DEVELOPMENT OF A TREATMENT SYSTEM FOR ANTIBIOTIC WASTEWATER

Antibiotics are emerging contaminants in the aquatic environment because of their
adverse effects on aquatic life and humans. The problem that may be created by the
presence of antibiotics at low concentration in the environment is the development of
antibiotic resistant bacteria. Antibiotic sources in the environment are antibiotic
industry, human excretion and excretion form livestock. No work has been reported
on complete treatment of antibiotic wastewater containing amoxicillin, ampicillin and
cloxacillin. The overall objective of this work was development of an effective
treatment system for antibiotic wastewater from an antibiotic industry producing these
antibiotics. The work was conducted in three phases.
In Phase I, four advanced oxidation processes (AOPs) (Fenton, photo-Fenton,
UV/Ti02 and UV/ZnO) were applied for treatment of amoxicillin, ampicillin and
cloxacillin antibiotics in aqueous solution. From a technical point of view, Fenton,
photo-Fenton and UV /H202/Ti02 processes were able to degrade the antibiotics and
tmprove biodegradability; however, UV/ZnO process did not improve
biodegradability. Based on DOC removal, the photo-Fenton process exhibited the
highest rate constant (0.029 min- 1
) followed by the Fenton (0.0144 min- 1
), UV/ZnO
(0.00056 min-1
) and UV /H20 2/Ti02 (0.0005 min- 1
). From an economic point of view,
the photo-Fenton process appeared to be the most cost-effective compared to the other
studied processes. In Phase II, the feasibility of using three combined AOP and
sequencmg batch reactor (SBR) (Fenton-SBR, photo-Fenton-SBR and
UV /H20 2/Ti02-SBR) for complete treatment of an antibiotic wastewater from a local
antibiotic industry producing amoxicillin, ampicillin and cloxacillin, was evaluated.
Combined systems were operated for several months to study the effect of AOP and
SBR operating conditions on the combined system performance. From a technical
point of view, both combined Fenton-SBR and photo-Fenton-SBR systems achieved
an overall efficiency of 89% for sCOD removal and the final effluent met the
discharge standard. However, the combined UV/H20 2/Ti02-SBR system was not a
feasible combined system for treatment of the antibiotic wastewater. From an
economic point of view, the combined Fenton-SBR system appeared to be more cost-effective than the combined photo-Fenton-SBR system. The Monod kinetic model
was fitted to the results of biodegradation of the Fenton-treated effluent by SBR under
the best operating conditions with the kinetic constants kob 0.078 k 1
, Y XIS 0.60 and
K.i -0.0013 hr- 1
• The values of kob, Y x;s and Kd for biodegradation of the photoFenton-
treated effluent under the best operating conditions were similar to those of
Fenton-treated effluent. In Phase Ill, artificial neural network (ANN) was applied for
modelling, simulation and prediction of the Fenton process performance. ANN
predicted results were very close to the experimental results with correlation
coefficient of 0.997 and mean square error of 0.000376. The sensitivity analysis
showed that all studied variables have strong effect on COD removal and H20 2/Fe2+
molar ratio is the most influential parameter. The study showed that neural network
modelling could effectively predict and simulate the behaviour of the Fenton process.
The study culminated in development of an effective treatment systems for antibiotic
wastewater. From technical and economic point of view, combined Fenton-SBR
system was the most effective for treatment of the antibiotic wastewater.