Our huge dependency on the centralized waste treatment
structures along with the increasing demand in energy is driving the need for
decentralized, alternative structures at a small scale. How far can these
technologies and systems go to sustaining the households? Australia has the
answer for it.
The households are responsible for consuming almost
twenty-six percent of the energy in Australia and produce about thirty percent
of the total solid waste that’s generated. Energy, which is used in Victoria’s
households and throughout the world comes primarily from the centralized
thermal plants where 2/3rd electrical energy generated are lost in
the distribution.
As for waste water production in the households, the human
excreta is taken out with inconsistent amount of water and treated in costly,
centralized, large plants to be discharged into the water bodies later. Simultaneously,
the solid waste is even collected as well as transported to long distances to
the big landfilled and centralized plants.
Wastewater and waste often pose an environmental and health
hazard, especially where the right treatment infrastructure doesn’t exist. But
they are an important resource in an inappropriate place that may be used for
obtaining energy as well as valuable products by a wide range of well
established and emerging technologies like anaerobic digestion.
Because of the low population in the urban areas and
presence of the isolated regions and aboriginal communities without any
connection to sewer or grid, the potency for a small scale alternative
decentralized system is huge in Australia especially in Victoria.
The SSAD (Small Scale Anaerobic Digestion) is a promising
decentralized technology where various feedstocks are degraded in absence of O2
to generate digestate & biogas in Victoria (methane and CO2). Energy balance in such systems is helpful because
biogas may be used as a renewable energy source whereas digestate may be used
as an important fertilizer. Presently,
several small digesters are installed in many rural areas of India, China and
several other countries. The biogas is used for cooking with use of adapted
cooking stoves however several other applications like biogas mantle lamps,
generators and refrigerators are becoming very common.
One more emerging technology for the small scale
applications is MCHP or micro-combined heat and power device where the turbine,
fuel cell or engine is used for generating heat as well as electricity. While
big-scale CHP systems were used for several years, MCHP have just started to
become popular but have the potency for extensive usage. This new technology
usually generates between 5-20 kW. But because of the cost, they are often used
in the developing nations for replacing the conventional boilers.
The combination of the above mentioned two technologies can
contribute significantly to sustainable production of thermal and electrical
energy in Australian households.