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Innovation Design Engineering (MA/MSc)

Felix Chen

Felix Chen is a product designer and social innovator working across disciplines. His projects focus on coffee innovation, generative design, and social issues such as surveillance and discrimination. As part of his final year project, he wishes to make a significant contribution to the coffee industry.

A portrait of Felix Chen

Why Coffee?

I have a long relationship with coffee, from something like a hobby to something I wish I could create or contribute to this industry. Before the life of IDE, I tried to use generative design to reinterpret a lever espresso machine. During the course, I drafted my critical and historical study thesis for The innovation for home coffee brewing: A balance between speciality and sustainability, I studied the history of coffee and the future environmental impact on coffee. Currently, I am working on a water treatment project for small coffee farms in Colombia with the aim of assisting these farms in becoming environmentally and economically sustainable.

RCA Showcase

I am proud to show a selection of the projects which I've worked on in the past two years.

Coffee cherry washing and sorting, Finca Patio Bonito
Depulping, Finca Patio Bonito

Coffee pollution

Coffee pollution is an underrated problem within the coffee industry and occurs during the washing process at coffee plantations. And the most two important factors is water consumption and contamination.

Water consumption / Some wet-milling processes use up to 1200 litres of water or more for each hundred-weight bag of coffee cherry, which may produce as little as 8 kg of export-ready green coffee.

Contamination / The wastewater or honey water is one of the leading contaminants in local water sources as it lowers pH levels and creates an anaerobic environment to kill life. The mucilage is loaded with sugars and pectin which will be fermented into acetic acid when released into local waterways. In addition, coffee cascara, or pulp, accounts for 2/3 of the weight of the whole coffee cherry. The most common way to treat the pulp is compost. However, some farms also discard it directly near the field, but it contains caffeine and alkaloid-rich leachate which is bad for the soil.

Water treatment with blockage problem
La Alejandria, Caldono, Cauca
Interview with Rodelfi Betancurt, El Mirador, Caldono, Cauca

The problems of existing solution

Technology & Maintenance / Lack of maintenance is the most common issue with the existing solution, the SMTA system. This may result in an over flow, blockage and a low removal rate. The lack of knowledge and feedback from the system provider may also result in frustration among coffee producers

Economic / Most farms in Cauca don’t use any water treatment due to the cost compared their farm size and production. Moreover, electricity and water supplies are unstable.

System Map

System map

This is a system can compost the coffee cascara and purify the coffee fermentation wastewater at the same time. Using the solar panel to power the spray system. Due to its modular design, the system can be expanded in the future.

Prototype in Colombia

The prototype in Pescador, Colombia

The very first vermifiltration system for coffee waste waste was build at Finca Patio Bonito, Pescador, Cauca, Colombia. This system is a practice for Lombriz Nadando to test in an actual context by sourcing the majority of materials locally and validating the design by using honey water and compost fresh coffee cascara.

The prototype was built on the hillside next to the washing space so it can use the gravity to let the waste water to run through the pipe and filter tanks and finally the water can be absorb by soil tank or be used for irrigation. There are still some problems to be solved in the future, such as monitoring the load rate over a long period of time and finding the optimal variety of earthworms.


Design for small coffee farms

In Colombia, Cauca Department, famous for specialty washed coffee, 99.4% coffee farms can be considerate as small farm, they worked individually, and most producers own roughly only one hectare of coffee.

The map of Finca Patio Bonit

Finca Patio Bonito

My project got massive support from Finca Patio Bonito, by processing the research and piloting the first prototype in Pescador, Colombia.

Worm dynamics experiment
Worm will move to the chamber with more organic compounds.
Comparison experiment
Comparison experiment


A series of experiments were conducted to validate the worm dynamics and tolerance to honey water and cascara. In addition, a comparison experiment showed that vermifiltration was superior in digesting and purifying water as compared to that without worms, demonstrating a rise in pH, a decrease in °Brix, as well as a better ability to transmit water.

What is vermifiltration? / Vermifiltration is a biological treatment process during which earthworms and microorganisms reduce the organic compounds inside the waste water.

Prototype in London
Prototype in LondonThis is a small-scale but fully functional prototype that utilises a 10 gallon tank rather than a 1 m3 tank.
Colombia prototype building process
Bill of materials
Bill of materials
Test Kit
Picture with Paola's family

Thanks to

Paola Trujillo and her family, Finca Patio Bonito, Coffee Producer in Cauca, Colombia

Prof. Michael Templeton, Civil and Environmental Engineering, Imperial College

Dr Laure Sioné, Civil and Environmental Engineering, Imperial College

Elsa Germain, Civil and Environmental Engineering, Imperial College 

Nestor Campo, Member of CAFICAUCA, Colombia

Lucia Solis, Coffee processing expert

CATA Export, Green coffee export / dealer

Jon Townsend, AST & Adviser


Alma Castro, Finca La Sierra, Cajibío, Cauca / Olga Lopez, La Alejandria, Caldono, Cauca / Hugo Trujillo, Las Orquídeas, Caldono, Cauca / Rodelfi Betancurt, El Mirador, Caldono, Cauca / Camila & Blanca Trujillo, Finca La Colina, Caldono, Cauca / Merly Joyas, Los Pinos, El Tambo, Cauca / Richard Velasco, El Porvenir, El Tambo, Cauca

Launch Project
F-Stool / Superform
transparency bin
Launch Project
Transparency Bin / Solo X
IRIS BOT / GIZMO (Work with Clément N. Bolle)