CA Wastewater Grade V Exam Questions with Verified Answers| Latest Update Graded A+
How can incompatible industrial waste affect the environment? CECs like personal care
products and pharmaceuticals can cause environmental damage when passed into receiving
waters, while flammable or explosive liquids can be harmful to both collection systems and
treatment plant operators.
What does the National Pretreatment Program make illegal? The National Pretreatment
Program makes it illegal to discharge incompatible waste.
Industrial Wastewater Treatment & Nutrient Addition - Additive Industrial wastewater is
high in BOD but low in nutrients.
May cause filamentous or non-filamentous bulking like fungi or algae.
Some filamentous bulking ("slime bulking") is present when BOD is high & nutrients are low.
Making activated sludge buoyant, hard to settle.
Indian ink is used to identify.
Balanced microbial growth ratio 100:5:1 BOD 100: Nitrogen 5: phosphorous 1 (100 mg/L: 5
mg/L: 1 mg/L)
I&I Infiltration - Groundwater, which rises after rainfalls, seeps/trickles/flows into pipes,
manholes or other structures through holes, cracks, joint failures, faulty connections.
Inflow - Stormwater from aboveground sources intentionally or unintentionally.
I & I - Problems The cost of transporting.
Washout - Causing high BOD, TSS & grit (first flush).
Loss of hydraulic capacity in sewers which lead to SSO's.
Dilution in BOD & TSS, making it difficult to meet the BOD & TSS 85% removal plant efficiency.
Loss of hydraulic loading in wastewater treatment plants equal short detention time's.
A moratorium on new sewer connections, with a loss in revenue.
,I & I - Addressing problems 1. Collection system maintenance.
2. Monitoring.
3. Identification with smoke and CCTV.
4. Prioritization and corrective action: Sewer lining, sewer replacement, manhole
repair/replacement. Notify property owners of illegal connections.
Oxidation Reduction Potential (ORP) Oxidation - Loss of electrons of bacteria & viruses.
Reduction - Gain of electrons such as Cl2.
ORP Is used for chlorine and other disinfectants and chemicals. ORP Probe can be used for
nitrification and denitrification.
ORP Measurements help with over and under feeding.
The ORP Probe is used to deliver chlorine as demand fluctuates.
When the sensing probe goes above set point, chlorine dose decreases.
When the sensing probe drops below set point, chlorine dose increases.
In dichlorination, dose is used by another ORP probe for dichlorination.
ORP probe placement: Due to chlorine reaction time, the probe needs to be placed
downstream, but not so far to where poor disinfection occurs. Oxidizing agent gets reduced,
reducing agent gets oxidized.
Ultraviolet (UV) Disinfection Due to the expense of using chlorine disinfection, stricter
regulations on handling, storage and safety concerns, UV disinfection has been the better
alternative. At certain wavelengths of the EMR Spectrum, UV interacts with bacteria and viruses
DNA and RNA, making them unable to replicate.
UV system components. 1. Low pressure - low intensity lamps (most common).
2. Quartz sleeves protect lamps while still providing UV radiation transmission.
3. Ballast controls the voltage to the lamps.
4. Intensity probes.
5. Control system.
,6. Channels with flow control such as valves and gates.
7. Acid bath tank for cleaning.
What effects UV Dose? Water clarity measured in percent UVT, filters reduce needed dose.
Water hardness: Ca2+ and Mg2+ are measured as hardness, Ca2+ can precipitate CaCO3 (a
problem in both mesophilic and thermophilic digesters as well).
Frequency of UV lamp cleaning: Fouling from calcium carbonate and algae hurts UV
performance.
UV Dose Units of dose = mW x s / cm2
mJ = mW.s
mW - Power delivered to the lamps.
s - Exposure time.
Primary clarification: Process objective of primary clarification. Is to remove floatable and
settleable particles.
The removal of settleable's greatly impact downstream process in both liquid and solid
treatment train.
Dissolve solids are not particle solids.
Particles are taken to be solids visible to the human eye.
Visible particles are captured on a 1.2 μm filter.
Solids via Filtration - Colloids 0.001 - 1.0 μm Solids that pass through a 1.2 μm filter are
defined as TDS.
Sugar is organic, salt is inorganic.
Organics, dissolved or particulate, burn at 550 degrees Celsius (aka VS).
TS can be broken up into TSS and TDS by filtration.
Both TSS and TDS can separately be burned at 550 degrees Celsius, exposing what's VSS/ISS and
VDS/IDS.
, Colloids 0.001 - 1.0 μm may get caught or passed through the filter.
If you can see it, it's not colloids, TDS are not particle solids.
All settleable solids are TSS, but not all TSS is settleable.
Primary Clarification - Organics & Solids The focus is not just solids, but organics removed in
the primaries.
Influent TSS = TSS set or TSS non-set.
Each particle contains organics and inorganics.
TSS set = VSS set + ISS set
TSS non = VSS non + ISS non.
BOD - via filtraion measure sBOD & pBOD
pBOD - The organics captured on the glass fiber filter.
pBOD = sBOD - Total BOD
VSS & pBOD - Represent organic material associated with solids.
VSS & pBOD TSS set: VSS set = pBOD & ISS set
TSS non: VSS non = pBOD & ISS non
VSS is pBOD
VSS non = pBOD
VSS set = pBOD set
pBOD removal is important to Digesters & AB's.
BOD (via filtration) measures pBOD & sBOD.
Primary [Performance] - TSS removal & BOD removal Primaries can only remove TSS.set
(VSS.set & pBOD set)
Primary effluent contains [TSS.non = VSS (pBOD) + ISS non] & [sBOD].
Optimum primary performance is when TSS = TSS non & when BOD = BOD non.
40 to 60 % of TSS are TSS set (and also removed).
How can incompatible industrial waste affect the environment? CECs like personal care
products and pharmaceuticals can cause environmental damage when passed into receiving
waters, while flammable or explosive liquids can be harmful to both collection systems and
treatment plant operators.
What does the National Pretreatment Program make illegal? The National Pretreatment
Program makes it illegal to discharge incompatible waste.
Industrial Wastewater Treatment & Nutrient Addition - Additive Industrial wastewater is
high in BOD but low in nutrients.
May cause filamentous or non-filamentous bulking like fungi or algae.
Some filamentous bulking ("slime bulking") is present when BOD is high & nutrients are low.
Making activated sludge buoyant, hard to settle.
Indian ink is used to identify.
Balanced microbial growth ratio 100:5:1 BOD 100: Nitrogen 5: phosphorous 1 (100 mg/L: 5
mg/L: 1 mg/L)
I&I Infiltration - Groundwater, which rises after rainfalls, seeps/trickles/flows into pipes,
manholes or other structures through holes, cracks, joint failures, faulty connections.
Inflow - Stormwater from aboveground sources intentionally or unintentionally.
I & I - Problems The cost of transporting.
Washout - Causing high BOD, TSS & grit (first flush).
Loss of hydraulic capacity in sewers which lead to SSO's.
Dilution in BOD & TSS, making it difficult to meet the BOD & TSS 85% removal plant efficiency.
Loss of hydraulic loading in wastewater treatment plants equal short detention time's.
A moratorium on new sewer connections, with a loss in revenue.
,I & I - Addressing problems 1. Collection system maintenance.
2. Monitoring.
3. Identification with smoke and CCTV.
4. Prioritization and corrective action: Sewer lining, sewer replacement, manhole
repair/replacement. Notify property owners of illegal connections.
Oxidation Reduction Potential (ORP) Oxidation - Loss of electrons of bacteria & viruses.
Reduction - Gain of electrons such as Cl2.
ORP Is used for chlorine and other disinfectants and chemicals. ORP Probe can be used for
nitrification and denitrification.
ORP Measurements help with over and under feeding.
The ORP Probe is used to deliver chlorine as demand fluctuates.
When the sensing probe goes above set point, chlorine dose decreases.
When the sensing probe drops below set point, chlorine dose increases.
In dichlorination, dose is used by another ORP probe for dichlorination.
ORP probe placement: Due to chlorine reaction time, the probe needs to be placed
downstream, but not so far to where poor disinfection occurs. Oxidizing agent gets reduced,
reducing agent gets oxidized.
Ultraviolet (UV) Disinfection Due to the expense of using chlorine disinfection, stricter
regulations on handling, storage and safety concerns, UV disinfection has been the better
alternative. At certain wavelengths of the EMR Spectrum, UV interacts with bacteria and viruses
DNA and RNA, making them unable to replicate.
UV system components. 1. Low pressure - low intensity lamps (most common).
2. Quartz sleeves protect lamps while still providing UV radiation transmission.
3. Ballast controls the voltage to the lamps.
4. Intensity probes.
5. Control system.
,6. Channels with flow control such as valves and gates.
7. Acid bath tank for cleaning.
What effects UV Dose? Water clarity measured in percent UVT, filters reduce needed dose.
Water hardness: Ca2+ and Mg2+ are measured as hardness, Ca2+ can precipitate CaCO3 (a
problem in both mesophilic and thermophilic digesters as well).
Frequency of UV lamp cleaning: Fouling from calcium carbonate and algae hurts UV
performance.
UV Dose Units of dose = mW x s / cm2
mJ = mW.s
mW - Power delivered to the lamps.
s - Exposure time.
Primary clarification: Process objective of primary clarification. Is to remove floatable and
settleable particles.
The removal of settleable's greatly impact downstream process in both liquid and solid
treatment train.
Dissolve solids are not particle solids.
Particles are taken to be solids visible to the human eye.
Visible particles are captured on a 1.2 μm filter.
Solids via Filtration - Colloids 0.001 - 1.0 μm Solids that pass through a 1.2 μm filter are
defined as TDS.
Sugar is organic, salt is inorganic.
Organics, dissolved or particulate, burn at 550 degrees Celsius (aka VS).
TS can be broken up into TSS and TDS by filtration.
Both TSS and TDS can separately be burned at 550 degrees Celsius, exposing what's VSS/ISS and
VDS/IDS.
, Colloids 0.001 - 1.0 μm may get caught or passed through the filter.
If you can see it, it's not colloids, TDS are not particle solids.
All settleable solids are TSS, but not all TSS is settleable.
Primary Clarification - Organics & Solids The focus is not just solids, but organics removed in
the primaries.
Influent TSS = TSS set or TSS non-set.
Each particle contains organics and inorganics.
TSS set = VSS set + ISS set
TSS non = VSS non + ISS non.
BOD - via filtraion measure sBOD & pBOD
pBOD - The organics captured on the glass fiber filter.
pBOD = sBOD - Total BOD
VSS & pBOD - Represent organic material associated with solids.
VSS & pBOD TSS set: VSS set = pBOD & ISS set
TSS non: VSS non = pBOD & ISS non
VSS is pBOD
VSS non = pBOD
VSS set = pBOD set
pBOD removal is important to Digesters & AB's.
BOD (via filtration) measures pBOD & sBOD.
Primary [Performance] - TSS removal & BOD removal Primaries can only remove TSS.set
(VSS.set & pBOD set)
Primary effluent contains [TSS.non = VSS (pBOD) + ISS non] & [sBOD].
Optimum primary performance is when TSS = TSS non & when BOD = BOD non.
40 to 60 % of TSS are TSS set (and also removed).
