Texas Wastewater Treatment Study Guide Exam, Exams of Water and Wastewater Engineering

Download Texas Wastewater Treatment Study Guide Exam and more Exams Water and Wastewater Engineering in PDF only on Docsity! Texas Wastewater Class A (Test 3) Texas Wastewater Class A (Test 3) Containing 143 Questions and Answers Updated 2024-2025. (Dark Back Ground for better Visibility and eye Care) What removes Total Suspended Solids from a sample (TSS) - Answer: filtration What chapter of the Texas Water Code gives T C E Q authority to control discharges in Texas. - Answer: Chapter 26 1 Texas Wastewater Class A (Test 3) Inorganic solids include - Answer: sand, grit and minerals Organic solids include - Answer: organic materials from plants, animals or humans A good plant influent pH is about - Answer: 7.2 A simple method for indicating when to waste sludge is - Answer: 30-minute settling test What is the expected organic loading of a stabilization pond and what is the detention time in days? - Answer: 35 pounds, of B O D, per acre, per day, and a detention time of 30 Days Calcium Hypochlorite or HTH, is a - Answer: strong Oxidizer and reacts violently with oil and hydro carbons. When added to water what does chlorine form - Answer: it forms Hypochlorite, and Hydrochloric acid When ammonia is present in wastewater and reacts with chlorine what is formed - Answer: When ammonia is present in wastewater, and reacts with chlorine, Chloramines are formed. 2 Texas Wastewater Class A (Test 3) Pre-treatment of wastewater would include: - Answer: Coarse or fine screening, grinding and grit removal and grease removal and pre-aeration Primary treatment of wastewater would include - Answer: settling tanks or basins, scum collection and removal, sludge collection and removal Solids in wastewater are classified as - Answer: Total: solids or residual (TR), Suspended (TSS), Dissolved (TDS), Settleable (SS), Non-setteable, Floatable, Organic and Inorganic Total Suspended Solids (TSS) are those that - Answer: Can be filtered out Total Dissolved Solids (TDS) are those that - Answer: cannot be filtered out Settable Solids - Answer: Settle out when left standing for extended periods of time Non-settleable Solids are - Answer: Small particles that do not settle Volatile Solids (VSS) are those that - Answer: Are determined by burning the residue from the Total Solids determination 5 Texas Wastewater Class A (Test 3) Inorganic Solids (ash) are those that - Answer: Consist of sand, grit, & minerals and can be suspended or dissolved Organic matter, in wastewater, can be dissolved, or suspended ,and make up approximately - Answer: 65 % , of the total solids The typical pH of an influent entering the plant will vary from - Answer: 6.5 to 8.0 Acute toxicity occurs when - Answer: There is a rapid die off of treatment organisms Chronic toxicity occurs when - Answer: Certain microorganisms become inactivated but others continue to work resulting in a sick biological process A mechanical device that screens & cuts large solids in small particles - Answer: Comminutors There are five (5) major components to a trickling filter - Answer: Filter floor, underdrain, walls, filter media, & distributer arms Zoogleal Mass refers to - Answer: A thick layer of jelly like slime where organisms bacteria, fungi, 6 Texas Wastewater Class A (Test 3) protozoa and ciliates thrive. The efficiency of a trickling filter is measured in - Answer: Percent BOD Removed Common operating problems with a trickling filter include - Answer: Ponding, Filter files, Odors, Clogging of Nozzles, and Snails Wastewater Stabilization Ponds are an approved process for wastewater treatment. Organic loading of Stabilization Ponds is typically - Answer: 35 pounds of b. o .d. with a minimum, of 30 days detention time Wastewater Stabilization Ponds work through a complex process which includes - Answer: Sunlight, Oxygen, Nutrients, Algae, and Bacteria Facultative Lagoons have two zones of treatment - Answer: an aerobic surface layer and an anaerobic bottom layer In a Facultative Lagoon, typically one could expect - Answer: 50% B O D removal, The most common method of dewatering and drying sludge is - Answer: drying bed 7 Texas Wastewater Class A (Test 3) the pounds of MLVSS in the ___________. - Answer: Dividing/ Incoming BOD/ aeration tank In the activated sludge process, the term Gould Sludge Age refers to - Answer: How long in days a pound of solids stays in the aerator In the activated sludge process, Gould Sludge Age (GSA) is calculated by - Answer: Dividing the total pounds of TSS in the aerator by the pounds of TSS entering the aerator as raw In the activated sludge process, the term Mean Cell Residence Time (MCRT) refers to - Answer: The amount of time the living cells are kept in the plant In the activated sludge process, daily observation of the aeration basin treatment processes are essential. The operator should pay close attention to - Answer: Surface turbulence, Foam, Odors, & Color In the activated sludge process, daily observation of the final clarifier is also essential. The operator should pay close attention to - Answer: Surface scum, Sludge blanket, Weir Flow, Rising solids, & Clarifier overflow In the activated sludge process, five (5) Important control parameters are - Answer: Dissolved Oxygen level, Aerator solids level, Solids quality, Rate of returned sludge, & Wasting rate 10 Texas Wastewater Class A (Test 3) In the activated sludge process, Sludge Rising differs from "Sludge Bulking" and "Sludge Rising" is typically associated - Answer: Nitrification - De-nitrification process In the activated sludge process, techniques used to reduce "Frothing & Foaming" typically include - Answer: Adjusting sludge age, Reducing the amount of air, Spraying the frothing area with water, Applying de-foaming agents In the activated sludge process, floc is very important to the settling process. Floc is composed primarily of - Answer: Bacteria, Protozoa, Microscopic Animals, & Fungi In the activated sludge plants, the operator will experience problems. Some of the common Treatment plant problems include - Answer: Insufficent capacity, Equipment failures, Design inadequacies, Poor maintenance, & Inflow rates exceed plant capacities. In the activated sludge plants, the operator will experience problems. Some common Operational problems include - Answer: Sludge quality, foaming, improper operating techniques In the activated sludge plants, the operator will experience problems. Some common Environmental problems include. - Answer: Low temperatures, System pH out of range, & Excessive algae growth 11 Texas Wastewater Class A (Test 3) In the activated sludge plants, to properly set the clarifier return rate the operator must know three things - Answer: Return activated sludge rate, Sludge blanket thickness, & the Solids concentration of the return flow The typical sludge age for extended aeration plants is - Answer: 20 to 40 days In the activated sludge plant, good quality sludge will settle - Answer: Gently and Uniformly in 15 to 20 minutes In the activated sludge plant, old sludge quality will settle - Answer: Rapidly, and ragged in 5 minute period. In the activated sludge plant, there are 5 important nitrogen transformation processes that occur by microorganisms. They are - Answer: Assimilation, Ammonification, Nitrification, Denitrification, and Nitrogen fixation. In the activated sludge system, "Hydraulic Wash Out" is - Answer: When the upward movement of the water in the clarifier exceeds the downward settling velocity In the activated sludge system, Hydraulic Wash Out can be controlled by - Answer: flow equalization, Additional clarifier capacity or inflow reduction 12 Texas Wastewater Class A (Test 3) A good Primary Clarifier removes __ to __% of settable solids. - Answer: 90 to 95% Good Sludge has Lots of __ & ___ ___, a Few ___ and __. - Answer: ciliates & free swimmers, a few rotifers, and flagellates. What process is used to re-seed Aeration Basins and remove solids from Secondary Claifires? - Answer: Return Activated Sludge (RAS) A Sludge Volume Index (SVI) number of ___ is an indication of sludge bulking. - Answer: 180 mL/g Digesters show improvement by an increase in - Answer: methane, and a decrease CO2 Primary treatment uses - Answer: gravity to treat ___ and below is an oxygen deficient atmosphere. - Answer: 19.5% What will not affect the vacuum filter system? - Answer: Drum speed Information on preventive maintenance procedures, materials, and frequencies for plant structures should be taken from? - Answer: Manufactures literature What is the minimum surface loading rate on a trickling filter? - Answer: 1 MG/Acre/Day Standard Rate Filter 15 Texas Wastewater Class A (Test 3) What type of process requires scum from the final clarifier to be place in the digester? - Answer: Trickling filter and Rotating Biological Contactor (RBC) What is the assumed BOD removal rate used in plant design calculations for primary clarifiers? - Answer: 35% What is the name of the algae that is abundant in stabilization ponds? - Answer: Phytoplankton What regulates the RPM's on an air driven Rotating Biological Contactor (RBC)? - Answer: Air volume On a water lubricated pump, what should the seal water pressure be? - Answer: 5 p s i over stuffing box pressure Increasing the return rate of a conventional activated sludge plant has what effect on process control? - Answer: Decrease detention time, in aeration basin, raise dissolved oxygen, lower sludge blanket. If an employee, is guilty of misconduct, as defined by the utilities personnel policies, the supervisor should? - Answer: Attempt to modify, the employee's behavior , 16 Texas Wastewater Class A (Test 3) through training ,and other forms of assistance, ,and inform the employee , of the consequences. In a stability pond, what is density stratification? - Answer: Warm water being lighter the cool water remains near the surface, thus producing a layered effect. What clarifiers have maximum surface loading at peak and design flow? - Answer: Primary and intermediate What gives pistons longer wear? - Answer: Longer stokes and slower RPM's. What do you use to run a 30 minute settling test? - Answer: 1000 milliter graduated cylinder. Which process is more like an oxidation pond? - Answer: Extended aeration Carbon dioxide does not harm - Answer: mucous membranes or your lungs What meter measures resistance? - Answer: Ohm meter What are the limits of authority for a line manager position? - Answer: Supervises their subordinates only 17