|Title of Invention||
A PROCESS FOR THE BIOLOGICAL TREATMENT OF AN INDUSTRIAL EFFLUENT
|Abstract||The present invention relates to the biological treatment of effluents or wastewater containing high saline concentrations. The present invention also aims at achieving the reduced levels of Chemical Oxygen Demand (COD) of the treated effluent. The present invention also aims at recovery of the salt present in the effluents to be treated. Accordingly, the present invention encompasses a process for the biological treatment of an industrial effluent including the pharmaceutical industrial effluent having high saline content characterized in that the said biological treatment is carried with a novel microbial preferably bacterial consortium, such as herein described, to achieve the maximum removal that is at least 90 per cent preferably at least 94 percent removal of COD, optionally removing of remaining 6 percent of COD by known technique such as use of activated carbon and further optionally producing or recovering the salt from the effluents to be treated as a by-product by known means.|
|Full Text||FIELD OF THE INVENTION
The present invention relates to the biological treatment of effluents or wastewater containing high saline concentrations. The effluents can be of any industrial origin including the pharma industries. The present invention also aims at achieving the reduced levels of Chemical Oxygen Demand (COD) of the treated effluent. The present invention also aims at, recovery of the salt present in the effluents to be treated. Most importantly the present invention aims at using the novel consortium of microorganisms preferably a bacterial consortium for treating the saline effluents.
DESCRIPTION OF RELATED ART
In a conventional treatment of the effluents a variety of species of microbial origin are being used. But these conventional methods are found to be not satisfactory especially when effluents to be treated have high saline concentrations. The reasons for the failure of treating such effluents were attributed by Woolard and Irvine (1995) to four problems encountered in treating waste containing 0.1 - 5% salt: 1) Conventional treated cultures are sensitive to changes in ionic strength, 2) Increased salt tend to disrupt normal metabolic functions and reduce degradation kinetics, 3) Presence of high concentration of suspended solids and 4) Limited acclimatization from conventional cultures.
However continuous efforts were made in treating the saline effluents. Some of the attempts are herein incorporated for reference.
Lawton and Eggert (1957) found that high salt concentrations affected the fixed-film trickling filter wastewater treatment process but only at salt concentrations of about 2%. One of the main reasons being that conventional microorganisms are sensitive to abrupt ionic changes and in addition they do not tolerate salt concentrations higher than 50 g/L Also, high salt levels disturb the microbial
metabolism with a consequent fall in the removal yields of organic matter. Salt tends to increase the suspended solids (SS) in effluents on account of its lysis effect on many organisms (protozoa, etc.) (Salvado et al 2001).
Extended aeration and classical activated sludge processes also give low removal of COD with NaCI above 2% w/v (Stewart et al. 1962).
Saline wastewater treatment in a rotating bio-contactor (RBC) was also adversely affected by high salt contents (Kinner et al 1962).
Ward and Brock (1978) assumed an inverse relationship between biodegradation of petroleum hydrocarbons and salinity, because enrichment cultures from the Great Salt Lake were not able to grow on mineral oil and to mineralize hexadecane in the presence of salt concentrations above 20%. There are several reports about microorganisms above to oxidize petroleum hydrocarbons even in the presence of 30% NaCI. Among such microorganisms are crude oil degrading Streptomyces albaxialis and an n-alkane degrading member of the Halobacterium group. An approach to extend the capacity of efficient hydrocarbon degraders for biodegradation in saline environments has been performed by impairing the phenotype of osmotolerance to a crude oil-degrading consortium, consisting of four Pseudomonas strains (Kapley et al 1999). Four bacterial strains, belonging to the genera Micrococcus, Pseudomonas and Alcaligenes and tolerating 7.5% NaCI could grow on 0.1% naphthalene and anthracene (Ashok et al. 1995).
Woolard and Irvine (1994) showed a COD (Chemical Oxygen Demand) removal up to 99.5% from a synthetic phenol containing wastewater having a DOC (Dissolved Organic Carbon) of 78 mg/L. However, the work pertains to a synthetic wastewater with low DOC. with a TDS of 150 mg/L. Kargi et al. (2000) showed a COD removal of 96% in the treatment of pickling wastewater between a TDS ranging from 30 to 60 g/L by a activated sludge process. Khannous et al. (2003) showed a COD removal of 88% from a marine-products processing wastewater having a TDS of 20 g/L by activated sludge process.
Woolard and Irvine (1994) demonstrated the applicability of heterotrophic halophilic bacteria for the treatment of hypersaline wastewaters using a novel periodically operated biofilm reactor. Hinteregger and Streichsbier (1997) reported the suitability of a moderately halophilic Halomonas sp. for the biotreatment of saline phenolic wastewater. This strain degraded 0.1 g phenol/L as the sole carbon and energy source in a model industrial saline wastewater containing 1% to 14% NaCI and exhibited optimum growth on phenol at 5% NaCI. Two phenol degrading microorganisms, Candida tropicalis and Alcaligenes faecalis were isolated from Amazonian rain forest soil that had never been contaminated with man-made phenolic compounds. The yeast tolerated higher concentrations of phenol and salt than the bacterium and degraded 1.5 g phenol/L in the presence of 15% salt within 148 h. The bacterium utilized 1.1 g phenol/L in the presence of 5.6% salt within 200 h. An halophilic methane assimilating Methylomicrobium sp. is able to oxidize halogen containing organic compounds such as trichloroethylene in aqueous medium with 2 - 6% salt. A slightly halophilic and alkaliphilic Nacardioides sp. has a broad spectrum of chlorophenol degradation. Halophilic Archaea belonging to the genera Haloarcula, Halobacterium and Haloferax are adapted to high concentrations of halogenated hydrocarbons such as trichlorophenols or insecticides lindane and DDT. Maltseva et al. (1996) isolated the first moderately halophilic Eubacteria able to completely mineralize the herbicide 2,4-D. Rhodococcus rhodochorus strain could grow on 2-hydroxybenzothizole between 1 and 3% salt concentration. A new halotolerant Brevibacterium strain is capable of degrading cyclohexanone and cyclohexanol in the presence of 10% -15% NaCI.
Other salt tolerant microorganisms are Zygosaccharomyces rouxii IFO 1877 and Candida schatauii IFO10258 are used in wastewater treatment.
Kargi and Dincer (1996) examined the treatment ability of Zooglea ramigera, a moderate halophilic bacterial strain at different salt contents using a fed-batch reactor. The COD removal efficiency was 85% at 0.5% salt content. However,
the efficiency dropped significantly with increasing salt contents above 1% and attained nearly 60% at 5% salt content.
Kargi and Dincer in 1998 reported that the high salinity of industrial wastewaters is one of the causes of the difficulty in treating these wastewaters by conventional systems.
Intrasungkha et al (1999) reported that SBR achieved good biological nutrient removal when salinity levels in the influent were low at 0.03% to 0.2% (NaCI) but showed difficulties with biological phosphorus removal at salinity levels of 0.5% with seafood processing wastewater. Kargi and Uygur (2005) used a 4-step SBR for nutrient removal at different salt (NaCI) concentrations by using Halobacter added activated sludge. At salt contents of 5 %, nearly 73% of COD, 51% of NH4-N and 31% of PO4 were removed compared to normal SBR where 47% COD, 36% NH4-N and 21% PO4-P was removed without Halobacter.
Hinteregger and Streichsbier (1999) studied the decomposition of phenol in a saline medium by a species of Halomonas sp. under optimal growth conditions between 30 to 50 g/L NaCI, the removal of 0.1/L of phenol was complete after 13 hours.
Kargi and Dincer (2000) observed that Halobacter halobium produced a COD removal of 85% in an activated sludge process on fed batch mode in 9 hours from a synthetic saline wastewater containing 3-5% salt content. Uygur and Kargi (2004) showed a drop in the COD removal from 96% to 32% when salt content increased from 0 to 6% in a sequencing batch reactor. The rate of COD, NH4-N, PO4-P removal decreased with increasing salt concentration.
Kubo et al. (2001) reported the removal of 60 to 70% of COD from a neutralized pickled-plum wastewater at 150 g/L NaCI in an aeration tank in 7 days. The limitations of the process are that the wastewater was neutralized from a pH of 2.5 and residence time was 7 days.
Kubo et al. (2001) uued two salt tolerant bacteria such as Staphylococcus sp. and Bacillus cereusm an activated sludge process.
Khannous et al. (2003) showed a COD removal of 88% from a marine-products processing wastewater having a TDS of 20 g/L by activated sludge process.
Reference may be made to another study using a bench scale SBR inoculated with halophilic sediments in order to treat an effluent from the tartar industry containing a COD of 4,340 mg/L and salts at 120 g/L (Lefebvre et al. 2004). The microorganisms were able to treat carbon and nitrogen; provided the pH in the reactor was neutralized with phosphoric acid. Soluble COD and TKN removal attained 83% and 72% respectively.
Little research has been done at pilot scale and most of the studies have been the use of synthetic effluents and not actual wastewaters. Panswad and Anan (1996) obtained 71% chemical oxygen demand removal using an anaerobic/anoxic/aerobic process and a synthetic wastewater containing 3% salt. Dincer and Kargi (2001) treated a synthetic effluent with increasing salt concentrations (0 - 10%) using aerobic biological disc system and could get more than 80% COD removal efficiency at 50 g/L. Moon et al. (2002) studied the COD removal in SBR using a synthetic fish meal wastewater containing a COD between 1,000 to 1,200 mg/L at a NaCI concentration of 5,000 to 10,000 mg/L. The COD removal efficiency was 92.9% at 3,000 mg/L NaCI concentration and 87.9% at 10,000 mg/L NaCI concentration. The limitations of the process are that the study revealed that an increased NaCI level (above 10,000 mg/L) affected the COD removal efficiency and the system was operated at a maximum COD of 1200 mg/L with synthetic wastewater. Lefebvre et al (2005) have shown the treatment of tannery soak liquor in an aerobic SBR at a COD of 1.5 - 3.6 g/L and TDS range of 21 - 57 g/L. The COD removal was 92 - 96%. Gharsallah et al. (2002) showed that a continuous fixed biofilm reactor at different organic loading rates of 250 and 1000 dm3 day”1, there was a COD removal of 92.5% and 87%
respectively at a salt concentration of 30 mg/L with saline wastewater from marine-products processing industry.
SUMMARY OF THE INVENTION
The first object of the invention is to treat the effluents having high saline content wherein the effluent includes effluents of pharma industry.
The next object of the present invention is towards removal of COD at least to an extent of 90 per cent.
The next object of the invention is to provide a novel microbial preferably bacterial consortium to treat the industrial effluent having high saline content.
The next object of the present invention is to use a novel bacterial consortium preferably from Bacillus species to treat the effluents having high saline content and to use the new bacterial consortium of the present invention, namely [AUESNVBTBAC001] for the purpose.
The next object of the present invention is to provide either batch process or continuous process or the use of simultaneous or concurrent processes wherein the bacterial consortium is used to treat the industrial effluents.
The next object of the invention is to recover the salt from the effluent for the uses that are better known.
The next object of the invention is to reuse the treated wastewater or effluent for the reasons better known.
The present invention aims at treating the effluents or wastewater having high saline content by using a novel bacterial consortium, such as herein described.
The said process of treatment is applicable for both the batch and continuous process. As a result of this process at least 90 percent, preferably 94 percent most preferably 100 per cent of removal of COD is achieved. Optionally from this process the salt is recovered.
Accordingly, the present invention encompasses a process for the biological treatment of an industrial effluent including the pharma industrial effluent having high saline content characterized in that the said biological treatment is carried with a novel microbial preferably bacterial consortium [AUESNVBTBAC001], such as herein described, to achieve the maximum removal that is at least 90 per cent preferably at least 94 percent removal of COD, optionally removing of remaining 6 percent of COD by known technique such as use of activated carbon and further optionally producing or recovering the salt from the effluents to be treated as a by¬product by known means.
These and other objects, features and advantages of the present invention will become more apparent from the ensuing detailed description of the invention taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 indicates the process flow diagram showing the removal of organics from process wastewater in a continuous flow reactor.
Figure 2 indicates the process flow diagram showing the recovery of sodium chloride from process wastewater in a continuous flow reactor.
Figure 3 indicates the process flow diagram showing the recovery of sodium chloride from process wastewater in a batch reactor.
DETAILED DESCRIPTION OF THE INVENTION
The preferred embodiments of the present invention will now be explained with reference to the accompanying drawings. It should be understood however that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. The following description and drawings are not to be construed as limiting the invention and numerous specific details are described to provide a thorough understanding of the present invention, as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention. However in certain instances, well-known or conventional details are not described in order not to unnecessarily obscure the present invention in detail.
The present invention relates to a process for the biological treatment of pharmaceutical wastewater containing high dissolved solids. The present invention provides a comprehensive treatment of high TDS pharmaceutical wastewater which envisages
1) biological removal of 94 % of COD
2) complete removal of COD
3) production of 4-6 g/L of MLSS in the batch process and 4 g/L in the continuous flow process
4) removal of 90 % of nitrogen from wastewater and
5) recovery of sodium chloride
Further, the present invention provides the biological treatment whereby the efficient removal of COD and DOC is up to 94 % in the presence of 50 - 60 g/L of sodium chloride by using a consortium of bacterial strains. The biological treatment is provided with extended aeration regime for the production of 4 - 6 g/L of MLSS in the batch process and 4 g/L in the continuous flow process with a F/M ratio of 0.04/d. The treatment plant operated on continuous mode efficiently removed the COD up to 95 %. The wastewater contained a Chemical Oxygen
Demand from 4,200 to 5,400 mg/L and dissolved solids in the range of 45,000 to 67,000 mg/L, nitrogen between 200 and 240 mg/L and phosphate in the range of 45 to 60 ug/L.
The principle underlying the invention is the removal of COD up to 94 % and activated adsorption for the removal of remaining COD for reuse of NaCI solution. The remaining 6 % of COD is removed by activated carbon, and NaCI to the extent of 4.5 to 6 % is recovered.
Further, the invention provides a biological treatment for the removal of organics, a process for zero discharge of effluent and to enable cost savings by avoiding the use of single or multiple power driven evaporators for the burning of high strength organic and salt laden wastewater.
The invention further provides for the high strength organic and salty wastewater to be biologically treated instead of the conventional use of solar evaporation or evaporation through the use of multiple evaporator without treatment. This ensures the illegal disposal of the wastewater into surface waters for want of a suitable treatment method.
Further this invention involves the process wherein the wastewater is treated by using a consortium of bacteria named Bacillus subtilis, B. licheniformis, B. pumilus and B. littoralis. The special bacterial consortium of the present invention, namely [AUESNVBTBAC001], is used for maximal removal of organics in the process wastewater.
Chemical Oxygen Demand
The chemical oxygen demand is a measure of the total amount of chemically oxidizable material present in the water. Oxidation of most of the organics is achieved irrespective to whether the organic matter can be degraded biologically.
Outline of effluent treatment plant
In general principles are that an efficient effluent treatment plant should reduce organic matter, suspended matter and potential inorganic nutrients thus reducing the pollution effects. We can identify five key stages in the treatment of wastewater. They are:
• Preliminary treatment mainly to remove grit, heavy solids and floating debris.
• Primary treatment to remove a substantial portion of the suspended matter.
• Secondary treatment by aerobic or anaerobic treatment in which oxidizable organic matter is removed by microorganisms.
• Tertiary treatment to remove specific materials ex. Ammonia, phosphates.
• Sludge treatment designed to render safe and dispose of organic materials and organisms sedimented in other stages of the treatment processes.
During the batch process, the wastewater was neutralized to required pH 7.4. Then the wastewater is subjected to aerobic treatment by an extended aeration system by the activity of bacterial consortium. The COD in the wastewater was removed to the extent of 90% and produced an MLSS of 4-6 g/L. In the next step, the treated wastewater from the aeration tank was settled for the removal of suspended matter. The clear liquid was subjected to activated carbon adsorption on granular activated carbon to remove the remaining organics and the final effluent was used for the recovery of sodium chloride by solar evaporation.
During the continuous process, the wastewater was neutralized to required pH 7.4. Then the wastewater is subjected to aerobic treatment by an extended aeration system by the activity of bacterial consortium. Diffusers are used for
providing the required oxygen. The COD in the wastewater was removed to the extent of 94% and the MLSS was maintained at 4 g/L. The approximate hydraulic retention time was 4.7 days and the food to microorganisms ratio was 0.04/d. In the next step, the treated wastewater overflows from the aeration tank to the sedimentation tank where the solids were settled for the removal of suspended matter. Part of the sludge from the sedimentation tank was recycled into the aeration tank and the remaining sludge was subjected to composting. The clear liquid was subjected to activated carbon adsorption on granular activated carbon to remove the remaining organics. Approximately 80% of the wastewater was available as final effluent. The final effluent was subjected to solar evaporation for the recovery of sodium chloride (4- 6%).
Food to Microorganisms (F/M ratio)
Food to Microorganisms means the amount of substrate (biodegradable organic matter) available to bacteria for oxidizing the same.
COD test is used to measure the content of organic matter of both wastewater and natural waters.
Dincer and Kargi (2001) studied the effect of COD concentration or COD loading rate of 5,000 mg/L. The removal efficiency was 93% at 1% salt and the efficiency dropped to 83% at 5% salt concentration.
Kubo et al. (2001) used two salt tolerant bacteria in an activated sludge process with pickled plum wastewater treatment and the COD removal was from 60 to 70% in 7 days residence time.
Kargi and Uygur (1996) tested the biological treatment of a synthetic (0 - 5% NaCI) wastewater containing diluted molasses and urea in an aerated percolator column with immobilized cells on ceramic particles. High COD removal efficiencies at salt concentrations above 4% were obtained with halophilic
Halobacter halobium, whereas salt tolerant microorganisms from activated sludge were more active at low salt concentrations (1 - 2%). Anaerobic treatment of fishery wastewater from te Chilean fishmeal industry, which as a high salt content and high organic load (4-6 kg COD/m3) was performed using a marine sediment inoculum with methanogenic/sulphate reducing activity.
Borja et al (1995) investigated the influence of the organic loading rate ranging from 2.5 to 25 g CODdrrf3 day*1 on soluble COD removal efficiency in a down-flow fixed bed reactor applied to abattoir wastewaters. They observed that the lowest COD removals were obtained with the most concentrated feed (COD=28.7 g dm”
Bories et al (1988) studied the effect of organic volumetric loading rate on COD removal efficiency in a down flow anaerobic fixed-bed applied to distillery waste at loading rates in the range of 1-20 g COD dm”3 day”1 and reported removal efficiencies of between 60 and 70%.
Types of bacteria used in the Treatment of Effluents
In general the bacteria in the activated sludge process include members of the genera Pseudomonas, Zoogloea, Achromobacter, Flavobacterium, Nocardia, Bdellovibrio, Mycobacterium and the two most common nitrifying bacteria Nitrosomonas and Nitrobacter. Additionally various filamentous forms such as Sphaerotilus, Beggiatoa, Thiothrix, Lecicothrix and Geotrichum may also be present. Also other bacteria such as Sarcina, Streptococcus, Escherichia, Salmonella, Shigella, Aerobacter, Staphylococcus, Vibrio and Desulphovibrio are reported. Other forms of bacteria detected in wastewater treatment plants are Nosticola limicola, Microthrix parvicella, Hypomicrobium denitrificans, Hypomicrobium indicum, Marinosulfonomonas methylotroha, Nitrosomonas oligotropha, and Nitrospira sp. Rajeshkumar and Jayachandran (2004) have shown that Sporolactobacillus sp., Citrobacter sp., Pseudomonas sp.} Alcaligenes sp., Bacillus sp., Staphyloccous sp. and Proteus sp. in dairy wastewater
treatment. The dairy wastewater having a COD of 5095 mg/L was treated to the extent of 62% in 5 d^ys by Alcaligenes sp.
While the bacteria are the microorganisms that actually degrade the organic waste in the influent, the metabolic activities of other microorganisms are also important in the activated sludge system. For example protozoa and rotifera act as effluent polishers. Protozoa consume dispersed bacteria that have not flocculated, and rotifers consume small biological floe particles that have not settled.
Although it is important that bacteria decompose the organic waste as quickly as possible, it is also important that they form a satisfactory floe, which is a prerequisite for the effective separation of the biological solids in the settling unit. It has been observed that as the mean cell residence time of the cells in the system is increased, the settling characteristics of the biological floe are enhanced. For domestic wastes, the mean cell residence times on the order of 3 to 4 d are required to achieve effective settling.
Under Halophilic condition
Microorganisms requiring salt for growth are referred to as halophiles where microorganisms that are able to grow in the absence as well as in the presence of salt are designated halo-tolerant. Extreme halophiles require generally at least 1 M NaCI (approx. 6%) for growth, and grow optimally at NaCI concentrations above 3 M. Halophilic archaea maintain an osmotic balance with the hypersaline environment by accumulating high salt concentrations, which requires salt adaptation of the intracellular enzymes. The use of microorganisms above to degrade organic wastes in the presence of salt could prevent costly dilution to lower the salinity, or the removal of salt by reverse osmosis, ion exchange or electrodialysis before biological treatment.
Another source of contaminants are organic solvents. Aerobic transformations of formaldehyde by a moderately halophilic Eubacterium in presence of 1-20% salt
was described by Oren et al (1992). Mineralization fo N,N-dimethylformamide by a bacterial consortia was observed at various salt (0.2% - 7% NaCI) conditions.
Steps involved in the treatment of effluent:
Neutralization: The process wastewater from the process is conveyed through a pipeline to the neutralization tank where the wastewater is neutralized to adjust the pH of the wastewater by the addition of sodium hydroxide. The pH of the wastewater is brought to 7.4.
Aeration Tank: The wastewater is brought to the aeration tank by gravity flow. The system is operated like an extended aeration system of activated sludge process. Due to aeration the solids in the aeration tank is kept in suspension. A special microbial consortium is used in the aeration tank to oxidize the organics in the wastewater. The aeration is provided through diffused aeration system. During this process adsorption, flocculation and oxidation of organic matter occurs. The Food to Microorganisms ratio achieved was 0.04/d. The diffused aeration serves to maintain the mixed liquor in a completely mixed regime. The Mixed Liquor Suspended Solids (MLSS) and Mixed Liquid Volatile Suspended Solids (MLVSS) in the aeration tank and the overflow from the secondary settling tank were determined in the laboratory (Lab analysis). The MLSS in the aeration tank is maintained at 4 g/L. Necessary anti-foaming agents could be added to control the foam developing in the aeration tank.
Sedimentation: The treated wastewater is conveyed to the settling tank where the cells are separated from the treated wastewater. A portion of the settled cells is recycled to maintain the desired concentration of organisms in the reactor and a portion is wasted.
Granular Activated Carbon (GAC): Granular activated carbon is used to adsorb the residual organics present in the wastewater.
Final Effluent: The treated wastewater is called as the final effluent. This contained 0 mg/L COD.
Solar Evaporation: The treated effluent was exposed to solar radiation for evaporation to recover the sodjum chloride. The effluent is rich in sodium chloride to the extent of 4 to 6.5% which almost double the concentration we find in sea water.
The settled sludge in the secondary settling tank is pumped to solar drying beds where the sludge is separated and the filtered effluent is passed into the aeration tank. The sludge which is mostly the biomass from the aeration tank is composted for use as manure.
The special bacterial consortium produces a suspended solid up to 6 g/L in terms of MLSS concentration.
MLSS produced is sedimented under high saline environment to produce sludge of 5 to 6 g/L.
The treated wastewater is rich in sodium chloride to the extent of 4 to 6.5% as a value by-product.
The following examples pertaining to batch studies are given by way of illustrating the present invention and therefore should not be construed to limit the scope of the present invention.
The process wastewater had the following composition: COD - 4,200-5,400 mg/L TDS—45,000-67,000 mg/L; TSS-840-900 mg/L; Nitrogen - 220-240 mg/L; Phosphate -45 - 60 ug/L. The process wastewater was treated in lab scale batch reactor with the help of the bacterial consortium. The COD removal efficiency was
90%. There was np external .addition of nitrogen and phosphate and the batch study was carried out under hypersaline environment.
In another experiment the process wastewater with the same composition was treated with the addition of ammonium nitrate as nitrogen supplement at 0.5% in the presence of the special bacterial consortium. The total COD removal efficiency was determined. The COD removal was 95% in the presence of ammonium nitrate as well as in the absence of ammonium nitrate.
The batch study was conducted with raw wastewater, 60% and 30% concentration by dilution. After 6 days, the COD removal was 68% in raw wastewater, 72% removal at 60% concentration and 56% at 30% concentration of wastewater.
In another experiment, the raw wastewater, 60% and 30% concentration of wastewater was treated with bacterial consortium and the total protein present in the biomass was determined. After 6 days, the total protein production in the bacterial biomass was 58 mg/mL in raw wastewater, 18 ug/mL at 60% concentration and 7 ug/mL at 30% concentration of wastewater.
The process provides for zero discharge of effluent for the reuse of the effluent containing 4 to 6.5% sodium chloride.
The following examples are given by way of illustrating the present invention in a continuous flow reactor and therefore should not be construed to limit the scope of the present invention.
The process wastewater had the following composition: COD— 4,200 - 5,400 mg/L; TDS—45,000-67,000 mg/L; TSS-840-900 mg/L; Nitrogen - 220-240 mg/L; Phosphate -45 - 60 ug/L. The process wastewater was treated by extended aeration process with the help of a bacterial consortium. The COD removal efficiency was 94%. There was no external addition of nitrogen supplement or phosphate to the process.
The process wastewater with the same composition was treated with the bacterial consortium in a continuous flow reactor and the amount of MLSS produced during the process was determined.
In another experiment the consortium of bacteria used in the treatment process was analyzed for individual bacterial strains. They were Bacillus subtilis, S. licheniformis, B. pumilus and B. littoralis.
The treatment process provide for the removal of balance of 6% COD by granulated activated carbon for complete removal of COD from.the process wastewater.
The process provides for zero discharge of effluent for the reuse of the effluent containing 4 to 6.5% sodium chloride.
The following examples illustrate in brief the batch and continuous process methods.
The process wastewater had a COD of 5400 mg/L. The wastewater was neutralized to pH 7.4. The neutralized wastewater was taken in a reactor for adding the bacterial consortium and the bacterial consortium was added. Diffused aeration was provided to maintain the DO. At the end of the batch treatment, the wastewater was settled and the supernatant was analysed for COD. Nearly 90 % of COD was removed and the balance 10 % of COD was removed by passing the effluent through a granular activated carbon filter to remove the remaining COD.
The process wastewater had a COD of 5400 mg/L. The wastewater was neutralized to pH 7.4 and was pumped to aeration tank where the bacterial consortium was added. Aeration was provided by diffused aeration system to main the DO. The MLSS of the aeration tank was maintained at 4 g/L. The overflow from the aeration tank showed a COD 500 mg/L which amounted to a COD removal of 94 %. The overflow from the sedimentation tank was passed through a granular activated carbon and the effluent had 0 mg/L of COD. The final effluent was subjected to solar evaporation.
It will also be obvious to those skilled in the art that other methods and apparatuses can be derived from the combinations of the various methods and apparatuses of the present invention as taught by the description and the accompanying drawings and these shall also be considered within the scope of
the present invention. Further, description of such combinations and variations is therefore omitted above
Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are possible and are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart there from.
GLOSSARY OF TERMS AND DEFINITIONS THEREOF
TDS-Total Dissolved Solids
TSS - Total Suspended Solids
COD - Chemical Oxygen Demand
BOD - Biochemical Oxygen Demand
DOC - Dissolved Organic Carbon
MLSS - Mixed Liquid Suspended Solids
MLVSS - Mixed Liquid Volatile Suspended Solids
SBR - Sequencing Batch Reactor
TKN -Total Kjeldha! Nitrogen
VSS - Volatile Suspended Solids
RBC - Rotating bio - contactor
1. A process for the biological treatment of an industrial effluent including the pharmaceutical industrial effluent having high saline content characterized in that the said biological treatment is carried with a novel microbial preferably bacterial consortium, such as herein described, to achieve the maximum removal that is at least 90 per cent preferably at least 94 percent removal of COD, optionally removing of remaining 6 percent of COD by known technique such as use of activated carbon and further optionally producing or recovering the salt from the effluents to be treated as a by-product by known means.
2. The process as claimed in claim 1 wherein the consortium is a bacterial consortium selected from Bacillus species.
3. The process as claimed in claim 2 wherein the Bacillus consortium comprising Bacillus subtilis, B. licheniformis, B. pumilus and B. littoralis.
4. The process as claimed in the preceding claims wherein COD is 100 per cent removed.
5. The process as claimed in the preceding claims wherein salt is recovered.
6. The process as claimed in claim 1 wherein the wastewater to be treated comprises:
a. COD - 4200 to 5400mg/L
b. TDS - 30,500 to 70,000 mg/L most preferably 45,000 to 67,000 mg/L
c. TSS - 840 to 900 mg/L
d. Nitrogen- 220 to 240 mg/L
e. Phosphate - 45 to 60 mg/L
7. The process as claimed in claim 1 wherein:
a. MLSS - Mixed Liquor Suspended Solids is produced preferably 4-6 g/L of MLSS in the batch process and 4 g/L in the continuous flow process is produced with a F/M ratio of 0.04 d/L;
b. At least 90% of nitrogen is removed; and
c. Salt is recovered
8. A novel and synergistic bacterial consortium comprising Bacillus subtilis, B. licheniformis, B. pumilus and B. littoralis capable of treating an effluent having high saline content.
9. A treated effluent as obtained by the process as described herein.
|Indian Patent Application Number||1675/CHE/2006|
|PG Journal Number||2/2010|
|Date of Filing||13-Sep-2006|
|Name of Patentee||ANNA UNIVERSITY,|
|Applicant Address||GUINDY CAMPUS, SARDAR PATEL ROAD, CHENNAI ,|
|PCT International Classification Number||C02F1/00|
|PCT International Application Number||N/A|
|PCT International Filing date|