All

Industrial facilities emit pollutant air that contains volatile organic compounds (VOCs) and
reduced sulphur compounds (RSCs) which are nuisance, corrosive to materials and
dangerous to health. In recent years, biofiltration has replaced numerous conventional
processes (i.e. adsorption) due to its more effective, economical and environmental benefits.
Thus, increasingly industrial facility operators are adopting biofilters for removal of air
pollutants. Biofiltration takes place in bioreactors that are packed with media particles. On
these media particles micro-organisms form biofilms where biological oxidation takes place.
The new biofilter media developed in this study consists of a base material, hydrophobic
coatings, nutrients and binding agents. In this contribution, method of development,
evaluation and performance of this new bioreactor media are discussed.

The present study deals with the treatment of distillery spent wash by an ultrafiltration (UF)
membrane followed by reverse osmosis (RO) membrane on a pilot scale membrane setup.
The performance of the system was evaluated by varying applied pressure on the thin-film
composite polyamide (TFC-PA) UF and RO membranes. In the first stage, UF experiments
are carried out for concentration of effluents by removing the suspended solids (SS). RO has
effectively separated the total dissolved solids (TDS), chemical oxygen demand (COD),
biochemical oxygen demand (BOD), sulphate and potassium with the rejection efficiency of
97.9%, 96.8%, 97.9%, 99.7% and 94.65%, respectively. UF was effective for the separation of
SS with the rejection efficiency of 95.5%. The pollutant level in permeate are below the
maximum contaminant level as per the guidelines of the World Health Organization and the
Central Pollution Control Board (CPCB) of India specifications for effluent discharge (less than
1000 ppm of TDS and 500 ppm of COD).

The performance of a biological treatment of a PAH-contaminated soil was evaluated with
respect to its physicochemical and ecotoxicological properties. After six months, the biological
treatment led to an significant reduction of 2- and 3-ring PAHs and to a lesser extent to 4-ring
PAHs. As a consequence a significant decrease of the acute ecotoxicity was observed
passing from highly ecotoxic before treatment to non-ecotoxic according to Lactuca sativa
seedling and growth inhibition test and Eisenia fetida mortality test. This could be related to
the bioavailability of PAHs. Indeed, tests performed on aqueous leachates of the soil showed
a strong decrease of 2- and 3-ring PAHs correlated with a significant reduction of acute and
chronic ecotoxicity responses. The biological treatment led to the mutagenicity reduction and
the genotoxicity disappearance in the leachate. Thus, bioassays are complementary to
chemical analyses to evaluate the efficiency of a bioremediation process and to evaluate the
bioavailability of the organic pollutants as the total concentration of a contaminant is not the
only criterion to consider. The comparison of the ecotoxic responses allowed us to underline
the best sensitivity of the earthworm, Microtox, Alga and Ames bioassays among the tested
set. These bioassays could thus be good candidates to build a toxicity evaluation procedure
for PAHs contaminated/ remediated soils.

Stabilization/solidification (S/S) processes were utilized to immobilize lead (Pb) and tungsten
(W) in contaminated soils, the inclusion of W motivated by the use of the new W-based
ammunition. Artificially contaminated soils were prepared by mixing either kaolinite or
montmorillonite with 10% Pb and 1% W (all percentages by dry weight). Type I/II Portland
cement (PC), silica fume cement (SFC) and cement kiln dust (CKD) were used as S/S agents.
The S/S agents were added at 5, 10 and 15 % for a curing time of 1-, 7- and 28-days. The
toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching
procedure (SPLP) were used to evaluate the effectiveness of the treatments. X-ray powder
diffraction (XRPD) was used to investigate the crystalline mineral phases responsible for Pb
and W immobilization. The TCLP results showed that regardless of clay type and stabilizing
agents, the Pb concentrations decreased with increasing pozzolan content. PC and SFC
exhibited similar performance depending on the particular sample (not consistent with soil
type, dosage, and curing time). The most effective stabilizing agent on Pb leachability was PC
despite SFC being silica-enriched which should have contributed to its greater immobilization
of Pb. TCLP-W was immobilized below 1 mg l-1 in every case. The most effective stabilizing
agent on the SPLP-Pb leachability was CKD, consistently demonstrating among the lowest
concentrations for each soil type due to pH control. PC and SFC exhibited similar
performance depending on the particular sample (not consistent with soil type, dosage, and
curing time). The W concentrations in SPLP leachate were very low in most samples
indicating that W could be immobilized upon S/S processes even though W solubility is very
high at elevated pH conditions (662.9 mg l-1 at pH~11), and would remain immobilized under
SPLP exposure conditions. The XRPD results revealed that the formation of lead silicate
(Pb4SiO6), stolzite (PbWO4) and lead tungsten oxide (Pb0.29WO3) were strongly associated
with the immobilization of Pb in the S/S matrix.