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42 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Indicators of water organic pollutants
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BOD
COD |
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reasons why wastewater should be treated before discharge or reuse
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safeguard public health
environmental protection enable reuse extract nutrients of potential use |
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How many people per hour lose their life due to waterborne diseases? 50, 100, 150, 200, 2000, 5000
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200
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Approximate number of people around the world which do not currently have access to sanitation?
2.6 x 10^7 x 10^8 x 10^9 x 10^10 |
2.6 x 10^9 de 7 x 10^9
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4 facets that assist the extensive implementation of sanitation facilities within industrialized countries and the challenges which limit the implementation in developing countries
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Institutional support
Strict control Financial funding Public perception |
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What is a population equivalent? Mention some numbers
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A average amount of oxygen consuming components (54 g of BOD or 136 g of TOC) that a person discharges in the wastewater
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Describe the treatment process
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Steps to go from the influent to the effluent
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How many times the dry weather flow should the max hydraulic capacity of a wastewater treatment plant should be?
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3-5 x Qdwf-max
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Qdwf-max
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For the netherlands case what is...
Qdwf-d Qdwf-max Qdwf-gen Qdwf-min |
Qdwf-d 120 - 140 l/inh/day
Qdwf-max Qdwf-d/12 or 14 Qdwf-gen Qdwf-d/24 Qdwf-min Qdwf-d/48 |
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Types of solids found in wastewater
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inert solids
volatile solids dissolved, suspended and settleable solids |
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types of biodegradable compounds and non biodegradable in ww
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biodegradable: organic compounds like pts chos and fats, and organic nitrogen compounds
non biodegradable: inorganic compounds like salts, acids, bases, sludge. and organics like hormones and pharmaceuticals |
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toxic substances in ww
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organics like pesticides
inorganic like metals |
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What is the classification of solids by size? and How to measure them?
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>0.1 micras visible or settleable, sedimentation for 2 hours
1-100nm colloidal, 105 drying <1 nm dissolved, filtration |
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What is a colloidal particle?
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A negative charge particle that do not settle and measures between 1 and 100nm
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What is BOD?
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The biochemical oxygen demand is the amount of oxygen necessary to transform biochemically oxydizable elements by means of bacteria in one liter of water
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What is COD?
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The chemical oxygen demand is the amount of oxygen necessary to transform all the oxydizable elements by means of chemicals like pottasium dichromate in one liter of water
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Examples of extended treatment
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chlorination
membrane filtration Activated carbón Filtración Ion exchange Chemical precipitations |
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Which contaminants cause oxygen deppletion? 5
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Coarse particles and settleable solids
Biodegradable solids Inorganic nutr like nitrate phosphate Suspended particles Ammonia |
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What is the difference between a combined and a separate sewer system?
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A separate sewer system treats urban, municipal and industrial ww, a combined system includes the rain. Here the rain water flow determines the maximum hydraulic load in the sewage treatment plant
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Why removing organic matter and nutrients from wastewater?
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Because many of them lead to oxygen deppletion
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What is the approximate average ww production in netherlands per capita based on dwf
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150
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What is the approximate maximum ww flow in netherlands per capita which forms the basis of rain weather flow conditions?
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750
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Factors that influence the carrying capacity of water? 7
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Chemical nature of compounds
polarity Max solubility of substances degree of ionization local weather conditions flow velocity in sewer pipes type and characteristics of the sewage |
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Of the polluting material in ww which percentage is organic?
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60 - 80 %
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Indicate the separation method
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imhoff evaporation filter evaporation muffle
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Which elements are defined as kjeldahl nitrogen?
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organic nitrogen, ammonia and ammonium
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What is the concentration of e coli found in the following types of water?
Swimming Influent Freshwater Effluent Drinking Coast |
Swimming 100 cfu/100ml
Influent 300000 cfu/100ml Freshwater 1000 cfu/100ml Effluent 6000 cfu/100ml Drinking 1 cfu/100ml Coast 200 cfu/100ml |
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Chemicals used for COD
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Pottasium dichromate as oxidizing agente
Silver sulphate as catalyst Mercury sulphate to prevent chloride oxidation |
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Toxic substances affect BOD or COD?
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BOD
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Steps for ammonia to turn into nitrate
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2
First by means of nitrosomonas, ammonia reacts with oxygen to form nitrite Second step by means of nitrobacter fron nitrite to nitrate |
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The dissolved oxygen concentration depends on
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Air oxygen concentration
Air pressure Water temperature Oxygen consumption rate |
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Ways of natural reaeration
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Photosynthesis
Diffusive oxygen transport |
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Reaeration rate depends on
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temperature
surface/volume ratio turbulence flow velocity |
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What happened in the blue and green curve?
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Blue curve: Low aeration rate
Green curve: Low BOD degradation rate |
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Disadvantages of pond systems
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Not able to cope with high organic pollution loads
Require a significant amount of area |
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The more the temperature, the less oxygen?
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TRUE
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What does it mean that COD/BOD is above or below 2
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Below 2: aerobic treatability
Above 2: less treatable water, maybe because of toxic compounds |
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Why is oxygen necessary to treat organic matter?
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Chemically because while carbon oxidizes, oxygen is reduced
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How is it called when there is difference between Max O2 solubility and actual O2 concentration?
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Oxygen deficit, once it occurs there is passive difusión for oxygen from air to liquid
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In nature, ponds can recover themselves when organic pollutants get to them? How do they do it?
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The dissolved oxygen is reduced and carbon is oxidized by bacterias which form new cells, phosphate, ammonia and CO2, algae use that to form new cells and produce O2
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What is the alternative to ponds when I have a more concentrated sewage?
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Anaerobic pond to stabilize organics
Less deep facultative pond Maturation pond to restore O2 |
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Molar and mass basis formula for COD
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