CEN 304 Exam II Review (copy)

Porous Media

Particles of solids (sand, soil) with spaces (pores) in between.

Saturated Zone

The area where pores are filled with water.

Vadose Zone

The layer where pores have a mix of air and films of water.

Porosity

The percentage of empty space that exists within a particular porous media.

In situ methods for groundwater remediation

Techniques such as bioremediation and chemical reaction that treat groundwater directly in place.

Comprehensive Environmental Response, Compensation and Liability Act (CERCLA)

Established the National Priorities List (NPL) for sites needing hazardous waste cleanup.

Largest sector using water globally

Agricultural sector.

Maximum Contaminant Level Goals (MCLGs)

Non-enforceable standards set by the EPA.

TMDL for Belleville Pond

Developed to address phosphorus pollution.

BOD measurement duration

Measured over a 5-day period.

Theoretical Oxygen Demand

Determination method that requires knowing the structure and concentration of every molecule.

Chemical Oxygen Demand

Overstates impact on natural waters.

Biochemical Oxygen Demand (BOD)

Takes a long time to measure.

Final DO for proper BOD measurement

Must be at least 1 mg/L.

Oligotrophic

Nutrient-poor water bodies.

Eutrophic

Nutrient-rich water bodies.

Hypoxia

A severe oxygen deficiency.

Mesotrophic

Moderate amount of dissolved nutrients.

Water Treatment Steps

1. Pre-screen, 2. Coagulation, 3. Flocculation, 4. Sedimentation, 5. Filtration, 6. Final Disinfection.

Coagulation

Process of causing suspended particles to merge to form larger particles.

Flocculation

Aggregation of destabilized particles to form flocs.

Van der Waals Forces

Weak attractive forces that occur over long distances.

Disinfectants used to kill pathogens

UV light, chlorine, ozone.

Sedimentation particle collection

Particles with vs > vc will be collected.

Non-carbonated hardness

Cations associated with non-alkalinity anions (e.g., SO4-2).

Wastewater treatment steps

1. Pretreatment, 2. Primary treatment, 3. Secondary treatment, 4. Tertiary treatment, 5. Disinfection.

Yield Coefficient

Quantity of organisms produced per unit food utilized.

Mixed Liquor

Mix of activated sludge and wastewater.

Solids Retention Time

Average amount of time microorganisms are kept in the system.

Nitrification

The conversion of ammonia to nitrate.

Anoxic Zone

A region lacking oxygen.

Phosphate Accumulating Organisms

Microbes that uptake large amounts of phosphorus.

Low F/M ratio

Indicates that organisms are saturated with food, leading to poor treatment efficiency.

Nitrogen and phosphorus removal explanation

Nitrogen is removed biologically through nitrification and denitrification; phosphorus is removed chemically or biologically.

TMDL explanation

Total Maximum Daily Load is the maximum amount of a pollutant a water body can receive; states prepare TMDLs to define limits and reduce pollution.

In situ vs ex situ techniques

In situ methods treat contamination on-site; ex situ methods involve treating groundwater at the surface.