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CPE408 Liquid Effluents > Sampling and Characterisation > Flashcards

Sampling and Characterisation Flashcards

1
Q

Why do the constituents of wastewater and liquid effluents need to be characterised?

A
  1. To know what possible effects industrial liquid effluents could have on the environment
  2. To know what treatment processes are required
  3. To achieve legislative discharge constraints (permits)
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2
Q

Why do people try and do measurements in situ rather than in a lab?

A

So the chemistry does not change

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3
Q

What 4 things should be considered when deciding on a sampling location?

A
  1. The sample must representative of the whole of that material
  2. Location specified in the original permit
  3. The sample should be drawn from an area in which flow is homogenous
  4. That care can be taken to avoid creating excessive turbulence to avoid the liberation of dissolves gases which would yield an unrepresentative sample
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4
Q

How do you decide how frequently to sample?

A

By assessing the degree of flowrate variation, which must be short enough to provide a true representation of the flow

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5
Q

What recommended sampling interval allows estimation of the average concentration during the sampling period, and why might this not be the case?

A

10-15 min

Depending on the industry it may be undesirable to average data

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6
Q

What are the two main sampling techniques?

A

Grab sampling - a technician will take a sample a particular time and place
Composite sampling - a technician will take the sample at the same point but a different time of day each time

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7
Q

What is the advantage of grab sampling?

A

Reduced sampling frequency if the source is stable in composition over a series of time

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8
Q

How would you decide which sampling technique to use?

A

By sampling as many points and times as possible to see what kind of variation there is

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9
Q

What are the disadvantages of grab sampling?

A
  • variation with time means increased sampling freq. + cost

- variation with space means samples must me collected from multiple locations

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10
Q

What are the advantages of composite sampling?

A
  • cheaper

- samples are representative of the entire shift/production sample

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11
Q

What are the disadvantages of composite sampling?

A
  • can only be used for determining the components that can be demonstrated to remain unchaged under the conditions of sample collecion and preservation
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12
Q

How can wastewater flow values change?

A

Concentration and amount may vary significantly over the course of any day/year

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13
Q

What are the three main types of characteristics of wastewater?

A
  1. Physical
  2. Chemical
  3. Biological
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14
Q

Give 5 physical properties of wastewater

A
  1. Solids
  2. Turbidity
  3. Colour
  4. Odour
  5. Density
    - ————————
  6. Temperature
  7. Particle size
  8. Transmittance
  9. Conductivity
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15
Q

Give 5 chemical properties of wastewater

A
  1. Nutrients
  2. Heavy metals
  3. pH (very related to acid mine drainage)
  4. Hormones
  5. Salts
  6. Fats, oils and greases
  7. Emerging (pharma etc.)
  8. Organics
  9. Sulphates
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16
Q

Give 5 biological properties of wastewater

A
  1. Bacteria
  2. Fungi
  3. Algae
  4. Rotifers (slightly larger and eat algae)
  5. Yeast
  6. Viruses
  7. Archae
  8. Protozoa
    (all but 4 and 8 are examples of microorganisms)
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17
Q

List 7 physical and chemical detection methods from cheapest to most expensive

A
  1. Visual
  2. Colorimetric
  3. Titrimetric
  4. Specific electrodes
  5. Ion chromatography
  6. HPLC (high-performance liquid chromatography)
  7. GCMS (gas chromatography-mass spectrometry)
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18
Q

Why are some detection methods more expensive than others?

A

They are made from more advanced technology, they take more time to develop and use, and you will need special training in order to use themm

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19
Q

How much of domestic wastewater is solids?

A

About 0.1%

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20
Q

How much of solids in domestic wastewater is organic/inorganic?

A

Organic 70% (protein 65%, carbs 25% and fats 10%)

Inorganic 30% (grit, metals, salts)

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21
Q

What 4 categories can solids in wastewater be put into?

A
  1. Floating matter
  2. Settleable matter
  3. Colloidal matter
  4. Matter in solution
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22
Q

What does TS stand for?

A

Total solids

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23
Q

What does TSS stand for?

A

Total suspended solids

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24
Q

What does TDS stand for?

A

Total dissolved solids

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25
Q

What does FSS stand for?

A

Fixed suspended solids

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26
Q

What does VSS stand for?

A

Volatile suspended solids

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27
Q

What does VDS stand for?

A

Volatile dissolved solids

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28
Q

What does FDS stand for?

A

Fixed dissolved solids

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29
Q

What does TVS stand for?

A

Total volatile solids

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30
Q

What does TFS stand for?

A

Total fixed solids

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31
Q

How do you measure settleable solids?

A

Imhoff cone (1L) - solids that accumulate in the bottom of the cone after 30/60 min reported in mL/L

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32
Q

How do you measure total solids in 1 step?

A

Evaporation and dried at 103-105 deg C

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33
Q

How are TSS and TDS measured from a wastewater sample?

A

Firstly filtered through Whatman glass fiber (pore size 1.58um)
TSS - evaporation of filter retained solids at 105 deg C
TDS - evaporation of filtrate and dried at a specific T, consists of colloidal (0.001-1um) and dissolved solids

34
Q

How are VSS and FSS measured from a wastewater sample?

A

By igniting the total suspended solids in a muffle oven at 450-550 deg C (lost=V, remains=F)

35
Q

How are VDS and FDS measured from a wastewater sample?

A

By igniting the total dissolved solids in a muffle oven at 450-550 deg C

36
Q

How are TVS measured from TS?

A

Solids that are burned off when TS are ignited (450-550 deg C)

37
Q

How is TFS measured from TS?

A

Residue that remains after TS are ignited (450-550 deg c)

38
Q

What kinds of materials are settleable?

A

Grit, sand, metals

39
Q

How is turbidity of a wastewater measured?

A

A standard solution is made from adding Formazin, which is a polymer that doesn’t dissolve and impacts colour. The intensity of the light scattered through the sample is measured using a spectrophotometer and compared to the light scattered by a standard under the same conditions, then reported in nephelometric turbidity units

40
Q

How is colour of a wastewater sample measured?

A

Colour can be measured using turbidity or by comparison to a colour wheel.
pH is often measured at the same time as this can also change the colour depending on what is causing it

41
Q

What affects the colour of a wastewater material?

A

Dissolved organics, minerals or chemicals

42
Q

How does wastewater colour change with age?

A

The more aerobic the conditions, the more black the water will become over time

43
Q

What are the two types of fats, oils and greases?

A
  1. Non-polar FOG (petroleum or mineral origin) (most likely come from industry and need an oil/water separator)
  2. Polar FOG (animal/vegetable origin)
44
Q

What type of wastewater has the highest amount of fats, oils and greases?

A

Domestic (butter/lard/meats/seeds/soap)

45
Q

Where do FOGs make the most problems?

A

Causes problems in sewers and waste treatment plants due to their low solubility and they impact the rate of microbial degradation. They also cause unsightly floating matter and films, and block pipes

46
Q

How much is spent on sorting FOG blockages in sewers each year?

A

£15mil

47
Q

What problems can FOGs cause in wastewater treatment plants?

A

Can cause serious problems in pumps

48
Q

How are FOGs measured?

A

FOGs are extracted from water through the use of an appropriate solvent and extraction procedures.
The hydrocarbons absorb infrared energy at a specific wavelength and the amount of energy absorbed is proportional to the concentration of that oil and grease in the solvent.

49
Q

Name 5 toxic and hazardous substances in wastewater

A
  1. VOCs
  2. Surfactants
  3. Pesticides
  4. Heavy metals
  5. Chlorination byproducts
50
Q

Why are heavy metals in water a problem?

A

Some metals in small quantities are necessary for growth of biological life, but in larger persistent dosages can become toxic (bioaccumulation)

51
Q

What are the sources, forms, regulatory levels and toxic effects of Chromium?

A

Sources: tanneries, catalyst manufacture, pigments&paints, fungicides, ceramic/glass, photography chrome alloy/metal/plating production
Forms: Cr III, Cr VI
Regulatory levels: 0.05 mg/L
Toxic effects: acute gastrointestinal disorders, heamorrhagic diathesis, convulsions, death. Also increased genotoxic effects eg. DNA damage

52
Q

What are the sources, forms, regulatory levels and toxic effects of Zinc?

A

Sources: paints, white pigment in rubber, production of alloys and brass, pesticides, piping and fittings
Forms: Zinc oxide, zinc carbamates
Regulatory levels: no formal guideline
Toxic effects: acute toxicity, vomiting, muscle pains, fever, bleeding, heart disease

53
Q

What are the sources, forms, regulatory levels and toxic effects of Copper?

A

Sources: mining, pipes, fungicides, fertilisers, insecticides, wood preservatives, algae control
Forms: copper(I) oxide/ammonium/chloride, copper(II) ion common in water, CuCO3
Regulatory levels: 2 mg/L
Toxic effects: Short term, high doses cause internal bleeding, low doses similar to food poisoning - headache, vomiting, diarrhoea. Percuntaneous effects are prevalent especially through damaged skin.
Long term: liver damage/childhoos cirrhosis on sensitive people

54
Q

What are the sources, forms, regulatory levels and toxic effects of Cadmium?

A

Sources: anticorrosive plating on steel, pigments in plastics, batteries, fertilisers produced from phosphate ores
Forms: Pure form/ cadmium sulphide
Regulatory levels: 0.003 mh/L
Toxic effects: Long term: kidney damage (most important). Acute: skin and lung cancers (inhalation)

55
Q

What are the sources, forms, regulatory levels and toxic effects of Mercury?

A

Sources: chlorine and caustic soda, lamps, fungicides, antiseptics, preservatives, pharma, electrodes
Forms: mercury vapour, mercury(II) chloride, mercury(I) chloride, mercury sulphide, methyl mercury
Regulatory levels: 0.001 mg/L
Toxic effects: High doses: neuroligical/renal disturbances. Kidney damage, vomiting, diarrhoea, shock, salivary gland swelling, tooth loss, death, dermatitis
Long term: Effects on lungs, central nervous system, gastrointestinal tract and kidney, brain size, blurred vision and mental impairment for children at birth (cerebal-palsy like conditions), Minamata disease

56
Q

What are the two ways the heavy metals are usually measured?

A
  1. Atomic absorption spectroscopy - light can be absorbed by free metallic ions compared to a standard
  2. ICP-MS (more accurate), ionising the samples (high T) then through a mass spectrometer
57
Q

How do pharma products end up in wastewater and what affect does this have?

A

Not all of the drug is used by your body therefore produces metabolites that are excreted. These metabolites may have a more adverse effect on the environment than the parent drug.

58
Q

What is an example of an ‘emerging threat’?

A

Pharma and personal care products and hormones

59
Q

Where in the chain do we usually detect the effects of pharma in wastewater?

A

Used to be once it started affecting fish, but now can be detected at microbial level before it gets to that stage.

60
Q

What human activities are reflected in our wastewater?

A

The food we eat, materials we use in our home, what illnesses we have

61
Q

How are trace pharmaceuticals measured in wastewater?

A

HPCL-MS (high performance liquid chromatography - mass spectrometry) or HPLC-MS-MS which gives a more accurate reading. Ionises and then weighs the fraction of each ion.

62
Q

What is the ideal solution for pharma in wastewater?

A

To be able to characterise them and pull them out, treat and upgrade to be reused somehow

63
Q

What kind of gases do we see in untreated wastewater?

A

Nitrogen, oxygen, CO2, hydrogen sulphide, ammonia, methane

64
Q

What kind of gases do we see in wastewater as a result of the treatment process?

A

Chlorine, ozone (disinfection and odour control, oxides of sulphur and nitrogen (combustion)

65
Q

What are the characteristics of methane and why is methane found in wastewater?

A

Colourless, odourless, combustible hydrocarbon of high fuel value. Product of anaerobic decomposition of inorganic matter - not found in fresh wastewater due to the presence of lots of oxygen

66
Q

What are the characteristics of methane and why is methane found in wastewater?

A

Colourless, inflammable compound with the characteristic odour of rotten eggs. It causes wastewater to blacken when H2SO4 combines with iron to form FeS (ferrous). Formed from the anaerobic decomposition of organic matter containing sulphur

67
Q

What are the safety issues with methane and hydrogen sulphide and how can they be lessened?

A

Methane: explosion hazard
H2SO4: toxic
Issue where gases accumulate in process equipment (manholes/sewer junctions).
Use gas detectors and implement proper training.

68
Q

What are pathogens?

A

Specific organisms causing disease

69
Q

How do pathogens end up in wastewater?

A

They can live for a period of time outside the human body. They come from the intestinal tract and are excreted into wastewater and can be transmitted to anyone who contacts the water.

70
Q

What are the 5 sources of pathogens?

A
  1. Domestic greywater and blackwater
  2. Hospitals
  3. Schools
  4. Farms
  5. Food processing plants
71
Q

Give 4 examples of pathogens

A
  1. E. coli
  2. Salmonella
  3. Legionellosis
  4. Rotavirus
72
Q

In what other ways than drinking wastewater can pathogenic outbreaks occur via water?

A

Eating contaminated fish, recreational activities, animals/insects that come into contact with the water

73
Q

What is the advantage and disadvantage of cultivation measurement of pathogens?

A

Relatively inexpensive and low tech but time consuming (2-3 days)

74
Q

Name the two types of traditional cultivation measurement of pathogens

A
  1. Selective media: inhibits the growth of one group while allowing another to flourish eg. adding salts often kills ‘good bacteria’ but resistant bacteria will continue to grow
  2. Differential media: allows all organisms to grow but causes one group to appear different eg. turning a different colour (lactose fermenters turn pink)
75
Q

How do the CDC (centre for disease control) rapid tests work?

A

You put your microbes in a water sample and add a strip that already has chemicals on it, then compare to a colour chart to see if general families of pathogens appear.

76
Q

Describe the modern day molecular approach to measuring pathogens

A

Sequence a bit of DNA via PCR (polymerase chain reaction - denature, anneal, elongate) to make copies and match it to a database

77
Q

What is the advantage and disadvantage of modern measurement of pathogens?

A

Increased specificity, high tech, but need a trained technician and is expensive

78
Q

How is coliform measured in wastewater?

A

By the most probable number technique. Coliform is a rod-shaped gram-negative (cell wall type) bacteria that ferments lactose and produces acid and gas at 35-57 deg C. The wastewater is diluted into a solution that contains lactose (3 different dilutions, 10 mL, 1 mL, 0.1 mL), and incubated at 37 deg C for 24 hours and assessed for a colour change and bubbles.
The data

79
Q

What is a coliform test good for?

A

It may be the easiest way to see how effective your treatment process is.

80
Q

What is MPN and how is it calculate?

A

Using an MPN table/calculator to combine the positive results from each dilution

CPE408 Liquid Effluents (8 decks)

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