Nitrate waste streams

The plant disposes of two waste streams gaseous and aqueous. The gaseous emission results from the ammonia and the artunonium nitrate plants. It is fed to an incinerator prior to atmospheric disposal. In the incinerator, ammonia is converted into NOj,. Ehie to more stringent NO regulations, the conqmsition of ammonia in the feed to the incinerator has to be reduced from 0.57 wt% to 0.07 wt%. The lean streams presented in Table 9.5 may be employed to remove ammonia. The main aqueous waste of the process results from the nitric acid plant. Due to its acidic content of nitric acid, it is neutralized with an aqueous ammonia solution before biotreatment. 

The vendor claims that the following metals have been successfully treated to parts per biUion (ppb) and detection limit levels aluminum, arsenic, cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, molybdenum, nickel, selenium, silver, tin, uranium, vanadium, and zinc. The system is also able to remove ammonia, nitrates, phosphates, potassium, fluorides, and sodium. Studies have also been performed using Aqua-Fix to remove radionuchdes such as uranium from waste streams. 

According to the vendor, this project could provide a compact, low-cost reactor to treat aqueous mixed waste streams containing nitrates or nitrites, eliminate the need for chemical reagents, and minimize or eliminate secondary wastes such as nitrous oxide and secondary products such as ammonia, H2, and O2 that are prevalent with other nitrate destruction processes. By removing nitrates and nitrites from waste streams before they are sent to high-temperature thermal destruction and vitrification, production of NO can be decreased with the attendant decrease in off-gas system requirements. Biocatalytic nitrate destruction is applicable to a wide range of aqueous wastes with a highly variable composition. All information is from the vendor and has not been independently verified. 

A VaporSep system recovered approximately 91% of the hydrocarbons from a waste stream of hydrogen, nitrogen, propane, propylene, and water. The capital costs for the system were 2.4 million. By recycling the hydrocarbons and nitrate (permeate and filtrate), the system saved 2.3 million per year (D205549, p. 9). 

The distillation process separates HNO3 from the U-bearlng HNO3-H2SO4. Similarly, HF can be recovered with the HNO3 if it is present in the initial solution. Because nitrates are mobile in the environment, their presence in a final waste form requires that more stringent performance criteria be used to ensure their immobilization. It is desirable to reduce both the volume and quantity of nitrates in the final waste stream discharged from the reclamation process. 

From the chemical manufacturing industry, catalytic cracking and catalytic hydrogenation, gas absorption or scrubbing processes in which desired or waste products are removed from a waste stream, the nitration of benzene and toluene where the reactants have limited mutual solubility, and carbonylation processes using carbon monoxide. 

A third major field of developments will be in co-products. These streams will be treated as product streams rather than as waste streams. Much attention will be paid to product specification and GMP-like production. Also the recovery of better (more suited to specific applications) co-products will be investigated. Examples of this might include the recovery of asparagine, citric acid, low-potassium deproteinized concentrated potato juice, potassium nitrate, food-grade fiber and food-grade protein. 

Utilization of plutonium in early research and commercial orders to fabricate thermal recycle and fast breeder fuels did not coincide in timing with Pu availability from different sources. The plutonium comes mainly from high-exposure light-water reactor fuel reprocessing extended storage of this Pu as a nitrate solution leads to 241 contents up to 3%. For hands-on operation with this material it is necessary to reduce the Am content to about 0.5%. It was also necessary to minimize the liquid waste streams from the plant. In designing a technical-scale process, it was... 

Salts of actinides are very common in waste streams. In particular, nitrates, chlorides, and sulfates are found in tank waste streams that were formed by neutralization of highly acidic solutions at several DOE sites, such as Hanford and Savannah River. The aqueous solubility of these salts is very high, and hence, it is a challenge to stabilize them. As we shall see in case studies, the CBPC matrix has good promise in handling these waste streams. 

Cs, Sr, and Ba are mostly found in salt waste streams as chlorides, nitrates, and sulfates and hence are soluble in water. Even Cs oxide is very soluble. Therefore, they readily react during phosphate stabilization and are chemically immobilized. We shall see in the case studies later in this chapter that such stabilization is very effective in a CBPC matrix. 

Many of the waste streams contain characteristically high concentrations of nonradioactive chlorides, sulfates, and nitrates of K, Na, and Ca, together with radioactive components. Stabilizing these waste streams poses two problems. The first is the large... 

As may be seen from Table 17.8, Cs was added either as CsNOs or CsCl in the first three waste streams, whereas the form of Cs was not known in the last case, but certainly it was soluble because it was detected in wastewater. The TCLP results indicate that Cs, although added as nitrate or some other soluble form, is well immobilized. The LI is not as high as 18 that was reported by Bamba et al. [27] for a glass waste form, but it is certainly higher than the minimum of 6 expected from cement waste forms [28]. 

Unlike Portland cement, the Ceramicrete slurry sets into a hard ceramic even in the presence of salts such as nitrates and chlorides hence, the Ceramicrete process has a great advantage over conventional cement technology with respect to the stabilization of some difficult waste streams, such as those from Hanford and Savannah River tanks. Wagh et al. demonstrated this advantage in several studies, wherein they produced monolithic Ceramicrete solids by using concentrated sodium nitrate and sodium chloride solutions in place of water to stabilize the waste streams. Details of some of these studies may be found in Ref. [21]. 

In the calciner, the liquid waste is pneumatically atomized from three nozzles at 85-140 gph into the heated 6-ft-deep fluidized bed of solidified granular waste at 400°-500°C. The process is endothermic therefore the bed is heated by in-bed combustion of an oxygen-atomized stream of kerosene. The process is started with a bed of granular material such as dolomite, which is replaced by calcine as the operation continues. By preheating the bed with externally-heated fluidizing air to a bed temperature of 360°-400°C, the atomized kerosene will ignite in the presence of a nitrate waste. 

The growth medium includes defined salts, complex nutrients, surfactants, and inducer. The salts are the typical fermentation salts, including potassium phosphate, ammonium nitrate, ammonium sulfate, calcium chloride, and magnesium sulfate [33]. The complex nutrients are most often 5 to 25 g L of corn steep liquor but can also include yeast extract. The surfactants are added to control or suppress foam formation. The surfactants used include commercial antifoams as well as soybean oil or palm oil. The inducers are proprietary to each manufacturer but will contain an inexpensive mixture of soluble and/or insoluble sugars. Some inducers used include milk whey, which contains lactose Solka floe cellulose or, sugar or paper mill waste streams. 

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