Biofuel Produced from Solid-State Anaerobic Digestion of Dairy Cattle Manure in Coordination with Black Soldier Fly Larvae Decomposition

Choon Wee,Jung-Jeng Su

doi:10.3390/en12050911

Abstract

This study was conducted to evaluate the feasibility of applying a two-step biological treatment process, solid-state anaerobic digestion (SSAD) and black soldier fly larvae (BSFL) composting, for the treatment of dairy cattle manure. Biogas from the SSAD of dairy cattle manure, and the digestate of SSAD was fed to BSFL. In turn, BSFL can be fed to animals as a protein supplement. Adjustment of the pH and 30% inoculation ratio (IR30) during SSAD produced the highest theoretical methane yield, 626.1 ± 28.7 L CH4/kg VSdes, with an ultimate methane yield of 96.81 ± 2.0 L CH4/kg VSload. For BSFL composting, the groups with a feeding rate of 75 and 100 mg/day/larvae had the highest body weight change, which was 969.6 ± 28.4% and 984.1 ± 177.6%, respectively. The combination process of SSAD and BSFL composting increases the incentive for dairy cattle manure treatment instead of conventional composting and produced more valuable products.

Highlights

With a growing population that is expected to reach approximately 9.7 billion by 2050, the worldwide production of milk is estimated to grow from 580 million tons in 1999 to 1043 million tons in 2050, and global meat production is estimated to increase from 229 to 456 million tons [1].In 2015, there were 146,030 heads of dairy cattle in Taiwan [2]
By Fresh Cattle that two peaks of biogas yield occurred during days 1 to 7 and days 30 to 34 (Figure 3a)
The methane content increased from that two peaks of biogas yield occurred during days 1 to 7 and days 30 to 34 (Figure 3a)

Summary

Introduction

With a growing population that is expected to reach approximately 9.7 billion by 2050, the worldwide production of milk is estimated to grow from 580 million tons in 1999 to 1043 million tons in 2050, and global meat production is estimated to increase from 229 to 456 million tons [1]. In 2015, there were 146,030 heads of dairy cattle in Taiwan [2]. Dairy cattle manure is commonly treated using both wastewater treatment and composting technology in Taiwan. A three-step wastewater treatment system that includes solid-liquid separation, anaerobic digestion, and aeration is used to treat dairy and piggery wastewater [3]. Composting is used to treat mainly the solid fraction of dairy cattle or pig manure. The solid fraction of dairy cattle manure can be used as a feedstock for anaerobic digestion

Objectives

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Results

Conclusion