REMOVAL OF SELECTED HEAVY METALS FROM POLLUTED WATER WITH SAND FILTRATION TECHNIQUE

Size: px

Start display at page:

Download "REMOVAL OF SELECTED HEAVY METALS FROM POLLUTED WATER WITH SAND FILTRATION TECHNIQUE"

Hector Davidson
5 years ago
Views:

1 The 2013 University of Oklahoma International WaTER Conference REMOVAL OF SELECTED HEAVY METALS FROM POLLUTED WATER WITH SAND FILTRATION TECHNIQUE G.K.Khadse, A.Kumar and P.K.Labhasetwar CSIR-National Environmental Engineering Research Institute, Nehru Marg, Nagpur-20, India

2 HEAVY METALS A heavy metal is a member of a loosely defined subset of elements that exhibit metallic properties. It mainly includes the transition metals, some metalloids lanthanides, & actinides. Many different definitions have been proposed some based on density, some on atomic number or atomic weight and some on chemical properties or toxicity. There is an alternative term toxic metal. The presence of heavy metals in the environment is of major concern because of their toxicity to many life forms. According to WHO, the metals with most immediate concern are: Cr, Cu, Mn, Fr, Co, Ni, Zn, Hg, Pb.

3 Sources and Sinks of Heavy Metals Heavy metals Abundance in nature Enter water cycle through geochemical processes. Metals added by human activities: o Manufacturing o Construction o Agriculture o Transportation

4 Metal Toxicity 1. ACUTE: Soluble copper gastroenteritis symptoms with nausea 2. CHRONIC: Cadmium and lead accumulate in body tissue 3. SYNERGISTIC: Certain metals are more toxic in combination with other metals or under specific environmental condition e.g. Cadmium toxicity increases in the presence of Cu/Zn, ph, T hardness, SS, CO 2 4. MUTAGENIC / TERATOGENIC: Certain metals, combine with organic compounds, may produce changes in genetic makeup or develop abnormal tissue in embryo.

5 Treatment Alternatives for Metal Removal Methods for removing dissolved heavy metal ions include chemical precipitation, chemical oxidation or reduction, filtration, ion exchange, electrochemical treatment, membrane technology and evaporation recovery Limitations of the technology processes: require expensive equipment & monitoring system, high reagent or energy requirements, generation of toxic sludge that require disposal

6 SAND FILTRATION TECHNIQUE

7 Objectives of the study To study the efficiency and performance of sand filter units for removal of select heavy metals viz. Cr, Cu, Mn, and Zn. To investigate the effect of - ph, injection rate (IR) hydraulic loading rates (HLR), initial conc. and contact time on removal of select heavy metals To develop an economically cheap and efficient device for removal of select heavy metals from water. To extrapolate the technique in the area, where water sources are contaminated with heavy metals.

water followed by 1% acid water & again with water and airdried Reactor filled with gravels up to 5

8 THE SAND FILTER UNIT Comprised of: Reactor (60 L), Filter Collection tank Diameter: 41.5 cm, height: 45 cm, area: 1352 cm 2 Locally available sand and gravels Wash gravels/sand with water followed by 1% acid water & again with water and airdried Reactor filled with gravels up to 5 cm at bottom followed by sand up to 40 cm SAND Effective size (D10) = 0.3 mm Uniformity coefficient (U=D60/D10) < 3.

9 XRD spectrum of sand

10 Effect of HLR on removal efficiency of different influent conc. of Cu at different IRs IR : m 3 /hr Co = 1.89 (ppm) Co = 4. (ppm) Co = 9.43 (ppm) Co =14.21 (ppm) Co = (ppm) IR m 3 /hr Co = 1.89 (ppm) Co = 4. (ppm) Co = 9.43 (ppm) Co = (ppm) Co = (ppm) IR m 3 /hr Co = 1.89 (ppm) Co = 4. (ppm) Co = 9.43 (ppm) Co = 14.21(ppm) Co = (ppm)

11 Effect of HLR on removal efficiency of different influent conc. of Cr at different IRs IR : m 3 /hr Co = 1. (ppm) Co= 4. (ppm) Co = 9.88 (ppm) Co= (ppm) Co = (ppm) IR : m 3 /hr Co = 1. (ppm) Co= 4. (ppm) Co = 9.88 (ppm) Co= (ppm) Co = (ppm) IR : m 3 /hr Co = 1. ppm Co= 4. (ppm) Co = 9.88 (ppm) Co= (ppm) Co = (ppm)

12 Effect of HLR on removal efficiency of different influent conc. of Zn at different IRs IR : m 3 /hr Co = ppm Co= (ppm) Co = (ppm) Co = (ppm) Co = (ppm) 85 IR : m 3 /hr Co = ppm Co= (ppm) Co = (ppm) Co = (ppm) Co = (ppm) IR : m 3 /hr Co = ppm Co= (ppm) Co = (ppm) Co = (ppm) Co = (ppm)

13 Effect of HLR on removal efficiency of different influent conc. of Mn at different IRs IR : m 3 /hr Co = 2.04 ppm Co= 3. (ppm) Co = 5. (ppm) Co= 6.85 (ppm) Co = 9.67 (ppm) IR : m 3 /hr Co = 2.04 ppm Co= 3. (ppm) Co = 5. (ppm) Co= 6.85 (ppm) Co = 9.67 (ppm) IR : m 3 /hr Co = 2.04 ppm Co= 3. (ppm) Co = 5. (ppm) Co= 6.85 (ppm) Co = 9.67 (ppm)

14 Effect of influent IRs on removal efficiency of different influent conc. Cu I R= m3/hr I R= m3/hr I R= m3/hr Cr I R= m3/hr I R= m3/hr I R=0.036 m3/hr Influent conc. (ppm) Influent conc. (ppm) 85 Zn I R= m3/hr I R= m3/hr I R= m3/hr Mn I R= m3/hr I R= m3/hr I R= m3/hr Influent conc. (ppm) Influent conc. (ppm)

15 Effect of ph on removal efficiency of different conc. of Cu ph 3 ph 5 ph 7 Co = 1.9 mg/l Co = 4.85 mg/l Co = 9.86 mg/l Co = mg/l Co = 18. mg/l Co = 1.8 mg/l Co = 4.71 mg/l Co = 9.92 mg/l Co = 14.4 mg/l Co = 18.6 mg/l Co = 1.79 mg/l Co = 4.9 mg/l Co = 9.43 mg/l Co = 14.21mg/L Co = 18.5 mg/l ph 4 Co = 1.82 mg/l ph 6 Co = 4. mg/l Co = 9.87 mg/l Co = mg/l Co = 18.7 mg/l ph 8 Co = 1.8 mg/l Co = 4.9 mg/l Co = 9.85 mg/l Co = mg/l Co = 18.7 mg/l Co = 1. mg/l Co = 4.92 mg/l Co = 9.88 mg/l Co = 14.27mg/L Co = 18.4mg/L

16 Effect of ph on removal efficiency of different conc. of Cr ph 3 Co = 1.9 mg/l Co = 4.8 mg/l Co = 9.9 mg/l Co = mg/l Co =18.82 mg/l Co = 2.03mg/L Co = 4.89 mg/l Co =9.88 mg/l Co = mg/l Co =18.5 mg/l ph 4 ph 5 ph 6 ph 7 Co = 1.mg/L Co = 4.9mg/L Co =9.88mg/L Co = 14mg/L Co =18.4mg/L ph 8 Co = 2.00mg/L Co = 4.9 mg/l Co =9.89 mg/l Co = mg/l Co =18.8 mg/l Co = 1.7mg/L Co = 4.8 mg/l Co =9. mg/l Co = mg/l Co =18.5 mg/l Co = 1.mg/L Co = 4.89 mg/l Co =9.87 mg/l Co = 14.21mg/L Co =18.3mg/L

17 Effect of ph on removal efficiency of different conc. of Zn ph ph 5 ph 7 Co = mg/l Co = mg/l Co = mg/l Co = mg/l Co = 86.4 mg/l Co =16.49 mg/l Co =34.12 mg/l Co =55. mg/l Co = 71.8 mg/l Co =86 mg/l Co =16.55 mg/l Co =34.56 mg/l Co =55.6 mg/l Co = mg/l Co =85.4 mg/l ph ph 6 ph 8 Co = mg/l Co =34.5 mg/l Co = mg/l Co = mg/l Co = 86.1 mg/l Co =16.88 mg/l Co =34.3 mg/l Co =56.5 mg/l Co =71.68 mg/l Co =16.23 mg/l Co =16.37 mg/l Co =34.08 mg/l Co =55.1 mg/l Co =71.92 mg/l Co =85.1 mg/l 85 85

18 Effect of ph on removal efficiency of different conc. of Mn ph 3 ph 5 Co = 2.0mg/L Co = 3.89 mg/l Co = 5. mg/l Co = 6.9 mg/l Co = 9. 6 mg/ L Co = 2.07mg/L Co = 3. mg/l Co = 5.89 mg/l Co = 6.91 mg/l Co = 9.83 mg/l Co = 2.04 mg/l Co = 3. mg/l Co = 5.9 mg/l Co = 6.85 mg/l Co = 9.67 mg/l ph 4 ph 6 ph 7 ph 8 Co = 1. mg/l Co = 3.9 mg/l Co = 5.92 mg/l Co = 6.89 mg/l Co = 9.55 mg/l Co = 2.1 mg/l Co = 3.89 mg/l Co = 5.92mg/L Co = 6.88 mg/l Co = 9.67 mg/l Co = 1. mg/l Co = 3.9 mg/l Co = 5.87 mg/l Co = 6.82 mg/l Co = 9.71 mg/l

19 Findings The removal efficiency of heavy metals is decreased as the IR increased. Although sand is quite effective even at IR of m 3 /hr, yet the IR of m 3 /hr is most effective for the used filter units. The solution ph does not have a significant impact on the removal efficiency of Cr, Cu, Mn and Zn. Since higher ph results in precipitation of Cr rather than adsorption, it is recommended to acidify the influent solution prior to treatment. The adsorption of select heavy metals is in the order of Cr > Cu > Zn > Mn. This method involves less capital cost, highly efficient and practicably feasible for developing countries. The results of investigation will be useful for the removal of metals from effluents containing these metals.

20 Thanks

Chemical treatment of acid mine drainage. Anna Gulkova, Water and Environmental Engineering, Aalto University

Chemical treatment of acid mine drainage Anna Gulkova, Water and Environmental Engineering, Aalto University 1 Contents Acid mine drainage formation Problems associated with acid mine drainage Treatment