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1 Anaerobic Co-digestion as a Smart Approach for Enhanced Biogas Production

play a pivotal role in this process of biodegradation, without it recycling would have

been unimaginably slower.

1.1.2

Anaerobic Digestion (AD)

Naturally existing anaerobic ecosystems such as paddy fields, swamps, lakes, ponds,

intestine of ruminants, and ocean sediments rich in dead organic matter have

paved way for microbes especially the archaeal obligate anaerobes-methanogens,

mutual togetherness with other prokaryotic anaerobe leading to the production

of methane. Though it can be attributed as a natural process, it leads to release of

methane, a potential greenhouse gas capable of global warming far many times

higher than carbon dioxide (CO2). Anaerobic digestion (AD) as a technology refers

to a provision of a closed condition for efficient digestion of the organic waste and

to collect the by-product, methane.

The benefits of AD are immense for both the economy and ecosystem:

●Firstly, the digestion takes place in a closed environment, thereby preventing air

pollution from obnoxious gases or disease-spreading germs.

●There is no issue of leachate escaping into water bodies and thus prevents open

water body pollution.

●No underground seepage and pollution of groundwater.

●Faster degradation of organic matter compared with composting (aerobic).

●The AD process can be easily monitored circumventing the problems, for example,

seasonal variation in temperatures.

●A microbial consortium can be developed, and it would aid in continuous and

efficient digestion of waste.

●Biogas production with a range of fuel applications.

●Downstream processing is not required as biogas collects in the head space and is

siphoned off for clarification and usage.

●Further effluent treatment would not be necessary as the slurry can be used as

organic manure.

●Pathogens are inactivated, thus rendering the digestate harmless and safe.

The drawbacks are few, but critical enough to be highlighted:

●Limited access to high-quality feedstock that is free of contamination

●Non-perennial aspects of feedstock

●Transportation costs

●Long-term sustainable biomethanation

●Unexpected digester failures

●Maintenance of high fuel quality

●Issues of multistakeholders (in case of co-digestion)

The first four issues are related to feedstocks and its management, while the last

three issues are related to lack of good microbial inoculum. Thus in this chapter,

these two aspects of feedstock and real-time monitoring of operational parameters

are dealt in detail.