Study sets, textbooks, questions
Upgrade to remove ads
CE 326 Exam 2
Terms in this set (81)
What fraction of the world's population is affected by water born illness?
How many death happen each day due to water-borne illness worldwide?
How many billion gallons of water is used daily in the US?
What three things account for 7% of public water usage?
True or false: there is a 40/60 split between surface and ground water used in the US?
False. It is 50/50
What percentage of Iowa drinking water is from surface water?
What is the average water usage per day of an Iowan?
What are 3 physical characteristics of water?
What are 4 chemical characteristics of water?
What is an indicatory organism?
It is an organism that is often seen when a certain pathogen is present.
safe to drink
water tastes good
# moles per L (M) or [ ] in mol/L
What is the equation for equivalent weight (EW)?
How do you find a species as mg/L as CaCO3?
mg/L as species*(EW CaCO3/ EW species)
Maximum Contaminant Level
This is a regulated standard
maximum contaminant level goal
Is not regulated, just a desired concentration.
May not always be attainable.
presence of suspended matter
What is the MCL for turbidity?
Nephelometric Turbidity Unit
These measure how light scatters to determine how much suspended matter there is.
may indicate presence of organic mater
will dissociate completely
will partly dissociate
What is the equation for finding Ka in an acid-base reaction?
What are the 2 dissociations of carbonic acid?
What is the ka of HCO3^-?
What is the ka of HCO3^2-?
What is the alkalinity formula?
alk=(HCO3^-) + (CO3^2-) + (OH^-) - (H^+) in mg/L as CaCO3
the sum of polyvalent cations like Ca^2+, Mg^2+, Mn^2+, Fe^2+, etc.
True or false: Hardness is a health concern.
What are downsides of hard water?
Causes scaling and may interfere with washing.
List 10 inorganic contaminates
What causes methemoglobinemia (aka blue baby syndrome)?
What inorganic contaminate may cause heart and kidney issues?
What inorganic contaminate is harmful even at small quantities?
What inorganic compound leaves an undesirable taste?
What inorganic compound acts as a laxative?
Volatile Organic Compound
synthetic organic compound
What are some examples of THMs?
Total Trihalomethanes. Compounds that are produced when organic matter in water reacts with chlorine disinfectants.
Safe Drinking Water Act of 1974
What was included in SDWA?
MCL-primary standards to protect human health; secondary standards to provide aesthetics
it set a timeline for promulgation of new standards
gave a def. of TT, called for disinfection of all water supplies, prohibited lead in dist. systems, SWTR, and protection of ground water sources.
Surface Water Treatment Rule
states all surface waters must be filtered
1996 amendments to SDWA included
-small sys. exemptions
-disinfection byproduct rule
What is the goal of groundwater treatment?
to remove hardness
How can you remove hardness?
What is the main goal of surface water treatment?
remove color and turbidity
How does one remove turbidity?
Adding alum for coagulation and then flocculation
What does adding alum cause to happen on suspended matter?
It changes the net negative charge to a neutral surface charge
What is coagulation?
It is surface charge neutralization that encourages suspended matter to collect together.
What are two pieces of equipment used to measure surface charge?
streaming current meter and zeta potential meter
Order disinfection methods from strongest to weakest
ozone & UV > chlorine dioxide > chlorine > chloramines
Order disinfection methods from longest lasing to least long lasting.
chloramines > chlorine > chlorine dioxide >> ozone & UV
What are type of pathogens?
protozoan cysts, cryptosporidium giardia, spore forming bacteria, vegetative bacteria & viruses (from most to least concerning)
concentration * time
Why do we disinfect ground water?
Because cross connections leave systems susceptible to backflow
thin layer of material separating substances based on chemical and physical properties
How do membranes work?
High pressure on one side drives water across the membrane to the other
What are 5 types of membrane techniques?
thin film composites
True or false: as size of a membrane goes down the cost and pressure go up
What are 4 key design factors of a membrane?
-recovery=permeate flow/feed flow
removes salts from brackish or salt water and SOCs
Similar to reverse osmosis but not as effective at removing dissolved solids. Nanofilters are commonly referred to as membrane softeners because they will usually reject the double-positively charged hardness ions (i.e., calcium and magnesium) fairly well but cannot reject the single-positive charged soft ions (e.g., sodium and potassium).
Remove color and DBP
demineralization and softening
turbidity and pathogen removal
Granular Activated Carbon
powdered activated carbon
How is GAC used?
may be in a separate adsorption tank or may replace anthracite in dual media filter
replace every 1-3 yrs
How is PAC used?
Added prior to sedimentation around the tail end of flocculation
dose < 10 mg/L
What is the surface area of activated carbon?
What is activated carbon or adsorption good at removing?
SOC, VOC, DBP, DBP precursors (color)
What does Chick's Law state?
the rate of bacterial destruction is directly proportional to the # or organisms remaining at any time
dn/dt = -kN
What is a residual?
the concentration of disinfectant in the distribution system
What is the Rose equation used for?
headloss in a filter
Sets with similar terms
ERM 440 Exam 2
Other sets by this creator
ENV E 426 Quiz 6
ENV E 426 Quiz 5
CE 306 Exam 2 Fall 2020
Other Quizlet sets
Biology 11A Chapter 15: Module Questions