PART 2: SOLID WASTE AND SOIL POLLUTION TREATMENT

Solid Waste

All the wastes arising from human and animal activities that are normally solid and are discarded as useless or unwanted

• Reduce

• Reuse

• Recycle

• Recover

• Residue

Hierarchy of Waste Minimization

Waste Reduction

Processes redesigned to reduce amount of waste generated

Waste Generation

Activities in which materials are identified as no longer being of value, and are either thrown away or gathered together for disposal

Reuse

Waste may be diverted to re-use

On-site Handling, Storage, and Processing

Of primary importance because of aesthetic, public health and safety, and economic considerations

Collection

Gathering and hauling of solid wastes to a designated location (ex. transfer station, processing station, or a landfill disposal site)

Disposal

Final functional element

On site handling

Activities associated with handling of solid wastes until they are placed in storage containers before collection

Hazardous Waste Operations and Emergency Response

What does HAZWOPER mean?

collection agency

Containers are usually owned by the ________________

industrial organization

Space for container location is usually owned by the commercial or _________________

• Recover usable materials

• Reduce volume

• Alter physical form

Elements of On-site processing:

Biological processes

What is the most common processing technique for Hazardous Waste?

Identification of Waste Constituents

the key item in any processing (and disposal) scheme

Identification of Waste Constituents

a responsibility of the waste generator

refuse derived fuel (RDF)

light combustible materials are often identified as ____________________

Composting and anaerobic digestion

, the two most highly developed biological processes

Composting

The entire process involving both separation and bacterial conversion of organic wastes

aerobically or anaerobically

Composting can either be accomplished ______________________

Compost / humus 

The end product remaining after dissimilatory and assimilatory bacterial activity

Anaerobic fermentation

Anaerobic Digestion is also known as _________________

Anaerobic Digestion

process used for the production of methane from solid wastes

Combustion

The process of burning something; an exothermic process

Gasification

Partial combustion of a carbonaceous or hydrocarbon fuel to generate a combustible fuel gas rich in carbon monoxide and hydrogen

Pyrolysis

decomposition brought about by high temperatures

Pyrolysis

destructive distillation

Dump

Most common disposal method

Dump

an accumulation of refuse and discarded materials; a disorderly, slovenly, or objectionable place

Geologic serenity

Sediment records from the cores indicate that the region has been tranquil for 65 million years, unperturbed by volcanic activity or by shifting of the earth's tectonic plate

1. Both are used for waste storage, but landfills are regulated by the government

2. Dumpsites are smaller

3. Landfills have leachate collection and treatment systems

4. Dumpsites have no liner to collect liquid waste 

5. Dumpsites may or may not be covered with soil, but landfills are always covered with soil

6. Dumpsites produce toxic gases

7. Landfill wastes cannot rot

Dumpsite vs Landfill (7)

Landfill

controlled disposal of solid wastes on or in the upper layer of the Earth’s mantle; a large scale operation

DEPRESSION [TRENCH] METHOD

for locations where natural or artificial depressions exist

AREA METHOD

when terrain is unsuitable for excavation of trenches in which to place solid wastes

carbon dioxide and methane

Principal gases produced from anaerobic decomposition:

Carbon dioxide and methane

These gases occupy over 90% of the gas volume

Methane

Most escapes to the atmosphere, but some accumulate below buildings or in other enclosed spaces

• 1.5 times as dense as air

• 2.8 times as dense as methane

Carbon Dioxide is ___ times as dense as air, ___ times as dense as methane

vents

Control of Gas Movement is done by installation of ____ made of materials that are more permeable than the surrounding soil

gravel

Gas vents are typically constructed of _____

Barrier vents

to control the lateral movement of gases

Wall vents

often used in conjunction with lateral surface vents buried below grade in a gravel trench

perforated pipes

Control of downward movement of gases can be accomplished by installing ______________ in the gravel layer at the bottom of the landfill

Gas wells

to vent the gas to the atmosphere if gases cannot be vented laterally

Passive venting system

The system using Gas wells to vent the gas to the atmosphere if gases cannot be vented laterally

Landfill sealants

materials that are more impermeable than soil to control movement of gases through soil formation

Compacted clay

Most common landfill sealants

Gas-recovery wells (active venting system)

Clay and other lines are used when landfill gas is to be recovered

Leachate-recirculation systems

a gas-recovery system where leachate is collected and recycled to the top of the landfill and re-injected through perforated lines located in drainage trenches

Gas recovery systems

Gas is used to run spark-ignition diesel engines to generate power for sale to the grid

bottom of landfills

Where are leachates found?

Darcy’s Law

Rate of seepage of leachate from the bottom of the landfill can be estimated by___________

Sludge

the residual, semi solid material left from industrial wastewater, or sewage treatment processes

Hydrolysis process

Conversion of insoluble high molecular compounds to lower molecular components

Acidogenesis process

Conversion of soluble lower molecular components to high molecular compounds

Methanogenesis process

Conversion of volatile acids & intermediate products to final product of methane and CO₂

Volatilization

This low-cost method causes mechanical drawing or air venting through the soil.

Biodegradation

This method is effective on some non-volatile compounds.

Phytoremediation

This method makes use of plants to decontaminate soils and water. It is effective with several inorganic and organic chemicals

Leaching

This method involves leaching the soil with water and a surfactant.

surfactant

The __________ lowers the surface tension of water, thus removing the contaminants.

Vitrification

In this method, contaminants are solidified with an electric current, resulting to contaminant immobilization.

Land treatment

In this method, the contaminated soil is excavated and spread over land for natural processes such as biodegradation to occur to decontaminate the soil.

Thermal treatment

In this method, the excavated soil is subjected to extreme heat using a thermal incinerator.

Asphalt incorporation

Contaminated soil in this method added to hot asphalt mixes which are then used for paving roads.

Solidification/Stabilization

The method involves the incorporation of an additive to the excavated, contaminated soil so that the contaminants are encapsulated.