PROJECT REPORT - KSCST · 2016-08-25 · LITERATURE REVIEW 2.1 INTRODUCTION Water is vital to the existence of all living organisms, but this valued resource is increasingly being

“STUDIES ON NATURAL FIBROUS MATERIALS AS FIXED

AERATED BEDS FOR DOMESTIC WASTEWATER

TREATMENT”

PROJECT REPORT (Sponsored by KSCST)

In partial fulfillment of the requirements for the

award of the degree of

“BACHELOR OF ENGINEERING

IN

ENVIRONMENTAL ENGINEERING”

Submitted by

ADITYA RAM P.N ERISA SHILLA

(4AI12EV001) (4AI12EV005)

MONIKA. K SEEMA. M. DODDAMANI

(4AI12EV009) (4AI12EV015)

Under the guidance of

Mrs. SHRUTHI C.G , M.Tech(PhD).

Asst.Professor

Department of Env. Engg

AIT, Chikkamagaluru.

DEPARTMENT OF ENVIRONMENTAL ENGINEERING

Adichunchanagiri Institute of Technology (Affiliated to Visvesvaraya Technological University)

CHIKMAGALUR-577102

2015-2016

ADICHUNCHANAGIRI INSTITUTE OF TECHNOLOGY

CHIKMAGALUR-577102

CERTIFICATE

This is to certify ADITYA RAM P. N (4AI12EV001), ERISA SHILLA (4AI12EV005),

MONIKA K (4AI12EV009), SEEMA. M. DODDAMANI (4AI12EV015) have submitted

the project work and report entitled, “STUDIES ON NATURAL FIBROUS MATERIALS

AS FIXED AERATED BEDS FOR DOMESTIC WASTEWATER TREATMENT”. They

have satisfactorily completed the project work prescribed by VISVESVARAYA

TECHNOLOGICAL UNIVERSITY, BELGAUM for 8th

Semester B.E curriculum of

ENVIRONMENTAL ENGINEERING in this institute for the academic year 2015-2016.

Guide Mr.D.L Lakshmi Narasimha, M.Tech.

Mrs. Shruthi C.G, M.Tech(Ph.D) Prof. and H.O.D

Asst. Professor Department of Env. Engg

Department of Env. Engg.

Dr. C.K Subbaraya, M.Sc, Ph.D.

Principal

Name of Examiners: - Signature:-

1. ______________________ ______________________

2. ______________________ ______________________

DEPARTMENT OF

ENVIRONMENTAL ENGINEERING

ADICHUNCHANAGIRI INSTITUTE OF TECHNOLOGY,

CHIKMAGALUR-577102

APPROVAL

The project entitled, “STUDIES ON NATURAL FIBROUS MATERIALS AS FIXED

AERATED BEDS FOR DOMESTIC WASTEWATER TREATMENT” is hereby

approved as a credible study of an Engineering subject carried out & presented in a

satisfactory manner to warrant its acceptance as a pre-requisite to the degree of

“BACHELOR OF ENGINEERING IN ENVIRONMENTAL ENGINEERING” of

VISVESVARAYA TECHNOLOGICAL UNIVERSITY, BELGAUM during the

academic year 2015-2016.

Guide Mr. D.L Lakshmi Narasimha, M.Tech.

Mrs. Shruthi C.G, M.Tech(Ph.D). Prof. and H.O.D

Asst. Professor Dept. of Env.Engg

Dept. of Env. Engg

—————————————

Dr. C.K Subbaraya, Ph.D.

Principal

DEPARTMENT OF

ENVIRONMENTAL ENGINEERING

ACKNOWLEDGEMENT

Bowing our head before The almighty God; Cherisher and Sustainer of the worlds, we seek

his blessings.

We express our sincere and humble pranamas to his holiness SRI SRI SRI

PADMABUSHANA BHAIRAVAIKYA Dr. BALAGANGADHARANATHA MAHA

SWAMIJI and SRI SRI SRI Dr.NIRMALANANDANATHA MAHA SWAMIJI and

seeking their blessings.

The satisfaction that accompanies the completion of any task would be incomplete without

naming the people who made it possible and whose constant guidance and encouragement

made the work seek perfection.

We owe the success of the project to our respected principal Dr.C.K.SUBBARAYA without

whose constant encouragement, the completion of the project work would not have been

possible.

The co-operation of Mr. D.L LAKSHMINARASIMHA Associate Prof. and Head of the

Dept. of Environmental engineering are beyond comparisons and I am extremely obliged to

him.

Its our pleasure to express deep gratitude and sincere thanks to our project guide Mrs.

SHRUTHI C.G, Assistant professor, Dept. of Environmental Engineering.

We thank our project coordinator Dr. B. M Kiran, Associate Professor, Department of

Environmental Engineering for advice and co-operation during this project work.

We express our sincere gratitude to KSCST for approving our project.

We take this opportunity to thank and express our gratitude to our dear parents who have

given us the right education because of which we have been able to reach this stage and have

always been a source of inspiration.

We are also thankful to all the teaching and non-teaching staff of our department who has

made concrete contribution to successful completion of this project work by extending their

help in various capacities.

Sponsored

by

KSCST

Studies on natural fibrous materials as fixed aerated beds for domestic wastewater treatment

DEPT OF ENV ENGINEERING 1 AIT, CKM

CHAPTER 1

INTRODUCTION

1.1 GENERAL

Water is considered as the most important and priceless commodity on planet Earth. Water

on earth moves continually through the water cycle of evaporation and transpiration,

condensation, precipitation and runoff, usually reaching the sea. It is one of the most essential

thing that is required for every living being. In order to develop a healthy and hygienic

environment, water quality should be monitored such that it lies within the respective

standards.

Wastewater is liquid waste discharged by domestic residences, commercial properties,

industry, agriculture, which often contains some contaminants that result from the mixing of

wastewater from different sources. Wastewater obtained from various sources need to be

treated very effectively in order to create a hygienic environment. If proper arrangements for

collection, treatment and disposal of all the waste produce from city or town are not made,

they will go on accumulating and create a foul condition that the safety of the structures such

that building, roads will be damaged due to accumulation of wastewater in the foundations. In

addition to this, disease causing bacteria will breed up in the stagnant water and the health of

the public will be in danger.

The principal aim of wastewater treatment is generally to allow human and industrial

effluents to be disposed of without danger to human health or unacceptable damage to the

natural environment. Therefore in the interest of the community of the town or city it is most

essential to collect, treat and dispose of all the wastewater of the city in such a way that it

may not cause harm to the people residing in the town. The extent and the type of treatment

required, however depends on the character and quality of both sewage and sources of

disposal available.

The sewage after treatment may be disposed either into a water body such as lakes, streams,

river, estuary and ocean or into land. It may be used for several purposes such as

conservation, industrial use or reclaimed sewage effluent in cooling systems, boiler feed,

process water, reuse in agriculture, horticulture, sericulture, watering of lawns. Wastewater



reuse is becoming increasingly popular, especially in geographies where potable water is in

short supply.

Reduction of strength of domestic wastewater using two different bed materials Areca Husk

fibre and Agava sisalana fibre as a filter media is one such type of treatment method adopted.

The utilization of fixed films for wastewater treatment process has been increasingly

considered due to inherent advantages over suspended growth system. The present work is

intended to study the application of the comparative study between the fibres ie., Areca fibre

and Agava sisalana as a fixed bed for treating domestic wastewater and to know the

comparative removal efficiency of COD, BOD ,nitrate, sulphate, chloride with conventional

gravel bed in a small volume reactor.

Areca husk fibre is a versatile natural fibre extracted from mesocarp tissue, or husk of the

areca fruit. It belongs to the species areca catechu L., under the family palmacea and

originated in Malaya Peninsular, east India. Sisal fibre (Agave sisalana species) is obtained

from the leaves of this plant. The lustrous strands, usually creamy white, average from 80 to

120 cm in length and 0.2 to 0.4 mm in diameter. Sisal fibre is fairly coarse and inflexible. It is

valued for cordage use because of its strength, durability, ability to stretch, affinity for certain

dyestuffs, and resistance to deterioration in saltwater.

This method of treatment adopted using Areca husk and Agava sisalana fibres as a filter

media follows the principle of trickling filter in which wastewater is made to trickle over a

filter media containing seeding agent, due to biological action, the inorganic compounds

present in wastewater gets decomposed resulting in the reduction of strength of the

wastewater.

1.2 OBJECTIVES

The main objective of the study aims at treating the domestic wastewater in a fixed film

reactor filled with Agave sisalana fibres and Areca husk fibres.

The specific objectives are:

1. To study the performance of the Agave sisalana fibres and Areca husk fibres used as

filter media at different contact periods.

2. To study the comparative removal efficiency of COD, BOD, sulphate, nitrate using

Agave sisalana and Areca husk fibres.



CHAPTER 2

LITERATURE REVIEW

2.1 INTRODUCTION

Water is vital to the existence of all living organisms, but this valued resource is increasingly

being threatened as human populations grow and demand more water of high quality for

domestic purposes and economic activities. Among the various environmental challenges of

that India is facing this century, fresh water scarcity ranks very high. The key challenges to

better management of the water quality in India are temporal and spatial variation of rainfall,

improper management of surface runoff , uneven geographic distribution of surface water

resources, persistent droughts, overuse of groundwater, and contamination, drainage, and

salinization and water quality problems due to treated, partially treated, and untreated

wastewater from urban settlements, industrial establishments, and run-off from the irrigation

sector besides poor management of municipal solid waste and animal dung in rural areas.

Wastewater is any water that has been adversely affected in quality by anthropogenic

influence. It comprises liquid waste discharged by domestic residences, commercial

properties, industry, and/or agriculture and can encompass a wide range of potential

contaminants and concentrations. In the most common usage, it refers to the municipal

wastewater that contains a broad spectrum of contaminants resulting from the mixing of

wastewaters from different sources. Wastewater also known as sewage originates from

residential commercial and industrial area.

Wastewater engineering is that branch of environmental engineering in which the basic

principles of science and engineering are applied to solving the issues associated with the

treatment and reuse of wastewater. The ultimate goal of wastewater engineering is the

protection of public health in a manner commensurate with environmental, economic, social,

and political concerns. When untreated wastewater accumulates and is allowed to go septic,

the decomposition of the organic matter it contains will lead to nuisance conditions including

the production of malodorous gases. In addition, untreated wastewater contains numerous

pathogenic microorganisms that dwell in the human intestinal tract. Wastewater also contains

nutrients, which can stimulate the growth of aquatic plants, and may contain toxic

compounds or compounds that potentially may be mutagenic or carcinogenic. For these



reasons, the immediate and nuisance-free removal of wastewater from its sources of

generation, followed by treatment, reuse, or dispersal into the environment is necessary to

protect public health and the environment.

Besides that, the purpose of wastewater treatment is to remove pollutants that can harm the

aquatic environment if they are discharged into it. Because of the deleterious effects of low

dissolved oxygen concentrations on aquatics life, wastewater treatment engineers historically

focused on the removal of pollutant that would deplete the DO in receiving waters.

Biological treatment is an important and integral part of any wastewater treatment plant that

treats wastewater from either municipality or industry having soluble organic impurities or a

mix of the two types of wastewater sources. The obvious economic advantage, both in terms

of capital investment and operating costs, of biological treatment over other treatment

processes like chemical oxidation; thermal oxidation etc. has cemented its place in any

integrated wastewater treatment plant affected in quality by anthropogenic influence.

Itcomprises liquid waste discharged by domestic residences, commercial properties, industry,

and/or agriculture and can encompass a wide range of potential contaminants and

concentrations. In the most common usage, it refers to the municipal wastewater that

contains a broad spectrum of contaminants resulting from the mixing of wastewaters from

different sources. Wastewater also known as sewage originates from residential commercial

and industrial area.

There are several opportunities for improving wastewater irrigation practices via improved

policies, institutional dialogue, and financial mechanisms, which would reduce risks in

agriculture. Effluent standards combined with incentives or enforcement can motivate

improvements in water management by household and industrial sectors discharging

wastewater from point sources. Segregation of chemical pollutants from urban wastewater

facilitates treatment and reduces risk. Strengthening institutional capacity and establishing

links between water delivery and sanitation sectors through inter-institutional coordination

leads to more efficient management of wastewater and risk reduction.

Filtration is one of the oldest and simplest methods of removing those contaminants.

Generally, filtration methods include slow sand and rapid sand filtration. Reliable operation

for sand filtration is possible when the raw water has low turbidity and low suspended solids.

For this reason, when surface waters are highly turbid, ordinary sand filters could not be used

effectively.Therefore, the roughing filters are used as pretreatment systems prior to sand



filtration. Furthermore, roughing filters could reduce organic matters from wastewater.

Therefore, roughing filters can be used to polish wastewater before it is discharged to the

environment.

India, being an economy in transition from a developing to a developed nation, faces two

problems. On the one hand there is a lack of infrastructure and on the other, an ever-

increasing urban population. The urban population in India has jumped from 25.8 million in

1901 to about 387 million (estimated) in 2011. This has thrown up two self-perpetuating

problems, viz. Shortage of water and sewage overload. It is estimated that by 2050, more than

50 per cent of the country’s population will live in cities and towns and thus the demand for

infrastructure facilities is expected to rise sharply, posing a challenge to urban planners and

policymakers.

Public services have not been able to keep pace with rapid urbanization. Water supply,

sanitation measures, and management of sewage and solid wastes cover only a fraction of the

total urban population. There is clear inequity and disparity between the public services

received by the inhabitants, depending on their economic strata. Slum dwellers have always

received least attention from the civic authorities. The rapid growth of urban population has

taken place due to huge migration of population (mostly from rural areas and small towns to

big towns) and inclusion of newer rural areas in the nearest urban settings, apart from natural

growth of urban population. The majority of towns and cities have no sewerage and sewage

treatment services. Many cities have expanded beyond municipalities, but the new urban

agglomerations remain under rural administrations, which do not have the capacity to handle

the sewage. Management of sewage is worse in smaller towns. The sewage is either directly

dumped into rivers or lakes or in open fields.

2.2WASTEWATER GENERATION AND TREATMENT

It is estimated that about 38,254 million litres per day (MLD) of wastewater is generated in

urban centres comprising Class I cities and Class II towns having population of more than

50,000 (accounting for more than 70 per cent of the total urban population). The municipal

wastewater treatment capacity developed so far is about 11,787 MLD, that is about 31 per

cent of wastewater generation in these two classes of urban centres. The status of wastewater

generation and treatment capacity developed over the decades in urban centres. In view of

the population increase, demand of freshwater for all uses will become unmanageable. It is

estimated that the projected wastewater from urban centres may cross 120,000 MLD by 2051



and that rural India will also generate not less than 50,000 MLD in view of water supply

designs for community supplies in rural areas. However, wastewater management plans do

not address this increasing pace of wastewater generation.

Central Pollution Control Board (CPCB) studies depict that there are 269 sewage treatment

plants (STPs) in India, of which only 231 are operational, thus, the existing treatment

capacity is just 21 per cent of the present sewage generation. The remaining untreated sewage

is the main cause of pollution of rivers and lakes. The large numbers of STPs created under

Central Funding schemes such as the Ganga Action Plan and Yamuna Action Plan of

National River Action Plan are not fully operated.

The development process in India is gaining momentum and the rural population which is

devoid of basic infrastructural facilities will have to be given parity in terms of water supply

and sanitation. This process of change is likely to generate huge volume of wastewater in

rural areas as well. It would be appropriate to design water and wastewater management

plans optimally so that competing pressures on water resources can be eased.

There is a need to plan strategies and give thrust to policies giving equal weightage to

augmentation of supplied water as well as development of wastewater treatment facilities,

recycling, recovery, recharging, and storage. The future of urban water supply for potable

uses will depend majorly on efficient wastewater treatment systems, as the treated wastewater

of upstream urban centres will be the source of water for downstream cities.

2.3 WASTEWATER TREATMENT TECHNOLOGIES

Wastewater Treatment Plant is a facility designed to receive the waste from domestic,

commercial, and industrial sources and to remove materials that damage water quality and

compromise public health and safety when discharged into water receiving systems. The

principal objective of wastewater treatment is generally to allow human and industrial

effluents to be disposed off without danger to human health or unacceptable damage to the

natural environment.

Conventional Wastewater Treatment Processes

Conventional wastewater treatment consists of a combination of physical, chemical, and

biological processes and operations to remove solids, organic matter, and sometimes,

nutrients from wastewater.



Preliminary Treatment

The objective of preliminary treatment is the removal of coarse solids and other large

materials often found in raw wastewater. Removal of these materials is necessary to enhance

the O&M of subsequent treatment units. Preliminary treatment operations typically include

coarse screening, grit removal, and, in some cases, communication of large objects.

Primary Treatment

The objective of primary treatment is the removal of settle able organic and inorganic solids

by sedimentation, and the removal of materials that will float (scum) by skimming.

Secondary Treatment

The objective of secondary treatment is the further treatment of the effluent from primary

treatment to remove the residual organics and suspended solids. In most cases, secondary

treatment follows primary treatment and involves the removal of biodegradable dissolved 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 in the wastewater, thereby producing more

microorganisms and inorganic end-products (principally CO2, NH3, and H2O). Several

aerobic biological processes are used for secondary treatment differing primarily in the

manner in which oxygen is supplied to the microorganisms and in the rate at which

organisms metabolize the organic matter. Common high-rate processes include the activated

sludge processes, trickling filters or bio-filters, oxidation ditches, and rotating biological

contractors (RBCs). A combination of two of these processes in series (for example bio-filter

followed by activated sludge) is sometimes used to treat municipal wastewater containing a

high concentration of organic material from industrial sources.

2.4 BIOFLTRATION

Filtration is one of the most important treatment processes used in water and wastewater

treatment. In water treatment, it is used to purify the surface water for potable use whereas in

wastewater treatment, the main purpose of filtration is to produce effluent of high quality so

that it can be reused for various purposes.

Any type of filter with attached biomass on the filter-media can be defined as a biofilter. It

can be the trickling filter in the wastewater treatment plant, or horizontal rock filter in a

polluted stream, or granular activated carbon (GAC) or sand filter in water treatment plant.



Biofilter has been successfully used for air, water, and wastewater treatment. It was first

introduced in England in 1893 as a trickling filter in wastewater treatment [Metcalf and Eddy,

1991], and since then, it has been successfully used for the treatment of domestic and

industrial wastewater. Originally, biofilter was developed using rock or slag as filter media,

however at present, several types and shapes of plastic media are also used. There are a

number of small package treatment plants with different brand names currently available in

the market in which different shaped plastic materials are packed as filter media and are

mainly used for treating small amount of wastewater (e.g. from household or hotel).

Irrespective of its different names usually given based on operational mode, the basic

principle in a biofilter is the same: biodegradations of pollutants by the micro-organisms

attached onto the filter media.

Use of a biofilter in drinking water treatment (especially with granular activated carbon as

filter media) was felt necessary only after the discovery of the re-growth of micro organisms

in water distribution pipe lines few decades ago. It has been observed that the inner surface of

water distribution pipelines carrying potable water is coated with layers of biomass in few

years of service period [Van der Kooij et al., 1982; LeChevallier and Lowry, 1990; Bouwer

and Crowe, 1988]. The biodegradable organic matter (BOM), NH4+, Fe

2+, Mn

2+, NO

2,

dissolved H2 and several other reduced species of sulfur are the most pertinent components

that can cause bacterial regrowth on the water distribution pipelines [Rittmann and Huck,

1989]. Due to the “regrowth” of the microbial mass in the pipelines, the drinking water is

considered biologically not stable. Even though there is no direct evidence of its instant

health and hazardous side effects, use of such drinking water in long run cannot be assured to

be safe. Besides the by-products of chlorine disinfection, disinfections by-products (DBPs)

are often carcinogenic and harmful.

The biological treatment especially by granular activated carbon (GAC) biofilter has been

found effective in removing organic substances that can cause the microbial growth in the

pipe lines, and is normally recommended to be included in the water treatment processes after

ozonation [Bouwer and Crowe, 1988; Hozalski et al., 1995; Ahmad and Amirtharajah, 1998;

Carlson and Amy, 1998]. Bacterial masses attached onto the filter media as biofilm oxidize

most of the organics and use it as an energy supply and carbon source. Removal of the

organic matters not only impairs microbial re-growth but also reduces taste and odor, the

amount of organic precursor (available to form disinfection by-products, corrosion potential)



and other micro-pollutants of health and aesthetic concern. Because of its wide range of

application, many studies have been done on biofiltration system in last few decades .

However, theoretically it is still difficult to explain the behaviour of a biofilter. The growth of

different types of microorganisms in different working conditions makes it impossible to

generalize the microbial activities in a biofilter. The biofilters operated at different filtration

rates and influent characteristics can have diverse efficiency for different target pollutants.

Besides, due to some of the operational drawbacks of the biofilter such as performance

fluctuation, maintenance of biomass, and disinfection adequacy of the biofilter effluent,

research on biofiltration process has become imperative

2.5 APPLICATIONS OF BIOFILTER

Biofilter can be employed either as a primary treatment unit or secondary unit in the

wastewater treatment system. When the amount of wastewater is relatively small and hence a

complete treatment can be accomplished in one tank (package treatment plant) which has

been partitioned for pretreatment, biofiltration, and sedimentation processes (Fig. 7). Various

types and shapes of plastic materials are used as the biofilter media. This type of package

treatment plant is widely used to treat on-site household and industrial waste-water. Biofilter

has successfully been used as a trickling filter for the domestic wastewater treatment. It can

be used with and without other biological treatment processes depending on the

characteristics of the influent, and the effluent quality requirement. The rock, slag or plastic

materials are used as the trickling biofilter media.

FIG. 2.1: Schematics of the package biofiltration system for the treatment of

wastewater.



2.6 SUBMERGED AERATED FILTERS

Submerged Aerated Filter (SAF) and Biological Aerated Flooded Filter (BAFF) technologies

are similar, i.e. the media is submerged and air is supplied via blowers to maintain the

biomass on the medium surface, except that SAF systems do not employ back washing but

require a sedimentation tank for solids separation and removal. The medium used is normally

modular plastic, 3-6 m in depth, which reduces head loss and prevents blockages (Fig. 2.2).

The surface area of the modular medium is significantly lower than the granular media used

in BAFFs, resulting in lower solids retention which eliminates back washing. Typical specific

surface areas of SAF modular media varies from 250-350 m /m , with the higher surface

areas are from 250-350 m /m , with the higher surface areas are being used for nitrification.

Air is supplied by diffusers and although only process air is required some designs

incorporate the provision of air scouring at similar pressures as used during back washing of

BAFFs. This provides greater control of sludge removal as otherwise the biomass sloughs off

in large clumps causing problems during final settlement.

Submerged aerated filters are packaged units designed for typical organic loadings of 3 kg

BOD/m.d and hydraulic loadings of 2-8 m /m.h. Oxygen requirements and sludge production

rates are similar to those for BAFF. If a 95 percentile effluent quality <25 mg/l BOD and 35

mg/l suspended solids is required, then tertiary treatment must be used. Simple to operate and

robust, SAFs are ideal packaged units for small treatment plants (<5,000 PE). They require

little maintenance making them suitable for unmanned and isolated works. SAF units are

used to up rate existing works, for example by reducing the loads to existing percolating

filters in order to promote nitrification. The period for set up is much shorter than for

activated sludge, being only 3-8 d for BOD removal, making them very flexible in terms of

expanding presented treatment capability. Schlegal and Teichgraber (2000) describe the

successful application of SAFs for the pre-treatment of industrial waste waters including

waste waters from food processing, carpet dyeing, pharmaceutical and tar processing

factories. An up flow SAF system was used by Timur (2001) for denitrification with

maximum denitrification rates achieved at COD:NO3-N ratios of 5-6, independent of

hydraulic loading rate or influent NO3-N concentrations Denitrification followed half-order

kinetics, with removal efficiencies of 71-99% reported. An Up-flow Anaerobic/Aerobic

Fixed Bed (UA/AFB) combined reactor was used by Moosavi et al. (2005) for simultaneous

Anaerobic/Aerobic Fixed Bed (UA/AFB) combined reactor was used by Moosavi et al.

(2005) for simultaneous mid organics and nutrients removal by using a synthetic wastewater



was prepared in concentrations which were close to those found in municipal waste waters.

The reactor was operated at 5 different HRTs ranging from 5to 24 h, the obtained results

showed that the HRT of 7 h was suitable for simultaneous removal of COD, nitrification and

denitrification. In this HRT efficiencies are 95.4, 94 and 94.5% for COD removal,

nitrification and denitrification, respectively. The reactor did not show good performance in

phosphorus removal.

FIG. 2.2: Schematic diagram of submerged aerated filters in series (IWEM, 2000)

2.7 NATURAL FIBRES

Natural fibres can be defined as bio-based fibres or fibres from vegetable and animal origin

(table 2.1). This definition includes all natural cellulosic fibres (cotton, jute, sisal, coir, fl ax,

hemp, abaca, ramie, etc.) and protein based fibres such as wool and silk. Excluded here are

mineral fibres such as asbestos that occur naturally but are not bio based. Asbestos containing

products are not considered sustainable due to the well known health risk, that resulted in

prohibition of its use in many countries. On the other hand there are manmade cellulose fibres

(e.g. viscose-rayon and cellulose acetate) that are produced with chemical procedures from

pulped wood or other sources (cotton, bamboo). Similarly, regenerated (soybean) protein,

polymer fibre (bio-polyester, PHA, PLA) and chitosan fibre are examples of semi-synthetic

products that are based on renewable resources.



Table 2.1 - Estimated global production volume averages of different natural fi bres (in

million metric tons per year average over the recent years).

2.8 VALUE ADDITION IN FIBRE CONVERSION

Practically everywhere and in all countries natural fibres are produced and used to

manufacture a wide range of traditional and novel products from textiles, ropes and nets,

brushes, carpets and mats, mattresses to paper and board materials. The long fibres are

transformed to threads or yarns that are used to join, connect or attach and to form bonds,

networks or weaves.

The fibre and textiles industries are among the most labour intensive sectors and therefore

stimulate the industrialisation in cheap labour countries. Textiles production is often a major

economic output for these countries.

However, in many of the less developed countries the fibre and textile sectors are still poorly

developed, but offer perspective for socio-economic development. This development should

be sustainable and therefore not at the expense of the environment or exploiting workers. In

the value addition chain of fibre crop production and supply to markets various

environmental impacts can be distinguished. The impact factor on the environment is related

to the production volumes of fibre products and the size of the end-use market.



Cotton is by far the largest fibre crop globally and is reaching almost 25 million tons

production per annum (Table 2.1), accounting for almost 40% of the total textile fibre market.

It is grown in many countries, but the majority of production is coming from China, USA,

India, and Pakistan (see FAO statistics; ICAC; UNCTAD, ITC, WTO). Many sub-Saharan

countries produce substantial quantities of cotton, but lack the local infrastructure and

industry to produce quality export textiles for higher value addition. The global cotton fibre

demand has shown a growth rate of more than 5% in the recent years, in line with the

manmade fibre market expansion.

Other industrial natural fibres are produced in substantially smaller volumes, all together not

exceeding 6 million tons production. These production volumes have stagnated in the last

decades and these fibres are only supplying a few percents of the textile fibre market (2-3%)

(FAO statistics).

Trade markets and exports of most of the natural fibres (Sisal and Henequen, Jute and Kenaf,

Flax and Hemp) have seen a decline in the past decades, which is often attributed to

introduction of cheaper synthetic substitutes. The market for jute bags for transport of

agricultural products, for example, has seen dramatic decline, also due to increased container

shipments. Agricultural twine and ropes is still one of the largest markets for especially sisal,

while the highest fibre grades are used for manufacturing of rugs and home furnishing.

Current innovation on the markets for natural fibre containing (composite) products has

widened the scope of its use and that should go parallel with agro-industrial development.

Then it has the potential to become a major sustainable bio-economic commodity.

The economic value of the fibre crop depends on its end-use market and costs of production.

Fine and long fibres that can be spun into high counts of yarns are most appreciated and

valued. On the other hand homogeneity is prerequisite to efficient processing and high quality

end-products. Lower quality shorter or coarser fibres are converted into nonwoven products,

paper pulp or other materials. The lowest value of fibres is when it is left in the field as mulch

to compost. The value of the end-product is not always reflected in the benefits for the

agricultural production, however. In the production chain from farm to customer many steps

are taken (Fig.2.3) and quality improvement is attained at the cost of substantial losses. By-

products, residues and wastes commonly are not contributing to the value addition. On the

contrary, these may cause environmental pollution or add to costs for disposal.



The environmental impact of natural fibres accordingly also relies on how by-product

management is organized. In principle renewable resources will be fully bio-convertible and

may be reutilised as source for carbon in the form of carbohydrates (sugars), lignin or protein

(nitrogen) and minerals. Often agricultural production utilises only a small part of the total

fixed carbon in the biomass produced or harvested. These wastes can be utilised far better.

For example, only 2-4% of the harvested biomass of sisal is converted to economic value.

The remains from the leaf contains short fibres and soluble sugars that are now commonly

discharged in the environment. Other plant parts (poles and stems) are left in the field or

burned.

FIG. 2.3:The relation between value addition and conversion steps in the fibre chain

Recently, studies have been initiated that are aiming at zero emission models for the sisal

industries and to use this waste biomass for ethanol fermentation purposes or production of

biogas. Additional income from carbon trade (CDM) promotes (foreign) investments in local

environmental and socio-economic improvements.

In bast fibre crops like flax, hemp and jute the yield of waste biomass per ha is relatively low.

Approximately of the stem dry weight is the appreciated long fibre. The woody parts (shives,



hurts, stick) may be applied as light weight construction materials or burnt as (cooking) fuel.

During the transformation from straw to fabric yield losses are considerable. Different grades

of tow and short fibres are released during the scutching and hackling processes that are

better suitable for staple fibre spinning and rope making, for non-wovens and fibre

composites and in non-wood specialty paper pulp production.

Many fibre crops also yield valuable oil seeds as by-products (cotton, kapok, linseed, hemp),

and many oilseed crops yield fibrous residues. For example coir is considered a by-product

from the coconut oil and copra production. Also the wool market may not be the main value

to the sheep farming.

Table 2.2 : Natural fibre major end-markets and by-products for value addition



2.9 NATURAL FIBRE FILTER TO IMPROVE WASTEWATER

TREATMENT

Natural fibres such as flax or coconut could be used to develop a natural fibre filter to

enhance treatment at wastewater treatment plants particularly in rural areas and developing

countries. There is already a lot of knowledge about these fibres, for example flax fibre is

traditionally used by Maori in many different ways, but this knowledge has not been applied

to wastewater treatment. It might also be possible to treat the fibre in some way (eg slightly

charing it) to enhance its performance.

2.10 PREVIOUS WORK DONE

Kudaligama et al., did a study on “ Effect of Bio-brush medium: a coir fibre based biomass

retained on treatment efficiency of an anaerobic filter type reactor”, which reveals that the

efficiency of treatment increased with increase in SSA of the media and proper calibration of

OLR in the reactor.

Kevin M. Sherman et al., did a study on “Introducing a new media for fixed film treatment in

Decentralied Wastewater systems”, which reveals that Quanics .Inc . has patented a product

that combines adavantages of both naturally and artificially occuring media. The product

has successfully passed NSF Standard 40 certification.

Padmini et al., Surface modified Agava sisalana as an adsorbent for removal of nickel from

aqueous solutions- Kinetics and Equilibrium studies. The studies reveals that the Sisal fibre

can be considered to be a cheap and viable adsorbent for the removal of nickel from aqueous

solution

Vinod et al. , did a study on “Studies on natural fibrous material as submerged aerated beds

for wastewater treatment”, which reveals that the maximum percentage reduction of

COD(73%), BOD₅(80%), and Orthophosphate(82%) with increased retention time in both

reactors. The used of natural fibrous materials as fixed bed in WWT shows promising

removal efficiency of organic and nutrients.

Shivakumaraswamy G.R et al., did a study on “Domestic wastewater treatment in reactors

filled with areca husk fibres and pebble bed”, which reveals that Areca husk fibres could be

applied as an alternative medium to gravel bed for packed bed filters for the treatment of

domestic wastewater since removal of COD, BOD and NH₃ were 299,31.5 and 27.89mg/L.



Vinod A.R et al., did a study on “ Treatability studies of selective fibrous packing medias for

sewage treatment”, which reveals that the coconut coir packing density 40kg/mᵌ showed

higher removal efficiency of organic matter and nutrients in comparison to 70kg/mᵌ. Cost

effective and locally available medias such as coconut coir fibres, coffee husk can be used as

an alternative option for sewage treatment.

Gulhaane M.L. et al., did a study on “Performance of the modified multi-media filter for

domestic wastewater treatment”, which reveals that the multi-media maybe considered as

efficient pre-treatment process for wastewater treatment. The media enhance the performance

of treatment system, and this technology is environment friendly and cost effective.

Bharati Sunil et al., did a study on “Coconut coir: A media to treat the wastewater”, which

reveals that naturally available low cost media proves essentially a best option to

industrialists to prevent the environmental pollution. Coconut coir fibre is rich in cellulose

and lignin, having a high specific area and wetting ability factor which are essential for

bacterial adhesion in fixed film processes.



CHAPTER 3

MATERIALS AND METHODOLOGY

In our present study we have checked the feasibility of Agava sisalana and Areca husk fibres

as filter media for wastewater treatment. Wastewater quality analysis have been conducted in

the laboratory for parameters such as BOD, COD, chlorides, nitrates, sulphates.

3.1 MATERIALS

3.1.1 Agava sisalana as a filter media

FIG 3.1: Agava sisalana

Scientific classification

Kingdom: Plantae

Division: Mangnoliophyta

Class: Liliopsida

Order: Asparagales

Family: Agavaceae

Genus: Agave

Species: A. Sisalana



Agave sisalana, is a species of Agave native to southern Mexico but widely cultivated and

naturalized in many other countries. It yields a stiff fibre used in making various products.

The term sisal may refer either to the plant's common name or the fibre, depending on the

context. It is sometimes referred to as "sisal hemp", because for centuries hemp was a major

source for fibre, and other fibre sources were named after it. The sisal fibre is traditionally

used for rope and twine, and has many other uses, including paper, cloth, footwear, hats,

bags, carpets, and dartboards.

Sisal plants, Agave sisalana, consist of a rosette of sword-shaped leaves about 1.5–2 metres

(4.9–6.6 ft) tall. Young leaves may have a few minute teeth along their margins, but lose

them as they mature. The sisal plant has a 7–10 year life-span and typically produces 200–

250 commercially usable leaves. Each leaf contains an average of around 1000 fibres. The

fibres account for only about 4% of the plant by weight. Sisal is considered a plant of the

tropics and subtropics, since production benefits from temperatures above 25 degrees Celsius

and sunshine.

Fibre is extracted by a process known as decortication, where leaves are crushed and beaten

by a rotating wheel set with blunt knives, so that only fibres remain. The production is

typically on large scale, the leaves are transported to a central decortication plant, where

water is used to wash away the waste parts of the leaf. The fibre is then dried, brushed and

baled for export. Proper drying is important as fibre quality depends largely on moisture

content. Artificial drying has been found to result in generally better grades of fibre than sun

drying, but is not always feasible in the developing countries where sisal is produced .Fibre is

subsequently cleaned by brushing. Dry fibres are machine combed and sorted into various

grades, largely on the basis of the previous in-field separation of leaves into size groups.

Traditionally, sisal has been the leading material for agricultural twine (binder twine

and baler twine) because of its strength, durability, ability to stretch, affinity for certain

dyestuffs, and resistance to deterioration in saltwater. Sisal has been utilized as an

environmentally friendly strengthening agent to replace asbestos and fibreglass in composite

materials in various uses including the automobile industry. As extraction of fibre uses only a

small percentage of the plant, some attempts to improve economic viability have focused on

utilizing the waste material for production of biogas, for stockfeed, or the extraction of

pharmaceutical materials.

https://en.wikipedia.org/wiki/Agave

https://en.wikipedia.org/wiki/Fiber

https://en.wikipedia.org/wiki/Hemp

https://en.wikipedia.org/wiki/Rosette_(botany)

https://en.wikipedia.org/wiki/Decorticator

https://en.wikipedia.org/wiki/Baler_twine

https://en.wikipedia.org/wiki/Biogas



3.1.2 Areca husk fibre as a filter media

FIG 3.2: Areca husk

SCIENTIFIC CLASSIFICATION

Kingdom: Plantae

Order: Arecales

Family: Arecaceae

Genus: Areca

Species: A. catechu

Among all the natural fiber-reinforcing materials, areca appears to be a promising material

because it is inexpensive, availability is abundant and a very high potential perennial crop. It

belongs to the species Areca catechu L., under the family palmecea and originated in the

Malaya peninsular, East India. Major industrial cultivation is in East India and other countries

in Asia. The husk of the Areca is a hard fibrous portion covering the endosperm. It constitutes

30–45% of the total volume of the fruit. Areca husk fibers are predominantly composed of

hemicelluloses and not of cellulose. In Table 1 the chemical composition of Areca fibers is

shown along with few known fibers. Areca fibers contain 13 to 24.6% of lignin, 35 to 64.8%

of hemicelluloses, 4.4% of ash content and remaining 8 to 25% of water content. The fibers

adjoining the inner layer are irregularly lignified group of cells called hard fibers and the

portions of the middle layer contain soft fibers.

Selected variety of tender areca was used to study the strength of fiber and to prepare the

composites. Green husks of tender areca were soaked in water for about 4 days. The soaking

process loosens the fibres and fibres can be extracted out easily. The Areca fibres were

separated from the partial dried Areca husk using slow speed hammer mill. Completely dried



and thrashed husks were forced through the cyclone separators repeatedly till the neat fibers

were separated. The dried Areca husk selected randomly among the stock is considered for

the experimentation.

3.2 CHIKKAMAGALURU

Chikkamagaluru is a district of Karnataka.According to 2011 census the chikkamagaluru

district has a population of about 1,20,496 , its population growth rate over the decade 2001-

2011 was -0.28%. The quantity of wastewater being generated is 13.01MLD. The sewage is

discharged from individual residential colonies directly into the open drain, since there is no

under drainage system for the collection and disposal of sewage.

3.3 SAMPLING

Sampling was conducted for every 72 hours for a period of 15 days between 5:30 pm to 6:30

pm. Grab samples were collected in plastic cans rinsed with distilled water. Sample was

collected from the open drain channels, in Jayanagar area of Chikmagalur town and the

treatment process was carried out.

FIG 3.3: Open drainage channel

Samples were analysed for the following parameters:

1. BOD

2. COD

Sampling point



3. Chloride

4. Sulphate

5. Nitrate

6. pH

3.4 METHODOLOGY

FIG 3.4: Cross-section of RC-1 Reactor (Agava sisalana)

FIG 3.5: Cross-section of RC-2 Reactor (Areca husk)

Two different fibrous packing materials used for the present study, Agave sisalana

and Areca husk fibre.



Two reactors used in this study, are made of 6mm glass, having dimensions 45cm

x45cm x60 cm, filled with agave sisalana and areca husk fibres for a known depth of

15 cm.

Reactors are rectangular in shape and fabricated for downflow mode and for batch

operation process.

Diffused aerators are used to maintain the dissolved oxygen level inside both the

reactors.

Accessories such as mesh, Inlet and outlet pipes and taps are used.

Initially to start-up the reactor, dairy sludge obtained from Hassan dairy was mixed

with AIT girls hostel wastewater of ratio 1:1 for seeding.

These reactors were then aerated with diffused air pumps continuously for 7 days for

acclimatization and development of biomass in both the reactors.

After the complete growth of biomass on the surface of fixed beds in both reactors,

known volume (25L) of wastewater is fed through inlet pipe and MLSS is kept

constant at an average in both the reactors.

The initial characteristics of the wastewater used for the study is determined.

The sampling was done after attaining a DO concentration 2.5mg/L in both reactors at

an interval of 24hours up to a contact time of 72 hours.

The parameters such as pH, COD, BOD5, chloride, sulphate, nitrate are analyzed for

the samples coming from the outlet by implementing standard methods for the

Examination of Water and Wastewater, (APHA, AWWA,20th Edition).

3.5 TEST PERFORMED

3.5.1 Biochemical oxygen demand (BOD) test

This process involves the measurement of dissolved oxygen used by the micro organism in

the biochemical oxidation of organic matter.

The permissible for a domestic sewage is as follows:

Strong waste - 400mg/L



Medium waste - 220mg/L

Weak waste - 110mg/L

If sufficient oxygen is available, the aerobic biological decomposition of an organic waste

will continue until all of the waste is consumed. The more or less distinct activities occur.

First, a portion of waste is oxidized to end product to obtain energy for cell maintenance and

the synthesis of new cell tissue. Simultaneously, some of the waste is converted into new cell

tissue using part of the energy released during oxidation. Finally, when the organic matter is

used up, the new cells begin to consume their own cell tissue to obtain energy for cell

maintenance. The third process is called endogenous respiration.

Test procedure

A small sample of the waste water to be tested is placed in a BOD bottle of volume

300ml.

The bottle is then filled with dilution water saturated in oxygen and containing the

nutrients required for biological growth.

The initial DO test is carried out for the sample and the rest of the sample are

incubated for 5 days.

Various dilution ratios (2%, 5%) along with distilled water are taken and the DO test

is performed.

The ranges of BOD can be measured with various dilutions based on percentage

mixture and direct pipetting.

After the bottle is incubated for 5 days at 200 C, the DO concentration is measured

again. The BOD of the sample is the difference in the DO concentration values

expressed in milligrams per liter, divided by the decimal fraction of the sample used.

3.5.2 Chemical oxygen demand (COD) test

This test is used to measure the oxygen equivalent of the organic material in waste water that

can be oxidized chemically using dichromate in the solution.



Test procedure

A known volume of the sample is taken in a condenser flask to which a known

amount of mercuric sulphate and potassium dichromate is added.

Acid reagent is added and is kept in condenser. It is then digested for 1hr at 1500

C

and after cooling the mixture is made up to 150ml by using distilled water.

A known volume is taken in a conical flask and to this ferroin indicator is added.

This is titrated against ferrous ammonium sulphate of 0.1 normality.

The change in the colour from greenish to wine red indicates the end point.

3.5.3 Test for nitrate

Test procedure

This test is usually carried out using a spectrophotometer.

The stored program number for nitrate (335) is entered and it is adjusted for 500nm

wavelength.

The sample cell is filled with known volume of sample and nitrovar sachet is added to

it.

A 5 minute reaction period is allowed.

After the reaction time the prepared sample is kept into the cell and the display shows

the reading.

3.5.4 Test for sulphate

Test procedure

The program number for sulphate (680) is entered and it is adjusted for 450nm

wavelength.

The cell is filled with the sample.

Sulphavar reagent is added to the cell and a reaction period of 5 minutes is allowed.

After this the cell is placed inside the instrument and the readings are noted.

3.5.5 Test for chlorides

Chloride concentration can be determined by Mohr’s method, titration with standard silver

nitrate solution in which silver chloride is precipated at first. The end titration is indicated by

formation of red silver chromate from excess of AgNo3 and potassium chromate used as an

indicator in neutral to slightly alkaline solution.



Test procedure

100ml of sample is taken in a conical flask.

The pH is adjusted between 7 and 8 either with sulphuric acid or sodium hydroxide

solution.

Add 1ml of potassium chromate to get light colour.

Titrate with standard silver nitrate till colour changes from yellow to brick red.

Note the volume of silver nitrate added.



CHAPTER 4

RESULTS AND DISCUSSIONS

4.1 TABULATIONS AND GRAPHS

Table 4.1: Removal efficiency using 15cm Agava sisalana filter bed

FIG 4.1: Represention of variation of pH in 15cm Agava sisalana and Areca husk filter

beds.

7.44

7.46

7.48

7.5

7.52

7.54

7.56

7.58

7.6

7.62

1 2 3 4 5 6 7

pH agava

pH areca

PARAMETERS

INITIAL

15 cm depth AGAVA SISALANA (trial 1)

1st

Day

Removal

Efficiency (%)

2nd

Day

Removal

Efficiency(%)

3rd

Day

Removal

Efficiency(%)

BOD(mg/L) 240 179 25.4 139 42 105 56.2

COD(mg/L) 305 222 27.2 175 42.6 133 56

Chloride(mg/L) 25 21 16 17 32 13 48

Sulphate(mg/L) 1.5 1.1 26.6 0.93 38 0.8 46.6

Nitrate(mg/L) 1.3 0.9 30.7 0.69 46.92 0.6 53.8

pH 7.5 7.6 7.5 7.5



FIG 4.2: Removal efficiency using 15cm Agava sisalana filter bed

Table 4.1 and figure 4.2 represents the values of BOD, COD, chloride, sulphate and nitrate

as 240, 305, 25, 1.5 and 1.3 mg/l respectively. After 24 hours of contact period their removal

efficiency was found to be 25.4%, 27.2%, 16%, 26.6% and 30.7% respectively, similarly

after 48 hours it was found to be 42%, 42.6%, 32%, 38% and 46.92% respectively and at the

end of 72 hours it was found to be 56.2%, 56%, 48%, 46.6% and 53.8% respectively and the

figure 4.1 shows that the pH was found to be constant throughout the contact period of 72

hours.

Table 4.2: Removal efficiency using 15cm Areca husk filter bed

PARAMETERS

INITIAL

15 cm depth ARECA HUSK (trial 1)

1st

Day

Removal

Efficiency(%)

2nd

Day

Removal

Efficiency(%)

3rd

Day

Removal

Efficiency(%)

BOD(mg/L) 240 167 30.4 134 44.1 115 52.08

COD(mg/L) 305 209 31 169 43 146 52

Chloride(mg/L) 25 22 12 18 28 14 44

Sulphate(mg/L) 1.5 1.2 20 1.03 31.3 0.9 40

Nitrate(mg/L) 1.3 0.97 25.3 0.75 42.3 0.65 50

pH 7.5 7.56 7.6 7.5

0

10

20

30

40

50

60

BOD COD CHLORIDE SULPHATE NITRATE

%R

em

ova

l Eff

icie

ncy

Parameters in mg/l

15cms depth Agava sisalana (trail 1)

DAY 1

DAY 2

DAY 3



FIG 4.3: Removal efficiency using 15cm Areca husk filter bed


as 240, 305, 25, 1.5 and 1.3 mg/l respectively. After 24 hours of contact period their removal

efficiency was found to be 30.4%, 31%, 12%, 20% and 25.3% respectively, similarly after 48

hours it was found to be 44.1%, 43%, 28%, 31.3% and 42.3% respectively and at the end of

72 hours it was found to be 52.08%, 52%, 44%, 40% and 50% respectively and figure 4.1

shows that the pH was found to be constant throughout the contact period of 72 hours.


0

10

20

30

40

50

60

BOD COD CHLORIDESULPHATENITRATE

% R

emo

va

l E

ffic

ien

cy

Parameters in mg/l

15cm depth Areca husk (trail 1)

DAY 1

DAY 2

DAY 3

PARAMETERS

INITIAL

15 cm depth AGAVA SISALANA (trial 2)

1st

Day

Removal

Efficiency (%)

2nd

Day

Removal

Efficiency(%)

3rd

Day

Removal

Efficiency(%)

BOD(mg/L) 140 99 29.2 87 37.8 75 46.4

COD(mg/L) 179 124 30 107 40.2 95 46.9

Chloride(mg/L) 61.49 42 31.9 39 36.06 32 47.5

Sulphate(mg/L) 1 0.68 32 0.42 58 0.21 79

Nitrate(mg/L) 1 0.57 43 0.11 89 NIL 100



FIG 4.4: Representation of variation of pH in 15cm Agava sisalana and Areca husk

filter beds.


Table 4.3 and figure 4.5 represents the values of BOD, COD, chloride, sulphate and nitrate as

140, 179, 61.49, 1 and 1 mg/l respectively. After 24 hours of contact period their removal

efficiency was found to be 29.2%, 30%, 31.1%, 32% and 43% respectively, similarly after 48

hours it was found to be 37.8%, 40.2%, 36.06%, 58% and 89% respectively and at the end of

72 hours it was found to be 46.4%, 46.99%, 47.5%, 79% and 100% respectively and figure

4.4 shows that the ph was found to be constant throughout the contact period of 72 hours

7.4

7.45

7.5

7.55

7.6

7.65

7.7

7.75

1 2 3 4 5 6

pH agava

pH areca

0

20

40

60

80

100

120

BOD CODCHLORIDESULPHATENITRATE

% R

emo

va

l E

ffic

ien

cy

Parameters in mg/l

15 cms depth Agava sisalana (trail 2)

DAY 1

DAY 2

DAY 3






140, 179, 61.49, 1 and 1 mg/l respectively. After 24 hours of contact period their removal

efficiency was found to be 27.8%, 29.8%, 31.1%, 43% and 46% respectively, similarly after

48 hours it was found to be 36.4%, 37.9%, 40.9%, 63% and 88% respectively and at the end

of 72 hours it was found to be 45%, 46.2%, 44.2%, 79% and 100% respectively and figure

4.4 shows that the pH was found to be constant throughout the contact period of 72 hours.

0

20

40

60

80

100

120

BOD CODCHLORIDESULPHATENITRATE

% R

emo

va

l E

ffic

ien

cy

Parameters in mg/l

15cm depth Areca husk (trail 2)

DAY 1

DAY 2

DAY 3

PARAMETERS

INITIAL


1st

Day

Removal

Efficiency(%)

2nd

Day

Removal

Efficiency

3rd

Day

Removal

Efficiency(%)

BOD(mg/L) 140 101 27.8 89 36.4 77 45

COD(mg/L) 179 125.5 29.8 111 37.9 96.2 46.2

Chloride(mg/L) 61.49 42 31.1 36 40.9 34 44.2

Sulphate(mg/L) 1 0.57 43 0.37 63 0.21 79

Nitrate(mg/L) 1 0.54 46 0.12 88 NIL 100




PARAMETERS

INITIAL

30 cm depth AGAVA SISAANA (trial 1)

1st

Day

Removal

Efficiency(%)

2nd

Day

Removal

Efficiency(%)

3rd

Day

Removal

Efficiency(%)

BOD(mg/L) 320 208 35 189 40.9 120 62.5

COD(mg/L) 398 260 34.6 237 40.4 151 62

Chloride(mg/L) 70 49 30 37 47.1 27 61.4

Sulphate(mg/L) 1 0.44 56 0.01 99 NIL 100

Nitrate(mg/L) 1 0.68 32 0.32 68 0.1 90

pH 7.7 7.6 7.7 7.5

FIG 4.7: Representation of variation of pH in 30cm Agava sisalana and Areca husk

filter beds.

7.4

7.45

7.5

7.55

7.6

7.65

7.7

7.75

1 2 3 4 5 6 7

pH agava

pH areca





320, 398, 70, 1 and 1 mg/l respectively. After 24 hours of contact period their removal

efficiency was found to be 35%, 34.6%, 30%, 56% and 32% respectively, similarly after 48

hours it was found to be 40.9%, 40.4%, 47.1%, 99% and 68% respectively and at the end of

72 hours it was found to be 62.5%, 62%, 61.4%, 100% and 90% respectively and figure 4.7

shows that the pH was found to be constant throughout the contact period of 72 hours.


PARAMETERS

INITIAL

30cm depth ARECA HUSK (trial 1)

1st

Day

Removal

Efficiency(%)

2nd

Day

Removal

Efficiency(%)

3rd

Day

Removal

Efficiency(%)

BOD(mg/L) 320 221 30.9 177 44.68 125 61

COD(mg/L) 398 276 30.6 220 4407 157 60.5

Chloride(mg/L) 70 44 37.1 38 45.7 29 58.5

Sulphate(mg/L) 1 0.58 42 0.02 98 NIL 100

Nitrate(mg/L) 1 0.59 41 0.29 71 0.12 88

Ph 7.7 7.7 7.6 7.6

0

20

40

60

80

100

120

BOD CODChlorideSulphateNitrateRem

oval

Eff

icie

ncy

(%

)

Parameters (mg/L)

30cm depth Agava sisalana (trail 1)

Day 1

Day 2

Day 3





as 320, 398, 70, 1 and 1 mg/l respectively. After 24 hours of contact period their removal

efficiency was found to be 30.9%, 30.6%, 37.1%, 42% and 41% respectively, similarly after

48 hours it was found to be 44.68%, 44.7%, 45.7%, 68% and 71% respectively and at the

end of 72 hours it was found to be 61%, 60.5%, 58.5%, 100% and 88% respectively and

figure 4.7 shows that the pH was found to be constant throughout the contact period of 72

hours.


PARAMETERS

INITIAL

30cm depth AGAVA SISALANA (trial 2)

1st

Day

Removal

Efficiency(%)

2nd

Day

Removal

Efficiency (%)

3rd

Day

Removal

Efficiency(%)

BOD(mg/L) 335 219 34.6 139 58.5 110 67.1

COD(mg/L) 419 271 35.3 170 59.4 133 68.2

Chloride(mg/L) 73 51 30.1 39 46.5 27 63

Sulphate(mg/L) 1.02 0.32 68.6 0.01 99 NIL 100

Nitrate(mg/L) 1.1 0.47 57.2 0.2 81.8 NIL 100

Ph 7.6 7.6 7.7 7.6

0

20

40

60

80

100

120

BOD COD ChlorideSulphateNitrate

Rem

oval

Eff

icie

ncy

(%

)

Parameters (mg/L)

30 cm depth Areca husk (trial 1)

Day 1

Day 2

Day 3



FIG 4.10: Represention of variation of pH in 30cm Agava sisalana and Areca husk filter

beds.



were 335, 419, 73, 1.02 and 1.1 mg/l respectively. After 24 hours of contact period their

removal efficiency was found to be 34.36%, 35.3%, 30.1%, 68.6% and 57.2% respectively,

similarly after 48 hours it was found to be 58.5%, 59.4%, 46.5%, 99% and 81.8%

respectively and at the end of 72 hours it was found to be 67.1%, 68.2%, 63%, 100% and

100% respectively and figure 4.10 shows that the pH was found to be constant throughout the

contact period of 72 hours.

7.4

7.45

7.5

7.55

7.6

7.65

7.7

7.75

1 2 3 4 5 6

pH agava

pH areca

0

20

40

60

80

100

120

BOD COD Chloride Sulphate NitrateRem

oval

effi

cien

cy (

%)

Parameters (mg/L)

30 cm depth Agava (trial 2)

Day1

Day 2

Day 3




PARAMETERS

INITIAL


1st

Day

Removal

Efficiency(%)

2nd

Day

Removal

Efficiecy(%)

3rd

Day

Removal

Efficiency(%)

BOD(mg/L) 335 227 32.2 155 53.7 119 64.4

COD(mg/L) 419 280 33.1 191 54.4 145 65.3

Chloride(mg/L) 73 50.5 30 41 43.8 27.5 62.3

Sulphate(mg/L) 1.02 0.4 60.7 0.03 97 NIL 100

Nitrate(mg/L) 1.1 0.51 53.6 0.1 90.9 NIL 100

pH 7.6 7.5 7.6 7.6



were 335, 419, 73, 1.02 and 1.1 mg/l respectively. After 24 hours of contact period their

removal efficiency was found to be 32.2%, 33.3%, 30%, 60.7% and 53.6% respectively,


respectively and at the end of 72 hours it was found to be 64.4%, 65.3%, 63.2%, 100% and

100% respectively and figure 4.10 shows that the pH was found to be constant throughout

the contact period of 72 hours.

0

20

40

60

80

100

120

BOD COD Chloride Sulphate Nitrate

Rem

oval

Eff

icie

ncy

(%

)

Parameters (mg/L)

30 cm deth Areca husk (trial 2)

Day 1

Day 2

Day 3



Table 4.9:Removal efficiency using combined filter beds

PARAMETERS

INITIAL

COMBINED TREATMENT

1st

Day

Removal

Efficiency(%)

2nd

Day

Removal

Efficiency(%)

3rd

Day

Removal

Efficiency(%)

BOD(mg/L) 420 225 46.4 160 61.9 97 77

COD(mg/L) 529 280.2 47 195 63.1 120 78

Chloride(mg/L) 81 46 43.2 37 54.3 19 76.5

Sulphate(mg/L) 1 0.45 55 0.01 99 NIL 100

Nitrate(mg/L) 1.02 0.6 41.2 0.1 90.1 NIL 100

Ph 7.6 7.5 7.6 7.6

FIG 4.13: Representation of variation of pH in combined filter bed.

7.44

7.46

7.48

7.5

7.52

7.54

7.56

7.58

7.6

7.62

1 2 3 4 5 6

pH of combined

pH of combined



FIG 4.14: Removal efficiency using combined filter beds.


were 420, 529, 81, 1 and 1.02 mg/l respectively. After 24 hours of contact period their

removal efficiency was found to be 46.4%, 47%, 43.2%, 55% and 41.2% respectively,


respectively and at the end of 72 hours it was found to be 77%, 78%, 76.5%, 100% and 100%

respectively and Figure 4.13 shows that the pH was found to be constant throughout the

contact period of 72 hours.

4.2 COMPARISON OF AGAVA SISALANA AND ARECA HUSKFIBRES

FIG 4.15: Comparison of BOD and COD Removal Efficiency (15cm depth)

0

20

40

60

80

100

120

BOD COD Chloride Sulphate Nitrate

Rem

oval

Eff

icie

ncy

(%

)

Parameters (mg/L)

Mixed media treatment

Day 1

Day 2

Day 3

49

50

51

52

53

54

55

56

57

AGAVA ARECA AGAVA ARECA

Rem

oval

effi

cien

cy(%

)

Parameters

3rd day removalefficiency

BOD

BOD

COD

COD



FIG 4.16: Comparison of BOD and COD Removal Efficiency (15cm depth)

FIG 4.17: Comparison of BOD and COD Removal Efficiency (30 cm depth)

44

44.5

45

45.5

46

46.5

47

47.5


Rem

ov

al

effi

cien

cy(%

)

Parameters


BOD

BOD

COD

COD

62

63

64

65

66

67

68

69


Re

mo

val E

ffic

ien

cy(%

)

Parameters


BOD

BOD

COD

COD



FIG 4.18: Comparison of BOD and COD Removal Efficiency (30 cm depth)

Figure 4.15, figure 4.16, figure 4.17, figure 4.18 shows the comparison study of Agava

sisalana and Areca husk fibres. It can be seen that the removal efficiency of BOD and COD

using Agava sisalana fibre is found to be higher than Areca husk fibre in the above figures.

4.3 COST ANALYSIS

Table 4.10: Cost analysis of Agava sisalana and Areca husk fibre

Aerators: Four numbers of aerators were used having capacity: 2x1.5 litres/minute, power:

4W, volt: 220-240V, frequency: 50 Hz and costing Rs.150 each. Therefore the cost for

treating 25 litres of wastewater using Agava sisalana and Areca husk fibres in the submerged

aerated bed is found to be Rs.79.

62

63

64

65

66

67

68

69


Re

mo

val E

ffic

ien

cy(%

)

Parameters


BOD

BOD

COD

COD

Characteristics processing

fees

labour fees transportation

charges

total

cost

Agava sisalana(4kg) 20/- 50/- 50/- 120/-

Areca husk(4kg) - 20/- 50/- 70/-



CHAPTER 5

CONCLUSIONS AND RECOMMENDATIONS

5.1 CONCLUSIONS

From this study the following conclusions are drawn:

1. Considerable reduction in BOD, COD, nutrients such as nitrates, sulphates, chlorides

were achieved.

2. The removal efficiency of BOD and COD by using Agava as filter media was found

to be 56.2% and 56% respectively, for 15 cm depth which was higher than that of

Areca which was found to be 52.08% and 52% respectively.

3. The removal efficiency of BOD and COD by using Agava as filter media was found

to be 67.1% and 68.3% respectively, for 30 cm depth which was higher than that of

Areca which was found to be 61% and 61.5% respectively.

4. The removal efficiency for BOD and COD were found to be 77% and 78%

respectively, when both the filter medias were combined.

5. The operation trouble faced during the study was foul odour emission due to the early

decomposition of the fibers.

6. The cost of Areca fibers used for the treatment of 25liters of wastewater was about

Rs.70, which is economical than compared to Agava fibres which costs about Rs.120.

However the treatment efficiency of Agava was found to be higher than that of Areca

fibres.

7. The treated wastewater can be used for gardening and other domestic purposes like

washing and cleaning purposes.

8. The spent fibres were rich in nutrient values and can be used as a organic manure.

5.2 RECOMMENDATIONS

Since both the fibres, Agava sisalana and Areca husk is economically viable and that their

treatment efficiency is high, it can also be used for treating large quantity of domestic

wastewater and industrial wastewater. The spent fibres after the treatment having a high

fertiliser value can be used for agriculture purpose.



PLATES

PLATE 1: INITIAL SET-UP

PLATE 2: DIARY SLUDGE IN BALL FORM



PLATE 3: DIARY SLUDGE IN SLURRY FORM

PLATE 4: SEEDING ( Sludge and wastewater ratio(1:1) for 15cm depth

fibres)



PLATE 5: SETUP SHOWING 30cm DEPTH FIBRES

PLATE 6: MIXED MEDIA WITH 30cm DEPTH



REFERENCES

1. Gulhane M.L., Yadav P.G.,associate professor, student, “Performance of the modified

multi – media filter for domestic wastewater treatment”, Proceedings of 3rd IRF

International Conference, 10th May-2014, Goa, India, ISBN: 978-93-84209-15-5.

2. Helen Kalavathy, Lima Rose Miranda and Padmini. E, dept of Chemical Engineering,

A.C.Tech, Anna University, Chennai, “Surface modified Agave sisalana as an adsorbent

for the removal of nickel from aqueous solutions- Kinetics and Equilibrium studies”, vol.

9, No.2 June 2008 pp.97-104.

3. Husham T. Ibrahim1,2, He Qiang1, Wisam S. Al-Rekabi2 and Yang Qiqi1,

“Improvements in Biofilm Processes for Wastewater Treatment”, Pakistan Journal of

Nutrition 11 (8): 708-734, 2012 ISSN 1680-5194 © Asian Network for Scientific

Information, 2012.

4. Jan E.G, ” Environmental benefits of natural fibre production and use”, Proceedings of

the Symposium on Natural Fibres, van Dam Wageningen University, The Netherlands.

5. Kudaligama K V V S , Thurul W M, Yapa P A J., “Effect of Bio-brush medium: a coir

fibre based biomass retainer on treatment efficiency of an anaerobic filter type reactor”,

Journal of the Rubber Research Institute of Sri Lanka.(2015) 87,15-22.

6. Kevin M. Sherman, “Introducing a new media for fixed-film treatment in decentralized

wastewater systems”, Director of Engineering, Quanics,INC., PO box

1520,CRESTWOOD, KY 40014-1520, Water environment foundation 2006.

7. Mahalingegowda. R.M and Vinod. A.R, dept of environmental engineering, PES College

of Engineering, Mandya, Karnataka, “Studies on natural fibrous materials as submerged

aerated beds for wastewater treatment, Vinod A.R et al./Elixir Pollution 51(2012) 10759-

10762.

8. Mahalingegowda. R.M, Vinod. A.R, Shivakumaraswamy. G.R, Department of Civil

Engineering, PES College of Engineering, Mandya, Karnataka, Department of

Environmental Engineering, PES College of Engineering, Mandya, Karnataka, Karnataka

Urban Water Supply and Sewerage Development Board, Mandya, Karnataka, “Domestic

wastewater treatment in reactors filled with areca husk fiber and pebble bed”,

G.R.Shivakumaraswamy et al./ Elixir Pollution 57 (2013) 14064-14066.



9. Mahalingegowda. R.M, Vinod.A.R, “Treatability studies of selective fibrous packing

medias for sewage treatment”, International journal of civil engineering and technology

(ijciet), Volume 5, Issue 9, September (2014), pp. 65-71.

10. Mrs. Bharati Sunil Shete, Dr. Narendra P. Shinkar ,research scholar; SGBAU, Amravati

Dr. Sau. Kamaltai Gawai Institute of Engineering & Technology, Darapur, Amravati,

Maharashtra, Lecturer department of Civil Engineering, Government Polytechnic, Gadge

Nagar, Amravati, “ Coconut coir: a media to treat the wastewater”, international journal

of pure and applied research in engineering and technology , Bharati Sunil Shete,

IJPRET, 2015; volume 3 (9): 91-97.

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