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REHS Wastewater

QuestionAnswer
Degradation Visible evidence of destruction of water quality
Decomposition Anaerobic state of bacterial degradation, no dissolved oxygen in water.
Recovery Water's restoration of dissolved oxygen
Digestion of Sludge Process which turns highly volatile and reactive raw organic solid matter into stable organic matter
Sanitary Sewer System The series of pipes that waste is flushed through. Waste water from the most remote part of the country must travel to the waste water facility WITHIN TWO DAYS. Water must travel 2 Feet Per Second or it becomes septic.
Septic Tank A self contained tank where solid waste is separated from the water and the water is filtered into the ground.
How Far Apart Are Manholes Supposed To Be For Checking Leaks? 300-500 Feet
How much water does an average American use for personal use a day? 50-100 gallons
When is the heaviest flow of sewage through the waste water treatment plant? Between 3-9PM.
5 Waste Water Types 1. Domestic 2. Industrial 3. Ground Water 4. Storm Drain Runoff 5. Municipal Waste
Industrial Waste Waste coming from manufacturing plant, restaurants, refineries, plating processes, etc.
Ground Water Waste that can infiltrate into the sewer by the cracks in the sewer system
Storm Drain Runoff Water generated from rain storms and ground water runoff. National Pollution Discharge Elimination System prohibits draining of any type of wastewater onto public streets.
Municipal Waste Any sewage or waste water that is going to be treated in a municipal waste water plant.
Leachate The liquid waste coming out of the ground at refuse landfills. It is the waste water from a refuse landfill. Can also be referred to as the liquid that gets dumped at a landfill.
Fresh Waste Water (Gray Water) 99.8% liquid, with .2% soilds. 50% is putrescible (organically degradable) If the putresible waste isn't treated it produces foul odors and can develop algal blooms if it enters a lake.
Septic Water Usually a black color with rotten egg smell (hydrogen sulfide). Septic means without air, and the water is undergoing anaerobic decomposition.
Waste Water Physical Characteristics 6.0-9.0. Usually enters at 6.5-8.0 at the plant.
Types of Solids in Waste Water 1. Organic (Carbon, oxygen, and hydrogen) 2. Inorganic (Minerals, gravels, dirt, silt) 3. Suspended Solids (Visible suspension that can be removed by sedimentation/filtration) 4. Colloidal (Minute solid matter that remains in suspension) 5. Sal
Hot Zone Bacteria (Thermophillic) Thrives in warm to hot environments. Thermophillic: Grows at high temperatures (113-158F) Thermoduric: Heat resistant bacteria
Medium Zone Bacteria (Mesophilic) Cool to warm environments. Mesophilic bacteria grow at 59F-112F
Cold Zone Bacteria (Psychrophillic) Thrives in cold environments at 35F-50F
Saprophytic Bacteria General bacterias that thrive on dead organic matter
Waste Water Disposal Methods 1. Surface Disposal 2. Tile Fields Disposal 3. Subsurface Disposal 4. Dilution Disposal
Surface Disposal Surface disposal pipes drain liquid onto land
Tile Fields Disposal Shallow in ground collection of pipes or tiles segmented loosely in ground allows treated water to percolate into ground. Not good for high ground water situations
Subsurface Disposal Leach lines laid 2-5 Feet Underground releases treated waste water through perforated pipes. Leach lines usually 4 inches thick
Dilution Disposal Disposal into big body of water
Preliminary Treatment Bar Screening: Removes paper, rags,large objects Grit removal: takes out sand Pre-aeration: Freshens water by introducing Oxygen. Removes oil and scum Flow meter: Records rate of water Chlorine: Can be used if water is active or reactive
Primary Treatment Sedimentation. Use of clarification tanks to remove solids that can settle and other floating debris. 1) Scum, oil, foam removal 2) Sedimentation Tanks 3) Chemical Flocculation Feed 4) Aeration tanks
Secondary Treatment Collects raw sludge and locates it to another treatment site or area for sludge digestion. Also further removes solids and dissolved solids of waste water
Tertiary Treatment Usually doesn't happen after large bodies of water as Secondary Treatment is enough. Tertiary treatment beautifies water. Filtration: Uses filters to remove particles, colors, and odors Disinfection: Treats waste water to destroy pathogenic bacte
Biological Treatment Processes (AEROBIC) 1. Activated Sludge 2. Trickling Filter 3. Oxidation Ponds 4. Composting 5. Subsurface Disposal Field
Biological Treatment Processes (ANAEROBIC) 1. Sludge Digestion 2. Methane production 3. Septic Tanks 4. Composting
Bar Screen Preliminary Treatment to remove large solids. Metal grate with thick straining bars spaced 1-3 inches. Usually paper and rags. Accumulated paper waste and rags fed to COMMINUTOR device to grind them up and gets transported to landfills.
Grit Chamber Preliminary treatment. Slows velocity of incoming waste water by allowing heavier solids to settle out quickly Abrasive grit can damage pipes. Usually has 2 chambers. Retention 1 Minute in each chamber, automatic cleaning system.
Scum, Foam, and Oil Removal Primary Treatment. Foam, oil, scum collected from top layer as water slows. "Scum skimmers" used. Paddles used to move top layer and routes it to another tank or is pumped out.
Sedimentation Tanks or Clarification Tanks Primary Treatment Used to settle out smaller suspended particles from water and organic from inorganic. Retention time 1-2 hours. Flocculants and polymers can be mixed here to aid in process. Solids collected is called sludge
Chemical Feed Units for Flocculation and Coagulation Primary Treatment. Chemical flocculation clums up harder to settle smaller solids in water. Common products are alum, electrolytic polymers, and bentonite. Process quickly mixes the flocculants and allows them to clump and settle out as sludge
Aeration Tanks Primary Treatment. Oxygenates water to promote aerobic bacteria growth.
Quality of Water Judged By 3 Things 1. Biological Oxygen Demand (BOD) 2. Total Solids 3. Volatile Solids
Biological Oxygen Demand Measurement of oxidation reduction potential by bacteria. Measured the dissolved oxygen level of waste water that would be used up by them during aerobic oxidation. Cold temps: Less active bacteria, more DO. Warm temps: More active bacteria, less DO
BOD TEST Measured over 5 day period at 20 Degrees C to determine strength of sewage. Has control and test group. Samples are refrigerated at 4C before tests. BOD is the difference of readings between control and incubated samples.
Chemical Oxygen Test (CO Test) Chemicals deplete oxygen in water, test is used to test for the Chemical Oxygen Demand. Tests for CO2 levels.
Temp Effect on Dissolved Oxygen Levels Cold water holds more dissolved oxygen than warm water.
Trickling Filter/Bio Filter Used in large community systems. Plastic filter grids that provide more surface area than old system with rocks. Water sprayed over filter bed, the waste water trickles down the filter and aerobic bacteria living on medium oxidize the organic waste.
Alternative to Bio-filtration (AERATION: NATURAL FLOCCULATION) Oxygen introduction allows aerobic bacteria grow and oxidize and clump together (FLOCCULATION). The clumped up materials get heavier and sink to the bottom of the aeration tanks as RAW SLUDGE. Devices at bottom of tank push the sludge into another tank
Stabilization Ponds/Lagoonization Used to hold large volume of water for period of time at shallow depths (3-5 feet) to promote aerobic activity and purify. Nitrogen and Phosphorous present to promote algae growth. Has to be held 45 days - 60 days before being used.
Raw sludge Fresh sewage solids and organic decomposition hasn't taken place yet. Collected at sedimentation and aeration tanks. Most biologically reactive and will putrify immediately. Must be handled quickly and efficiently
Activated Sludge Contains bacterial agents that can digest the sludge into organic materials. AKA "Mixed Liquor," also very reactive and can degrade rapidly.
Digested Sludge Product of total digestion (anaerobic) process. Most stable, as most organics have been oxidized. Resembles coffee grounds and can be added to soil.
Raw Sludge Digestion Process 1) Digestion: Oxygen removed to create anaerobic environment in tanks. Heat applied. 2. Sludge in Acidic State: Gas forming bacteria digest sludge into inorganic material HUMUS. 3. Incineration
Pit Privy Alternative disposal system which is a simple hole dug in ground to dispose waste. Most primitive, should only be used in emergency
Cesspools Now illegal to build, but legal to have existing. Similar design to well but waste water is designed into ground from cesspool vault. Overflow cuz too much liquid leaches out, solids form at bottom and saturate with sludge, and aren't pumped enough.
Seepage Pit Like a cesspool but only waste water that went through first part of treatment from septic tank goes through this to slowly leache out
Septic Tank Holds water for 24 hrs and 60-70% sludge forms at bottom. Liquid capacity determined by number of bedrooms. Not good for a place with high water table or flooded easily. Anaerobic bacteria digest the nutrients in waste water system. Must be pumped.
Imhoff Tank Specifically designed inverted cone shaped septic tank used to settle out solids quickly from water.
Septic Tank Construction Constructed from concrete box underground. Main purpose is to separate solids from liquids. The time the waste water spends in tank is "Net time". Usually 24 hours for single family, bigger place is 12 hours.
Disadvantages to Septic Tank -Sludge and scum can build up and can block off system -Improperly operating tank can oversaturate the surrounding ground water system and cause it to overflow -Pooly designed system can be very bad if not designed well because of poor porosity conditio
How often to do you need to pump a septic tank? Once every 3 years
Septic Tank Capacity Factors -Capacity is based on number of bedrooms the residence has -Usage factor is based on number of people -3 bedroom house needs 1,000 gallons -2 bedrooms needs 750 gallons -Number of leach lines branches depend on PERC tests
PERC Test Determines porosity of soil via ground absorption factor -Bacterial levels decline with depth. 5 ft percolation soil is SAFE FILTERING MEDIUM. -Hole dug using auger with 4-12 in. Depth 2-3 ft. and perforated. Let saturate for 24 hours "saturation perio
Absorption Tile Field/Leach Lines Effluent from septic tank taken out via leach lines. Leach line pipes laid out loosely so liquid can leach at controlled rate. -"Distribution/junction box" used to divert effluent into different areas
Tracer Dye Fluoresceine tracer dyes used to detect direct sewage leaks. -Bright fluorescent green/orange tablets are put in sinks/toilets with suspected leaks. When mixture is flushed it will show leaking areas
pH Meters Monitors illegal dumping activity as it monitors strong acids and bases in sewer system
What does purple pipe mean? Reclaimed water
What does yellow pipe mean? Steam, gas or oil
What does green pipe mean? Sewer
What does blue pipe mean? Potable water
What does Red pipe mean? Electrical
What does white pipe mean? Leach line
Created by: beakedcrusada on 2011-07-09



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