1. Lecture (5): Waste treatment and disposal

2. Lecture (5): Waste treatment and disposal
Lecture (4): Lecture objectives:
By the end of this lecture students should be able to:
To know the methods of reducing waste.
To know the integrated waste management.
To know the roads conservation.

3. Lecture (5) Topic No (1): Waste treatment and disposal by healthy burial.
Common method of solid waste disposal.
Landfills are the oldest methods of waste disposal in the world.
The versatility and simplicity of it in terms of technical requirements, environmental and socio-economic aspects.

4. landfilling can be considered as the cheapest method to run.
landfilling is expensive or comparable to other methods due to government policy and availability of land.

5. Production Of Landfill Gas:
Landfill gas is produced during the natural breakdown of biodegradable waste.
The composition of landfill gas changes over time.
The gas from a typical landfill site consists mostly of methane and carbon dioxide.

6. LANDFILL FIRES
As waste decomposes it generates heat and underground fires may start.
These are difficult to extinguish, may last for long periods, and may spread throughout the landfill.

7. LANDFILL DESIGN
Modern landfills are designed to minimize these problems:
Location
Landfill Liner
Compaction of waste
Daily Cover
Landfill Cap
Leachate Management System
Landfill Gas management System

10. When landfill is full, layers of soil and clay seal in trash
Topsoil
Sand
Electricity generator building
Clay
Leachate treatment system
Garbage
Methane storage and compressor building
Probes to detect methane leaks
Pipes collect explosive methane for use as fuel to generate electricity
Methane gas recovery well
Leachate storage tank
Compacted solid waste
Figure 21.15
Solutions: state-of-the-art sanitary landfill, which is designed to eliminate or minimize environmental problems that plague older landfills. Since 1997, only modern sanitary landfills are allowed in the United States. As a result, many small, older local landfills have been closed and replaced with larger regional landfills. Question: How do you think sanitary landfills could develop leaks of toxic liquids?
Leachate pipes
Groundwater monitoring well
Leachate pumped up to storage tank for safe disposal
Garbage
Sand
Synthetic liner
Leachate monitoring well
Sand
Groundwater
Clay and plastic lining to prevent leaks; pipes collect leachate from bottom of landfill
Clay
Subsoil

11. Site considerations: Is located in a geologically stable area
Is not located on a major aquifer;
Is not located in a vulnerable area;
Is designed to reduce the risk of damage to the environment and human health;
Will be monitored regularly for the duration of operations and aftercare period

12. Air pollution from toxic gases and trucks
Sanitary Landfills
Disadvantages
Advantages
No open burning
Noise and traffic
Dust
Little odor
Air pollution from toxic gases and trucks
Low groundwater pollution if sited properly
Releases greenhouse gases (methane and CO2) unless they are collected
Can be built quickly
Low operating costs
Slow decomposition of wastes
Figure 21.16
Advantages and disadvantages of using sanitary landfills to dispose of solid waste (Concept 21-4). Question: Which single advantage and which single disadvantage do you think are the most important? Why?
Can handle large amounts of waste
Output approach that encourages waste production
Filled land can be used for other purposes
Eventually leaks and can contaminate groundwater
No shortage of landfill space in many areas
Fig , p. 576

13. Topic No (2): Waste treatment and disposal by biological analysis fertilization.
biological methods, composting and anaerobic fermentation are the most common process in using,
while due to the odour emission and low treatment capacity, composting is not so popular as anaerobic fermentation.

14. Is a natural bio-degradation process that takes organic wastes turns into nutrient rich food.
Allowing organic materials to sit in one place for months until microbes decompose it.
Is one of the best method of waste disposal.
Turn unsafe organic products into safe compost.
It is slow process and takes lot of space.

15. Topic No (3): Waste treatment and disposal by incineration.
Is a type disposal method in which municipal solid wastes are burned at high temperatures
Convert waste into residue and gaseous products.
Reduce the volume of solid waste to 20 to 30 percent of the original volume,
Decreases the space they take up and reduce the stress on landfills.
This process is also known as thermal treatment

16. Incineration, Advantages and Disadvantages

17. Solutions: A Waste-to-Energy Incinerator with Pollution Controls