FE Environmental Part 3

Flashcards from the notes I've taken in preparation for the Environmental FE. This covers these topics: water/wastewater, fundamental principles

tertiary treatment

used in WWTP to remove nutrients/pollutants such as BOD and SS

nitrification

oxidation of ammonia to nitrate

its toxic to fish and causes algal blooms

why does ammonia need to be removed in WWTPs?

denitrification

reduction of nitrate to nitrogen gas

it causes eutrophication

why does phosphorus need to be removed in WWTPs?

eutrophication

excessive richness of nutrients in water bodies; causes dense plant growth and lack of oxygen

residential wastewater, industrial wastewater, infiltration/inflow, stormwater

4 influent flows in a WWTP

infiltration

groundwater enters through joints/leaks

inflow

surface water enters through manholes

combined sewer system

stormwater and rainfall in one pipe

dry, wet, peak

WWTPs must be designed for average ____ weather flow, average ____ weather flow, and ____ flow rate

suspended solids

SS

pretreatment

used in WWTPs to remove large objects, grit, and floating materials

primary treatment

used in WWTPs after pretreatment to remove BOD and SS

secondary treatment

used in WWTPs after primary treatment to remove BOD and SS; requires biological treatment

theoretical oxygen demand

ThOD

ThOD

oxygen demand calculated from a balanced chemical reaction

CBOD

chemical oxygen demand

microorganisms

consist of a single cell or cell cluster

eukaryotes

cells that contain a nucleus

prokaryotes

cells that do not contain a nucleus

filtration plant

surface water plant that includes coagulation and sand filtration

simple disinfection

groundwater plant that includes chlorination

softening plant

WTP that treats water with high hardness

coagulation

WTP method to alter colloids so that they’re able to flocculate and form larger particles

softening

WTP method of removing chemicals that make water hard

lime and soda ash

what chemicals are used in water softening?

flocculation

WTP method that mixes aggregates so turn into larger, settleable flocs

recarbonation

WTP method that lowers the pH of the system

filtration

WTP methos that removes residual turbidity; passes through sand

hardness

prevents soap from lathering; causes scum or white crust

acids

release protons (H+)

bases

associate with protons (OH-)

HNO3, HCl, H2SO4

strong acid examples

CaOH2, CO3

strong base examples

buffer

a solution that resists a charge in pH

alkalinity

measure of acid neutralizing capability

antidegradation policy

existing water bodies should be maintained and protected

clean water act

1. eliminate the discharge of pollutants into water

2. all WWTPs required to perform secondary treatment

3. NPDES system for every point source discharge of wastewater into the environment

safe drinking water act

1. required public notification

2. disinfection of all public water supplies

3. monitoring of contaminants

fixed film

microorganisms grow attached to a surface

lagoon

large shallow pond that uses natural biological activity to degrade nutrients out of water

phytoremediation

use of plants to remove and degrade contaminants

belt filter press, centrifuge, drying beds

sludge dewatering examples

composting

aerobic decomposition mixed with bulking agents

land application

application of treated sludge to land

irrigation, industrial, sprinklers, toilet flushing

nonpotable reuse examples

aquifer recharge, drinking water

potable reuse examples

athletic fields, parks, landscaping

reclaimed reuse examples

dissolved

substance in water where only liquid is present

suspended

substance in water where liquids and solids are present

turbidity

the degree to which light is reflected through water

law of conservation of mass

matter can neither be created nor destroyed

batch reactor

no flows in or out, completely mixed

completely mixed flow reactor

CMFR

CMFR

flow rates in and out, instantaneously and completely mixed

plug flow reactor

PFR

PFR

flow rates in and out, complete mixing in a cross section, but not in longitudinal direction

strength

ability to resist failure under load

hardness

resistance to scratching, wear, and indentation

ductility

ability to deform before breaking

brittleness

breaks with little deformation

corrosion

deterioration of a metal due to chemical reactions

compatibility

ability of a material to resist degradation