Business model 4:
Carbon, nitrogen and phosphorus recovery at sewage treatment plants
Carbon-Nitrogen-Phosphorus Recovery Wastewater Treatment Process for Sewage Plants
Sewage treatment accounts for around 1% of global electricity consumption and emits some 257 Mt CO₂-equivalent a year. Scaling Bloomo up turns treatment cost into resource recovery and carbon fixation, across four layers: lower aeration, CO₂ fixation, nitrogen and phosphorus recovery, and N₂O suppression.
Context, product, outlook
Context
Sewage treatment accounts for around 1% of global electricity consumption and emits some 257 Mt CO₂-equivalent a year. Aeration alone consumes 50–60% of the total energy, and nitrogen removal generates N₂O, with a GWP of 273.
Product
Bloomo for Sewage fits into existing treatment processes. It integrates oxygen supply through photosynthesis, CO₂ fixation and the assimilation of NH₄⁺ into amino acids, targeting removal efficiencies of > 90% for nitrogen and > 90% for phosphorus.
Outlook
Rolled out through licensing to infrastructure companies and municipalities. We are working towards conformity with the EU Water Framework Directive, the creation of carbon credits, and an evolution into Water as a Service.
Users and product
USER
Municipalities and infrastructure companies
- High energy consumption in sewage treatment
- Requirements to quantify and suppress N₂O and CH₄ emissions
- Nitrogen and phosphorus resources discarded, with depletion risk
- Decarbonisation during the renewal of ageing plants
PRODUCT
Bloomo for Sewage
An integrated algal process that fits into existing plants
- Photosynthesis substituting for aeration energy
- Direct fixation of CO₂ from flue gas
- Nitrogen turned into a resource by assimilating NH₄⁺ into amino acids
- N₂O suppression through biochar addition
Core technology and features
Lower aeration energy
Oxygen supply through photosynthesis partly substituting for O₂ supply to aerobic bacteria
Direct CO₂ fixation
Takes in CO₂ from plant flue gas; 1 t of biomass ≈ 1.83 t CO₂ fixed
N and P recovery
NH₄⁺ assimilated into amino acids and protein. > 90% with PBR+MPBR
N₂O suppression
Biochar addition mitigates N₂O emissions from microbial denitrification
Turning sewage treatment from a cost into resource recovery and carbon fixation
Sewage treatment is indispensable infrastructure for public health, yet it accounts for around 1% of global electricity consumption[1] and emits some 257 Mt CO₂-equivalent of greenhouse gases a year[2]. Aeration alone consumes 50–60% of the total energy[3], and nitrogen removal generates N₂O (GWP 273)[4][5]. Scaling Bloomo up proposes a process design that turns this structure from treatment cost into resource recovery and carbon fixation.
PROBLEM Structural problems of conventional sewage treatment
High energy consumption and CO₂ emissions
Aeration takes 50–60% of the electricity consumed by the activated sludge process. The global sewage treatment sector accounts for around 1% of electricity consumption and is expected to grow 20% by 2030.
References: [3][6][7]
N₂O emissions
Incomplete nitrification and denitrification generate N₂O as a by-product — an extremely potent greenhouse gas with a 100-year GWP of 273, whose emission factor varies markedly between facilities.
References: [4][5][8]
Nitrogen and phosphorus resources discarded
Nitrification and denitrification release nitrogen to the atmosphere as N₂. Phosphorus is likewise not put to use during sludge disposal, and a finite strategic resource is lost.
References: [9]
SOLUTION Four layers replaced by Bloomo
Reducing aeration energy
Oxygen supply through photosynthesis partly substitutes for the oxygen supplied to aerobic bacteria. In algae–activated sludge co-culture systems, studies have achieved removal of 86% nitrogen, 70% phosphorus and 99% COD.
References: [10]
Direct CO₂ fixation
Through photosynthesis, microalgae fix about 1.83 tonnes of CO₂ per tonne of biomass. High-concentration CO₂ can also be supplied from flue gas, and at plants co-located with a factory even flue gas containing NOx/SOx can be used.
References: [11]
Recovering nitrogen and phosphorus
NH₄⁺ is assimilated by the algae into amino acids and protein. Combining PBR and MPBR, several studies have achieved removal efficiencies above 90% for nitrogen and above 90% for phosphorus. The recovered biomass feeds into the feed and fertilizer streams.
References: [12][13]
To putting the recovered biomass to workSuppressing N₂O emissions
Constructed wetlands with biochar added have been reported to reduce N₂O emissions substantially. Returning biochar made from Bloomo-recovered biomass to the treatment system is expected to lower overall GHG emissions further.
References: [14][15]
System Architecture Comparison
BENCHMARK Performance indicators (targets, under validation)
| Metric | Conventional process | Bloomo integrated (target) |
|---|---|---|
| Nitrogen removal | 60–85% | > 90% |
| Phosphorus removal | 40–70% (requires chemical dosing) | > 90% |
| Share of energy from aeration | 50–60% of the total | Considerable room to cut (partial substitution) |
| N₂O emission factor | 1.01% kg N₂O-N/kg TN (median) | Designed towards suppression |
| CO₂ fixation | None (an emission source) | 1 t biomass → 1.83 t CO₂ |
Note: the figures for the Bloomo integrated process are targets under validation. There is no track record of large-scale implementation yet; demonstration is under way as the second (Scale Up) phase.
BUSINESS Licensing model
Bloomo for Sewage is rolled out through a licensing model with infrastructure companies and municipalities. Detailed figures on specific customers and market size are provided in confidential materials.
- ▸ The Algal Bloom Capture technology package (strain library, cultivation protocols, AI control know-how)
- ▸ Bloomo Cloud Service (remote monitoring and optimisation)
- ▸ Collaboration models with partner companies (infrastructure companies, municipalities)
ROADMAP Development roadmap
- 1. Cash Cow: proving performance through commercial routes — Bloomo sales to aquaculture operators and seedling production facilities
- 2. Scale Up: demonstrating TRL9 together with infrastructure companies and major fisheries groups (the current phase)
- 3. Water as a Service: shifting to a licensing model, conforming to the EU Water Framework Directive, and integrating into carbon economics
References
- Maktabifard M., et al. Achieving energy neutrality in wastewater treatment plants. Rev. Environ. Sci. Bio/Technol., 2018, 17, 655–689. DOI →
- The Carbon Footprint of Wastewater Treatment Plants (estimate of about 257 MtCO₂eq). Cambi →
- Pathways to a net-zero-carbon water sector through energy-extracting wastewater technologies. npj Clean Water, 2022, 5, 49. DOI →
- Kampschreur M.J., et al. Nitrous oxide emission during wastewater treatment. Water Research, 2009, 43(17), 4093–4103. PMC →
- Stylianou M., et al. Factors Affecting N₂O Emissions from Activated Sludge WWTP — A Review. Resources, 2023, 12(10), 114. DOI →
- Mizuta K., Shimada M. Benchmarking energy consumption in municipal WWTPs in Japan. Water Science and Technology, 2010, 62(10), 2256–2262. DOI →
- (see ref. 3) npj Clean Water (2022), 5, 49.
- Song C., et al. Oversimplification and misestimation of nitrous oxide emissions from WWTPs. Nature Sustainability, 2024, 7, 1348–1358. DOI →
- Mayer B.K., et al. Total Value of Phosphorus Recovery. Environ. Sci. Technol., 2016, 50(13), 6606–6620. DOI →
- Microalgae-based wastewater treatment: Mechanisms, challenges, recent advances. PMC: PMC9557874. PMC →
- Application of microalgae in wastewater treatment with special reference to emerging contaminants. Frontiers in Analytical Science, 2024. DOI →
- Luo Y., et al. Microalgae-Enabled Wastewater Remediation and Nutrient Recovery through MPBR. PMC9660067. PubMed →
- Phosphorus removal from wastewater by microalgal cultivation in PBRs: a systematic review and multivariate analysis. Environ. Monit. Assess., 2025. DOI →
- Zhou X., et al. Pathways and biological mechanisms of N₂O emission reduction by adding biochar in constructed wetlands. 2023. DOI →
- Zhang Y., Zhang Z., Chen Y. Biochar Mitigates N₂O Emission of Microbial Denitrification. Environ. Sci. Technol., 2021, 55(12), 8068–8078. DOI →
Discuss improving your sewage treatment process
Please get in touch about a pilot demonstration, joint research or licensing. Detailed materials are available following an NDA.
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