Biomethanation in india

Biomethanation in india, biomass gasification in India, bio gas, trends, costs of biomethanation and biomass gassifiers, types, business challenges, opportunities 

Biomethanation involves the biodegradation of organic wastes under strict anaerobic conditions to yield methane-rich biogas.

Biomethanation of aqueous wastes involves hydrolysis, acidogenesis, acetogenesis and methanogenesis reactions, which generates a mixture of methane, carbon dioxide and other gases.

Biomethanation can be carried out in a single step or two steps.

In the process of hydrolysis, anaerobic bacteria breakdown complex organic molecules such as protein, cellulose, lignin and lipids into soluble monomer molecules such as amino acids, glucose, fatty acids and glycerol. Hydrolysis phase is relatively slow.

Acidogenic bacteria convert sugar, amino acids and fatty acids to organic acids, alcohols and ketones, acetate, Co₂ and H_2. The products formed vary with type of bacteria as well as with the temperature, PH etc.

Acetogenic bacteria convert fatty acids and alcohols into acetate, hydrogen and carbon dioxide. Acetogenic bacteria require low hydrogen for fatty acids conversion.

Methanogenesis is the formation of methane by microbes known as methanogens. Methanogenesis in microbes is a form of anaerobic respiration. Methanogens do not use oxygen to respire; in fact, oxygen inhibits the growth of methanogens. The terminal electron acceptor in methanogenesis is carbon. 

The two best described pathways involve the use of carbon dioxide and acetic acid as terminal electron acceptors:

CO₂ + 4 H₂ → CH₄ + 2H₂O

CH₃COOH → CH₄ + CO₂

The process of small-scale Biomethanation includes feedstock colleting, pretreatment, fermentation, treatment and purifying, storage and transportation.

Batch fermentation and semi-continuous fermentation are usual technologies for small-scale biomethanation. In batch fermentation technology, all the feedstock is added at the first. The biomethane generates fast at the beginning and then decreases. In semi-continuous fermentation technology, ¼ - ½ feedstock was added at the first. When the biomethane generation slows down, more feedstock is added to make the biomethane generation work in order.

Large – scale anaerobic digestion systems:

Pre-treatment process:

The biomass waste is conditioned in a pre-treatment process such as removal of foreign matters not suitable for anaerobic digestion, pulverization, dilution by water, thickening, and/or acid/alkali treatment. Some biomass wastes such as garbage, which is a mixture of various organic and inorganic matters, and, thus, is not always consistent in its composition and properties, are subjected to mechanical and/or magnetic separation in order to get rid of indigestible materials such as metals and plastics. The separated biomass waste is pulverized and added with dilution water to prepare waste slurry for the next unit process.

Slurry storage tank:

Prepared slurry is temporarily stored in a slurry storage tank for leveling diary fluctuations in both quality and quantity. If the ambient temperature is suitable, microbial activities of acidogens in the storage tank may increase. If this occurs, accumulation of organic acids in the slurry can cause a decrease in pH to as low as around 4. The slurry storage tank must be designed to resist corrosion due to such low pH conditions.

Methane fermenter:

Three major functional microbial groups are active in the methane fermenter. These three functions that take place sequentially are; hydrolysis, acidogenesis and methanogenesis. The final products of the reactions are methane and carbon dioxide. The hydrolysis reaction is often the rate-limiting pathway of an anaerobic digestion process on not-readily biodegradable or recalcitrant biomass such as sewage sludge and ligneous biomass, whereas the methanogenesis is likely to be the rate-limiting pathway on readily biodegradable biomass such as garbage and starchy waste water. In order to establish an efficient anaerobic digestion system, it is important to consider the rate-limiting pathway and to select the most suitable reactor design for the properties of anticipated biomass waste.

Fermentation waste water treatment:

Fermentation waste water discharged from the anaerobic digester usually contains high concentrations of organic matters, nitrogen compounds and phosphorous compounds. The fermentation waste water should be treated to reduce the concentration of these pollutants to meet the standards for final discharge to a receiving body of water or sewer system. The most typical fermentation waste water treatment system is the activated sludge process with tertiary treatment.

Biogas utilization:

Since most of the biomass waste contain proteins and sulfate salts, the biogas contain certain concentrations of hydrogen sulfide and ammonia, The biogas produced from sewage sludge, which sometimes contains a considerable amount of silicones, may contain siloxanes as well. Since these impurities can possibly cause damage to biogas utilization facilities such as a gas engine, gas boiler, gas turbine and fuel cell, and/or cause secondary air pollution, a biogas utilization unit process is often equipped with a desulfurization device and/or siloxane remover prior to the gas holding tank.

Advantages of Biomethanation:

• Production of thermal and electrical energy from waste or fermentable sub-products\
• Reduction in greenhouse gas emissions: Co₂ and CH₄
• Economic solution for the treatment of organic waste
• Agricultural diversification and recycling

An example of the economic viability of Bio-methanation plants

Project Case: 2 MW Biogas to Power plant

Total Investment: Rs.260 Million (Rs.130 Million/MW)

Capital subsidy (CFA): Rs.15 Million/MW (for mixed waste)

Plant Load Factor: 80% - 82%

Present power tariff band: Rs. 4.24 – 4.7/kWhr

Approx feedstock Reqmt: 11 Mt/MWhr @ 45% DS Content

Average Min Feedstock price: Rs.600/MT (landed at Site)

Price for Organic Compost: Rs.600/MT (current market prices)

Carbon Credits Revenues: 10000 – 20000 Credits/Annum

Overview of financial viability with CER Revenue:

Financial Indicators	Unit	Tariff at Rs.4.5/kWhr	Tariff at Rs.5.75/kWhr
Equity	%	30%	30%
Debt	%	70%	70%
Cost of Debt (min)	%	11%	11%
Equity IRR (pre tax)	%	9.0%	19.5%
Project IRR	%	10.7%	18.0%
Payback time	Years	9.2	5.45

Other Assumptions:

CFA: Rs.15 Million / MW

Sale price of Compost: Rs.1200/MT

CER Revenue: € 10 /CER

Overview of financial viability with CER Revenue:

Financial Indicators	Unit	Tariff at Rs.4.5/kWhr	Tariff at Rs.5.75/kWhr
Equity	%	30%	30%
Debt	%	70%	70%
Cost of Debt (min)	%	11%	11%
Equity IRR (pre tax)	%	3.5%	14.2%
Project IRR	%	5.7%	14.3%
Payback time	Years	12.3	6.8

Other Assumptions:

CFA: Rs.15 Million / MW

Sale price of Compost: Rs.1200/MT

CER Revenue: € 10 /CER

Biomethanation plants in India:

Biomethanation for Treatment of Slaughterhouse Waste at Medak, Andhra Pradesh (2 units of plants):

The first phase biomethanation plant for treatment of abattoir waste has been completed at M/s Al kabeer Exports Ltd., Medak, Andhra Pradesh, having an installed capacity of slaughtering and processing 500 - 600 buffaloes and 1500 - 2000 sheep / day.  The methane digester is based on UASB (Up-flow Anaerobic Sludge Blanket) technology and results in COD reduction of 75 to 80% and BOD reduction of 85 to 90%, besides producing about 3500 to 4500 cum/day of biogas having a methane content of about 65%. Adoption of the biomethanation technology has resulted in a saving of Rs.30 lakhs per annum on account of expenditure on chemicals besides an additional annual saving of Rs.30 lakhs on account of saving of furnace oil.  The successful adoption of this innovative technology has encouraged M/s Al-kabeer to set up one more biogas plant for the treatment of solid wastes, which is based on a state-of-the-art technology obtained from Austria. These biomethanation installations have shown the way to solve the problem of waste treatment and disposal in environmentally benign manner, which also appears to be financially profitable.   

Biomethanation Plant for Mixed Wastes at Vijayawada:

A demonstration plant based on biomethanation of 20 tonnes per day mixed wastes (i.e. 16 tonnes of vegetable market waste and 4 tonnes of slaughterhouse waste and sewage from the sewage treatment plant for dilution) for generation of power to Vijayawada Municipal Corporation (VMC), Vijayawada has been commissioned in February 2004. The generation of biogas is about 1600 cum; besides 5 tonnes of organic manure per day.  The biogas so produced is being used in a 145 kW imported biogas engine for generation of electricity.   The electricity generated is fed into the state electricity grid. 

Power generation through Biomethanation of Animal Waste at Ludhiana: 

Haebowal Dairy Complex in Ludhiana, spread over an area of 50 acres, has 1490 dairies with an animal population of 1,50,000 and generate about 2475 tonnes of animal droppings. The project utilize about 235 tonnes of waste per day to generate about 0.965 MW electrical energy.  The surplus energy after meeting the in house power requirement is fed to the state grid.  Besides, the electrical energy, the project also produced stabilized organic manure (about 7 tonne of 70% solids and 40 tonnes of 50% solids) per day. The plant was commissioned in June 2004, and since then it is working satisfactorily.

Biomethanation Plant for Vegetable Market Wastes at Chennai: 

A demonstration biomethanation plant for treatment of 30 tonnes per day Vegetable Market Wastes for Generation of Power at Koyembedu Market Complex (KMC), Chennai was approved in March 2003. The expected generation of biogas is about 2500 cum., besides 9-10 tonnes of organic manure having moisture content of 25-30% per day. The biogas produced is to be utilized in a 230 kW imported gas engine having in built co-generation unit for generation of electricity and thermal energy. The total cost of the sub-project is Rs. 352 lakh plus USD 320000 with NBB/ MNRE share of Rs. 264 lakh and USD 2,40,000.  The plant is currently under commissioning.

Biomethanation technology providers/suppliers in India:

ION EXHANGE WATERLEAU LTD.

ION HOUSE,PLOT NO 2,

SECTOR 18,

VASHI

NAVI MUMBAI 400705

TEL :0091-22-39132298

        0091-22-39890909

Website :www.ionexchangewaterleau.com

              www. ionindia.com

Contact : Ajay Popat -CEO

EMAIL   :ajay.popat@ionexchange.co.in

              popatajay@rediffmail.com

M/s ENKEM Engineers Pvt. Ltd                

824, Poonamalle High Road,

Kilpauk (Near KMC),

Chennai - 600010

Tel: 044-26411362/26428992

Fax: 044-26411788

 Email: enkem2000@vsnl.net

M/s Mailhem Engineers Pvt. Ltd.,

14, Vishrambag Society,

Senapati Bapat Road,

Pune - 411 016.

Tel: 020-24002285

Fax: 020-25659857

Email: info@mailhem.com

M/s REVA Enviro Systems Pvt. Ltd.,

3, Suyog Nagar, Ring Road

Nagpur - 440 015

Tel.: 0712-2743123, 2743124

 Fax: 0712-2743120

M/s Linde Process Technologies India Ltd.

38, Nutan Bharat Society, Alkapuri

Vadodara - 390 007

Tel: 0265-2336319, 2336196

Fax: 0265-2335213/2313629

M/s Hydroair Tectonoics Pvt. Ltd.,

401, “Devavrata”, Sector-17,

Vashi, Navi Mumbai-400 705

Tel.: 022-27892813/68/95

Fax: 022-27893892

M/s Chemtrols Engineering Ltd.,

Amar Hill, Saki Vihar Road,

Powai, Mumbai-400 072;

Tel: 022 –28575089/ 28570557

Fax: 022-28571913

Email: jaypee@chemtrols.org

M/s Degrimont India Ltd.

Water and the Environment

D-43, South Extension - II

New Delhi - 110 049

Tel.: 011-26481191, 26481192

Fax: 011-26228782

M/s Global Environmental Engg. Ltd.

1233/C, K. G. Mansion

Opp. Hotel Kohinoor Executive

Apte. Road, Pune - 411 004

Tel.: 0212-2327876, 2328007

Fax: 0212-2328441

M/s UEM India Limited,

D-19, Kalkaji,

New Delhi-110 019

Tel.: 011-26447825/ 26421634

Fax: 011-26239801

Email: uemindia@uemgroup.com

Ion Exchange Waterleau

Ion House, Plot No.2, Sector 18 Vashi,

Navi Mumbai 400 705, India 

Phone: +91-22-3989 0909

Fax: +91-22-2788 8156/2788 9839

E-mail: iewl@ionexchange.co.in

Source: http://www.eai.in/club/users/Shweta/blogs/8094