||Reasons for Concern
||Suspended solids (SS),
including volatile and
absorbed on particulates.
|Organic contaminants, heavy metals, etc. are
absorbed on particulates. Suspended matter can
shield microorganisms from disinfectants.
Excessive amounts of suspended solids cause
plugging in irrigation systems.
|Biochemical oxygen demand,
chemical oxygen demand,
total organic carbon
|Aesthetic and nuisance problems. Organics
provide food for microorganisms, adversely affect
disinfection processes, make water
unsuitable for some industrial or other uses,
consume oxygen, and may result in acute or
chronic effects if reclaimed water is u (end is
missing from EPA document)
|Nitrogen, phosphorus, and potassium are essential
nutrients for plant growth and their presence
normally enhances the value of the water for
irrigation. When discharged to the aquatic
environment, nitrogen and phosphorus can lead to
the growth of undesir (end is missing from
||Specific compounds (e.g.,
|Some of these organics tend to resist conventional
methods of wastewater treatment. Some organic
compounds are toxic in the environment, and their
presence may limit the suitability of reclaimed water
for irrigation or other uses. Chlorine reacts with
man (end is missing on EPA document)
||The pH of wastewater affects disinfection,
coagulation, metal solubility, as well as alkalinity of
soils. Normal range in municipal wastewater is pH =
6.5 - 8.5, but industrial waste can alter pH
||Specific elements (e.g.,
Cd, Zn, Ni, and Hg)
|Some heavy metals accumulate in the
environment and are toxic to plants and animals.
Their presence may limit the suitability of the
reclaimed water for irrigation or other uses.
||Total dissolved solids,
specific elements (e.g., Na,
Ca, Mg, Cl, and B)
|Excessive salinity may damage some crops.
Specific inorganics electrical conductivity ions such
as chloride, sodium, and boron are toxic to specific
elements (e.g., in some crops, sodium may pose
soil permeability Na, Ca, Mg, Cl, and B problems).
||Free and combined chlorine
||Excessive amounts of free available chlorine
(>0.05 Chlorine chlorine mg/l) may cause leaf-tip
burn and damage some sensitive crops. However,
most chlorine in reclaimed water is in
a combined form, which does not cause crop
damage. Some concerns are expre (end
missing on EPA document)