Liquid Pollution Control Flashcards
state some advantages of membrane technology?
low energy consumption
scale up is easy
batch and continuous separation is possible
state some disadvantages of membrane technology
risk of fouling
short membrane lifetime
low selectivity
List 4 pressure driven membrane technologies in order of separation size range
microfiltration, ultrafiltration, nanofiltration, reverse osmosis
state assumptions when modelling for RO
assuming no cake build up
solid particles are mostly removed in upstream separation
P overcomes osmotic pressure and membrane resistance
Draw diagram showing NEWater Treatment Process
What is NEWwater?
A process designed to create potable from raw water
Define coagulation
consolidate suspended contaminants for easy removal by adding a coagulant that will form a precipitate
Define flocculation
remove suspended solids from wastewater by aggregating contaminants into flocs.
Name three mechanisms of flocculation
patch floccuation, bridging, charge neutralisation
what is an indifferent electrolyte
an electrolyte containing chemical species that are not electroactive
What are low MW polymers best suited towards
vacuum and pressure filtration
What are higher MW polymers best suited towards
best suited to belt filtration, sedimentation and centrifugation
What is an electro double layer?
a layer that forms on the surface of an object when exposed to a fluid. The first layer is the surface charge which ions adsorbed onto the surface
what is electrocoagulation?
electrocoagulation is when an electric current is sent through dirty liquid to allow for agglomeration of particles
what is the benefit of electrocoagulation
it is cheaper than chemical coagulation
