Biology and waste management Flashcards
You will still need to learn the cells from week 2
What is environmental engineering concerned with?
- procision of safe, palatable and ample public water supplies
- proper disposal of or recycling of wastewater and solid wastes
- control of water, soil and atmospheric pollution
- sustainable sources of renewable energy
- resource management and circular economy for materials
- sustainable food production
Why do we need environmental engineering?
Population growth places heavy demand on natrual resources, such as water and soil
Population also results in higher consumption of energy, food and commodities
Also increase waste generation
What is the hydrological cycle
- Land and ocean precipitation
- percolation
- surface and ground water flow
- flow goes to ocean
- ocean and land evaporation (and transpiration)
What percentage of the worlds water is fresh?
0.8
How much fresh water does irrigation use?
70%
How much fresh water does industry use?
19%
How much fresh water is used domestically?
11%
What are the effects of increasing population/ urbaisation on water resources?
- Pollution and reiver desiccation
- Overcommitted water resources
- Groundwater levels declining rapidly in densely populated areas
- degredation of land and water resources through erosion, pollution, salinization nutrient depletion, and seawater intrusion
- irrigation in developing countries has improved economic growth, damages environment
- climate change affects temperature and precipitation, equatorial countries effected most
- Urbanization increases the demand for water and generates mrore wastewater, required more food etc.
How many people (in 2015) did not have access to improved sanitary facilities?
2.3 billion
How many people (in 2015) did not have access to a safe water supply?
2.1 billion
What bacteria’ cause intestinal disease?
- Salmonela
- Shigella
- Yersinia
- Vibrio Cholerae
- Campylobacter jejuni
- Escherichia coli
- Listeria
What Protozoa cause intestinal disease?
- Cryptosporidium
- Entamoeba histolytica
- giardia lamblia
- balantidium coli
- toxoplasma gondii
What enteric vriruses cause intestinal disease?
- Hepatitis A and E
- Adenovirus
- Norovirus
- Enteroviruses
- Polio virsues
- Coxsackie viruses
- Echoviruses
- Enteroviruses
- Reoviruses
- Astroviruses
What halminth worms cause intestinal disease?
- Ascaris umbricoides
- ascaris suum
- trichuris trichirua
- toxocara canis
- taenia saginata
- taennia solium
- necator americanus
- hymnolepis nana
What diseases can poor water supply and sanitation cause?
- Diarrhoea
- Intestical worms
- Trachoma
- Schistosomiasis
How many people get and die from diarrhoea a year?
4 billion get it
1.5 million die
How many people have intestinal worms?
1.5 billion
How many people have trachoma?
1.9 million
How many people have schistosomiasis?
230 million
What is the lifecycle of schistomasis?
- found in feces and uring
- Eggs hatch releasing mracidia
- Miracidia penetrate snail tissue
- Spyrocysts in snails
- Cercairae released by snail into water
- penetrates skin
- cnecariae lose tails and become schistosomulae
- circulation
- migrate to portal blood in liver and mature into aduls
- Paired adult worms migrate to bowel/ rectum and lay eggs
What will the effects of climate change be in the UK?
- cooler, drier sumers
- warmer, wetter winters
- more extreme weather events
- increased flooding risk
What are he main sources of GHGs?
Transport, agriculture, industy and power generation
What is the main emitter of CH4?
Waste disposal
What are the effects of poor waste management?
- Potentially hazardous
- strong link to GHG emissions and climate change
What can we gain from waste management?
- Control over environmental emissions
- energy recover
- recover value from dispose resources
- recover value from biodegradeable waste
How much waste is generated in europe?
2.5 billion tonnes
How much waste is disposed to landfill in europe?
1.2 billion tonnes
What are the 2 main priorities in waste management?
first priority - protect human health/ environment
second priority - resource recovery to promote circular economy
What is the triangle involved in the EU waste framework directive?
biggest to smallest:
product:
- prevention
All waste:
- preparing for re-use (use materials repeatedly)
-recycling (use materials to make new products)
- recovery (incinerate waste to recover energy)
- disposal (safely dispose of waste to landfill or incineration without energy recovery)
What are some key takeaways from the waste management of landfills?
- resource recovery curbs GHG emissions but disposal increases them (CH4 from landfill and BC from uncontrolled burning)
- regulatory policy aims to reduce waste and disposal and increase recycling
- Landfil Directive to reduce disposal of biodegradable municipal solid waste
- Improved waste management could reduce global GHGs up to 20%
What are some positive takeaways from effective waste management?
- Landfill disposal has declined and recycling has increased in the UK and Eu
- UK has met EU targets for biodegradable waste disposal in landfill
- UK GHG emissions from MSW have decreased significantly
What characteristics distinguish living organisms?
- Responsiveness
- Growth
- Reproduction
- Metabolism
- Movement
- Excretion
- Cell
How do prokaryotes differ from eukaryotes?
They lack a nuclear membrane and a cell nucleus. Prokaryotes also lack most of the intracellular organelles and structures that occur in eukaryotic cells
How large are prokaryotic cells?
0.5 -5 um
What is catobolism?
Energy production in cells
Releases ATP by breaking complex molecules into simple molecules
What is anabolism?
The assimilation, growth and repair of cells
External C substrate – Energy utilised + assimilation –> new cellular material
What is metabolism?
The sum of anabolism and catobolism
What does ATP stand for?
Adenosine triphosphate
How do Anabolic pathways ATP?
utlize ATP to provide energy for the synthesis of monomeric compounds that are required for the manufacture of small molecules needed in cells - carbohydrates, lipids , amino acids, nucleotides, vitamins etc.
What are the types of metabolism?
Autotrophic, heterotrophs
What are the different kinds of autotrophs?
Photoautotrophs - energy from light
photosynthetic bateria
Chemoautotrophs - energy from chemicals
- Iron, sulphur, hydrogen… bacteria
What are different kinds of heterotrophs?
Photoheterotrophs - bacteria Chemotheterotrophs - most bacteria - protozoans - fungi - animals
What are the three different steps in energy production?
- Glycolysis - First step in the respiration of sugar
- Kreb’s - series of reactions releasing ATP
- Electron transport chain - couples a series of chemical reactions
What are the two different types of respiration?
- Aerobic
- Anerobic
How does cell division work in prokaryotes?
Binary Fission
How long does it take a bacteria cell to divide?
20-30 minutes
How do Eukaryotes reproduce?
By both sexual and asexual reproduction
What is Asexual reproduction in cells called?
Mitosis
Parent cell - DNA replicates - 2 daughter cells
What is sexual reproduction in cells called?
Meiosis
(parent cell- DNA replicates - 2 daughter cells - 4 daughter cells
What is the defining feature of a faculative anerobe?
Do not require 02 to grow
Swithc to alternative electron acceptors when 02 is defficient
What is the defining feature for obligate aerobes?
Can only grow in the presence of O2
What are the defining features of obligate anaerobes?
Cannot tolerate the presence of O2 and die when exposed to it
Only use alternative electron acceptors to O2
What is the effect of water on the rate of growth of cells?
- Highly sensitive to changes in the osmotic potential of the surrounding environment
- solutes in cytoplasm maintain a OP below their surroundings
- Water availability reduced by interaction with solute molecules (salt/sugar molecules)
- Salinity or drying prevent microbial growth
What is the process for urban water treatment?
- Bar screen removes large debris
- grit tank removes small debris
- setting tank allows suspended particles to settle out of water or watewater
[water goes to 4, solid to ] - clarifier
- UV and chemical treatment [ clean goes to recieving water or 6]
- Digester - produces energy or is incinerated or used in agriculture
What determines the effectiveness of wastewater treatment?
amount of contaminants
- preliminary screening remoes solid matter
- primary settlement removes suspended soils
- secondary biological treatment and settlement reduces the organic matter content
- tertiary treatemtn - effluent polishing step: reduce the load of micro-organisms and or nutrients in the effluent
How much BOD, suspended solids, nitrogen and phosporous does primary settlement remove?
40% of BOD
60% of suspended solids
17% of nitrogen
20% of solids
How much BOD, suspended solids, nitrogen and phosphorous does secondary treatment remove?
95% of BOD
95% of suspended solids
29% of nitrogen
35% of phosphorous
What does BOD stand for?
Biological oxygen demand
How much BOD, suspended solids, nitrgoen and phosphorous does the tertiary phase of waste water treatment remove?
100% of BOD
100% of suspended solids
33% of nitrogen
38% of phosphorous
What is the main attatched growth waste water treatment mechanism?
Trickling/ percolating filter
What are the main suspended growth processes?
- activated sludge processes
What is the main mechanism for wastewater treatment?
main process employed at major wastewater treatment plant
What are trickling/ precolating filters?
- very succesful wastewater treatment system
- microbial biofilm develops on carrier media (<0.1 - 0.3mm thickness)
- an aerobic microbial process
What is the degredation process in trickling/ percolating filters?
- extracellular enzymes (saprophytic)
- direct ingestion by metazoa and protozoa
- soluble inorganics and O2 difuse into biofilm
What does a trickling/ percolating filter consist of?
- circular or rectangular aggregate bed
- 5 - 10cm aggregate size
- 1.5- 2 m deep
- underdrain below aggregate
- settled sewage supplied through disruptor
- typical circular arrangement of 4 radial pipes
- moved by hyrdraulic flow or powered
What are the advantages of a trickling/ percolating filter?
- Simple operation
- low maintenance
- low energy use
- reliable
- sloughed biomass easily removed by sedimentation
- treat industrial wastewater
- buffered to withstand shock loadings (contaminants, excessive nutrients)
- biomass retained therefore not susceptible to wash-out
What are the disadvantages of trickling/ percolating filters?
- filter clogging due to microbial growth
- potential odours
- fly nuissance
- difficult to control
- poorer operations in cold conditions
- requires pretreatment and primary sedimentation
What is an activated sludge process?
- mixed culture of aerobic organisms to oxidise organic materials
- dynamic engineering system
- basic unit of activity is the FLOC
What is a floc?
a mass of essential bacteria associated with fungal filaments - forms a mesh structure
What is the process of activated sludge process?
- a mixed liquor of biomass and wastewater
- flocs consolidated by secondary sedimentation
- supernatant - discharge effluent
- recycel consolidation cells to aeration tank
- cell retention time > hydraulic retention time
- high microbial population achieves the max. rate of decomposition
- mixed suspension maintained by turbulence
What is the rapid stage of the activated sludge process?
- protperties of floc
- facilitate rapid absorption of soluble and colloidal molecules
- capture or particulate solide matter
- massively reduces the biological oxygen demand
What is the oxidation stage of the activated sludge process?
- Respiration at the intlet is increased as organic matter is oxideised
- rapid oxidation of readily degradable organics
- slower oxidation of recacritrant components
- respiration <0.01 intital rate at end of tank
What are the advantages of suspended growth systems?
- increased process control
- flexible as different redoc environments created by digester design
- reduced odour and fly problems
- smaller footprint then attatched growth systems
What are the disadvanages of suspended growth systems?
- susceptible to shock loads and contaminants
- susceptible to biomass washout
- more complex than trickling/ perolation methods
- susceptible to poor sedimentation
- high energy demand
What gas does anerobic digestion generate?
CH4 - methane
How much of the sewage sluge produces in the UK is treated by anerobic digestion?
70%
How much of the sewage sludge produce in the UK is applied as a fertiliser etc.
> 80%
What are the advantages of sewage sludge treatment?
- increases stability of biodgradable matter
- reduces odour and offensiveness
- reduces vector attraction (flies, rodents)
- reduces pathogen content
- improves physical properties for land application
What is the primary stage of sewage sludge treatment?
- pasteurization at 57 C for 5 hrs or 70C for 50 min
What is the secondary stage of sewage sludge treatment?
- sludge is dewatered and some liquid digestion may take place
- there is not heating or mixing
- residual gas is captured
- pathogen removal
- increase the sludge consolidation
- mechanically dewatered
What are the main biochemical processes that occur in anerobic decomposition?
- hydrolysis
- fermentation
- acetogeneisis
- methanogenesis
What is composting?
- an autothermophillic aerobic decomposition
- produces stackable solid substrates
- consists of sewage sludge, MSW, green waste
- degredation occurs over several weeks by microbial succession
- heat is generated by mesophillic activity conserved in heaps and increases temperatrure
- produces stabilised, dark brown residue
How long does the 4 stages of mivrobial succession take in composting?
- Mesophilic, thermophilic, cooling, maturation/ curing - 14-21 days
- maturation/ cooling >2-3 months
What happens during composting?
- mesophiles mutliply
- as the process nears 40 C the mesophilic activity declines and thermophillic funge take over
- the control strategy maintains a temperature between 40 and 60 C
- as >60C beneficial microbes are killed
What is the process of cooling/ maturation?
- Reacion rate slows as easily degradable substrates run out
- heat loss > heat generation
- bacterial and fungal biomas support succseion of higher organisms
- slow hydrolysis and assilimilation of complex polymeric substances by extracellular enzymes
- complex secondary reactions produce stable humified end-product
