|Title of Invention||
PROCESS OF WASTEWATER RENOVATION
|Abstract||PROCESS OF WASTEWATER RENOVATION|
|Full Text||FORM - 2
THE PATENTS ACT, 1970
(39 OF 1970)
(See Section 10)
TITLE OF INVENTION
"Process of Wastewater Renovation"
(a) INDIAN INSTITUTE OF TECHNOLOGY Bombay (b) having administrative office at Powai, Mumbai 400076, State of Maharashtra, India and (c) an autonomous educational Institute, and established in India under the Institutes of Technology Act 1961.
The following specification particularly describes the nature of the invention and the manner in which it is to be performed.
FIELD OF THE INVENTION
This invention relates to a process for treating wastewater in.a biofilter system consisting of soil, bacterial culture and geophagus earthworm Pheretima elongata, and optionally mineral additives. This system is referred as Soil Biotechnology
The demand for water has gone up and the need to renovate and reuse water has become imperative. In developing countries existing technologies for wastewater renovation are viable only in very large-scale operations and so cost of operation becomes prohibitive and lead to improper functioning and maintenance of plants [Arceivala, S. J., Wastewater Treatment for Pollution control, TMH publications New Delhi, India, 1998]. Even the treated water in many cases breed mosquitoes thereby compounding the problem.
Several technologies are available for treatment of wastewater containing COD, BOD, nitrogen, phosphorous, suspended solids, bacteria, color, odor etc. The presence of these pollutants in water is a form of toxicity and should therefore be substantially removed. Activated Sludge, Trickling filter, Oxidation Ponds are technologies currently in operation. All these technologies are energy intensive and viable only in very large scale. They produce residues whose disposal can create problems. Treated water is generally not fish compatible and such water discharged into drinking water sources endanger lives of dependent population [Bhawalkar, U.S., "Vermiculture Bioconversion of Organic Residues", Ph.D. Thesis, Dept. of Chemical Engineering, IIT Bombay, 1996; Pattanaik B.R., "Processing of Wastewaters in Soil Filters", ", Ph.D. Thesis, Dept. of Chemical Engineering, IIT Bombay, 2000]. Land treatment of wastewater has been known for long. Here intermittent hydraulic loading of 0.001 m3/m2.hr is permissible and treated water is not easy to recover for reuse. Root zone treatment technology is similar to land treatment methods and have similar requirement and features [Nivens, Jr.; Kirk, N, US Patent 6264838, "Onsite Wastewater"Recycling System"]. Constructed wetland treatment technology has been in practice in many areas. In this case wetland - rock - aquatic ecology is engaged wherein subsurface flow brings about treatment.
Hydraulic loading of 0.001-0.005 m3/m2.hr is observed [Behrends; Leslie, L; US Patent 5863433, "Reciprocating Subsurface Flow, Constructed wetland for improving Wastewater Treatment"].
Use of surface dwelling redworm Eisenia foetida in vermifilters is known [Lee, K. E., Earthworms - Their ecology and relationship with soils & land use, Academic Press, 1985]. As experienced there are problems of maintaining them in the filter. This is because they cannot live in their own excreta and as conditions arising from accumulation of waste products become adverse they migrate away. [Bhawalkar "Vermiculture Bioconversion of Organic Residues", Ph.D. Thesis, Dept. of Chemical Engineering, I IT Bombay, 1996.; Pattanaik B.R., "Processing of Wastewaters in Soil Filters", Ph.D. Thesis, Dept. of Chemical Engineering, IIT Bombay, 2000]
In general, available technologies do not use soil system because they tend to choke and become non-functional.
OBJECT OF THE INVENTION
The basic objective of the present invention is thus directed to providing a process and a system for large scale processing of waste waters using green technologies without formation of objectionable process wastes and eliminating common operating problems of clogging and interruptions.
Another object of the invention is to provide process for wastewater renovation - an integrated process combining Geophagous earthworms with potent bacterial cultures, minerals, organics of wastewater and soil.
Another object of the invention is to provide a process with high oxygen transfer rates so as to ensure aerobic environment and have high removal of BOD, COD and NH4-N and pathogens.
Yet another object of the invention is to provide a process for easy removal of suspended solids without use of energy and to recover these solids as good quality fertilizer.
Yet another object of invention is to provide a process wherein bacterial selection interaction is nurtured via earthworm culture so as to obtain a stable system despite large variation in input load.
Yet another object of the invention is to provide an engineered system for removal of nitrates and phosphates in water.
Yet another object is to provide a process for renovation at higher hydraulic loading rates.
Yet another object of the invention is to provide Biotower technology using the SBT system and save on space wherein very high removal efficiencies are achieved.
Yet another object of the invention is to provide a technology for non-chemical cleaning of swimming pool waters.
Yet another object of the invention is to provide a process for renovation of wastewater to fish compatible quality so that water bodies viz as lakes and rivers afflicted by pollution can be restored to health.
Yet another objective of the invention is to provide for a process of wastewater management that can be easily set up and run with minimum cost, operational constraints and with maximal operational advantages.
Yet another object of the invention is to provide a new technology for wastewater renovation wherein bacteria, color and odor are removed in the system without use of toxic chemicals.
Yet another object of the invention is to provide a technology for renovation of non¬toxic wastewater from industrial processes.
Yet another object of the invention is to provide a process technology for wastewater renovation, which could be engaged in either batch or continuous modes so as to cater to both small and large-scale requirements.
Yet another object of this invention is to provide a technology for changing over from existing conventional wastewater treatment plants which are not being run due to high costs and residue disposal problems.
It has now been surprisingly found by way of the present invention that effective wastewater renovation can be achieved by way of conversion of waste in the water to environmentally friendly products when such conversion is carried out selectively in the presence of cultures of geophagus earthworms Pheretima elongata in combination with bacterial cultures, selective minerals and soil.
BRIEF DESCRIPTION OF INVENTION
Thus according to one aspect of the invention there is provided a process for treating waste water for providing substantially non-toxic reusable water comprising :processing the wastewater in a biofilter media comprising culture of geophagus earthworms Pheretima elongata, soil and bacterial cultures such as hereindefined with or without other mineral additives to thereby provide substantially non-toxic reusable water.
According to another aspect of the invention there is provided a biofiltration system for carrying out the process of treating wastewater to provide substantially non-toxic reusable water comprising:
a) biofilter media comprising one or more filter media selectively comprising of anyone or more of culture of geophagus earthworm, bacterial cultures, soil with or without mineral additives;
b) Means to process wastewater therethrough said biofilter means in one stage or multiple stages and collect/supply the water thus processed substantially free of toxic content.
According to another aspect of the invention there is provided a process for producing biofilter media comprising earthworm culture comprising:
a) collecting the geophagus earthworm Pheretima eiongata from its natural
b) developing a covered environment comprising plants with tap roots, and/or
adventitious roots on the soil by providing 20-30 g/m2 day organics such as
herein defined, ii) maintaining moisture at about 30-40% iii) addition of the
preferred mineral powder less than 1000 micron @ 5-10 g/m2 day, c) harvesting
the culture after monsoon as sieved powder less than 500 micron to use the
powder obtained as a source of earthworm culture.
According to yet further aspect there is provided a process for producing biofilter media comprising bacterial culture comprising:
a) developing the appropriate geophagus earthworm culture Pheretima eiongata in in 4-6 weeks by providing i) 20-30 g/m2 day organics such as herein defined ii) moisture about 30-40% iii) preferred mineral powder less than 1000 micron @ 5-10 g/m2 day.
b) maintaining the mix above under conditions for developing the cultures and harvesting the culture as a sieved powder less than 500u for use as source bacterial culture.
In accordance with the general process of this invention, the single stage process basically involves:
i) Preparation of the geophagus earthworms culture Pheretima eiongata and
preparation of bacterial culture ii) Preparation of the soil media to contain the geophagus earthworms
Pheretima eiongata and bacterial culture iii) Construction of the under drain and the collection tank system iv) Layering of the media over the under-drain system v) Percolation of the waste water through the layered media vi) Collection of the treated water in the collection tank vii) Recirculation of the treated water to achieve the desired quality viii) Using bioindicators to monitor the treated water at various stages of the
In one of the aspect of the invention mineral additives such as primary mineral powder / weathered mineral powder/ iron rich mineral powder of specified particle sizes and composition are added into the wastewater to be treated.
In another aspect of the invention, a multi stage process of wastewater renovation is carried out in a bio-tower wherein several single stage SBT processes are sequentially integrated.
In another aspect of the invention, a multi stage process of the wastewater renovation is carried out in a bio tower wherein several single SBT processes are integrated with the option to re-circulate the treated water from any stage to any other stage as desired.
In another aspect of this invention the SBT process may be implemented in any existing conventional activated sludge plants and their like.
In another aspect of this invention the SBT process may be implemented in any existing conventional oxidation ponds and their like.
The process described herein removes one or more of pollutants viz. BOD, COD, ammonium nitrogen, nitrate nitrogen, suspended solids, phosphate, odor, colour, bacteria while substantially increasing dissolved oxygen and producing fish compatible renovated water and all this in a single integrated bed without producing sludge.
DETAILED DESCRIPTION OF INVENTION
An appropriate geophagus earthworm culture Pheretima elongataus engaged. The said culture is developed in an environment comprising plants with t§p-foots\ and/or adventitious roots space by providing 20-30 gm/m2.d organics such as wild ruminant animal dung which contains potent bacterial culture, straw and leaf litter, moisture 30-40 percent and preferred mineral powder less than 1000 n size @ 5-10 g/m2.d. This culture is harvested for use as source culture of earthworms and desired bacteria.
An appropriate formulated soil media 0.3-0.4m thick produced by combining animal dung (15 - 50%), preferred mineral powder of particle size 500 -1000 \x (50 - 85%), bacterial and earthworm culture 1 percent all processed in an environment comprising plants with tap roots, and/or adventitious roots for 7 days by maintaining 30-40% moisture.
Preferred mineral powder from natural sources containing silica (25-30 % Si),
alumina (6-8 % Al), iron (1-6 % Fe), Potassium (2 -8 %), Calcium (2-10 %),
Magnesium (1-3 %) Phosphorous (0.003- 0.1%) and also containing micronutrients.
Suitable Provision for distribution of wastewater. By providing piped delivery to all
parts of filter and distribution partsto deliver water uniformly.
An underdrain of large boulders 0.3-0.4m thick, 1/100 - 1/500 sloping floor and a
collection tank at a suitable location.
Process control is achieved by adjusting loading rates, addition of mineral powder so
as to eliminate bioindicators of abnormality viz., mosquitoes, rats, odor, plant disease
This approach brings about purification of wastewater dependent on the process time, organic and hydraulic load.
In another embodiment of the invention mineral additives powder are added to facilitate renovation.
In another embodiment of the invention biotower SBT for the renovation of wastewater is achieved where in the process is carried out in stages with each stage typically 0.30-0.35m with the media in the biotower. A contraption of the system involves upto 10 stages with each stage having a free board of 1.8 -2.0m to maintain and also to carry out routine operation.
In another embodiment of the invention the treated waste water from any one of the stages in the bio tower may be re-circulated to any other stage to achieve selective denitrification by contacting the treated water with the layered stage that contains higher amounts of BOD/COD.
When soil systems are used for waster water renovation, the system tends to choke. The role of the earthworm - bacterial culture is to ensure uninterrupted operation. This is reflected in the high, values of rate constants for the different solutes BOD, COD, Ammonium Nitrogen, Nitrate Nitrogen, Suspended solids, Color, Odor, bacteria (Pattanaik, 2000) to be removed as described in the examples. The invention is now described and illustrated with non-limiting examples.
Fig. 1 shows a schematic of the system employed. A wastewater treatment plant 25.0m x 10.0m x 1.0m below ground was constructed. A slope of 1/100 was provided on the bottom surface of the filter. The bottom surface was made impervious. A tank for collection of renovated water was suitably provided. The filter fillings consisted of 300 - 400 mm layer of formulated earthworm Pheretima elongata soil media and 0.3 - 0.4m under drain of stone rubble of sizes varying from 200mm to 2 mm. The performance of filter operated in batch mode is given in Table 1. Hydraulic loading of 0.02-0.06 m3/m2.hr has been observed. Table 2 shows the results of continuous operation. Biofilter filling details are given in Fig.2. BOD, COD, NH4-N, N03-N, phosphate (without using additives), suspended solids, color, odor, bacteria removal can be achieved. Dissolved oxygen improves significantly due to renovation. Fish inoculated in the filtrate collection tank showed no fatality during operation and storage of treated water, indicating fish compatible water is produced. Redox potential of water improves substantially from 50mV to 800mV indicating aerobic environment and pathogen destruction.
Table 1: Batch Biofilteration results for Pheretima elongata cultured Soil filters
Experimental conditions: Vb = 84.0m3;Vr= 10m3/hr; Vf = 0.0 ; V1 = 30m3 .batch Time = 4 hr
The typical values for the inlet (initial) and outlet (final) wastewater are shown in Table 1 & 2. Variations in input do take place, but the desirable output water quality is always obtained by adjusting the process operating conditions.
It is relevant to note that good phosphate removal is observed without using additives. Wherever higher removal is needed various additives viz. Lime, ferric sulfate can be used to reduce the phosphates to desired levels.
The operation of this system under batch and continuous modes reveals that earthworm culture Pheretima elongata ensures clogging free operation, reproducible media reactivity and absence of abnormal bioindicators and water out put parameters indicating excellent water quality. No fish fatality during the operation is a unique feature of the process.
Table 2: Continuous Biofilteration results for Pheretima elongata cultured Soil filter
Vb - 84.0m3; Vr= 2.4m3/hr; Vf = 5.0m3/h;
A schematic of a biotower is shown in Fig.3. The results of the use of the biotower for wastewater renovation are given in Table 3. A Biotower is constructed using 6 vessels of 30.0L each mounted on a frame vertically one above the other. Each vessel contains the SBT media.
In a typical experiment carbonaceous substrate (glucose / sucrose) is charged form the top of the biotower at a predetermined flow rate. The outlet at the bottom of the filter is collected and analyzed for COD. ORP probes were inserted all along the tower profile and probe response was recorded in data acquisition system.
The results show that very high efficiency removal of COD can be achieved. However the overall rate of COD removal for simple molecule (BOD) could be 0.3-0.5 kg/m3.d. The reactivity of the bed and earthworm activity all along the depth found to be uniform. In view of the multiple stages the water quality parameters (BOD, COD, Nitrogen, suspended Solids, color, odor, bacteria, virus) as required can be achieved.
Table 3: Results of Biotower studies using 6 stage Pheretima cultured biotower
In these experiments mineral powder is contacted with the liquid substrate containing the pollutant (natural & synthetic) in conical flask. The flask is mounted on shaker incubator to facilitate solid - liquid contact typically for 30min. The temperature is maintained at 28 - 30C. The pollutant level in the liquid is determined by filtering off the solids from the sample reaction mixture. Results of sewage water contacted with additives are given below. Table 4 shows the effect of additives in wastewater renovation. The results show that use of mineral powder in the range 250 mg/L brings about substantial removal of pollution level in the wastewater.
Table 4: Effect of additives for COD and nitrate removal
*: Mineral powder containing silica ( 20 - 30% Si), alumina (6 - 8% Al), iron (1 - 6% Fe), Potassium (2 - 8% K),calcium(2-10 %),Mg (1-3 %)
Analytical Methods engaged for the analysis of COD, BOD, Ammonium Nitrogen, suspended solids, Color have been adopted from "Standard Methods for examination of Water and Wastewater", American Public Health Association, 18th
edition, Washington, 1992; Manual for Photometer SQ 118, E- Merck (Germany) 1997; Standard Methods of Water Analysis Handbook, Hach, USA (1997).
Bioindicators such as fish, mosquito, rats and flies have been identified visually and reported as our visual observation.
Bioindicators as a tool for assessment of pollution index of environment has been adopted from "Aquatic Chemistry" by Stumm, Werner; Morgan, J. J.; Aquatic Chemistry - an introduction emphasizing equilibrium in natural waters, 2nd edition, Wiley Interscience, NY, 1981.
Tests for microbiological indicators like Coliform organisms, Streptococci, Staphylococci, Kleibsella pneumonie, Salmonella, Shigella, Entamoeba hystolytica, Polio virus, Hepatitis virus were carried out using methodology from "APHA, 1992".
The advantages of SBT process are 1) land area saving can be designed 2) process engages local land resources 3) energy consumption is low as natural methods of oxygen supply is engaged 4) produces no residues for disposal which is a major issue in most waste water treatment plants. 5) very stable against load variations and 6) it is a green technology.
The unique features of this green technology are that the BOD, COD, ammonium nitrogen, nitrate nitrogen, suspended solid, colour, odour, bacteria, sufficient increase in dissolved oxygen, no residues for disposal are all made possible in a single tank constructed in the ground with its top open to atmosphere. In addition use of SBT achieves space saving, high removal efficiency, engages material that occurs locally, consumes no power for oxygen delivery to the system, leaves no residues for disposal and is very stable against shock loading. These advantages are unmatched by any known technology. ""
1. A process for treating waste water and contaminated water in a multilayered bioreactor wherein the water is processed through layers of
• biological media comprising of ruminant animal dung, primary mineral powder, bacterial and earth worm culture to purify water , remove color, odor, bacteria, suspended solids, and dissolved solids
• bacterial culture from ruminants preferably feeding on cellulosic materials organisms to process organics,
• geophagus earthworm Pheretima elongata to keep the bed active by regulation of bacterial population
• underdrain media comprising of four layers of varying thickness and
With or without mineral additives in single or multi stages in batch or continuous modes or their combinations in single or plurality of bioreactors to obtain substantially non toxic reusable water.
2. A process for treating waste water and contaminated water as claimed in
claimsl, wherein the underdrain media comprise
• a lowermost layer of a first layer of 250 mm thicknesss with particles of 100 - 200 mm;
• a second layer above the first layer of 100 mm thickness comprising of particles of 50 - 25 mm,
• a third layer above the second layer of 100 mm thick comprising of particles of 5 -10 mm and
• a fourth layer above the third layer of 5-10 mm comprising particles of 2 - 3 mm.
3. A process for treating waste water and contaminated water as claimed in claims
1-2 wherein the said biological media is prepared by mixing
• ruminant animal dung selected from cow, bullock, buffalo, goat, sheep in proportion of 15 - 50 %,
• primary mineral powder of particle size 500 -1000 microns in proportion of 50 -75% and
• bacterial and earthworm culture 1 %
processed for 7-10 days at 30 - 40 % moisture.
4. A process for treating wastewater and contaminated water as claimed in claims 1-3 wherein the said bacterial culture is obtained from excreta of ruminants selected from cow, bullock, buffalo, goat, sheep preferably fed on cellulose based feed.
5. A process for treating waste water and contaminated water as claimed in claim 1-4, wherein the cultures of geophagus worm Pheretima elongata is grown in an environment comprising plants with tap roots, and/or adventitious roots or surface root system in the presence of about 20-30 gm/m2/day of organics such as excreta of ruminants preferably feeding on cellulosic materials, minerals of particle sizes 6. A process for treating waste water and contaminated water as claimed in claims 1-5 wherein the mineral and mineral additive source is minerals comprising silica (25-30% Si), alumina (6 - 8 % Al), iron (1 - 6 % Fe), calcium (2-10 %), magnesium (1-3 % Mg), potassium (2-8 % K), phosphorous (0.003- 0.1% P) and micro nutrients zinc and molybdenum.
7. A process for treating wastewater and contaminated water as claimed in claims 1-6 wherein hydraulic loading is upto 0.2 cum/sqm.hr, organic loading up to 0.2 kg/sqm.day to obtain reusable water.
8. A process for treating wastewater and contaminated water as claimed in claims 1-7 wherein the output of single stage purification is fed into second stage or plurality of stages in batch, continuous or their combinations to obtain reusable water.
9. A process for treating wastewater and contaminated water as claimed in claims 1-8 adapted to large variations in input hydraulic load is up to 0.2 cum/m2h.
10. A process for treating wastewater and contaminated water as claimed in claims1-9 wherein process is operated in conjunction with exiting wastewater & contaminated water treatment operation.
|Indian Patent Application Number||383/MUM/2002|
|PG Journal Number||20/2007|
|Date of Filing||26-Apr-2002|
|Name of Patentee||INDIAN INSTITUTE OF TECHNOLOGY, BOMABY|
|Applicant Address||HAVING ADMINISTRATIVE OFFICE AT POWAI, MUMBAI - 400 076, STATE OF MAHARASHTRA, INDIA, AN AUTONOMOUS EDUCATIONAL INSITUTE, AND ESTABLISHED IN INDIA UNDER THE INSTITUTE OF TECHNOLOGY ACT 1961.|
|PCT International Classification Number||N/A|
|PCT International Application Number||N/A|
|PCT International Filing date|