Drinking Water Flashcards
The discharge from filters flows into a storage reservoir also called a
a Clearwell
What technique is effective at removing 50 to 95% of the algae that is from the influent water
microstrainer
Which of the followING is needed to determine the minimum fire suppression storage?
required fire flow rate and the duration of fire flow rate
what are the four main zones of the settling tank
inlet, sludge, settling and outlet
Which of the following types of settling occurs when individual particles settle independently
Discrete
which of the following terms describes the surface charge that the sub-micron particles carry that cause them to repel each other so they cannot collect to form larger particles
Colloidal***
Which of the Following terms describes the pH at which the zeta potential of the particle is zero
Iso-electric point
Paddles are used to gently mix the water in the flocculator, Which is greater the velocity of the paddle or the velocity of the water?
Velocity of the paddle - this is because of the slip the slip is represented by the factor k in the equation for the water velocity
what is the most basic test used on the effectiveness of coagulation/ flocculation
jar test
Once coagulant has ben added to the treated water, the particles become net neutral. What is the forces acting to attract the particles that no net charge?
VAn der Waal forces are weak forces that work to attract particles together that have no charge
As alkalinity increases, what happens to the capacity of the water to neutralize acids
Increases - Alkalinity is the measure of how well a sample can neutralize an acid. The more alkalinity in water, the better the water can neutralize acids
What does reverse osmosis accomplish during water treatment?
It is an effective way to remove contaminants, it removes ions, molecules and large particles from drinking water.
what are the 7 basic steps for water treatment?
- Coagulation
- Flocculation
- Sedimentation
- Filtration
- Disinfection
- Storage
- Distribution
What is the purpose of aeration during drinking water treatment?
Aeration during Drinking water treatment is primarily to reduce taste and odor causing compounds in the system.
Where is the storage reservoir typically located on a suite that is also serviced by a pumping station
The storage reservoir will typically by located on the opposite side from the pumping station, During periods of high water consumption, the site can be fed from both sides which decreases the head in the mains.
What is Effective storage
it is total storage minus the dead storage
The presence of methane gas occurs in the groundwater because of the decomposition of organic matter, How is it removed?
Aeration, during the process air is mixed into the water which leads to the has being vented to the outside atmosphere
where are cyanophycean found?
both salt and fresh water, floating near the water surface
what color are cyanophycean?
they are blue-green in color
What is a main culprit of taste and odor complaints?
cyanophycean
Name three methods/ materials used for oxidation
Potassium Permanganate, Chlorine Dioxide and Ozone
What are THMs’?
Trihalomethanes, are the byproducts of the chlorination of water that has natural organic matter present
What is the technical term/ test for the amount of Odor in water
Threshold Odor number/test, determine the amount of odor in the water. During the test dilutions are presented of a sample and the last dilution in which the odor can be detected is called the threshold odor number
What are advantages of powdered activated carbon
Low initial cost and dosage flexibility
What are the disadvantages of powdered activated carbon?
large amount of sludge is produced as it cannot be regenerated
What materials cause salty taste in water
Sodium, Magnesium, Potassium
What is the most common compound used for drinking water treatment in the coagulation process
Alum, or aluminum sulfate is the most common chemicals coagulant used for drinking water treatment in coagulation process
What is the purpose of coagulation?
To remove small particulate matter that is suspended in the influent water
What is tapered flocculation
also called tapered energy - the process with which the amount of flocculation gradually diminishes as the water progresses through
Name two reasons there could be poor floc formation and a test that can be done?
Poor Flocc formation can be a symptom of either an inadequate coagulant dose or improper detention time. These can be tested using a simple jar test to model what the problem is?
Name 3 advantages of UV in disinfection for drinking water?
- does not form harmful by-products
- Does not create an unpleasant taste or odor
- Effective on a large range of pathogens
Name 3 things that help determine the location of a water treatment plant?
Location of location water, Location of power sources, Sewer services for the plant
Name 3 factors used in sizing atmospheric storage tanks?
Emergency reserve storage, future growth of the system, fire flow storage
What is the recommended standby storage for systems served by a single source supply?
two times the average day demand
What does activated carbon mainly attract from liquid and vapor?
organic materials, Activated carbon attracts only a small variety of inorganic chemicals
What chemicals are more likely to produce a rotten egg odor in drinking water
Hydrogen sulfide
What makes a garlic-y taste in water?
Methane
What is something creates a earthy or grassy odors
Geosmin
Two main categories of coagulating chemicals?
ionic polymers and hydrolyzing metal ions
What can bentonite clay be used for in the flocculation process
as an additive to weight down the flocs
What does it mean to agglomerate
gathered into a ball, mass, or cluster. specifically : clustered or growing together but not coherent.
what is the optium pH for Alum?
typical operation is 6-7 but is effective with 5.5 to 8
name 3 devices used for agitation for rapid mixing and flocculation
Mechanical agitator, pneumatic agitator and baffle basin
name three types of flocculation additives to improve flocculation?
Polymers, Colloidal clay and activated silica
the purpose of coagulation/ flocculation is to turn what into floc?
Turbidity - Settling out the floc works to eliminate the impurities that create turbidity
Can Activated carbon remove Radon?
Yes
Can Activated carbon remove Pathogens?
NO
Can Activated carbon remove VOCs?
Yes
Which of the following tpes of sedimentation occurs in the lower parts of the clariferiers when the concentration of particles is the highest
Discrete
what is an Aldehyde
an organic compound formed by the oxidation of alcohols.
The occur naturally in the environment, and are potentially/consdiered carcinogenic and mutagenic, and sometimes cause odor
What are typical aldehydes
methanol (formaldehyde) and ethanal (acetaldehyde)
How are aldehydes found in water
it orginates from many sources such as :
1. oxidation processes,
2. photochemcical transformations
3. life processes of animals and plants
4. decomposition of organic matter
5.Formed in the atmosphere, anthropenic origin.
6. By-product of disinfection with Chlorine
what is an instanteous slug dose
an addition of a chemicals to a system is one big dose, mixing then occurs
Disadvantage of this technique is very concentrated solutions and intensive mixing is required
what is the drinking water standard for methane gas
while no drinking water standard exists for methane gas however there is a warning level of 10 mg/L and levels about 28 mg/L could release flammable amounts
What are the risks of methane gas in drinking water
Methane can be flammable and explosive when mixed with oxygen.
it can also displace oxygen which would cause suffocation when released in a confined space
Can cause issues with pumps and water systems
What color and odor does methane gas have?
Colorless and odorless, and tasteless however Production-grade methane is marked by a pungent odor from mercaptan; a chemical odorant added to methane by a gas company before distribution to help in leak detection
what are some solutions for methane gas in drinking water
air stripping, aeration, and or a tall vent that would avoid any flammable or confined space hazards
What is a Phenol
mildly acidic chemical in the -OH family, usually caused by polluted waste water, Phenolic compounds are also found naturally occurring in bodies or water.
and also some phenolic compounds are associated with different colors of flowers and fruits
What is the risk of Phenols in drinkingwater
Drinking water with extremely high concentrations of phenol has caused muscle tremors, difficulty walking, and death in animals.
Methods on removing phenols from water?
adsorption, extraction, polymerisation, electro‐coagulation, photocatalytic degradation, biological methods, electro‐Fenton method, advanced oxidation processes, adsorption and ion exchange and membrane‐based separation techniques
describe Osomsis
The basics - weaker saline(salty) solution will migrate to a stronger saline solution,
Example - plant roots absorbing water for the soil and our kidneys adsorbing water from out blood
Describe Reverse Osomsis
the opposite of regular osmosis, force must be used to make this occur.
basically a solution passes through a membrane that separates dissolved solutes from water, IE salty solution moves through the filter and joins a less salty solution
What is the difference between Reverse Osmosis and Osmosis
Osmosis occurs naturally, and Reverse Osmosis must have force applied to be make process occur, also the obvious difference is Regular Osmosis makes a salty solution and Reverse makes a “cleaner” pure solution
what are two types of Rapid Sand filters
- Rapid Gravity
- Rapid Pressure
the only difference is speed
For dual media filters, what does the upper layer of coal trap do?
The upper layer of coal traps most of the large floc, and the finer sand grains in
the lower layer trap smaller impurities
Name three advantages of of Dual media filters
main advantages of multimedia filters compared to single-medium filters are longer filtration runs, higher filtration rates, and the ability to filter a water with higher turbidity and suspended solids.
What is the pore size range of ulta-filtration membranes?
pore sizes in the range of 0.02 – 0.05 micron
Ultra Filtration membranes can remove what four things?
bacteria, viruses, colloids, and silt
What is backwashing
reversing the flow of water through a home treatment device filter or membrane to clean and remove deposits
what is dredging?
removal of mud from the bottom of water bodies. This can disturb the ecosystem and cause silting that kills aquatic life. Dredging of contaminated mud can expose biota (the flora and fauna of a region) to heavy metals and other toxics. Dredging activities may be subject to regulation under state and federal laws.
define echard
water in the soil not available to plants
what is an enteric viruses
a category of viruses related to human excreta found in waterways.
what is epilimnion
warm, less dense top layer in a stratified lake. Compare hypolimnion.
what is facultative bacteria
bacteria that can live under aerobic or anaerobic condition
what is giardia lamblia
a protozoa found in the feces of infected humans and animals that can cause severe gastrointestinal ailments. It is a common contaminant of surface waters
what is halolimnic
of, like or pertaining to sea creatures who spend time in fresh water.
what is halophilous
tolerant of salt or salt-wate
hydropathy is?
study of or treating diseases with water
imhoff cone
a clear, cone-shaped container used to measure the volume of settleable solids in a specific volume of water.
interfacial tension
the strength of the film separating two immiscible fluids (e.g., oil and water) measured in dynes per, or millidynes per, centimeter.
Langelier Saturation Index (LSI)
an index reflecting the equilibrium pH of a water with respect to calcium and alkalinity; used in stabilizing water to control both corrosion and scale deposition.
Lindane
a pesticide that causes adverse health effects when present in domestic water supplies and is toxic to freshwater fish and aquatic life
methyl tertiary butyl ether (MTBE)
an additive originally put in gasoline to reduce air pollution, but later found to be a source of groundwater pollution
mixed liquor
a mixture of activated sludge and water containing organic matter undergoing treatment in an aeration tank
polychlorinated biphenyls
(PCBs)
toxic industrial chemical compound substances that were used in the manufacture of plastics and as insulating fluids in electrical transformers and capacitors. Banned since 1979, PCBs continue to be found in fish/animals
recarbonization
process in which carbon dioxide is bubbled into water being treated to lower the pH
trihalomethanes (THM)
chemical compounds in which three of the four hydrogen atoms of methane (CH4) are replaced by halogen atoms. Widely used in industry as solvents or refrigerants. THMs are also environmental pollutants, and many are considered carcinogenic. THMs are generally by-products of chlorination of drinking water that contains organic material.
vadose zone
the zone between land surface and the water table where the moisture content is less than saturation (except in the capillary fringe) and pressure is less than atmospheric. Soil pore space also typically contains air or other gases. The capillary fringe is included in the vadose zone.
CERCLA
Comprehensive Environment Response, Compensation and Liability Act. Also known as SUPERFUND. The Act gave EPA the authority to clean up abandoned, leaky hazardous waste sites.
POTW
publicly-owned treatment works - a wastewater treatment plant that is owned by a state, unit of local government or Indian tribe, usually designed to treat domestic wastewaters. The term also may include devices and systems used by those entities in the storage, treatment, recycling and reclamation of municipal sewage or liquid industrial wastes
SRF
state revolving funds - a program, capitalized in part by federal funds, that provides low-interest loans for construction of publicly owned wastewater treatment and water recycling facilities, for implementation of nonpoint source and storm drainage pollution control management programs, and for the development and implementation of estuary conservation and management programs.
EIS
Environmental Impact Statement - a document that analyzes the effects of major federal projects on the environment. Required by the National Environmental Policy Act. It must be filed with the President and the Council on Environmental Quality, and made available to the public
“first in time, first in right”
phrase indicating that older water rights have priority over more recent rights if there is not enough water to satisfy all rights
National Municipal Plan
a U.S. EPA policy created in 1984 to bring all publicly owned treatment works (POTWs) into compliance with Clean Water Act requirements
National Oil and Hazardous Substances Contingency Plan
the federal regulation that guides determination of the sites to be corrected under the Superfund program, and the program to prevent or control spills into surface waters or elsewhere.
National Pollutant Discharge Elimination System
a provision of the Clean Water Act that prohibits discharge of pollutants into waters of the United States unless a permit is issued that complies with the Clean Water Act. In Texas, the Texas Commission on Environmental Quality (TCEQ) administers the NPDES program and issues TPDES permits.
