Solid Waste and Soil Science Flashcards
Americans dump how many pounds of refuse into landfills every year?
12-15 billion pounds
The average American produces __ lbs of refuse a day
6 lbs
Domestic solid waste is made up of organic and inorganic materials. What are the terms used for these categories and how are they different?
Organics - garbage - material decomposes
Inorganics - Rubbish - Material does not break down by decomposition
In the solid waste field, garbage and rubbish combined is referred to as _________________
Refuse
One of the biggest problems with refuse is ___________ because while it is organic it does not break down easily due to cellulose
Paper
Decomposition in landfills is primarily a (aerobic or anaerobic) process
anaerobic process primarily
Carbohydrates in the landfill are broken down into ________ and ___________ and odor is typically (present or absent
alcohol and organic acids
odors are absent
_________ containing compounds produce strong odors when decomposing
nitrogen
The key to a successful landfill is to control the _______________ because when they decompose their products can support insect, rodent, and bird populations
organic wastes
What are the three methods in which refuse can be buried or placed on the surface
Trench method
Area method
Valley or Ravine method
What is the trench method
aka: cut and fill method
Typically used on level terrain. Trenches are dug, solid waste fills trenches and dirt is placed on top. The trench is then compacted.
What is the area method
Refuse is dumped on the side of a slope and then covered with dirt. Continues into the slope is leveled.
Most common in the united states.
What is the valley or ravine method?
Refuse is dumped in the depression of a valley or ravine. Fill dirt is added and the area is compacted and built up.
Often used in large cities.
Can later be built upon as a golf course or park. No buildings due to settling 10-30%
What are Class I - 3 landfill types
class 1 - hazmat accepted class 2 - low level hazmat accepted class 3 - no hazmat accepted
What is the soil of choice for landfills and why?
Sandy loam - a mixture of compactible soil and sand which allows for good compacting characteristics but also good seepage for filtration.
What are 4 factors to consider when evaluating a potential site for a landfill?
- factors of ground water contamination
- location and accessibility. type of terrain (level of sloped)
- soil availability for cover and compaction.
- average direction of prevailing winds (must not affect nearby communities)
What is a daily cover?
6’’ of material, typically earthen material such as soil which is compacted to help prevent fly larvae and other reactions between the waste and the air.
Laid over the deposited waste everyday.
What is an alternative daily cover? ADC
A material other than earthen material used as a daily cover.
Typically waste derived materials such as mixed paper sludge or tire derived aggregate.
What is the final cover?
24’’ - a multilayered system of various materials which are primarily used to reduce the amount of storm water that will enter a landfill after closing.
Proper final cover systems will also minimize the surface water on the liner system, resist erosion due to wind or runoff, control the migrations of landfill gases, and improve aesthetics
Name 5 layers that are part of the final cover layer
top soil layer composed of nutrient rich soil
protective layer to reduce the effects of freeze/thaw
drainage layer which moves storm water
barrier layer
grading layer.
What is the ideal slope/percent/degrees for a landfill?
1:2, 50%, 26degrees (33’ 54’’)
What is the ideal slope/percent/degrees for the final closing of a landfill?
1:3, 33%, 18degrees (26’ 06’’)
The first 4 to 60 days a landfill is in (aerobic or anaerobic) state?
aerobic state
After 60 days a landfill is in what state?
anaerobic state
How often do landfills get inspected?
Once a month typically
What is containerization
An old technique no longer used where toxic chemicals were buried over absorptive materials (paper, rags etc.)
Define leachate
Any liquid waste that comes out of a landfill.
What are the various sources of leachate?
Rain water seepage
Liquid intentionally dumped at the landfill
What is the paint filter test?
Tests liquids for their viscosity and will dictate if the liquid waste can be accepted by the landfill for disposal
Define composting
Natural process of plant nutrient recycling. Plant materials such as grass and leaves are broken down by bacterial decay (saprophytic bacteria) in the compost resulting in nutrients being deposited back into the soil for use by other plants.
Name what happens in the 3 cycles of the decaying process in composting
first stage - bacteria degrade compost
second stage - fungus, mold, protozoans further break down plant life
third stage - insects such as millipedes, beetles and earthworms complete the cycle.
What can the end product of composting be used for?
It can be mixed with soil to yield more fertile soil for growing plants
Currently, 40-50% of waste to the landfills is ___________
yard waste
In the beginning of composting the heaps have temperatures between _____ and ______ which benefit the process how?
Between 140F and 160F
Help keep fly breeding to a minimum by killing off fly larvae
Is it advised to add foods grains and animal waste to a compost? why or why not?
No. Stick to yard waste only, green plants such as grass and leaves. Foods and grains hinder bacterial action, attract rodents, flies, and cause bad odors.