The Evolution of the HBS (Home Biogas System)

Brgy. San Roque, La Paz, Tarlac, Philippines

June 2003 – October 2007

The digester & biogas flame that spawned more research towards developing a
compact & low cost digester. Expecting that a small amount of biogas would be
produced, at the beginning, only a 2 liter Coke bottle was used to collect it.

Biogas proved to be very abundant & easy to produce. Instead of 2 liter bottles,
25 liter bottles were used in later tests of different designs & they were filling up
by as much as 6 liters/hr under a warm sun. At night, the biogas was used to
fuel a lamp.

As TPDs (Tubular Polyetheylene Digesters) seemed too weak & flimsy, digesters
made tarpaulin were made & tried. Biogas was collected in a storage bag
(bladder) also made of tarpaulin & used for cooking. Note how the test flame
is invisible & clean burning.

Success with the tarpaulin digesters prompted the construction of larger
digesters made of HDPE (High Density PolyEthylene) liners which were stronger
& more durable.

As HDPE is expensive & requires special equipment to fabricate, a digester
using HDPE liner only as a cover was developed. The idea became known as
the HBS or Home Biogas System.

Examples of HBS units built: One in Iligan, Philippines and another by
volunteers of BGET (Border Green Energy Team) using a UNDP grant for the
Padae School in Padae, Tak Province, Thailand.

A manure pond for a 400 sow (farrow to finish) farm was covered with HDPE
& modified to operate like a huge HBS. However, unavailability of funds for a
biogas-fueled genset keeps the biogas from being used to produce electricity.

The quest for a low-cost HBS that can be built anywhere (without special
materials like HDPE) has now resulted to the HBS2. A digester with an
all-concrete construction that can be built easily as a DIY (Do It Yourself)
by any farmer. As with the original HBS, free plans & instructions are available.
Email a request to: biofuelswork@gmail.com

Digester on the left is an undersized HBS2 (at 4.41 m3) while on the right is
an oversized HBS (22 m3.) The plans & instructions of the HBS2 are for a
5 m3 digester. It can be used in 10–40 hd pigfarms or where at least
10 liters/day of assorted animal manure can be found.

The HBS2 can be built for under 15,000 Philippine pesos or (U$300). Before
building, inquire about on-line tutorial lessons on the science behind biogas
production (or anaerobic digestion) & digester operation (design & operating
principles). See video presentations of an actual construction, informative
animations, problems to be avoided & innovative solutions.

For other questions or information, please email: biofuelswork@gmail.com
or visit our Home Page at: www.biofuelswork.com