Denise E. Mall
Managing Director at EnsO Earth
Managing Director of EnsO Earth, the South African nonprofit teaching Net Positive Water, designing water systems that recycle more than they consume, the way nature wastes nothing.
Compiled by Antoine Walter - from insight gathered on and off his (don't) Waste Water microphone!
Denise E. Mall is a South African civil engineer and the Managing Director of EnsO Earth, a regenerative-infrastructure nonprofit she runs around one idea borrowed from nature: Net Positive Water, where a building recycles more water than it consumes. After 35 years in conventional engineering, she pivoted the whole of it toward biomimicry. As of 2026, she has shared that pivot once on the show.
Denise E. Mall did not choose engineering, engineering chose her. In mid-1980s South Africa, in her final year of high school, a company came looking for “a young girl to train in drafting,” and she took the job without ever realizing drafting was a path into engineering rather than the architecture she had imagined. There was no Google to check. She landed in water resources, took to it (her words) “like a duck to water,” and within six months the company was sponsoring her to study. She later learned she was apparently the first woman that firm had ever bursaried for engineering, which is why they put her through two days of psychometric testing and asked what would happen “if I become a mother.” She just wanted the job. Thirty-five years later, she is still in water.
Denise Mall’s turn came around 2008, after she had moved from Johannesburg to the Western Cape and was, in her telling, “trying to figure out life.” The Cambridge Institute of Sustainability brought Janine Benyus, the woman who coined the word biomimicry, to present live in Cape Town, and Denise walked out of that room asking herself “how did we get this so wrong?” Biomimicry is simply the practice of learning from nature instead of just about it, and Benyus frames it on three levels: nature’s forms (its shapes), its recipes (its chemistry and processes), and its systems. From there Denise pivoted her own engineering firm out of industrial and mining work and into green projects, and in 2018 she co-founded the Biomimicry for Africa Foundation, before that work grew into EnsO Earth.
Denise Mall’s signature idea is what she calls Net Positive Water, and the cleanest way to picture it is as a greater-than sign. The industry’s “net zero water” is an equals sign, where the water you reclaim matches the water you consume, roughly half and half. Net positive pushes past that: you recycle more than you take in. The trick that makes it possible is “water fit for purpose,” because only about 30 to 40% of the water a city sells you is true drinking-grade demand (drinking, cooking, washing), and yet we buy potable water just to flush a toilet, contaminate it instantly, and then pay the municipality to clean it back up so we can do it again. Denise calls that double-dipping “insanity,” and once you see it, you have, in her words, “realized Net Positive Water.”
Denise Mall’s hardware for that idea is what she calls a Living Machine, a wastewater train that uses living systems instead of brute chemistry, moving water through anaerobic, aerobic, filtration and polishing stages. The biodigester at its heart mimics a cow’s four-chambered stomach, and the methane it gives off is harvested for energy rather than vented. That captures her governing belief, which is that there is no such thing as waste in nature, only “valuable building blocks.” It is the same logic that drives newer onsite-reuse companies turning a building’s own wastewater into a resource, the kind of work Aaron Tartakovsky talks about on the show, and it sits at the heart of the nature-based and ecological-engineering shift you can hear running through the (don’t) Waste Water archive.
What makes Denise Mall worth listening to is that none of this is abstract for her. She frames the whole second act of her career as a moral choice, not a technical one, telling me she realized that staying on her old path meant “basically signing the life sentence or the death sentence of my future offspring.” The thing she is actually optimizing for is whether her great-grandchildren will have a planet to live on, and she reaches that through a simple loop she keeps coming back to: clean air, clean water and food are the three things you cannot live without, water drives all three (it grows the food, the food feeds the vegetation, the vegetation makes the air), and so water is the lever. You need eight minutes of air, three days of water, and forty days of food, and once you sit with those numbers, the urgency stops being a slogan.
“Waste does not exist in nature. There is no thing called waste in nature. Everything is a valuable building block, natural resource.”
Denise Mall is the rare engineer who spent a full career building the conventional system, decided it was pointed “180 degrees in the wrong direction,” and then set about teaching the next generation to build it the way nature would.
On (don’t) Waste Water
The time Denise Mall was a guest on the show:
The company
Frequently asked
- Who is Denise Mall?
- Denise E. Mall is a South African civil engineer and the Managing Director of EnsO Earth, a regenerative-infrastructure nonprofit. After 35 years in conventional engineering, she pivoted toward biomimicry and now champions Net Positive Water, the idea of designing water systems that recycle more water than they consume.
- What is EnsO Earth?
- EnsO Earth is a South African nonprofit (a registered Public Benefit Organization) that works at the intersection of biomimicry, circularity and ecological design to push infrastructure beyond sustainable toward regenerative. Led by Denise Mall, it runs real projects and trains practitioners across water, waste, nature, energy and climate.
- What is Net Positive Water?
- Net Positive Water, the concept Denise Mall champions, means a building or site recycles more water than it consumes. Where net zero water balances reclaimed against consumed water at roughly fifty-fifty, net positive pushes past fifty percent, helped by matching water quality to its actual use instead of flushing toilets with drinking water.
- How did Denise Mall get into biomimicry?
- Denise Mall stumbled into engineering in 1980s South Africa, then spent decades in conventional infrastructure. Around 2008, a live talk in Cape Town by Janine Benyus, who coined the term biomimicry, changed her direction. She pivoted her firm toward green projects and co-founded the Biomimicry for Africa Foundation in 2018.
- Is Denise Mall the same as EnsO Earth?
- Denise Mall is the person; EnsO Earth is the nonprofit organization she leads as Managing Director. People often search the two together because her signature work, biomimicry and Net Positive Water, runs through EnsO Earth. She also previously founded the Biomimicry for Africa Foundation and ran the engineering firm Synura Projects.
- Where can I listen to Denise Mall?
- Denise Mall appeared once on the (don't) Waste Water podcast, in 2021, on the episode How Biomimicry Leverages the Best of 3.8 Million Years of R&D. You can listen, watch on YouTube, or read the write-up using the links above on this page.