Production and Prototyping Equipment for Manufacturing Ceramic Media for Water Biofiltration

Posted on

Image: Research Associates Rosy Heywood and Sonny Lightfoot using the extruder

Written by Rosy Heywood, Research Associate, Centre for Print Research

The production and prototyping of ceramic media has been predominantly based at the Centre for Print Research labs. The centre has expansive facilities with an array of technical equipment. Specialist machinery used in this project includes a hydraulic piston extruder and 3D printer. Other workshop equipment was utilised including an industrial dough mixer, ball mill and laser cutter.

During the design phase of creating the ceramic media it was considered a requirement that the production methods are able to produce 160 pieces of each type of media efficiently and consistently in size and also, the production method should be scalable and easily repeatable for future experimentation.

In our research, the importance of the porosity of the ceramic media was being analysed. And three production methods were established for the creation of three sets of media of varying porosities. Low porosity media was produced through extruding standard terracotta clay, medium porosity was produced by extruding a clay and sawdust composite and high porosity media was produced using an organic foam impregnation method. The specialist technical equipment used for low and medium porosity media is detailed below.   

Extrusion

With its origins in the production of bricks, extruders are now used in many different industries. According to Frank Handle in Extrusion in Ceramics, notable applications are in the production of foodstuffs such as pasta, shaping of aluminium profiles, wrought copper alloys and steel and for the extrusion of hard metal, graphite, coal and plastics.

The extruder housed at The Centre for Print Research was built by the technical team for the specific use with clay and clay composites. The clay is pushed through a die by the manually operated hydraulic ram. The die determines the extruded profile shape and size which can be extruded to different lengths.

To create the desired extrusions, we designed dies and 3D printed them to fit the ram cylinder. The benefits of using a piston extruder for this research is; it is easy to clean so small chance of contamination, little material is wasted and bespoke extrusion profiles can be produced with ease and precision using desktop 3D printers.

3D Printing

3D printing technology was utilised in this research to create bespoke manufacturing tools. Additive manufacturing is the production of 3D objects printed from a CAD (Computer Aided Design) model.

Filament is fed through the printer and the model is printed layer by layer. In prototyping we used a recycled Polylactic Acid (PLA) filament for the tools. PLA is a bio-plastic made from fermented plant starch and is commonly used in 3D printing due to versatility and ease of printing.

The advantage of using this technology is that we could create bespoke tools for specific processes during manufacturing the media. For example, a die was printed to extrude cylinders 20mm in diameter and a cutting jig was printed to cut them into exactly 20mm individual lengths.

Figure 2 3D printer in action printing an extrusion die

Investigating The Unique Properties of Ugandan Barkcloth as a Potential Filtration Material for Cleaning Contaminated Waters

Posted on

Main image: Final barkcloth. Source National Geograpic.

Written by Rosy Heywood, Research Associate, Centre for Print Research

On the Healthy Waters project one of our key focusses has been creating highly porous ceramic pots for direct filtration in third world countries and low resource settings. I have recently been investigating a new material as either an alternative to ceramics or used in conjunction with it. The Ugandan barkcloth is made from bark of the native Mutuba tree (Ficus Natalensis). The bark regenerates itself for up to 100 years and the process of making it into useable cloth requires little resources and a moderate amount of labour compared to conventional cloth. No spinning of fibre, weaving of threads or dyeing of cloth is necessary. Although, sometimes the cloth is naturally dyed for aesthetic purposes. So, it is a very sustainable and renewable material.

Barkcloth making in Uganda is on the UNESCO Representative List of the Intangible Cultural Heritage of Humanity. The inner bark of the Mutuba tree (Ficus natalensis) is harvested in the wet season and beaten with wooden mallets until soft. The final cloth will be roughly 10 times its original size. Any tears are hand stitched and often fragments of cloth are stitched together to make larger pieces. The introduction of cotton has rendered barkcloth an endangered craft in Uganda. If using the cloth as a water filter proves successful, then it could give skilled jobs to local village people. The cloth is historically made by men but there is potential here to empower women by teaching them a new skill.

Simple cloth filters are used as a quick way to rid larger particles from contaminated waters. Studies have shown old worn sari cloth can reduce cholera incidence from water collected from ponds and rivers by half. (Huq et al, Colwell RR et al.)

The use of barkcloth from the Mutuba tree as a water filter has not yet been researched however there is some research of the properties of barkcloth for medical purposes and as a fashion textile. New research from science and textile researchers published in the Journal of Applied Microbiology examined the feasibility of using bark cloth as an antimicrobial fabric within wound care management. It found that Ugandan bark cloth could stop the growth of MRSA by more than 99 per cent. Researchers from Istituto Marangoni London and Manchester Metropolitan University have collaborated with artists, environmentalists, farmers and fashion design practitioners across the world to discover the potential applications of barkcloth including how it could be used as a responsible material in luxury fashion.

I have carried out an initial porosity test by folding the cloth twice and wrapping it over a bucket. Water was then poured through a perforated cup on top of the cloth. The cloth showed resistance to water initially and then slowly water was able to flow through. The filtered water had a slightly orange tinge and contained a small amount of bark fibres. I tried pre-soaking the barkcloth however the soaked water changed colour to an orange/red hue.

This proved more testing is required for better quality outputs. This line of experimental research is at a very early stage and further inquiry is required to find out if barkcloth is a suitable material for filtering water. Including a toxicity report of the barkcloth soaked water, flow rate analysis and testing it in conjunction with ceramic filter discs.

Meet the team: Rosy Heywood

Posted on

Rosy Heywood is a Research Associate at The Centre for Print Research (CFPR) at UWE. In this interview, she discusses her work as a sustainable textiles designer & researcher, and her role in the Healthy Waters research cluster.

Could you tell us a bit about your background and how you came to work in your current area?

I studied a MA in Design at UWE, during the pandemic. I started in 2019 and graduated last year, and my tutor, Dr Laura Morgan, was working at CFPR – the Centre For Print Research – which is the department that I’m working in now. She hired me as a Research Associate on a natural dyeing and laser engraved biomaterials project because my MA project was very relevant, I had focused on textiles and sustainable materials and specifically natural dyeing. So, when this project came along with Healthy Waters, it overlapped with the natural dyeing work that I did; you can’t get away from the amount of water and the toxicity of water that synthetic dyes use, so sustainable water management was an area that I was already very interested in.

So, about a month after the project with natural dyes finished, Tavs [Dr Tavs Jorgensen, Associate Professor and AHRC/RCUK Innovation Fellow] got in contact with me about the Healthy Waters project. And I thought, ‘Wow, this sounds exciting’. Ceramics is a slightly new area for me – I did do some on my Master’s, because when you first start you have to do a lot of different workshops in different areas of design – but it’s been really great to be picking up a new skill and starting to become a bit more of an expert in it. Sonny [Sonny Lee Lightfoot, Research Assistant and Product Design Technician] and Tavs have been brilliant, I’ve been able to pick up lots of skills in ceramics. For me, I’ve come into this with my design training and my design thinking, and it’s been amazing to apply that in a new, fresh area.

It’s been really interesting to hear how the arts and science departments have been collaborating on this project. What’s the experience been like for you, leaning further towards the technical scientific elements of the project?

Sadie, a MSc student who has been using our ceramic beads to test for biological filtration, produced a chart of how well our ceramic media did during filtration and it was great to see the results from our combined work; it’s made me really interested in how I can ‘science-ify’ my research and improve that aspect of it. I’m looking into doing a PhD and I’d like to move towards a material science or textile science direction – that’s something which is happening in the CFPR anyway, we have the graphene lab and the researchers based there have great expertise in material sciences.

Sometimes when you’re creative, you get so embedded in the design or art of something, it’s easy to forget other aspects. So when you’re able to merge it with science, it opens up a new way of thinking around design – going forward, this project is definitely going to change the way I think about designing.

You mentioned earlier that you did your masters throughout COVID lockdowns – what was that experience like for you?

It was difficult because it’s a very practical course. A lot of it was things we’d have to be on campus for, to use the workshops. Initially I was doing a lot of digital embroidery, for example, and that had to be done on campus – I can’t just buy a digital embroidery machine at home! So that definitely changed my path into a different area for my Master’s; I came into it thinking I was going to be doing digital embroidery and art installations, which became increasingly more difficult. So, I chose to do something I could do from home: natural dyeing. My work organically grew into more of a research project. Dyeing was something I could do at home and I was really interested in learning more and experimenting with it. I think in a way COVID kind of made me realise a different path that I wasn’t expecting to go on and brought me to where I am now – even though it was a very difficult time to be stuck at home, it forced me to think a lot more about what exactly I enjoyed doing and what I am good at.

It sounds like the new route you’ve been taken down is pretty great – the Healthy Waters project seems to have a lot of potential to make a big difference in the world!

Definitely. At the beginning of my Master’s, I hadn’t thought much about the importance of the work I was creating. I was only thinking, ‘What do I want to create’ rather than considering the bigger picture. But in research, you have to think about an important question that you want to solve and the solutions often involve other people and everything going on around you; I found my focus in sustainability because it’s so important today. What we’re doing now on the Healthy Waters project is creating a very sustainable method of cleaning water and my work with the CFPR is creating ceramic vessels and media for biological filtration.

Your MA focused on sustainable design as well, do you think you’ve always had that drive to protect the environment or has that grown as you’ve encountered a more scientific angle to work?

It’s hard to avoid it – you see so many statistics, and real-life instances, like this heatwave we’re having, and you see the need for sustainable solutions and change all around you. I think before my MA I hadn’t really thought that I could merge that into my design practice but in the project that I did, about natural dyeing, I started trying to create a more circular method of production. I worked on techniques to use plants to dye biodegradable materials. In essence, they could be buried back into the soil to break down, and the dyes could be naturally disposed of since they’re plant-based and non-toxic to the environment – it’s essentially diluted plant waste returning its nutrients to the ground. That research flowed really nicely into what I’m doing now, creating clean water. It’s been fascinating to hear how they test the water, what they find in the water, and how to deal with it – especially biological filtration, which I didn’t know much about as a method of cleaning water before I joined this project.

One of the Healthy Waters project’s aims is to support low-middle income countries with the technology you’re developing – does that add an extra source of motivation for you?

Definitely. It’s those things that are the most motivating in your work; that’s something that I’ve discovered recently in my professional experience as a researcher, but also in my MA: having motivation is so important in your work and working in such a crucial and important area only motivates me more. It’s inspiring, really.

[You can read more about the goals of the Healthy Waters project on their blog post here!]

You’ve mentioned you’d like to go on to do a PhD. What do you hope the future has in store for you in that regard?

That’s something that I’ve been trying to work out for myself because often to get further in academia, you need to do a PhD. I’m working with a few people at CFPR to figure out what I want to do, what I’d want my research question to be – what I’d want to discover, because a PhD is really all about learning and finding something that needs a solution created. It’ll definitely be in the sustainable materials or sustainable textiles range related to that circular economy I mentioned earlier. But the experience I’ve had now on Healthy Waters has been really great, getting to hear from scientists and work alongside them, to have that new experience for my PhD where I can relate scientific backing to my work. I haven’t got a solid answer but my goal is really to stay at the CFPR, to work on more research projects – there’s always more stuff coming up! I’d love to work with more people at UWE, there are so many people with so many different skills and areas of expertise, and I’d love to branch out and work with people from different departments.

You can connect with Rosy on her website and via her LinkedIn profile.

Testing Ceramic Methods for Producing Beads for Biofilm Water Treatment

Posted on

By Rosy Heywood, Research Associate at Centre for Print Research.

Main image: Fig 1: Boxes of organic foam impregnated ceramic beads and plain ceramic beads adjacent to a pot of traditional beads

In a previous blog post, by my colleague Sonny Lightfoot, we introduced the research being conducted into creating ceramic beads as a medium to grow biofilm within a water filter. We have now created 3 types of ceramic beads which have been tested for water filtration; organic foam impregnating method, clay and sawdust burn off method and plain ceramic. For each method we used the same terracotta clay, made the beads into 20mm pieces, and fired the beads at the same max kiln temperature of 1100˚.

Organic foam impregnating method

For this set of beads we laser cut compressed cellulose sponge into 20mm circles, expanded them in water and dipped them into clay slip. The beads were then left to dry and fired. During the firing process the sponge burns off leaving the porous structure behind. This method has been used to test beads with high porosity and high surface area creating lots of sites for the biofilm to grow onto.

Figure 2: Dipping laser cut sponges into terracotta clay slip

Sawdust and clay method

For this set of beads we mixed fine sawdust with clay at a 5:3 ratio. We are currently experimenting with the best ratio and method of mixing but to produce these beads we mixed by hand initially then used an electric mixer to fully combine the two components. We then extruded the clay using a hydraulic extruder into lengths and cut using a 3D printed jig into 20mm pieces. The beads were then left to dry and fired. During the firing process the sawdust burns off leaving a porous structure behind. This method has been used to test beads with high porosity.

Figure 3: Freshly extruded and cut sawdust and clay beads before firing

To produce the plain ceramic pieces we used the same method as above but without adding the sawdust. This method will test the effectiveness of the natural porosity of ceramic.

After firing we then tumbled the beads in a ball mill to smooth the edges. The beads were then dried in an oven and tested for effectiveness by MSc student Sadie Hadrill and PhD candidate Josh Steven in the science labs on Frenchay campus. Stayed tuned for another blog post coming soon where Sadie and Josh detail their process and results from the testing.  

Developing the methods and experimental work

Since creating these beads, the team and I in the CFPR labs have been experimenting with ways of combining sawdust with clay in large batches and the ratio of sawdust to clay. We have also been furthering our design research by modelling a coil pot from sawdust clay to test it’s suitability for pot making and experimenting with high surface area to low volume shapes using the organic foam impregnating method. These shapes could be tessellated or interlocked to create a unique structure for a vessel to naturally purify water using the biofilm method. The idea is to create a uniquely beautiful and practical container to filtrate water with the design inspired by natural biomorphic structures that can tesselate into user determined patterns and shapes. This experimental research is at its early stages and will slowly develop over the course of the project alongside our bead and porosity testing.

Figure 8: Organic foam impregnated ceramic tessellating shapes experiment

Initial Ceramic Research

Posted on

Written by Sonny Lightfoot, Research Associate and Technician at Centre For Print Research (CFPR)

In the latest issue of Craft Magazine they look at the work of Potters for Peace (PFP)  ‘a non-profit, social justice organization focused on using clay based solutions to address the problems of poverty.’ The amazing work PFP have implemented and published around locally made ceramic water filters has been a big inspiration for us here at UWE working on Heathy Waters. The literature produced by PFP has been a useful resource to start our own research especially around the use of burn-out material to be added to clay to increase precocity. Where PFP have developed a process where the ceramic filters are produced with a mould and a hydraulic press, we are looking at the already existing skills and process of local potter’s to hand building and pit fire water filter, like that of the craft potters in Kisoro Uganda, who currently produce ceramic cooking stoves.

Foam Impregnated Ceramic

Our initial ceramic tests have been focused on producing ceramic beads of different porosity to work as a medium for a biofilm to grow within a water filter. We have looked at two processes for these beads, extrusion, a well-established industrial process, and a organic foam impregnating method in which we laser cut compressed cellulose sponge that is then expanded in water then dipped in a ceramic slurry.

Extruded clay with added burn out material

Our next tests will be looking at producing a hand build ceramic water filter using a basic hand building technique known as coiling, which is more in line with the hand building process of the Ugandan potters. The pots will be made from terracotta clay with sawdust added in different percentages they will then be tested to establish the balance between increasing precocity to reduce time taken for the water to pass through the filter but still maintain a high efficacy of removing bacteria and pathogens.

Mixing clay and saw dust in preparation to coil build ceramic water filter

Back to top