Determination of inhibiting and toxic concentration of paper auxiliary agents

Inhibiting thresholds and toxic concentrations of paper auxiliary agents, used for the production of paper from paper stock, for anaerobic bacteria were determined. The total volume of methane produced was observed over at least a six-h period, and in many cases for up to 30 h. The time factor and the type of pretreatment were taken into account. The six groups of auxiliary agents studied were, in increasing order of inhibition, anti-foaming agents, sizing agents, retention agents, wet-strength agents, slimicides and cleaners.