Interaction Between Micropollutants and Degradative Biofilm Communities : Basis for a Biomimetic Approach to Water Treatment

Kenchenten, Kirsten (2017-03)

Thesis (MSc)--Stellenbosch University, 2017.

Thesis

ENGLISH ABSTRACT: The remediation and reclamation of water has become a critically important issue, as the use of water as a conduit of waste has resulted in the contamination of a resource that life on Earth cannot function without. Research has shown that pollutants at trace levels, or micropollutants, are not being removed adequately from treated water and, in some cases, the micropollutant concentrations actually increase following treatment. Microbial aggregates, such as biofilms, are important constituent in wastewater treatment, in both conventional wastewater treatment plants (WWTPs) and in new-generation alternatives such as biomimicrybased constructed wetlands. This project was conducted in the paradigm of biomimicry, the concept of using inspiration from nature to provide innovative solutions to anthropogenic problems. The aim of the study was two-fold; namely 1) to investigate the laboratory-based degradation of selected micropollutants by biofilms, with microbial activity as the key driver of biodegradation and, 2) to extrapolate these findings to gain understanding of the microbial processes responsible for the functioning of biomimicry-based water treatment systems. Of particular interest was the potential consequence of labile nutrient availability on the degradation of micropollutants in the treatment systems. The results showed that, while labile carbon sources (such as glucose) do affect the removal of the tested micropollutants, methylparaben and carbamazepine, the degree of this effect is not significant enough to explain the lack of micropollutant removal. In contrast, these two compounds had a significant effect on biofilm structure, even when applied at low concentrations (1000 ng.L-1 and 600 ng.L-1 for methylparaben and carbamazepine, respectively), as revealed by scanning confocal laser microscopy. Microbial biofilms execute degradative functions with flexibility and are furthermore able to efficiently adapt in a manner that humans have yet to replicate. Since our dependency on natural processes such as bio-utilisation and bio-assistance of microbes in our constructs cannot be denied or replaced, biomimicry shows promise as a framework for the design of wastewater treatment systems that replicate natural processes.

AFRIKAANSE OPSOMMING: Die remediëring en herwinning van water het 'n krities belangrike saak geword, as gevolg van water wat gebruik word as 'n watervoor vir afval. Dit het gelei na die besoedeling van ‘n hulpbron waarsonder lewe op aarde nie kan funksioneer nie. Navorsing het bewys dat besoedeling in baie klein hoeveelhede as ook mikrobesoedeling nie doeltreffend vanuit behandelde water verwyder word nie en in seker gevalle selfs verhoog word na behandeling van die water. Mikrobiese aggregate soos biofilms, is 'n belangrike bydrae tot afvalwater behandeling in beide tradisionele rioolsuiweringswerke asook in nuwe-generasie alternatiewe soos biomimiek-gebaseerde opgerigte vleilande. Hierdie projek was gedoen in die paradigma van biomimiek, die konsep om inspirasie vanuit die natuur te verkry om innoverende oplossings te vind vir antropogeniese probleme. Die doel van die studie was tweeledig; naamlik 1) om die laboratorium-gebaseerde degradasie van geselekteerde mikrobesoedeling te bestudeer deur die gebruik van biofilms met mikrobiese aktiwiteite as die sleutel dryfpunt van die biodegradasie, asook die ekstrapolering van hierdie bevindings om kennis te bekom van die mikrobiese proses wat verantwoordelik is vir die funksionering van biomimiek-gebaseerde waterbehandeling sisteme. Van spesifieke belang was die potensiële gevolg wat labiele voedingstof beskikbaarheid op die degradasie van mikrobesoedeling in behandeling sisteme het. Die resultate het gewys dat labiele koolstof bronne (bv. glukose) wel 'n bydrae lewer om die getoetsde mikrobesoedeling, methylparaben en carbamazepine, te verwyder, maar ook dat dit nie beduidend genoeg was om die tekort van mikrobesoedeling te verduidelik nie. In kontras het hierdie twee verbindings het 'n beduidende effek op biofilmstrukture gehad, selfs waneer dit in klein konsentrasies (1000 ng.L-1 en 600 ng.L-1 vir methylparaben en carbamazepine, onderskeidelik) toegedien was, soos bewys deur middel van 'n skandering konvokale laser mikroskopie. Mikrobiese biofilms voer degradering uit met buigsaamheid en is daardeur in staat om aan te pas in ‘n manier wat mensdom nog moet naboots. Omdat ons afhanklikheid op natuurlike prosesse soos biobenutting en bio-bystand nie ontken of vervang kan word nie, lyk biomimiek belowend as 'n raamwerk vir die ontwerp van afvalwaterbehandeling sisteme wat natuurlike prosesse naboots.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/100980
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