Enhancing micro-pollutants removal from hospital wastewater by biological design

Lead Research Organisation: University of Glasgow
Department Name: School of Engineering

Abstract

The release in natural waters of biologically active contaminants is a serious concern at a time when ever-increasing demand threatens water security. While many of these xenobiotic compounds have recognized ecotoxicological effects, there is a growing concern on their human toxicity too. Increasing ubiquity of micro-pollutants in natural waters opens the possibility of their presence in drinking water. Conventional drinking water treatments aim to remove pathogens, reduce turbidity and control odour and taste and the employed engineering processes reduce somewhat the load of micro-pollutants. Complete removal, however, involves high chemicals and energy demand technologies and therefore, in the current state of knowledge, theirpotential benefits are not worth the environmental expenditure.

Waste water from hospitals is likely to have high concentrations of pharmaceutical substances and their degradation products but does not undergo any further waste water treatment before reaching the sewage. This is of concern as some micro-pollutants are not removed by the traditional water treatment methods, and may affect drinking water we consume. Working alongside NHS Highlands, it is proposed to investigate the use of a biotechnological pre-treatment for hospital wastewater.
Treatment biotechnologies remove pathogens, nutrients and transition metals through a mixture of
physical and biological processes. For instance, ammonia oxidizing bacteria (AOB) and ammonia
oxidizing archea (AOA) carry out transformation of ammonia via their ammonia monooxygenase
(AMO) enzyme. Importantly, the AMO enzyme has broad substrate specificities and canalso oxidise
co-metabolically a wide range of contaminants. This property opens the possibility that the ammonia oxidising community of biological treatments can be optimisedto efficiently remove both nutrients and micro-pollutants. The aim of this project is to identify key nitrifying microbial communities and conditions to design an inncoulum for biological filters for untargeted biotransformation of contaminants alongside ammonia removal. Initial work will be to create microcosms from various environments including coastal and river sediments, nitrifying activated sludge and lab-scale biological filters under nitrifying conditions spiked with ammonia and environmentally relevant loads of micro-pollutants. Using novel analytical approaches, quantitative polymerase chain reaction and targeted gene high-throughput sequencing, the nitrifiers and their co-metabolic response to micropollutants present in hospital wastewater will be characterised. Based on these results, a nitrifying community with the capacity to also oxidise a broad range of micro-pollutants will be engineered. Through a new series of microcosms, further investigation into the removal rates of mixtures of contaminants at high concentrations by this seed community and their relationship to ammonia concentrations and other chemical parameters. Finally, quantitative structure-activity relationship modelling will be establish to predict degradation of untested pollutants and multiple regression analysis to recommend remedial approaches to failure (dosing of ammonia, change in pH...).

Publications

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Description Girls in Physics Event 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact I demonstrated at a University-held event titled 'Girls in Physics'; aimed at 3rd year high school females; to encourage them to take science options in their course choices. I demonstrated with the activity 'Calpol in the Environment' which demonstrates how pharmaceutical compounds are excreted from one's body and end up in the environment, the negative consequences this has, and how we can harbor microbes to degrade specific compounds. The event was ran with 9 groups of around 16 pupils, with interaction form the pupils a key aspect of the activity. The main take-home message from the activity was not to flush unused medication down the toilet, but to return it to a pharmacy. Some pupils showed an interest in the fate of the pharmaceuticals, engaging through questions and stories.
Year(s) Of Engagement Activity 2020
 
Description Glasgow Science Festival - Dippy About Nature 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Our stall was split into two tasks: Calpol, Microbes and Lego, and Biofilm for Babies. The first task was designed to teach children what happens to the pharmaceutical compound (paracetamol, known to children as Calpol) when ingested and excreted. A molecular structure of paracetamol (C9H8NO2, Calpol to the children) allowed them to count the number of carbon atoms; and figure out how many oxygen atoms were needed to form carbon dioxide (CO2). The molecule could then be broken down and reassembled to form the carbon dioxide. This worked well, particularly with older children as it allowed them visibly to see the breakdown of the paracetamol. A 'microbe' from the second task was then shown and the children were tasked with showing the exponential growth of the microbes using the Lego bricks. This allowed us to teach them how fast microbes grow.
The second task, 'Biofilm for Babies'; used hand-made microbes (made from resin and coloured Playdough in a plastic petri-dish) to show the formation of a biofilm. Children were tasked with the separation of the microbes into those which can breakdown Calpol, and those that cannot; following a guide on a poster. This task allowed us to teach the children that microbes can be used to break down pharmaceutical compounds; but only certain microbes degrade certain compounds.
Many children and adults were engaged with the task; with a number of parents concerned about disposing unused medication by flushing it. This gave us the opportunity to explain in further detail the consequences of this; and point them to the pharmacy for correct and safe disposal of their unused medication. Many requested further information on the topic, as they wanted to share the knowledge with other family members.
Year(s) Of Engagement Activity 2019