Study on Removal of Algae by Coagulation with Magnetic MnFe2O4 Being Recycled from Drinking-Water Treatment Sludge
| Autor: | Yeh, Chin-Wha, 葉清華 |
|---|---|
| Rok vydání: | 2017 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 105 In Taiwan, the water treatment plant (WTP) will add pre-oxidizing chemical (such as NaOCl) before coagulation/sedimentation to alter the activity or surface properties of algae to improve the algae removal efficiency. However, addition of chlorine type disinfectant will produce harmful byproducts, e.g trihalomethanes (THMs). On the other hand, most of the landfills in Taiwan are saturated and the treatment cost of WTP sludge is getting higher in recent years. Hence the recycle of large amount of WTP sludge will save a lot of clearance cost. In this study, considering best of both worlds, the WTP sludge was converted to “Iron and Manganese Oxide Magnets (IMOM)” and used as adsorbent for the algae removal. Not only the sludge treatment cost will largely decrease but also the goal of waste recycle can be achieved. In this work, synthetic water sample with specific amount of algae was prepared befor implementing the oxidation and coagulation experiments. Then PACl or FeCl3 was added respectively with IMOM to evaluate the turbidity and algae removal efficacy. The results show that removal rate of algae treated with PACl and IMOM is 97.4%, whilst that of PACl and NaOCl is 91.0%. Using IMOM instead of NaOCl improve the algae removal. Moreover, addition of NaOCl will disintegrate algae and release extracellular material. As for removing algae by adding IMOM alone, the rate is just 68.4%. Recovery of spent IMOM was also evaluated. The recovery rates of spent IMOM are both higher than 95% for adding IMOM and PACl simultaneously and adding IMOM alone. Furthermore, the spent IMOM shows higher algae removal rate than the fresh IMOM. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|