How 24/7 Water Supply Possible in India | TECHNICAL TALK

IPHE Auditorium, March 10, 2025

The Institution of Public Health Engineers, India (IPHE) marked Public Health Engineers Day by hosting a Technical Talk at its Salt Lake auditorium. The event gathered experts and professionals to discuss the latest developments and challenges in public health engineering.

Sri Tanay Kumar Das, former Chief Engineer (Civil), Northern Zone, PHE Directorate, West Bengal, delivered the keynote, sharing insights on sustainable water management, sanitation, and infrastructure development.

The session highlighted the need for innovation and stronger public health systems, reinforcing IPHE’s role in promoting knowledge-sharing and professional growth in the sector.

IPHE Council 2020-21

 

NEWS & MESSAGE OF CONDOLENCE – SAD DEMISE OF PROF. S J ARCEIVALA

We the members of Institution of Public Health Engineers, India are shocked and deeply aggrieved to receive the news of passing away of Prof. S J Arceivala, a great & respected personality in the profession of Public Health & Environmental Engineering.

Let his soul rest in peace.

We have no word to express our grief that we can convey to Professor’s family – it is so deep and touching to all of us.


S K Neogi
Secretary General
Institution of Public Health Engineers, India

Extra-Ordinary Annual General Meeting of IPHE

From: S K Neogi, Secretary General, IPHE, India
To: All Corporate Members of IPHE, India

Sub: Notice for the Extra-Ordinary Annual General Meeting of IPHE

Dear Member,

Kindly recall that The Extra-Ordinary General Meeting of the Institution convened and held on 26th February, 2017 was adjourned sine die. the adjourned meeting will now be held at 12:30 PM on Saturday, the 19th November, 2017 in IPHE Building at CK-58, Salt Lake, Kolkata - 700091.

The Agenda for transaction in the adjourned meeting shall be the same as those for the original meeting which are reproduced below:

Agenda

1) To consider and approve Amendment of Constitution of the Institution. The draft proposals for Amendment of the Constitution approved by the Council in its meeting held on 12th September, 2016 may be seen in the Institution website: www.ipheindia.com.
2) Miscellaneous

Annual General Meeting of IPHE 2016-2017

From: S K Neogi, Secretary General, IPHE, India
To: All Corporate Members of IPHE, India

Sub: Notice for the Annual General Meeting of IPHE 2016-2017

Dear Member,

The Annual General Meeting (2016-2017) of IPHE will be held at IPHE Bldg, CK-58, Salt Lake, Kolkata-700091 on Sunday, the 19th November, 2017 at 10:00 M to transact the following Agenda. You are cordially invited to attend the Meeting.

Agenda

1) Confirmation of the Minutes of the last AGM held on 20th November, 2016.
2) Presentation of the Annual Report by the Secretary General followed by discussion and adoption.
3) Presentation of Financial Report for the year 2016-17 by the Treasurer, proposal for appointment of Auditor for the year 2017-18 and fixing up of their remuneration.
4) Discussion on Financial Report and acceptance of the Audited Accounts including appointment of Auditor(s) for the FY2016-2017 their remuneration and adoption.
5) Address by President Prof. K. J. Nath.
6) Miscellaneous.

Working lunch at 1 P.M.

Notice (26 September 2017)

Proposed Revised Structural Relationship of the Centres / Regional Centres with the Institution of Public Health Engineers, India duly cleared by the Council of IPHE, India in its 9th meeting (2016-2018) held on 9th September, 2017 at IPHE Building, CK-58, Salt Lake City, Kolkata-700091 is attached seeking refinements, if any, from the Corporate Members of this Institution.

Members are requested to please go through the contents and suggest modification (s), if any, to enable this Institution to undertake administrative reforms for its smooth functioning.

Suggestion, if any, should reach us latest by 17th October, 2017.

(S K Neogi)
Secretary General
IPHE, India


Proposal for Modified Inter-se Relation bet. HQ. and RC PDF File

Role of Engineers in Infrastructure, Energy & Irrigation

Respected Sir/Madam

Sub: National Seminar on Role of Engineers in Infrastructure, Energy & Irrigation to be held at DSCE on 27 Sept 2017 – Reg.

“Seasonal Greetings”

I am very happy to inform you that the Department of Civil Engineering is organizing National seminar on Role of Engineers in Infrastructure, Energy & Irrigation on the occasion of Engineers day to commemorate the 157th birthday of Sir.M.Visvesvaraya.

Herewith first information brochure is enclosed.


With Regards,

Dr.H.K.Ramaraju
Professor and Head
Department of Civil Engineering
Dayananda Sagar College of Engineering
Shavige Malleswara Hills, K S Layout, Bangalore-560078, Karnataka,INDIA
Mobile:09845625608, Fax +91 80 26660789, Office:08042161619
Ph. : +91 8026662226 / 26665926


>>Brochure 1
>>Brochure 2 (Registration Form)
>>Brochure 3

JOURNAL OF THE INSTITUTION OF PUBLIC HEALTH ENGINEERS, INDIA Guidelines For Authors

Authors are requested to go through the following requirements and ensure adherence to these before mailing the technical papers for publishing in JIPHE. Possibility of delayed publication or non-publication can thus be avoided to a great extent. It is to be noted that acceptance of a paper for publication in JIPHE depends finally on the decision of the advisory council.

(A) Contribution : Papers based on practical experience, case studies and popular issues related to Public Health Engineering/Environmental Engineering are particularly welcome. Research findings related to above may also be sent.

(B) Length : Not more than 3000 words all inclusive (i.e. space for tables, figures etc duly considered as included) - preferably within 2500 words.

(C) Manuscript :

(a) Mode of presentation: Third Person.

(b) Quality of presentation : Brief, to the point, lucid and without repetition.

(c) Error-Freeness : Free from errors and omissions - typographical, grammatical, syntactical, punctuationwise and in spelling. Spelling should be British English as per concise Oxford Dictionary.

(d) Page Number : All pages must be numbered indicating serial number of each page and total number of pages contained in the paper, e.g. 3 of 5 indicating third page of a five paged paper.

(e) Identification : Each page must bear an identification of Article and name(s) of Author(s) in short at the top of each page.

(f) Choice of Types : Must be neat and sharp and should be such that differentiation of similar characters (e.g. 1, I&l) is possible such as Times New Roman, for example.

(g) Order of contents :

(i) Brief Title.

(ii) Name(s) of Author(s) with designation

(IPHE Membership grade and number is to be mentioned for a member author for our record.)

(iii) Abstract.

(iv) List of Notation.

(v) Body of Paper - with preferably not more than two (2) grades of subheadings.

(vi) Acknowledgement.

(vii) References and/or Bibliography

(viii) Full contact address(es) with postal PIN Codes, e-mail, Fax and Telephone Nos. of the Author(s) – Corresponding Author being specially marked.

(h) References and/or Bibliography : References shall be sequentially numbered (denoted by bracketed superscript numeral) in order of citation in the text. A list provided at the end under the title References shall have the details in the same numerical order of citation in the text. Whichever has been listed in the Reference List must be cited in the text and whichever has been cited in the text must be listed in the Reference List.

Bibliography is the title under which publications generally used in preparing the paper as help or source — but without any specific citation in the text — shall be listed.

Bibliography shall come after References if both are provided in the paper.

(i) Photographs, Illustrations, Graphs, Bar charts, Pie charts etc.These we are not in a position to print in colour and hence: these, in Original Photographs & Tracings and/or in Soft Copy must be of such quality that clear, sharp and legible Black & White reproduction is ensured. Photocopies or clippings of printed matters shall not be accepted unless very essential.

(j) Tables : Each must be numbered and be cited in the text.

(k) Unit : Shall be SI Units along with other units in parenthesis if necessary.

(D) Special Information :

(a) Paper-sheets used in the manuscript shall be in A4 size. Typing shall be on one side in double space leaving ample margin at the left side.

(b) Hard copies of manuscripts, securedly stitched, must be sent in Duplicate along with a soft copy secured enough against damage or breakage during transit.

(c) A paper is to be sent under coverage of a forwarding letter signed by the author(s). The forwarding letter shall contain a declaration ensuring :

(i) that the paper submitted is original

(ii) that the article has not already been sent for publication/published in JIPHE or anywhere else.

(d) Papers shall be submitted to : Editor, JIPHE, Institution of Public Health Engineers, India, CK-58, Salt Lake City (Near Tank No. 9), Kolkata - 700 091.

List for Last Minute Checks before sending a paper

Clause B : Length /Word limit.

Clause C (c) : Error-freeness.

Clause C (d) : Page numbers.

Clause C (e) : Identification.

Clause C (f) : Choice of types.

Clause C (g-ii) : Name(s) of Author(s)/IPHE Membership

Clause C (g-viii) : Contact address(es)/corresponding author.

Clause C (h) : References and/or Bibliography.

Clause C (i) : Photographs Illustrations, Graphs, Bar Charts, Pie Charts etc.

Clause D(b) : No. of hard copies/soft copy/securedness.

Clause D(c) : Forwarding Letter/Declaration.

Clause D(d) : Correctness of postal address/addresses.

EDITORIAL

One of the flagship projects recently launched by Govt. of India for improving quality of life in cities is Swachh Bharat Abhijan (Urban) Indian's urban population, as per Census 2011, is 377 million i.e. 31% of total population and this figure is likely to increase to 600 million by 2031. In 4041 statutory towns, close to eight million household do not have access to toilets and residents in these households defecate in the open. Untreated waste thus generated is the single biggest source of pollution of water resources.

"Swachh Bharat Mission" was therefore launched on 2nd October, 2014 for ensuring hygiene, waste management and sanitation across the nation. Two main objectives of Swachh Bharat Mission (Urban) are elimination of open defecation by construction of individual toilets, public toilets and community toilets, and eradication of manual scavenging by and scientific solid waste management.

Two key strategies under SBM (Urban) are to generate awareness about sanitation and its likeage with public health, hygiene and environment and to effect behavioural change regarding healthy sanitation practices. Information, Education and Communication (IEC) campaign has to be carried out more extensively for the purpose, so that target set up by SBM for achievement by Oct. 2, 2019, which is the birthday of Mahatma Gandhi, is reached.

This issue of the journal contains eight assorted articles in addition to usual features like "Notes and News", "Our Members", etc.

While thanking our learned authors for their valuable contributions, we would request the authors of pending articles to bear with us for some more time.

May I request the learned reader to offer their valuable suggestion for improving various features of the journal.

Editor, JIPHE

EDITORIAL

The theme of this year's celebration of World Water Day is "Waste Water"and the Campaign is "Why Waste Water".

Target set in Sustainable Development Goal (SDC) requires that by 2030, the proportion of untreated waste water should be halved and there should be substantial increase in recycling and safe reuse of waste water globally. Global demand for water is expected to grow by 50% by 2030 and most this demand shall be in cities. Consequently, quantity of waste water generated and its overall pollution load shall be increasing globally. But waste water management is grossly undervalued as a potentially affordable and sustainable souce of water, energy, nutrients and other recoverable materials. In fact, reused waste water from cities could address challenges like food production and industrial development. Through industrial symbiosis waste water can be used within business itself or between several businesses, as on an average, industrial water consumption is responsible for 22% of global water use. Agriculture in many countries is a potential source of environmental pollution due to use of chemical, fertilizers and pesticides. Improved waste water management can improve the health of workers by reducing risk of pathogen exposure. It may also create direct and indirect jobs in water dependent sectors. As such waste water could be seen not as a burden to be disposal of, but as a potential resources as its reuse after suitable treatment can provide economic and financial benefit.

This issue of the journal contains 8 assorted articles. Other usual features like "IPHE News", "Our Members", "Notes and News" have also been incorporated in this issue.

We would once again request our learned readers to offer their valuable suggestions for improving various features of the journal.

Editor, JIPHE

3 Volume XXXXV ● Number 1 ● April 2017

Authors are requested to go through the following requirements and ensure adherence to these before mailing the technical papers for publishing in JIPHE. Possibility of delayed publication or non-publication can thus be avoided to a great extent. It is to be noted that acceptance of a paper for publication in JIPHE depends finally on the decision of the advisory council. (A) Contribution : Papers based on practical experience, case studies and popular issues related to Public Health Engineering/Environmental Engineering are particularly welcome. Research findings related to above may also be sent. (B) Length : Not more than 3000 words all inclusive (i.e. space for tables, figures etc duly considered as included) - preferably within 2500 words. (C) Manuscript :

(a) Mode of presentation: Third Person. (b) Quality of presentation : Brief, to the point, lucid

and without repetition. (c) Error-Freeness : Free from errors and omissions - typographical, grammatical, syntactical, punctuationwise and in spelling. Spelling should be British English as per concise Oxford Dictionary. (d) Page Number : All pages must be numbered indicating serial number of each page and total number of pages contained in the paper, e.g. 3 of 5 indicating third page of a five paged paper. (e) Identification : Each page must bear an identification of Article and name(s) of Author(s) in short at the top of each page. (f) Choice of Types : Must be neat and sharp and should be such that differentiation of similar characters (e.g. 1, I&l) is possible such as Times New Roman, for example. (g) Order of contents :

(i) Brief Title. (ii) Name(s) of Author(s) with designation

(IPHE Membership grade and number is to be mentioned for a member author for our record.) (iii) Abstract. (iv) List of Notation. (v) Body of Paper - with preferably not more than two (2) grades of subheadings. (vi) Acknowledgement. (vii) References and/or Bibliography (viii) Full contact address(es) with postal PIN Codes, e-mail, Fax and Telephone Nos. of the Author(s) – Corresponding Author being specially marked. (h) References and/or Bibliography : References shall be sequentially numbered (denoted by bracketed superscript numeral) in order of citation in the text. A list provided at the end under the title References shall have the details in the same numerical order of citation in the text. Whichever has been listed in the Reference List must be cited in the text and whichever has been cited in the text must be listed in the Reference List.

COMPREHENSIVE STUDY ON INTEGRATED SOLID WASTE MANAGEMENT

Lakshmi C. Associate Professor, Civil Engineering Department, SJBIT

ABSTRACT

Energy is one of the most important factors for human development and to global prosperity. Present study deals with recovery of energy from anaerobically digested biomass resources such as cattle dung and hostel kitchen organic waste. In this regard anaerobic digester at lab level is fabricated to utilize the institute canteen waste for producing the biogas. Biogas production is a Clean, low carbon technology, useful for the efficient management and conversion of organic waste into clean renewable biogas and organic manure/fertilizers. It will give extensive knowledge of Design aspects of Biogas reactor and maintenance of reactor during the process. It has the potential for leveraging sustain-able livelihood development as well as tackling local and global land, air and water pollution. Also decomposed slurry/waste used as manure for gardening purpose. The amount of methane present in biogas is found to be 65%.To segregate methane from other gases such as H2S and Co2 purification by lime treatment is adopted. Further from the experimental work it was observed that bio methane is best alternative compared to LPG in respect of calorific value biogas and emission study. The present work will be worthy for academicians and people dealing with bio-energy, environmental pollution.

Key words : Anaerobic digestion, biomass.

INTRODUCTION

Improper solid waste management leads to substantial negative environmental impacts for example, pollution of air, soil and water, and gene- ration of greenhouse gases from landfills, and health and safety problems due to diseases spread by insects and rodents attracted by garbage heaps, and diseases associated with different forms of pollution. Municipal authorities charged with responsibility of providing municipal solid waste management services have found it increasingly difficult to play this role. The difficulty has been aggravated by lack of effective legislation, inade- quate funds, and services, and inability of municipal authorities to provide the services cost-efficiently. The upshot is that an increasing proportion of

because organic carbon can serve both as a source of energy and cell carbon, more carbon is required than for Eg. Nitrogen.

Activity has essentially ceased as a humus material commonly known as compost.

This paper was presented in the National Seminar on "Swatchh Bharat Drive for Solid Waste Management" held at Bangalore on 23rd September 2016

urban dwellers in developing countries, particularly the urban poor, will lack access to municipal solid waste management services and, consequently, suffer from pollution-related environmental and health problems. Fortunately, there are ways of dealing with or, at least, minimizing this problem.

MATERIALS ANDMETHODOLOGY

Solid waste management is the discipline associated with the control of generation, storage, collection, transfer and transport, processing and disposal of solid waste in a manner in accordance with best principles of public health, economics, engineering, conservation, aesthetics and other environmental considerations that is also responsive to public attitudes. This study also includes administrative, financial, legal, planning, and engineering functions involved in solution to all problems of solid waste. All the waste from human and animal activity that are normally solids and that are discarded as useless or unwanted. It refers to heterogeneous mass throw away from the urban community as well as the more homogeneous accumulation of agriculture, industrial and mineral waste. Some other common terms applied to solid waste are refuges, garbage and rubbish. The term refuse and solid waste are used more or less unanimously although the later term is preferred.

Aerobic Composting Microbiology

Fusing the aerobic composting process a succession of facultative and obligate aerobic micro organisms is active. In the beginning shares of composting rite, thermophilic bacteria predominate leading to thermophilic fungi, which appear after 5-10 days. In the final stages or caring period as it is sometimes known actinomycetes and molds appear because significant concentration of their micro-organisms may not be present. Critical parameters in the control of aerobic composting process include moisture content, C/N ratio, and temperature for most biodegradable organic waste once the moisture content is brought to a suitable level (50 to 60%) and the mass aerated microbial metabolism speeds up. The aerobic micro organic matter develop bell tissue from nitrogen, phos- phorus, some of the carbon and the other required nutrients. Much of carbon serves as a source of energy for the organisms and is burnt up and respired as CO

2

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Lakshmi C.

Aerobic Deposition Technology

Anaerobic composition is the putrefactive breakdown of the organic matter by reduction the absence of oxygen, leading to the production of methane (CH4) and carbon dioxide (CO2).In recent years there has been a great interest in applying the anaerobic digestion process for the processing of the organic fraction of MSW because of opportunity to recover the methane and the fact that digested material is similar to compost produce aerobically.

PROCESS DESCRIPTION

There are 3 basic steps involved in the process of producing the methane from organic fraction of MSW. The first step involves the preparation of organic fraction of the MSW. It also receives sorting and preparation and size reduction at the source level. The second step involves the addition of moisture and nutrients blending pH adjustment to about 6.8 and maintain a temperature of 550C. The anaerobic digestion is carried out in continuous flow reactor so that the contents are mixed completely. In the third step the mixed content after digestion as it out flow from the reactor it as to be reintroduce so that the microbial activity is kept continuously in progress.

PROCESS MICROBIOLOGY:

In the anaerobic composting of wastes, a number of anaerobic organisms work together to bring about the conversion of organic portion of the wastes to a stable end product. In anaerobic fermentation, the formation of methane takes place by. 1. The conversion of methane and water.

The picture below shows different types of food waste introduced into the pilot

CO

2

and hydrogen to

2. The conversion of formate and acetate to

6 Volume XXXXV ● Number 1 ● April 2017

Proteins Amino acids Lipids + O2+ Carbohydrates Nutrients Cellulose + Microorganisms ⎯→

Compost + New cells (Facultative and obligate aerobic thermophilic

⏐ ↓ Lignin Dead cells+

Ash CO2+

methane, carbon dioxide and water The methanogens and acidogens form a syntrophic (mutually beneficial) relationship in which the methanogens convert fermentation end products such as hydrogen, formate and acetate to methane and carbon dioxide and water.The methanogens are able to utilize the hydrogen produced by acidogens. The utilisation of hydrogen, produced by the acidogens and other anaerobes by the methanogens is termed as interspecies hydrogen transfer. In effect the methanogenic bacteria remove compounds that would inhibit the growth of acidogens.

Anaerobic transformation of solid waste can be described Organic matter New cell + + resistant by H

2

O + following Nutrients equation.

→ + Organic Matter + CO

2

+ CH

4

+ NH

3

+ H

2

S + Heat

METHODOLOGY; Aerobic Decomposition

For the purpose of aerobic composting a tank of dimension 3x.75x.5 m was constructed. The volume of the tank is 1.125m3. The materials used for constructing the tank were solid blocks, rapid hardening cement, fine aggregates and weather proof course. The tank was provided with the required slope in order to collect the leachate from one end of the tank. The pilot model built was cured for the required period and then the waste was introduced. For the purpose of composting a part of the total waste was chosen amounting to 280kgs. This was segregated from the starchy foods like roties, chapaties as also, oils, fats, meat, and bones. The food waste included for composting were only vegetable peals fruits green vegetables and also cooked food like rice grams and cereals.

Since the model was built next to sewage treatment plant, there was a constant production of slurry from the plant. The slurry obtained was collected and dried. The food waste of 50 kgs was introduced into the tank uniformly spread across the length and breadth of the tank every day. The dried slurry of 10 Kgs was laid over the food waste and 2 such layers were prepared every day. The moisture content of the food waste was determined before introducing into the tank. Test on moisture content were conducted and the moisture content was found to be 61 percent when the food was introduced into the tank. After introducing food waste temperature was recorded. The temperature varied between 35 degrees to 40 degrees. This was created by the windrows. Turning used to be done once in a week. The process was carried for 3 weeks with food waste introducing 50 Kgs each day 4 times.

There was a rapid rise in the temperature in the initial stages due to the biological activity. The temperature variation due to aeration system was recorded upto 5 degrees in two weeks .Temperature started falling as the biodegradable organic carbon is decreased. The lechate collected during the process was as little as one litre .This was reintroduced into waste water treatment plant.

Parameters Values (mg/L)

This study

1st 2nd 3rd 4th Sample Sample Sample Sample

Average pH 4.42 4.24 4.66 4.68

Volume reduction with time Time (weeks) Volume reduced (Litres approx)

1 500

2 380

3 295

4 180

5 110

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1st Test Sample

PROCESS OF DECOMPOSITION

It was noticed that several microorganisms had developed in the tank for bringing out the decomposition of food waste into organic matter.

Screening

In the process of screening 350 micron sieve was used to carry out screening. By screening the large lumps of organic matter could be broken into a fine medium. The product resulted out of the process is in the form of coarse grain powder having large surface area with different particle sizes. Decrease in size of the particle indicates the size reduction.

Compost

The compost obtained is of total quantity of 110 kgs. This serves as a fertilizer and also as manure for the greeneries distributed across the campus. The compost obtained out of the food waste when tested for its nutrient values was found to include carbon, nitrogen, phosphorous,potassium and results are tabulated.

Parametres Values

pH (1:5) 6.43

EC (1:100) 0.86

N (%) 0.77

P (%) 0.45

K (%) 0.41

ANAEROBIC DECOMPOSITION

Anaerobic decomposition of organic matter is brought about by putrefactive bacteria. These organisms will make use of nitrogen, phosphorous and other nutrients to live and to develop cell protoplasm, and they reduce the organic nitrogen to organic acids and ammonia. The carbon from the organic compounds which is not utilized in the cell protein is liberated mainly in the reduced form of

Lakshmi C.

The Picture below shows the final product as fertilizer or manure produced out of the food waste generated from the college canteens

methane. A small portion of carbon maybe respired as carbon di-oxide.

For anaerobic decomposition a pilot digester was fabricated out of mild steel. The digester is of floating type which does not allow the atmospheric air to interact within the food particles introduced to the outer cylinder.

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Anaerobic Digester.

Compressor

Lakshmi C.

ANAEROBIC DIGESTION IN DIGESTER

The material chosen for fabricating the equipment was mild steel. This model includes several parts to be welded and screwed.(Such as introducing inlets and outlets separately into the system). The model was painted with primer coating of 1mm in order to avoid rusting. In order to make sure that the model was leak proof, it was completely filled with water and let for 48 hours noting the initial height of the inner cylinder on the central pipe. After 48 hours it was noted that there was no drop in the rise of the inner cylinder. This ensured us that the tank was leak proof for water or air. Introduction of Food Waste and Slurry: In order to initiate the microbial activity in the food waste, cow dung was introduced in to the outer cylinder by mixing it with water on a proportion of 1:2. All the food waste which was collected from all the canteens of the campus was found to be of larger amount for which the pilot model was not sufficient to accommodate. Hence only 4 kg of food waste was introduced initially.since the inlet of the model was restricted by size. Either food particles below 30 mm sizes or by reducing the size to 30mm were introduced. The food waste mainly consisted of vegetable and fruit peel and cooked food excluding other hard food. The food waste was added for 5 days continuously. During each days process the introduced food consisting of carbohydrates, fats and proteins was getting converted into sugars, fatty acids, amino acids in the process of hydrolysis. In converting these acids into carbonic acids, alcohols, hydrogen, carbon dioxide and ammonia, acedogens or acid formers play a vital role. A third group of microorganisms known as methane formers convert the hydrogen, acetic acid and the carbon dioxide into methane gas and co2. These bacteria are strictly anaerobic and are responsible for conversion. The food waste was slowly increased by quantity up to 8 kgs in due course of 15 days. With the rise in the inner cylinder over the central pipe it

was noticed that the biogas was collected within the inner cylinder. Since the decomposed food waste rises to the top it covers the daily introduced food at the bottom of the tank.

The biogas consisted of methane, carbon dioxide and other gases quantity of gas obtained, mainly it was when H

2

S. tested In the total found to be consisting of 65 – 70 percent methane. The volume of gas produced was found to be 0.5 to 0.75m3 per kg of volatile solids destroyed. The pressure of this gas produced within the inner cylinder when measured was determined to be about 5- 7 kg per cm2.

As the pressure which was delivered by the pilot model was not sufficient enough for the gas to be utilized in various applications, the gas needed to be compressed in order to develop a better pressure. A manually operated pressure pump was designed and fabricated in order to compress the gas. The pump so designed has an inlet,an outlet& a well fabricated enclosed cylinder with a piston. A lever had to be used for pumping the gas. The compressor had a capacity of 0.150ft3 for every cycle (to and fro movement of lever). The pilot model delivered a pressure of 5-7kg/cm2 where as when the gas had been compressed into a gas cylinder a pressure of about 15 kg/cm2 was obtained.

RESULTS

The compost and the biogas produced out of the food waste generated from the college messes and the canteens have various applications. The compost produced out of the waste will be used as manure for the greeneries in and around the campus. As the compost consists of good nutrients it finds the use as fertilizer for plants. This reduces the cost of chemical fertilizer used to maintain the flora around the college campus. The process is environmental friendly by reducing the cost on transport, labor and saves the land nutrition.

Biogasification

The biogas was utilized in uncompressed and compressed form and found to have many applica- tions which could be used for different applications in the campus.

Uncompressed Gas

This gas can be used to burn mantel lamp. An attempt was made to burn a lamp over 2 hours spending 10 cubic ft.

The same uncompressed gas was tested for flame by burning the Bunsen burner. The blue flame indicated the presence of methane.

Compressed Gas

The gas was compressed mechanically using a

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Lakshmi C.

crude compressor designed for this project. The compressed gas when filled into the commercial cylinder finds its applications in cooking. The biogas was compressed to a pressure of 15 kg per cm2 into a commercial cylinder and was connected to the canteen gas pipeline for cooking food.

The gas was compressed mechanically using a crude compressor designed for this project. The compressed gas when filled into the commercial cylinder finds its applications in cooking. The biogas was compressed to a pressure of 15 kg per cm2 into a commercial cylinder and was connected to the canteen gas pipeline for cooking food.

The gas demand can also be defined using the daily cooking times. The gas consumption per person and meal lies between 150 and 300 litres biogas. For 1 litre of water to be cooked 30-40 litres of biogas, for half kg rice 120 – 140 litres of gas are required.

Biogas Lamps

The compressed gas has an application in illuminating mantle lamps. The bright light of a mantel lamp is the result of incandescence. The intense heat induced luminosity of special metals, so called rare earth like thorium, cerium are 1000 – 2000 centigrade. The light output is comparable with normal 40 watt bulb. One lamp consumes 120 – 150 litres biogas per day.

Automobiles

The compressed gas can be used for running automobiles for commuting within the campus. To demonstrate this, the gas was compressed into a commercial cylinder and when connected to automobile like the auto rickshaw with slight changes in the combustion engine was found to be useful in commuting short distances within the campus.

Biogas-fueled Gen Set

If the output of a biogas system is to be used for fueling engines, the plant must produce at least 10 m3 biogas per day. For example, to generate 1 KWH electricity with a generator, about 1m3 biogas is required. Small-scale systems are therefore unsuitable as energy suppliers for engines.

CONCLUSIONS

The institution is spread over an area of 29 acres and houses about 4 canteens including a student's mess. The college produces on an average 550Kgs of food waste every day. This waste can be used as the input to the system. The system generates bio-gas using anaerobic decomposition

and organic compost using aerobic decomposition. A separate compression unit also has been developed for compressing the bio-gas generated. The system is one of the very few attempts to use food waste as input. The pilot bio-gas plant can take an input of about 500 liters of food waste while the composting plant can take an input of about 1000 liters of food waste. The results obtained included: ➢ Production of 110 kilos of compost using food

waste of about 270 kilos ➢ Generation of about 3 cubic meters of gas for

an input of 200 kilos of food waste The applications demonstrated by the pilot are: ➢ Use of the bio-gas generated for cooking food

in the canteen ➢ Illumination of mantel lamps ➢ Running of an automobile using compressed

gas The canteen produces about 500 kilos of food waste every day comprising vegetable peels and cooked food. The system when implemented in a larger scale would provide the following benefits:

Generation of Compost ➢ Meet the gardening requirements in the

campus ➢ Saving of money on transport, labour, ➢ Stop ill-effects of disposing unprocessed food

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Lakshmi C.

waste directly to the environment. Ill-effects include health hazards, foul smell, generation of leachate gases, etc.

REFERENCES 1. J. Walter Fitts& Jerry B. Fitts, "Under- standing Composting", ISBN: 0-86619-207- 7[C] 1984. 2. Experimental Studies of Anaerobic Digestion of Organic Fraction of Municipal Solid Waste Using a Bioreactor with Integral Flow Features1Charles N. Agulanna, 1Goddy N. Onuoha, 2Emmanuel E. Anyanwu,1Projects Development Institute (PRODA) Enugu,PMB 01609, Enugu State, Nigeria2Federal University of Technology 3. Characteristics of municipal solid waste and a proposed management plan for Kharagpur, West Bengal, India. Resource conservation and Recycling 5, pp 166-174, 2009. 4. R.M.Espinosaet. al., Integrated urban solid waste management programme in Mexican University. Waste Management, 28, pp 527- 532, 2008. 5. Veronica Ebot Manga et. al., Waste management in Cameroon – A new policy perspective. Resource conservation and Recycling. 52, pp 592-600, 2008

11 Volume XXXXV ● Number 1 ● April 2017

Application of Rotating Biological Contactors (RBCs) in the Treatment of Industrial Waste – A Review

K. Stalin* Assistant Professor Dr. Pauls Engineering College, NH-66, Pulichpallam, Vanur Tk., Villupuram Dist. Tamilnadu Pin: 605 109 E-mail: nilats_mtech@yahoo.com

Dr. Y. R. M. Rao Principal, Dr. Pauls Engineering College, NH-66, Pulichpallam, Vanur Tk.,Villupuram Dist. Tamilnadu Pin: 605 109 E-mail: dryrmrao@rediffmail.com

Abstract

Rotating biological contactors (RBCs) constitute a very sole and superior alternative for biodegradable organic matter and nitrogen removal due to the reasons of their feasibility, simplicity of design and operation, short start-up, low land area requirement, low energy requirement, low operating and maintenance cost and treatment efficiency. The paper is mainly focused on the performance of RBCs like rotational speed, organic and hydraulic loading rates, retention time, bio film support media, staging, temperature, influent wastewater characteristics, bio film characteristics, dissolved oxygen levels, effluent and solids recirculation, step feeding and medium submergence. RBCs design considerations; operational problems and assessment with other wastewater treatment systems are also reported.

Key words: Biofilm, Grey water, Influent, Rotating Biological Contactor, Hydraulic Retention Time, organic loading, wastewater

1.0 Introduction

The upper crust of the earth surface is covered with water by 70% and land by 30 %. Almost 97 % volume of the total water is present in the sea, which is unusable due its high salt (mostly Nacl) concentration. Only 0.3 % of the total water available is usable for living organisms. With limited natural resources, demand for usable water is increasing day by day due to population explosion and industrial growth. As a result, India and other countries are going to meet water scarcity by 2030. Since the natural resources are limited, hence sustainable activities should be planned for future generation. Industrialists are generally of the opinion “spending money on waste treatment is waste” and hence treatment part is neglected. Hence, there is a need to treat the wastewater for recycling by recovering the useful ingredients. This will help in preserving the natural resources. (International water Management Company, May 2, 2011).

Earlier, the objectives of wastewater treatment were removal of suspended and floatable material, biodegradable organics and elimination of pathogens. The wastewater was normally treated with primary, secondary and advanced treatment methods. The primary treatment includes equalization, neutralization, screening, grit removal, primary sedimentation, etc and the secondary treatment processes include the biological and/or chemical treatment processes. The advanced treatment methods are namely denitrification, phosphorous removal, carbon adsorption, ion exchange, electrodialysis, reverse osmosis, polishing pond, etc. Activated sludge process, trickling filter, oxidation ditches, aerated lagoon, stabilization pond, rotating biological contactor, etc. are some of the biological treatment processes. (Metcalf and Eddy 2004).

The objective of secondary treatment is to remove the residual organics and suspended solids from the effluent of primary treatment. In the most cases, secondary treatment follows primary treatment and involves the removal of dissolved biodegradable and colloidal organic matter using aerobic biological treatment processes. Aerobic biological treatment is performed in the presence of oxygen by aerobic microorganisms (principally bacteria) that metabolize the organic matter present in the wastewater, thereby producing more microorganisms and inorganic end-products like CO2, NH3, and H2O (Metcalf and Eddy, 2004).

2.0 ROTATING BIOLOGICAL CONTACTOR

A rotating biological contactor (RBC) is a type of an attached growth bioreactor that offers an alternative technology to the conventional activated sludge process. The first RBC was installed in West Germany in 1960, later it was introduced in the United States and Canada. In United States, rotating biological contactors are being used for industries which are producing wastewater with high BOD. The rotating packs of discs (known as the media) are installed in a tank or trough and rotate between 2-5 revolutions per minute. Polythene, PVC and expanded polystyrene are commonly used plastics for the media of the rotating discs. The shaft of the rotating disc is aligned with the flow of wastewater, so that discs rotate at the right angle to the flow with several packs. About 40% of the disc area is immersed in the wastewater. Biological growth is attached to the surface of the discs and forms a slime layer.

When the disc rotates, the wastewater comes in contact with the atmospheric air for oxidation. The rotation helps to slough off excess solids. The discs can be staged in series to obtain more detention time or degree of removal.

The discs consist of plastic sheets, ranging from 2 - 4 m in diameter and upto 10 mm in thickness. Several modules may be arranged in parallel and/or in series to increase the length of flow and to meet the treatment requirements. Most RBC systems design will include minimum 4 or 5 modules in series to obtain nitrification of wastewater (Rotating Biological contactor – Wikipedia).

Biofilms (the biological growth) attached to the discs, assimilate the organic materials of the wastewater. Aeration is provided by the rotating action, which helps to expose the media to the air after contacting with the wastewater, facilitating the degradation of the pollutants. The degree of wastewater treatment depends upon the surface area of the media, quality and volume of the inflow wastewater (A. P. Pajak and R. C. Loehr, 1976).
The inherent limitations of RBC, is the lack of operational flexibility. Once the plant is designed and installed, little can be done to alter the operation. On the other hand, the RBC’s lack of flexibility gives the process simplicity and stability. As long as the discs and media keep rotating and the hydraulic loading remains within the design capacity, the RBC normally will function properly. This process, like all other biological treatment processes, does have its limitations. Organic and hydraulic shock loading as well as toxic discharge will tend to decrease the process efficiency.

Excess slime, which has built up on the RBC has been sloughed off into the wastewater. Hence, after being treated in RBC, the wastewater is sent to the secondary settling tank (SST). This sloughed off slime and other sludge settle to the bottom of the SST and the effluent is disposed off. Sludge from the SST is pumped to the sludge digester for further treatment (A. P. Pajak and R. C. Loehr, 1976).

The use of simple mechanical components for the process, results in very low maintenance cost. Mainte-nance is only limited to greasing of bearings and inspecting the chains and sprockets. The low speed of disc is used in this process to achieve sufficient mixing and aeration with relatively low power consumption (Nahid P. et al 2001).

Since the metabolic rate of the bio-mass would be decreased with low temperature. RBCs are usually covered or enclosed. The rotating disc process is normally designed on the basis of hydraulic loading. At a specific hydraulic loading rate, specific percentage of BOD reduction is obtained. Thus, the percentage of BOD reduction is mainly a function of the hydraulic loading rate and hydraulic detention time (B. Guimaraesa et. al, 2005).

2.1 Advantages of RBC

● Consistent process results
● Stable operation without frequent supervision
● Lower expansion and retrofit costs due to modular construction and reduced excavation
● Short wastewater hydraulic retention time
● Minimal head loss through system
● Low energy consumption
● The only maintenance required is simple drive and bearing lubrication
● Reduced life cycle costs as compared to suspended growth systems
● Simple in operation since no sludge recycle
● Operator friendly
● Easy for up gradation and multiple application.

2.2 Factors Affecting the Performance

The performance of RBC depends upon several design parameters which include (i) rotational speed (ii) organic loading (iii) hydraulic loading rate (iv) hydraulic retention time (HRT) (v) RBC media (vi) temperature (vii) staging (viii) influent wastewater characteristics (ix) biofilm characteristics (x) step feeding (xi) disc submergence

2.2.1 Rotational speed

The rotational speed of the RBC discs is a very important parameter that affects nutrient and the oxygen mass transfer in the biofilm and consequently substrate removal. Usually, an increase on the speed of rotation increases the dissolved oxygen concen- tration available to the microorganism and as a result they are able to degrade the substrate at a higher rate (K.H Radwan and T.K.Ramanujam, 1995). However, increasing the rotational speed leads to higher power consumption, which may not be econo- mical for wastewater treatment applications. Besides, if the rotational speed is too high the microorganisms (bioflim) will be stripped off the media, deteriorating the effluent quality and lowering the biodegradation rate in the reactor. Packed supports will provide consi- derably more oxygenation than disc RBCs at the same rotational speed, but they require greater power consumption.

2.2.2 Organic loading

The variation of the organic loading rate is generally accomplished by changing the influent flow rate or the HRT, which also results in a change in the hydraulic loading (G. D. Najafpour and A. A. Zinatizadeh, 2005). As the applied organic loading rate increases the removal efficiency of RBC decreases. Reduction in efficiency may be an indica- tion of limitation in dissolved oxygen. Overloading problems can be avoided by removing baffles between the stages to reduce surface loading and increased oxygen transfer level. Oxygen transfer methods include (i) supplemental aeration (ii) step feeding (iii) recycling and (iv) introduction of an anaerobic system such as up flow anaerobic sludge blanket (UASB) reactor prior to the aerobic RBC systems.

2.2.3 Hydraulic loading

Increasing the flow rate through the bioreactor reduces the liquid retention time in the system and results in a reduction in removal efficiency. In defined conditions, increasing hydraulic loading also leads to an increase of attached biomass on RBC media surface (L. Alemzadeh and M. Vossoughi, 2001). Hydraulic loading rates vary widely depending on the design the substrate being removed and the effluent concentration desired (John N. Hochheimer and fred Wheaton, 1998). Typical hydraulic loading rate range recommended by RBC manufacturers (full-scale) is 1.292-6.833 dm3/h (G.Tchobanoglous and FL Burton, 1995). Due to the large amount of biological mass present (low operating feed / microorganisms), RBCs offer good stability under high or toxic hydraulic and organic loadings (S. Sirianutapiboon 2006).

2.2.4 Hydraulic retention time (HRT)

Longer contact times improve the diffusion of the substrate into the biofilm and its consequent removal of the influent (G.D Najafpour and A. A. Zinatizadeh, 2005). This trend is also verified with toxic and heavy metals substrates (S. C. Costley and F. M. Wallis, 2001). Too short HRT will result in low removal rates, whereas too long HRT will not be economically feasible. In order for a biological system to compete successfully with conventional physicochemical treatment methods, the shortest possible HRT associated with the most efficient removal rates is required (S. C. Costley and F. M. Wallis, 2001). Significant advantage offered by full scale RBCs is to require short hydraulic retention periods (generally less than 1h) (Zhongming zheng and Jeffrey Philip Obbard, (2002).

2.2.5 RBC Media

The media used for RBCs are actually produced from Styrofoam, Polycarbonate sheets or high density polyethylene (HDPE) and others. HDPE containing UV inhibitors such as carbon black is the material most commonly used and is provided in different configurations or corrugation patterns (G. Tchobano- glous and F. L. Burton, 1995). Corrugations enhance structural stability, improve mass transfer and increase the available surface area (Grady et. al, 1999). The type of biofilm supporting media are classified on the basis of surface area provided and are commonly termed as low or standard density, medium density and high density. Standard-density media are defined as having a surface area of about 115m2/m3 of reactor with larger spaces between media layers and are normally used in the lead stags of a RBC process. Medium and high density media have surface areas of about 135-200 m2/m3 of reactor and are used typically in the middle and final stages of a RBC system where thinner biological growth occurs (G. Tchobanoglous and F. L. Burton, 1995). Standard density media must be used in the first two stages that are highly loaded or where microbial growth possible.

Random packed media have been providing more surface area for attachment of the biofilm within the RBC reactor, contributing to higher mass transfer efficiency due to increased turbulence. Besides they have low energy consumption and the fabrication cost is nearly one third that of discs (A. J. Ware et al, 1990). Different types of packing such as pall rings, saddles and cylindrical plastic elements with distinctive sizes can be used in random packed RBC systems (P. Mathure and A. W. Patwardhan, 2005).

2.2.6 Temperature

Temperature is one of the most important factors that affect the rate of biological processes and consequently influences RBCs performance. At limited conditions, an increase in the influent temperature leads to an increase in the microbial activity and a higher substrate removal can be observed in all RBC stages (Banerjee, G. 1997b). Low influent temperatures can adversely affect biofilm establishment, particularly in its early stages. When waste water temperature is less than 13 °C organic and nitrogen removal rates may decrease. Generally, when the temperature drops from 13°C to 5oC nearly 2.5 times more media surface area is required for achieving the same performance (Rodgers M. and Zhan X-M (2003). In biofilms the nitrification process is less temperature – dependent than in activated sludge. The nitrification rate increases by about 4.5% per oC. Year round operation requires that rotating contactors be covered to protect the biological growth from freezing temperatures or excessive heat gain, which accelerates media deterioration. Covers also helpful to reduce heat are loss and minimize algae growth. Individual covers are preferable than entire installations being placed in buildings (G. Tchobanoglous and FL Burton, 1995).

2.2.7 Staging

Staging of RBC media is recommended to maximize removal of (NH in a 4 tank +-N). or Stages using are a BOD 5 and ammonia nitrogen accomplished by using baffles series of tanks. Typical RBC staging arrangements are illustrated in Fig.1 As the wastewater flows through the system; each subsequent stage receives an influent with an organic concentration lower than the previous stage. As the wastewater moves to the second and subsequent stages the RBC tends to first remove ammonia and then nitrite with the final product being nitrate, assuming that the RBC is sized and operated correctly (John.N.Hochheimer and fred Wheaton, 1998). When there is recycling of wastewater from the last stage to the first one, denitrification may be achieved in the first stage, where there is high organic loading and low dissolved oxygen content. Staging in the design of RBC systems is especially important at higher organic loadings and also if high effluent treatment quality is required. Moreover, staging of RBC decreases the detrimental effect of shock load on the performance of the system. The number of stages to be used depends on the organic content of the influent, flow rate and several other variables.

2.2.8 Influent wastewater characteristics

The substances in influent and their concentration levels may play a significant role in the operation of RBCs for example; the flux into the biofilm may be smaller for large and slowly biodegradable compounds. The presence of particulate organic matter can reduce the flux of soluble substrate since the particulate matter occupies space within the biofilm, which decrease the rate of biodegradation (Grady et. al, 1999). When sulphide is present, either in the influent wastewater or by its production deep within the biofilm, sulphide oxidizing bacteria such as beggiatoa will grow on the biofilm surface. The production of sulphide within the biofilm is due to oxygen depletion. Beggiatoa will compete with heterotrophic organisms for oxygen and in extreme cases will take over the first-stage of overloaded RBCs, shifting the load to the next stage and progressively taking over the system. RBC units properly designed and supplemented with essential nutrients consistently produce the best effluents and maintain biofilm on the media with better adhesion characteristics.

2.2.9 Biofilm characteristics

Biofilm present on disc media plays important role in moving the organic and inorganic substrate present in wastewater, which they used it for their metabolism and treating wastewater. Micro-organisms present in the wastewater adhere to the disc surfaces within 1 to 4 weeks and form a slime layer biofilm ranging from 1 to 4 mm in thickness. The biofilm after reaching a critical thickness, microorganism in deep are unable to receive nutrients and oxygen, they are no longer able to stick to disc and slough off. Large surface area allows a large, continuous and stable biomass population to develop on disc. The thickness of biofilm is not uniform since sloughing process occurs randomly. Sloughed biofilm and suspended solids are washed out of the contactor as the wastewater which is later removed in settling tank or at secondary clarification. The biomass contains different types of microorganisms. Initially brown color organisms is considered as healthy biomass where as white and grey biofilm are regarded as unhealthy ones. (N. E. Kinner and C. R. Curds, 1987).

2.2.10 Step-feeding

To increase the process capacity, to have a more robust performance and to reduce or prevent overloads, the capability to step-feed RBC stage(s) should provide. Working in step-feed mode will improve the removal rates and found higher dissolved oxygen values. The combined effect of step-feed and effluent recirculation has increased RBC performance, but for a simple soluble substrate. (Pradeep et. al, 2011).

2.2.11 Disc submergence

Disc submergence along with other factors affects the biological process. Generally, partially submerged RBCs are used for nitrification and fully submerged for denitrification. The experiment was carried out with three submergence levels from 23.7, 31.4 and 36%. As disc submergence was increased from 31.4 to 36% the removal efficiency of Total Chemical Oxygen Demand (TCOD) and Soluble Chemical Oxygen Demand (SCOD) improved and result obtained were 74.9 to 87.5% and 89.5% and 93.75% respectively (G.D Najafpour and A. A. L. Zinatizadeh, 2005). For aerobic RBC submergence more than 50% is not practically possible as the bearing holding the shaft will be immersed in wastewater and can get deteriorated affecting the working of shaft (Pradeep et. al, 2011).

3.0 PERFORMANCE EFFICIENCY OF RBC:

The performance of RBC is verified by various investigators under different operating conditions using various kinds of wastewater. The results obtained by them are consolidated and presented in Table1.

4.0 CONCLUSION

The management of the medium and small scale industries feel burden to treat wastewater if the cost involvement is high. Hence there is a broad scope for cheaper and compact unit processes or ideal solutions for such issues. Rotating biological contactor is most popular due to its simplicity, low energy and less land requirement. The rotating biological contactors are fixed film moving bed aerobic treatment processes and able to sustain shock loadings. Unlike activated sludge processes (ASP), trickling filter etc. rotating biological contactor does not require recirculation of secondary sludge and hydraulic retention time is also low.

Rotating biological contactor is very effectively used for treatment of wastewater to remove the very high organic loading. And now a days, the RBC is used for aerobic treatment process for removal of organic concentration, also anaerobic RBC is used for de-nitrification process. Scope for several structural modifications is there, such as changing rotational speed to increase dissolve oxygen level, variation of organic loading, disc submergence and step feeding during multiple staging to improve RBC’s performance.

ACKNOWLEDGMENT

The authors are thankful to Mr. N K Mandal and Mr. Kaviyarasan, Dr.Paul’s Engineering College, Villupuram district for extending support in preparing this paper.

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