Wasser- und Abwassertechnologien
Theorie aus Vorlesung und Übung
Theorie aus Vorlesung und Übung
Set of flashcards Details
Flashcards | 36 |
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Language | English |
Category | Biology |
Level | University |
Created / Updated | 25.04.2016 / 10.05.2025 |
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What is the overall goal of water framework directive (WFD)?
- expanding the scope of water protection to all waters, surface waters and groundwater
- achieving "good status" for all waters by a set deadline
- water management based on river basins
- "combined approach" of emission limit values and quality standards
- getting the prices right - full cost recovery
- getting the citizen involved more closely, public participation
- streamlining legislation
Which kind of mechanical separation pinciples are there?
- Densitiy difference: sedimentation, centrifugation
- Adhesion of solids or gases on surface: flotation, deep bed filtration
- Retention on the filter surface by steric hindrance: surface filtration
- Dewatering by filters (filter press: surface filtration)
Definition of TSS
Total suspended solids, mg/l, the concentration of insoluble material in water or waste water
Definition of TDS
Total dissilved solids, mg/l, concentration of alll materials present in solution (survives filtration through a filter with 0.45müm pores)
Defiition of MLSS
Mixed liquor suspended solids, mg/l,
- suspended solids concentration on the mixed liquor in an activated dludge plant
- consists mostly of microorganisms and non-biodegradable suspended matter
Definition of TOC
Total organic carbon, mg/l as C, measure of the concentration of carbon derived from organic matter in water or waste water
Definition of DOC
Dissolved organic carbnon, mg/l,
What are pressures on surface water bodies?
Quality from diffuse sources, mainly agriculture
Hydromorphological, mainly from hydropower, navigation, agriculture, flood protection, urban development
Types of separators
Lamellae separator
- high rate of clarification
- not appliacable to water with too much salt
- increased area for separation by a stack of inclined parallel plates
- inclination ca 60°
Centrifuge
What are the conditions for the adhesion of particels on gas bubbles or porous solid systems and what kind of contact mechanisms are there?
- contact of the particle with the collector
- adhesion of the particle on the collector
- Barrier effect (Interception)
- sedimentation
- diffusion (Brownian motion)
Which membrane processes do you know? What is the related particle/molecular size and the operation pressure?
Which components/particles etc. are retained by the different membrane processes?
- Reverse osmisis: monovalent ions, moleculse (water still goes through)
- Nanofiltration: dissolved, org. substances, divalent ions
- Ultrafiltration: viruses, colloids, macromolecules
- Microfiltration: Partiicles, algae, protozoa, bacteria
What are performance limiting phenomena in membrane processes?
- Irreversible cake layer: adsorbtion, compaction, precipitation
- Pore blocking: particle diameter
- Inner pore adsorption: permeable substances with affinity to membrane material
- Biofouling: MO in film consisting of EPS
What thermal processes can be applied in water and waste water treatment? What is the physical property that drives the respective separation process?
What is the anthropogenic water cycle?
The antropogenic water cycle is made by humans, where they use the water for different purposes.
For what is the most water used in the anthropogenic water cycle?
- Irrigation in agriculture!!!
- cooling in industry
- recreation
- transportation
How is the total global water divided up?
96,5% Oceans, 2,5% Fresh water, 0,07% Saline lakes, 0,93% Saline groundwater
How is the freshwater divided up?
68,8% Glaciers and ice caps, 30,1% Groundwater, 1,3% Surface water and other freshwater
Of what does waste water consist of?
- domestic effluent including black water (toilet water) and grey water (washing/sink water)
- water from commercial establishments and institutions
- industrial effluent
- storm water and other urban run-off
Name the constitutents of waste water.
- depends on the origin of waste water
- Sum parameters for similar substances are defined and analyzed in one method for simplified characterization
- Biological effect parameters charaterize the toxicity for different endpoints (organisms, types of effect)
Which waste water parameters do exist?
- Physical parameters: Temperature, flow rate, total dissolved solids (TDS), total suspended solids (TSS), turbidity etc.
- Organoleptic parameters: Taste, odour, etc.
- General chemical parameters: pH, dissolved oxygen (DO), nitrogen, phosphorous etc.
- Organic chemical parameters:Biochemical oxygen demand (BOD), total organic carbon (TOC), absorbable organic halogens (AOX) etc.
- Microbiological parameters: Bacteria count, viruses, protozoae, algae
- Biological effect-parameters: Toxicity on bacteria, daphnia, fish etc
Harmful effects of waste water on canals
Concrete corrosion cause by acids, sulfates and sludge settling
Harmful effects of waste water on waste water treatment plants
Toxic effect on bacteria
- Mostly connected to high pollutant concentrations and limited biological degradability
- Bacterial toxicity: e.g. antibiotics, disinfectants, acids, bases, preservatives and heavy metals (toxicity depends on concentration)
- Very sensitive: nitrification step in waste water treatment plants (WWTP) due
to inhibition of nitrifying bacteria - Toxic effect on bacteria is described as dilution factor
Harmful effects of waste water on recieving water bodies
Eutrophication
- Main reason: elevated concentrations of N- and P- compounds which are
limiting growth factors in many water bodies - Eutrophication refers particularly to the increased growth of algae, which
causes depletion of oxygen
Fish polulation
- Acute fish toxic substances, e.g. ammonium
- Substances, which destroy the food chain of fishes, so-called „daphnia
toxic“ substances - „Persistent“ (not used in the metabolism) substances which accumulate in
the food chain and can cause long-term damages
Aquatic ecosystems/ Biodiversity
- Acute or chronic toxic effects on individual or several species of the ecosystems
- An effect on the most sensitive species can destroy the ecological balance, which also influences less sensitive species
Name processes for water and waste water treatment
- physical: sedimentation, membrane processes, filtration, flotation
- physico-chemical: precipitation/flocculation, adsorption, ion exchange
- thermal: stripping/destillation, extraction, concentration by evaporation
- chemical: incineration, wet oxidation
- biological: aerobic, anaerobic
Advanced waste water treatment options
- oxidative processes: ozonation
- membrane processes: reverse osmosis
- biotechnological processes: enzymatic processes
- adsorption: activated carbon
Name characteristics of industrial waste water (Chemical industry)
- Poor biological degradability: High residence times (15 h instead of 3-4 h)
- Higher raw COD: High energy consumption (energy efficient oxygen supply required); Aeration by injection, tower biology
- Odor problem (Housing and exhaust air treatment required)
- Toxic peaks possible (Monitoring of toxicity, huge buffer tanks)
- Poor sedimentation of sludge (post-treatment by flotation)
- Sludge is not disposable (incineration necessary)
- typically: huge tank volume, high flexibility of operation
Name origins of intustrial waste water of the chemical industry
Pesticieds, dyes, adhesives/paintings, plastics, textile fibers, soaps/detergents, metallic compounds, fertilizer, mineral oil and basic chemicals
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