Constituent
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Measured Parameters
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Reasons for Concern
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Suspended Solids
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Suspended solids (SS), including volatile and absorbed on particulates.
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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.
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Biodegradable Organics
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Biochemical oxygen demand,
chemical oxygen demand, total organic carbon
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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)
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Nutrients
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Nitrogen, Phosphorus, Potassium
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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 EPA document)
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Stable Organics
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Specific compounds (e.g., pesticides, chlorinated hydrocarbons)
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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)
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Hydrogen Ion Concentration
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pH
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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 significantly.
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Heavy Metals
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Specific elements (e.g., Cd, Zn, Ni, and Hg)
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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.
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Dissolved Inorganics
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Total dissolved solids, electrical Conductivity, specific elements (e.g., Na, Ca, Mg, Cl, and B)
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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).
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Residual Chlorine
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Free and combined chlorine
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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)
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