Bioremediation of N-Methylmorpholine-N-Oxide: A Scientific Evaluation

N-Methylmorpholine-N-Oxide (NMMO) – a bulk solvent for cellulose in industrial fiber making processes, has high cellulose dissolving capacity and lesser toxicity than CS2 which finds widespread use in the textile industry. In the NMMO process, more than 99% of the solvent is recycled within the process making the fabric eco-friendly. The small quantities released via waste water are readily degraded in the biological waste water treatment plants. As several scientific studies report, it is not mutagenic. Moreover, Amine Oxides find a wide application as active substances of personal hygiene (in hair conditioner, face wash, waxes and polishes), which normally undergo immense toxicological examination, therefore its non-toxicity can be assumed for all practical purposes. However, its degradation and removal from the effluents discharged from industries is a major concern. A reliable study conducted by Meister and Wechsler determined the biodegradability of NMMO in the presence of non activated sewage sludge with 30 mg/L suspended solids. The test period was 28 days; after 28 days on average < 10% biodegradation was observed. The results showed that the substance is not readily biodegradable. However, significant biodegradation was observed when activated sludge was employed showing an ultimate biodegradability of 90 -100%) concluding that the substance is inherently biodegradable when treated with successfully adapted aged sludge involving slowlyreproducing (long-living) sludge organisms which seem to be more efficient degraders of the substance.