stream. 
In cases of waste streams having a plurality of nitrogen compounds, removal 
of nitrogen is a difficult and expensive task. Prior to the instant 
invention, only bacterial action and incineration were capable of removing 
a plurality of nitrogen compounds from an aqueous waste stream. However, 
neither of these approaches have nitrogen gas as the predominant 
nitrogenous end product and both of these approaches suffer from the 
previously mentioned disadvantages, especially when radioactive waste 
streams are considered. 
The present invention is therefore, directed toward a method of removing a 
plurality of nitrogen containing compounds from an aqueous waste stream 
resulting in release of nitrogen as nitrogen gas without formation of 
nitrous oxides such as NO, NO.sub.2 and N.sub.2 O.sub.4. The method of the 
present invention relies upon aqueous phase reactions at moderate 
temperatures and pressures without the use of a catalyst and without the 
subsequent regeneration and/or disposal of a catalyst in both 
non-radioactive and radioactive waste treatment. 
SUMMARY OF THE INVENTION 
The present invention comprises a method of removing nitrogen by aqueous 
phase reactions from a plurality of compounds containing nitrogen 
including but not limited to nitrates, nitrites, ammonia, amides, amines 
and nitro-organic compounds. Such compounds may be present in 
non-radioactive and radioactive aqueous waste streams and may be treated 
with the method of the present invention resulting in less harmful 
products including nitrogen and oxygen gases, hydroxides, alcohols, and 
hydrocarbons. The hydroxides may be further reacted with carbon dioxide to 
produce solid, dry carbonates. Alcohols and hydrocarbons may be separated 
from the waste stream for future use. 
The method of the present invention can be used alone or in combination 
with existing processes such as wet air oxidation. The combination of 
processes may be performed in a separate reaction vessel or may be 
combined in a single, existing reaction vessel. In the latter embodiment, 
the wet air oxidation may be performed first and then the invention 
disclosed herein applied. 
The method of the present invention comprises the steps of identifying the 
type and concentration of compounds containing nitrogen in the waste 
stream, balancing the oxidized and reduced forms of nitrogen by adding an 
appropriate nitrogen containing reactant such as ammonia or a nitrite or 
nitrate compound, and heating the mixture under pressure to obtain the 
desired reaction. 
Balancing, accomplished by adding a nitrogen compound such as nitric acid 
to a waste stream containing ammonia and amines, will produce water and 
nitrogen and oxygen gases. The addition of a nitrite salt produces similar 
products but with less oxygen gas. 
Heating is required to overcome the activation energy of reactions between 
the balanced nitrogen compounds. Heating may be done before or after the 
balancing step. The balanced and heated mixture is maintained under 
pressure and held at these conditions for sufficient time to allow 
reactions to go to completion. The method can be expanded to include 
further processing of the remaining aqueous products. 
The advantages of the process of the present invention include 1) removal 
of nitrogen from a plurality of compounds containing nitrogen in the 
aqueous phase, 2) reaction products are relatively benign and stable 
allowing recycling or further processing or disposal by conventional 
means, 3) reduced reactor volume as compared with bacterial treatment or 
gas phase treatment of nitrous oxides, 4) lower temperature operation as 
compared with gas phase treatment, 5) faster treatment as compared with 
bacterial treatment, and 6) no catalyst is required. 
The subject matter of the present invention is particularly pointed out and 
distinctly claimed in the concluding portion of this specification. 
However, both the organization and method of operation, together with 
further advantages and objects thereof, may best be understood by 
reference to the following detailed description of the preferred 
embodiment. 
DESCRIPTION OF THE PREFERRED EMBODIMENT 
In the preferred process, nitrogen compounds present in a waste stream such 
as sewage, metal finishing nitrate wastes, and radioactive nitrate wastes, 
are identified and their concentrations determined. Identification and 
determination of concentrations of the nitrogen compounds may comprise one 
or a combination of 1) assessment of prior streams and deduction of 
composition, 2) evaporation and X-ray analysis, 3) direct electrode 
measurement, 4) the Kjeldahl method and variants thereof, 5) infrared, 
visible and ultraviolet spectrometry, 6) gas chromatography, 7) mass 
spectrometry, 8) chemical oxygen demand determination and 9) other 
standard laboratory techniques as required and conventionally practiced. 
When reactants from the group including, but not limited to, nitrate 
salts, nitrite salts, nitric acid, ammonium salts and ammonia are added to 
a nitrogen-containing waste stream, and the mixture heated to a 
predetermined lowest reaction temperature, under sufficient pressure to 
maintain an aqueous phase, and held at these conditions for a 
predetermined time nitrogen is removed as nitrogen gas. The order of the 
balancing and heating steps may be reversed to allow heating first, then 
balancing. In addition to the reactants, pH modifiers such as mineral 
acids, carbon dioxide or organic acids may be used to lower the pH and 
thereby increase the yield of nitrogen gas. 
Reactions used for denitrification include but are not limited to the 
following reaction equations. In the following reactions, M is the symbol 
for a water soluble cation, X is a water soluble anion, and R is a 
covalently bound organic chain or ring. 
______________________________________ 
1. NH.sub.4 - + NO.sub.3 + 
.fwdarw. 
2H.sub.2 O + N.sub.2 + (1/2)O.sub.2 
2. NH.sub.2 CH.sub.2 CO.sub.2 H + 
.fwdarw. 
N.sub.2 + CH.sub.4 + CO.sub.2 + 3O.sub.2 + 
HNO.sub.3 + H.sub.2 O 
2H.sub.2 
3. C.sub.5 H.sub.5 N + 
.fwdarw. 
3N.sub.2 + 5CO.sub.2 + 8H.sub.2 O 
5HNO.sub.3 + 3H.sub.2 O 
4. NH.sub.4 X + MNO.sub.3 
.fwdarw. 
2H.sub.2 O + MX + N.sub.2 + (1/2)O.sub.2 
5. NH.sub.4 X + MNO.sub.2 
.fwdarw. 
2H.sub.2 O + MX + N.sub.2 
6. R--NH.sub.2 + MNO.sub.3 
.fwdarw. 
R--H + MOH + N.sub.2 + O.sub.2 
7. R--NH.sub.2 + MNO.sub.2 
.fwdarw. 
R--H + MOH + N.sub.2 + (1/2)O.sub.2 
8. R--NH.sub.2 + MNO.sub.3 
.fwdarw. 
R--OH + MOH + N.sub.2 + (1/2)O.sub.2 
9. R--NH.sub.2 + MNO.sub.2 
.fwdarw. 
R--OH + MOH + N.sub.2 
10. R--NO + NH.sub.4 X 
.fwdarw. 
R--H + H.sub.2 O + N.sub.2 + HX 
11. R--NO.sub.2 + NH.sub.4 X 
.fwdarw. 
R--H + H.sub.2 O + N.sub.2 + HX + 
(1/2)O.sub.2 
12. R--NO + NH.sub.4 X 
.fwdarw. 
R--OH + N.sub.2 + HX + H.sub.2 
13. R--NO.sub.2 + NH.sub.4 X 
.fwdarw. 
R--OH + H.sub.2 O + N.sub.2 + HX 
14a. 2NH.sub.4 X + 4H.sub.2 O.sub.2 
.fwdarw. 
NH.sub.4 X + HNO.sub.3 + HX + 5H.sub.2 O 
14b. NH.sub.4 X + HNO.sub.3 + 
.fwdarw. 
2HX + N.sub.2 + 7H.sub.2 O + 1/2O.sub.2 
HX + 5H.sub.2 O) 
15a. 2HNO.sub.3 + H.sub.2 S 
.fwdarw. 
NH.sub.4 NO.sub.3 + SO.sub.3 
15b. NH.sub.4 NO.sub.3 
.fwdarw. 
2H.sub.2 O + N.sub.2 + 1/2O.sub.2 
16. 2HNO.sub.3 + 5H.sub.2 S 
.fwdarw. 
N.sub.2 + 5S + 6H.sub.2 O 
______________________________________ 
For example, a waste stream having ammonia, ammonium ion, amines, glycine 
and pyridine can be treated by adding nitric acid resulting in water and 
gaseous nitrogen and oxygen (Equations 1-4,6, and 8). Addition of sodium 
nitrite will give the same products but with less oxygen (Equations 5,7, 
and 9). Balancing R-NO and R-NO.sub.2 with NH.sub.4 X produces nitrogen 
gas and leaves hydrocarbon products that can be treated separately 
(Equations 10-13). Although not shown in the equations amide ions, azo 
compounds, nitro derivatives and amino acids may be treated by addition of 
nitric acid, nitrates or nitrites. In a preferred process, a first 
pre-selected nitrogen containing compound is added to an aqueous stream 
having a second plurality of nitrogen containing compounds. The amount of 
the first pre-selected nitrogen containing compound is equivalent to the 
mole fraction of the second plurality of nitrogen containing compounds 
which can range from TKN (total Kjeldahl nitrogen) detection limits to a 
saturated solution. 
Variations of the basic process are embodied as alternative methods of 
balancing oxidized and reduced forms of nitrogen. A second embodiment of 
the present invention comprises balancing the oxidized and reduced forms 
of nitrogen by adding an appropriate non-nitrogen containing reactant 
(such as hydrogen, hydrogen sulfide, hydrogen peroxide, or potassium 
permangenate, Equations 14-16) in an amount substantially equivalent to a 
half mole fraction of the nitrogen compounds present in the waste stream. 
The addition of sufficient oxidizing or reducing agent to the waste stream 
causes a balance in the oxidized and reduced forms of nitrogen compounds 
and then the desired reactions between the nitrogen compounds will proceed 
and release nitrogen gas and possibly other components such as oxygen gas 
and/or water. 
In the case where the waste water contains an excess of reduced nitrogen 
compounds such as amines or ammonia, oxidizing agents such as air, oxygen, 
hydrogen peroxide or potassium permanganate can be used. Reaction 14 
illustrates an embodiment wherein an aqueous waste stream containing an 
ammonium compound is partially reacted with an oxidant converting some of 
the ammonium ion to nitrous or nitric acid. Further reaction between the 
remaining ammonium ion and the newly created nitrous acid results in 
nitrogen gas, water, oxygen and a hydrogen compound. 
Where waste water contains an excess of oxidized nitrogen compounds, such 
as nitrates or nitrites, hydrogen sulfide can be used as the reducing 
agent. Reactions 15a, 15b and 16 illustrate an embodiment wherein an 
aqueous waste stream containing a nitrate compound is partially reacted 
with a reductant, which may either convert some of the nitrate to ammonium 
nitrate or to sulfur and nitrogen gas. When ammonium nitrate is produced, 
it may be further reacted as in reaction 1 to obtain nitrogen and oxygen 
gases. Whether reactions 15a and b or reaction 16 occurs depends on the 
amount of hydrogen sulfide that is added to the waste stream. 
A variation of this second embodiment comprises splitting an aqueous waste 
stream into a first and second stream of substantially equal portions. The 
reduced nitrogen compounds of the first stream are oxidized into oxidized 
nitrogen compounds such as nitric acid or nitrate or nitrite salts. 
Several strong oxidizers, including but not limited to hydrogen peroxide, 
hydroxyl radical, potassium permanganate, can perform this oxidation. For 
instance, the oxidation of ammonia to nitric acid can be performed with 
hydrogen peroxide at a temperature between 90.degree. C. and 150.degree. 
C. Finally, the oxidized first stream and the untreated second stream are 
combined thereby balancing the oxidized and reduced forms of nitrogen 
compounds. It is recognized that multiple variations may be used without 
departing from the scope of the invention depending on the order of the 
steps of heating to 350.degree. C., splitting the waste stream, and 
heating or cooling 1 stream to between 90.degree. C. and 150.degree. C. 
A third embodiment of the present invention processes streams having carbon 
and nitrogen containing compounds. In this embodiment, the carbon fraction 
is converted to carbon dioxide with wet air oxidation. Next the oxidized 
and reduced forms of nitrogen are balanced by adding an appropriate 
nitrogen containing reactant. The reactant includes but is not limited to, 
nitric acid or ammonia. 
Simply balancing oxidized and reduced forms of nitrogen compounds in an 
aqueous waste stream at ambient conditions is ineffective because of the 
activation energy of the reactions. Therefore, such mixture must be heated 
to a predetermined reaction temperature from about 300.degree. C. to 
600.degree. C. to overcome the activation energy of the reactions, and 
maintained under sufficient pressure to maintain the aqueous stream in an 
aqueous liquid or supercritical phase. It is preferred to use temperatures 
of about 300.degree. C. to 350.degree. C. to reduce the amount of energy 
consumed in the process and it is preferred to use pressures at or above 
saturated vapor conditions at the reaction temperature. Heating is 
accomplished by electricity, steam, radiant and/or convective flame or 
heat transfer oil. The aqueous stream is heated at a pressure sufficient 
to prevent boiling or a pressure equal to or greater than the critical 
pressure of water. For denitrification of NH.sub.4 NO.sub.3, which is 
chemically one of the most difficult of reactions 1-16, the minimum 
reaction temperature is 350.degree. C. Other compounds are believed to 
have similar or lower reaction temperatures. Higher temperatures up to 
600.degree. C. may be used to reduce the time required to complete the 
reactions. Heating to a temperature less than the lowest reaction 
temperature would be ineffective since either no reaction would occur or 
the reaction rate would be too slow for practical use. 
The process of the invention as described in the three embodiments requires 
holding the heated and pressurized conditions for a predetermined time. 
The predetermined time is from about 1 minute to 2 hours, long enough to 
complete the reactions. Since the reactions are exothermic, the reacting 
stream can be passed through a heat exchanger to recover the heat. 
Nitrogen, carbon dioxide and oxygen gas products are released by cooling 
and/or flashing using standard gas and liquid pressure expansion valves. 
The product stream can be mixed with carbon dioxide gas at ambient or 
elevated temperature and pressures to react with any hydroxides present 
and form carbonates according to either of the following equations 17 or 
18. 
______________________________________ 
17. 2MOH + CO.sub.2 
.fwdarw. M.sub.2 CO.sub.3 + H.sub.2 O, or 
18. M(OH).sub.2 + CO.sub.2 
.fwdarw. MCO.sub.3 + H.sub.2 O 
______________________________________

EXAMPLE 1 
An experiment to validate that Reaction 1 takes place in aqueous conditions 
at temperatures at or under 350 degrees centigrade was conducted by adding 
3.34 grams of ammonium nitrate to 300 ml of water and placing the solution 
into a one liter stirred autoclave. The autoclave was then gradually 
heated to 350 degrees centigrade and gas samples were taken at 50 degree 
temperature increments. Pressure in the autoclave was 2400 psi, sufficient 
to maintain the solution in an aqueous phase. Based on the gas 
chromatograph readings, the ammonia reacted with the nitrate at some point 
between 300 and 350 degrees centigrade. 
The percentage of nitrogen in aqueous solution that is converted to 
nitrogen gas is calculated in two steps. The first step is to calculate 
the amount of nitrogen in the vent gas that is actually removed from the 
aqueous solution. The second step is to obtain the ratio of nitrogen gas 
removed to the amount of nitrogen originally present in the aqueous 
solution or convertible nitrogen then multiplying by 100 to obtain the 
percent of nitrogen converted which is termed the denitrification rate. 
In this example, 3.34 grams of aqueous ammonium nitrate contains 1.169 
grams of nitrogen. The volume of gas bled from the autoclave combined with 
the gas in the autoclave amounted to 6.1 liters at a nitrogen volume 
concentration of 15.7% which was 1.197 grams of nitrogen gas. The 
denitrification rate was, therefore, 102% which was essentially complete 
denitrification within experimental error. The gas volume was measured by 
passing the gas in the autoclave through a wet test meter and then adding 
the known volume of the autoclave. While the gas that passed through the 
wet test meter was at room temperature, (approximately 20 degrees 
centigrade), the gas remaining in the autoclave could have been warmer. 
This could introduce a slight error leading to a higher calculated gas 
volume. 
EXAMPLE 2 
An experiment to validate that glycine (NH.sub.2 CH.sub.2 CO.sub.2 H) is 
denitrified (Reaction 2) in aqueous conditions at temperatures at or under 
350.degree. C. was conducted according to the procedure of Example 1. 
Glycine in an amount of 15.8 grams (0.21 gram moles) together with nitric 
acid (HNO.sub.3) in an amount of 49.3 milliliters of 70% concentration 
(0.773 gram moles) are added to 285 grams of water. Since nitric acid is 
in excess, the production of nitrogen gas in Reaction 2 is determined by 
the amount of nitrogen in 0.21 gram moles of glycine and 0.21 gram moles 
of nitric acid, which is 5.90 grams of nitrogen. 
The volume of vent gas from the reactor was 17.7 liters and the nitrogen 
gas fraction was 19.8% which was 4.38 grams of nitrogen gas. The 
denitrification rate was, therefore, 74.2%. 
EXAMPLE 3 
An experiment showing that simply heating an aqueous solution of glycine 
does not result in significant denitrification was conducted according to 
the procedure of Example 1 by adding 15.8 grams of glycine to 300 grams of 
water. 15.8 grams (0.21 gram moles) glycine contain 2.95 grams of 
nitrogen. The volume of vent gas from the reactor was 4.1 liters, and the 
nitrogen gas fraction was 1.5% by volume which was 0.077 grams of nitrogen 
gas. The denitrification rate was, therefore, 2.6%. 
This 2.6% denitrification of glycine achieved by heating in the absence of 
an oxidant (nitric acid) is much less than the 74.2% denitrification 
achieved in the presence of the nitric acid oxidant. 
EXAMPLE 4 
An experiment to validate that pyridine (C.sub.5 H.sub.5 N) is denitrified 
(Reaction 3) in aqueous conditions at temperatures at or under 350.degree. 
C. was conducted according to the procedure of Example 1. Pyridine in an 
amount of 15.8 grams (0.20 gram moles) together with nitric acid 
(HNO.sub.3) in an amount of 56.0 milliliters of 70% concentration (0.878 
gram moles) are added to 285 grams of water. Since pyridine is in excess, 
the production of nitrogen gas in Reaction 3 is determined by the amount 
of nitrogen in 0.878 gram moles of nitric acid and 0.878/5 (0.176 gram 
moles) of pyridine which provides a total of 14.76 grams of nitrogen. 
The volume of vent gas from the reactor was 34.0 liters and the nitrogen 
gas fraction was 27.1% which was 11.5 grams of nitrogen gas. The 
denitrification rate was, therefore, 77.9%. 
EXAMPLE 5 
An experiment showing that simply heating an aqueous solution of pyridine 
does not result in significant denitrification was conducted according to 
the procedure of Example 1. Pyridine in an amount of 15.8 grams was added 
to 285 grams of water. 15.8 grams (0.20 gram moles) of pyridine contain 
2.80 grams of nitrogen. The volume of vent gas from the reactor was 7.5 
liters and the nitrogen gas fraction was 1.4% by volume, which was 0.13 
grams of nitrogen gas. The denitrification rate was, therefore, 4.6%. 
This 4.6% denitrification of pyridine achieved by heating in the absence of 
an oxidant (nitric acid) is much less than the 77.9% achieved in the 
presence of the nitric acid oxidant. 
These examples illustrate the significant denitrification of nitrogen 
compounds that can be achieved through balancing reduced forms of nitrogen 
with an oxidized form such as nitric acid and heating to a reaction 
temperature. However, only example 1 achieves 100% denitrification. The 
other examples may be limited by the carbon. Therefore, in the preferred 
embodiment, carbon may be removed prior to balancing and heating in order 
to achieve 100% denitrification. 
Although there are many methods of denitrification of compounds containing 
nitrogen, only incineration and bacterial action have been alleged to 
remove nitrogen from a plurality of nitrogen compounds. The present 
invention sets forth a third method of denitrification from a plurality of 
compounds containing nitrogen. This method enjoys the advantages of fast 
processing, moderate temperature operation, smaller equipment, and no need 
for addition of a catalyst. The method can be carried out in a vessel 
separate from other waste conversion processes or in the same vessel as 
other waste conversion processes such as wet air oxidation. The products 
of the method are nitrogen, carbon dioxide, methane, and oxygen gas which 
can be released to the atmosphere, hydroxides which can be further 
treated, and alcohols and hydrocarbons which are separable. While a number 
of embodiments of the invention have been disclosed herein, it is to be 
understood that such embodiments are not the only methods of implementing 
the invention, such that the scope of the invention should be determined 
solely by the claims appended hereto.