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.

detergent: organic synthetic cleaning agent soap: sodium and potassium salt of saturated or unsaturated long carbon-chain carboxylic acid surface-active chemical agent 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 R 1 –COO – R 2 –SO 3 – (sulphonate) and R 3 (carboxylate), –SO 4 – (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-NH 3 + , 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 in hard water R – SO 3 Na + the non-polar and polar part remains active R – SO 3 R – SO 3 Ca ++ R – SO 3 Ca R – SO 3 the non-polar and polar part cease, no washing effect a./ Old type water hardness reduction: trisodium - phosphate 2 Na 3 PO 4 + 3 Ca 2+ = Ca 3 (PO 4 ) 2 precipitate + 3 Na + Can not be applied in washing machines.

b./ water-solube, complex forming, water hardness reducing additives ( phosphorus-containing ) Na 3 P 3 O 10 + Ca 2+ Mg 2+ large stability constant, water soluble, Ca or Mg complex + Na + - non-toxic

-

non-corrosive

-

non-flammable

-

known substance

-

easy biodegradable

-

hydrolyzing on known compounds in water P 3 O 10 5+ + 2 H 2 O = 2 HPO 4 2 + H 2 PO 4 Significant phosphorus load in natural water

b./ water-solube, complex forming, water hardness reducing additives ( phosphorus free ) POLYCARBOXYLATES H 2 C = C – C = O H acrylic acid CO 2 Na sodium-polyacrylate n M average = 2 000 – 10 000 CO 2 Na H 2 C = C – C = O H acrylic acid + O = C C = C – C = O H H maleic acid NaO 2 C CO 2 Na n sodium (acrylic acid -maleic) copolymer M átlag = 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 P free sodium-tripolyphosphate 20 – 25 0 zeolite 0 25 polycarboxylates 0 5 organic phosphonates 0 – 0,2 0,4 sodium silicate 6 4 sodium carbonate 5 15 surface active agent 12 15 sodium perborate 14 18 activator 2 2,5 sodium sulphate 1 – 24 9 enzymes 1 0,5 sedimentation inhibitor 0,2 1 optical whitener 0,2 0,2 odorant varied

Ion-exchange mineral: instead of expensive polycarboxylate, makes the textile greyish, increases wastewater sludge also in P-free, because zeolite is slow and replaces only calcium ion to sodium corrosion inhibitor additive alkaline, more in P-free more in P-free, because sodium-tripolyphosphate helps better the washing effect than carboxylates disinfectant 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.