FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
& THE PATENTS RULES, 2003
COMPLETE SPECIFICATION (See section 10; rule 13)
1. TITLE OF THE INVENTION:
BIO-FILTER MEDIA AND USE THEREOF FOR EFFLUENT TREATMENT
2. APPLICANT(S)
(i) (a) NAME: Transpek Industry Ltd.
(b) NATIONALITY. Indian Company
(c) ADDRESS: 6th Floor, Marble Arch, Race Course Gircle, Vadodora 390 007, Gujarat, India.
(ii) (a) NAME: Transchem Agritech Pvt. Ltd.
(b) NATIONALITY: Indian Company
(c) ADDRESS: 850/2, Makarpura GIDC, Vadodara - 390010, Gujarat, India.
PREAMBLE TO THE DESCRIPTION:
The following complete specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION:
This invention relates to bio-filter media and use thereof for effluent treatment. More particularly, present invention relates to bio-filter media, process for preparation thereof and use of said media for treatment of effluent. Biological treatment of waste water is assigned IPC symbol C02F3/00. The invention involves aerobic process which is assigned symbol C02F3/02.
BACKGROUND AND PRIOR ART
Bio-filters comprising components including woodchips and earthworms for treatment of effluents are known in the art.
An invention disclosed in CN101671081 relates to a method for using a layered earthworm bio-filter to treat domestic sewage, said bio-filter consists of a plurality of plastic modules which are filled with a filtering material consisting of wood chips and matrix containing earthworm. However, it has a drawback that there is a long stabilization period before which the system can be effectively used.
Closest prior art is disclosed in EP1887078. The system employed in said prior art is comprising of various layers: the first layer involves earthworm humus mixed with a celluloid material such as saw dust, wood shaving etc. Second layer is made up of celluloid material. Micro-organisms produced in earthworm humus (i.e., 1st layer) and earthworms inhabit together in the 2nd layer. A third layer comprising a substantially inert material making a porous bed underlying the second layer. The bacteria inoculation medium is the second layer of the system, which is made up of celluloid material that can be sawdust or wood shaving. The thickness of this celluloid

material is 70 cm deep, in which micro organisms produced by the earthworms' humus and earthworms inhabit together.
The invention disclosed in abovementioned prior art EP1887078 has disadvantages that it requires higher retention time compared to present invention. Moreover, the system disclosed in EP 1887078 is less favorable for earthworms to multiply compared to that of present invention.
There is a need for a process for effluent treatment which is efficient and which reduces stabilization period of the system.
OBJECTS OF INVENTION
It is an object of invention to provide pre-treated bio-filter media to be used in a system for effluent treatment;
Another object of invention is to provide a method of preparation of said bio-filter media;
Another object of invention is to provide a process for effluent treatment using said pre-treated bio-filter media;
Another object of invention is to provide a process for effluent treatment which reduces stabilization period of the system;
Another object of invention is to provide conducive environment to earthworms during the process and thereby further improve efficiency of the system;
Another object of invention is to provide a process that results in reduced chemical oxygen demand (COD) of the treated water;

Yet another object of invention is to provide a process for treatment of sewage water, dairy effluent and effluent from food-processing industry which converts them into treated water rich in plant nutrients and suitable for irrigation;
Yet another object of invention is to provide process for treatment of effluent, wherein the resulting treated water does not contain objectionable level of pathogenic microorganisms.
Yet another object of invention is to provide process for treatment of industrial effluent so that the treated effluent can be discharged.
Yet another object of invention is to provide process for treatment of effluent which does not produce undesirable sludge.
Yet another object of invention is to provide a process for treatment of effluent wherein increased earthworm population and compost are by-products.
Yet another object of invention is to further increase efficiency of the system by inducing vibrations.
DETAILED DESCRIPTION OF INVENTION
An efficient process has been developed for conversion of sewage, dairy and distillery effluents into nutrient-rich water suitable for irrigation. Using the invented process, effluent from fabric printing units and industrial effluents can also be treated to reduce chemical oxygen demand so that they can be discharged.
Inventors of present invention have developed a modified system and a process wherein a pre-treated media is used which eliminates or

shortens the stabilization period of the system. Further, the system results in enhanced efficiency and it provides conducive environment to earthworms.
The process employs a system comprising two main layers.
Composition of layers:
First or top layer is composed of pre-treated agricultural waste such as shredded cotton waste, wood chips, plant-based particles of larger as well as smaller size etc., or a mixture thereof. The components of first layer are subjected to pre-treatment (described in detail later in this specification), resulting into "treated bio-filter media" which also contains microorganisms which are acclimatized to survive in the system and play role in decomposition of pollutants present in the effluent. Earthworms along with earthworm humus are added on the top of first layer.
The first layer is optionally divided into sub-layers of average depth 0.15 to 0.3 meters.
Second layer is necessarily an inert layer composed of stones, pebbles of various size.
The composition of layers and size thereof is crucial for an efficient and effective system. It determines the quality of output as well as the flow rate or retention time of the effluent within the system and thus it determines efficiency and effectiveness of the system.
Earthworms which are present in first layer play an important role in enhancing the process of bio-conversion in several ways. They reduce BOD, COD, suspended solids, dissolved substances etc. from

waste water. In addition to this, they improve permeability and aeration which facilitates maintenance of aerobic conditions. Thus, earthworms improve effectiveness of the system in terms of filtration and aerobic conversion. Moreover, suspended solids get trapped on the top of first layer and are processed by earthworms which convert suspended solids into food for microorganisms. Microorganisms in turn aerobically convert it into material which can be used as compost.
First layer provides a medium for microorganisms to grow and it also facilitates filtration & percolation of effluent downwards. The inventors of present invention have concluded that the composition of this layer is very crucial for good efficiency and effectiveness of the system. This layer should be suitable to carry out all abovementioned functions effectively.
As mentioned earlier, second layer is necessarily inert layer composed of stones, pebbles of various size.
Abovementioned layers are confined within a structure or compartmentalized modular system made up of a suitable material such as cement or plastic/polymer. A set of perforated plastic trays/crates filled with the bio-filter media can be arranged to form layers mentioned above. The material of the structure mentioned herein is only illustrative and not limitative to the scope of the invention.
The system involves a means for aeration. It may be conventionally used perforated pipes or the structure itself may be perforated.

The system may include a means for inducing vibrations to ensure that effluent flow is not channelized and there is even distribution thereof, thereby increasing the surface area of the bio-filter media with which the effluent comes into contact. This increases overall efficiency of the system and makes it possible to increase flow-rate of the effluent through the system without compromising quality of out-flow i.e., treated water.
Untreated sewage water or effluent has undesirable properties which make it unfit for irrigation purpose. For instance, it has 0.05-0.08% suspended solids, COD in the range of 300-500 ppm and BOD in the range of 150-250 ppm, dark grey colour and strong odour. It also contains pathogenic microorganisms such as fecal coli form as many as>106.
Effluent to be treated is sprinkled on the top layer of the system and is allowed to percolate through layers of the system.
After treatment in the invented system, the out-put or treated water has reduced BOD & COD, clear to pale yellow colour, reduced odour, and reduction in fecal coli form from 106 to 103. Fish can easily inhabit in treated water. It also meets the requirements for irrigation purpose.
The process also converts ammonia and some ammonium compounds into nitrates through the process of nitrification by microorganisms present in the system. Initially 25-50 ppm of ammonia is present in the effluent to be treated, which gets reduced to <10 ppm after treatment by the invented process.

Phosphorus compounds get converted into soluble phosphate form. Thus the invented process improves bio-availability of nutrients to plants.
Invented process can be used for treatment of industrial effluents whereby the treated effluents can be safely discharged.
Preparation of bio-filter media to be used as first layer
[pre-treatment of media]:
The agri-waste media used for making first layer as mentioned above contains lignin, tannins and resin like compounds. If the media is used without pre-treatment, it not only imparts undesirable colour and odour to the treated effluent, but it also results in increased COD of the outflow for an initial period which is called "stabilization period" of the system. Pre-treatment of the media helps in eliminating or reducing the stabilization period of the system and makes it ready to use.
Agri-waste such as saw-dust, wood chips, shredded cotton and subabul stalk etc. can be treated as explained herein, and used as media (to be loaded as the first layer) for the purpose of present invention.
The organic impurities are removed by leaching out by washing. If sewage water is used for leaching, it also adds nutrients essential for growth of micro-organisms which play a role in bio-degradation. It takes 10-15 days to leach out significant quantity of organic impurities.

After removal of significant proportion of organic impurities from the media, a consortia of bacterial culture comprising nitrifying and phosphate solubilizing bacteria which may include Rhizobium, Azotobacter, Bacillus, Nitrosomonas, Nitrobacter, Pseudomonas, Trichoderma etc. or a mixture thereof, is added to the media and mixed with it.
All biological material used for the purpose of invention was obtained from Gujarat, India.
As per an embodiment, 8320 kg of shredded cotton waste of the particle size ranging from 15-25 mm was taken in a container with a capacity of 10 mts x 10 mts, and 1.5 mts deep [150 m3]. 28,000 liters of sewage water was passed through it over a period of 15 days. >70% reduction in COD was achieved in 15 days. [This period could be reduced by increasing the quantity and flow rate of sewage water. It also depends on type of media used and contents thereof]. Bacterial culture comprising Azotobacter, Rhizobium, Nitromonas and Pseudomonas was added to the media.
The mixture thus prepared was used as the first layer in the effluent treatment system.
EXAMPLE-1
Treatment of effluent from fabric printing unit
An effluent treatment system comprising two main layers was employed for treatment of effluent from fabric printing unit containing dye. First layer was divided into five sub-layers. Each sub-layer was formed by arranging a set of perforated plastic trays of

dimensions 0.6x0.4x0.15 (height) meters covering total area of approximately 80-82 sq.mt. Five sub-layers were similarly formed by arranging sets of plastic trays one above the other. Each tray was filled with pre-treated media which was prepared as explained above. Earthworm-humus and earthworms were added on the top of the first layer. Subsequently, earthworms spread in all 5 sub-layers. The sub-layers were 0.05 mts apart, owing to thickness of base of perforated plastic trays. Second layer was formed by arranging set of plastic trays filled with inert media comprising grit, stones and pebbles of various size and kept below first layer. Effluent from fabric printing unit was sprinkled on the top of the first layer of the system at a rate of 500 lit/sq.mt/day. The results of this experiment are presented in Table-1. It is compared with "control" in which the experiment was conducted in same manner except that the bio-filter media was not pre-treated.
Table-1

Treatment of effluent from fabric printing unit
Days Pre-treated bio-filter media used Bio-filter media used without pre-treatment
COD
of
inlet COD
of
outlet %
Reduction in COD COD of inlet COD
of
outlet %
Reduction in COD
1 624 231 63 624 476 24
2 606 242 60 606 375 38

3
660 271 59 660 389 41
5 588 153 74 588 302 48
8 627 81 87 627 341 45
9 711 128 82 711 342 52
10 666 100 85 666 313 53
11 632 101 84 632 334 47
12 739 103 86 739 428 42
13 395 59 85 395 217 46
EXAMPLE-2
Treatment of effluent from Dairy unit
The process described in Example-1 was repeated for treatment of effluent from dairy unit, except that the area of each sub-layer was 20 sq.mt., and the flow rate of influent was 300 lit/sq.mt/day. The results are presented in Table-2. It can be seen from the results that when pre-treated bio-filter media was used, the system was stabilized quickly and within 3 days, 94% reduction in COD was achieved. On the other hand, when bio-filter media was not given pre-treatment, it took 12 days to achieve same level of percentage reduction in COD.

Table-2

Treatment of effluent from Dairy unit
Days Pre-treated bio-filter media used Bio-filter media used without pre-treatment
COD of inlet COD
of outlet %
Reduction
in COD COD of inlet COD of outlet % Reduction in COD
1 3000 620 79 3000 1500 50
2 3500 557 84 3500 1645 53
3 4822 307 94 4822 2169 55
4 3726 698 81 3726 1565 58
6 4018 187 95.3 4018 1607 60
7 3800 216 94;3 3800 1520 60
8 3136 193 94 3136 .1003.5 68
9 3600 196 94.5 3600 900 75
10 3000 183 94 3000 600 80
11 2900 160 94.5 2900 400 86.2
15 3100 150 95 3100 200 93.5

EXAMPLE-3
Treatment of sewage water with and without inducing vibrations
The process described in Example-1 was repeated for treatment of sewage water, except that pre-treated media was used in test as well as control, the area of each sub-layer was 20 sq.mt., and the flow rate of influent was 5000 lit/sq.mt/day. Further, in the "test" setup, vibrations were induced to ensure that effluent-flow through the media is not channelized and the effluent maintains uniform contact with the treatment media. The results are presented in Table-3. It can be seen from the results that the set up in which vibrations were induced, there is enhancement in efficiency which is reflected by increase in percentage reduction in COD of the outlet compared to that of control.
Table-3

Treatment of sewage water
Days Vibrations not induced in
the system
(Control/reference) Vibrations induced in the system
(Test)
COD of inlet COD
of outlet %
Reduction
in COD COD of inlet COD
of outlet % Reduction in COD
1 257 94 63.42 257 80 68.7
3 472 72 84.74 472 60 87.29
5 232 72 68.96 232 56 75.9

6
226 73 67.69 226 60 73.45
10 293 114 61.09 293 65 77.82
12 230 60 73.91 230 33 85.65
13 185 44 76.21 185 28 84.86
15 414.5 77 81.42 414.5 65 84.31
EXAMPLE-4
Treatment of sewage water:
Two sets of experiments were carried out in an effluent treatment system as described in Example-1. In Set-I, first layer of said system was not divided into sub-layers. In Set-II, first layer was divided into five sub-layers. Flow rate was maintained between 500-550 lit./sq.mt./day in both sets. Results are presented in Table-4. It can be seen from the results that % reduction in COD was better in Set-II in which the first layer was divided into five sub-layers.
Table-4

First layer not divided into sub-layers [Set-I] First layer divided into five sub-layers [Set-II]
COD
of
inlet COD
of outlet %
Reduction
in COD COD
of inlet COD
of outlet %
Reduction
in COD
1 410 72 82.4 410 37 91

2
265 48 81.8 265 19 93
3 328 67 79.57 328 26.24 92
4 304 82 73.03 304 45.6 85
Treated water was rich in plant nutrients, free from objectionable level of pathogenic microorganisms and suitable for irrigation which can be seen from results presented in' Table-5.
Table-5

Parameters Concentration before treatment Concentration after treatment
Ammoniacal nitrogen 36 ppm 2.5 ppm
Nitrates .11 ppm 43 ppm
Total Phosphorus 3.9 ppm 1.6 ppm
Available Phosphorus 0.9 ppm 6.2 ppm
Potassium 18.4 ppm 20.8 ppm
Fecal coliform >1600/100ml 240/100ml
BOD 210 20
Bioassay test: 100% survival offish after 96 hours in treated Biofilter outlet.

CLAIMS
1. A process for preparation of bio-filter media to be used in an effluent treatment system, said process comprising steps of: (1) taking agri-waste in a container; (2) leaching out organic impurities from said agri-waste by passing aqueous fluid through it; and (3) adding and mixing with the agri-waste a consortia of microbial culture.
2. A process as claimed in claim 1, wherein said agri-waste includes saw-dust, wood chips, shredded cotton and subabul stalk, or a mixture thereof.
3. A process as claimed in claim 1, wherein said microbial culture comprising micro-organisms selected from the group of Rhizobium, Azotobacter, Bacillus, Nitrosomonas, Pseudomonas, Nitrobacter, Trichoderma and Paecilomyces, or a mixture thereof.
4. Bio-filter media prepared in accordance with the process claimed in any of the claims 1-3.
5. An effluent treatment system comprising two main layers contained within a structure, first top layer is composed of bio-filter media as claimed in claim 4 along with earthworms and earthworm humus added to it; second layer is composed of stones, pebbles of various size and sand.

6. An effluent treatment system as claimed in claim 5, wherein the first main layer is divided into sub-layers, each sub-layer having an average depth of 0.15-0.3 meters.
7. An effluent treatment system as claimed in any of the claims 5 or 6, which has a means for aeration.
8. An effluent treatment system as claimed in any of the claims 5 - 7, which has a means for inducing vibrations in the layers of the system.
9. A process for effluent treatment comprising steps of: (1) sprinkling effluent to be treated on the* top layer of the effluent treatment system as claimed in any of the claims 5-8; (2) allowing the effluent to percolate through the layers of said system.