Nature-Based Solution to Eliminate Cyanotoxins in Water Using Biologically Enhanced Biochar.
Jane MooreAnjali JayakumarSylvia SoldatouOndřej MašekLinda A LawtonChristine EdwardsPublished in: Environmental science & technology (2023)
Climate change and high eutrophication levels of freshwater sources are increasing the occurrence and intensity of toxic cyanobacterial blooms in drinking water supplies. Conventional water treatment struggles to eliminate cyanobacteria/cyanotoxins, and expensive tertiary treatments are needed. To address this, we have designed a sustainable, nature-based solution using biochar derived from waste coconut shells. This biochar provides a low-cost porous support for immobilizing microbial communities, forming biologically enhanced biochar (BEB). Highly toxic microcystin-LR (MC-LR) was used to influence microbial colonization of the biochar by the natural lake-water microbiome. Over 11 months, BEBs were exposed to microcystins, cyanobacterial extracts, and live cyanobacterial cells, always resulting in rapid elimination of toxins and even a 1.6-1.9 log reduction in cyanobacterial cell numbers. After 48 h of incubation with our BEBs, the MC-LR concentrations dropped below the detection limit of 0.1 ng/mL. The accelerated degradation of cyanotoxins was attributed to enhanced species diversity and microcystin-degrading microbes colonizing the biochar. To ensure scalability, we evaluated BEBs produced through batch-scale and continuous-scale pyrolysis, while also guaranteeing safety by maintaining toxic impurities in biochar within acceptable limits and monitoring degradation byproducts. This study serves as a proof-of-concept for a sustainable, scalable, and safe nature-based solution for combating toxic algal blooms.
Keyphrases
- sewage sludge
- heavy metals
- drinking water
- anaerobic digestion
- health risk assessment
- risk assessment
- organic matter
- climate change
- health risk
- low cost
- municipal solid waste
- plant growth
- microbial community
- induced apoptosis
- loop mediated isothermal amplification
- bone marrow
- mesenchymal stem cells
- signaling pathway
- replacement therapy
- genetic diversity
- solid state
- high intensity