Beyond land application: Emerging technologies for the treatment and reuse of anaerobically digested agricultural and food waste

Abstract

Effective treatment and reuse of the massive quantities of agricultural and food wastes generated daily has the potential to improve the sustainability of food production systems. Anaerobic digestion (AD) is used throughout the world as a waste treatment process to convert organic waste into two main products: biogas and nutrient-rich digestate, called AD effluent. Biogas can be used as a source of renewable energy or transportation fuels, while AD effluent is traditionally applied to land as a soil amendment. However, there are economic and environmental concerns that limit widespread land application, which may lead to underutilization of AD for the treatment of agricultural and food wastes. To combat these constraints, existing and novel methods have emerged to treat or reuse AD effluent. The objective of this review is to analyze several emerging methods used for efficient treatment and reuse of AD effluent. Overall, the application of emerging technologies is limited by AD effluent composition, especially the total solid content. Some technologies, such as composting, use the solid fraction of AD effluent, while most other technologies, such as algae culture and struvite crystallization, use the liquid fraction. Therefore, dewatering of AD effluent, reuse of the liquid and solid fractions, and land application could all be combined to sustainably manage the large quantities of AD effluent produced. Issues such as pathogen regrowth and prevalence of emerging organic micro-pollutants are also discussed.

Dairy manure wastewater in serial UASB reactors for energy recovery and potential effluent reuse

“…However, the presence of nutrients may not be correlated with the methane biosynthesis, since both influents showed similar quantities of the aforementioned elements (Table 2 and 3). Low concentrations were detected in the effluent, which is a positive result, since metals such as Fe and Cu can accumulate in agricultural soils (Sheets et al, 2015).…”

Processing, Valorization and Application of Bio-Waste Derived Compounds from Potato, Tomato, Olive and Cereals: A Review

“…The composting process is determined by several factors, such as raw material composition, temperature, humidity, ventilation, pH value, and turning. To achieve a C/N ratio of 20-30 is recommended for digested materials [171][172][173]. Tomato plant stalks and especially culled tomatoes usually contain a high nitrogen concentration.…”

Investigation of surface water quality in magnitogorsk industrial area for the environmental estimation of technogenic watercourse state

“…They are well known mutagenic, carcinogenic, allergic and cytotoxic agents posing threat to all life forms. Work [12] asserts that the effective restoration and reuse of the huge amount of agricultural and food waste generated daily can improve sustainability of food production systems. Anaerobic digestion (AD) is used worldwide as a waste treatment process to convert organic waste into two main products: biogas and a nutrient-rich hydrolyzate called AD wastewater.…”