Combined approach for soybean wastewater chemical oxygen demand reduction using Aspergillus niger pelletization technology

Jianguo Zhang,Yan Zhang,Ningning Diao

doi:10.1080/13102818.2016.1262751

Abstract

ABSTRACTUsing biological processes to treat soybean wastewater has great potential, because it generates biomass and reduces sludge production. The formation of Aspergillus niger pellets during cultivation in wastewater has the additional benefit that such pellets are easy to harvest. In the first wastewater treatment step, A. niger pelletization decreased the chemical oxygen demand (COD) by 80.35%. In the second step, A. niger, when combined with added nutrients and cultivated in the presence of Pichia pastoris, did not decrease the COD. Aspergillus niger did not degrade some carbon compounds according to total carbon, organic carbon, and inorganic carbon analysis. The COD decreased from 3.26 × 104 mg O2/L to 616.67 mg O2/L (a 98.11% COD reduction) after activated carbon absorption, which indicates that this approach is efficient. In summary, this study proposes a combined method to treat high-COD-value soybean wastewater.

Highlights

Soybean foods, such as tofu, soy yoghurt, natto, soy sauce, tempeh, soy cheese, sufu, soymilk, soybean sprouts, and soy protein, are widely eaten in Asia
The increasing pH indicated that the A. niger cells lysed, which was consistent with the constant biomass from 120 to 192 h of cultivation
The macro-morphology of the A. niger pellets did not change significantly, the pellets became grey as the incubation time went on (Figure 2)

Summary

Introduction

Soybean foods, such as tofu, soy yoghurt, natto, soy sauce, tempeh, soy cheese, sufu, soymilk, soybean sprouts, and soy protein, are widely eaten in Asia. This study proposes a combined method to treat high-COD-value soybean wastewater. KEYWORDS Aspergillus niger; chemical oxygen demand; pellets; soybean wastewater treatment This study developed an efficient approach to treat soybean wastewater using A. niger, and the COD was reduced efficiently via an activated carbon absorption process.

Results

Conclusion