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The settling out of suspended particles from water
What are the 3 steps to clarification?
- 1. Coagulation
- 2. Flocculation
- 3. Sedimentation
Define coagulation and give an example of something used for this in water treatment
- Bringing small particles together by neutralizing surface charges
- ex: Alum
Define flocculation and give an example of something used for this in water treatment
- Brings coagulated particles together by forming a polymer bridge
- ex: DrewFloc
The settling of the floc blanket to the bottom of the clarifying tank
Name 3 analytical techniques for detecting/analyzing TSS
- -PSA (Particle Size Analyzer)
- -SDI (Salt Density Index)
How is Stoke's Law used to improve separation of suspended material from water?
- Stoke's Law: Vt= (Pdisp-Pcont) x d2x g/18u
- -increase particle diameter (coagulants and flocculants)
- -increase density of dispersive phase/decrease density of continuous phase
- -increase g by using a centrifuge/cyclone
In which zone does flocculation occur?
Slow mix zone
Define depth filtration
- Trickling through a filter bed by gravity (torturous path)
- ex: Water running through soil
Define surface filtration
- Filtered through a thin, porous membrane
- ex: gravity filtration with filter paper
List five problems associated with having TSS in water
- 1. Aesthetically displeasing
- 2. Needs to be disinfected
- 3. Can corrode
- 4. Can cause eutrophication
- 5. Difficult to filter
How do inclined plates improve settling rates?
They decrease the distance the particles have to fall
Would a slow or fast flow rate be better for settling out particles
Slow - decreased horizontal distance the particle will travel
What's the difference between a centrifuge and a cyclone?
- -Cyclones have no moving parts
- -Cyclones have a smaller range of particle sizes they can remove (8um-800um vs. 1 um-800um)
Define produced water
Water that has come in contact with oil during petroleum production
Define slop oil
Oil contaminated with water that's been recovered from produced water
Name 3 ways to analyze for immiscible oil content in water
- 1. Use a centrifuge to determine ratio of oil to aqueous
- 2. BS&W
- 3. Solvent extraction methods
What does FWKO stand for and where is it used?
Free Water Knock Out; used just before the de-oiling process
What is the difference between adhesion and cohesion?
Adhesion is the attraction of liquid molecules to the solid surface, whereas cohesion is the attraction of liquid molecules to themselves
What does ORF stand for?
Oil Removal Filter
What are the two different types of emulsions that could occur in the petroleum industry?
- 1. Reverse - oil in water emulsion (O/W)
- 2. Normal - water in oil emulsion (W/O)
Name 4 ways to speed up separation of oil from water
- 1. Separation (ex: centrifuge)
- 2. Coalescence (ex: sorbants)
- 3. Filtration (ex: ceramic membranes)
- 4. Chemical treatment (ex: demulsifying agents)
What is coalescence?
The bringing of individual particles together to form a bigger mass
What does SAGD stand for?
Steam-Assisted Gravity Drainage
Name 2 methods of removing dissolved organics from water
- 1. Separation (adsorption, exclusion, stripping, extraction)
- 2. Destruction (CHEMOX, BIOX, bioreduction)
What is adsorption, and what is an example of adsorption used in industry?
- The sticking of gas molecules to a solid surface
- ex: GAC (granular activated carbon), PAC (powder activated carbon)
What does stripping do?
Removes low M.W. VOCs
What are some sources of TSS?
- -Natural source waters
- -Industrial waters
Are all hydrophobic molecules lipophilic?
Not necessarily (e.g.silicones and fluorocarbons are hydrophobic, but not lipophilic)
On-line Water Determination (the official term for a water-cut meter)
For separating oil droplets from water using adhesion, use a ____ surface
oleophilic (that way the oil will stick to the surface)
Name 4 types of TSO removal systems that rely on the concept of coalescence
- Dissolved Air Flotation (DAF)
- Induced Gas Flotation (IGF)
- Nutshell Coalescing filters
What's the difference between IGF and DAF?
IGF uses methane instead of air (less risk of explosion for IGF)
Which is more typical for removing oil from water - cross flow or through flow filtration?
Cross flow is more typical