Use of biopolymers as solid substrates for denitrification.

Area of Science:

• Environmental Science
• Microbiology
• Water Treatment

Background:

• Conventional biological denitrification uses dissolved organic carbon (DOC), risking water quality degradation.
• Developing alternative electron donors for denitrification is crucial for sustainable water treatment.

Purpose of the Study:

• To evaluate the denitrification activity of microbial cultures using solid substrates: polycaprolactone (PCL), polylactic acid (PLA), and starch.
• To compare the efficacy of a mixed microbial culture and pure Pseudomonas stutzeri in nitrate removal.

Main Methods:

• Assessing specific denitrification rates using starch, PCL, and PLA as solid substrates.
• Utilizing a mixed microbial culture and a pure culture of Pseudomonas stutzeri.
• Quantifying nitrate reduction in mg N(2)-N/(g VSS.d).

Main Results:

• A mixed microbial culture with starch showed the highest nitrate reduction (104 mg N(2)-N/(g VSS.d)).
• Polycaprolactone (PCL) also demonstrated high activity (97 mg N(2)-N/(g VSS.d)), followed by polylactic acid (PLA) (53 mg N(2)-N/(g VSS.d)).
• Solid substrates significantly reduced the risk of soluble biodegradable organic carbon contamination.

Conclusions:

• Solid substrates like starch and PCL are effective electron donors for water denitrification.
• Biopolymer utilization offers a safer alternative to conventional methods, minimizing water quality risks.
• This approach enhances the sustainability of biological denitrification processes.