Municipal Solid Waste Management

In hauled container system, 'Haul' time includes. The time required to reach the disposal site, starting after the container whose contents are to be emptied has been loaded on the track, plus the time after leaving the disposal site until the truck arrives at the location where the empty container is to be redeposited.
Time spent at the disposal site is not included.

Assuming 1 \mathrm{Kg} of solid waste
\begin{array}{|c|c|c|c|c|} \hline \text {Component} & \text {Percent}& \text {Mas (Kg)} & \text { Energy} & \text { Energy}\\ & \text{by mass}& & \text{content} & \text{of waste (MJ)}\\ \hline Food \; waste & 20 & 0.2 & 4.5 & 0.2 \times 4.5=0.9 \\ \hline Paper & 45 & 0.45 & 16.0 & 0.45 \times 16=7.2 \\ \hline Carboard & 5 & 0.05 & 14.0 & 0.05 \times 14=0.7\\ \hline Plastics & 10 & 0.10 & 32.0 & 0.1 \times 32=32 \\ \hline Others & 20 & 0.20 & 80 & 0.2 \times 8=1.6 \\ \hline \end{array}
Energy produce from 1 \mathrm{Kg} work =13.6 \mathrm{~mJ}
Moisture content =26 \%
Solid content =100-26=74 \%
Therefore 1 \mathrm{Kg} of waste consist of =0.74 \mathrm{Kg} dry mass
\therefore \quad Energy content based on dry weight
\begin{aligned} & =\frac{13.6}{0.74}=18.378 \mathrm{~mJ} / \mathrm{Kg} \\ & \simeq 18.40 \mathrm{MJ} / \mathrm{Kg} \end{aligned}

(A) is false. The Higher Heating Value (HHV) of Refuse-Derived Fuel (RDF) processed from Municipal Solid Waste (MSW) is typically higher than the HHV of unprocessed MSW. This is because RDF processing removes non-combustible materials from MSW and concentrates the combustible fraction.

(B) is true. RDF can be produced in various forms including pellets, fluff, and powdered form. The form of RDF depends on the specific process and intended end use.

(C) is partially true. RDF processing typically removes a significant portion of the inorganic fraction of MSW, but not all of it. The remaining inorganic fraction is typically mixed with the RDF product.

(D) is false. RDF can be used as a fuel in a variety of combustion systems, including those that burn oil. In fact, RDF is often used as a supplemental fuel in cement kilns and other industrial processes that also use oil as a fuel.

Wt. of water initially present =frac{10}{100} \times 30=3mT
Wt. of solid =30-3=27mT
In ideal condition,
Wt. of solid =27mT
M/C=50%
Wt. of water =27mT
Amount of water needed to get ideal condition = 27 - 3 = 24 mT

C_{100}H_{250}O_{80}N+xO_2\rightarrow 100CO_2+\frac{247}{2}H_2O+NH_3
\begin{aligned} 80+x \times 2&=200+\frac{247}{2}\\ x&=121.75 \end{aligned}
1 mole of MSW required 121.75 mole of oxygen No. of moles of MSW
=\frac{1 \; ton}{(100 \times 12+250+80 \times 16+14)g}
No. of moles of O2 required =121.75 \times \frac{1 \; tonne}{2744g}
\begin{aligned} \text{wt. of }O_2&= \frac{121.75}{2744}\times 32 \; tonne\\ \text{Mass of air }&= \frac{1.42}{0.23}\times 10^3 Kg\\ &=6.174 \times 10^3kg\\ \text{Density of air }&= 1.3 Kg/m^3\\ \text{Volume of air }&= \frac{6.174}{1.3}\times 10^3 m^3\\ =4749.2 m^3 &\text{per tonne of MSW} \end{aligned}