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Title:	Toxicity investigation of landfill leachate using bioassays and its treatment and detoxification using zeolite and chitosan
Authors:	Jaffer Younis Mefleh Al-Kassasbeh (P32104)
Supervisor:	Salmijah Surif, Prof. Dr.
Keywords:	Leachate Toxicity testing Zeolites
Issue Date:	15-Oct-2012
Description:	In this study, the use of zeolite and chitosan to remove contaminants and toxicity of landfill leachate was investigated. A suite of bioassays comprising of common carp (Cyprinus carpio L.), prawn (Machrobrachium lanchesteri), algae (Selenastrum capricornutum), and tomato (Lycopersicon esculentum) was employed for toxicity testings. Leachates were collected from Air Hitam (AHL), Ampar Tenang (ATL), and Sungai Sedu (SSL) landfills in Selangor and their physico-chemical characteristics, as well as toxicity determined. The toxicity data obtained were statistically evaluated using EPA computer program based on Finney's probit analysis method. Different test organisms showed different sensitivities to leachates. The 96h LC50 values of landfills leachates collected from AHL, ATL, and SSL for C. carpio were found to be 1.13%, 2.34% and 3.82%, respectively and for M. lanchesteri were 0.65%, 1.64%, and 3.01% respectively. The mean 96h EC50 values for the same three leachates using S. capricornutum were 1.4%, 2.55%, and 3.74%, respectively and for L. esculentum were 12.13%, 25.88%, and 37.26% respectively. These toxicity tests results indicated a high potential toxicity for landfills leachates with the highest toxicity rate recorded for AHL leachate. The removal of important contaminants, namely ammoniacal nitrogen (NH4-N), chemical oxygen demand (COD), phosphate (PO4-3), colour, and total suspended solids (TSS) from AHL (the most toxic leachate) by rice husk ash synthetic zeolites (NaY and NaP) and chitosan, which had been previously characterized, was then investigated. Using batch study, the effect of pH, dosage, contact time, mixing rate, and leachate initial concentration on the removal of COD and NH4-N from the leachate by chitosan and NaY, respectively were examined. Combined treatment of NaY and chitosan was also carried out. The raw untreated leachates had variable COD and NH4-N concentrations of between 693-7765 mg/L and 277-957 mg/L, respectively among the different sites. The highest removal for NH4-N (65.19%) was accomplished by NaY at 30 g/L dosage, pH 6, 120 min contact time, and 200 rpm mixing rate. Chitosan removed highest COD (58.04%) at a dosage of 5 g/L, pH 4, 60 min contact time, and 150 rpm mixing rate. The highest phosphate removal of 96.93% was achieved by NaY, followed by NaP (79.95%) and chitosan (60.24%). Chitosan caused highest removal for colour (70.18%) and TSS (82.39%). For NH4-N removal using zeolites, Langmuir isotherm model yields better fit than the Freundlich model (r2=0.998 vs 0.932) while for COD removal using chitosan, both Langmuir and Freundlich models showed equally good fit with the experimental data (r2= 0.997 vs 0.951). The obtained results from the combined treatment using NaY and chitosan revealed higher removal for COD (83.19%), NH4-N (87.27%), PO4-3 (99.57%). Toxicity testing of the treated leachate using S. capricornutum and M. lanchesteri, showed increases of 96h EC50 and IC50 to 36.12% and 21.15%, respectively compared to 1.4% and 0.67% for untreated samples, indicating significant decrease in leachate toxicity. This study showed that synthetic zeolites and chitosan can significantly remove contaminants as well as potential toxicity from landfill leachate.,Tesis ini tiada Perakuan Tesis Sarjana / Doktor Falsafah"
Pages:	274
Call Number:	TD795.7.K346 2012 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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