The Moos KSA-system and the polymers used for ... - Simon Moos A/S

Cationic polymers
The cationic polymers are molecules with a positive charge and will react with sludgeparticles
with a negative charge. A cationic polymer must therefore be applied to a sludge type with a
negative charge - typically sludge from septic tanks, and from mechanical and biological sewagetreatment
plants.
Cationic polymers are co-polymers of acrylamide with increasing amount of cationic comonomeres.
The polymer is obtainable both as granulate and as emulsion. /9/
2.2 Heavy metals
Research has both shown certain heavy metals in polyelectrolytes and found the contents
negligible. The adding of heavy metals to the sludge through the polyelectorlytes is insignificant.
/2//3/.
Research has shown that the contents of heavy metals in the reject water often are below the limit
of detection. The very low contents of heavy metals in the reject water is a.o. due to:
- the very low contents in the polymer
- strong adsorption from the polymer
- formation of complexes of colloid particles during the
dewatering /10/
- the construction of the dewatering tank gives the sludge
filtrating characteristics
2.3 Non-environmental substances
The contribution to the contents of non-environmental organic substances in the sludge are
insignificant /2/
On this basis it is likely that there are no substantial environmental problems involved when the
products in question are applied in sludge dewatering /2/
A unique definition of the non-environmental organic substances is difficult, but seen in the light
of a similar American list with 192 substances, Sweden and Norway have made a list of priority
pollutants, comprising 70 non-environmental substances /4/.
Priority pollutants have been selected both because of their dangerousness to the environment
(toxicity, degradability and bio accumulation) and from the high frequency in use and occurence
/4/.
With a dosing of polymer at an average of 2,5 g/kg dry solids the polymer will give 0,045 Fg
chlorobenzenes/kg dry solids sludge and 0,625 Fg trichlorethane/kg dry solids sludge.