BUDAPEST UNIVERSITY OF TECHNOLOGY AND ECONOMICS
FACULTY OF CHEMICAL AND
BIOCHEMICAL ENGINEERING
DEPARTMENT OF CHEMICAL AND
ENVIRONMENTAL PROCESS
ENGINEERING
DETERGENT
CONTAINING WASTEWATERS
Dr. Bajnóczy Gábor
Tonkó Csilla
SURFACE ACTIVE CHEMICAL AGENT CONTAINING WASTEWATERS
Surface active chemical agent:
dissolved or dispersed in fluid (water),
tending to adsorb on the surface of fluid
changing the physical-chemical
properties of the fluid surface.
surface-active chemical agent
detergent:
organic synthetic cleaning agent
soap:
sodium and potassium salt of saturated
or unsaturated long carbon-chain
carboxylic acid
detergent
soap
SURFACE ACTIVE CHEMICAL AGENT,
SOURCES DETERGENT POLLUTION
NATURAL:
Algae bloom: significant surface
active compound → foaming
HUMAN:
Cleaning activities
COMPONENTS OF DETERGENTS AND
ENVIRONMENTAL ASPECTS
1. Surface active compounds
a./ Anionic detergent: on straight carbon chain R1–COO– (carboxylate),
R2–SO3– (sulphonate) and R3–SO4– (sulphate) groups,
used in washing machines.
Carbon-chain can’t be branched, carboxylates are especially fast biodegradable.
Non-toxic, but high oxygen demanding materials in natural waters.
b./ Cationic detergent: end of chain kvaterner ammonium group R-NH3+,
antiseptic effect, used as rinsing material.
Using is forbidden in washing powders: kills the micro organisms in technology
of sewage water treatment.
c./ Non-ionic detergent: the straight carbon-chain molecule contains partial
negative charged alcoholic group or ether bond.
Fine detergents, body wash.
Carbon-chain can’t be branched, due to alcoholic group fast biodegradable.
Non-toxic, but high oxygen demanding materials in natural waters.
2. Addidives to reduce water hardness
Water hardness: caused by water dissolved calcium
and magnesium salts of water.
in soft water
R – SO3-
in hard water
R – SO3-
Na+
R – SO3
Ca++
R – SO3-
the non-polar and polar
part remains active
Ca
R – SO3
the non-polar and polar
part cease, no washing effect
a./ Old type water hardness reduction: trisodium - phosphate
2 Na3PO4 + 3 Ca 2+ = Ca3(PO4)2 + 3 Na+
precipitate
Can not be applied in washing machines.
b./ water-solube, complex forming, water hardness reducing additives
(phosphorus-containing)
Ca 2+
Na3P3O10
+
Mg 2+
large stability constant,
water soluble,
Ca or Mg complex
- non-toxic
- non-corrosive
- non-flammable
- known substance
- easy biodegradable
- hydrolyzing on known compounds in water
P3O10 5+ + 2 H2O = 2 HPO42- + H2PO4-
Significant phosphorus load in natural water
+ Na +
b./ water-solube, complex forming, water hardness reducing additives
(phosphorus free)
POLYCARBOXYLATES
H2C = C – C = O
H
acrylic acid
Maverage = 2 000 – 10 000
CO2Na
sodium-polyacrylate
n
CO2Na
H2C = C – C = O + O = C – C = C – C = O
H
H
H
acrylic acid
maleic acid
NaO2C
CO2Na
n
sodium (acrylic acid -maleic) copolymer
Mátlag = 20 000 – 70 000
polycarboxylates with Ca++ and Mg++ ions: form stable and water-soluble complex
Composition of phosphate containing and phosphate free
washing powder [%]
P base
sodium-tripolyphosphate
zeolite
P free
20 – 25
0
0
25
also in P-free, because zeolite is slow and
replaces only calcium ion to sodium
polycarboxylates
0
organic phosphonates
0 – 0,2
sodium silicate
6
4
sodium carbonate
5
15
surface active agent
12
15
sodium perborate
14
18
2
2,5
activator
sodium sulphate
5
1 – 24
0,4
corrosion inhibitor additive
alkaline, more in P-free
more in P-free, because sodium-tripolyphosphate
helps better the washing effect than
carboxylates
disinfectant
9
enzymes
1
sedimentation inhibitor
0,2
1
optical whitener
0,2
0,2
odorant
Ion-exchange mineral: instead of expensive polycarboxylate,
makes the textile greyish, increases wastewater sludge
0,5
varied
activator of desinfectant T < 60 °C
due to zeolite more in P-free
DEGRADABILITY OF POLYCARBOXILATES
Polycarboxylates: long chain -> hardly biodegradable.
Shorter carbon-chain fractions: relatively fast degradation (8 – 15%).
In spite of good water-solubility and long lifetime, the bioaccumulation hasn’t risk,
because the large molecular compound can’t penetrate through the cell membrane.
90 – 95% removal efficiency can be achieved by wastewater treatment which
Is due to the strong adsorption tendency on sludge.
No enter into the natural water, no risk of heavy metal extraction from the mud.