Abstract Microorganisms, organic matter, heavy metals
are the main pollutants in sewage water. The increasing
water demand pressurized people to use the sewage water.
Different systems, chemicals and physical treatments were
used in sewage water treatment. The aim of this work is to
study the effect and correlations of primary (Ca(OH)2 filtration
and H2O2) and secondary (dissolved oxygen,
organic matter, conductivity, pH and OD) factors on fungi
present in sewage water in addition to proving the sequence
of the system used in the current study. After treatment,
fungi were examined, identified on Czapek agar and analyzed
using multivariate tools (CANOCO: DCA and CCA)
and R software. The treatment includes two main steps:
liming filtration and oxidation, respectively. All parameters
were negatively or positively correlated (organic matter,
pH, conductivity %, optical density, fungal CFU ml-1,
dissolved oxygen). Heavy metals were decreased due to the
application of Ca(OH)2 and H2O2, respectively. There were
two main groups of fungi. The larger was correlated with
the organic matter, whereas the second was tolerating
calcium hydroxide concentrations. Aspergillus sydowii
tolerated hydrogen peroxide (0.2 mll-1(33%); Ca(OH)2,
0.25 gl-1). Sequential steps treatment was healthy and
economically efficient. The proposed system improved
water characteristics. The recommended amount of
Ca(OH)2 and H2O2 was 0.25 gl-1 and 0.2 mll-1(33%),
respectively, and can remove more than 99.9% of fungal
CFUs. The current study minimized the optimum dose of
hydrogen peroxide used in the disinfection of sewage water
from 1.5 (Mohamed in Chem Eng J 119:161–165, 2006) to
0.2 mll-1 of H2O2 (the current study).