Greywater Treatment Using Banana Peel Biochar and Sand Filtration

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Addis Ababa University


Sand has been used for long time to treat greywater. However, biochar might be an alternative to replace the sand for greywater treatment and also reduce the amount of organic waste disposed into the environment. In this study the biochar was produced from banana peel and the purpose was to evaluate and compare the performances of biochar, sand and sand with biochar in reducing turbidity, COD, N, P, fecal coliform and pH. The biochar and sand were packed to a depth of 27 cm into columns with a diameter of 7 cm but in case of sand with biochar the depth was 13.5 cm for sand and the remaining was filled by biochar. The columns were fed with synthetic and real greywater. Synthetic greywater was used for optimization of biochar particle size and pH. Real greywater was fed to the column by taking the optimum biochar particle size and pH and compared with, sand and sand with biochar for four days. Biochar was prepared in three different sizes: Fine, medium and coarse with a size of below 1mm, between 1-3 mm and above 3mm, respectively. Fine particle size of biochar showed more removal efficiency than medium and coarse sized particles. The average performance of fine medium and coarse particle size was 88%, 71.2% and 39.3% for turbidity 54.8%,36.5% and 23.1% for COD,62.2%, 23.4% and 12.6% for N and 52%,18.4% and 9.4% for P respectively. But in all particle sizes of biochar effluent pH and EC values were found to be more than that of the influent. For the optimization of pH values that varied from 5 to 10 were tested. The results of the analysis showed that the highest removals of turbidity (89%), COD (55%), N (94%) and P (78.8%) were achieved at pH value of 7. Fine biochar (FBC) showed better removal efficiency when compared to that of sand and biochar with sand (FBCS). The average performance efficiencies of FBC, sand and FBCS were 95%, 67%, and 79% for turbidity, 81%, 19% and 56% for ammonium, 71%, 28% and 50% for phosphate 50 %, 61% and 46% for COD and 90%, 80% and 87% for fecal coliform respectively. The findings of this paper indicate that transformation of banana peel into biochar has a double advantage of treating greywater and minimizing the amount of waste that is disposed into the environment.



Greywater, Biochar, Sand