Wastewater Treatment Processes and Equipment Quiz

Domestic wastewater is also called ______ wastewater

Industrial wastewater is wastewater in which ______ wastes predominate

The infiltration/Inflow water that enters the sewer system through leaking joints, cracks and breaks, or porous walls is called ______

Storm water is runoff resulting from ______ and snowmelt

Three types of sewer systems are: sanitary sewer system, storm sewer system, and ______ water system.

The contaminants of concern in wastewater treatment include suspended solids, biodegradable organics, pathogens, nutrients, priority pollutants, refractory organics, heavy metals, and dissolved ______.

The treatment objectives for wastewater treatment are the removal of suspended and floatable material, treatment of biodegradable organics, elimination of pathogenic organisms, removal of toxic compounds, and removal of ______.

Wastewater treatment systems are divided into preliminary, primary, secondary, tertiary, and solids treatment and ______.

Preliminary wastewater treatment involves the removal of large solids to prevent damage to the remainder of the unit operations through screening, comminution, grit removal, and ______.

Primary wastewater treatment aims to remove a portion of suspended solids and organic matter by settling or sedimentation, typically removing about 60% of solids and 30% of ______.

Secondary wastewater treatment is directed principally at the removal of biodegradable organics and suspended solids, including biological treatment by activated sludge, fixed-film reactors, lagoons, and ______ systems.

Tertiary wastewater treatment involves the polishing of secondary effluent, primarily removing nutrients, toxic compounds, increased amounts of organic material, and suspended ______.

Solids treatment and disposal includes the collection, stabilization, and subsequent disposal of the solids removed by other ______.

Wastewater treatment methods are classified into physical unit operations, chemical unit processes, and ______ unit processes.

Preliminary treatment includes screening, the first operation performed on incoming wastewater for the purpose of removing materials that might damage equipment or hinder further ______.

Screening devices are used to remove coarse solids from wastewater, which consist of sticks, rags, boards, and other large objects that find their way to the wastewater collection ______.

Optimum range of dissolved oxygen for aerobic processes is 1.5 – 2.5 mg/L

Dissolved oxygen levels of 5-6 can lead to undesirable ______ and filamentous bulking in the sludge, a condition known as over-aeration.

Operational and wastewater characteristic factors can cause filamentous bulking in secondary clarifiers.

Operational causes of non-filamentous organisms include over-aeration and the presence of ______.

Various cures and techniques can be employed to address issues such as adjusting ______ and DO levels, dosing with H2O2, and pre-treating wastewater.

Aeration techniques include the use of air diffusers and ______, each with its unique advantages and limitations.

Wastewater ponds and lagoons are used for natural purification processes, with ______ often referred to as polishing or tertiary ponds.

Attached growth systems, such as ______ and biotowers, are populated by a variety of organisms and are effective in treating wastewater.

Trickling filters utilize randomly ______ and are simple with low operating costs but may have odor and clogging problems.

Biotowers use ______ in a vertical arrangement and are suitable for higher porosity and low weight.

The success of an ______ is often dependent on the performance of the final clarifier.

The presence of oxygen in ponds is primarily provided by ______, and lagoons are distinguished from ponds by artificial aeration to provide oxygen.

Biological wastewater treatment involves the use of microorganisms to convert organics in wastewater into ______ or biomass.

The rate of biomass production and food utilization in biological treatment is affected by factors such as temperature, pH, toxins, salt concentration, oxidants, and ______.

Microorganisms involved in biological treatment require a gradual adjustment to a wide range of environmental factors and may be irreparably damaged by sudden ______.

The design of biological systems for wastewater treatment requires knowledge of biological principles, kinetics of metabolism, mass balance principles, and ______ operations.

The two types of biological growth/culture used in wastewater treatment are suspended cultures/growth and ______ growth.

Design parameters/operational parameters in the activated sludge process include F/M ratio, MLSS, MCRT/SRT, and ______, which affect treatment efficiency and waste activated sludge production.

The F/M ratio in biological treatment measures organic loading and affects aeration period and treatment efficiency, with low ratios resulting in high treatment efficiency and little waste activated ______.

MLSS represents the suspended solids in the reactor and is useful in the determination of F/M, sometimes expressed in terms of suspended ______.

The MCRT/SRT represents the average time in which microorganisms or solids stay in the reactor, and HRT represents the average time in which the liquid remains in the ______.

Wastewater treatment systems such as activated sludge, ponds, and lagoons utilize suspended cultures/growth, with variations such as step aeration, tapered aeration, contact stabilization, pure oxygen activated sludge, oxidation ditch, high rate, and extended ______.

The microorganisms involved in biological treatment are the same as those in natural freshwater systems but are carefully controlled in engineered reactors to optimize organic ______.

Biological treatment of wastewater requires a wide variety of organisms or a mixed culture due to the wide variety of ______ present in wastewater.

Fine ______ consist of woven wire or cloth perforated plates and should be mechanically cleaned on a continuous basis.

Mechanically-cleaned bar ______ have bar racks 3 to 4 inches apart, while manually-cleaned bar ______ require good flow distribution and velocity control.

Disposal methods for ______ include hauling to disposal areas, burial on the plant site, incineration, disposal with municipal solid wastes, and grinding and returning to the wastewater flow.

Comminution involves shredding ______ to approximately 8 mm in size using devices like a hammermill or a barminutor.

Grit ______ is essential to separate non-biodegradable solids from organic suspended solids, and it includes channel-type horizontal-flow grit chambers, aerated grit chambers, and vortex-type grit chambers.

Grit ______ protect mechanical equipment, reduce heavy deposits, and minimize the frequency of digester cleaning.

Parshall ______ and Palmer-Bowlus ______ are commonly used for flow measurement in wastewater treatment.

Primary ______ involves sedimentation, which separates suspended particles from water through gravitational settling in sedimentation basins or tanks.

Factors affecting sedimentation tank ______ include the type of solids, age of wastewater, rate of solids flow, cleanliness, and mechanical condition of the tank.

______ achieves removal efficiency for settleable solids (90-95%), suspended solids (50-65%), BOD (20-35%), and colloidal solids (not removed unless coagulants are added).

Flow distribution in sedimentation ______ is managed by inlet structures to evenly distribute the flow and prevent short circuiting.

Secondary ______ involves the biological conversion of dissolved and colloidal organics into biomass, which can be subsequently removed by sedimentation.