AQUATIC CHEM QUIZ 3 Flashcards
What key processes do micro organisms carry out in water chemistry?
Photosynthesis and respiration
What are organic hazardous substances carried through water as?
As emulsions of very small particles suspended in water
Some hazardous materials are deposited in sediments
Autotrophic
Use solar/chemical energy to fix elements from simple non-living inorganic material—>complex life molecules that compose living organisms
PRODUCERS
Heterotrophic
Use organic substances produced by autotrophs as energy sources & as a raw material for the synthesis of their own biomass
Cannot produce its own food
DECOMPOSERS(bacteria, fungi)
The roles of micro organisms in water
- Oxygen production
- breakdown of biomass
- Catalysts of aquatic chemical reactions

Examples of microorganisms in water
- Algae
- fungi
- bacteria
Aerobic
Require molecular oxygen as an electron receptor
Facultative bacteria 
Uses free oxygen and other substances as electron receptors
Ways other than photosynthesis and respiration that microbes are involved in the C cycle
- Degradation of biomass
- Methane production
- Degradation of hydrocarbons
What is Nitrogen fixation
Any natural/ industrial process that causes free nitrogen
What is nitrification?
Reduced nitrogen compounds are oxidised to nitrite & nitrate
The conversion of N(-III) to N(V)
2O2 + NH4+ —> NO3- + 2H+ + H2O
What is Nitrate reduction?
Nitrate used as an electron acceptor in anaerobic conditions
2NO3- + {CH2O} —> 2NO2- + H2O + CO2
What is Denitrification?
A process I converts nitrate to nitrogen gas
End product- N2
What are the four trophic classifications of lakes?
- Oligotrophic - little to no aquatic vegetation
- Mesotrophic- intermediate productivity
- Eutrophic- large quantities of organisms (algal blooms)
- Hypereutrophic- excessive algal growth
OMEH
Liebig’s Law of the Minimum states: 
If one of the essential plant nutrient is deficient, plant growth will be poor even when all other essential nutrients are present
or
The yield of a given species should be limited by the nutrient that was present in the least quantity in the environment relative to its demand for growth
What are the Key variables for eutrophication?
Sunlight
Nitrogen
Phosphorus
TN stands for
TP stands for
Total nitrogen
Total phosphorus
Chl a stands for
SD stands for
Chlorophyll a
Secchi disk transparency
Factors that can influence eutrophication
Dissolved oxygen
Light
Macronutrients (Ca, Mg, K)
Salinity
What is eutrophication?
An enrichment of water by nutrients that cause structural changes to the ecosystem
E.g excessive growth of algae
Depletion of fish species
Deterioration of water quality
What does OECD stand for?
Organisation for economic cooperation and development
Affects cultural eutrophication is having on water bodies
Cultural eutrophication is caused by humans speeding up the process of natural eutrophication
Causing an abundance of particular substances, e.g. phytoplankton, bacteria, fungi & debris which determines the turbidity of water.
Low biodiversity
Depletion of fish
Low BOD levels
Signs of excessive eutrophication
Bad odour
Bad taste
Depletion of fish
Potentially toxic algae 
Cause of an excessive amount of nutrients
1.Fertilisers and agricultural run-off
2.Discharge of WASTE WATER

Nuisance Harmful Alage or Harmful Algal Blooms (HABS)
No toxins but high biomass
Toxic Harmful Alage or Harmful Algal Blooms (HABS)
Those that produced toxins or metabolites harmful to humans/ animals
What is a pesticide?
A substance for preventing or destroying pests
What techniques/steps are used in water treatment?
- Pre-treatment
- Mixing and coagulation
- Settlement
- Filtration
- Disinfection
Where is raw freshwater abstracted from?
Rivers, lakes and underground sources to be treated for human consumption
What are the objectives of water treatment?
safe for human consumption aesthetically appealing
reasonable cost
Public water supplies normally service the requirements of where
Domestic households
Industry
Commercial
What are the two sets of standards for water quality
- Quality of raw water
2. Quality of treated water
What are the four classes of water treatment?
Class A- no treatment
Class B- used for public supplies, disinfected
Class C- standard treatment, from lowland areas & reservoirs
Class D- when industries require high quality/ source is down stream of urban develpments
What processes occur in pre-treatment of water?
Screening Raw water storage Aeration Preliminary settling Prechlorination
SRAPP
Purpose of screening and water treatment
To remove large floating debris and suspended solids (leaves, twigs, plastics) 
What three types of screens are used for screening
Bar screens
Band and drum screens
Micro strainers
What is raw water storage?
Practical temporary storage
Water usually needs to be stored before treatment
Usually stored in reservoirs
Benefits of raw water storage
- Natural settlement occurs
- Reduction in number of pathogenic bacteria
- Water quality improves with storage especially relating to suspended solids
Benefits of aeration 
- Improves raw water quality
- Supplies oxygen
- Liberates unwanted gases e.g. CO2
- Cheap process
What is Chlorination 
And essential method of disinfection
LAST STAGE of treatment
What is prechlorination
Injecting chlorine into raw water straight after abstraction from river
Used on water with HIGH BACTERIAL COUNT
Why is chlorination still necessary after prechlorination?
Organic matter reacts with chlorine at this stage reducing its effectiveness as a disinfectant
Negatives of prechloriantion?
High amount of chlorine needed, moreso than later stage chlorination
Example of a coagulant
Ferric chloride
Purpose of filtration
To remove fine non-settleable particles from water
Name three types of filtration
- Slow sound filtration
- Rapid sand filtration
- Activated carbon
Deficiency affiliation depends on
- The size and shape of the media
2. Rate flow of water through the filter
Limitations of Chlorination 
Chlorination byproducts- potential long term effects
taste and odour issues can affect quality 
Lower effectiveness in TURBID WATERS
Example of chlorination by product
Trihalomethanes
What type of water is prechlorination generally used on?
Water with high bacterial count
