Thesis Archive
Treatment of Quick Service Restaurant Wastewater by Electrocoagulation (2011)
Chin, Jake Lawrie T.
Choa, Christopher Kenneth N.
Abstract:
– In this study, the applicability of an electrocoagulation (EC) reactor in the treatment of quick service restaurant (QSR) wastewater was investigated. The electrodes were composed of aluminium (Al) and iron (Fe) which were vertically-oriented in the EC reactor. The wastewater used for the study came from the wastewater discharges of a college canteen. The characteristics of the canteen’s wastewater were comparable to the characteristics of the wastewater discharges from quick service restaurants (QSR). The estimated wastewater discharge volume of QSR in the Philippines is about 200,000 cubic meters per day wherein the pollutant concentration of these wastewater are also in non-compliance with the effluent standards stated in the DENR Administrative Order 35 (DAO 35); therefore, investigating the wastewater treatability using compact wastewater treatment technology like EC is very important.
The wastewater source from the exiting end of grease trap of the canteen has the following characteristics: COD ranging from 300 to 7000 mg/L, TSS ranging from 200 to 1100 mg/L and BOD ranging from 100 to 120 mg/L. The initial pH of the solution was adjusted to pH 6 or pH 8 by HNO3/NaOH. The conductivity was increased by the addition of NaCl. The presence of chloride ions hastens the anode dissolution due to pitting corrosion. The experiments were conducted within 2 hours of continuous run employing four monopolar electrodes to determine the effects of various operational parameters such as initial pH and electrode configurations in the removal efficiency of the EC reactor. Furthermore, froths, sludge and electrodes were analyzed by scanning electron microscope (SEM) and energy dispersive x-ray (EDX).
Results showed that the electrodes were found to develop oxide film after the EC process. An increase in solution pH, and temperature and a decrease in conductivity, and DO were highly observed. BOD did not undergo change in its values with EC treatment method. Optimization of the important operating parameters such as initial pH, electrolysis time, and electrode configuration improved the overall treatment efficiencies on FOG by 58.09% and TSS by 68.19%. Optimum electrocoagulation conditions were established at pHo = 6, electrolysis time = 20 min, and with Al-Fe electrode configuration. The optimization was carried out by response surface methodology.
The treatability study showed that EC could be used as alternative treatment process for QSR wastewaters which requires compact and simple maintenance operations.
Adviser:
Josephine Q. Borja
Aileen Huelgas
Elaine G. Mission