Renewable energy


Sunday, February 13, 2005

Biogas and codigestion

To produce 1 m3 of BIOGAS, to cook 3 meals daily for a small family of 4 to 6, you need at least 5 litres of pig manure/day. 8 sows will produce 5+ litres/day easily and your 36 heads total will probably give you at least 15 litres. A 2 m3 digester wil produce 1 m3 of BIOGAS/day -- good for experimental purposes. I suggest your first digester be at least 5 m3. This will produce more BIOGAS when needed and accommodate your farm's growth.

The China Fixed Dome, India Floating Cover and DOST-PSTC designs are the most popular here in the Philippines. Download drawings from the internet but I suggest you get professional help as the building process is not easy.

Here are people who can help:

Roberto Bajenting Trained at Asia-Pacific Biogas Research and Training Center, Chengdu City, Sichuan, China.
Provincial Agrarian Reform Officer, Cebu CityCell No: +63920-923-6930

Engr Orlando Anselmo. Has installed 35+ DOST-PSTC digesters in Aurora Province
DOST Officer, Baler, Aurora ProvinceCell No: +63915-569-9631

The BioDigester I designed is made of 1.5 mm HDPE or High Density Polyethylene. It’s the same material used for landfills worldwide. Working with HDPE requires special equipment and trained technicians. Building just one or two is not cheap and economical.

I have 5 m3 BioDigesters available as ready-to-install kits because I had them pre-fabricated and mass-produced, resulting in lower costs. You can have a complete 5 m3 BioDigester system for about P20,000.00 (a 10 m3 unit for about P30,000.00) plus P5,000 max for delivery and installation. To compute SAVINGS just remember: 1 m3 BIOGAS/day replaces one 11 kg tank of LPG worth P400.00 per month. Using 2 m3 BIOGAS/day will save P800.00 per month.

The CFD, IFC and DOST-PSTC digesters all cost over P25,000.00. For this reason, I have asked Bobby Bajenting and Engr Anselmo to help me promote the BioDigester. I avoided bagasse despite its energy potential for two reasons. It is not readily available and its near-solid nature will probably fill-up and clog my digester. As you said, there are lots of other wastes available. I have used grass cuttings from the local golf course, spoiled vegetables from the "palengke" and all our kitchen scraps.I am currently installing a 10 m3 BioDigester at my brother’s restaurant. I am also talking with local officials about a 10 m3 BioDigester for the "palengke" to digest vegetable scraps and provide some kitchenettes with cheap cooking gas.

When I started my BIOGAS experiments, I checked temperatures and pH. First with an expensive kit from BioResearch and eventually with plain litmus papers. I measured quantities of manure used, volumes of BIOGAS produced, etc. It was a lot fun – but largely unnecessary -- I think. Conditions for digestion in the Philippines are ideal. Its so EASY to produce BIOGAS here! Just follow some tried and tested procedures.


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