A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Environmental Engineering and Management Inter - University Program on Environmental Toxicology, Technology and Management

Thesis (M.Eng.) - Asian Institute of Technology - Chulabhorn Research Institute - Mahidol University, 2012

Bung Boraphet is the largest fresh water lake that located at Nakornsawan, the lower Northern of Thailand and covered area more than 300 km² in flooding season. It receives the water from 2 rivers before unite into Chao Praya river. This Lake has been considered as a great important natural resource and biodiversity, because many living things including over 30,000 people gain a lot of profits for a longtime. However, since 2009, it has been reported to be the contaminated area with heavy metals, especially Copper and Lead. Bioaccumulation of heavy metals by biota in surface water and by plants and animals in terrestrial environments can adversely affect humans. Most Heavy metals can be dispersed in sediment and water. In order to understand the bioavailability and its mobilization, more attention should be paid on the characteristic of sediment and practical treatment method. In this study, sediments were collected from 7 sites around Bung Boraphet Lake in December 2011. This study was divided into 3 phases and conducted in batch reactors. Firstly, to evaluate the amount of Cu (II) and Pb (II) in each environmental media, characterization of sediment and water was investigated. Secondly, the adsorption capacity and kinetics of Cu (II) and Pb (II) onto sediment was performed. Finally, sediment samples were spike with 500 mg/l of Cu(II) and 800 mg/l of Pb (II) and incubated for one and half month for simulating highly contaminated scenario, sequently, the capacity and treatment efficiency three absorbents; Activated carbon, Bentonite and compost were examined. The result reveal that pH of sediment is about 5.5-6 indicated the acidic condition and has a significant background Copper and Lead 47.3±3.3 and. 17.63±1.04 mg/L, respectively. It suggests that Lead had major trend of over standard which require remediation. Moreover, from fractionation study, the most common fraction of Copper was residual, with 30.54 g/kg (71.39%), whereas Lead was Fe-Mn oxide bond, with 10.85 g/kg (31.15%). This finding indicated that Lead has a high potential risk over Copper, because it highly existed in the mobile and exchangeable form. Based on study of adsorption kinetics of sediment, it demonstrated that single metal both Copper or Lead was rapidly adsorbed onto sediment more than its binary metal condition. It may due to the effect of ionic strength and competition between Copper and Lead for the sorption site. Furthermore, the behavior of Lead and Copper adsorption in both of single metals and binary metals were more associated with pseudo-second order model with high R2. The calculated capacity at equilibrium (qe) corresponded to the experimental values with low %{uF044}q. However, it revealed that qe of both binary system were fairly lower than single metal ion system. This may be an evidence of competition between metals on adsorbent. Additionally, Isotherm study exhibited that it is better fitted with the Langmuir isotherm for both Cu(ll) and Pb(II) and the maximum capacity for this sediment were Qm, Cu= 3690 mg/kg and Qm,pb= 3206.2 mg/kg, respectively. In contrast, the study of kinetics and isotherm of Activated carbon and Bentonite revealed that Freundlich isotherm could well explain the adsorption mechanism of both adsorbents and also provide its Freundlich constant (Kf) roughly 0.87-1.82 mg/g and 0.007-0.008 mg/g for Activated carbon and Bentonite, respectively. Finally, the removal efficiency of heavy metals focusing on Copper and Lead in each adsorbents could be put into order from high to low; Activated carbon > Compost >Bentonite.