A. Pollice et al., Monitoring the inhibitory effect of NaCl on anaerobic wastewater treatmentprocesses by the Rantox biosensor, ENV TECHNOL, 21(5), 2000, pp. 535-544
The Rantox biosensor, designed for anaerobic process control and based on t
he response of acetoclastic methanogenic microorganisms to periodic organic
overloads, was tested under variable operating conditions at laboratory sc
ale. The aim was to detect the presence of an incoming inorganic toxic comp
ound before any effect was observed in a digester under control. The experi
mental set-up, including the biosensor and the digester, was connected to a
n automated control system developed under a Labview(R) environment (the Ra
nter Virtual Instrument), and various operating conditions were tested in o
rder to interface the plant with the software properly. Anaerobic sludges w
ith different activities were used as active biomass in both reactors, and
inhibition was simulated by different NaCl dosing procedures. The results c
onfirmed the sensitivity and rapid response of the biosensor to unexpected
inhibitors in the feed, and demonstrated the suitability of this instrument
for continuous or semicontinuous monitoring of the influent to a digester
in order to prevent intoxication of its biomass. Furthermore, inhibition du
e to NaCl was found to be independent of the salt addition procedure. A con
centration of 15 g NaCl l(react)(-1) caused a decrease in peak biogas produ
ction ranging between 26.6% and 43.1%, depending on the different biomass t
ested.