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Development and analysis of environmentally neutral, biodegradable, novel flocculants for drinking water treatment

Conaghan, Sharon (2013) Development and analysis of environmentally neutral, biodegradable, novel flocculants for drinking water treatment. Master of Science thesis, Dublin City University.

The objective of this work is a systematic study of the use of oleaginous-seed press-cake extracts of Moringa oleifera lam, hemp, sunflower, rapeseed, strawberry, lime and raspberry as bioflocculants for the removal of suspended solids in the process of coagulation and flocculation. A quantitative method for the analysis of the coagulation and flocculation process was developed to test the activity of the proteinaceous extracts, based on a spectrophotometric assay using kaolin to create the turbid water samples. This method could be used to measure both the initial flocculation activity rate as well as the total level of turbidity removal. Extracts of the press-cakes were tested for flocculation activity over a range of physical and chemical conditions, including initial turbidity, coagulant dosage, pH, ionic strength, and reducing agents dithiothreitol (DTT) and proteases (Proteinase K). Of the extracts studied, all showed significant levels of coagulation and flocculation activity with the exception of strawberry, raspberry and lime extracts. The level of turbidity reduction was calculated and in the order of decreasing activity, the most effective bioflocculants were found to be Moringa, sunflower, hemp and rapeseed. These results indicate that many common oleaginous-seed press-cake extracts show potential as bioflocculants in water treatment processes. The first section of this work used a simulated Jar test assay, which required the samples to be taken off-line and measured in a spectrophotometer. This process made accurate measurement of sedimentation often difficult and was extremely time consuming. This has led to the much needed continuous-reading on-line turbidity meters to be attached to the standard jar test apparatus. Therefore, the main aim of this section of the project was to develop and validate a new on-line quantitative process for the analysis of flocculation activity by attaching six Mettler Toledo Turbidity Transmitter TRB 8300 probes to a data acquisition system (Lab View). Each of the probes was then placed inside the vessels in the Phipps and Bird PB-700 Jar Test apparatus. Instrument calibration and process validation were examined by setting up a study on a multipoint calibration, limit of detection, and sensitivity. The effect of interfering light, flocculant colouring effects on the readings from the probes, measurement of flocculation rates and change in turbidity was examined. The results have demonstrated that all probes work within a 95% confidence interval for the measurement of the flocculation assay. This result will aid the efficiency and accuracy of the experimentation by allowing six independent on-line measurements of flocculation and sedimentation activity to be determined in parallel rather than the original single Jar test assay.
Item Type:Thesis (Master of Science)
Date of Award:March 2013
Supervisor(s):Marison, Ian
Uncontrolled Keywords:bioflocculants; flocculation; water treatment
Subjects:Biological Sciences > Biotechnology
DCU Faculties and Centres:DCU Faculties and Schools > Faculty of Science and Health > School of Biotechnology
Use License:This item is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 3.0 License. View License
Funders:Environmental Protection Agency
ID Code:17718
Deposited On:04 Apr 2013 13:28 by Ian Marison . Last Modified 19 Jul 2018 14:58

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