TEXAS WASTEWATER D COMPREHENSIVE EXAM UPDATED
QUESTIONS AND SOLUTIONS RATED A+
✔✔Primary Clarifiers Inspection - ✔✔Primary clarifiers should be drained and inspected
annually.
✔✔Primary Sludge Fermentation - ✔✔Primary sludge fermentation is used in plants that
are required to remove phosphorus from the wastewater.
✔✔Volatile Fatty Acids Production - ✔✔Sludge will ferment and produce volatile fatty
acids to aid with phosphorus removal when allowed to accumulate for 3 to 5 days in a
clarifier.
✔✔Biomass - ✔✔A mass or clump of organic material consisting of living organisms
feeding on the wastes in wastewater, dead organisms and other debris.
✔✔Distributor - ✔✔The rotating mechanism that distributes the wastewater evenly over
the surface of a trickling filter or other process unit.
✔✔Microorganisms - ✔✔Very small organisms that can be seen only through a
microscope. Some microorganisms use the wastes in wastewater for food and thus
remove or alter much of the undesirable matter.
✔✔Nitrification - ✔✔An aerobic process in which bacteria change the ammonia and
organic nitrogen in wastewater into oxidized nitrogen (usually nitrate). The second-stage
BOD is sometimes referred to as the 'nitrogenous BOD' (first-stage BOD is called
'carbonaceous BOD').
✔✔Ponding - ✔✔A condition occurring on trickling filters when the hollow spaces (voids)
become plugged to the extent that water passage through the filter is inadequate.
Ponding may be the result of excessive slime growths, trash, or media breakdown.
✔✔Recirculation - ✔✔The return of part of the effluent from a treatment process to the
incoming flow.
✔✔Shock Load - ✔✔The arrival at a plant of a waste which is toxic to the organisms in
sufficient quantity or strength to cause operating problems.
✔✔Trickling Filter Media - ✔✔Rocks or other durable materials that make up the body
of the filter and provide a surface on which microorganisms can grow.
✔✔Zoogleal Film - ✔✔A complex population of organisms that form a 'slime growth' on
the trickling filter media and break down the organic matter in wastewater.
, ✔✔Trickling Filter Operation - ✔✔Trickling filter operators should use the lowest
recirculation rate possible that produces good effluent quality.
✔✔Biological Activity - ✔✔Warmer temperatures increase the biological activity of a
trickling filter zoogleal mass leading to better treatment.
✔✔Roughing Filter - ✔✔A trickling filter can be used as a roughing filter to reduce the
organic load of the wastewater prior to another biological process.
✔✔Underdrain Channel - ✔✔The underdrain channel should be drained during periods
of trickling filter shutdown to prevent odors and insect problems from developing.
✔✔Effluent BOD - ✔✔Increasing the recirculation rate will help to reduce the effluent
BOD from a trickling filter.
✔✔Hydraulic Loading - ✔✔Hydraulic loading and organic loading are two criteria used
to control trickling filter operations.
✔✔Fixed-Film Treatment Processes - ✔✔Trickling filters in their various forms are
classified as fixed-film treatment processes.
✔✔Soluble BOD - ✔✔The BOD in a waste stream that remains following filtration
through a standard glass filter.
✔✔Aerobic Microbial Population - ✔✔The aerobic microbial population consists of
bacteria, protozoa, algae, fungi and worms growing on the media.
✔✔Foul Odors - ✔✔Foul odors coming from a trickling filter is usually the result of
inadequate ventilation or lack of dissolved oxygen in the wastewater.
✔✔COD - ✔✔COD is a better indicator to use than BOD when quick results of organic
loading is required.
✔✔Air Drive Unit - ✔✔A method of causing the shaft of a RBC to rotate by using air that
is bubbled through the reaction tank.
✔✔Mechanical Drive Unit - ✔✔A traditional drive unit that uses an electric motor, drive-
chain and sprockets to rotate the shaft on a RBC.
✔✔Fixed Film Process - ✔✔A type of waste treatment process that utilizes a biomass
that is attached to a medium and is therefore said to be fixed.
QUESTIONS AND SOLUTIONS RATED A+
✔✔Primary Clarifiers Inspection - ✔✔Primary clarifiers should be drained and inspected
annually.
✔✔Primary Sludge Fermentation - ✔✔Primary sludge fermentation is used in plants that
are required to remove phosphorus from the wastewater.
✔✔Volatile Fatty Acids Production - ✔✔Sludge will ferment and produce volatile fatty
acids to aid with phosphorus removal when allowed to accumulate for 3 to 5 days in a
clarifier.
✔✔Biomass - ✔✔A mass or clump of organic material consisting of living organisms
feeding on the wastes in wastewater, dead organisms and other debris.
✔✔Distributor - ✔✔The rotating mechanism that distributes the wastewater evenly over
the surface of a trickling filter or other process unit.
✔✔Microorganisms - ✔✔Very small organisms that can be seen only through a
microscope. Some microorganisms use the wastes in wastewater for food and thus
remove or alter much of the undesirable matter.
✔✔Nitrification - ✔✔An aerobic process in which bacteria change the ammonia and
organic nitrogen in wastewater into oxidized nitrogen (usually nitrate). The second-stage
BOD is sometimes referred to as the 'nitrogenous BOD' (first-stage BOD is called
'carbonaceous BOD').
✔✔Ponding - ✔✔A condition occurring on trickling filters when the hollow spaces (voids)
become plugged to the extent that water passage through the filter is inadequate.
Ponding may be the result of excessive slime growths, trash, or media breakdown.
✔✔Recirculation - ✔✔The return of part of the effluent from a treatment process to the
incoming flow.
✔✔Shock Load - ✔✔The arrival at a plant of a waste which is toxic to the organisms in
sufficient quantity or strength to cause operating problems.
✔✔Trickling Filter Media - ✔✔Rocks or other durable materials that make up the body
of the filter and provide a surface on which microorganisms can grow.
✔✔Zoogleal Film - ✔✔A complex population of organisms that form a 'slime growth' on
the trickling filter media and break down the organic matter in wastewater.
, ✔✔Trickling Filter Operation - ✔✔Trickling filter operators should use the lowest
recirculation rate possible that produces good effluent quality.
✔✔Biological Activity - ✔✔Warmer temperatures increase the biological activity of a
trickling filter zoogleal mass leading to better treatment.
✔✔Roughing Filter - ✔✔A trickling filter can be used as a roughing filter to reduce the
organic load of the wastewater prior to another biological process.
✔✔Underdrain Channel - ✔✔The underdrain channel should be drained during periods
of trickling filter shutdown to prevent odors and insect problems from developing.
✔✔Effluent BOD - ✔✔Increasing the recirculation rate will help to reduce the effluent
BOD from a trickling filter.
✔✔Hydraulic Loading - ✔✔Hydraulic loading and organic loading are two criteria used
to control trickling filter operations.
✔✔Fixed-Film Treatment Processes - ✔✔Trickling filters in their various forms are
classified as fixed-film treatment processes.
✔✔Soluble BOD - ✔✔The BOD in a waste stream that remains following filtration
through a standard glass filter.
✔✔Aerobic Microbial Population - ✔✔The aerobic microbial population consists of
bacteria, protozoa, algae, fungi and worms growing on the media.
✔✔Foul Odors - ✔✔Foul odors coming from a trickling filter is usually the result of
inadequate ventilation or lack of dissolved oxygen in the wastewater.
✔✔COD - ✔✔COD is a better indicator to use than BOD when quick results of organic
loading is required.
✔✔Air Drive Unit - ✔✔A method of causing the shaft of a RBC to rotate by using air that
is bubbled through the reaction tank.
✔✔Mechanical Drive Unit - ✔✔A traditional drive unit that uses an electric motor, drive-
chain and sprockets to rotate the shaft on a RBC.
✔✔Fixed Film Process - ✔✔A type of waste treatment process that utilizes a biomass
that is attached to a medium and is therefore said to be fixed.
