Questions and Answers
What is the most common reason for wastewater to contain intermittent large amounts of sand, gravel, and grit?
Combined wastewater is defined as?
Sanitary wastewater and stormwater runoff
In general, what is the solids content in wastewater?
0.1%
In general, what is the percentage of suspended solids in the total amount of solids?
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Generally, what is the percentage of dissolved solids in the total amount of solids?
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Which type of organisms would most probably be associated with poor treatment or young biomass?
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Which type of organisms would most probably be associated with very clear plant effluent, low BOD and low amounts of suspended solids?
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Aerobic bacteria will reproduce and live in an environment that contains only?
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Anaerobic bacteria will reproduce and live only in an environment that completely lacks?
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The biochemical oxygen demand (BOD) test usually has a specific time of?
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An Imhoff cone measures?
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Septic conditions are caused by?
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Scum is usually removed in the _____ treatment stage.
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When domestic wastewater enters natural waters, what species deplete most of the oxygen?
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Once the oxygen is depleted in a natural body of water, which organisms take over?
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The major gas produced by anaerobic decomposition is?
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Another name for primary treatment is?
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Digester gas is _______ when mixed with air in the proper proportions.
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A pond that is used to treat raw wastewater is called?
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A pond that has an aerobic top layer and an anaerobic bottom layer is called?
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What is the angle of the bars on a manually cleaned bar screen?
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What is the angle of the bars on a mechanically cleaned bar screen?
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What is the ideal wastewater velocity in FPS through a screen channel?
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What is the ideal wastewater velocity in FPS for grit removal in a grit chamber?
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In general, what is the water content of screen material?
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What is the wastewater velocity range in FPS for grit removal in a grit chamber?
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Which one of the following chemicals gives water its greatest capacity to neutralize acids?
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The bar rack is used?
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Typically, what is the average detention time for wastewater in a primary clarifier?
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Name one gas that irritates the eyes.
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Activated sludge clarifiers accept material to be settled from?
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Study Notes
WasteWater Sources & Characteristics
- Storm events are the primary cause of wastewater containing large amounts of sand, gravel, and grit.
- Combined wastewater consists of sanitary wastewater and stormwater runoff.
- Wastewater typically has a solids content of approximately 0.1%.
- Out of total solids in wastewater, around 30% is made up of suspended solids.
- Dissolved solids usually constitute about 70% of the total solids.
- Poor treatment or young biomass is often indicated by the presence of amoebas.
- Stalked ciliates are associated with very clear plant effluent, characterized by low BOD and minimal suspended solids.
Basic WasteWater Treatment
- Aerobic bacteria thrive in environments with only oxygen.
- Anaerobic bacteria require environments free of dissolved oxygen.
- The biochemical oxygen demand (BOD) test is commonly conducted over a 5-day period.
- An Imhoff cone is used to measure the volume of settleable solids in wastewater.
- Septic conditions occur due to the activity of anaerobic bacteria.
- Scum is typically removed during the primary treatment stage.
- When domestic wastewater is released into natural waters, aerobic bacteria deplete most oxygen.
- Once oxygen is depleted, anaerobic organisms take over in the water body.
- Methane is the primary gas produced through anaerobic decomposition.
Wastewater Treatment Facilities
- Primary treatment is also referred to as sedimentation.
- Digester gas can be extremely explosive when mixed with air in the right proportions.
- A waste stabilization pond is utilized for treating raw wastewater.
- A facultative pond features an aerobic top layer and an anaerobic bottom layer.
Preliminary Treatment
- Manually cleaned bar screens are set at a 30-degree angle.
- Mechanically cleaned bar screens are oriented at angles between 45-60 degrees.
- The ideal wastewater velocity through a screen channel is 1.5 feet per second (fps).
- For grit removal in a grit chamber, the ideal velocity is 1.0 fps.
- Screen material generally has a water content of about 80%.
- The velocity range for effective grit removal in a grit chamber is between 0.7 and 1.4 fps.
Racks, Screens, Comminutors, and Grit Removal
- Hydroxide provides water with its highest capacity for neutralizing acids.
- Bar racks are employed when bar screens are temporarily out of service.
Primary Sedimentation
- The average detention time for wastewater in a primary clarifier is typically around 2 hours.
- Material for activated sludge clarifiers is sourced from an aeration tank.
- Chlorine gas is known to irritate the eyes.
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Description
Prepare for the WasteWater Operator Certification with these informative flashcards designed for Grade 1. Each card covers essential topics such as wastewater sources and characteristics, helping you grasp key concepts necessary for certification. Use this study guide to familiarize yourself with important definitions and terms in the wastewater field.
