Four scientific questions.

Hydrothermal processing has traditionally been studied as a route for converting wet biomass into biofuels. Yet real-world wastes — sewage sludge, livestock manure, food waste — behave very differently from model feedstocks. Their chemical complexity governs reaction pathways, product distribution, and ultimately the efficiency of resource recovery.

What we’ve shown

• How waste composition and reaction conditions govern the formation of bio-oil, hydrochar, and aqueous products.
• That hydrothermal processing and anaerobic digestion are complementary — together they recover more energy than either alone.
• That a single waste stream can yield multiple resources: up to 90% of the phosphorus in sewage sludge is retained in the hydrochar.

What we’re doing now

Predictive circular resource recovery — combining mechanistic experiments with techno-economic analysis and life-cycle assessment to find the operating conditions that maximize environmental, economic, and agronomic performance.

Who works on this

All papers on question I

Carbon-rich solids from thermochemical processing have traditionally been regarded as low-value fuels or soil amendments. We challenge this paradigm by treating biochar and hydrochar as engineered carbon materials whose structure and functionality can be tailored for environmental and industrial applications.

What we’ve shown

• Hydrothermal carbonization can retain nutrients in the carbon matrix while modifying its physicochemical properties.
• Phosphorus from sludge and digestate is preserved in plant-available forms, making hydrochar a multifunctional platform rather than a by-product.

What we’re doing now

Establishing structure–property relationships for the rational design of waste-derived carbons: activated hydrochar for pollutant adsorption, nutrient-enriched slow-release fertilizers, and conductive carbons for electrochemical applications — supported by a BARD project.

Who works on this

All papers on question II

Conventional recycling treats heterogeneous waste as a problem that requires extensive separation. We take the opposite approach: understanding and exploiting interactions among waste components to create new pathways for resource recovery and circular manufacturing.

What we’ve shown

• Subcritical water selectively depolymerizes condensation polymers such as PET and nylon-6 while preserving more stable polyolefins — enabling selective recovery from mixed plastic waste.
• Co-processing plastics with lignocellulosic biomass changes carbon partitioning, polymer transformation, and hydrochar formation — producing materials not achievable by processing each stream separately.

What we’re doing now

Engineering plastic–biomass interactions to produce biodegradable and functional carbon materials (supported by the Ministry of Science and Technology and the Technion Sustainability Frontier), and — within the national SIDE2DAIRY consortium — mild thermochemical fractionation of agricultural residues into fermentable sugars for sustainable protein production.

Who works on this

All papers on question III

Recovering resources is only one step toward a circular bioeconomy. Their successful reintegration into agricultural and natural ecosystems ultimately determines whether a recovery strategy is sustainable. We study how recovered products interact with soils, plants, microorganisms, and aquatic ecosystems.

What we’ve shown

• Maximizing nutrient recovery from anaerobic digestate must be balanced against impacts on soil salinity, structural stability, and greenhouse gas emissions.
• Resource recovery technologies must be evaluated within the environmental systems in which they operate.

What we’re doing now

Pilot-scale constructed wetlands for polishing agricultural digestate (EU PRIMA consortium), and high-throughput sequencing to link microbial community dynamics with treatment performance and system resilience.

Who works on this

All papers on question IV