HEAVY METALS IN WASTEWATER

>> REMOVAL B Biological methods

Submitted by :MANISH AMAN 2014UCE1538

Submitted to :Prof. A. B. Gupta sir,Faculty SE

HEAVY METALS IN WWTP

Activated sludge process does not remove most of the heavy metals efficiently

Heavy metals do not disappear nor react – they are either in the water or in the sludge!

Inhibition at high concentrations More load mainly from the use of

chemicals

HEAVY METALS REMOVAL METHODS !!!

BIOSORPTION

FIXED ACTIVATED SLUDGE PROCESS aka FAST

BIOLEACHING

EPS

BIOSORPTION

Biomass can be physically and chemically treated to increase adsorption.

Mane et. al. used chemically pretreated algal biomass for SELENIUM removal.

Algae isolates viz. Spyrogyra sp and Nostoc were treated with NAOH.

Also removes lead and Cadmium upto 60%.

FIXED ASP ---- FAST ( Hasani et. Al )

Submerged Fixed media. Increased surface area/vol ratio.Provides High Resistance to Shock

LoadsRemoval efficiencies (Pb,Cr,Ni)

increased with increase in biomass conc.

1

FAST FIXED MEDIA.

BIOLEACHINGIt is the extraction of

metals from SEWAGE SLUDGE with the help of bacteria.

Strategy : lower the pH ; increase Fe3+ conc.

Increased removal efficiencies(Cr,Cu,Zn) ; reaches max. in 4-10 days time.

Fe+2,S substrat

e

A. FERROOX-IDANS

Ph reduction&

metal solubilizati

on

THE PROCESS

REMOVAL USING EPSExtracellular polymeric substances produced by

Cloacibacterium normanense with crude glycerol is used.

Ni = 85% ; Al = 72% was removed

Factors affecting rate : contact time (12Hrs) ; concentration(35 mg/l) ; method

of extraction of EPS (centrifugation)

Good alternative as bioflocculant and low cost adsorbent.

THE PROCESSExtraction

of EPS

AS + crude GLYCEROL +

C.normanense

Microbial BIOPOLYMER

EXTRACTION OF EPS

THERMAL

EDTA RXN

CENTRIFUGATION

Refrences http://ascelibrary.org/doi/abs/10.1061/9780784479162.241 [1] Mane P. C, Bhosle A. B, Jangam C. M and Vishwakarma C. V,

“Bioadsorption of Selenium by Pretreated Algal Biomass”, Advances in applied science research, volume 2, pp-207-211, 2011.

[2] Jianlong Wang, Can Chen, “Biosorbents for heavy metals removal and their future”, Biotechnology Advances Vol.27, pp195–226, 2009.

Liu, F., Zhou, L., Zhou, J., Song, X., and Wang, D. (2012). "Improvement of sludge dewaterability and removal of sludge-borne metals by bioleaching at optimum pH." Journal of Hazardous Materials, 10.1016/j.jhazmat.2012.04.028, 170-177.

Bala subramanian, S., Yan, S., Tyagi, R.D., Surampalli, R.Y., 2010. EPS producing bacterial strains of municipal ww sludge: isolation, molecular identification, EPS characterization and performance for sludge settling and dewatering. Water Res. 44, 2253–2266.