Reclaimed Water is Coming to my Town — Is my Drinking Water Safe?

Lake PictureIntro­duc­tion to Recy­cled Water

Let’s start this dis­cus­sion by going over the two pri­mary types of reuse. The first and most com­mon is indi­rect reuse. Indi­rect reuse occurs when waste­water (in the US this is typ­i­cally treated to a high level) is dis­charged to a stream or lake. The mixed water then flows down­stream where some­one pulls is back out for drink­ing water. What is dif­fer­ent today is that indi­rect reuse now includes now includes inject­ing treated waste­water into ground­wa­ter sources and remov­ing mixed waste­water and river water from the stream and pump­ing back upstream to a lake where it even­tu­ally becomes the raw water for a water treat­ment sys­tem. Direct Reuse is when treated waste­water is used for a ben­e­fi­cial use with­out first mix­ing with nat­ural waters. This com­monly used for irri­ga­tion of golf courses, play­ing fields, cool­ing tow­ers, hydraulic frac­tur­ing and other cre­ative uses. This is the most cost-effective reuse method since it does not need the extra pump­ing and treat­ment needed for indi­rect reuse. This arti­cle will focus on some of the issues asso­ci­ated with indi­rect reuse since it often the method that raises the most con­cern since the waste­water becomes part of the potable water source water.

Pathogens

If your source water is from a lake or river, you have prob­a­bly already been drink­ing some reclaimed water. Many water intakes are down­stream of at least one waste­water treat­ment plant dis­charge point. This type of indi­rect reuse has been occur­ring for hun­dreds of years. Nat­ural sur­face waters already con­tain large amounts of bac­te­ria and virus orig­i­nat­ing from wildlife, domes­ti­cated ani­mals, birds and humans. In areas with good waste­water treat­ment, pathogens orig­i­nat­ing from humans is typ­i­cally low with the main source being wildlife, birds and pets.

One study you may want to look at is the Final Draft Tech­ni­cal Sup­port Doc­u­ment Seg­ments 0806, 0841, 0822, and 0805 of the Trin­ity River Bac­te­ria TMDL, Jan­u­ary 2008. TMDL is Total Max­i­mum Daily Load and rep­re­sents the max­i­mum amount of a pol­lu­tant that the stream can receive with­out exceed­ing a given water qual­ity stan­dard. As part of this study, Bac­te­r­ial Source Track­ing (BST) was per­formed on E. coli strains to iden­tify the source of bac­te­ria in the stream seg­ments. The BST process con­sid­ers genetic and bio­chem­i­cal tests to iden­tify the host ani­mal. A sum­mary of the results for Seg­ment 0806 are shown in the fol­low­ing table. This data is taken from Table 3–3 of the TMDL report.

 

Cat­e­gory

Source

Con­tri­bu­tion

Avian

Avian 23.4
Water­fowl 4.6
Subto­tal 28

Human

Sewage 0.6
Waste­water 10.7
Subto­tal 11.3

Live­stock

Bison 0
Bovine 1.4
Don­key 0
Equine 0.3
Goat 0.3
Horse 1.7
Subto­tal 3.8

Wildlife

Armadillo 0.6
Coy­ote 0
Deer 0
Opos­sum 1.7
Rab­bit 0.3
Rac­coon 6.6
Rodent 11.6
Skunk 0.9
Squir­rel 1.2
Subto­tal 22.8

Pet

Canine 2
Cat 1.7
Dog 9
Feline 0.6
Subto­tal 13.3

Unknown

Unknown 20.8
Subto­tal 20.8

Total

100

 

This data shows just how effi­cient water treat­ment sys­tems in the US are in remov­ing pathogens. Most pathogens are nat­u­rally occur­ring in source waters and would be around even if we humans were not around. Pathogen reduc­tion was the pri­mary goal of the early water treat­ment sys­tems, and the process has become highly advanced and reli­able over the last 150 years. Except for pris­tine waters, the rel­a­tively small amount of pathogens added to water sup­plies from waste­water is a minor concern.

Chemicals/Pharmaceuticals

Another con­cern is the accu­mu­la­tion of chem­i­cals in the water sup­ply. Chem­i­cals washed into the streams from urban and agri­cul­tural storm water runoff as well as dis­charges from indus­trial and munic­i­pal waste­water plants can accu­mu­late in water sup­plies and bio-accumulate in aquatic ani­mals. Phar­ma­ceu­ti­cals and per­sonal care prod­ucts are also a grow­ing con­cern. These enter the water cycle by pass­ing through the body or being dis­posed down sinks and toi­lets. With indi­rect reuse, a por­tion of the waste­water is recy­cled back into the water sup­ply, which could lead to higher con­cen­tra­tions of these con­t­a­m­i­nants. For more infor­ma­tion, visit EPA’s web­site Phar­ma­ceu­ti­cals and Per­sonal Care Prod­ucts (PPCPs) in Water.

Many, but not all, of these chem­i­cals are reg­u­lated by the EPA and states in the drink­ing water; there­fore, there is typ­i­cally lit­tle con­cern these reg­u­lated chem­i­cals will become a prob­lem. For those chem­i­cals that are not reg­u­lated, the water util­ity will often per­form broad spec­trum ana­lyt­i­cal tests to check whether there are other chem­i­cals present that may pose concern.

Salts

Typ­i­cally, waste­water has a higher salt con­tent than the lakes and streams. As the per­cent­age of water in a lake that orig­i­nates from waste­water increases the salt con­tent can rise. This is eas­ily mon­i­tored in both the treated waste­water and the lakes. High salt lev­els are more dif­fi­cult to treat and can change the taste of the water. Water util­i­ties typ­i­cally watch this care­fully and will limit the recy­cling of the waste­water if the salt lev­els begin to rise.

Nutri­ents

Another prac­tice the water util­i­ties typ­i­cally use to treat the waste­water that is recy­cled is nutri­ent removal. High ammo­nia and phos­pho­rus lev­els can lead to algal blooms in lakes and slow-moving streams. Algal blooms can kill aquatic life and cre­ate sig­nif­i­cant taste and odor prob­lems in the drink­ing water. Recy­cled water is often treated to a higher level to reduce these nutri­ents since algal blooms are hard to con­trol in the lakes.

Get Involved

If recy­cled water is com­ing to your town, get involved, ask ques­tions, go to pub­lic meet­ings and edu­cate your­self. As you con­sider the pru­dence of using recy­cled water in your area, con­sider the fol­low­ing issues.

  • Why does your com­mu­nity need to recy­cle the water? Typ­i­cally, this is due to drought and other water resource lim­i­ta­tions. Maybe the same peo­ple fight­ing reuse are also fight­ing con­struc­tion of that new lake. If a com­mu­nity does not have abun­dant water, it will not grow.
  • Exec­u­tives for the water util­i­ties often live in the ser­vice area. They will be drink­ing the same water and using it in their homes. They are hav­ing to do the best they can with lim­ited resources and money.
  • Con­ser­va­tion can help to some extent. Make sure the util­ity has a good con­ser­va­tion plan and become a cham­pion in your neigh­bor­hood. If the lakes stay full, there will be no need to recy­cle the water.
  • Ask the water util­ity for infor­ma­tional mate­r­ial. Visit the Sus­tain­able Solu­tions for a Thirsty Planet web­site and find out more.
  • Attend the pub­lic meet­ings and vol­un­teer to be a part of steer­ing committees.
  • Ask the water util­ity pub­lic rela­tions per­son to come present to your church, group or orga­ni­za­tion. They are pas­sion­ate about water and typ­i­cally enjoy the invitations.

No mat­ter if your com­mu­nity uses recy­cled water, we typ­i­cally rec­om­mend each home have a water fil­ter. See our post What type of water fil­ter do should I get for my home? for infor­ma­tion on these systems.


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