Solid Waste Exam 1 Lecture 4 Flashcards
What are Sanitary Landfill issues?
Landfill gas, Leachate, ground settling,
Noise, vector, odor , nuisance
Aesthetics
Constituents of Oxygen Demand
Total COD (Chemical oxygen demand, typically always larger than BOD, how much organic material can be oxidized through a chemical reaction)
Biodegradable COD (Biochemical Oxygen Demand (BOD), only the biodegradable fraction of COD)
Non biodegradable COD (what decomposers cannot process, not organic content that will be metabolized)
Constituents of Oxygen Demand
TKN (don’t know what this means)*
Organic Nitrogen
Ammonia
What kind of process is nitrification ?
It is an aerobic process because it requires oxygen
What is Carbon Fate?
It is when the landfill process is aerobic, then over time all of the oxygen content is used up and the process switches to anaerobic . Microbes use up all of the available oxygen and then the process become anaerobic (because a limited supply of oxygen) . Organisms are active in aerobic state for 4 to 60 days.
The effluent (what is remaining) is carbon that is left over
What is a benefit of the Carbon Fate anaerobic process?
Generation of bio gas : methane and a lot less sludge made.
Methane is used to produce electricity
When there is a high oxygen demand there is a . . .
High availability of carbon
What is sludge also known as?
Biomass
-Sludge helps microorganisms grow in aerobic state
What are the five complex interactions among different microorganisms
- Fermentative bacteria –turn it into fatty acids
- H2 producing acidogenic bacteria : generate acids
- H2 consuming acetogenic bacteria : generates acetates
- CO2 reducing methanogens –> CO2 and hydrogen to make methane
- Aceticlastic methanogens
Concerns of gas generation
Methane gas is explosive
Anaerobic decomposition
CO2 dissolve in water can acidified to to carbonic acid (corrosive)
Nitrate, traces of oxygen, VOCs
Health threats, destroys vegetation, and contaminates groundwater
Major concern of Leachate “garbage juice”
Formed as water migrates through solid waste, picking up a variety of biological and chemical contaminates
Greatest threat is contamination of groundwater
Usually collected and taken to a wastewater treatment plant for processing
Leachate Properties
Concentrated soluble organic materials
Increase concentration of inorganic
Depletes dissolved oxygen
Bacteria and viruses
Leachate basics
Follows the path of least resistance for migration
To control leachate : inspect, have a lining system, and control what goes into the trash (biodegradable)
For disposal and treatment : discharged to a lake, settling pond depending on what it is .
- discharged to a sewer
- land farming : soil amendment
- recycled back into land fill
Migration of gas and leachate
High soil permeability and low moisture content = moderate migration rate
Low soil perm and high moisture content = moderate migration
High soil perm and high moisture content = high migration rate
Low soil perm and low moisture content = low migration rate
Landfill siting and design process
Planning - identify need, site design strategy , asses alternatives, set criteria
Site selection - surrounding community, facility design to be approved by regulatory agencies and county , must be 6 statue mile between airports and new landfills
Facility design
Implementation / operation - daily log book or files, inspection records, gas monitoring results, records of weights / volumes/ excavations, no more than 1.25% methane within any portion of any on site structures and no more than 5% of methane gas migrating from the disposal site
