Environmental Engineering Reference
In-Depth Information
nitriication. to. be. converted. into. nitrogen. gas. (Tchobanoglous. et. al.. 2003)..
GAC.is.used.in.conjunction.with.ozone.in.such.an.advanced.water.treatment.
process.known.as.the.BAC..The.basis.of.this.treatment.system.involves.the.
use.of.ozone.as.an.oxidizing.agent,.which.causes.the.breakdown.of.POPs.and.
EDCs.into.smaller.compounds..The.formed.molecules.are.degraded.biologi-
cally. on. bacterial. biomass. that. develops. on. the. surface.of. the. AC,. whereas.
the.adsorption.of.POPs.and.EDCs.as.well.as.the.removal.of.biodegradation.
residues.could.be.achieved.through.AC.conventional.adsorption.processes..
The.removal.rate.using.BAC.is.a.combination.of.the.capability.of.ozone.oxida-
tive.degradation,.biological.degradation,.and.the.adsorptive.properties.of.AC.
(AWWARF.2007)..The.data.from.the.literature.investigating.BAC.treatment.in.
the.removal.of.POPs.and.CECs.are.summarized.in.Tables.8.13.through.8.15.
Conclusion
Wastewater.treatment.facilities.are.designed.to.meet.efluent.quality.param-
eters.such.as.TSS,.BOD,.and.COD..Most.conventional.POSTW.facilities.pri-
marily. use. adsorptive,. precipitative,. oxidative,. and. biological. processes,.
to. remove. mostly. natural. organic. materials.. POPs. and. CECs. are. a. diverse.
group.of.compounds.that.include.PhACs,.PCPs,.hormones,.pesticides,.and.
industrial. and. household. chemicals.. There. are. growing. concerns. about.
these. compounds. because. of. the. detrimental. effects. associated. with. their.
use,. and. some. of. them. may. have. an. adverse. impact. on. the. development.
and.reproduction.of.ish.and.amphibians..Other.evidences.show.that.mam-
mals.could.be.sensitive.to.extremely.low.concentrations.of.POPS.and.CECs.
(AWWARF. 2007).. POPS. and. CECs. have. evolved. into. popular. concerns.
because.of.heightened.public.perception.and.increasing.attention.from.the.
scientiic.and.environmental.communities..However,.it.is.dificult.to.estab-
lish.irm.evidence.for.the.association.between.adverse.human.health.effects.
and.low-dose.exposure.to.POPs.and.CECs.
The.most.cost-effective.option.for.moderate.POPs.and.CECs.removal.treat-
ment.technologies.is.GAC.for.waste-.and.ground-water.treatment..Ozonation.
is. another. cost-effective. option. in. achieving. eficient. removal. of. POPs. and.
CECs..Sparingly.soluble.salts.such.as.silica.limit.the.reverse.osmosis.recov-
ery.to.around.35%,.which.is.necessary.to.pretreatment.in.softening.process.
to. increase. water. recovery.. Despite. the. high. cost,. precipitative. softening.
reverse.osmosis.(PSRO).is.the.only.technology.that.removes.not.only.POPS.
and.CECs.but.also.TDS.
POPs.and.CECs.are.a.collective.group.of.diverse.compounds.whose.physical.
and.chemical.characteristics.vary.broadly.even.within.the.same.subcategory..
About. 87,000. emerging. compounds. have. been. identiied. as. possible. EDCs.
(U.S..EPA.2008)..At.present,.no.single.technology.is.available.to.treat.all.POPs.
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