000			04103nam a2200409 4500
005			20260817171417.0
008			011298s1998 th r 0000|0 eng d
035			_a.b1173405x
099		9	_aAIT Thesis no. EV-98-20
100	1		_aAhmmed, Sohel
245	1	0	_aBioavailability of sludge-borne heavy metal as influenced by moisture regiemes
260			_aBangkok : _bAsian Institute of Technology, _c1998
300			_a104 leaves
490	1		_aThesis ; _vno. EV-98-20
500			_aA thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development
502			_aThesis (M.Eng.) - Asian Institute of Technology, 1998
520			_aSewage sludge usually contains significant heavy metals that may limit its land application. Heavy metals in sewage sludge have been shown to be less plant available and low concentration prior to the incubation process. In the present research DTP A test was conducted for metal bioavailability whereas sequential step extraction was employed to investigate metal speciation (into exchangeable, bound to carbonate, to Mn and Fe oxides, to organic matter and in residue phase) and the effect of high moisture (flooded sludge) as well as low moisture (wet and dry) content on metal speciation in incubation of Huay Kwang sewage sludge for heavy metal. The flooded sludge under specified period of time (10, 30 and 60 days) generally reduces bioavailability of metal except Mn, which was quite constant (20% of total heavy metal). The exchangeable and carbonated fractions (plant available) are also reduced and therefore the potential hazard of releasing metals from sludge through adsorption and complexation of the metals onto inorganic components to different extents for the different metals. Zn and Pb had distinct affinity to oxides whereas for Mn and Cd, dominant fractions were exchangeable or carbonated. Cu, Ni and Cr were associated mainly with organic or residual form (both of the forms are sparingly available). The present of fecal coliform (2 - 5 x 104 MPN/g dry wt.) indiGates the safe use in agricultural land but it should be monitored regularly. During the period of wet and dry condition (9 - 12% moisture content) the dry sludge releases more plant available metal due to stimulation of microor~anism and longer residual period. The bioavailability of Pb was found highest 54% in 30 C. In contrast the plant available fractions (exchangeable and carbonated) were found less in comparison with original one (except Zn and Cu), indicating safe use in agricultural purpose. Mn was decreased significantly in this condition. The residual fraction (mainly sulfides) was observed quite high amount for almost all metals from original or flooded sludge, indicating stable metal mineral complex and less threatening to plant.
650	1	0	_aHeavy metals _xBioavailability
700	0		_aPreeda Pakpian, _eChairperson
700	1		_aEckhardt, Ing. Heinz, _eExamination committee
700	0		_aApisit Eiumnoh, _eExamination Committee
710	2		_aThe Royal Danish Government, _eScholarship donor
810	2		_aAsian Institute of Technology. _tThesis ; _vno. EV-98-20
856			_3Full-Text _uhttp://203.159.5.9/ait-thesis/detail.php?q=B12740
907			_a.b1173405x _bmnait _cy
902			_a240407
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945			_lmnait
945			_lmnarc
942			_c20
942			_c40
909			_aBarcode : 30050120714315 _bCREATED : 1997-04-07 _cRECORD # : i12110358 _dLPATRON : 1012438 _eLCHKIN : 2000-05-02 _f# RENEWALS : 0 _g# OVERDUE : 0 _hIUSE3 : 0 _iTOT CHKOUT : 7 _jTOT RENEW : 8
909			_aBarcode : 30050120714307 _bCREATED : 1997-04-07 _cRECORD # : i1211036x _dLPATRON : 1018471 _eLCHKIN : 2006-07-12 _f# RENEWALS : 0 _g# OVERDUE : 0 _hIUSE3 : 0 _iTOT CHKOUT : 10 _jTOT RENEW : 10
909			_aBarcode : 30050160077912 _bCREATED : 2016-05-23 _cRECORD # : i12987773 _dLPATRON : 0 _eLCHKIN : - _f# RENEWALS : 0 _g# OVERDUE : 0 _hIUSE3 : 0 _iTOT CHKOUT : 0 _jTOT RENEW : 0
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