The non-stop growing demand on fresh water to meet the booming population and its corresponding activities, such as domestic, industrial, and agricultural developments, necessitates finding means to preserve our natural water resources and find alternative sources than can still meet our different needs. Greywater is one of the most potential alternatives that can be reused in some water consuming activities such as toilet flushing, gardening, landscape irrigation, and for agricultural purposes instead of wasting the higher water quality of potable water from being used in non-potable water activities. The present research was undertaken to investigate the potential of electrocoagulation technique for the treatment of greywater. The investigation work has been divided into two main phases. Phase I included studying the effect of the electrocoagulation operating parameters, such as the electrode surface area to water volume ratio, current density and electrolysis time, on the removal of COD and turbidity from synthetic greywater using I-optimal design of response surface methodology by Design expert 12 software. The experimental results showed model adequacy and significance. The experimental work was done on laboratory scale and a batch mode of operation. Three optimum conditions were chosen based on COD removal efficiencies of < 50%, 50%, and >50%, while maintaining residual turbidity value of no greater than 5 NTU and minimizing power consumption. Accordingly, three optimum set of conditions were obtained: set no.1 (CD = 31.06 A/m2, S/V =12.6 m -1, and T = 40 min), set no. 2 (CD = 62.13 A/m2, S/V =12.6 m-1, and T = 35 min) and set no.3 (CD = 73 A/m2, S/V =16.083 m-1, T=45 min). These optimum conditions achieved COD removal percent of 42.5, 51.08, and 56.06, respectively. Turbidity removal was 84.84%, 88.46% and 89.4%, while the specific power consumed was 3.9, 10.06, and 22.95 kWh/m3 for the three sets respectively. In phase II, the obtained optimum conditions of phase I were examined on the removal of BOD5,COD, Turbidity, TSS and FC from the real greywater and compared with different codes and standards. Compared to phase I, higher removal efficiencies of COD and turbidity were obtained in the three optimum sets. 80.6, 82.25, and 84.02 % COD removal, and 95.5, 95.5, 98.08 % turbidity removal with power consumption of 5.49, 8.23 and 21.6 kWh/m3 in the three experimental setups, respectively. Furthermore, the removal of other pollutant indicators, i.e.BOD5, FC, and TSS, were also studied. BOD5 removal efficiencies were 82.96%, 86.75%, and 87.88% in three experiments respectively. Also, FC were reduced by 99.65%, 99.64%, and 99.96%. In addition, TSS was removed by 83.19%, 92.98%, and 94.73% in the three experiments respectively. The treatment cost for the three experimental setups was estimated to be 9.46, 15.05, 33.49 EGP/m3 and 1.13, 1.8, and 4.0 EGP/capita/day, including power and electrode consumption. Sludge characterization of the first experimental setup using EDS and SEM showed that O, Al, C were three prevailing elements with a percentage of 51.62%, 29.69%,and 14.74% respectively. It can be concluded that electrocoagulation is a promising technique that could be used as a standalone system for the treatment of real greywater. However, further analysis on the diseases causing bacteria content in the water might be required to be able to meet the concerned codes and standards for reuse in different applications.
School of Sciences and Engineering
Mechanical Engineering Department
MS in Mechanical Engineering
Committee Member 1
Committee Member 2
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Youssef, S. O.
(2020).Greywater treatment using electrocoagulation for possible reuse [Master's Thesis, the American University in Cairo]. AUC Knowledge Fountain.
Youssef, Sarah Omar. Greywater treatment using electrocoagulation for possible reuse. 2020. American University in Cairo, Master's Thesis. AUC Knowledge Fountain.
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