Seth Scott, Project Manager for Sustainability at the Infrastructure Sustainability Council, recently engaged in a thought-provoking conversation with Harmaan Madon. Their discussion explored what sets Alimentary Systems Limited (ASL) apart in sustainable waste management and bioenergy innovation.
Seth Scott:
Can you explain your project? It sounds like a bioenergy initiative using waste to generate methane. What exactly are you working on?
Harmaan Madon:
We use anaerobic digestion, which produces methane. However, we go beyond traditional systems by recovering nutrients to replace synthetic fertilisers and generating carbon credits. Our technology is about creating a circular system that integrates these elements.
Seth Scott:
I visited a bioenergy plant in Sydney. They produce biogas for the gas network and focus on fertiliser production. How does ASL differ?
Harmaan Madon:
That’s a good point. Many existing systems focus on single waste streams, such as wastewater or sludge. We are unique because we process mixed waste streams, including sewage sludge and food organics. Our technology achieves zero liquid discharge, meaning no effluent enters natural water systems. Additionally, we maximise gas yield to decarbonise wastewater treatment while producing a nutrient-rich fertiliser for agriculture.
Seth Scott:
How are you managing sludge? Current practices often leave sludge in geo-bags or send it to landfills.
Harmaan Madon:
You're right—sludge management is a challenge. Many facilities rely on outdated methods like geo-bags, where sludge is left to dewater over time. Our process uses thermal hydrolysis, which sterilises the sludge and transforms it into a high-value bio-solid compliant with global standards, ready for agricultural use.
Seth Scott:
How do you address concerns about contaminants like PFAs or pharmaceuticals in the waste stream?
Harmaan Madon:
Thermal hydrolysis breaks down pharmaceuticals, including synthetic hormones, significantly reducing their impact. No technology can fully eliminate PFAs and microplastics yet. However, we ensure their levels remain below health-based guidelines. Our focus is on reducing risk while promoting sustainable practices.
Seth Scott:
New Zealand doesn’t have a bio-solids land application standard. How do you navigate this regulatory gap?
Harmaan Madon:
It’s a challenge. We’ve engineered our process to meet US EPA Class A and UK PAS 110 standards, which are among the most stringent globally. By demonstrating compliance, we aim to establish similar standards in New Zealand, ensuring treated biosolids are safe for agricultural use.
Seth Scott:
Where is your project currently? Are you still in the R&D phase?
Harmaan Madon:
No, we’ve moved beyond R&D. We’ve developed the technology at lab and pilot scales and are now scaling up to a commercial plant in Nelson. This facility will process 10 tonnes daily, approximately 3% of Nelson’s sewage in our commercial technology demonstration.
Seth Scott:
What’s different about ASL’s approach compared to linear systems like Sydney’s wastewater treatment?
Harmaan Madon:
Our system integrates multiple waste streams, maximising energy and nutrient recovery. Linear systems focus on solving individual problems, like diverting waste from landfills. We collapse the linear model into a circular system where waste becomes a resource, creating perpetual energy and nutrient cycles.
Seth Scott:
How do you plan to engage with stakeholders like councils and farmers?
Harmaan Madon:
We’ve built strong relationships with councils, iwi, and industry partners. For example, we’re working with the regional sewage business unit and Waste Management NZ in Nelson. Our fertiliser is designed to undercut synthetic fertilisers by a third, making it attractive for farmers while supporting sustainability goals.
Seth Scott:
What are the main challenges you face in scaling this technology?
Harmaan Madon:
The biggest challenge is changing the status quo. Investors often dismiss anaerobic digestion as old technology without understanding our innovations. Additionally, councils operate in silos, separating waste streams instead of adopting circular systems. Educating stakeholders and aligning policies with circular economy principles is critical.
Seth Scott:
What’s next for ASL?
Harmaan Madon:
Our immediate goal is to complete the Nelson plant and prove the technology at scale. Beyond that, we aim to develop a carbon trading platform integrated with our hardware. This will fund the expansion of organic waste processing facilities across New Zealand, making zero-waste, zero-emissions systems the norm.