Sanitation Technologies applicable for India

8/19/2019 Sanitation Technologies applicable for India

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Chapter

Options for Rural sanitation in dierentgeographical and climatic conditions of India

Rakesh Johri, Suneel Pandey

The Energy and Resources Institute, e! "elhi

Introduction

There are several technologies available for disposal ofhuman waste. Certain advance technologies are alsoavailable which may not suit to the rural areas due toits initial high cost, technical knowhow and operation &maintenance issues. Solar- powered toilet and vacuumtoilets are few such examples. t is therefore verycrucial to select a technology based on socio cultural

and economic aspect of user along with hydrogeological and soil of the intended area. The twin pitpour !ush water seal individual household toilet aresuccessfully constructed and used in ndia. "io toilet ispromoted mostly by institutions.

The cost of the individual toilet varies from #s.$% to

'( and it will also depend upon the local conditionsincluding availability of material etc.

)owever, it is very critical to choose suitabletechnology for disposal of )uman excreta. There areseveral technological options available based on thehydro geological condition of the region. *ll sanitationtechnologies can be described as either wet or dry. Thewet technologies re+uire water to !ush faeces. The


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!ush toilet is connected to a leach pit, septic tank orsewer. The dry technologies do not re+uire water for!ushing. The traditional pit latrines, ventilated

improved pits are few examples of dry latrines. Thefactors that in!uence the selection of communitysanitation technology are enumerated in Table $below-

Table $ actors in!uencing selection of toilettechnology

#actors of general

rele$ance#actors speci%cally

rele$ant to O&'

() Technical factors

/esign preference

0substructure, !oor slab,s+uatting or raised seat,

superstructure12

Technical standards and

expected lifetime of the

technology2

*vailability of

construction materials2

Cost of construction.

3&4 re+uirements2

5ase of access2 6se of decomposed

waste2

7it-emptying techni+ue.

%. En$ironmental factors


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Soil texture, stability,

permeability2

8roundwater level2 Control of environmental

pollution2

*vailability of water2

7ossibility of !ooding.

3&4 implications for

environmental

protection2 7rotection against

groundwater

contamination2

7rotection from !ooding.

*) Institutional factors

5xisting national9local

strategies2

#oles and responsibilities

of actors implied2

Training capacity2

*vailability of subsidies

and loans2

*vailability of masons,

carpenters, plumbers,

sanitary workers, pit-emptier and pit-diggers.

7it-emptying services

0municipal9private12

Sewerage maintenance

capacity2

7otential involvement of

the private sector2

:ational budget

allocations for sanitation2

Training and awareness

education2 4onitoring.

+) Community factors


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Social organi;ation

factors role of traditional

leadership, religiousleaders, schoolteachers,

community-based health

workers2

3ther factors population

densities, limited space

for latrines, presence of

communal latrines.

3&4 costs2

3&4 training and

awareness for sanitation2 )ealth awareness and

perception of benes groups2

Social mobili;ation on

hygiene and sanitation

behaviour.

Source -ESCO adaptation of .rikk/ #) and .redero

'), 011*

5very toilet has two ma?or parts-

2i3 Superstructure4 t is basically meant to provideprivacy of the toilet. 4a?or technical inputs are not

re+uired for this component. There may be a widerange of superstructures such as masonry, tinsheets, bamboo mats or readymade


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n this chapter, the discussion focuses on technicaloptions in di@erent climatic conditions with respect tosubstructures. These options based on the hydro-

geological conditions of the area and socio-culturalbehaviour of people, are presented as follows

Option ( "ry latrine for normal soil !ith

lo! !ater ta5le

6IP latrines-

The ventilated improved pit latrine 0A71, is a pit latrinewith a black pipe 0vent pipe1


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igure $ Schematic of A7 Batrine

*dvantages

o Bow costo 5asily built by householdo :o need of watero 5asy to maintaino :o smell and no !ies provided all measure are

taken such


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hand ful


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igure % 7our !ush twin pit toilet designPan and trap8!ater seal

The pan used in the pit toilet has steep slope of %-%D. t may be of ceramic, mosaic or


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Such water seal may be ceramics, mosaic or made of


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vi. t can be easily upgraded and connected to sewerwhenever such facility is available in future

vii. ts maintenance is easy.

;imitations of t!o4 pit pour :ush toilet

a17it toilet 0single or double pit1 is not suitable for highwater table and rocky areas. n high water tableareas, there is change of ground watercontamination. t coastal areas also these toilets arenot suitable at all. urther, due to high water table,

ad?oining soil of the pit becomes saturated andfurther percolation from pit reduces signi


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This model is more suitable for areas where people usewater for ablution. The system consists of % nos. ofchambers connected at the middle. t may be brick-

cement or erro-cement structure. Cost of a erro-cement structure is cheaper than the brick-cementstructure. "ottom of both the chambers are sealed with7CC 07lan Cement Concrete1. /uring the use of thetoilets, human waste comes into


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ollowing provisions are made in this type of toiletdesign

a1nternal si;e .Dmx$.$m

b1)eight of wall is $.H% m from front and $.I( m atback

c1 #oof cover is of 8. Sheet9*sbestos sheetd1Two nos. of leaching pits of internal si;e $.% m and

$.( m depth up to ground level.e1/oors of si;e .IJx$.'I m si;e, % gauge 8.

framed with 4.S thick

f1 Creates no wasteg1/oes not smellh17rovides no place for mos+uitoes to breedi1 Self-contained and can be totally managed by the

family.

".Ecological Sanitation 2Ecosan3 toilet

5cosan toilet is more suitable where people don>t usewater for cleaning and instead, papers, napkins etc. areused for such purpose. 5cological Sanitation is basedon the principal of minimising the loss of nutrients inhuman wastes and using such waste including urine. nthe system, human excreta and urine are collectedseparately in containers. 6rine is used in agriculture

land directly, whereas excreta are stored for J monthsor so, to degrade it and its use in agriculture 0igure (1.


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igure ( Bayout of ecosan toilet with provision of separate collection of urine and night soil

n ndian conditions, due to cultural aspect 5cosansystem does not


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around ( cubic feet 0cft1 of biogas would be producedper day and minimum re+uirement of biogas is aboutG cft for cooking for % meals in a day for a small

family. Therefore, biogas can>t meet cookingre+uirement of a small family, if produced from humanwaste of a family. )owever, it can be made viable,when mixed with cattle dung along with human wastes."iogas from dung of at least % nos. of cattle whenmixed with human wastes can cater to the need forcooking for a small family.

igure J Toilet with biogas plant

"esign of 5iogas plant

or a household level biogas plant there are basicallytwo designs 0$1 !oating drum type popularly known asKAC model and 0%1 ixed dome type, popularly knownas /eenbandhu 4odel.


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dung is about $.( cft per kg, i.e. per animal per day$( cft of biogas is produced

ii. rom human waste, per person per day, .'( kg of

waste is produced and gas production from per kg ofhuman wastes is '.J cft. 7er day per person only onecft biogas is produced.

iii. * total amount of biogas of one cum can be producedper day from a family having ( members and % cattleheads.

-tili=ations of 5iogas

3ne cum of biogas per day can be utili;ed in a family asfollows

i. Cooking of ( family members for two times a dayii. 4antle lamps 0% nos1 can be used for J hours per

night. Such mantle lamps give illuminatione+uivalent to G =att bulb at %% volts of

electricityiii. Can run an engine of one )orse 7ower for % hours

"esides biogas, the manure of the plant has good plantnutrient value. t is directly used for agriculturepurpose. /ue to socio cultural issues, generation of biogas from human excreta is not popular option.

") Toilet !ith Septic tank

Septic tank o@ers a preliminary treatment of sewageprior to


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held in these tanks for some prescribed period duringwhich time the suspended solids present in the storagesettle down. The settled sludge and the supernatant

li+uor undergoes anaerobic digestion. The digestionresults in appreciable reduction in the volume of sludgeand reduction organic matter in the li+uid. Totalretention time is maintained for %G-GH hours only.

Septic tank has minimum width of I( mm, minimumdepth of one metre below water level and minimumli+uid capacity of $ litres. or rectangular septic

tank, the length of the tank is % to G times the width.or circular tanks the minimum diameter should not beless than $-'( m and operating depth should not beless than $ m.

igure J Schematic of septic tank based toilet

9d$antages

Septic system provides sanitary method of disposal of

human wastes. There is no foul smell with the system,


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no chance of breeding of mos+uitoes occur with asuitable design septic tank

"isad$antages

• t costs higher• Cleaning of chambers is a cumbersome process. n

rural areas mechanical device to clean septic tankchambers is normally not available. 6nder suchconditions, only manual cleaning is the option.Cleaning manually is an unhygienic and unsocial.

5ven if it is cleaned mechanically, it>s +uite diEcultto dispose it of safely, as it has bad odour andcontaining lot of pathogens.

• Bot of water is re+uired to !ush human wastes.

Therefore, in water scarcity areas, this system isdiEcult to implement

5. .io toilet 2.iodigestor3

"io digester popularly known as "io toilet with the tradename of e-"est 0environment friendly bacterial eEcientsystem for toilets1 has been developed by /#/3,4inistry of /efence, and 8overnment of ndia. Thetechnology was initially developed to address theproblem of human waste disposal in eco-friendly

manner at high altitude areas, including glaciers, forthe ndian *rmy. t is meant for onsite disposal ofhuman waste by anaerobic biodegradation for singlehouse to a colony. The simple yet uni+ue single steptechnology of a bio-digestor consists of three ma?orcomponentsLspecially designed anaerobic microbialconsortium, immobili;ation matrix and fermentation

tank 0igure I1. The microbial consortium has been


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o matrix and Tank "/ for #ail Coach "/ for Single Batrine "/ M #eed "ed for Colony

developed by adaptation and enrichment at lowtemperature and subse+uent bio-augmentation byselected anaerobes belonging to proteolytic, acetogenic

and methanogenic bacteria. The cold active consortiumworks over wide temperature range L(C to G(C,tolerate a few cycles of free;ing and thawing and to anextent detergents and antiseptics. mmobili;ationmatrix accounts for larger bacterial population in thetank, prevent their washout during excess !ushing andprovide resistance to adverse situations like p) and

temperature change, oxygenation, antiseptics anddetergents.


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#igure > 6arious applications for 5iotoilets

9d$antages

Space saving volume is very small L Jlts capacity issuEcient for a family. The desired si;e is $9' rd for afamily and $9$th for a colony when compared to aseptic tank.

Installation: possible by any person for installingbeneath or beside the toilet.

Adaptability: This can be used in any geo-climaticconditions prevalent on this globe such as cold, desert,rocky, water logged areas, hills etc.

Standalone: *s entire treatment happens in situ there isno involvement of any external process.

Customized options: The technology has variousvariants for meeting a broad range of userre+uirements ranging from a single household,community to mobile and disaster management needs.

Zero maintenance: t is a N


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No human intervention *s it does not re+uire anycleaning and maintenance, there is any humanintervention.

"isad$antages

• "iodigestor is to be installed by licensed vendors

authorised by the /#/3. The licensed vendorshave obtained formula for developing microbialconsortium from /#/3 under their license. Thevendor has to ensure +uality control of microbial

consortium.• The cost for individual toilet is high

• )igh level of awareness among the user is

re+uired.

* variant of biodigestor is available with the nameN"iotank cum #eed "edO and is being used at di@erentplaces either connected to a single house hold or in atoilet complex. The biotank is made of cement-brick9#CC or any such material available locally undergroundwith top mounted reed bed system. "ased on gravitywater !ows into the biotank, gets treated and up-!owsinto the reed bed for secondary treatment and out!owsinto the environment or successive use for !ushing,!oor washing or irrigation. The system is also able totreat the grey water generated in the kitchen andbathroom. The biotank does not have any head spaceand complete capacity is utili;ed for fermentation of the waste. )ence, biodigestor technology has all theadvantages available in other treatment systems and

much beyond as desired for sustainable ecological


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sanitation. The most desired result being the +uality of treatment achieved.

The Table % below presents eFuent +uality achieved in

various anaerobic toilet designs.

Ta5le0 Comparison of E?uents

Technology8

Parameter

Septic

Tank

.iodige

stor

.iodige

stor

!ith

Reed

5edp) J.(-I.( J.D-I.% I.-I.( TS

0mg9$m

l1

I(-

$$(

GG-(I '-$(

AS

0mg9$ml1

(-J %-' H-$%

C3/

0mg9B1

$%-

%

(-J I(-$

"3/ (

0mg9B1

'(-( $G-$J %(-'

aecal

coliforms

047:9$

ml1

P'x$J '-

'(

$-$%

Toilet for physically handicapped and old age

people


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or physically challenged persons, s+uatting toilet isnot suitable. t needs a suitably modify commode toiletto suit their needs. Such toilet is also useful to elderly

people or people having knee9?oint pain. or physicallychallenged people using wheel chair, they need aproper space to move with such wheel chair inside thetoilet. * grab bar is needed to provide support to suchpersons while using the toilet. Taking all these factorsin consideration following should be the elements of atoilet for disabled persons

i. 3ne special =.C. should be provided for the use ofhandicapped persons with essential provision ofwash basin near the entrance.

ii. * normal toilet has an average height of around'%-G cms while for handicapped persons toiletshave an average height of about G%-GH cms. 4anypeople who have no disabilities also


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x. The rear wall grab bar shall be 'J inches longminimum and shall extend from the center-line ofthe toilet $% inches minimum on one side and %G

inches minimum on the other sidexi. *dditional options for toilets for handicappedpersons include adding a handicap bidet to washthe backside. Some people are unable to reachthat area with toilet paper or have trouble inwiping.

Operation and 'aintenance of a household toilet

or proper operation and maintenance of a householdtoilets the following do>s and don>ts should beobserved

"o@s and "on@ts to maintain a toilet)

"o@s

i. Bevel of slab on the pit should be '-G inches abovethe ground level, otherwise, rainwater may enterinto the pit. Therefore, do not make pit with coverslab below the ground level.

ii. "oth the pits should be used alternatelyiii. Keep two litters of bucket with water ready in the

toilet for !ushing

iv. 7our little +uantity of water on the pan before it isused. t helps excreta to slide down the trap andpit easily

v. 6se only % mm water seal9pit trap as it re+uiresonly $.(-% litters of water to !ush out excreta.

vi. Toilet should be regularly cleaned.vii. /esludging of pit should be done after % years,

digested human waste in the pit becomesodourless and pathogen free by that time


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viii. 4anure from the pit should not be thrown, ratherused in agriculture as it contains good percentageof plant nutrients

ix. Such digested human waste should be handledwith care and direct hand contact should beavoided9minimi;ed.

"on@ts

i. /on>t use supply water pipe inside the toilet.t results in more use of water for !ushing,

causing decrease in eEciency of pit andhigh hydraulic load may cause ground waterpollution. /on>t use both the pitssimultaneously.

ii. /on>t use any chemicals and detergent toclean the pan. t causes killing of microbesalso, resulting in less degradation of wastes.

iii. /on>t allow kitchen water or bathing waterto enter into toilet

iv. *ny solid material like plastic or small balletc. should not be put into the pan, it blocksthe pit trap making toilet non-functional.

v. n case of blockage of pan due to suchob?ects, it should be taken out manuallyfrom the pan, it may cause more problems,

it stuck in the trap.vi. /on>t throw lighted cigarette butts into the

panvii. /on>t desludge the pit before % years, after

it is


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8ramalaya, Tirichurapalli

Technology option s for urban sanitation in ndia, =ater andSanitation programme 8overnment of ndia

"io digester , /#/3 4inistry of /efence , 8overnment of ndia

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Sanitation Technologies applicable for India