Title of Invention

"A BIOMETHANATION PLANT AND A PROCESS FOR TREATMENT OF SPENT WASH USING THE BIOMENTHANATION PLANT"

Abstract

A Biomethanation Plant comprising of desuldge means as herein described desuldge loops providing at the bottom in each compartment, said means having holes on rooftop for monitoring level of sludge, means are provided for improving gaseration efficiency, a digester having multi compartment for multistage biodegradation with additional stream controllers between partition walls, said stream controllers having opening at the bottom, a spent wash feed means provided with valves on branch pipe lines on roof top with cleaning mechanism, a complete liquid mixing means provided, a gas pressure releaser installed on roof top with cleaning mechanis, a complete liquid mixing means provided, a gas pressure releaser installed on rooftop near gas dome for releasing high pressure inside digester.

Full Text

Field of the invention This invention relates to an improved process and plant for the treatment of an effluent namely, the spent was from distillery. This particularly relates to an improved method of reduction of Chemical Oxygen Demand (COD), Biological Oxygen Demand, Total Dissolved Solids (TDS) and Total Suspended Solids (TSS) from the spent wash along with high biogas production by thermophilic biomenthanation. DESCRIPTION OF RELATED ART Background and Prior Art References Most of the distilleries in India use molasses as the raw material for fermentation to produce alcohol. Molasses contains fermentable sugar, which is utilized for conversion into alcohol during fermentation. The balance organics and inorganic chemicals form constituents of the effluent, which is commonly known as Spend Wash. The spent wash effluent discharged from distillation unit is highly polluted and it contains BOD 50, 000 to 60,000 mg/I as well as COD 100,000 to 160,000, which is one of the worst industrial effluents all over the world. The spent wash is characterized by its colour, high temperature, low pH, high ash content and contains high percentage of dissolved organic and inorganic matter. Indian spent wash contains very high accounts of potassium, calcium, chloride, sulphate and BOD. Alcohol production by the Indian distilleries bears immense significance, as it is the basic chemical for rapidly advancing chemical industry and a readily available source of energy. Therefore, in the present scenario as well as for future, demand for alcohol in increasing day by day. The proportion of spent wash is nearly 12 to 15 times the total alcohol production. This massive quantity of effluents, if disposed untreated can cause considerable stress on water sources leading to widespread damage to aquatic life. The technology for treatment of such a wastewater is of prime concern. Most efficient way to treat the distillery spent wash is by anaerobic technology (i.e. Aerobic Lagoon, Anaerobic Digester, Anaerobic Contact Filter etc.) and get the valuable Biogas as a byproduct which can be used as energy as every day our natural resources are depleting, which gives an urgent attention to conserve our natural resources. Potential of Bioenergy The total effluent generated by Indian distilleries in a year has a very high potential of producing biogas. Biomethanation process (anerobic digestion) is, in other words, named as Bio-gas production plant due to the fact that input spent wash having organic pollutant is biodegreaded and simultaneously biodegraded organic substances are converted to methane rich biogas in their gasification stage, which is utilized as boiler fuel for steam generation or fuel for power generation plants. This biogas normally contains 55 to 65% methane gas, which is well-recognized fuel gas with minimum air pollution potential. Pollution from Distilleries Therefore, despite, stringent standards imposed on effluent quality, the untreated or partially treated effluents very often find access to watercourses. The spreading of effluents along the marginal land surrounding distilleries is a common site. The retention of effluents in open anaerobic lagoons and solar drying ditches is responsible for the odour one encounters while passing through a distillery. Thus distilleries in India have also been responsible the pollution of the air, water and land. The distillery wastewater poses a serious threat to water quality in several regions of country. Lowering of pH value of the streams, increasing organic load depletion of oxygen content, destruction of aquatic life and bad smell are some of the major pollution problems due to distillery wastewater. High BOD poses depletion of dissolves oxygen and proves very harmful to aquatic life. Ground water contamination by effluent with high BOD and salt content near the lagoon side in the most of the distilleries has been reported widely. Treatment of Distillery Effluent To meet the requirement as per the minimum National standards (MINAS) issued by the Govertmient of India for different industries taking into account the characteristics of effluent, the effluents should have pH between 5.5 to 9 suspended solids 100 mg/lit and maximum BOD level of 30 mg/lit for disposal into inland surface waters and 100 mg/litfor disposal on land. To achieve this distilleries in India are adopting primary treatment of spent wash by biomethanation plants followed by secondary and tertiary treatment. Only the biological treatment is most often found to be effective which are amply demonstrated by adoption of these methods by all the distilleries. Severe water pollution problems in the nearby rivers and lakes are frequently encountered as the partially treated effluents find assess to water bodies. Recent Advances in Distillery Effluent Treatment The recent treatment methods include anaerobic digesters, which is not only substantially reduce the organic load of the effluent but also produce methane gas. The gas is used, as a fuel to compensate the energy needs of the industry. Since the conventional aerobic processess for primary treatment of distillery waste are not cost effective and require large land area, the thrust has been mainly on anaerobic processes as these have dual advantages of pollution control and production of fuel. A general estimate suggest that the cost of an result of substantial saving of coal and other fiiels. The anaerobic process offers a number of advantages over other treatment methods, as follows. The process can accept high organic loading rates )OLRs) since oxygen transfer is not a limiting factor. The process produces a useful product viz, methane gas. The available energy in the form of methane is normally in excess of that needed to oeprate the systems. Low synthesis rate yields low residual sludge and nutrient required low (N & P). Active anaerobic biomass can be preserved unfed for several months and no offensive odour exists since the process by its very nature is totally enclosed. The intermediate and end products offer measurable and identifiable control on biological overloading. Biomethanation Plant ( Anaerobic Digesters ) Biomethanation is the bacterial fermentation of organic material. This produces biogas, which is typically made up of 55-65% methane with remaining constituent carbon dioxide with traces of nitrogen, sulphur componds, volatile organic compounds and ammonia. (Digestion) bacteria have a temperature range in which they are most productive in terms of production rates, growth rates and substrate degration performance. The several groups of bacteria involved in anaerobic digestion all have (slightly) different temperature optimums. This resuhs in two main temperature ranges in which digestion usually can be performed optimally and most economically. Based on operating temperature range, there are two types of Biomethanation process. Mesophilic Biomethanation: The operating temperature range is 35-39 degree C and the spent wash remains in the digester typically for 15-20 days. Thermophilic digestion : The operating temperature range is 50 to 55 degree C and the residence time is typically 10-12 days. Thermophilic digestion systems offer higher methane production, faster throughput. Mesophilic and thermophilic temperatures are preferred as a higher loading rate of organic materials can be processed and, because a shorter hydraulic retention time (HRT) is assoicated with higher temperatures, increased outputs for a given digester capacity result. Thermophillic Biomethanation plants AQUA TECHNOS ASIA CO LTD, a Thailand based Japanese engineering company engaged in mainly pollution control business had developed biotechnology by thermophilic biomethanation system in cooperation with Suiwa Kogiken Company Ltd, Japan based on technolgy originally develoed by Institute of Industrial technolgoy, Ministry of Industry, Japan, which is different a lot from mesophilic system. Thereafter several commercial size plants were set up and operated successfully in Thailand. In 1986, first biomethanation plant in India was set up to operate in Ankleshwar, Gujarat. Since them, more than 20 No of thermophilic biomethanation plants have been constructed with steady base in the period of more than decade and succeeded to have high repuration in India. The only technology for thermophilic biomethanation of spent wash available in India is the technology of Aqua Technos Asia Co. Ltd OBJECTS OF THE INVENTION The main object of the present invention is to provide an improvised process for the treatment of spent wash from distillery by thermophilic digestion. Another object of the invention is to provide improvised higher BOD, COD TDS and TSS reduction of the spent wash firom distilleries and yet another object is to get higher biogas generation and reduce the operating cost of the plant. Still another object is to convert existing mesophilic digesters into thermophilic digesters for treatment of spent wash in distilleries. SUMMARY OF THE INVENTION To meet the above objects, the present invention provides an improvised process for reduction of COD, BOD TDS and TSS simultaneously at thermophilic temperature range from theh spent wash from distilleries. The reduced operation cost is achieved by reduced power requirement, higher biogas production, reduced plant construction cost. In the improvised process there is no use of chemicals, no dilution of spent wash and no artificial pH adjustment is required to be carried out. The novelty of the process lies in well designed pattern flow, recycling of biogas into digester, multistage biodegradation. There is use of improvised sludge suction is ensure safe operation and longer life of the digester. By converting the existing digesters operating on mesophilic temperature range into thermophilic range using this invention. Capacity enhancement upto 40% can be well achieved. DETAILED DESCRIPTION OF THE INVENTION Biomethanation process (anerobic digestion) is, in other words, named as Bio-gas production plant due to the fact that input spent wash having organic pollutant is biodegraded and simultaneously biodegraded orgaic substances are converted to methane rich biogas in their gasification stage, which is utilized as boiler fuel for steam generation or fuel for power generation plants. This thermophilic biomethanation process treatment plant is designed for anerobic (primary) treatment of spent wash to achieved reduction upto 90% BOD, 70% COD and biogas generation upto 1.2 Ncum from biodegraded Kg of BOD in shortest residence time. As a pretreatment, a receiving pond and plate type heat exchanger is used for solid seperation and cooling down the wash to the desired temperature range. Spent wash at 50 to 55 c degree (thermophilic temperature) is fed into digester. Thereafter highly polluted organic compound is biodegraded in shortest residence time by thermophilic biomethanation system. DYNAMIC HORIZONTAL FLOW : In our earlier process and plants, horizontal flow of liquid takes plance through partition walls openings in the digester. It is now invented that by making the digester a multi compartment vessel by providing additional stream controllers, more linear velocity of the liquid can be attained thereby ensuring proper mixing and keeping biomass in suspended form for the higher biodegradation and biogas production. The linear velocity of the liquid is increased by providing stream container (with bottom openings) between two partition walls. The flow of liquid is dynamic horizontal flow to ensure better biodegradation. It is also invented that the number of partition walls and stream controllers to be provided would depend on the organic loading as well as the feed. STEP FEEDING SYSTEM : The spent wash feeding system is invented to comply with dynamic horizontal flow achieved by the introduction of newly designed stream controller. Feeding branch pipe length and location is newly desined to meet the requirement of multistage biodegradation. By incorporating this new design in our process and plant, instant and more homogeneous contact of spent wash with biomass is achieved thereby resulting in faster and better biodegradation. This is termed as step feeding system. COMPLETE LIQUID MIXING SYSTEM : The gaseration system has been provided in the earlier digesters to ensure agitation for mixing and to keep biomass in suspended form. A part of biogas is recycled by the gaseration system. It is now established that the design of gaseration lines and blower capacity depends on the height of the digester and the size of the digester. Further, it is now invented that the cylindrical shape of the inner clarifier obtains better efficiency than earlier provided conical shape. It is invented that more agitation is achieved by better gaseration by providing separate outer and inner gaseration lines, these lines are to be provided with diffusers on the bottom only. The new invented complete liquid mixing system comprises of Blowers, Gas scrubber. Moisture trap, and outer and inner gaseration pipelines with bottom diffusers. It is invented that for optimum biodegradation with new complete liquid mixing system, the gaseration ratio shall be between 3 to 5 cum/cum/day. The blower selection for recycling gas shall depend on this ratio. DESLUDGE SYSTEM : The problem of accumulated sludge was experienced in earlier digesters. It is invented that by providing specially designed desludge loops in each compartment of the digester. The location of these desludge loops are near the end of the compartments. As an improvement to ensure longer life of the digester, sludge- monitoring holes are provided on rooftop to watch the accumulated sludge level in the digester. MULTISTAGE BIODEGRADATION : It is invented that by incorporating stream controller, multistage biodegradation takes place with maximum biodegradation taking place in first compartment hence the maximum feed can be carried out in this compartment by means of step feeding system. GAS PRESSURE RELEASER : It is invented that a water seal type gas pressure releaser installed on rooftop near the gas dome will facilitate instant release of extra high pressure inside digester ensuring safe operation. CONVERSION OF MESOPHILIC PROCESS DIGESTERS TO THERMOPHILIC PROCESS : The mesophilic digesters require dilution of spent wash with water and for the same treatment capacity, the volume of mesophilic digester would be much more than that of thermophilic digester. With high biodegradation achieved due to our invention, we can convert mesophilic digester into higher treatment capacity thermophioic digester by incorporating our improvised process involving Dynamic horizontal flow, step feed system, desludge loops, compete liquid mixing system, equal level balancing pipelines involving muhistage biodegradation. CHEMICAL DOSING : In earlier plants chemical dosing are required to be done to maintain the pH, with our improvised process leading to high degree of biodegradation, no chemical dosing is required. RECOVERY AFTER SHUTDOWN : To overcome the difficulties faced for the quick reactivation after shut down in our earlier plants/digester; the present invention involves the provision of draining system to drain off the no bio mass liquid. ADVANTAGES OF THE INVENTION The present invention involves the treatment of spent wash fi-om distillery by thermophilic digestion and simultaneously producing valuable biogas. This present invention involves reduction of Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), Total Dissolved Solids (TDS) and Total Suspended Solids (TSS) from the spent wast alongwith high biogas production due to higher biodegradation by the thermophilic digestion. The process does not involve use of any chemical, thus its cost effective. The process does not involve use of any moving mechanism inside digester; thus it is very easy to maintain. STATEMENT OF INVENTION The present invention accordingly discloses a Biomethanation Plant comprising of desuldge means as herein described, desuldge loops provided at the bottom in each compartment, said means having holes on rooftop for monitoring level of sludge, means are provided for improving gaseration efficiency, a digester having multi compartment for multistage biodegradation with additional stream controllers between partition walls, said stream controllers having opening at the bottom, a spent wash feed means provided with valves on branch pipe lines on rooftop with cleaning mechanism, a complete liquid mixing means provided, a gas pressure releaser installed on roof top with cleaning mechanism, a complete liquid mixing means provided, a gas pressure releaser installed on rooftop near gas dome for releasing high pressure inside digester. As an another embodiement of the invention the invention discloses A process for treatment of Spent wash using the Biomenthanation plant as claimed in claim 1 comprising the following steps : (i) Sugarcane is fed into the sugar mill (ii) Sugar is extracted by known means (iii) Molasses are taken out and fed into the distillery Plant (iv) Alcohol is taken out by known means (v) Spent wash, which is highly toxic, is sent to Biomenthanation Plant by step feeding system where f treatment is carried out by multi stage Biodegradation as herein described, (vi) Secondary treatment by known means and discharging non-polluted effluents. I, Claim : LA Biomethanation Plant comprising of desuldge means as herein described, desuldge loops provided at the bottom in each compartment, said means having holes on rooftop for monitoring level of sludge, means are provided for improving gaseration efficiency, a digester having multi compartment for multistage biodegradation with additional stream controllers between partition walls, said stream controllers having opening at the bottom, a spent wash feed means provided with valves on branch pipe lines on roof top with cleaning mechanism, a complete liquid mixing means provided, a gas pressure releaser installed on roof top with cleaning mechanism, a complete liquid mixing means provided, a gas pressure releaser installed on rooftop near gas dome for releasing high pressure inside digester. 2. A Biomethanation Plant as claimed in claim 1 wherein the length of branch pipe is atleast 1 to 1.5 Meters from the bottom of the reactor. 3. A Biomethanation Plant as claimed in claim 1 wherein said gaseration means having blowers, gas scrubbers, moisture trap & inner gaseration pipe lines with bottom diffuser to achieve gaseration ratio between 3 to 5 cum/cum/day. 4. A process for treatment of Spent wash using the Biomenthanation plant as claimed in claim 1 comprising the following steps : (i) Sugarcane is fed into the sugar mill (ii) Sugar is extracted by known means (iii) Molasses are taken out and fed into the distillery Plant (iv) Alcohol is taken out by known means (v) Spent wash, which is highly toxic, is sent to Biomenthanation Plant by step feeding system where 1st treatment is carried out by multi stage Biodegradation as herein described, (vi) Secondary treatment by known means and discharging non-polluted effluents. 5. A process for treatment of Spent wash using the Biomenthanation plant substantially as herein described. 6. A Biomenthanation Plant substantially as herein described and illustrated in accompanying drawings.

Documents:

2580-del-2004-abstract.pdf

2580-del-2004-claims.pdf

2580-del-2004-correspondence-others.pdf

2580-del-2004-correspondence-po.pdf

2580-del-2004-description (complete).pdf

2580-del-2004-drawings.pdf

2580-del-2004-form-1.pdf

2580-del-2004-form-19.pdf

2580-del-2004-form-2.pdf

2580-del-2004-form-3.pdf

2580-del-2004-form-5.pdf

2580-del-2004-gpa.pdf