Page 411 - Refining Biomass Residues for Sustainable Energy and Bioproducts

Agroindustry wastes: biofuels and biomaterials feedstocks for sustainable rural development 371

previous section, the type of wastes produced and its quantity depends on the type
of the agroindustry (Sadh et al., 2018a,b). Even, the characteristics of wastes from
same type of agroindustry may differ depending on the variations in processes as
well as the input substrates. Therefore it is reasonable that the extent of utilization
of such wastes from agroindustry must be based on the industry type and various
processes involved in generation of waste. In this section an emphasis has been
given on various processes available for utilization of agroindustry wastes.
The recovery, reuse, or recycling of agroindustry wastes for further utilization
are important for developing raw materials for other valuable products. Depending
on the type of waste and their characteristics, a systematic process for utilization is
adopted. Fig. 16.2 shows the step by step procedure for evaluating suitability of
agroindustry wastes for agricultural use (Pawełczyk and Szczygieł, 2009). As seen
from the figure, it is clear that the processing of agroindustry waste depends on the
composition of waste (i.e., nutrient and organic content). Usually, the path for trans-
forming waste into raw material or directly valuable product can be categorized
into physical, chemical, thermochemical, and biochemical processes. Physical pro-
cesses generally involve heat treatment, washing, blending, extraction, microwave
treatment, etc. Other than that, an intensive treatment of materials in grinders is
also utilized. Chemical processes generally make use of reagents for changing the
chemical composition of waste components. Common chemical reactions in such
processing include neutralization, reduction, oxidation, and decomposition. At last,
biochemical processes involves the use of microorganisms for processing agricul-
tural waste containing significant organic content (i.e., composting). Such method
is regularly improved for enhancing useful properties and reducing environmental
degradation and also cost. The processes involved for utilization of agricultural
should ensure rapid use of residues. In addition, before processing, the residues also
should be otherwise allowed to be stored under favorable conditions that do not
cause spoilage of it. In the following subsections, more specific description about
various processes involved in utilization of agricultural waste is described.

16.3.1 Solid-state fermentation
SSF has been mostly utilized in food processing, but recently, it has gained popular-
ity due to its use in the production of value-added products (Pandey, 2003). SSF of
agrowastes has been also used to produce biofertilizer. The most common method
adopted for conversion using SSF is mentioned in Attiya and Ashour (2002).
Agrowastes produced from pineapple, banana, papaya, and citrus orange can be
converted to biofertilizer using abovementioned method. Studies in literature have
indicated that the fertilizer produced from agrowaste such as residue from sugar-
cane juice can increase yield of rice and straw significantly (Kalaivanan and
Hattab, 2008). The process generally involves placing of agroindustry waste into
polyethylene bottle and then adding water into it. The bottle is kept at room temper-
ature till soluble product is formed. The filtered soluble product is the fermented
solution, which is also known as first batch of fertilizer. For second batch of fertil-
izer the filtered solution is used as inoculum precursor to the next SSF process. The