Monitoring of activated sludge plant streams

ABSTRACT
This study investigated the possibility of controlling an activated
sludge plant by using continuous dissolved dry solids (DDS)
measurements and conductivity analysers. In addition, the correlations
of the results attained were compared to typical wastewater sum
parameters, such as COD or TOC. The tests were performed by
installing five (5) refractometers and five (5) conductivity analysers
in a wastewater treatment plant (WWTP) and by collecting data and
hand samples from a Finnish integrated pulp and paper mill. The
results indicate that new precision refractometers can be used in a
WWTP for the detection of very small changes in the DDS at low
concentrations (about 50 mg/L). The results also indicate a strong
correlation between the measured DDS and the COD and TOC values,
suggesting great potential for their use in monitoring influent load
and the quality of effluent before it is introduced into the local water
system. Conductivity measurement also works well, but since the
purpose of an activated sludge plant is to remove organic material
from wastewater, this measurement method is not very effective in
monitoring effluent load in the local water system. However, more
research is needed to gain a better understanding of the use of these
on-line measurements in monitoring the operation of WWTPs.

References: O PAPEL vol. 74, num. 9, pp. 61 - 65 SEP 2013

Authors*: Riku Kopra 1,2
Sakari Toivakainen 2
Pentti Tolonen 3
Tapio Tirri 1
Olli Dahl 2

* Authors references:
1. Mikkeli University of Applied Sciences, Fiberlaboratory, Vipusenkatu 10, FI-57200 Savonlinna, Finland.
2. Aalto University, School of Chemical Technology, P.O. Box 16300, 00076 Aalto, Finland
3. Stora Enso Fine Paper Veitsiluoto Mill, P.O. Box, 309, FI-94800 Kemi, Finland
Corresponding author: Riku Kopra, Mikkeli University of Applied Sciences, Fiberlaboratory, Vipusenkatu 10, FI-57200 Savonlinna, Finland – E-mail: riku.kopra@mamk.fi