international standard and guidelines : health and agriculture aspects 1 ecological sanitation...

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Ecological Sanitation Symposium, Syria, 11 -13 December 2005

International Standard and Guidelines: Health and Agriculture Aspects

Christine WernerDeutsche Gesellschaft für Technische Zusammenarbeit (GTZ) GmbH

ecological sanitation program, Division 44 – environment and infrastructure

(Ecological Sanitation Symposium, Syria, 11-13.12.2005)

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Contents

WHO Guidelines 1989 version: Guidelines for the safe use of wastewater

and excreta in agriculture and aquaculture 2005 version (upcoming): Guidelines for the safe use of

wastewater, excreta and greywater

EcoSanRes Guidelines Guidelines on the safe use of urine and faeces in

ecological sanitation systems Guidelines on the use of urine and faeces in crop

production

FAO Guidelines FAO irrigation and drainage paper 47: wastewater

treatment and use in agriculture (1992)

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WHO guidelines for the safe use of wastewater and excreta in agriculture and aquaculture (1989)

Category UsePerson / Group

exposed

Nematodes[Eggs / kg]

Feacal coliforms[number /

100 g]

AApplication to field crop (used for raw

food)

worker, consumer,

public</= 1 </= 1000

BApplication to field crop (for industrial

use, feedstock, trees)worker </= 1

no suggested standard

C

Local application to field crop of cat. B, without contact to

persons

none not relevantnot

relevant

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Upcoming WHO guidelines, update of the guidelines from 1989, publication planned in 2006

3 Volumes: safe use of wastewater in agriculture safe use of wastewater in aquaculture safe use of excreta and greywater

New WHO guidelines for the safe use of wastewater, excreta and greywater

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Reuse of wastewater, greywater and excreta in agriculture and aquaculture is practiced worldwide on a large scale, however often without sufficient health proctction measures

WHO recognise the importance of reuse of wastewater, greywater and excreta for sustainable food production and improved livelihood

WHO provides guidance on health protection measures for safe reuse

WHO recognise source-separation as a special and valid approach

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The new WHO-guidelines are:

…based on: scientific consensus

and best available evidence,

health based targets good practices and a

multiple-barrier approach

…to be adapted to local social, economic, and environmental factors

…striving to maximize overall public health benefits and the beneficial use of scarce resources

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new WHO guidelines for the safe use of wastewater, excreta and greywater

key issue: better methodologies for evaluating risk previous guidelines were based

on actual risks using epidemiological evidence

updated guidelines make use of all available evidence including Quantitative Microbial Risk Assessment (QMRA-models)

data on different pathogens are used to develop health based targets, required pathogen reduction

and miocrobial performance

targets of wastewater and excreta treatment systems

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Definition: Disability Adjusted Life Years (DALYs) DALYs are a measure of population health in terms of the burden

due to a specific disease or risk factor. DALYs attempt to measure healthy years of life lost because of

disability or death from a disease DALYs account for not only acute health effects but also for delayed

and chronic effects different health outcomes (e.g., cancer vs diarrhea) can be

compared and risk management decisions can be prioritized.

adopted protection level for wastewater/excreta use in agriculture in the new WHO guideline:

tolerable additional disease burden <= 10-6 DALYs or 1 µDaly per person and year= only one of a million human life years expectancy will be

lost due to the potential additional disease from wastewater/excreta reuse

= same protection level as used in the WHO guideline fordrinking water

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Pathogen reductions achievable by various health protection measures for wastewater use in agriculture

Control measure Pathogen reduction (log units)

Wastewater treatment 1−6

Localized (drip) irrigation (low-growing crops)

2

Localized (drip) irrigation (high-growing crops)

4

Spray drift control (spray irrigation) 1

Spray buffer zone (spray irrigation) 1

Pathogen die-off 0.5−2 per day

Produce washing with water 1

Produce disinfection 2

Produce peeling 2

Produce cooking 6−7

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Verification monitoring of wastewater treatment for the various levels of wastewater treatment in Options A−G: E.coli

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Health-based targets for treated wastewater use in agriculture: helminth eggs

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Example: agricultural use of wastewater, Peru

Coastal region of Peru: extremely arid Wastewater treatment in stabilisation ponds Irrigation with treated effluent for restricted crops

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Example: greywater recycling through sub-surface application, India

Use of greywater in mulch trenches

Mulch filled trench or pit

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Guidelines on the safe use of urine and faeces in ecological sanitation systems (EcoSanRes)

public health issues of agricultural reuse of urine and faeces

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guidelines on the safe use of urine and faeces in ecological sanitation systems (EcoSanRes)

focuses on the treatment and handling of faeces and urine, provides current information on risk management and assessment of source separation strategies

technical and behavioural barriers against disease transmission, sanitation treatment methods, reuse in agriculture

the scope of guideline is limited to products from urine diversion devices and dry collection systems for faeces.

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Recommendations for urine treatment and use: The main risks in the use of excreta are related to

the faecal fraction and not the urine fraction. Technical constructions should be done in ways to

minimize faecal crosscontamination. At household level the urine can be used directly. Urine should, in large-scale systems, be stored for

one month at 20°C before use. A withholding period of one

month between fertilization and harvest should be applied.

Urine should be applied close to ground and preferably mixed with or watered into the soil.U

rine

stro

gae

in S

wed

en (

Geb

ers)

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Recommendations for faeces treatment and use: Faeces should be treated before use as fertilizer. Primary treatment (in the toilet) includes storage and

alkaline treatment by addition of ash, lime or urea. 1-2 cups (200-500 ml; enough to cover the fresh

faeces) of alkaline material should be added after each defecation.

Faeces should additionally be mixed into the soil in such a way that they are well covered.

Faeces should not be used for fertilization of vegetables, fruits or root crops that are to be consumed raw, excluding fruit trees.

Drie

d fa

eces

(G

TZ

))

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Treatment Criteria Comment

Storage (only treatment) at ambient temperature 2-20°C

1,5-2 years

Will eliminate most bacterial pathogens, substantially reduce viruses, protozoa and parasites, some ova may persist

Storage (only treatment) at 20-35°C

>1 year As above

Storage and alkaline treatment

pH >9during > 6

months

Temperature <35°, moisture content >25° or lower pH will prolong the time for absolute elimination

Recommended storage time and treatment for faeces

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Guidelines on the use of urine and faeces in crop production (EcoSanRes)

Agronomic issues of agricultural reuse of urine and faeces

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Requirements regarding re-using of excreta for agricultural purposes, including plant growth, nutirents in excreta, hygiene treatment of urine and faeces, etc. are discussed.

Recommendations on using excreta in cultivation are given.

It emphasizes that urine and faeces are complete fertilizers. Urine is rich in nitrogen and faeces are rich in phosphorous, potassium and organic matter.

guideline is limited to products from urine diversion devices and dry collection systems for faeces.

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Recommendations for use of urine in cultivation:

Urine is a quick-acting nitrogen-rich complete fertilizer. Best effects from prior to sowing, up until two-thirds of the period between sowing and harvest.

Recommended application rate and time should be based on the desired nitrogen application rate (based on local recommendations for chemical nitrogen fertilizers)

Rule of thumb: apply the urine from one person during one day (24 hours) to one square metre of crop. (= 300-400 m2 per person and year)

Fot

os:

Urin

e re

use

in H

avan

na,

Cub

a (G

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Recommendations for use of faeces in cultivation:

Faeces should be applied and mixed into the soil before cultivation starts. Local application in holes or furrows close to the planned plants allows for economic use

The application rate can be based on the current recommendation for the use of phosphorous-based fertilizers (low application rate with little improvement due to the added organic matter)

Faeces can also be applied at much higher rates for improving structure and water-holding capacity of the soil

Fot

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Com

post

fro

m f

aece

s in

Hav

anna

, C

uba

(GT

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Beneficial effects of agricultural use of urine and faeces

restored soil fertility through nutrient reuse

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003

improved soil quality through reuse of organics

urinefaeces & urine

none

compost improved soil untreated soil

after one week without water

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Jens

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Covers health aspects and agronomic aspects of reuse of wastewater in agriculture

Draws on the WHO Guidelines (1989) for health protection measures

FAO irrigation and drainage paper 47: Wastewater treatment and use in agriculture

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FAO irrigation and drainage paper 47: Wastewater treatment and use in agriculture

FAO guidelines define use restrictions with respect to salinity, trace elements, nitrogen, etc. in order to not produce negative effects on productivity and yields.

Blending conventional water with treated effluent, or using the two sources in rotation is possible.

This means that nutrients elimination in wastewater treatment is not necessary if reclaimed water can be blended with normal irrigation water.

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FAO irrigation and drainage paper 47: wastewater treatment and use in agriculture

units Degree of restriction on use

none Slight to moderate

severe

Potential irrigation problem

Salinity (Ecw1 ) dS/m < 0.7 0.7 - 3.0 > 3.0

Na, surface irrigation me/I < 4 4 - 10 > 10

Na, sprinkler irrigation m3/l < 3 > 3

Nitrogen (NO3-N)3 mg/l < 5 5 - 30 > 30

pH Normal range 6.5-8

Water quality guidelines for maximum crop production (example)

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FAO irrigation and drainage paper 47: wastewater treatment and use in agriculture

Element Recommended maximum

concentration (mg/l)

Remarks

Cd 0.01 Toxic to beans, beets and turnips at concentrations as low as 0.1 mg/l in nutrient solutions. Conservative limits recommended due to its potential for accumulation in plants and soils to concentrations that may be harmful to humans.

Cu 0.20 Toxic to a number of plants at 0.1 to 1.0 mg/l in nutrient solutions.

Zn 2.0 Toxic to many plants at widely varying concentrations; reduced toxicity at pH > 6.0 and in fine textured or organic soils.

Pd 5.0 Can inhibit plant cell growth at very high concentrations.

Threshold levels of trace elements for crop production (example)

international standard and guidelines : health and agriculture aspects 1 ecological sanitation...

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