Neeyana Paninthorn. Utilization of pulp and paper industrial waste to remove heavy metals from metal finishing wastewater . Master's Degree(Environmental Sanitation). Mahidol University. : Mahidol University, 2005.
Utilization of pulp and paper industrial waste to remove heavy metals from metal finishing wastewater
Abstract:
The feasibility of utilization of pulp and paper waste, lime mud (LM) and
recovery boiler ash (RB), for the pre-treatment of metal finishing wastewater (MFWW)
was investigated. LM and RB were sampled and determined for moisture
content, pH, chemical compositions and heavy metals. The MF-WW was also
analyzed for temperature, pH, Biochemical oxygen demand (BOD5), Chemical
oxygen demand (COD), Suspended solids (SS), Total dissolved solids (TDS), and
heavy metals. The optimum treatment conditions which gave the suitable pH range
and metal (chromium (Cr), copper (Cu), lead (Pb) and zinc (Zn)) removal efficiencies
at various dosages and reaction times were examined. The characteristics of
wastewater after treatment, such as pH, residual metal concentrations, some pollutants
(color, COD, SS and TDS) and sludge volume were also observed. Heavy metals in
the sediment were determined by leaching test.
LM and RB had low moisture content, low heavy metal contamination and
contained various carbonate compounds, which contributed to high pH value. MFWW
had a low pH value, high level of TDS and high contamination with Cr, Cu, Pb
and Zn. Application of LM and RB could significantly increase the pH value of MFWW
and remove heavy metals. Major treatment mechanisms were sorption and
precipitation. At selected treatment conditions, pH values were 7.65, 11.17, 8.70 and
9.16 after treatment with 80 and 110 g/L of LM and RB, respectively. LM gave better
treatment results than RB. At the optimum reaction time (45 minutes), the maximum
Cr (93%) and Cu (99%) removal efficiencies were obtained at 110 g/L of LM whereas
those of Pb (96%) and Zn (99%) occurred at using 80 g/L of LM. Most of some
pollutants were reduced after being treated with all selected treatment conditions.
Treatment with LM gave higher sludge volume than with RB. However, the
leachability of heavy metals was lesser. In addition, leachability of heavy metals in the
sediment of all selected treatment conditions was lower than the standard requirement.
Further study should put an emphasis on increasing the removal of TDS and
investigation of proper sludge treatment to ensure the safety of the environment. The
economic feasibility of using LM and RB should also be done to verify the feasibility
of applications.