Impact of Reclaimed Water Based Irrigation on the Concentration of Chemicals of Emerging Concern in the Irrigated Area

Basics

• This page is largely in a USA Regulatory Environment based context, feel free to add more information/clarify however!
• As of 2026, Most Chemicals of Emerging Concern (essentially “new (mainly anthropogenic) things that may be fine, or may be novel pollutants, but the science hasn’t figured out yet) aren’t regulated
  • Thus while Reclaimed Water is VERY clean in terms of:
    • Turbidity (How clear the water is)
    • Biochemical Oxygen Demand (Mainly “will it cause an algae bloom/a fish kill if you dump it in a river?
    • Other “Conventional” Specs like PH, Salinity, Hydrocarbons, Heavy Metal Pollutants, Dioxins, etc
  • It may contain trace amounts of PFAS / other “Forever Chemicals” that may accumulate, ESPECIALLY in prolonged irrigation
    • Use of Human Biosolids as fertilizer (akin to Non-Human Animal Derived Manure ) had this problem, numerous farms were too PFAS contaminated to be usable without years of crops being sent to disposal as Phytoremediation etc
  • ALTHOUGH given this was the solids fraction, concentrations of pollutants may be far higher
    • Especially if certain Flocculants / Chelating Agents are added before the Clarifier (Wastewater Treatment)

Preventative Measures / Polluter Side Solutions

• Essentially as a final (or next to final, if using a UV Sterilization Stage), have a Granulated Activated Carbon Liquid-Solid Contactor of some sort, and POTENTIALLY some sort of filtration
  • Need to check existing literature on this, but GAC (especially if “overbuilt” and well maintained) should adsorb all of the “nasties”, which can then be sent to disposal (Via Incineration or SCWO etc)
  • Sampling+Monitoring would also be of use to check for this

If doing all that, why not just reuse it?

• While Black Water Recycling makes objective sense in every manner short of POTENTIALLY cost (depending on region, ie doing so in a non-water scarce region may not make sense), the taboo may be too hard to get past in some areas
• Using Reclaimed Water for irrigation (especially when it is widely known + placards are put up saying not to drink it etc) is far easier to get people onboard for, while preventing that use from using Potable Water
  • It also would prevent needing to discharge it into a stream, or worse yet use an Injection Well / Disposal Well (ie the disposal route, not Aquifer Recharge technology of Aquifer Storage and Recovery )