This article contain the real case study, real diagrams and real results of implementation of Intensifier of Technological Process on the production facilities. To find out more about methods and ways of wastewater treatment from phenol, hexavalent chromium, heavy metal ions, organic compounds etc. you can visit our website www.fuelcleaning.globecore.com

1. We all talk about priority pollutants, about hazardous substances and discharge
to the atmosphere etc. which are dangerous for our environmental. Day by day we
adopt new laws and regulations to protect our green future. So, what is that
“priority pollutants”? Priority pollutants are highly toxic chemicals. The list of
these chemicals is quite large and includes thousands of items but today we will
speak about hexavalent chromium and methods of chromium-containing
wastewater treatment.
Hexavalent Chrome is priority pollutant and exists in several forms.
Industrial use of chromium includes in metal alloys such as stainless steel; protective
coatings on metal; magnetic tapes; and pigments for paints, cement, paper, rubber,
composition floor covering and other materials. Hexavalent chromium can be formed
when performing “hot work” such as welding on stainless steel or melting chromium
metal.
Exposure to this chemical is prevalent in different industrial applications. For
this reason there exist a lot of international Standards, Directives and Acts
which regulate utilization of chromium compounds and obligate to recycle
chromium-containing waste. Besides, removal of chrome from wastewater is also
needed to achieve the water quality level needed for reuse and recycling.
Wastewater which contains chromium and other heavy metals is classified as
high toxic wastewater. For this type of wastewater is required qualitative and
effective treatment.
There are different chromium removal methods such as chemical precipitation,
adsorption and biosorption, reverse osmosis, ion exchange, electrodialysis, photo-
catalysis. We offer to use breakthrough technology – electromagnetic vortex layer
with rotating ferromagnetic particles (AVS-100 or Intensifier of Technological
Process).
As we already noted in our previous articles, offered method is very effective
and allows reduce reagent consumption in 1.5-2 times, reduce energy consumption
is 2 times and decrease working area of treatment facilities in 10-15%.
Let us remember the result of sterilization of chromium-containing wastewater.
The results of sterilization of chromium-containing wastewater by using AVS
Basic
concentration
value Cr6+
,
mg/dm3
pH
process
Consumption
of iron sulfate,
% from
stoichiometric
consumption
Ferromagnetic
element mass,
g
Residual
Cr6+
content
after
purification,
mg/dm3
100 2
100
150
0
90 0
80 0,56

2. 100 4
90
150
0
80 0,9
590 2
100
200
0
90 0
80 0,8
1000 2,5
100
200
0
90 0,11
80 1,1
200 7,5 100 150 0,012
200 9,0
100
150
0
90 0,05
80 0,98
750 7,5-8,5 90 200 0,1-0,01
As you can see from the table, the content of chromium compounds in water
tends to zero after treatment by using AVS unit.
The goal of this article is to show how it works. How can we reach the
complete purification of wastewater from chromium? So, let`s begin.
Typically wastewater which contains chromium compounds treated in 2 stages.
First we need change hexavalent chromium Cr6+
to trivalent chromium Cr3+
. As result
we need obtain non-toxic materials.
Engineers from PC GlobeCore have investigated the effectiveness of AVS
usage in following versions: I – sterilization of chromium-containing wastewater by
reduction hexavalent chromium to trivalent chromium, II – combined neutralization
of chromium-containing and acid-base wastewater with simultaneous purification
from heavy metals ions.
The results of neutralization and purification from heavy metal ions are
follows:
Basic metal
concentration,
mg/dm3
pH process
Consumption of
Ca(OH)2, %
from
stoichiometric
consumption
Ferromagnetic
element mass, g
Residual
metal content,
mg/dm3
Fe2+;3+
= 130,0
7,5 90,0 200,
Fe2+;3+
- 0
Cu2+
= 50,0 Cu2+
- 0,12
Zn2+
= 45,0 Zn2+
- 0,063
Cd2+
= 10,0 Cd2+
- 0,07
Cr3+
= 120,0 Cr3+
- 0
Fe2+;3+
= 170,0 8,5 100,0 150 Fe2+;3+
- 0

3. Cu2+
= 40,0 Cu2+
- 0,018
Zn2+
= 28,0 Zn2+
- 0
Cd2+
= 5,5 Cd2+
- 0,011
Cr3+
= 100,0 Cr3+
- 0
Fe2+;3+
= 250,0
8,7 100,0 200
Fe2+;3+
- 0
Cu2+
= 65,0 Cu2+
- trace
Zn2+
= 35,0 Zn2+
- trace
Cd2+
= 2505 Cd2+
- 0
Cr3+
= 350,0 Cr3+
- 0
On the basis of performed investigations and production experiments of AVS
application for wastewater treatment, we offered and implemented manufacturing
schemes of wastewater treatment on different treatment facilities.
On the figure 1 is shown the diagram of simultaneous treatment of chromium-
containing and acid-base wastewater.
Figure 1. The diagram of simultaneous treatment of chromium-containing and
acid-base wastewater:
1 - mixing cylinder; 2 – tank for reducing agent (solution FeSO4); 3 – tank for
Na2CO3 solution preparation; 4, 7, 11 – pumps; 5 - tank for reducing agent; 6 – tank
for sulphuric acid; 8 – AVS unit, 9, 10 – settling tank; 12 - vacuum filter; 13 - dosing

4. unit; 14 - flow rate meter; 15 – reagent consumption control valve; 16 - sampling
unit; 17 – pH-meter
According to this diagram, sewage from shopfloors is alternately entering into two
mixing cylinders. When the first of these cylinders is filled by sewage and this
sewage is neutralized, to cylinder is fed the acid (in order to acidize the sewage to 2-3
pH level) and is fed reducing agent (sodium bisulfite). After 5-10 minutes mixing this
sewage is fed into AVS unit. (Before adding the sewage into AVS, this sewage was
filled by Na2CO3 to obtain the value of pH level at elevation 7,5-9). During couple
seconds of processing in AVS unit can be achieved complete and effective
wastewater treatment by reagents. During this time is completed restoration of Cr6+
to
Cr3+
and formation of Cr3+
hydroxide and other heavy metals. As reducing agent can
be used FeSO4 (ferrous sulfate).
In this case chromium restoration can be provided in each of acid and base medium.
The wastewater with metal hydroxides (after processing in AVS unit) enters the
settling tank for defecation and then – the sewerage or the water recycling (to the
shopfloors for engineering purpose). The sludge from settling tank is dewatered by
vacuum filters. Application of AVS unit allows obtaining the quality of treatment
lower than maximum permissible concentration, reduce reagent consumption in 1,5-2
times, reduce energy consumption in 2 times and decrease working area of treatment
facilities in 10-15%.
To find out more, please visit our website www.fuelcleaning.globecore.com