PLANNING & DESIGNING OF LARGE SCALE
POUR·FLUSH LATRINE PROGRAMME
IN URBAN AREAS
BY
A. K. ROY
Resident Manager, UN DP Global Project GL0/78/006
South East Asia, New Delhi.
NOVEMBER, 1981
Views expressed in this paper are those of the author and not reflect the views of the World Bank
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1. Sumrnary
:2, lntroductkm
3, Planning process
4. Evaluation of on-going latrine programme in urban areas
5. Review of existing organisational, managerial, financial capability and legal authorities of the local government
6. House-to-house survey
7. Socio-cultural aspect
8. Proposed technology, its optimisation and study of su!:H~urf~ce polhJtion
9. Pollution aspects
10. Institutional requirements
11. Methodology for construction of household latr!Ms
12. Financial aspect
13. Cost estimate
14. Financing pattern
15. Operation and maintenance
16. Manufacture of pans and traps
17. Annex-1 : ierms of reference-Evaluation of on-going latrine programme
(household and public) in urban areas
18. Annex-2 : Terms of reference-Rehabilitation of scavengers
19. Annex-3 : Suggested provisions in municipal laws
20. Annex-4 : Technology optimisation
21. Annex-5 : Pollution aspect
22. Annex-6 : Functions and responsibilities of organisations
23. Annex-7 : Procedure for construction of household latrines
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Cap
GRP
HOPE
mm
PRAI
PVC
TAG
UNDP
UNICEF
WHO
ACRONYMS USED
Capita
Fibre glass reinforced polyester plastic
High Density Polyethlene
Cubic metre
Millimetre
Planning, Research-cum=Action Institute, lucknow (India)
Polyvinyl chloride
Technology Advisory Group, UNDP Global Project
United Nations Development Programme
United Nations' International Children's Emergency
Fund
World Health Organisation
PLANNING AND DESIGNING OF LARGE SCALE POUR~FLUSH lATRINE
PROGRAMME IN URBAN AREAS
SUMMARY
The UNDP Global Project GL0/78/006 with the assistance Of the Government of India, and the World Bank acting as the executing agency, has recently prepared a Master Plan Report and Feasibility
study of pour-flush waterseal latrines in 110 representative towns with a total population of nearly 5
million (town population ranging between 7,000 to 400,000), having about 800,000 households, in different physical and hydrogeological formations and varying socio-economic conditions in 7 States of India. This is a demonstration project, findings from which would be utilised in preparing similar projects for other towns. Recognising the utility of such a project, the Government of India has now taken up the
preparation of similar projects for another 100 towns in the remaining 14 States of India with assistance
from the UNDP funds for India and with the World Bank acting as the executing agency.
Any large scale latrine programme should necessarily be : hygienically and environmentally safe; technically and scientifically appropriate; socially and culturally acceptable; economically affordable; and
with inbuilt financial and organisational infrastructure, enabling immediate initiation and expeditious implementation of the project The present paper deals exclusively with only one of the eight possible
low-cost sanitation technologies-pourflush waterseal latrines with offset leaching pits-for disposal of
human excreta, which has been adopted in India and is equally applicable in many other countries.
The major inputs to the demonstration projects, based on the Indian experience are: evaluation
of pourflush latrines or any other latrine programme (household or public) and the lessons learnt; rsview
of the organisational, financial, managerial capabilities and legal authorities of the local government in the project towns; house-to-house survey of project towns to ascertain the size of the family, its income,
availability of electricity. water and latrine in the premises and the feasibility of constructing a pour-flush
latrine for deciding the financing pattern to households, optimisation of the proposed technology for least cost solution and studies on sub-surface pollution; institutional requirements for implementation of the
project; methodology for construction of household and public latrines; and the financial aspect of thH project.
PLANNING AND DESIGNING OF lARGE SCALE POUR-FLUSH LATRINE
PROGRAMME IN URBAN AREAS
INTRODUCTION
1. History reveals that once it was an universal practice to defecate directly ehher on the soil or
in flowing streams or stagnant pools. With the passage of time, and the dawn of the modern civilisation,
rapid urbanisation followed. Non-availability of open spaces for defecation and also th3 awarness of
privaGy and convenience, brought the need for household latrines. While in most countries the removal of excreta and its safe disposal from a latrine was a routine practice for the family, without any stigma
attached to it, some countries devised the bucket system in which a particular section of the society made a house-to-house collection of human waste from latrines for its disposal at a particular place. As the world advanced towards industrialisation, the economy of many countries improved and with the spread
of education, health consciousness arose. This resulted in the adoption of water-borne sanitation, making
use of septic tanks or sewerage, with or without sewage treatment. Most of the econo11ic~lly backward
countries continued with the old practice. Only a fraction of the population could afford the facility of
household latrines and these were in most cases the dry and insanitary types. In the densely populated core sector of the old towns in the developing countries, the conventional water-borne sanitation system
has been found to be too costly for adoption. Thus, excreta disposal system in urban areas is in a critical
stage, in particular, in the small and medium towns of these countries. This can, however, be overcome with proper planning and by adopting suitable technological devices for low cost solutions.
2. The global survey (1915) by WHO found that the population living in houses connected to
sewerage system in developing countries dropped from 27 percent to 25 percent between 1970 and 1975.
The house-to house survey (1980) carried out in 7 States of India by the UNDP Global Project (GLOJ78/ 006) in 110 small and medium towns, with nearly 5 million population and 800,000 house-holds having no sewerage system, revealed that on an average, population served with water flush latrines varied in
different States between 11% and 40%, those with dry latrines 7% and 56% and those having no latrines
13% and 78'/,,. The United Nations Conference on Human Settlements (June 1976, Vancouver) stressed the need of priority for the supply of safe water and a hygienic system of waste disposal. The United Nations Water Conference (March 1977, Mardel Plata, Argentina) in which almost all the develo;Jing countries participated, exprec::sed concern over the poor level of service in community water supr: ly and
sanitation. The United Nations in recognition of this urgent need declared 1981-90 as the International Drinking Water Supply and Sanitation Decade to emphasise the world-wide efforts to provide safe drinking water and sanitation to all by 1990.
3. As a contribution to the International Drinking Water Supply and S::mitation Decade, the
World Bank is continuing applied research in an effort to develop techniques for design of low cost water
supply and sanitation systems. These would allow maximum coverage to provide basic needs in the
early years of a project, with progressive up-grading, as more resources become available. In November 1978, the UNDP financed Global Project (GL0 178/006) commenced operations, with the World Bank as
executing agency, to implement these resu Its into actual practice.
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4. fn India, the UNDP Global Project (GL0/78(006) with the assistance of the Government
of India and the World Bank as the executing agency, has recently, prepared a Master Pian Report
including Preliminary Engineering and Feasibility studies for 110 small and medium towns having no sewerage system. The population of these towns, distributed over 7 States of the country, ranges between 7,000 to 400,000 covering a totai population of about 5 million living in 800,000 households. This project provides low-cost pour-flush waterse<:JI latrines with on-site disposal of waste in offset leaching pits to aU households, wherever feasibfe and the remainder by public latrines. Recognising the utility or preparing
such large scale demonstration projects of low-cost latrines, the Government of India has now taken up the preparation of similar projects for another 100 towns in the remaining 14 states with assistance from
the UNDP funds tor India and with the World Bank acting as the executing agency of the Project.
5. The safe disposal of human excreta should be given a high priority as over fifty infections
can be transferred from a diseased person to a healthy one by various direct or indirect routes involving
excreta.* This paper deals 111 particular with the pour~flush watersea! latrines with spot disposal of waste in !~aching pits-its technology, planning and design a large scal.e programme in the urban areas as
experienced in India.
6. Water related sanitation for urban areas snouid be: hygienically and environmentally safe, technically and scientifically appropriate, socially and culturally acceptable; economically affordable and
should be simple in implementing, operating and maintaining. The water related sanitation technology
has been categorised into the following three classes* :
( i ) LOW COST -,Pourflush toilet, pit privy, communal toilet, vacuum--truck cartage, low-cost septic tanks, composting toilets and bucket cartage;
( ii ) MEDIUM COST--Sewered aquaprivy, aquaprivy and Japanese vacuum-truck; and
(iii) HIGH COST-Septic tanks and Sewerage..
7. Seven different technologies under low-cost sanitation have been enumerated above. The· present paper, however, deals exclusively with the pourftush "~Natersea I technology, which has been in use
in India and is equally applicable in the countries of the Indian sub-continent and a!so in many countries of South East Asia where the population at large use water for anal cleansing. Although the technology suggested in this paper cannot be claimed to be pure!y innovative, the Global Project has studied the
various types of such latrines adopted in different countries in the past as well as at present, and has designed an unit of low-cost which is structurally safe and aiso takes care of all precautions to eliminate
health hazards, can be instailed under different physical and hydrogeological conditions, is socially and
culturally acceptable and affordable by the poor (with a certain e!ement of subsidy).
8. Studies and research on the design of a simple waterseal latrine with squatting toilet pan
and suitable trap, disposing the waste into a leaching pit have been going on in India for nearly the last
4 decades, by several agencies such as, the A!l India Institute of Hygiene and Public Health, Calcutta
(1943) in collaboration with Rockefeller Foundation, Research-Cum-Action Project, sponsored by the
Government of India in collaboration with the Ford Foundation (1955 ), the Planning Research-Cum .. Action:
*Appropriate Technology for Water Supply and Sanitation--by John M. Kalbermatten etc., World Bank/December 1980.
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Institute (PRAI) Lucknow assisted by WHO/UNICEF (1958), the Indian Council of Medical Research, the National Environmental Engineering Research Institute, Nagpur and also several social, private and
commercial organisations. Based on these studies, nearly 400,000 pour-flush waterseal latrines have
been constructed in the urban towns of India, many of which are in the densely populated areas.
THE PLANNING PROCESS
9. The preparation of a demonstration project including evaluation and other special investigations detailed below and actual construction of latrine units, to cover a few towns with different physical, hydrogeological ond socio-economic conditions to get a feed back 01 the acceptability, feasibi
lity and affordability of the adopted technology, is a pre-requisite for the planning and implementation of
a large scale pour-flush latrine programme. Findings from such a project coul::l b9 suitably adopted for a
particular local condition without going in for fresh investigations. The major inputs in the demonstration
project are :
( i ) Evaluation of pour-flush or any other latrine programme and th 3 lessons learnt;
( ii) Review of the existing organisational, financial, managerial capabilities and legal authorities
of the local government in the Project towns;
( iii ) House-to-house s&rvey in Project towns;
( iv ) Optimisation of the proposed technology for least cost solution and study on sub-surface
pollution;
( v ) Institutional requirements (includ;ng health education and training); and
( vi ) Methodology for construction of household and public latrines.
EVALUATION OF ONGOING LATRINE PROGRAMME (HOUSEHOLDS AND PUBLIC) IN URBAN AREAS
10. The evaluation of the ongoing household or public water-flush latrine programme, if any,
and in its absence that of the existing latrine situation should be carried out to assess the users' preference
and habits and also that of the non-adopters or those having no household latrines, of different socioeconomic status in varying hydrogeological conditions to identify the constraints and their remedial measures. It would be necessary to determine the promotional or educational activities including financial
assistance needed to encourage acceptance and Government's (at state and local levels) commitment to a pour··flush latrine programme. This study should be carried out at different levels-state, focal and house
holds (See Annex!). The evaluation of the pour-flush latrine programme in urban areas of India c0ncluded
that this type of latrine was acceptable to ali, irrespective of income group3 and were being used regularly wherever they had been installed. The study further revealed that the public latrines were seldom used by permanent inhabitants. It is thus apparent that in view of the multiple problems faced in maintenance
of public latrines, it is economical in the long run to provide a household latrine. wherever feasible, even
if full grant is to be provided.
11. As a corollary, there should be a study on the rehabilitation of scavengers (Annex 2), whose
servic,es are uti I ised in some countries for cleaning the bucket latrines, to assess the unemployment or
economic deprivation by converting the dry (bucket) latrines into pour-flush ones. The Indian experiFnce
however indicates that latrine conversion programme has neither created unemployment nor under
employment among the scavengers.
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REVIEW OF EXISTING ORGANISATIONAL MANAGERIAL, FINANCIAL CAPABILITY AND LEGAl AUTHORITIES OF THE LOCAL GOVERNMENT AND SUGGESTED REMEDIAL MEASURES
12. In order to judge the capacity of a local authority to prepare and implement a low-cost pour-flush latrine project, these studies are needed for suggesting the institutional set up that would be
required to carry out such a programme, It would also need reviewing the existing legal provisions in local authorities ac1s, by-laws, and rules and to suggest practical and expeditious remedial measures for overcoming the existing inadequacies. Experiences of the India programme have revealed, that legal sanctions have been a very potent force in the conversion of dry latrines into waterseal ones. The basic
requirement is therefore a poi!CY decision by the Government to remove the existing insanitary dry system and ban open air defecation. In order to provide full support to the programme, legal reinforcement appears to be necessary (See Annex 3).
HOUSE-TO-HOUSE SURVEY
13. House-to-house survey should be carried out, compnsmg of data collection in respect of income, availability of water sources and electricity, type of latrine (flush or dry}, to ascertain the socio
economic condition of the individual households for suggesting the financing pattern of the project (loan and grant to individual households); number of persons residing in the household; feasibility of conversion or construction of a new pour-flush latrine in the house with leaching pits inside or outside premises for determining the realistic cost estimate.
SOCIO-CULTURAL ASPECT
14. The socio-cultural aspect of the problem is as important as the technical aspect in a pro
gramme of this type. A recent World Bank study says "It is easier to change technology than to change behaviour and it is more difficult to determine cultural acceptability than technical feasibility··.
15. Awereness, acceptability, availability, adoption and satisfaction* are the five most important ingredients of a programme which could lead to the changing of the existing practice for a more hygienic method, Therefore, for changing the existing insanitary sanitation system to pour-flush type, people should be motivated and mace aware of it. The technology should be such that it is acceptable and easily available.
PROPOSED TECHNOLOGY, ITS OPTIMISATION AND STUDY OF SUB-SURFACE POLLUTION
16. Quite often the planners and administrators lack access to efficient planning and design tools, resulting in non-optimal solution to the given problem, which makes the solution out of reach of
the poor. The service level and the technology selected, should be such that it is acceptable andi afford
able in the first stage of development and could be up-graded subsequently, utilising the existing systems. In most of the developing countries sanitation systems have been built without assessing the requirement,
affordability and acceptability of the people, resulting in non-utilisation and leading to the failure of
the systems.
17. Some basic questions such as the location of the latrine and leach pits, the size, depth and the structure of the leach pits, proximity of hand-pumps, open wells and street water mains, ar,e factors
*Dr. W. J. Cousins, Senior Urban Adviser, UNICEF-Changing Sanitation practices. Some sociological considerations.
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which call for a more discerning judgement from the technical angle. Certain questions arises. What
should be the depth of leach pits ? Can the pan have a steeper slope and the trap a smaller depth of waterseal ? Is a follow up action possible to assess the extent and degree of sub-surface dispersion ? Is there a co-ordinating technical unit to research and discover least cost solution for different situations?
Answers to all these queries have been taken care of by the UN DP Global Project while formulating the Master Plan and Feasibility Study of 110 towns in India.
18. The technology developed by the UNDP Global Project is simple, cons1strng of a squatting pan and a trap, fixed on the floor of the latrine cubicle and is connected to two small and shallow leaching
pits through a pipe or drain located away from the latrine cubicle (drawing attached). The leaching pits are o1' honey comb brick work or of dry stone work according to soil condition. The pits are used alternately and it takes about three years for each pit to get filled up. Because of the steep slope (25° to 30°) in the bottom of the pan and the shallow waterseal, (20mm), water requirement for flushing the excreta to the leaching pits is minimal, about 2 litres per capita per use (See Annex-4)
19. Based on the past studies and experience gained by various institutions in India, a design
guideline has been presented (Annex-4). The optimum values have been arrived at, considering the
cost effectiveness without disregarding performance.
POLLUTION ASPECTS
20. Studies in India and abroad have revealed that if the leaching pits are located in an unsaturated zone and water table is 3 to 4 metres below ground level, the risk of bacterial pollution is minimal. However, even under unfavourable hydrogeological conditions, the system could be adopted with Home precautions and modifications (Annex-5).
INSTITUTIONAL REQUIREMENTS
21. For a successful low-cost pour-flush latrine programme, it is necessary to set up a suitable
institution for programme planning and implementation, oriented to people's needs. "In absHnce of well
planned national or regional programmes, executed by efficiently run governmental bureaucracies, community participation and appropriate technology will count for little*.
22. Experience in India justifies the above statement. lnspite of the presence of an All India Social Organisation (Harijan Sevak Sangh)** in all the States of India, this organisation could meet the sucCE!SS only in one State. The question arises as to what extent the programme owes its success to the supporting input from the non-official advisory agency. Why was this approach not adopted elsewhere,
bearing in mind that this organisation operates in every State of India ? What are the factors which made the conversion of dry latrines into waterseal ones an object of special attention in this particular State and not elsewhere ? The answer to this is simple-because the State Government itself was motivated and dedicated to the cause, and committed to the programme. The non-official agency provided the catalytic influence with its experience, expertise and voluntary involvement. The local authorities too were motivated and receptive to the programme. Personal dedication and drive by the advisory agencies gave the necessary stimulus. Thus, the programme was successful with mutually and complementary input by different agencies involved.
*Dr. F!ichard Feacham-Rose Institute of Hygiene and Tropical Medicine-London.
**A Social organisation for uplifting and bettering the living conditions of socially and economically backward community.
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23. Based on the experience of the ongoing programme in India, four institutional alternatives
could be suggested :
( i ) Establishment of an autonomous Latrine Board or Corporation,
( ii) Creation of a State Authority by the Government, as a High Power Committee.
( iii) Existing Sanitary Engineering Departments, and
( iv) Establishment of a Social Organisation at the State leveL Their functions and responsibilities appear in Annex-6.
METHODOLOGY FOR CONSTRUCTION OF HOUSEHOLD LATRINES
24. Whatever be the organisational pattern of the agency to be entrusted with the programme, the actual installation of latrines would best be carried out by small and medium contractors in the town, who will be the best motivators of the programme, as they will earn their livelihood from it. The procedure
should be such that all the works which normally a householder is required to do from the time of application to the completion of the latrine, is done by one Agency, at the same time the householder is involved! to the maximum possible extent (siting of the latrine, including the selection of design, and fu!i satisfaction with the finished unit). These functions are summarised in Annex--7.
FINANCIAL ASPECT
25. In view of the heavy investment needed for implementing a large scale low-cost pour-flush
latrine programme, it would be necessary to phase out the programme in such a way that this is within
the financial resources of the government. Highest priority should be given to the conversion of all the
dry latrines into waterseal ones, as it involves both social and health problems. Houses withoU1t latrines could be taken up under the subsequent phases.
COST ESTIMATE
26. Obviously the cost of conversion of a dry latrine into pour-flush one or cost of installation of a new latrine, has to be kept to the absolute minimum, consistant with the structural stability and functional efficiency of the unit. Keeping above factors in view the average per capita cost of conversion has been estimated to be US$ 18 (Rs. 150) while that of construction of a new latrine with superstructure US$ 25 (Rs. 21 0) (at 1981 prices for the Indian conditions).
FINANCING PATTERN
27. Past experiences of the implementation of a pour-flush latrine program ne in India have
revealed, that in poor families sanitation carries a lower priority than water supply, therefore if the programme is aimed to serve the poorest of the poor, a liberal subsidy would have to be provided to them.
At the same time those who can afford to pay for the cost of the unit should pay for the fu!l cost. There
fore, determination of the income level of the beneficiaries is very important for such a programme. There
could be three approaches to determine the affordability of a household latrine:
( a ) Income tax liability,
( b ) Assessed value of the property, and
( c ) Access to the public utilities in the households"
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28. It would be difficult to assess the income level of the beneficiaries in view of the fact that
majority of the population in the small and medium urban towns are non-salaried and so income tax liability and household income can only be estimated by guess work. Property value of the households could be another indicator of household income but again it is difficult to rely on the same, as the houses
are not assessed at proper intervals and they may also be over or under assessed. Therefore, the second
proposal also does not appear to be feasible. Thus the only alternative left to assess the affordability
of households for participating in the programme is the access to the public utilities (water connection,
electricity connection and dry latrines as existing) in the premises. These would be the economic indi
cators of the households. Therefore grant and loan to an individual household could be based on the number of public utilities a particular household enjoys. In general, the various state governments in India
agreed to the following grant and loan components : (i) households having at least two out of the three
utilities (water, electricity, bucket latrines)-1 OOYo loan; {i i) households having one of the three utilities-50~0 loan and 50% grant; and (iii) households with no utilities within the premises-25% loan and 75% grant.
29. The Indian experience has further revealed that even if a household has all the public
utilities, paymet of the entire cost of sanitation unit in one lot cannot be afforded by majority of the people. The evaluation study has revealed that if long term soft loans are made available, there would be wider acceptance of the programme. Repayment of monthly instalment should be within 1 to 1·5Yo
of the monthly income
OPERATION AND MAINTENANCE
30. Day-to-day maintenance of the latrine consists of only washing the latrim! cubicle and
cleaning the squatting pan. This would be the responsibility of the householders. After about
three years, when the first pit gets filled up, the discharge can be directed to the second pit. This is a
simple operation and can be handled by the householders themselves.
31. When the pit contents are left for about two years, they become pathogen froe, and can be
marketed easily. The NPK values of the pit contents are 1.5, 1 and 1% respectively. It has been estimated
that its rerroval and market cost will break even. However in the initial stages, emptying of household pits, including its marketing, should not be left to the individuals but should be municipalised and local auf1orities in collaboration with local agricultural extension workers and farmers' associations should develop a market for the collected humus.
MAI\IUFACTURE OF PANS AND TRAPS
32. In a number of developing countries the problem of manufacturing ceramic squatting pans
and su:table traps may also arise, in view of the limited IT'anufacturing capacity of the existing units or
because of the heavy capital investment requ:red to establish a new factory. To solve this problem, TAG* has provided assistance to the manufactures in India in developing light weight GRP** pans and traps
wh:ch cost less than the ceramic ones and can be manufactured conveniently as a small scale industry.
TAG is also providing advice for manufacturing pans and traps of PVC and HOPE in India.
*TAG-Technology Advisory Group, UNDP Global Project GL0/78/006.
**GAP-Fibre glass reinforced polyester plastic.
EVALUATION OF ONGOING LATRINE PROGRAMME (HOUSEHOLD
IN URBAN AREAS
TERMS OF REFERENCE
A. HOUSEHOLD LATRINES
ANNEX-1
AND PUBLIC)
{a) The study at the state level should be done specifically to examine and evaluate:
means adopted by the Government to orient its administration favourably towards the programme and to mobilise local authorities to actively co-operate with it and equip with needed skills to implement it;
the Government efforts to promote the programme; and
whether any financial incentives by way af subsidy andfor loan were provided to local authorities and individual households for installation of waterseal latrines and whether loan is being repaid by the adopters and if not, what are the reasons.
(b) The objective of the study at local authority level should be to exa:1mine and
evaluate:
whether the existing Municipal Acts, Rules and By-Laws are conducive to thH implementation of the programme; if not necessary amendments are needed;
institutional arrangements availabe to implement the programme; its adequaciesfiinadequacies and remedial measures to be taken ;
whether any incentives including financial and technical assistance were provided by local authorities including the procedure and the results obtained;
the efforts to disseminate knowledge about the programme to the people, to educate and motivate them to co-operate and adopt the programme ; and
the impact of the above on the people.
{c) The study at- household level should be undertaken :
to know the experience and reaction of adopters about their satisfaction with rElgard to the
technology, implementing agency responsible for construction, health education, motivation and maintenance of the units already installed ;
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to assess the attitude of the non-adopters towards the programme;
to assess the willingness of the non-adopters to take loan for conversion of existing dry latrines into waterseal pour-flush type and also for construction of new such latrines; and
to assess the socio-economic profile of the adopters and the non-adopters.
B. PUBLIC LATRINES
The study should be intended to assess :
the availability of commun ity latrines, stage of their development and their present
situation;
socio-economic profile of the beneficiaries ;
the extent to which they are being used by permanent settlers and the casual visitors;
acceptability, inhibitions and constraints; and
management (including financial, administrative and technical aspects).
ANNEX-2
REHABILITATION OF SCAVENGERS
(TERMS OF REFERENCE)
The study should comprise of :
the assessment of unemployment problems faced by scavengers, as a result of implementation of low cost waterseallatrine project;
impact of conversion programme on life style, as well as on vocational and economic aspirations of scavengers;
analysis of scavengers' aspirations regarding occupational future of their children; and
finally measures to be taken for their economic rehabilitation.
ANNEX-3
SUGGESTED PROVISIONS IN MUNICIPAL LAWS
1. Building by-laws should make the conversion of dry latrines into water-flush ones obligatory within a specified period.
2. The Municipal law should include provisions enabling the local authority to carry c>ut the conversion/construction of a new latrine where none exists at the cost of owner. if he faHs to do so.
3 The existing by-laws should provide a clause that all houses proposed for construction or reconstruction should invariably be provided with a water-flush latrine.
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ANNEX--4
TECHNOLOGY OPTIMISATION
1. The pit size in case of a 5 user latrine is one m3tre diameter an::l about a metre deep (effective depth). Each pit lasts for about three years, before it gets filled up. The pit is then pv.1t out of use and excreta is diverted to the second pit. When the first pit is left without use for about two years
or so, the pit contents become a rich humus, free of pathogens and can be used as a manure. The first pit is then ready to be put into use when the second pit becomes full in its turn.
2. Leaching pits can be located inside a house, under footpath or main road. An oval pit wi'th parti~ion wall or pits of smaller diameter, but deeper depth, could be constructed (provided the water table is low), if there is space constraint. In case of narrow lanes, latrines of a few houses can ba joined to a
sewer leading to leach pits located at some distance. Studies in India revealed that there is no choking in
the connecting pipes even when the distance between leaching pits and latrine is betWe!en 15 to 20 metres. in such cases the connecting pipe has, however, to be laid at a steeper slope (1 in !) to 1 0).
3. Design guidelines and optimcJm values
Item 9J>!imum Other options
( i ) LATRIN"E CUBICLE 750 mm x 900 mm 900 mm x 900 mm or 800 mm x 1,000 mm
{ i i ) SQUATTING PAN
(a) Top opening 125 mm 125 mm
(b) Width of back portion of pan 200 mm 200 to 225 mm
(c) Vertical drop in front wall 75 mm 50 to ?f) mm
(d) Horizontal length 425 mm 425 to 460 mm
(e) Slope of base of pan to horizontal 25c 25° to :wu
( iii ) WATERSEAL TRAP
(a) Depth of waterseal 20 mm 20 rnm
(b) Diameter of inlet 75 mm 75 mm
(c) Diameter of outlet 70 mm 70 mm
( iv ) CONNECTING PIPE OR CHANNEL
(a) Size of pipe 75 mm 75 to 1 OOmm
(b) Size of channel 115 mm x 75 mm 115 mrn x 75 mm
(c) Slope 1 in 10 1 in 5 to 1 in 15
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Item
( v ) INSPECTION OR JUNCTION CHAMBER
Size
(vi) LEACHING PIT
(a) Shape
(b) Effective capacity for sludge accumulation under :
( i ) Dry condition*
( ii ) Wet condition**
(c) Design period
(d) Minimum spacing of pits
*Unsaturated zone.
**Saturated zone.
Optimum Othe1r options
250 mm x 250 mm 250 mm x 250 mm
Circular Circular, oval, rect-angular and square
0.05 m3 /capfyear 0.045-0.0!5m8 ;cap 1year
0.066 m3 /cap/year 0.055-0.06!)m3jcap 'year
3 years 3 to 5 yE:ars
1 x effective depth 2 x effective depth@
@May be relaxed with proper precautions by providing an impervious barrier like cut-off screen or puddle wall.
-14-
ANNEX-5
POLLUTION ASPECT*
1. Studies carried out in India, USA and elsewhere have shown that alluvial soil (with predominance of silt mixed with clay and fine sand) where pits are located in an unsaturated zone, ttle risk of
bacterial pollution is minimal, provided the bottom of pit is at least 2 metres above the maximum water table and the hydraulic loading in the pits does not exceed 50 mm per day (equivalent to a discharge of 40 litres per day in one metre diameter pit). Where the pit extends in saturated zone, pollution travel depends mainly on the velocity of the ground water. With the continued usage of the pit, clogging of the soil around the pit takes place, resulting in the regression of pollution plume which ultimately stabilises
within about one metre distance**.
2. Even under unfavouable hydrogeological conditions such as coarse soil, high ground water velocity and high water table, the leaching pit system can be used providad certain modifications and precautions are taken, such as providing an envelope of fine sand of average size not more than
0.2 mm and a minimum thickness of 500mm all round the pit and the bottom sealed off by any impervious
material, such as polythene sheet or puddle clay. If fine sand is not available, whatever coarse material is available may be screened through a sieve of 0.6 mm and the material passing through it can be used. This should also be adopted where bottom of the leaching pit is within 2 m of the water table. In high water table conditions, the inlet to the pit should be kept at least one metre above the maximum water table. This condition may necessitate raising of the latrine floor.
3. In conditions such as rocks with fissures, chalk formations, old root channels, pullution can flow long distances. These conditions demand careful investigation and necessary modification of the
system or adoption of alternative technology.
4. !n case the pits are located under the roads or streets, the invert level of the connecting pipe to the leaching pits should at least be one metre below ground level, so that the liquid level in the pit does not rise above the water-supply mains, which are generally laid at a depth from 0.8 to 0.9 metra below
ground level.
5. It is desirable to monitor periodically the quality of ground water in the area where the programme is implemented. The monitoring programme should cover periodical sampling of ground water and
analysis for at least faecal coliform and nitrate.
*The conclusion drawn is based on a limited study done in India. Further work on the subject Is under progress by the Inter
national Working Group on Water and Soil Pollution from leaching pits.
**Expert Group on Design Criteria on pourflush waterseal latrines-TAG (India).
-15-
ANNEX-6
FUNCTIONS AND RESPONSIBILITIES OF ORGANISATIONS
The organisation at the State level should be responsible for :
policy making, mobilising the necessary resources, guiding local authorities in the imple
mentation of the programme :
setting up of a nucleous of technical and administrative staff to serve as the executive arm of the authority to help in programme planning, fund allocation, co-ordination of field acti
vities and to monitor the field work, provide programme intelligence and report to tt1e
authority, establish training to social workers, supervisors, junior engineers, sanitary inspectors,
organise concurrent research on sociological, economic and technical problems emergi111g
during programme implementation and to make alternative arrangements, where any imp~:l
menting agency fails to undertake the programme satisfactorily.
ORGANISATION AT LOCAL LEVEL
By and large local authorities in all the urban centres are primirily responsible for providing water
supply and sanitation facilities to their citizens. They have adequate powers to give loans and grants to the beneficiaries and have remedial powers in case of default. Therefore, local authorities in the urban centres
should be charged with the responsibility of implementing the programme and made responsible for:
preparing the detailed programme of worl<, identifying the target locations;
receiving and disbursing loan and grant funds from the Government;
organising training of staff and local contractors;
implementing the programme;
arranging for emptying of household leaching pits; and
recovering the loans from the beneficiaries.
-16-
ANNEX-7
PROCEDURE FOR CONSTRUCTION OF HOUSEHOLD LATRINES
1. A householder wishing to have a waterseal latrine should enter into an agreement with the local authority to ensure timely repayment of loan. The funds available for the construction should be paid to the contractor by the local authority on the completion of the work.
2. The licensed contractor would visit the house of such interested persons to assess the space available for construction of the latrine and leaching pits, the number of users. and decide with the householder, the design which is suitable. At the same time public water supply and electricity connections should be checked, as they would be used as economic indicators to determine the quantum of subsidy to be provided.
3. These details should be set down by the contractor on a standard form, which the houseowner would endorse by signing an agreement The houseowner would also be provided with a list of materials and latrine dimensions.
4. The contractor would take the endorsed form, together with a sketch plan of the proposed installation to the local authority for approval. The junior engineer or sanitary inspector will then visit the site and check the type and location of water supply source, structural condition of the house etc.
5. The completed installation would be inspected by the junior engineer/sanitary inspector, who would furnish completion certificate fully endorsed by the houseowner. The contractor would be paid the standard cost of the latrine on production of the above certificate.
PLAN
25MM TH.CEMENT CONCRETE J:2:4 OVER 15MM TH. C. C. 1:6:12 f
I
i I I I t ~
I ~
~-~- .. ~- ~ 0[SIGI~ 0~ U:lW-C05i WA'ff.R -SEAL LATRINE
FOIR PIT& \?J!fHIN Hl[ P~EMISE S
· AlL OiMH~SiONS !N M.fJI SCALE·-~ l: 300 .
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