29 September - 2 October 1984

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HEALTH ASPECTS ON WASTEWATER REUSE

REPORT ON AN INTER - COUNTRY SEMINAR

MANAMA, BAHRAIN

29 September - 2 October 1984

WORLD IIEALTII ORGANIZATION EASTERN' MEDITERRANEAN REGION

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WHO-EM/ES/351 January 1985

HEALTH ASPECTS OF WASTEWATER REUSE

REPOR1' ON AN INTER-COUNTRY SEMINAR, MANAMA, BAHRAIN 29 September - 2 October 1984

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Report of an Inter-country Seminar, Manama, Bahrain 29 September - 2 October 1984

EM/INC.SEM.Wlm/17 page i

Abstract The first Inter-country Seminar on Reuse of Treated Wastewater in WHO's Eastern Mediterranean Region was held in Bahrain from 29 September to

2 October 1984. Attending the Seminar were representatives from Bahrain, Egypt, Jordan, Kuwait, Morocco, Oman, Saudi Arabia, Sudan and Tunisia, as well as international experts. The objectives of the Seminar were to review and .exchange inf<>n!lation and experience on treated wastewater reuse practices in <:ountries of the Eastern Mediterranean Region. Emphasis was placed on the

health effects of different types of reuse. Country representatives reported on the eurrent situation in their countries, and frank and constructive discus sions on the problems and possible solutions were held. The participants were later divided into three working groups which addressed Health, Engineering and Economic Aspects of wastewater reuse in the Region. A eommon regional problem

is the scar�ity of water resources and it was felt that controlled reuse of created wastewater in agriculture could play a significant role in redueing t� abstraction of gcoundwaters and, at the same time, in decreasing the pollution of water �ou�ces now used for drinking water supply. More than one thousand million �ubic metres of reclaimed sewage is being used in the United States of America every year, and it was felt that the Region should draw upon its

experience and take advantage of this important resource. Under no conditions was reuse of �aw sewage.considered acceptable in the Region. A strong national tommitJitent to treated effluent reuse was deemed essential if the control neces �ary to protect public health is to be achieved. Coupled with this, health education and public information programnes vere considered to be important elements of wastewater reuse projects. A range of technology is already available to upgrade sewage to any level of quality, but prescribed effluent standa�ds have to be achieved consistently in reclamation plants. This can be attaim!d through careful monitoring of treatment processes by well trained personnel. Regular epidemiological surveillance was judged to be an essential component of any controlled reuse project. Several eountries in the Region, notably Bahrain, Kuwait, Saudi Arabia and Tunisia, are already making progress with treat.ed effluent reuse, and the participants believed that it is timely <o �stablish �tandards to be associated with different types of reuse. Research

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WHCr-EH/ES/3S1 EM/INC. SEll. WWR/ 17 page v

IN THE NAME OF GOD, THE COMPASSIONATE, THE MERCIFUL MESSAGE FROM

DR HUSSEIN A. GEZAIRY

REGIONAL DIRECTOR, WHO EASTERN ?IEDITERRANEAN REGION

to the

INTER-COUNTRY SEMINAR ON WASTEWATER REUSE Manama, Bahrain, 29 �eptember - 2 October 1984 Excellencies, Ladies and Gentlemen,

lt gives me great pleasure to send you a message of welcome on the occasion of this Inter-country Seminar on Wastewater Reuse, first of its kind that WHO has organi�d on this subject in the Region. Let me take the first opportunity also to convey to the Government of Bahrain our sineere thanks for hosting this important Meeting.

Few countries in �he world have a greater need for a lasting supply of safe water than the majority of our Member States. In many, what little fresh water is available is used as potable water, and there is none for agriculture.

Considering the low cainfall, the often saline groundwater and the lack of river and surface water, treated wastewater offers a valuable resource for irrigation and other purposes. Controlled reuse is,however, essential. With proper planning and technology, wastewater can be upgraded for a number of purposes; irrigation is one of the oldest fotms of water use and Yeuse, while industrial recycling of water is on the increase.

tn many of the countries of the Region, it is a common practice to use untreated sewage for irrigation, and for the watering of parks and gardens. This brings with it '['eal health haiards if proper precautions are not t:aken

to kill bacteria, viruses and helminths contained in the sewage, and which

othervise contribute �ubstantially to spread of disease. Appropriate technology in this area already exists and is well-known. Experience gained with such practices; both within the Region and world-wide, are encouraging. However, proper implementation, management and continuing surveillance are prerequisites for safe t"euse.

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E�'/l�C. SDf. t,J'lm./17 n<'l�e vi

WHO has been actively collaborating with many countries of the Region in identifying the various health hazards associated with the reuse of untreated wastewater. Countries are becoming aware of_ the problems and are trying to improve their reuse practices, and some have made considerable progress in this respect during recent years. However, much remains to be done before a

satisfactory proportion of wastewater can be reused to maximum advantage and with no side effects. To this end, WHO has provided technical support to Jordan, Kuwait, Saudi Arabia, Tunisia and the United Arab Emirates.

In the above context, this Inter-country Seminar provides a forum at which participants will be able to concentrate on the health aspects of wastewater

reuse pertaining to the specific situation of countries of the Eastern Mediterranean Region. Your presentations and discussions will add to the body of knowledge

and to a better understanding of needs and priorities, and I fell that your conclusions and recomnendations will be an important contribution to further progress in this field. The meeting is, however, only a beginning and I urge the national participants, when they return to their respective countries,

to transmit their knowledge onward, for example by organizing national seminars on this subject. WHO would be glad to support such action, which is an essential prerequisite for �enerating the corps of trained nationals required for proper management of a comprehensive programme of wastewater reuse.

In conclusion, let me again express my thanks to the Government of Bahrain, in particular to the Ministry of Health, for having made it possible for us to hold this Seminar here in Manama, and that too, at a short notice, and for all the help and facilities which have been and are being extended to make it a fruitful one, I wish also to extend my appreciation to the Chairman of the National Preparatory Comnittee and his staff as well as to all the experts and

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WHO-EM/ES/351 EM/INC.SEM.WWR/17 page vii

TABLE OF CONTENTS

Abstract

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Preface (English) MESSAGE FROM DR HUSSEIN A. GEZAIRY REGIONAL DIRECTOR, 1. 2. 3. 4. 5. 6. 7. 8.

WHO EASTERN MEDITERRA..�EAN REGION

INTRODUCTICN

. . .

.

. . .

OJNCLUSIONS AND RECOMMENDATIONS

...

ACKNOWLEDGEMENT

... -... .

LIST OF PARTIC.IPANTS

... . ... ... ...

ANNEX I AGD-lDA •••••••••••••••••••••••••••••••••••••••••••••••

ANNEX I I PROGRAMME

... ...

ANNeX III LIST OF BACKGROUND DOCUMENTS

...

ANNEX IV �ORKING GROUP MEMBERS

... ...

ANNEX V SUGGESTED TOPICS FOR GROUP DISCUSSION

... ..

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EM/INC.SEM.WWR/17 page 1

Report of an Inter-country Seminar, Manama, Bahrain 29 September - 2 October 1984

1. INTRODUCTION

Wastewater reuse has been practised in an uncontrolled fonn for many years in several countries of the Eastern Mediterranean Region and concern has been �xpressed about i ts adverse effects on health. Reuse of wastewater can make a

positive contribution to solving the problem of water shortage. which is a common feature in the Region, and-can also provide benefits in the form of furthering food production. Controlled reuse in irrigation is one of the principal applica tions for treated wastewater and, with proper controls, public health risk can

be eliminat-ed. However, little is known about the types of wastewater treatment

technolop.y that would be appropriate in countries of the Region for upgrading sewage to a suitable quality for a particular reuse application or about the

quality standards which should be associated with a particular use in irrigation.

Epi-demiological studies of reuse projects have not been conducted in the Region, wile the health risks involved in different forms of reuse are not w�ll under

Nevertheless, �ome countries are pressing ahead with wastewater reuse programmes.

'Consequently, WHO EMRO felt it to be timely to convene this first inter -country meeting on the topic, to consider the state-of-the-art in wastewater 1:"euse and address the problems faced by different countries in the Region. 2. OBJECTIVES OF THE MEETING

The objectives of the meeting were:

{a) to review and exchange information and experience on treated wastewater reuse pr�ctices in countries of the Eastern Mediterranean Region;

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3. PARTICIPATION

The meeting was attended by 13 participants, representing 8 Member States, and one participant each from WHO Regional Office for Europe and UNEP. They. were supported by one WHO staff member each from the Headquarters and EMRO, and three WHO consultants. The observers from the host country were able to play an active part in both plenary and working group sessions. A list of participants, WHO Secretariat and observers concludes the report.

4. THE MEETING

Presented in plenary sessions, the basic papers covered various aspects of wastewater reuse, national policy formulation, programme implementation, opera tional and managerial processes, health aspects, engineering, and pollution monitoring and analysis.

Subsequently, country presentations referred to national activities and experiences in the field of wastewater reuse, while delegates from UNEP and WHO Headquarters presented accounts relating to the respective areas.

Three working groups were then formed to identify and discuss the specific problems and issues facing wastewater reuse and formulate guidelines for future activities in the Eastern Mediterranean Region.

Based on the summary reports of these working groups, the guidelines were reviewed and finalized in plenary sessions, and the meeting concluded with a formulation of conclusions and recommendations for future action.

5. PLENARY SESSIONS

5.1. Opening of the meeting

The meeting, held at Diplomat Hotel, was opened by Mr Mohammed Rahma Al Tajir. Assistant Under-Secretary for Administration and Planning Affairs. on behalf of

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5.2. The message of the Regional Director EMRO, Dr Hussein A. Gezairy, was delivered by Mr T. Zeribi, Regional Adviser on Enviroranental Hazards and Pollution-Control, E�O.

5.3. Election of Officers. Mr Ali Jaffar Anjawi (Bahrain) was elected as 'Chairman and M�ssrs Emran M: Amin Katib (Saudi Arabia) and Yusri Ali Hassan {Sudan) vere elected as Rapporteurs.

5.4. Adoption of the Agenda. The agenda and programne vere adopted as given in Annexes I and II. A list of documents is to be found in Annex III.

HEALTH ASPECTS

S.S. Health Aspects of Reuse of Treated Wastewater for Irrigation was presented by Mr T. Zeribi. He surmnarized the routes by which pathogens can be potentially transmitted to humans practising wastewater reuse. The major hazards identified �re: risk to agricultural workers by direct contact, accidental ingestion of contamined wasuvater, incn!a�d breeding of vectors of disease (e.g. mosquitoes, flies) and crop and groundwater contamination. Questions vere raised about the inability of the Health Department to enforce standards. It was pointed out that effective legislation was necessary for setting and implementing enforcement standards and for licensing and monitoring of reuse practices. 5.6. Evaluation of Health Hazards of Wastewater. Mr Cunnar Schultzberg, UHO l:leadquarters, Ceneva, presented this paper. He discussed various types of evaluations for assessing the health effects and various factors which might influence the rate and extent of infection in a community folloving wastewater reuse.

Questions were £aised about the validity of a sta�ement made by

Dr Y.J. Schaefer in his background paper <EM/INC.�EH.WR/4) which stated that " ••• where an infection i.s highly endemic in a poor community, the introduction of a pat"ticular pathogen ••• may have a negligible impact on transmission".

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WHO-EM/ES/35 1 Eli/INC . SEM . WWR/ 1 7 page 4

5 . 7 . Environmental aspects of wastewater reuse . Mr Laszlo David thanked WHO for the invi tat ion extended to UNEP to part icipate in the Seminar. Water is one of the main e lements in the environment ; its reuse not only results in a decrease in freshwater withdrawal but also reduces the discharge of sewage effluent . The inter-relation between human health and reuse , particularly for agr iculture , is the mos t important environmental factor . A recently approved project , to by executed by WHO , with epidemiological case studies, aims at provid ing guidel ines for minimizing health hazards in the reuse of was tewater .

On a quest ion regard ing coord ination between UNEP and WHO , Mr Salih Osman ,

Regional Di rector , UNEP , expla ined the catalyti c rol e played by UNEP to encourage nat ional governmen ts , UN special ized agenc ies and bi laterals to

fully consider environmental aspects t hrough the inj ection of fund s for speci f ic proj ects .

5 . 8 . Enteric disease transmiss ion associated wi th was tewater utilizat ion in agricultural communitie s . Dr Sagar M . Goyal , WHO Consultant, made a n expose of potential hazards connected with alternative reuses of wastewater. Although there is one successful case of potab le direct reuse of wastewater through

blend ing of up to one-third of treated wastewater with f resh water , non-potab le use rema ins the h ighes t potent ial for reuse. Almos t complete removal of

pathogen ic bacteria can be achieved through waste s tab i l izat ion ponds . There is , however , re latively l i ttle known about viruses , some of which can survive longer t han faecal indicator bacteria. Viral infect ion of crops irrigated with wastewater may possibly lead to infection in humans . More research is needed

in the Region on health hazards from wastewater reus e . Set standards should be kept under review as new knowledge becomes available through research .

5 . 9 . Reuse of was tewater for irrigat ion of food crops - heal th and safety cons iderat ion s . Dr r.oyal stated that reuse of wastewater for crop irrigat ion

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EM/INC.SEM.WR/17 page 5

irrigat ion tecbnique, level of sewage treatment, survival of pathogens in soil and crops, and the disease susceptibility of crop consumers.

Survival of bacterial and viruses on soils and crops varies widely, and is dependent upon soil moisture, soil pH, organic matter, antagonistic microflora,

rainfall, temperature, sunlight, hmnidity, moisture-holding capacity of soil, storage conditions of crops after harvest, and the numbers of pathogens initially applied. In general, pathogenic bacteria are �educed to negligible levels

in 2-3 months, but survival times of as long as 5 years have also been reported. In soil, viruses can survive for 1-26 weeks, whereas in crops, they survive for a shorter period.

�uggested guidelines for controlling the spread of infection by erop contamination are:

{a) raw sewage should not be used for crop irrigation;

<h) ra�aten �rops should not be irrigated with conventionally treated sewage ; (c) animals should not be allowed to graze for 2-4 weeks efter waste application

to pastures.

5. 10. Health effects of wastewater reuse by �roundwater recharge.

Dr -Goyal 111entioned that almost one-half of all the water-borne disease outbreaks reporc-ed in the United States are caused by contaminated groundwater. An under standing of the factors that control the survival and migration of pathogens through the subsurfaee soil systems is, therefMe, critical in the management of groundwater TI?charge operations by rapid infiltration and deep well injection.

Vit:'Us removal by soil is believed to be la�gely caused by adsorption, whereas bacterial removal occurs by a combination of sedimentation, filtration, and

adsorption wicll, in turn, are �ontrolled by such factors as composition of soil, ionic strength, pH, type of pathogens, flow rate, etc. The survival of pathogens depends upon climate, nature of soil, and nature of the micro-organisms.

Temperature and climate are two important factors in detennining bacterial and viral �utvival.

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and pr ior evaluat ion of the si te with regard to the nature of soi l and depth to groundwater.

ENGINEERING ASPECTS

5 . 11 . Evaluation of agricultural proj ects us ing reclaimed municipal wastewater Mr Fordham' s presentation consisted of a review of two separate studies where exis ting agricultural reuse appl icat ions had been examined to evaluate :

(a) sui tab i l ity of wastewater effluent s for crop product ion ; (b) the benefits derived from such an activity ; and

(c) l imitat ions imposed on us ing was tewater for crop production .

These studie s determined that the key e lement s of water qual ity aspects were re lated to soi ls . crops , human health. economics , and public accep tance . The reviews of thirty divers e wastewater reuse proj ects showed that techn ical capab i l it i es were wel l deve loped and that agronomic-enginee ring re lationships were at hand to implement readily sound irrigat ion application of was tewater , but that site-spe cific public concerns still exis t . Recommendations were put forth that there needs to be continued research on pathogens and heavy metal problems related to i rr igat ion uses and that pub l ic education i s nece ssary for successfu l implementation of reuse .

5. 12. Environment al operat ional guidel ines for irrigation i n arid and semi-arid regions . Mr Fordham ' s presentat ion emphas ized that in planning wastewater irrigat ion applications three primary s teps mus t be taken to protect the

environment and to ensure the viability of the project . First , the potent ial hazards mus t be identified in all parts of the conveyance , storage and distribu t ion syste� for wastewater itself , re lated to health and related to compatibility of the wast ewate r with soi l and groundwater cond i tions . Once the potential

adverse env ironmental effects have been ident i fied , the second s tep is to es tabl i sh mechanisms which will de tect these , i . e . a thorough moni toring network for each

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5. 13. Appropriate wastewater reuse technology.

EM/INC. SEM.'WWR/17 page 7

Professor Pescod stated that technology adopted in wastewater reuse projects must be designed and operated

to convert raw wastewater into an effluent suitable for a particular use. The technology must be appropriate to each particular nation, considering local eonditions and other resources, including monetary and manpower training requirements. The technology level should be chosen considering the end use cf the �ffluent, since requirements will vary between industrial, irrigation

and groundwater recharge �euses. It was pointed out �hat irrigation standards are n ot uniform and must be matched with soil properties and the proposed manage ,nent techn ique. It was also noted that the more stringent the standard being met, the higher the cost of treatment and that the quality of trained manpower will be at a very high level. Suggestions were made that it was most appropriate to start at the lowes t treatment level and use ae<:eptable standards based on public health considerations and then move to higher uses as experience and �apabilities increase. Treatment process reliability was pointed out as a

significant concern together with monitoring requirements of various un_it processes in hot climates. A brief reviev of the general capabilities of varying levels of treatment was made, indicating the suitability for producing reusable effluents. Note was made of the fact that �urrent treatment practices were designed to produce eff luents primarily for stream disposal and that other more simple processes such as stabilization ponds may actually produce effluents more suitable for reuse from a health standpoint. Questions centred around experiences with existing reuse projects and the levels of treatment which have proved satisfactory.

discussed. Various field application methods for irrigation were 5. 14. Site selection techniques for land disposal of treated municipal wastewater

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WHO-EM/ES/351 EM/INC. SEM.WWR/17 page 8

water and application rate. The basic easily obtainable information needed was enumerated for preliminary selection, which would then be folloved up by site inspection and collection of additional site specific data. Once data on soils, climate, groundwater, and topography, etc. have been collected, it will be possible to assess the potential impact of wastewater application at the s ite. This assessment of environmental im9acts together with estimates of land and conveyance costs for the site will dictate the best site.

ECONOMIC ASPECTS

5. 15. Economics of wastewater reuse. Professor Pescod mentioned that there can be no question of reuse of wastewater without its collection, which is the biggest cost. Some recovery of downstream costs in terms of treatment,

conveyance, storage and distribution can at least partially be offset through charges for reuse of wastewater and treated sludge. The more sophisticated the treatment method is the higher are the costs for operation and maintenance, in addition to higher requirements for skills and knowledge among operating staff. As long as cost of land is within reasonable limits (US$45 000 per acre, 1980 prices) advanced waste treatment processes are not competitive with waste stabilization ponds. The cost of aquifer recharge by d�ep well injection is twice the cost of surface infiltration. The optimum economic choice of irriga tion equipment is very sensitive to the cost of labour.

5. 16. Development of a methodology for evaluating integrated water reuse/waste-water treatment alternatives. Mr Fordham' s presentation addressed the problem of integrating wastewater reuse within the total water supply/wa�tewater ma�age-

_O

ment structure, thus ensuring that reuse elements were compatible with the entire

water resou%ce system. A methodology was presented which considers a multi-step process , moving from initial simple resource allocation to a complex allocation model of the real system being evaluated • . The approach allows screening of non-viable reuse alternatives in the early planning stages, and ensures that the reuse options chosen will remain effective considering hydro logic variations and water demand variations in the future. Discussions centred on the ability of this approach to address situations where supply options are limited and where components are inter-related • . , It was stressed that the methodology is applicable to both large complex �roblems where many different

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EM/INC. SEM.Wt-.'R/17 page 9

-0ne potable 5upply is available. The methodology will result in identifying the best �ombination of supply/wastewate r treatment and reuse in either case. MANAGERIAL APPROACH

5. 17. National plan of action for reuse of treated wastewater for irrigation Mr Zeribi emphasiied the need for formulation of national plans of action by various �vernments concerned, before they undertook any ambitious programmes on wastewater �euse. High level commitment on the part of the agencies con

cerned and effective legislation to implement a formulated programme were recogni�ed as two important elements in the success of a reuse programme. 5. 18. Development of wastewater reuse prograrmnes. Mr John W. Fordham, WHO <onsultant, mentioned that wastewater is commonly reused for irrigation in an

unacknowledged and unplanned way. Only recently has the potential for reuse been integrated vith the overall demand and supply manag�ment of water. The main �lements of a wastewater reuse programme include: definition of goals, evaluation of needs and potentials, inventory of complementary resources,

review of political, legal (in particular health legislation) and institutional barriers , and establishment of suitable management structures. The crucial

importance of public involvement and acceptance was stressed. Early coordination between all parties concerned was considered essential to avoid later conflicts auring the implementation phase.

5. 19. Uastewater reuse and its implications. Professor M.B. Pescod. WHO Consultant, mentioned that the countries of the Region are not homogeneous vith <""egaf<! to socio-economic development and potential: this means that it vould not be practical to aim for uniform national standards. Cultural and <"eligious taboos are very important, and potable reuse of vastewater would hardly be acceptable. The indirect route through the recharge of aquifers and

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itself fonns part of the t reatment , is essential. To maintain a safe supply of wastewater means that 100% reliability is necessary: resource requirements for

operation and maintenance phase are crucial. COUNTRY PRESENTATIONS

5. 20. Country presentation , Bahrain (Mr Ali Anjawi). To preserve the water resources of the State of Bahrain, Tubli Water Pollution Control Centre was constructed with the objective of resource recycling. The treatment train consists of extended aeration activat ed sludge process, mixed media filtration , and disinfection. Currently, the tertiary effluent is discharged into the sea, pending the implementation of reuse schemes. Bahrain ' s Water Supply Programme was presented by Mr A. Rasul Mussayab, Chief Engineer, Water Supply Directorate He stressed the Government ' s aim to gradually reduce annual abstraction of

water from the ground and t o maintain the present massive desalination programme. Dr T.I . Emecz, Directorate of Agriculture, summarized Bahrain's Plan for the Reuse of Treated Wastewater. Two regions consisting of 14 zones for a total of 763 ha will be irrigated with properly treated wastewater. During discussion , Bahrain was commended for taking the lead in recognizing the problem of water shorage and taking steps to rectify it .

5. 21. Count ry Presentation, Egypt (Dr Maher H. Danial) : Old standards (1946 - 54) for effluent discharge have been replaced by newer and more comprehensive

standards of 1962 and 1982. Under these standards, discharge of industrial effluent through watercourses is prohibited if it contains pesticides, radio active substances, floating particles, or any other material hazardous to man,

plants,anim�ls, birds, and fish. In addition, discharge of treated domestic sewage in surface or groundwater aquifers is absolutely prohibited.

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EM/INC .SEM.WWR/ 1 7 page 1 1

appl ied t o indus trial discharges and these have encouraged wastewater reuse in industry and protected underground water sources .

Considerat ion is now be ing given to agricultural reuse of effluents after tertiary treatment for unrestricted use or after secondary treatment plus

chlorinat ion for restricted use in irrigation . Monitoring of reused wastewater wi ll include bacteriologica l , chemical and biological ana lyses . The activities of the various agenc ie s will be coordinated through committees formed for the purpose and these will include representat ion from ind ividual farmers ,organized by the Minis try of Agriculture .

5 . 23 . Country presenta tion , Kuwait (Dr Shaaban El-Hadary) : Kuwait re lies primari ly on desal inat ion of seawater for its potable supply; therefore wastewater reuse for irriP-at ion is extremely attract ive . Reus e has been taking p lace in Kuwait for a consi&erable pe riod of t ime in one form or another . Originally , before 1959 , septic tank effluent was collected and d ischarged to a green belt area. After tttatment began in 1956 effluent was used on an experimental farm to

irrigated alfalfa. With t he establishment of a sewerage col lection network in 19o9 the effluent was pumped to the Ardiyah activated s ludee treatment plant and �as used as a 9 x 106 m2 area in the Sulaibiah district for agricultural purposes . T.his wastewater i�rigat ion project is now priva te ly operated , growing a lfalfa , vegetables , and trees . S ludge from the treatment plant is also used at the s ite as a soil condit ioner. Plans are currently laid for using treated eff luent from three other treatment plants eventually reusing 380 000 m3_{/d of}

eff luent . Limited monitoring of the exis t ing appl i ca tion s ite has not ident i f ied any serious problems .

5 . 24 . Country presentat ion, Morocco (Mr Fouad Marrakchi ) : Morocco be ing a country w ith fflOre than 22 000 000 people and a c l imate varying from Mediterranean on the coast to arid in the south presents several potential opportuni ties for wastewater

reuse . The urban populat ion, 45% of the total , derives its supply from both surface and r,roundwater source s wi th desal inat ion of brackish water bein� necessary

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emphasized that the lack of proper collect ion and treatment poses a significant health problem . For correct ion of this problem and to mitigate the lack of p recipitation over the last few years , the Government has begun to consider vastewater reus e to augment exist ing water suppl ies and to help eliminate environmental pollution . A commission has been set up to study reuse . Also a pilot proj ect util izing effluent for recharge has b een constructed a t Marrakech with the aid of UNDP . The results of this project will be disseminated to

s imilar areas throughout the country to accelerate the implementat ion of reuse in several areas .

5 . 25 . Country presentation , Oman (Mr Al i Bin Mohammed Al-Rashdy) : Oman prohib its the discharge o f was tewater into the marine environment . In addition to several septi c tank systems in villages , there are 126 small sewage treatment systems . The e ff luent f rom these i s inj ected into sal ine aquifers . The wastewater quality standards appear to be fairly strict and the incidence of malaria was c ited to be down because of this .

5 . 26 . Country p resentation , Saudi Arabia (Mr Emran A. Katib) : Treated eff luent from Riyad is used f or irrigation of an area 30 km away from the city . In several othe r c ities the effluent from the sewage treatment plants i s used for irrigat ion within the fenced-off area of the plants . At a nat ional confe rence on reuse of wastewater in 1980 , i t was agreed that nat ional standards for sewage treatment should be establ ished . A common framework for national standards wi thin the Gulf States would fac i l itate the establishment of standards and necessary moni toring sys tems of was te reuse . Health education of the public would need to be incorporated in waste reuse programmes . The use of raw sewage for irrigat ion , somet imes practi s ed in small towns , needs to be prohibi ted .

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EM/INC . SEM.WWR/ 17 page 1 3

5 . 27 . · Country presentation . Sudan (Dr Bash ir M . El Hassan) : Sudan is a very dry country with the Nile be ing the most important water source . The Public Health Act of 1975 prohibits the reuse of raw sewage . Khartoum has two sewage treat-ment plants . The effluent from the Khartoum South plant (8 mi llion ga llons/day)

is used for irrigation of a tree plantat ion in a green be l t

in

the south . The eff luent from the Khartoum �orth plant (6 . 5 m i l l ion gallons/day) was intended for irrigat ion . Only the f irst phase o f the stabi l i zation ponds has been

completed to date and the farmers are refusing to use the effluent for i rrigation , primari ly because of industr ial waste products in the e ffluent . ln one case , effluent from a treatment pl ant (26 m3/d , 80 ppm BOD) is be ing u�ed for sugarcane irrigation. Sludge is be ing s old to fanners and there are plans for ·produc tion of 1 0 000 m3/d of biogas in Khartoum . No epidemiological studies have been carr ied out on health hazards from wastewater reuse .

5 . 28. Country presentat ion , Tunisia (Mr Sadok Atallah): Tunisia is a country of some 6 800 000 inhab itant s evenly spl i t between urban and rural areas . The water supply is 70% by piped systems with 30? of the population served by

sanitary sewers . Planning for supply , treatment and potential reuse of waste water has progressed quite f ar, with nat ional standards already prepared for adoption. The standards are such that irrigation with treated wastewater should not represent a risk to health or present a nuisance to the surrounding area . Irrigation o f vegetables eaten raw with wastewater is prohibited . All wastewater to be used in agriculture must be treated and its use author ized by the

Minis tries of Agriculture and Public Health . Some direct reuse of raw sewage s t i l l exists but this practice has been s ignif icant ly reduced in recent years . Several pi lot proj ects are currently be ing implemented . Golf cours e irrigation is undertaken using eff luent from Sousse North wi th 7 ha be ing watered . Ten hectares of oran�es are being i rrigated in Nabeul with secondary eff luent . An

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6. WORKING GROUP DISCUSSIONS

Afte r the presentation of papers in plenary session was completed, the participants were divided into three working groups (Annex IV) • . Each group comprised five or six country representatives, and one or two members of the WHO Secretariat.

The working groups were charged with the task of identifying and discussing the specific elements and issues of the reuse of treated wastewater: Engineering Aspects, Health Aspects and Economic Aspects. They were required to formulate guidelines and plans of action in the field of wastewater reuse in the Eastern Mediterranean Region. The topics considered are listed in Annex V.

When consensus had been reached. the rapporteur of each working group St.mllllarized the conclusions at the f inal plenary session.

7. FINAL PLENARY SESS-ION

The consolidated conclusions and recommendations of the working groups were discussed in the plenary session and, after finalization, they were approved and adopted.

The meeting was then closed. 8. CONCLUSIONS AND RECOMMENDATIONS

1. A treated wastewater reuse programme should be integrated with national plans for water supply, sanitation and environmental pollution control activities.

2. In the development of controlled wastewater reuse prograrranes, governments should consider the followin� factors aimed at safeguarding public health : 2. 1. Inte rim standards

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EM/ INC .SEM. WWR/ 17

page 15

Arpl i cat ion of untreated sewage to crops meant for human consumption is clearly unaccep table and the app l icat ion of convent ional ly-treated sewar,e to raw-eaten crops cannot be recommended .

Interim standards t o regulate the reuse of wastewater, based on avai lable knowledge and legislat ion , shou ld be establ ished with the purpose of prevent in� practices endanger ing human health .

2 . 2 . Data collection and analysi�

Ep idemiological studies t o evaluate health risks should be undertaken in communit ies current ly prac t ising or planning wasteyate·r reuse .

- An inventory should be prepared of the potential for agricultural reuse , taking into account the c l imat e . soi l charac teri st ics , irrigat ion prac t ices , types of crop current ly grown and the potent ial e ffects of a l l these variables on human heal th .

An _{inventory of the resource base , 1n terms of funds and manpower}

available for the deve lopment and operat ional maintenance of sewage t reatment and reuse facil ities should be prepared . Particular emphas is should be placed on t he qual ificat ions of operators of these facilities, including monitoring and control personnel .

2 . 3 . Standards

Standard s should be formulated on the basis of the knowledge and experience ga ined from the studies ment ioned .

�rorn the health point of view, the following elements should be considered in deve lop ing standards :

I rrigation should b e restricted unless the reliabi l i ty o f the treatment system can be guaranteed for the removal of pathogens and toxic chemicals . - The health effects of sprinkler irrigation, particularly in relation to

aerosol droplet formation , should be careful ly invest igated.

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WH0-EM/ES/3Sl E?-t/INC. SEM.WWR/ 17 page 16

- Health education programnes for operators of facilities for treatlll!nt and for users of the wastewater should lbe designed and implemented. - The health of reuse system operators and product users should be kept

under surveillance.

- A protective buffer zone should be maintained between irrigated fields and residential areas, to avoid potential health problems:

2. 4. Aquifer recharge

- Before the issuance of a permit for aquifer recharge with treated waste water, a careful investigation of soil strata and groundwater hydrology should be carried out.

- Minimum requirements for effluent quality should be determined by

existing and potential uses of the aquifer, and special attention should be given to persistent, potentially-hazardous chemicals.

2 . 5 . WHO Support

The following actions were recommended :

- WHO should consider facilitating the exchange of knowledge among national governments in the Region and between these governments and international agencies through the collection and dissemination of relevant information , upd ating of e'Xl;)ert committee guidelines on wastewater reuse, organization of workshops and seminars at the national, regional and international levels, and the production of information material to make senior administrators and government officials aware of the advantages and potential problems associated with wastewater reuse.

- WHO should consider providing assistance in human resource development by supporting practical training programmes at all levels.

- WHO should consider promoting research on reuse to facilitate the introduction of national standards in the Region, particularly in relation to virological quality and disinfection and to assess the priority health hazards through epidemiological studies and the

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3. National Policy

EM/INC .SEM.WWR/17 page 17

3. 1. There is a need for nat1onal conmitment to a wastewater reuse programme as an integral part of the national water plan.

3. 2. Water resource planning must incorporate water supply, �astewater collection and treatment, and effluent reuse an an integrated system to ensure the most efficient use of available resources.

3. 3. tn the Eastern Mediterranean Region , wastewater reuse should be encouraged using sound, tested engineering practices and with consideration for

environmental protection.

3. 4. The type of reuse should be relevant to and serve the interests of the Cotm1unity concerned.

3.5. Maximum coordination, cooperation and information exchange should be encouraged at local , national, regional and international levels in developing wastewater reuse programnes.

3. 6. The availability of alternative water resources and the relationship of supply and demand will affect the national policy decision on wastewater reuse.

3.7. The econanic advantages of integrating wastewater reuse into national water planning should be assessed and emphasized.

3.8. The econanic dimension of reuse in agriculture is primarily related to

the national need for food production, ·but land protection will also provide an incentive in many countries of the Region.

3.9 . If there is no major requirement to produce food in a country, then the econanic incentive will relate to the existing policy on pollution control ; if vastewater collection and treatment is the policy, the incremental cost of upgrading effluent for reuse will normally be justifiable in arid areas. 3. 10. Reuse benefits are unlikely to justify wastewater collection and treatment

costs without public pressure for improved sanitation and pollution control, unless there is an extreme shortage of water resources.

4. Progranme Planning

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WH 0-Dt/ES / 3 51 EM/INC. SEM.WWR/17 page 18

projects. Important variables influencing cost are : the length of sewer; the distances between the collection area, the treatment plant and the reuse area; and site topography and geology.

4. 2 . Consideration should be given to separate collection syst�ms and treatment plants as well as to combined systems, depending on the population distribu tion in an area and the location of potential reuse sites.

4. 3. Prior to initiating large-scale wastewater reuse projects, it is recommended that laboratory and pilot scale studies be undertaken to gain experience and optimize the treatment/irrigation system to site-specific -conditions. 4. 4. Wastewater reuse planning, implementation and operation should recognize

and adopt technology appropriate to the country concerned and take advantage of local experience and techniques.

4. 5. Best site-specific engineering and agricultural practices must be implemented to ensure proper wastewater treatment and application, efficiently utilizing the effluent and preventing contamination of groundwater.

4. 6. The decision on treatment technology will depend on the obj ective, whether it is the disposal of the waste or the reuse to meet water demands.

4. 7. Unrestricted reuse in irrigation will incur a high cost of treatment, ·which will maintain health risk at an acceptable level.

4. 8. It should be recognized that there is a trade-off between investment in treatment for reuse (preventive) and the potentially high cost of curative health measures in the event of an outbreak resulting from poor system control or pollution from effluent discharge into water sources.

4. 9 . Each reuse plan should provide for an impact assessment prior to, during and after proj ect implementation.

4. 10. The degree of wastewater treatment should be dictated by the final use of effluent as well as health safety requirements.

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EM/INC. SEM.WWR/17 page 19

4.12. Low-cost appropriate technology applied to reuse would be economically beneficial and could also reduce the health risk. Wastewater stabiliza tiJi ponds, for example, are very effective in removing pathogens and parasites and will be inexpensive where land cost is reasonable.

4. 13. The quality of effluent, and therefore the cost of treatment, will also be influenced by the irrigation method chosen. Choice of irrigation method will depend on the volume of available effluent .

4. 14. Selection of crops should maximize the economic return from the available water resource while maintaining health standards.

4. 15. Industrial discharges should be pretreated before disposal to municipal wastewater collection systems to minimize the introduction of ha2ardous substances.

s.

Programme Implementation

5. 1. There must be close coordination and cooperation among all the agencies and sectors involved in reuse programne implementation.

�. 2. Stringent monitoring of all components of wastevater reuse systems, the treated effluent, the land and the product, must be implemented and maintained to detect adverse effects and ensure reuse project viability. 5.3. Quantitative and qualitative control of reuse systems will require careful

consideration and investment in personnel and laboratory facilities. often in more than one government agency.

5.4. Wastevater treatment processes adopted should always ensure a consistent and reliable effluent quality.

S . S. In reuse programmes, the degree of sophistication of the treatment plant will have an effect on the training requirements for operating personnel and therefore on the cost of national training programmes.

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WHO-EM/ES/351 E}f/INC . SEM. WWR/ 17 page 20

ACKNOWLEDGEMENT

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EASTERN MEDITERRANEAN REGION

BAHRAIN

EGYPT, ARAB REPUBLIC OF

JORDAN

KUWAIT

*

_{Could not attend}

LIST OF PARTICIPANTS

Mr Ali Jaffar Anjawi

EM/INC. SEM.WWR/17 page 21

Head of the Environmental Heal th Department and Assistant Director of Public Heal th

Public Health Directorate Ministry of Health

Manama

Dr Maher Hanna Danial Director, Water Section Central Laboratories Ministry of Health Cairo

*

Dr Ezzat Mohammed Helwa Acting Director-General

Environmental Health Department Ministry of Health

Cairo

Mr MohaDllllad Hussein Dajani

Director, Environmental Health Division Ministry of Health

Amman

Mr Ahmad Abdul Rahman S.A. Hadidi Manager

Amman Wastewater Treatment Plant Amman

Dr Shaaban Amin El-Hadary Chief, Environmental Health Preventive Medicine Division

Department of Public Health & Training Ministry of Health

Kuwait

Mr Hamad Sanad Essa Al Matar Chemical Engineer

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WHO-F.M/f'.S/3 5 1 EM/INC . SEM . WWR/ 1 7 page 22 OMAN. SULTANATE OF * PAKISTAN * QATAR SAUDI ARABIA

SUDAN, DEMOCRATIC REPUBLIC OF

TUNISIA

* UNITED ARAB EMIRATES AFRICAN REGION

*

ALGERIA

Unable to att end

Mr Al i Bin Mohammed Al Rashtly Senior Sani tary Supervisor ( in charge of wastewater) Environmental Health Sec tion Department of Preventive Med icine Minis try of Heal th

Muscat

Mr Emran M. Amin Ka tib

Direc tor of Environmental Heal th Depar tmenr Minis try of Public Heal th

Riyad

Mr Yusri Ali Hassan

Chief, Public Heal th Engineering

Ministry of Construc tion and Public Works Khar toum

Dr Bashir Mohamed El Hassan Dean

School of Hygiene Khartoum

Mr Sadak Atallah

Direc tor , Environmental Health Depar tment Ministry of Public Heal th

Tunis

Mr Said Ben Sl ima Deputy Direc tor

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EUROPEAN REGION MOROCCO

OTHER UN AGENCIES

FOOD & AGRICULTURE ORGANIZATION OF THE UNITED NATIONS (FAO)* UNITED NATIONS ECONOMIC CO�IMISSION

FOR WESTERN ASIA (ECWA)*

UNITED NATIONS ENVIRONMENT PROGRAMME (UNEP)

REGIONAL OFFICE UNEP (BAHRAIN)

OBSERVERS FROM HOST GOVERNMENT

Unable to attend Mr Fouad Marrakchi Sanitary Engineer Ministry of Health Rabat * Mr Azizi Sanitary Engineer Ministry of Health Rabat Mr Laszlo David EM/INC. SEM.WWR/17 page 23

Senior Programme Officer on Water Nairobi

Mr Salih Osman

Dir ector & Regional Representative UNEP Regional Office for West Asia Manama

Mr Ali E. Al Dalooj UNEP Regional Adviser Manama

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WHO-EM/ES/351 EN/INC. SEM. WWR/ 17 page 24

OBSERVERS FROM HOST GOVER.""Il-IBNT (cont 'd)

WHO SECRETARIAT

Mr Fouad Al-Rumaihi Bahrain Research Centr¢ Manama

Mr Fareed Ismail Bushehri Civil Service Bureau' Manama

Mr T. Zerihi Regional Adviser on Environmental Hazards & Pollution Control

WHO Eastern Mediterranean Regional Office

Mr Gunnar Schultzberg Sanitary Engineer , Environmental Health Technology & Support Mr John W. Fordham mm Consultant

Dr Sagar M. Goyal WHO Consultant

Prof. M.B. Pescod WHO Consultant

Miss A. El Didi Secret ary

WHO Headquarters Geneva

Senior Research Engineer, Water Resources Centre, Desert Research Institute, University of Nevada System USA

Assistant Professor Virology . Department of Veterinary

Diagnostic Investigation.

College of Veterinary Medicine, University of Minnesota, USA. Head,

Department of Civil Engineering,

University of Newcastle upon Tyne, UK

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ANNEX I AGENDA 1. Opening Session.

EM/INC.SEM.WR/17 page 25

2. Health Aspects of Reuse of Treated Wastewater for Irrigation. 3. Evaluation of Health Hazards of Wastewater Reuse.

4. Environmental Aspects of Wastewater Reuse. 5. Development of Wastewater Reuse Programme.

6. Wastewater Reuse and its Practical Impl ications.

7. Enteric Disease Transmission Associated with Wastewater Utilization in Agricultural Connnunities .

8 . Economics of Wastewater Reuse.

9. Appropriate Wastewater Reuse Technology.

10. Development of Methodology for Evaluating Integrated Water Reuse/ Wastewater Treatment Alternative.

11. Health and Safety Aspects of Irrigation of Raw Eaten Food with Reused Wastewater including Labour Protection.

12. Evaluation of Agricultural Irrigation Projects Using Reclaimed Municipal Wastewater.

13. Site Select ion Techniques for Land Disposal of Treated Municipal Wastewater. 14. Environmental Operat ional Guidelines for Irrigation in Arid and Semi-Arid

Regions.

15. Hea l th Aspects of Wastewater Reuse by Groundwater Recharge . 16. Conclusions and Recommendations.

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l-lHO-F.M /ES / 351 E;-1/INC . SEM . mTR./ 17 page 26 ANNEX I I PROGRAMME Sa turday, 29 September 9 . 00 - 9 . 30 9 .30 - 10.15 10 . 15 - 10 .45 10 .45 - 11 . 30 11 . 30 - 1 2 . 15 12 .15 - 13 .00 13 . 00 - 13 . 30 13 . 30 - 15 . 30

* _{The mee t ing was opened by Mr Mohammed}

Rahma Al Taj ir , Ass istant Under-Secretary for Admin istra tion and Planning Affairs

Registration Opening Session: - Holy Koran rec ital

- Address by H . E . The Min�ster

*

of Health (or his representa tive) - Message from Dr Hussein A. Gezairy,

Regional Direc tor , WHO Regional Office for the Eastern Med iterranean

Recess

Introduc tion to the Group Meeting : Obj ec tives and adminis trative arrangements

Heal th Aspec ts of Reuse of Treated Wastewater for Irriga tion (WHO/EMRO Document)

- presenta tion by Mr T. Zeribi Evaluation of Heal th Hazards of Was tewater Reuse

- presentation by Mr G. Schultzberg , WHO Headquar ters

Country presenta tion , Oman Recess

Environmental Aspec ts of Wastewa ter Reuse - presentation by Mr L . David , UNEP/

Nairob i

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Sunday, 30 _September 8 . 00 - &.45 8.45 - 9 . 30 9 .30 - 1 0 . 15 10.15 - 10.45 10.45 - 11 . 30 11 . 30 - 12 . 1 5 lS.. 30 - 18. 30 Monday, 1s t _October 8 . 00 - 8 .45 8.45 - 9 . 30 9 . 30 - 10.15 EM/ INC . SF.M,mlR./ 17 page 27

Development of Wastewater Reuse Programme

presentation by Mr J. W. Fordhams

WHO Consultant

Wastewa ter Reuse and its Prac tical

Implications

- presenta tion by Professor M .B. Pescod , WHO Consultant

Country presentation, Saudi Arabia

Recess

Enter ic Disease Transmission Assoc ia ted

with Wastewater Utiliza tion in Agricul tural Communities

- presentation by Dr S .M . Goyal1

WHO Consul tant

Economics of Wastewater Reuse

- presentation by Professor M.B. Pescod ,

WHO Consultant

Field Visit to Wastewa ter Treatment Plant

at Tubli

Appropriate Wastewater Reuse Technology

- presentation by Professor M . B . Pescod ; WHO Consul tant

Development of Methodology for Evaluating Integrated Water Reuse/Wastewater Treatment

Alternative

- presentation by Mr J.W. Fordham

WHO Consultant

Heal th and Safety Aspec ts of Irrigation

of Raw Eaten Food with Reused Wastewa ter including Labour Protection

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WHO-EM/ES/351 F.l-1/ INC. SEM. WWR/ 17 page 28

Monday, 1s t _{October (Cont'd)}

10 . 15 - 10.45 10 .45 - 11 .30 11 . 30 - 12 . 15 12 .15 - 13 .00 13 . 00 - 14 . 30 13 . 00 - 13 . 30 14 . 30 - 15 . 00 Tuesday1 2nd Oc tober 8 . 00 - 8 . 45 8 .45 - 9 .45 9 . 45 - 1 2 . 00 1 2 . 00 - 12 .45 12 .45 - 15 .00 15 .00 - _16.00 Recess

Country presenta tion, Morocco

Evalua tion of Agricul tural Irrigation Projects Using Reclaimed Municipal Was teYa ter

- presenta tion by Mr J .W. Fordham WHO Consultant

Site Selection Techniques for Land

Disposal of Treated Municipal Was tewater - presenta tion by Professor M.B. Pescod

WHO Consul tant

Country presentations , Tunisia and Kuwait

Recess

Environmental Operational Guidel ines for

Irrigation in Arid and Semi-Arid Regions

- presentation by Mr J .W . Fordham WHO Consultant

Health Aspects of Was tewa ter Reuse by

Groundwater Recharge

- presenta tion by Dr S .M . Goyal , WHO Consultant

Country presentations , Jordan and Egypt

Joint meeting between the three working

groups Recess

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ANNEX Ill

LIST OF BACKGROUND DOCUMENTS

EM/INC . SEM .WWR/ 17 page 29

1 . Human Viruses in Water, Wastewater and Soil , Technical Report Series No .639 -World Heal th Organiza tion, Geneva, 1979

2 . Reuse of Effluents : Method:;; of -tfas t�ater Tre3tment and Health Safeguards , Technical Report Series No . 517 , World Heal th Organiza tion, Geneva , 1973 3 . The Risk to Heal th of ?1icrobes ·in Sewage ·Sludge Applied to Land , EURO Repor ts

and Studies No .54 , World Health Organiza tion, Copenhagen

4 . Heal th Aspec ts of Trea ted Sewage Reuse , EURO Repor ts and Studies No .421

World Heal th Organization, Copenhagen

5 . Repor t on "Public Health Aspects of Night Soil Utiliza tion", Na tional Seminar on Hygienic Trea tment and Use of Nightsoil , 7 - 19 December 1981 , Beij ing , by : Dr D . Barua , WHO Consul tant

6 . UNDP - Integra ted Resource Recovery, Was te Recycling - A global research, development and demonstra tion project of the United Nations Development Programme (GL0/80/004 ) , July 1981 , The World Bank - Executing Agency

7 . "Increase in Die tary Cadmium as a Result of Application of Sewage Sludge to Agricul tural Land", extract from American Chemical Society , Vol .15, No . 8 , August 1981 .

8. "Effect of Liquid Wastewa ter Sludge Applica tion on Crop Yield and Wa ter Quali ty", extract from Journal Water Pollution Control Federation (WPCF) , Vol . 54 , No . 8

9 . "Denver Demons trates Direct Reuse to a Thirs ty Public", extract from Water/ Engineering & Management, May 1984

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WHO-EM/ES /351 EM/INC. SEM.WWR/17 page 30

ANNEX IV

WORKING GROUP MEMBERS Working Group I (Engineering Aspects)

Participants WHO Secretariat Observers Dr Bashir M. El Hassan Mr Sadok Atallah Mr Ali B.M. Al Rashdy Mr Ahmed A.R. Hadidi Mr Fouad Marrakchi Mr John W. Fordham Mr Fouad Al-Rumaihi Working Group II (Heal th Aspects)

Participants

WHO Secretariat Observers

Dr Shaaban Amin El-Hadary Mr Emran M. Amin Katib Mr Ali Jaffar Anj awi Mr Mohammad H. Daj ani Dr Maher Hanna Danial Hr Gunnar Schultzberg Dr Sagar M. Goyal Mr Fareed I. Bushehri Working Group III (Economic Aspects)

Participants

WHO Secretariat Observers

Mr Hamad S.E. Al Matar Mr Yusri Ali Hassan Mr Said Ben Slima Mr Ali Aldalooj Prof. M.B. Pescod Dr T. I. Emecz Working Groups Coordinator : Mr T. Zeribi

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ANNEX V