*4.2.2. Composting for waste disposal*

Compost is most demandable nutrient source in the crop field. This approach allows growers to spend less money for their initial cultivation inputs. Also, higher yield will be observed by using compost instead of synthetic fertilizer [36]. Different types of composting methods are used on the basis of grower's choice and wastes types (**Figure 3**).

#### *4.2.3. Biofuels (bioethanol, biogas)*

Waste can be disposed through converting the wastes and by-products into biofuels. Bioethanol and biogas production nowadays appears as the most sustainable waste management program, which has some significant economic values.

Bioethanol can be processed through horticultural by-products such as carrot peels, banana peels, and other crops parts, which previously can be dried in the sun. The product can be ground and sieved for further processing. After that, the products can be pretreated with 1 N NaOH for 2 hours. Then draining or in other words alkali subsequent washing can be done. Enzymatic hydrolysis by cellulase enzyme leads to saccharification. Then the inoculation of *Saccharomyces cerevisiae* is required. Then the fermentation and distillation are done for bioethanol production (**Figure 4**).

The other way for wastes disposal as the biofuel source is biogas production. Nowadays we can see the rapid adaptation of this disposal system in our rural areas also.

In case of biofuel products, horticultural by-products can be utilized in effective way. Different content of organic matters can yield the sufficient amount of methane gas (**Table 8**).

**Figure 3.** *Different composting methods [37].*

#### **Figure 4.**

*Flow chart for bioethanol production by cellulase enzyme [38].*


#### **Table 8.**

*Biogas generation rate from the horticultural by-products [39].*

*Sustainable Horticultural Waste Management: Industrial and Environmental Perspective DOI: http://dx.doi.org/10.5772/intechopen.101689*
