Effect of inoculated and uninoculated aeration pretreatment on nutrients and phytotoxicity of anaerobic digestion effluent

Abstract

This study investigates the influence of inoculated and uninoculated aeration pretreatment on nutrients and phytotoxicity of anaerobic digestion (AD) effluent. Swine manure AD effluent was inoculated with activated and anaerobic sludge, respectively. Our results show that aeration with the addition of activated sludge could reduce the phytotoxicity of AD effluent. Compared to the control treatment without any sludge addition, the addition of activated sludge resulted in a more significant reduction in the AD effluent salinity, NH4+ content, and organic matter (indicated by the chemical oxygen demand) when AD effluent was aerated for less than 8 hours. As a result, a much higher seed germination index (GI) was observed for the treatment with activated sludge addition, particularly when aerated for 4–5 hours, contributing the gas/water ratio of 20:1–30:1. On the other hand, no significant differences in the nutrient contents and GI value were observed for the control treatment and that with the addition of anaerobic sludge. Results from this study shed light on optimizing the management of AD effluent for agricultural application.

Biogas digestate as a renewable fertilizer: effects of digestate application on crop growth and nutrient composition

“…Biogas digestate contains fewer harmful pathogens (Furukawa and Hasegawa, 2006) and lower levels of heavy metals (Mukhuba et al ., 2018) compared with raw cattle manure, indicating its viability as a substitute for manure. There are many ways to test (Walsh et al ., 1991; Young et al ., 2012) and treat (Drennan and DiStefano, 2010; Ji et al ., 2017; Zhang et al ., 2018; Xu et al ., 2019) digestate before application to fields, lessening concerns about toxicities to ecosystems. Future investigations should explore how fortification of AD digestate with a micronutrient source benefits crop growth and vegetable production.…”

Improvements on activated sludge settling and flocculation using biomass-based fly ash as activator

“…Therefore, it is important to improve the efficiency of wastewater treatment systems for removing these substances. The addition of adsorbents to activated sludge has shown to improve the efficiency of the aerobic systems 3 . In this process, the porous structures and high surface areas of adsorbents help adsorb pollutants and bacteria 4 .…”