Title of Invention

"AN IMPROVED PROCESS FOR ZEOLITE BASED AMMONIA RECOVERY FROM AMMONICAL WASTE"

Abstract

Faujasitic type of zeolites synthesised from flyash having exchange capacity of 420-440 meq/100g have been used for removing ammonium ions from simulated ammonical waste. The faujasitic zeolite have been synthesised using the process, which has been patented nationally and internationally. The recovery of ammonium ion from ammonical waste with subsequent recovery of ammonia gas on heating the ammonium ion exchanged zeolites has great commercial potential. In specific, this process of recovery of ammonia from ammonical waste is of tremendous use to fertilizer industries, wherein ammonical waste is generated in huge quantity. The recovery of ammonia from ammonical waste simultaneously resolves two problems viz.; treatment of ammonical waste, and avoidance of sludges. (as in case conventional recovery method).

Full Text

The present invention relates to closed loop process for recovery of ammonia from ammoniac waste. More specifically, the invent relates to the production of ammonia gas from ammonical waste through the following steps: Zeolite (faujasitic) + Ammonical waste • Zeolite—NH4+HCI 2. Zeolite-NH4 •> Zeolite-H + NH3 3. Zeolite-H + NaCI -> Zeolite-Na + HCI 4. Zeolite-H + NaOH Zeolite-Na + H2O Increasingly stringent water standards have led to re-evaluation of methods for wastewater treatment. Ammonium nitrogen is one such aqueous pollutant, which needs to be appropriately treated prior to discharge into the water bodies because of the eutrophication problem associated with it. In this context sorption of ammonium on zeolites is emerging as a promising methodology. However, commercial and natural zeolites are finding limited application due to prohibitive costs. This bottleneck can be overcome by using inexpensive alternates to commercial and natural zeolites. With this in view, a process has been developed for cost-effective production of zeolites from flyash. The process for production of these flyash based zeolites (FAZs) have been patented nationally and internationaly. These FAZs have been applied for sorption of ammonium ions. Increased awareness and understanding of the deleterious effects of nutrients, released from wastewater treatment facilities into natural water systems has resulted in stringent laws restricting ammonia discharge (Ames, I.L., 1960, The Cation Sieve Properties of Clinoptilofite. The American Mineralogist, Vol. 45). Traditionally, biological systems have provided an economical solution with the retrofitting of biological ammonia removal facilities to existing treatment systems. Whilst often effective, these systems require large land areas, due to the sICwness &f biological conversion of nutrients, thus imposing high capital costs. Physico-chemical wastewater treatment offers a high rate alternative to the conventional biological processes, requiring relatively small land areas for equivalent influent flows. Some innovative techniques are needed to enhance ammonia removal. The conventional air stripping at high pH is technically achievable but, for low concentrations of ammonia in water / wastewater / sewage (typically 25-60 mg NH4-N/I), it is economically prohibitive. A review of published literature revealed past research and development of ammonia adsorption processes using clinoptilolite, a natural zeolite with a high affinity for ammonia (Booker N.A., Cooney E.L. and Priestly A.J., 1996, Ammonia removal from sewage using natural Australian zeolite .Water Science Technology Vol. 34(9) pp. 17-24). Studies have been done all over the world in this field, using clinoptilolite from many different deposits. A high rate process for the removal of soluble ammonia from treated sewage is also being explored using natural zeolite. The system involves the adsorption of the ammonia on natural Australian zeolite, followed by regeneration and reuse of the zeolite. The zeolite is fully regenerable and can exhibit ammonia removal rates commensurate with the high rate of physico-chemical sewage treatment processes. The study reports the most cost-effective way of using zeolite in this process with the most critical part being regeneration of the zeolite (Baykal B., 1998 , Water Science Technology Vol. 37(99) pp. 235-242). The usage of clinoptilolite and multipurpose filters for upgrading effluent ammonia quality under peak loads has also been successfully demonstrated (Centoli R., Sabitino D., Gabotti, C., 1995, Ammonia uptake by zeolite and treatment in USSB reactor of piggerry wastewater, Water Science Technology, Vol. 32(12), pp. 73-81). Ammonia uptake by zeolite and treatment of wastewaters has been illustrated recently (Lahavi O.S., Green N., 1997, Ammonium removal using ion exchange and biological regeneration, Wat. Res., Vol. 32(7), pp. 2019-2028). Though there are several reports available on removal of ammonium ion using natural and synthetic zeolites: their subsequent reuses have been discussed by a very few workers. Also chemical regeneration result in formation of concentrated brine solutions wherein biological regeneration to overcome this problem has been suggested by a few workers. Use of ammonia exchanged zeolite for resource recovery is being proposed nowadays. An innovative approach is being adopted wherein the NHL, exchanged zeolte is being heated to obtain high value based ceramic product viz. mullite. Thus a pollutant viz. ammonium ion, can facilitate, a chemical reaction for the conversion of ammonium zeolite to mullite. The heat treatment of ammonium exchanged zeolite for production of mullite has been explained by an exclusive pathway proposed by Matsumoto et. al (Matsumato T., Goto Y., Urababa K., 1995, Formation process of mullite from NH4 exchanged zeolite-A. Nippon Serami Kkusu Kyokai Gakujutsu Ronbunshi 103(1), 93-95, January). Though several reports are available on use of natural and commercial zeolite for ammonium ion sorption, usage of flyash based faujasitic zeolite for sorption of ammonia has not been reported so far. In the present invention faujasite was prepared by process patented internationally (Rayalu S., Khanna P. & Labhsetwar N., 2000, Process for synthesis of flyash based zeolie-Y, US patent No. 6027, 708, Feb. 22,2000). In this invention, it is proposed to overcome this major drawback of procurement & prohibitive costs associated with commercial zeolite, by replacing it with FAZ. Also, various recovery options other than conventional regeneration option have been studied in detail. The process developed overcomes the drawbacks of conventional process of ammonical waste treatment and simultaneously also overcomes the drawbacks of zeolite based waste treatment. The problems addressed are as follows : - Overcomes the problem of sludge generation associated with conventional process of lime treatment of ammonical wastes - Overcomes the problem of lime handling, dust problem etc. by providing technically non tedious and clean process - Overcomes the \\ reaction conditions (temperature, pressure etc.) associated with conventional processes -Overcomes the adverse environmental effect of sludge handling & disposal associated with conventional process -Provides inexpensive flyash based zeolite as suitable sorbent for ammonium ion exchange thus overcoming the problem of procurement & prohibitive costs associated with commercial zeolite - Overcomes the problem of ammonia loss through conventional process vis-a-vis flyash based zeolite process The main object of the present invention is to provide a process for zeolite based ammonia recovery from wastes which obviates the drawbacks as detailed above. Another object is to use flyash based zeolite which serves as a dual mitigation measure, in which flyash a waste material is being used for production of value added product viz., zeolites which in turn are being used for recovery of ammonia from ammonical wastes with con-comittant detoxification. Accordingly the present invention provides an improved process for zeolite based ammonia recovery from ammonical waste which comprises, i) mixing ammonical waste characterized in that with flyash based zeolite -Y at pH of 6-9 at room temperature resulting in the sorption of ammonium ion on zeolite, ii) stripping the NH4 exchanged zeolite and recovering the ammonium ion from ammonium exchanged zeolite by steam/heat or alkali treatments, iii) exchanging the hydrogen ion from zeolite with sodium chloride or sodium hydroxide and reusing the zeolite. In an embodiment of the invention wherein the flyash based zeolite used may be faujasitic zeolite. In another embodiment of the invention wherein the zeolite used in the process may be synthesised from flyash and sodium hydroxide. In yet another embodiment of the invention wherein the concentration of the ammonical solution was varied from 0.1g/l to 0.5g/l. In still another embodiment of the invention wherein the dose of zeolite-Y was varied from 1 to 7g/l. In further embodiment of the invention wherein the pH may varied from 6.0-9.0. wherein the contact time for exchange is ranging from 5 minutes to 15 minutes. In still another embodiment of the invention wherein the time of contact for steam stripping is ranging from 15 minutes to 1 hr. In yet another embodiment of the invention wherein the NH4-zeolite sample was subjected to heating directly at 100°C for 15 min. In still another embodiment of the invention wherein the NH4-zeolite sample was subjected to exchange with 0.1 N sodium hydroxide. Further embodiment of the invention wherein NH4 zeolite sample was mixed with 0.1N sodium hydroxide and heated from 30 minutes. The FAZ sample was synthesized by fusing flyash with sodium hydroxide. A homogenous fusion mixture was prepared by proper grinding and mixing of flyash and caustic soda in a certain ratio. This mixture was heated to atleast about 500°C, preferably between 550-600°C for about 1 hour. The resultant fused mass was cooled, milled, and mixed thoroughly in distilled water. The slurry was then subjected to aging for about 8 hrs. This amorphous alumino-silicate gel was then subjected to crystallization preferably between 90-110°C for about 10-12 hrs. The solid crystalline product was recovered by filtration and washed thoroughly till the filtrate pH was 10-11 and dried at a temperature of 50-60°C. Characterisation: XRD patterns were recorded using CuKa radiation by Philips model No.PN-1830. Powder XRD analysis was used to monitor zeolite formation process and crystallinity for pre and post ammonia treatment. Flyash based zeolite (FAZ) samples tested for efficiency of ammonia removal includes FAZ as such & washed with water till filtrate pH comes to 9.0. The sample is buffered at pH 9.5 with a borate buffer. It is distilled into a solution of boric acid for titration using H2S04. The In the distillate can be determined titrimetrically with standard H2SO4 and mixed indicators or a pH meter. Distillation unit employed was a simple distillation assembly. Ammonia concentration is calculated as follows: (A-B)x280 C Where, 280 is the factor calculated for 0.02N H2SO4 A = ml of H2SO4 for Blank B = ml of H2SO4 for Sample C = Volume of sample taken (ml) The following examples illustrate the influence of different parameters: 1. Kinetics of ammonium ion sorption for a fixed initial ammonium ion concentration in solution and varying FAZ-Ydose in simulated waste 2. Kinetics of ammonium ion sorption for varying initial ammonium ion concentration and fixed FAZ-Y dose in simulated waste 3. Effect of pH on adsorption systems in simulated waste 4. Recovery of ammonia from NH4 - exchanged zeolite with respect to time and temperature in simulated waste 5. Recovery of ammonia from actual waste The following examples are given by way of illustration of the present invention and therefore should not be construed to limit the scope of the present invention. Example 1 Pre-weighed quantity (1g/l) of FAZ-Y sample was mixed with fixed initial concentration of 0.25 g/l of ammonium chloride solution. The suspension was then stirred vigorously for 15 minutes at room temperature. After filtration the residual ammonia, in the filtrate was determined. From the difference between ammonium ion in the original solution and filtrate, the amount of ammonium iofl sorbet* was calculated. The ammonium ion removal works out to be 30.18%. The results are i u~- presented in Table 1. The same procedure was repeated as in example 1 except for variation in FAZ-Y dose, which was 2 g/l. The ammonium ion removal works out to be 50.89%. The results are presented in Table 1. Example 1b The same procedure was repeated as in example 1 except for variation in FAZ-Y dose, which was taken as 3 g/l. The ammonium ion removal works out to be 64.81%. The results are presented in Table 1 Example 1c The same procedure was repeated as in example 1 except for variation in FAZ-Y dose, which was taken as 4 g/l. The ammonium ion removal works out to be 70.37%. The results are presented in Table! Example 1d The same procedure was repeated as in example 1 except for variation in FAZ-Y dose, which was taken as 5 g/l. The ammonium ion removal works out to be 74.01%. The results are presented in Table 1. Example 1e The same procedure was repeated as in example 1 except for variation in FAZ-Y dose, which was taken as 6 g/l. The ammonium ion removal works out to be 75.0%. The results are presented in Table 1. Example 1f The same procedure was repeated as in example 1 except for variation in FAZ-Y dose, which was taken as 7 g/l. The ammonium ion removal works out to be 76.36%. The results are presented in Table 1. Example 2 The kinetics of ammonia sorption for a fixed FAZ-Y dose (2g/l) with varying concentration was studied and the results are presented in Table 2. PfS-weigrted quantity (2g/l) of FAZ-Y sample was mixed with fixed initial concentration of 0.1 g/l of * ""* ammonium chloride solution. The suspension was then stirred vigorously for 15 minutes at room temperature. After filtration the residual ion, in the filtrate was determined. From the difference between ammonium ion in the original solution and filtrate, the amount of ammonium ion absorbed was calculated. The ammonium ion removal works out to be 71.78%. The results are presented in Pre-weighed quantiV (2g/l) of FAZ-Y sample was mixed with fixed initial concentration of 0.25g/l of ammonium chloride solution. The suspension was then stirred vigorously for 15 minutes at room temperature. After filtration the residual ammonia, in the filtrate was determined. From the difference between ammonium ion in the original solution and filtrate, the amount of ammonium ion observed was calculated. The ammonium ion removal works out to be 64.81%. The results are presented in Table 2. example ZD Pre-weighed quantity (2g/l) of FAZ-Y sample was mixed with fixed initial concentration of 0.5 g/l of ammonium chloride solution. The suspension was then stirred vigorously for 15 minutes at room temperature. After filtration the residual ammonia, in the filtrate was determined. From the difference between ammonium ion in the original solution and filtrate, the amount of ammonium ion observed was calculated. The ammonium ion removal works out to be 36.69%. The results are presented in Table 2. Example 3 The same process was repeated as in example 1 except for carrying out sorption at original pH of 9.0 to 9.5. The suspension was then stirred vigorously for 15 minutes at room temperature. After filtration the residual ammonia, in the filtrate was determined. From the difference between ammonium ion in the original solution and filtrate, the amount of ammonium ion absorbed was calculated. The ammonium ion removal works out to be 52.20%. The results are presented in The same process was repeated as in example 1 except for variation in pH, which was maintained at 6.0 using dil. HCI. The suspension was then stirred vigorously for 15 minutes at room temperature. After filtration the residual ammonia, in the filtrate was determined. From the difference between ammonium ion in the original solution and filtrate, the amount of ammonium ion absorbed was calculated. The ammonium ion removal works out to be 46.92%. The results are presented in Table 3. Example 3b The same process was repeated as in example 1 except for variatbn in pH, which was maintained at pH 7.0 using dil. HCI. The suspension was then stirred vigorously for 15 minutes at room temperature. After filtration the residual ammonia, in the filtrate was determined. From the difference between ammonium ion in the original solution and filtrate, the amount of ammonium ion absorbed was calculated. The ammonium ion removal works out to be 50.89%. The results are presented in Table 3. Example 3c The same process was repeated as in example 1 except for variatbn in pH, which was maintained at 8.0 using dil. HCI. The suspension was then stirred vigorously for 15 minutes at room temperature. After filtration the residual ammonia, in the filtrate was determined. From the difference between ammonium ion in the original solution and filtrate, the amount of ammonium ion absorbed was calculated. The ammonium ion removal works out to be 53.57%. The results are presented in Table 3. EXkmple 4 4 The kinetics of ammonia sorption for a fixed FAZ-Y dose (2g/l) with fixed initial concentration (0.5g/l) of ammonium chloride for various contact time was studied and the results are presented in Table 4 Pre-weighed quantity (2g/l) of FAZ-Y was mixed with fixed initial concentration of 0.5g/l of ammonium chloride solution. The suspension was then stirred vigorously for 5 minutes at room temperature. After filtration the residual ammonia, in the filtrate was determined. From the difference between ammonium ion in the original solution and filtrate, the amount of ammonium ion observed was calculated. The ammonium ion removal works out to be 34.64%. The results are presented in Table 4. Pre-weighed quantity (2g/l) of FAZ-Y was mixed with fixed initial concentration of 0.5g/l of ammonium chloride solution. The suspension was then stirred vigorously for 10 minutes at room temperature. After filtration the residual ammonia, in the filtrate was determined. From the difference between ammonium ion in the original solution and filtrate, the amount of ammonium ion obslPfed was calculated. The ammonium ion removal works out to be 36.27%. The results are presented in Table 4. Example 4b Pre-weighed quantity (2g/l) of FAZ-Y was mixed with fixed initial concentration of 0.5g/l of ammonium chloride solution. The suspension was then stirred vigorously for 15 minutes at room temperature. After filtration the residual ammonia, in the filtrate was determined. From the difference between ammonium ion in the original solution and filtrate, the amount of ammonium ion observed was calculated. The ammonium ion removal works out to be 37.03%. The results are presented in Table 4. Example 5 Pre-weighed quantity (2g/l) of FAZ-Y was mixed with actual waste having ammonium ion concentration of 850 mg/l approximately. The percent recovery of ammonia is 60-75% in comparison with simulated wastes. The results are presented in Table 5. A: Amlakhadi, discharge point (A) B : Amlakhadi, discharge point (B) C : Amlakhadi, discharge point (C) * % removal included on the basis of dose & approx. same initial concentration Pre-weighed quantiV 1g/l of NH4 ion loaded zeolite was mixed with 100 ml of double distilled water and heated for 30 minutes at 100-110°C. The condensate collected was analysed for ammoniom ion. From the difference between the ammoniom ion loaded on zeolite and that obtained in the condensate the percent ammonia recovery was calculated. The recovery of ammonium ion is to the tune of about 82.69%. The results are presented in Table 6. The same process was repeated as in example 6 except for variation in usage of 100 ml of 0.1 N sodium hydroxide solution for exchange. From the difference between the ammonium ion loaded on zeolite and that obtained in the condensate the percent ammonia recovery was calculated. The recovery of ammonium ion is to the tune of about 92.57%. The results are presented in Table 6. The same process was repeated as in example 6 except for mixing with 100 ml of 0.1 N NaOH and heating it for 30 minutes. The suspension was then filtrated. The filtrate was analysed for ammonium ion. The percent recovery of ammonium ion was calculated by the difference between the ammonium ion on zeolite & in the filtrate. The recovery of ammonium ion is to the tune of about 91.14%. The results are presented in Table 6. Example 9 The same process was repeated as in example 6 except for subjecting the NH4 ion loaded zeolite to steam heating and subsequent condensation of the steam to recovery ammonia. The condensate was analysed for ammonium ion. The percent recovery of ammonium ion was calculated by the difference between the ammonium ion on zeolite and in the condensates The recovery of ammonium ion is to the tune of about 82.69%. The results are presented in Table 6. Main advantages of the process : • Provides inexpensive alternate to recovery of ammonia from wastes • Economically viable, technically non-tedious and clean process • Tackles the adverse environmental effects of handling ammonical waste • Resource recovery • Avoidance of sludge generation associated with conventional processes We claim: 1. An improved process for zeolite based ammonia recovery from ammonical waste which comprises, i) mixing ammonical waste characterized in that with flyash based zeolite -Y at pH of 6-9 at room temperature resulting in the sorption of ammonium ion on zeolite, ii) stripping the NH4 exchanged zeolite and recovering the ammonium ion from ammonium exchanged zeolite by steam/heat or alkali treatments, iii) exchanging the hydrogen ion from zeolite with sodium chloride or sodium hydroxide and reusing the zeolite. 2. An improved process as claimed in claim 1 wherein the concentration of the ammonical waste is in the range of 0.1 to 0.85g/l. 3. An improved process as claimed in claims 1 to 2 wherein the dose of zeolite-Y is in the range of 1 to 7g/l. 4. An improved process as claimed in claims 1 to 3 wherein the contact time for exchange is in the range of 5 to 15 minutes. 5. An improved process as claimed in claims 1 to 4 wherein the contact time for steam stripping is in the range of 15 minutes to 1 hr. 6. An improved process as claimed in claims 1 to 5 wherein the ammonia exchanged zeolite is heated directly at 100°C for 15 min. 7. An improved process as claimed in claims 1 to 6 wherein the ammonia exchanged zeolite is exchanged with 0.1 N sodium hydroxide and heated for 30 minutes. 8. An improved process for zeolite based ammonia recovery from ammonical waste substantially as herein described with reference to the examples.

Documents:

279-DEL-2002-Abstract(25-1-2008).pdf

279-del-2002-abstract.pdf

279-DEL-2002-Claims(25-1-2008).pdf

279-DEL-2002-Claims-(13-08-2008).pdf

279-DEL-2002-Claims-(21-08-2008).pdf

279-del-2002-claims.pdf

279-DEL-2002-Correspondence-Others(25-1-2008).pdf

279-DEL-2002-Correspondence-Others-(13-08-2008).pdf

279-DEL-2002-Correspondence-Others-(21-08-2008).pdf

279-del-2002-correspondence-others.pdf

279-DEL-2002-Description (Complete)(25-1-2008).pdf

279-del-2002-description (complete)-13-08-2008.pdf

279-del-2002-description (complete)-21-08-2008.pdf

279-del-2002-description (complete).pdf

279-DEL-2002-Form-1(25-1-2008).pdf

279-del-2002-form-1.pdf

279-del-2002-form-13-(13-08-2008).pdf

279-del-2002-form-18.pdf

279-DEL-2002-Form-2(25-1-2008).pdf

279-del-2002-form-2.pdf

279-DEL-2002-Form-3(25-1-2008).pdf

279-del-2002-form-3.pdf