OCT True and False T2 Questions

The purpose of filtration is to remove particulate impurities and floc from the water being treated.

True

Filtration preceded by coagulation, flocculation, and sedimentation is commonly referred to as Conventional Filtration.

True

Direct filtration is defined as consisting of coagulation, flocculation, and filtration.

True

The recommended rate of rise in a mixed media filter bed, in GPM/sq ft, is 15.0.

True

Filtration is essentially a physical and chemical process.

True

Air binding is helpful in the operation of a filter to achieving high quality effluent product water.

False

The filtration rate of a filter bed is dependent on the type of bedding selected (single media, dual media, or mixed media).

True

Poor chemical treatment can often result in either early turbidity breakthrough or rapid head loss buildup.

True

T/F: Generally, the more irregular the filter media, the slower the head loss buildup.

False.

This means that filters with irregular shapes or sizes tend to have larger void spaces, allowing for more efficient flow and reduced resistance compared to those with uniform shapes.

T/F: Mixed media filter beds are considered to be the most efficient type of filter bedding available and represent the best available technology today.

True.

This type of filter bed enhances filtration performance by combining different media types that target various contaminants, leading to improved removal efficiencies.

T/F: In mixed media filter beds, the garnet is usually found in the top layer.

False

T/F: Mixed media filter beds are generally described as “inverse filters” since the filter medias are layered from coarse at the tup to fine on the bottom.

True.

This configuration allows for optimal filtration as the coarser media captures larger particles while finer media effectively traps smaller ones.

T/F: In conventional single media (sand) filter beds, particulate matter can only penetrate the bed approximately 6 inches before reaching terminal head loss, while the entire depth of the bed is utilized in mixed media filter beds.

True.

In conventional single media filter beds, the filtration efficiency is limited due to depth restrictions, whereas mixed media filter beds utilize the entire depth, enhancing particulate matter removal.

T/F: The best way to assure high filtration efficiency is to select an effluent target value below 0.10 NTU’s and stay there.

True.

Selecting an effluent target value below 0.10 NTU ensures that the filtration system operates effectively, minimizing turbidity and improving water quality.

T/F: Dual media filters are referred to as “depth filters” while sand filters are known as “surface filters”.

True

T/F: Mixed media filter bedding is usually selected over single or dual media bedding because of longer service runs, less head loss buildup over extended service runs, greater depth of solids penetration in the bed, and overall superior performance.

True

T/F: Filter beds should be backwashed with raw water only.

False

T/F: The purpose of backwashing filters is to remove, or discharge, the entrapped solids from the filter media.

True

T/F: Water temperature is an important consideration when backwashing rates are established (higher backwash rates are required in warmer water).

True

T/F: Backwashing at too high a rate is much more destructive than at too low a rate.

True

T/F: The amount of backwash water used should not exceed 2-4% of the plant’s service run for rapid sand filters, or 6% for dual and mixed media filters.

True

T/F: In-line filtration requires coagulation, flocculation, sedimentation, and filtration steps.

False

T/F: Floc particles must be small enough to penetrate the upper filter media, large floc will cause the top portion of the filter bed to clog rapidly.

True

T/F: An efficient means of handling backwash water is to recycle it to te beginning of the plant to a point in the line before the flash mixer.

True

T/F: The degree of pretreatment required before filtration depends on the type of treatment plant constructed and the facility’s size.

True

T/F: A clean filter bed, at the start of a new service run, has a zero head loss through the bed by measurement.

False

T/F: Plant operators compare filter performance from season-to-season and from plant-to-plant by comparing the filter-run length in hours.

True

T/F: "Bumping” a filter to avoid backwashing is considered a good practice.

False

T/F: Filter efficiency is measure from either a grab sample or an Online turbidimeter.

True

T/F: Effluent turbidity levels should be checked at least once every 2 hours, or preferalby, continually recorded with an online monitor.

False

T/F: Since the size of the voids in a single media filter are uniform throughout the depth of the filter bed, effective filtration is only experience in the fist 6 to 8 inches of the bed.

True

T/F: When applied after sedimentation, cationic polymer is generally referred to as filter alum.

False

T/F: Nephelometric turbidity sample bottles should be silicone oiled occasionally, then wiped with a lint-free towel, to prevent scratching the bottles, which can produce false readings.

True

T/F: The naked eye can easily differentiate between 3.0 NTU’s and 1.0 NTU’s.

False

T/F: The appropriate emergency kit for a one ton cylinder is a “C” kid.

False

T/F: Chlorine rooms should have sealed walls, power exhaust fans that are ducted at the floor, and doors which open inward.

False

T/F: All 3 of the coliform testing methods (multiple tube fermentation, membrane filtration, and Colilert) require an initial incubation period of 24 hours, ± 2 hours.

True

T/F: A US History question. Filtration to control typhoid began in 1907, while disinfection with gas chlorine was not started until 1914 by Wallace and Tierman after liquid chlorine became available in 1909.

True

Natural water is pure.

False

T/F: Soda ash and sodium hydroxide are identical.

False

T/F: If naturally occurring fluoride in water exceeds 4.0 mg/L, osteoporosis can occur.

False

T/F: A 20-50% expansion of the filter bed is usually adequate to expand and suspend the bottom grains of filter bedding.

True

T/F: Head loss, filter-effluent turbidity levels, and the length of the filter run are parameters that can be measured to determine when the filter run should be stopped and backwashing must begin.

True

T/F: Commonly, a rate-of-flow controller is used to maintain a constant desired filtration rate, usually 2.0 GPM/sqft for rapid sand silters, and 4.0-6.0 GPM/sqft for high-rate filters.

True

T/F: Diatomaceous eath filters can be operated as either pressure or vacuum filters.

True

T/F: Filtration rates for diatomaceous earth filters are usually between 2-3 GPM/sqft.

False

T/F: Slow sand silters were first introduced into the US in 1993 and are the newest type of filter technology.

False

T/F: A one ton chlorine tank has 4 threaded fusible plugs installed in the ends of the tank.

False

T/F: The basic safety rule to follow prior to opening any chemical container, or using any water treatment chemical is to read the label.

True

T/F: When chlorine reacts with moisture, it forms two acids: hydrochloric and acetic acids.

False

T/F: The titrant in a DOD test kit is phenylarsene oxide solution since it is very stable.

False

T/F: A community water service serves 10 or less service connections for 90 days or more per year.

False

T/F: Oxygen levels under 19.5% are adequate for workers’ respiratory needs when performing work in a confined space.

False

T/F: The leading cause of death in confined spaces is being struck by falling objects.

FalseT/F:

T/F: An air gap is a cross-connection device.

False

T/F: Pump cavitation is a system problem.

True

T/F: Tip cavitation is not as severe as suction (eye) cavitation.

False

T/F: High nitrates in ground water is a sign of pollution.

True

T/F: The presence of coliform bacteria in drinking water is an absolute indication that pathogens are present.

False

T/F: All coliforms are pathogenic.

False

T/F: Iron and manganese are classified under the SDWA Primary Drinking Water standards.

False

T/F: Activated carbon should always be stored in separate, closed rooms since it removes oxygen from the surrounding atmosphere while in storage.

True

T/F: ICR stands for Information Collection Rule.

True

T/F: An operator should always carefully wipe the mouth and stopper of a sample bottle before taking a sample for bacteriological analysis.

False

T/F: Plain sedimentation, or settling, is one of the fundamental water treatment surface water processes.

True

T/F: Air vents are usually installed at low points in a distribution system to periodically remove stagnant water.

False

T/F: Water free of taste, odors, and color is always safe to drink.

False

T/F: Polyelectrolytes are compounds with long chain molecules, which are used as coagulants, coagulant aids, and filter aids.

True

T/F: Acitvated carbon in PAC form can be used to remove dissolved organic chemicals and THM precursors often found in surface waters.

True

T/F: The number of monthly samples for coliform bacteria is based on the population served.

True

T/F: Corrosive water can release lead from lead solder and lead piping.

True

T/F: Water plant operators are required to maintain a daily plant operating log book in pencil.

False

T/F: The flocculation paddle peed should be increased considerably during cold weather periods.

False

T/F: The presence of dissolved iron and manganese in a water supply may stimulate growth of certain micro-organisms.

True

T/F: When potassium permanganate (KMnO₄) is used to control taste and odor, some method of filtration is necessary to remove the insoluble manganese oxides formed during the treatment process.

True

T/F: As temperature goes up, the required Ct goes up.

False

T/F: Legionella is common in surface waters and grows particularly well at temp’s around 49^oC (120^oF).

True

T/F: The presence of any amount of gas in the multiple fermentation coliform test constitutes a positive sample.

True

T/F: Softened water and distilled water are comparable in TDS content.

False

T/F: Volatile organic chemicals (VOC’s) are generally described as contamination of groundwater from solvents.

True

T/F: Lead and copper samples must be collected from consumer taps.

True

T/F: Turbidity is a measure of the cloudiness of water caused by suspended material.

True

T/F: Micro-organisms include bacteria, viruses, and protozoa, some of which cause disease.

True

T/F: There are 3 major types of requirements in the SDWA: sampling/reporting, record keeping, and public notification.

True

T/F: The minimum number of filters that must be installed in a water plant is 3.

False

T/F: Filter mudballs are caused when backwash rates are set too high.

False

T/F: Zinc orthophosphate, sodium silicate, and sodium hydroxide can be added to finished water to control corrosion in distribution systems.

True

T/F: Non-carbonate hardness is due to salts of calcium and magnesium while carbonate hardness is due to the presence of bicarbonates and carbonates.

True

T/F: An MCLG is a non-enforceable standard.

True

T/F: Oocysts are associated with Cryptosporidium, whereas cysts are associated with Giardia lamblia.

True

T/F: Effective filtration proce4sses for the removal of Cryptospiridium are: a conventional surface water treatment plant, or dissolved air floatation (DAF).

True

T/F: The suggested EPA action level for Cryptospiridium is in the range of 10-40 oocysts/100 Liters.

True

T/F: Dissolved oxygen, pH, and temperature have little effect on the rate of corrosion.

False

T/F: Cathodic protection is an electrical method for killing pathogenic bacteria.

False

T/F: One advantage of using chloramination in large distribution systems is the ability to maintain a chlorine residual at the end of long pipe runs.

True

T/F: In the presence of direct sunlight, chlorine residuals will decrease rapidly.

False

T/F: Even though raw water contains little-to-no alkalinity, a good floc can usually be formed simply by adding alum in greater quantity.

True

T/F: Gentle stirring in the coagulation process is helpful, but violent mixing is required to achieve complete flocculation.

False

T/F: Within a groundwater aquifer of low to moderate permeability, bacterial pollution will travel further than chemical pollution.

False

T/F: The colder the water, the faster the floc will settle.

False