2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology
P79 TREATING wASTEwATER by uSING OF
bIOCERAMIC FILTERS
A. VAŠKOVá, I. ŠTYRIAKOVá and V. SnOPKOVá
Department of Biotechnology, Insitute of Geotechnics of the
Slovac Academy of Sciences , Watsonova 45, 043 53 Košice,
Slovakia,
avaskova@saske.sk
Introduction
nowadays, the control and treatment of industrial effluents
has become one of the most important steps of the productive
process, since the regulatory offices have been very
rigorous about this subject 1 .
Heavy metals are a group of contaminants that are high
toxic to humans, animals, and aquatic lives and are commonly
found in many munic pal and industrial wastes 4 . The
toxicity of copper released into the environment has triggered
a number of studies aimed at its removal from aqueous
solutions. As a treatment approach, sorption in columns has
widely been used in water treatment 2 . The using of bioceramic
filters based on iron oxides, quartz sand, clay minerals,
and bacteria could be an alternative way to remove heavy
metals from industrial effluents. Iron oxides, a common constituent
of soils, sediments, and aquifers, have high surface
areas and are capable of adsorbing a significant quantity of
metals. They are dominant adsorbents in many environments
because of their capability to be finely dispersed and act as
coatings on other particles 3 . A number of studies on metal
uptake using quartz sands and clay minerals, have been conducted
and results have shown good adsorption properties
due to its metal-binding capacity and high surface area. Bacteria,
in particular, are effiecient sorbents of heavy metals,
although subtle differences can be seen between species and
under various physicochemical conditions. Previous studies
showed that the gram-positive bacteria Bacillus sp. was
able to retain several heavy metals as silicate minerals or as
oxyhydroxides at 20 and 4 °C under laboratory simulations
of natural conditions.
The concentration of some of the toxic metals are higher
than permissible discharge levels in effluents. It, therefore,
becomes necessary to remove these heavy metals from these
wastewaters by an appropriate treatment before releasing
them into the enviroment.
Experimental
The adsorption of copper by bioceramic filters was studied
by column technique. In this study two types of filters
were used and compared in sorption efficiency.
M a g n e t i t e P r e p a r a t i o n
Iron oxides can be easily synthetize in laboratory conditions.
Synthetic magnetite (Fe 3 O 4 ) used in this work was
prepared by partial oxidation of Fe 2+ solution at temperature
90 °C under anoxic conditions in the presence of nitrogen ions
-oxidizing agent. The surface area was 13 m 2 g –1 and particle
s499
size range from 0.05–0.2 µm. The main mineral phase was
confirmed by RTG diffraction, IR spectroscopy and Mössbauer
spectroscopy method.
Fig. 1. xRD-pattern of synthetic magnetite
C h a r a c t e r i z a t i o n o f Q u a r t z S a n d
a n d C l a y M i n e r a l s
Quartz sand used in this work was obtained from Šaštín
Stráže deposit (Slovakia) and composed of quartz (88–90 %),
feldspar (8–10 %), heavy minerals (1 %) and clay minerals
(1 %) of grain size 0–1 mm. The clay mineral used in this
study was bentonit composed of montmorillonite (60–80 %)
obtained from Jelšový potok deposit.
Table I
Chemical composition of quartz sand
Element [%] QS
SiO 2 92.7
Al 2 O 3 3.95
Fe 2 O 3 0.32
TiO 2 0.06
CaO 0.16
MgO 0.15
na 2 O 0.93
K 2 O 1.32
Cr 2 O 3 0.004
MnO 0.02
B a c t e r i a
In this study two bacterial strains were isolated from
the copper pollluted waste water of industry plant: Bacillus
megaterium and Pseudomonas diminuta. The resistance of
bacterial strains to copper was tested. The bacterial isolate
Bacillus megaterium could grow at a concentration ranging
from 52–260 mg Cu dm –3 and Pseudomonas diminuta at
a concentration max 52 mg Cu dm –3 , at temperature 25 °C.
Therefore Bacillus sp. isolate was used for this study. The
bacterial isolate Bacillus sp. was inoculated into flask containing
nutrient broth (Merck) and aerobically cultivated