Optimization of fermented rice noodle wastewater treatment using effective microorganisms (EM)

The treatment of high-strength wastewater generated from fermented rice noodle production poses significant environmental challenges due to its elevated organic load, acidity, and nitrogen content. This study investigated the optimization of wastewater treatment using Effective Microorganisms (EM), focusing on the effects of initial wastewater pH (۶–۸) and EM dosage (۱–۱۰% v/v) on Chemical Oxygen Demand (COD) and Total Kjeldahl Nitrogen (TKN) removal efficiency. A Central Composite Design (CCD) within the framework of Response Surface Methodology (RSM) was employed to model and analyze the interactive effects of these operating parameters. The results demonstrated that near-neutral pH (۶.۹) and a low EM dosage (۱.۲% v/v) yielded the highest COD removal efficiency (۸۰.۲۱%), whereas an alkaline pH (۸.۰) with a low EM dosage (۱% v/v) resulted in the maximum TKN removal efficiency (۷۵.۱۸%). Statistical analysis revealed that EM dosage significantly impacted COD removal (p < ۰.۰۰۰۱), while initial pH had a more pronounced effect on TKN removal (p < ۰.۰۰۰۱). The quadratic regression model exhibited strong predictive performance for both COD (R² = ۰.۹۸۲۷) and TKN (R² = ۰.۹۳۲۶) removal. The findings further indicate that COD removal is predominantly governed by biologically regulated microbial metabolism, whereas TKN removal is controlled mainly by pH-driven physicochemical pathways. Overall, the EM application optimized through RSM represents a promising and sustainable strategy for enhancing the simultaneous removal of organic matter and nitrogen from wastewater generated by the fermented rice noodle industry.

کلیدواژه ها:

Wastewater treatment ، Effective Microorganisms (EM) ، Fermented rice noodles factory ، Response Surface Methodology (RSM) ، Chemical oxygen demand (COD)