TheWorld Health Organization's criteria for effluent application for agricultural irrigation

Constituents

(mg/1)

 

 

 

Group A
Irrigation of crops to be eaten uncooked

Group B
cereal crops, industrial crops, fodder crops, pasture and trees

Group C
Localized irrigation of crops in category b if exposure of workers and the public does not occur

Effluent quality

Intestinal nematodes (arithmetic mean no of eggs per liter)

Coliform Counts/100 ml



<1


<1000

 

<1


No Standard

 

N/A


N/A

Mandatory treatment
Stabilization pond

Equivalent water treatment
plant


required

required

-


required
8-10 days retention time
N/R


N/R

N/R

Pretreatment needed by irrigation technology  or primary sedimentation

Wastewater can be applied to the land using flood irrigation which probably exposes field workers to the greatest risk. Sprinkler irrigation should not be used on vegetables and fruit unless the effluent meets the guideline for Category A conditions  and flood irrigation should not be  used for vegetables. Subsurface of localized irrigation when the surface is covered with plastic mulch gives the greatest degree of health protection.