UNIT VIII ESSAY
of sand or gravel placed against the bottom liner of the landfill. The collected leachate is moved
to a holding tank or pond, where it waits to be treated on-site or hauled wastewater treatment
facility. Another feature is cells, which are the area within a landfill approved and constructed for
waste disposal. These cells vary in size from a few acres to over 20 acres. These cells are the
preparation area for waste coming into the landfill (Advanced Disposal Services, Inc. 2019).
Currently, many countries are facing the problem of remediating contaminated soils. One
soil remediation technology is In-Situ Chemical Reduction-Oxidation. This involves the
placement of a reducing agent or reducing material in the subsurface to degrade toxic organic
compounds to potentially nontoxic or less toxic compounds, immobilizing metals through
adsorption or precipitation, and degrading non-metallic oxyanions (Bai, Luo, Shi, Xie, Liu,
Zhou, Yan, & Li, 2015).
Another technology is In-Situ bioremediation of contaminated soil. This
involves using the aerobic process known as bio-venting to supply oxygen to the contaminated
soil anywhere above the water table.
Outside of oxygen, nitrogen, or other nutrients may also be
pushed from the air is used to increase the growth rate of the micro-organisms.
An electrostatic precipitator (ESP) uses an electrical discharge to charge particles so that
particles can be readily deposited onto grounded metal plates, thereby reducing particulate matter
from the environment. Advantages of ESP are its ease to clean, low operating costs, high
efficiency, able to handle large amount of gas flow rates with low pressure, its ability to remove
dry and wet particles of particulate matter and ozone air pollutants and has a flexible temperature
design (Day, Xiang, Mo, Clyde, Weschler, Li, Gong, Chung, Zang, & Zhang, 2018). Since the