Ji. Lombrana et al., BIOKINETIC BEHAVIOR AND SETTLING CHARACTERISTICS IN AN ACTIVATED-SLUDGE UNDER THE EFFECT OF TOXIC NI(II) INFLUENCES, Water, air and soil pollution, 69(1-2), 1993, pp. 57-68
The inhibitory effect of Ni upon a biological system of activated slud
ge has been analyzed in two semicontinuous sequential reactors feeding
synthetic wastewater. One of the reactors was used as control while i
n the other given amounts of NiSO4 were added to the influent to achie
ve a concentration of 30 ppm Ni(II). An analysis of the characteristic
biokinetic parameters has been made and the correspondence with the o
perating conditions stated. A series of O2 uptake tests were proposed
and the results analyzed together with the specific rate of substrate
removal (U) in order to explain the toxic influence of Ni(II). An accu
mulation of undigested substrate on the flocs seems to explain certain
aspects derived of the presence of Ni. The sludge residence time (SRT
), within a certain range, can be used as a control operating variable
to mitigate the inhibitory effect of Ni, since a somewhat contrary ef
fect upon the settling characteristics of the sludge must be also cons
idered.