BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
The present invention relates broadly to a process as well as an apparatus
for cyanide treatment of effluents in a multi-zone multi-media unit with
attached growth trickling filter, and more particularly, to a process for cyanide
treatment of effluents in which two different types of biological slimes are
formed under different process conditions and an apparatus using the said
process
2. DESCRIPTION OF THE PRIOR ART
Known prior arts for waste water treatment/effluents treatment process
include US Pat No. 5,160,632; US Pat. No. 4,105,545; US Pat No
6,287,847; WO Pat. No. 0035816; US Pat. No. 4,440,644, GB Pat No
741,232; GB Pat No 353,625; US Pat. No. 5,264,192; US Pat Application
No 2002074286 and US Pat. No. 6,565,750.
Both the process and apparatus for waste water treatment/effluents
treatment have been reported in US Pat. No. 5,262,051; US Pat No
6,767,464 and WO Pat. No. 0168536.
Some non-patent documents relate to the waste water treatment /
effluents treatment process and apparatus. A "bio-treatment of oil-bearing
coke-oven wastewater in fixed-film reactor" is disclosed in the Environmental
Engineenng Science Journal of July 2000 issue [Vol. 17, No 4, Pages 221-
226] by Suresh Kumar, Vaidya, Shivaraman and Bal. Prasad, Singh reported
an "application of activated carbon for treatments of wastewater with special
emphasis on coke oven effluents" in the Indian Journal of Environmental
Protection in 1994, Volume 14, and Issue 9, 695-699. A relevant document
has been found in the Indian Journal of Environmental Health (2003 Jan,
Volume 45, Issue 1, pages 29-38). This document, as reported by Suresh
Kumar, Vaidya, Shivraman & Bal, relates to "performance evaluation of a full-
scale coke oven wastewater treatment plant in an integrated steel plant"
US Pat No. 5,160,632 discloses a process for removing cyanide anions
from waste waters using halogen-free ferric salts. The process is particularly
effective when treatment of cyanide waste waters is done by adding ferric
sulfate while adjusting pH of the waste waters with a halogen-free acid, such
as sulfunc acid, to a pH ranging from about 3.0 to 5.0. The fernc ferricyanides
formed are agglomerated and flocculated using synthetic polymers along with
whatever other dispersed or suspended solids may be present in the waste
waters, and this dense sludge is separated in a clarifier. Cyanide removal is at
least 80%, relative to initial cyanide concentrations, and preferably 90%
removal or higher. Cyanide wastes from coke oven off gas scrubbing waters
are particularly waste waters amenable to this treatment

US Pat No 5,262,051 narrates an apparatus for biological treatment of
water and waste of the attached-growth type, constructed by disposing long
fiber bundles formed by binding a large number of monofilaments, upward
and downward in a zigzag formation in a vessel, fixing substantially the upper
and lower angle portions thereof, and particularly incorporating supports for
supporting the angle portions of the long fiber bundles disposed upward and
downward in a zigzag formation, into a part of a frame assembled in advance
together with frame members, the apparatus being capable of high-volume
treatment, causing little clogging, towering construction costs, and capable of
stable long-term operation.
US Pat 6,565,750 and US Pat. Application No.2002074286 disclose a
trickling filter system for biological nutrient removal. The said document
provides a two-stage process for treating wastewater that subjects the influent
to anoxic and oxic filtering processes. The first stage performs anoxic
nitrification i e , the conversion of nitrate to nitrogen gas by bacteria operating
in the absence of oxygen. Influent (effluent from the primary clarifiers) is fed
into the bottom of the anoxic dentirification tank, preventing contact with the
atmosphere and thus reducing the amount of unwanted dissolved oxygen
The influent passes upwards through a layer of sludge biomass before
contacting bacteria coated media, which performs the denitrification process
This arrangement permits the influent to contact the sludge and the biomass
to circulate through the filter, enhancing deoxygenation and the performance
of the system
A method for treating cyanide-contaminated water in order to remove
dissolved (e g free) cyanide (HCN and/or CN.sup.) therefrom is disclosed in
US Pat No 5,264,192.
GB Pat No 741,232 talks about a process for treating a coke-oven
effluent or similar aqueous liquor low or substantially free from thiocyanate or
thiosulphate. The process of GB Pat. No. 741232 consists in passing the
coke-oven effluent successively through a bed of an alkali-activated anion-
exchange resin having pores that are large in relation to those of normal
anion-exchange material and a bed of activated carbon- the pores are
sufficiently large to permit entry of anions of colouring matter contained in the
liquid These steps, as per the said document, may be preceded by removal
of ammonia by distillation and removal of any thiocyanate and thiosulphate
either by passage through anion-exchange material having pores of the
normal small size or by the process described in GB 723,610. The large-pore
anion-exchange resin may be a bed of resin gel produced by the
condensation of an aldehyde with a phenol, an aromatic amine or an aliphatic
amine, or with more than one of these, in an aqueous medium with no or
substantially no drying of the gel. The inventor has found in the practice of the
invention that the condition of the final liquor is improved and the useful life of
the activated carbon is prolonged.
US Pat No. 6,767,464 describes systems for treating water containing
unwanted contaminants. This patent relates to waste water treatment systems
including biological media used to aerobically or anaerobically treat solid and

liquid waste in water for large and small-scale waste water systems in a way
that minimizes the size of the system required to output high-quality,
environmentally suitable water that is depleted of ammonia, nitrites, nitrates
and other contaminants.
US Pat. No. 4,440,644 identifies a method for the biological removal of
free and complex cyanides and thiocyanates from water Cyanides,
thiocyanates and metal cyanide complexes present in an aqueous solution
can be biologically degraded by certain mutant strains of the species
Pseudomonas paucimobilis. Such microorganisms are useful in the biological
treatment of cyanide-containing wastewaters. The present document mainly
talks about microorganisms suitable for biological removal of free and
complex cyanides and thiocyanates from water. A similar patent document,
WO Pat No 0035816 deals with biodegradation of thiocyanate and cyanide
This document narrates a method of treating a solution, which contains at
least one of thiocyanate and cyanide. Their method includes the step of
contacting the solution in a first reactor with at least the active bacteria
contained in a microbial culture of the type deposited at the Australian
Government Analytical Laboratories under the Accession number NM
98/11331.
It is seen from the above-cited documents that some of the prior patent
and non-patent literatures deal with two stage filters It is seen that sometimes
two stage filters are used but these are essentially two single stage filters
placed in senes.
From the prior works relevant and related to the present invention it is
found that in a conventional apparatus for cyanide treatment of effluents there
is only one media for filters. Biological slimes used therein are of two types,
one is aerobic and the other anaerobic. In the conventional process same
conditions are used to produce the two different biological slimes This leads
to poor process control. In conventional process there is no means to arrest
cyanide spikes that is inhibitory to the biological treatment process. Even bed-
height of the single media is fixed irrespective of the form of cyanide in the
influent in conventional process. Thus, while aerobic and anaerobic slime
biodegrades differently, there is no provision to adjust the bed-height
according to process requirements.
In the conventional process, aeration is performed by natural, forced, or
induced draft However, there is no control on the aeration for anaerobic
microorganisms Maintaining the anaerobic condition is dependent on the
thickness of aerobic biological slime, which depends upon several process
conditions
Thus, it would be desirable to devise a process for cyanide treatment of
effluents in a multi-zone multi-media unit with attached growth trickling filter
and an apparatus using the said process that obviates the above raised
problems.

3. SUMMARY AND OBJECTS OF THE INVENTION
Accordingly, the present invention is directed to propose a process for
cyanide treatment of effluents in a multi-zone multi-media unit with attached
growth trickling filter and an apparatus thereof
An object of the present invention is to provide an apparatus and a
process for cyanide treatment of effluents in a multi-zone multi-media unit with
attached growth trickling filter in which two different types of biological slimes
are formed under different process conditions
Another object of the present invention is to provide an apparatus and a
process for cyanide treatment of effluents in a multi-zone multi-media unit with
attached growth trickling filter thereby ensuring a proper process condition for
aerobic and anaerobic biodegradation.
Another further object of the present invention is to provide an apparatus
and a process for cyanide treatment of effluents in a multi-zone multi-media
unit with attached growth trickling filter having adjustable bed-height for both
the aerobic and anaerobic biodegradation process condition
Still another object of the present invention is to provide an apparatus and
a process for cyanide treatment of effluents in a multi-zone multi-media unit
with attached growth trickling filter having a buffering zone to reduce cyanide
spike that is inhibitory to the biological treatment process
To achieve these and other advantages and in accordance with the purpose
of the present invention, as embodied and broadly described, the apparatus
for cyanide treatment of effluents in a multi-zone multi-media unit with
attached growth trickling filter having a bed of highly permeable medium to
which microorganisms are attached to and through which waste water is
percolated or trickled characterized by that the apparatus has
multi-zones (1, 2, 3) for facilitating aerobic process;
a multi-media filter consisting of variety of plastic packing materials, rock, iron
ore and stone slag as media,
a transition zone (2) to form a buffer zone (2) in order to act as cyanide (CN)
moderator,
a buffering zone (2) to reduce high cyanide (CN) spike that is inhibitory to the
biological treatment process;
a first tube (4) with provisions for fitting sheet / disc with holes in its upper part
for uniform distribution of liquid and the said tube (4) having provisions for
fitting sheet / disc with holes, cones, pressure manometer, teflon key and
other auxiliary attachments (8) in lower part,
a second (5) and third tube (6) with provisions for fitting sheet / disc with holes
in its upper part for uniform distribution of liquid and the said tubes (5, 6)
having provisions for fitting sheet / disc with holes, cones, pressure
manometer, teflon key and other auxiliary attachments (8) in lower part;
a fourth tube (7) with provisions for fitting teflon tap (8) in its lower part for
collection of drainage,

a heavy metal-stand (9) having a plurality of adjustable clamping members
(10),
an adjustable base (12) located at lower part of the apparatus; and
a platform (11) in upper part with the said stand to hold a tank / feed vessel
(13) of suitable capacity having a pressure manometer (8);
in which all the said pressure manometer, teflon key, sheet / disc and other
auxiliary attachments (8) are provided in such a way that the said elements
(8) can be removed and fitted in order to achieve ease of maintenance and
interchangeability and the bed-height for the process for cyanide treatment
of effluents using the said apparatus is variably adjustable.
The said apparatus for cyanide treatment of effluents in a multi-zone multi-
media unit with attached growth trickling filter having a bed of highly
permeable medium to which microorganisms are attached to and through
which waste water is percolated or trickled wherein all the said four tubes are
fitted vertically and means are provided in order to achieve water proof / leak
proof fittings during the said apparatus's installation
The said apparatus for cyanide treatment of effluents in a multi-zone multi-
media unit with attached growth trickling filter having a bed of highly
permeable medium to which microorganisms are attached to and through
which waste water is percolated or trickled wherein the said plurality of
clamping members and the said base located at lower part can be fitted
anywhere in the said heavy-metal main stand
The said apparatus for cyanide treatment of effluents in a multi-zone multi-
media unit with attached growth trickling filter having a bed of highly
permeable medium to which microorganisms are attached to and through
which waste water is percolated or trickled wherein the said attached growth
trickling filter is split up into different zones including aerobic and anaerobic
zones
The present invention also narrates a process for cyanide treatment of
effluents in a multi-zone multi-media unit with attached growth trickling filter
having a bed of highly permeable medium to which microorganisms are
attached to and through which waste water is percolated or trickled using the
said apparatus
The said process for cyanide treatment of effluents in a multi-zone multi-
media unit with attached growth trickling filter having a bed of highly
permeable medium to which microorganisms are attached to and through
which waste water is percolated or trickled comprising the steps of:
(i) aerating of effluents in a controlled manner,
(n) maintaining suitable bed-height at different zones (1, 2, 3) for facilitating
aerobic process during the treatment of different forms of cyanide;
(in) maintaining suitable bed-height at different zones (1, 2, 3) for facilitating
anaerobic biodegradation process condition during the treatment of different
forms of cyanide, and
iv) optimising hydraulic and organic loading, at various load levels

The said process for cyanide treatment of effluents in a multi-zone multi-
media unit with attached growth trickling filter having a bed of highly
permeable medium to which microorganisms are attached to and through
which waste water is percolated or trickled wherein at a particular ratio of
plastic, iron ore and stone respectively the optimized value of the said bed-
height ratios is established
The said process for cyanide treatment of effluents in a multi-zone multi-
media unit with attached growth trickling filter having a bed of highly
permeable medium to which microorganisms are attached to and through
which waste water is percolated or trickled wherein aeration in aerobic zone is
performed by forced draft.
The said process for cyanide treatment of effluents in a multi-zone multi-
media unit with attached growth trickling filter having a bed of highly
permeable medium to which microorganisms are attached to and through
which waste water is percolated or trickled wherein the said aerobic zone is
on plastic media and the said anaerobic zone is on stone media
The said process for cyanide treatment of effluents in a multi-zone multi-
media unit with attached growth trickling filter having a bed of highly
permeable medium to which microorganisms are attached to and through
which waste water is percolated or trickled wherein growth of two types of
biological smiles are independent of each other.
The said process for cyanide treatment of effluents in a multi-zone multi-
media unit with attached growth trickling filter having a bed of highly
permeable medium to which microorganisms are attached to and through
which waste water is percolated or trickled wherein depending upon the
suitability of requirements of the said process, the said media can be changed
and proportions of each elements of the said media can also be changed
upon requirements of the said process.
The vanous features of novelty that characterise the invention are pointed
out with particularity in the claims annexed to and forming a part of this
disclosure For a better understanding of the invention, its operating
advantages and specific objects attained by its uses, reference is made to the
accompanying drawings and descriptive matter in which preferred
embodiments of the invention are illustrated
4. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
A more complete understanding of the present embodiments and
advantages thereof may be acquired by referring to the following description
taken in conjunction with the accompanying drawings, in which like reference
numbers indicate like features, and wherein:
Fig 1 shows a conventional trickling filter with single media,

Fig 2 is a schematic diagram illustrating the apparatus using the process for
cyanide treatment of effluents in a multi-zone multi-media unit with attached
growth trickling filter, according to the present invention;
Fig 3 is a plot illustrating the effect of splitting up of the aerobic and anaerobic
zone on the two different media, according to the present invention;
Fig 4 is the bed-heights of zones in different media, according to the present
invention, and
Fig 5 illustrates the percentage cyanide (CN) reduction versus flow rate,
according to the present invention.
5. DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO
THE ACCOMPANYING DRAWINGS
Fig 1 shows a simplified trickling filter with single media. The effluent to be
treated is sprinkled from the top of the trickling filter. The media inside the
filter serves to increase the residence time of the effluent by obstructing the
flow of fluid and allowing mass transfer from the air supplied by natural draft
from the bottom Fig. 1 also delineates the two layers of biological slimes
formed on the surface of the media. On the inner side is the anaerobic layer
and on the outer side is the aerobic microorganisms layer. Sometimes two
stage filters are used but these are essentially two single stage filters placed
in senes
Fig 2 is the apparatus utilizing the process for cyanide treatment of
effluents in a multi-zone multi-media unit with attached growth trickling filter,
according to the present invention. The growth trickling filter, according to the
present invention, has a bed of highly permeable medium to which
microorganisms are attached to and through which waste water is percolated
or tnckled. The apparatus has multi-zones (1, 2, 3) for facilitating aerobic
process, a multi-media filter consisting of variety of plastic packing materials,
i e., rock, iron ore and stone slag as media and a transition zone (2) to form a
buffer zone in order to act as cyanide (CN) moderator. A buffering zone to
reduce high cyanide (CN) spike that is inhibitory to the biological treatment
process is also included in the said apparatus.
The constructional features of the said apparatus, according to the present
invention and indicated in Fig. 2, includes a first tube (4) of suitable length and
diameter having provisions for fitting sheet / disc with holes and other auxiliary
attachments (8) in its upper part for uniform distribution of liquid The said first
tube (4) have provisions for fitting sheet / disc with holes, cones, pressure
manometer, teflon key and other auxiliary attachments (8) in lower part
A second (5) and third tube (6) of suitable length and diameter having
provisions for fitting sheet / disc with holes and other auxiliary attachments (8)
in its upper part for uniform distribution of liquid is also included in the said
apparatus. The said second and third tubes have provisions for fitting sheet /

disc with holes, cones, pressure manometer, teflon key and other auxiliary
attachments (8) in lower part
Another tube, called fourth tube (7), of suitable length and diameter having
provisions for fitting teflon tap (8) in its lower part for collection of drainage is
fitted to the said apparatus
All the said four tubes (4, 5, 6, 7) are fitted vertically and means are
provided in order to achieve water proof / leak proof fittings during the said
apparatus's installation.
The said apparatus, according to the present invention, further includes a
heavy metal-stand (9) having a plurality of adjustable clamping members (10),
an adjustable base (12) located at lower part of the apparatus, and a platform
(11) in upper part with the said stand (9) to hold a tank / feed vessel (13) of
suitable capacity having a pressure manometer (8). The said plurality of
adjustable clamping members (10) and the said base (12) located at lower
part can be fitted anywhere in the said heavy-metal main stand (9).
All the said pressure manometer, teflon key, sheet / disc (8) are provided
in such a way that the said elements (8) can be removed and fitted in order to
achieve ease of maintenance and interchangeability. The bed-height for the
process for cyanide treatment of effluents using the said apparatus is variably
adjustable
Filters are constructed with an under drain system for collecting the treated
waste water and any biological solids that have detached from the media The
under drain system is both a collection unit and a porous structure through
which air can circulate. The said attached growth trickling filter is split up into
different zones including aerobic (1) and anaerobic zone (3).
Aerobic attached growth trickling filter process is usually used to remove
organic matter in waste water. The trickling filter consists of a bed of highly
permeable medium to which microorganisms are attached and through which
waste water is percolated or trickled. The filter media usually consists of either
rock, slag, or a variety of plastic packing materials. The size of rocks vanes
from 1 inch to 4 inches. The depth of rocks varies with each particular design
but usually ranges from 3 ft. to 8 ft Rock filter beds are usually circular and
the liquid waste water is distributed over the top of the bed by a rotary slot
machine
The organic material present in waste water is degraded by a population of
microorganisms attached to the filter media. Organic material from the liquid is
absorbed into the biological film or slime layer. In the outer portion of the
biological slime layer, the organic material is degraded by aerobic
microorganisms. As the microorganisms grow, the thickness of slime layer
increases, and the diffused oxygen is consumed before it can penetrate the
full depth of the slime layer. Thus an anaerobic environment is established
near the surface of the media. As the slime layer increases in thickness the
absorbed organic matter is metabolized before it can reach the

microorganisms near the media face. As a result of having no external organic
source available for cell carbon, the microorganisms near the media face
enter into an endogeneous phase of growth and lose their ability to cling to
the media surface. The liquid washes the slime off the media and a new slime
layer starts to grow In conventional trickling filter the hydraulic loading rate is
adjusted to maintain a slime layer of uniform thickness
Iron forms complex with cyanide (CN). It takes up cyanide when cyanide
level is high This helps moderate cyanide load on the system Cyanide above
a certain level of concentration is inhibitory to the biological treatment system
A transition zone (2) has thus been provided to form a buffer zone in order to
act as cyanide (CN) moderator.
Thiocyanate, SCN', is most effectively treated by anoxic microorganisms
Hence, the slag or stone media bed-height will be relatively higher in effluent
having higher thiocyanate. The plastic aerobic zone (1) bed-height will be
more when free CN is higher.
The process for cyanide treatment of effluents in a multi-zone multi-media
unit with attached growth trickling filter using the said apparatus includes the
process of controlled aeration. Suitable bed-height, as and when required, at
the said different zones (1, 2, 3) of the said apparatus for facilitating aerobic
process dunng the treatment of different forms of cyanide is maintained In
order to facilitate the said anaerobic biodegradation process condition during
the treatment of different forms of cyanide suitable bed-height, as and when
required, at different zones (1, 2, 3) is maintained. Hydraulic as well as
organic loadings are optimised at various load levels suiting the requirements
of the said process.
Fig 3 is a plot illustrating the effect of splitting up of the aerobic (1) and
anaerobic zones. (3) on the two different media, according to the present
invention. The CN reduction in different stages of the said apparatus is seen
from Fig. 3. The said aerobic zone (1) is on plastic media and the said
anaerobic zone (3) is on stone media. At the initial stage of the process the
cyanide (CN) concentration (mg/lit) in the effluent is high. The reduction of CN
follows as the waste water passes through the said aerobic (1), transition (2)
and final anaerobic (3) stages. Aeration in aerobic zone (1) is performed by
forced draft The growth of two types of the said biological smiles is
independent of each other.
The optimized value of the bed-height ratios is established at 22 1 ratio of
plastic, iron ore and stone chips respectively. This is indicated in the
accompanying Fig. 4. Different bed-heights are required in plastic, iron ore,
stone chips media. The bed-height at collection chamber is same as that of
the said stone-chip media.
Fig. 5 is a plot illustrating percentage cyanide (CN) reduction versus flow
rate Percentage CN reduction is calculated in terms of the ratio of the
percentage final CN and initial CN. Flow rate is measured in litres per second

Effect of optimised hydraulic / organic loading at vanous loads is seen from
the said Fig. 5
Depending upon the suitability of requirements of the said process, the
said media can be changed and proportions of each elements of the said
media can also be changed upon requirements of the said process
While the principles of this invention have been described in connection
with specific embodiment, it should be understood clearly that these
descriptions are made only by way of example and are not intended to limit
the scope of the invention.


We Claim:
1 An apparatus for cyanide treatment of effluents in a multi-zone multi-media
unit with attached growth trickling filter having a bed of highly permeable
medium to which microorganisms are attached to and through which waste
water is percolated or trickled characterized by that the apparatus has.
multi-zones (1, 2, 3) for facilitating aerobic process;
a multi-media filter consisting of variety of plastic packing materials, rock, iron
ore and stone slag as media,
a transition zone (2) to form a buffer zone (2) in order to act as cyanide (CN)
moderator,
a buffering zone (2) to reduce high cyanide (CN) spike that is inhibitory to the
biological treatment process,
a first tube (4) with provisions for fitting sheet / disc with holes in its upper part
for uniform distribution of liquid and the said tube (4) having provisions for
fitting sheet / disc with holes, cones, pressure manometer, teflon key and
other auxiliary attachments (8) in lower part;
a second (5) and third tube (6) with provisions for fitting sheet / disc with holes
in its upper part for uniform distribution of liquid and the said tubes (5, 6)
having provisions for fitting sheet / disc with holes, cones, pressure
manometer, teflon key and other auxiliary attachments (8) in lower part,
a fourth tube (7) with provisions for fitting teflon tap (8) in its lower part for
collection of drainage,
a heavy metal-stand (9) having a plurality of adjustable clamping members
(10),
an adjustable base (12) located at lower part of the apparatus, and
a platform (11) in upper part with the said stand to hold a tank / feed vessel
(13) of suitable capacity having a pressure manometer (8);
in which all the said pressure manometer, teflon key, sheet / disc and other
auxiliary attachments (8) are provided in such a way that the said elements
(8) can be removed and fitted in order to achieve ease of maintenance and
interchangeability and the bed-height for the process for cyanide treatment
of effluents using the said apparatus is variably adjustable
2 An apparatus for cyanide treatment of effluents, as claimed in claim 1,
wherein all the said four tubes (4, 5, 6, 7) are fitted vertically and means are
provided in order to achieve water proof / leak proof fittings during the said
apparatus's installation
3 An apparatus for cyanide treatment of effluents, as claimed in claim 1,
wherein the said plurality of clamping members (10) and the said base (12)
located at lower part can be fitted anywhere in the said heavy-metal main
stand (9).
4 An apparatus for cyanide treatment of effluents, as claimed in claim 1,
wherein the said attached growth trickling filter is split up into different zones
including aerobic (1) and anaerobic zone (3) in order to facilitate the process
for cyanide treatment of effluents

5 A process for cyanide treatment of effluents in a multi-zone multi-media unit
with attached growth trickling filter using the apparatus of claim 1 comprising
the steps of
(i) aerating of effluents in a controlled manner,
(ii) maintaining suitable bed-height at different zones (1, 2, 3) for facilitating
aerobic process during the treatment of different forms of cyanide;
(iii) maintaining suitable bed-height at different zones (1, 2, 3) for facilitating
anaerobic biodegradation process condition during the treatment of
different forms of cyanide, and
(iv) optimising hydraulic and organic loading, at various load levels
6 A process for cyanide treatment of effluents, as claimed in claim 5, wherein
said bed height at different zones is established using a particular ratio of
plastic, iron ore and stone.
7 A process for cyanide treatment of effluents, as claimed in claim 5, wherein
aeration in aerobic zone (1) is performed by forced draft.
8 A process for cyanide treatment of effluents, as claimed in claim 5, wherein
the said aerobic zone (1) is on plastic media and the said anaerobic zone (3)
is on stone media.
9 A process for cyanide treatment of effluents, as claimed in claim 5, wherein
growth of two types of biological smiles are independent of each other

ABSTRACT

An Apparatus and a Process for Cyanide Treatment of Effluents in a
Multi-Zone Multi-Media unit having attached Growth Trickling Filter
The present invention relates to an apparatus and a process utilizing the said
apparatus for cyanide treatment of effluents in a multi-zone (1, 2, 3) multi-
media unit with attached growth trickling filter having a bed of highly
permeable medium to which microorganisms are attached to and through
which waste water is percolated or trickled. The said apparatus includes (i)
multi-zones (1, 2,-3) for facilitating aerobic process, (n) multi-media filter, (iii) a
transition zone (2) to form a buffer zone (2) in order to act as cyanide (CN)
moderator and (iv) a buffering zone (2) to reduce high cyanide (CN) spike that
is inhibitory to the biological treatment process. Two different types of
biological slimes are formed under different process conditions The said
process ensures a proper process condition for aerobic and anaerobic
biodegradation The process is performed in such a manner that suitable bed-
height, as and when required, is achieved at different zones (1, 2, 3) for
facilitating both the aerobic and anaerobic biodegradation process condition
during the treatment of different forms of cyanide