Advanced

Application of chemical oxidation processes for the removal of pharmaceuticals in biologically treated wastewater

Hey, Gerly LU (2013)
Abstract (Swedish)
Popular Abstract in Swedish

Den största källan till läkemedelsrester i vattenmiljön är utgående renat avloppsvatten från våra kommunala reningsverk. Läkemedel är utvecklade för att ha olika typer av biologiska effekter. Vilka dessa är i människan är relativt välkänt, medan effekterna på vattenlevande organismer och andra djur till stor del är okända. Detta i kombination med deras resistens mot de kemiska och biologiska nedbrytningsprocesser som pågår i reningsverken gör att de utgör en potentiell risk för miljön eftersom de inte avlägsnas i reningsverken utan följer med utgående vatten till miljön.

I denna avhandling undersöks om läkemedelsrester som finns i renat avloppsvatten från olika typer av... (More)
Popular Abstract in Swedish

Den största källan till läkemedelsrester i vattenmiljön är utgående renat avloppsvatten från våra kommunala reningsverk. Läkemedel är utvecklade för att ha olika typer av biologiska effekter. Vilka dessa är i människan är relativt välkänt, medan effekterna på vattenlevande organismer och andra djur till stor del är okända. Detta i kombination med deras resistens mot de kemiska och biologiska nedbrytningsprocesser som pågår i reningsverken gör att de utgör en potentiell risk för miljön eftersom de inte avlägsnas i reningsverken utan följer med utgående vatten till miljön.

I denna avhandling undersöks om läkemedelsrester som finns i renat avloppsvatten från olika typer av avloppsreningsverk i Sverige kan avlägsnas med hjälp av några olika kemiska oxidationsmedel. De som ingick i studien var klordioxid, perättiksyra och ozon. Den senare enskilt och i kombination med väteperoxid. Bland de undersökta läkemedelsresterna ingick antiinflammatoriska, analgetiska, antiepileptiska och antidepressiva preparat, hormonstyrande substanser och betablockerare. Reningseffektiviteten kvantifierades genom hur mycket av läkemedlen som kunde nedbrytas vid en viss dos, definierat som att hur mycket av ursprungssubstansen som försvann. Ska dock noteras att detta inte säger något om hur långt nedbrytningen går, dvs om endast en del av molekylen förändras eller om omvandling sker ända ned till koldioxid och vatten.

Resultaten av experimenten, som genomfördes som batch experiment i laboratoriet, visade att användning av ozon är det mest effektiva sättet att genom kemisk oxidation bryta ned (>90%) de flesta av de studerade läkemedelsresterna i utgående avloppsvatten. För att uppnå >90% reduktion krävdes en ozon dos på 5 - 10 mg/L. Där dosen både var beroende av vilken substans som studerades och vilken kvalitet som vattnet hade (primärt innehåll av organiskt kol (DOC) och graden av aromatisitet hos detta). Det kunde inte fastställas att en ökad effektivitet kan uppnås genom tillsättning av små mängder väteperoxid tillsammans med ozon. Däremot visades dessa experiment att en sådan tillsättning innebar en ökad reaktionshastighet vilket i sin tur innebär minskad behandlingstid och därmed också minskad volym av reaktionsbehållaren. Något som kan ha stor betydelse vid implementering av tekniken i praktiken.

Användning av klordioxid kan jämföras med ozon då båda reagerar med elektronrika funktionella fenol- och amino grupper. Emellertid visade experimenten att för vissa av de studerade läkemedelsresterna att reaktionen med klordioxid är långsammare än motsvarande reaktion med ozon. Detta betyder att potentialen för användning av klordioxid som behandlingsmetod kommer att bero på vilka läkemedelrester som är i fokus och på om det kan vara fördelaktigt ut andra aspekter. Här kan nämnas att klordioxidtekniken skulle kunna vara fördelaktig för småskaliga avloppsreningsverk eller vid reningsverk där behandling endast krävs under en begränsad tid. Anledningen är att anläggningarna för klordioxid är enklare och billigare att bygga både med avseende på klordioxidgeneratorn som reaktionskammaren, jämfört med motsvarande anläggningar för ozonbehandling. (Less)
Abstract
The discharge of effluents from wastewater treatment plants (WWTPs) is

considered to be the major source of residual pharmaceuticals frequently found in aquatic environments. The complex nature of such compounds tends to make conventional biological treatments aimed at their removal ineffective. The present thesis concerns the removal of 62 different active pharmaceutical ingredients commonly detected in Swedish wastewater effluents by means of chemical oxidation techniques. Techniques with potential to be effective are in particular peracetic acid (PAA), chlorine dioxide (ClO2), ozone (O3) and a combination of ozone and hydrogen peroxide (O3/H2O2), which all were included in this study. The performance of a given treatment was... (More)
The discharge of effluents from wastewater treatment plants (WWTPs) is

considered to be the major source of residual pharmaceuticals frequently found in aquatic environments. The complex nature of such compounds tends to make conventional biological treatments aimed at their removal ineffective. The present thesis concerns the removal of 62 different active pharmaceutical ingredients commonly detected in Swedish wastewater effluents by means of chemical oxidation techniques. Techniques with potential to be effective are in particular peracetic acid (PAA), chlorine dioxide (ClO2), ozone (O3) and a combination of ozone and hydrogen peroxide (O3/H2O2), which all were included in this study. The performance of a given treatment was evaluated in terms of the degree of pharmaceutical removal achieved and the oxidant demand of the wastewater. The effects of the characteristics of the wastewater have on the degree of removal

efficiency of different pharmaceuticals were also evaluated.

Ozone is considered to be the most efficient chemical oxidant for reducing the concentrations of a large number of different pharmaceuticals, the ozone dose required for this being fairly low (5-10 mg/L), depending upon the characteristics of the effluent. Over 90% of the pharmaceuticals investigated in most of the effluents could be eliminated to 90-100% by use of ozone, while several of the

pharmaceuticals being observed to be recalcitrant to chlorine dioxide treatment. The addition of small amounts of hydrogen peroxide during wastewater ozonation, although not enhancing the removal of pharmaceuticals, was found to increase ozone decomposition, presumably resulting in the formation of hydroxyl (OH)

radicals as secondary oxidants. The addition of small amounts of H2O2 in this way is seen as being advantageous in terms of its reducing both the treatment time and the reaction tank volume which is needed.

Of the various water quality parameters investigated, the organic carbon content was found to have a particularly strong effect on the removal of pharmaceuticals, due to its competitive behavior towards the oxidant. PAA appears to have the lowest degree of pharmaceutical removal, making it not a suitable treatment option for removing pharmaceuticals in the effluents. Although chlorine dioxide and

ozone appeared quite similar in their manner of removing pharmaceuticals, both of them reacting with electron-rich functional groups such as those of the phenolic and amino type, some of the pharmaceuticals reacted more slowly with chlorine dioxide than with ozone, given the same reactive substituent and structural

similarities. Thus, a decision regarding the possible use of chlorine dioxide for tertiary treatment should take account of how strongly the pollutant or pollutants in question are affected by it. The use of chlorine dioxide appeared to be particularly beneficial when a small-scale WWTP is involved or when treatment is required for only a limited period of time. Although ClO2 is slightly more expensive to produce than ozone, the preparation system and the reaction chamber

for treatment that are required are far simpler and less expensive to build than those needed for ozone treatment. It was noted that energy costs connected with ozonation are a function both of the ozone demand of the wastewater and the contaminant or contaminants to be removed. It appeared that, in view of the high degree of reactivity of ozone to a broad range of the pharmaceuticals that were

investigated, ozonation of secondary effluent is the most suitable alternative for most WWTPs. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Pons, Marie-Noelle, Universite de Lorraine-France
organization
publishing date
type
Thesis
publication status
published
subject
defense location
Lecture hall K:G, Center for Chemistry and Chemical Engineering, Getingevägen 60, Lund University, Faculty of Engineering
defense date
2013-02-21 10:15
ISBN
978-91-7473-453-9
language
English
LU publication?
yes
id
504571f5-d98b-4f42-80eb-4c505faa0932 (old id 3412268)
date added to LUP
2013-01-30 13:19:34
date last changed
2016-09-19 08:45:17
@misc{504571f5-d98b-4f42-80eb-4c505faa0932,
  abstract     = {The discharge of effluents from wastewater treatment plants (WWTPs) is<br/><br>
considered to be the major source of residual pharmaceuticals frequently found in aquatic environments. The complex nature of such compounds tends to make conventional biological treatments aimed at their removal ineffective. The present thesis concerns the removal of 62 different active pharmaceutical ingredients commonly detected in Swedish wastewater effluents by means of chemical oxidation techniques. Techniques with potential to be effective are in particular peracetic acid (PAA), chlorine dioxide (ClO2), ozone (O3) and a combination of ozone and hydrogen peroxide (O3/H2O2), which all were included in this study. The performance of a given treatment was evaluated in terms of the degree of pharmaceutical removal achieved and the oxidant demand of the wastewater. The effects of the characteristics of the wastewater have on the degree of removal<br/><br>
efficiency of different pharmaceuticals were also evaluated.<br/><br>
Ozone is considered to be the most efficient chemical oxidant for reducing the concentrations of a large number of different pharmaceuticals, the ozone dose required for this being fairly low (5-10 mg/L), depending upon the characteristics of the effluent. Over 90% of the pharmaceuticals investigated in most of the effluents could be eliminated to 90-100% by use of ozone, while several of the<br/><br>
pharmaceuticals being observed to be recalcitrant to chlorine dioxide treatment. The addition of small amounts of hydrogen peroxide during wastewater ozonation, although not enhancing the removal of pharmaceuticals, was found to increase ozone decomposition, presumably resulting in the formation of hydroxyl (OH)<br/><br>
radicals as secondary oxidants. The addition of small amounts of H2O2 in this way is seen as being advantageous in terms of its reducing both the treatment time and the reaction tank volume which is needed.<br/><br>
Of the various water quality parameters investigated, the organic carbon content was found to have a particularly strong effect on the removal of pharmaceuticals, due to its competitive behavior towards the oxidant. PAA appears to have the lowest degree of pharmaceutical removal, making it not a suitable treatment option for removing pharmaceuticals in the effluents. Although chlorine dioxide and<br/><br>
ozone appeared quite similar in their manner of removing pharmaceuticals, both of them reacting with electron-rich functional groups such as those of the phenolic and amino type, some of the pharmaceuticals reacted more slowly with chlorine dioxide than with ozone, given the same reactive substituent and structural<br/><br>
similarities. Thus, a decision regarding the possible use of chlorine dioxide for tertiary treatment should take account of how strongly the pollutant or pollutants in question are affected by it. The use of chlorine dioxide appeared to be particularly beneficial when a small-scale WWTP is involved or when treatment is required for only a limited period of time. Although ClO2 is slightly more expensive to produce than ozone, the preparation system and the reaction chamber<br/><br>
for treatment that are required are far simpler and less expensive to build than those needed for ozone treatment. It was noted that energy costs connected with ozonation are a function both of the ozone demand of the wastewater and the contaminant or contaminants to be removed. It appeared that, in view of the high degree of reactivity of ozone to a broad range of the pharmaceuticals that were<br/><br>
investigated, ozonation of secondary effluent is the most suitable alternative for most WWTPs.},
  author       = {Hey, Gerly},
  isbn         = {978-91-7473-453-9},
  language     = {eng},
  title        = {Application of chemical oxidation processes for the removal of pharmaceuticals in biologically treated wastewater},
  year         = {2013},
}