Nitrogen removal enhancement using lactic acid fermentation products from food waste as external carbon sources: Performance and microbial communities

Abstract

In this study, nitrogen removal using the lactic acid fermentation products from food waste and other external chemical carbon sources (sodium acetate, sodium lactate and starch) was investigated. Similar to sodium acetate and lactate, the lactic acid-enriched fermentation liquid from food waste (FLFW) exhibited a high denitrification rate (5.5 mg NO x-N/(g-VSS•h)) and potential (0.16 g NO 3-N/g COD), and could achieve high NH 4 +-N and total nitrogen (TN) removal efficiencies during long-term operation. Using FLFW as supplementary carbon sources reduced the extracellular polymeric substances (EPS) content, improved the settleability and achieved a satisfactory biomass yield of activated sludge. Additionally, the increased microbial metabolic activity and bacterial community diversity and the accumulation of unique bacteria in the activated sludge cultured with FLFW further promoted the organics utilization rate and nitrogen removal efficiency, indicating that the FLFW prepared from solid waste was an ideal 2 carbon source for wastewater treatment.

Volatile fatty acid production from mesophilic acidogenic fermentation of organic fraction of municipal solid waste and food waste under acidic and alkaline pH

“…In comparison with OFMSW, total chemical oxygen demand (COD) of FW (90–170 g L −1 ) is usually almost half than that of OFMSW (150–350 g L −1 ) (Elbeshbishy et al 2011; Lee et al 2014; Strazzera et al 2018). In any case, these two solid wastes are interesting substrates, as they are constantly generated with substantial amount, and, regardless of its possible heterogeneity, they could be efficiently treated through acidogenic fermentation using mixed microbial cultures to produce valuable products like volatile fatty acids (VFAs) and other short-chain organic compounds such as alcohols or lactic acid (Tang et al 2018, 2019).…”

Nutrients removal performance and sludge properties using anaerobic fermentation slurry from food waste as an external carbon source for wastewater treatment

“…Nitrogen (N) and phosphorus (P) discharged from agricultural, domestic and industrial processes can result in the eutrophication of surface waters and deterioration of the environment, which has severely impaired the water quality of aquatic ecosystems around the world (Tang et al, 2018;Feng et al, 2017;Lin et al, 2016). Therefore, it is necessary to remove these nutrients from wastewater treatment systems through biological and physical-chemical methods (Tang e al., 2018; Raudkivi et al, 2017;Klein et al, 2017).…”

“…Soluble organic compounds such as acetate, alcohol and glucose have been utilized as efficient carbon sources for promoting nutrient removal efficiencies (Tang et al, 2018;Liu et al, 2016).…”

“…Based on the principle of "using waste to treat waste", organic wastes such as excess activated sludge and agricultural wastes have been applied in wastewater treatment systems to optimize the carbon sources and promote nutrient removal efficiencies, which has significantly reduced the operation costs (Jia et al, 2018;Nguyen et al, 2014). In recent years, the fermentation products from organic solid wastes and wastewater have also been successfully utilized as additional carbon sources in wastewater treatment (Tang et al, 2017(Tang et al, , 2018Zheng et al, 2018;Liu et al, 2017).…”

“…During anaerobic fermentation, organic wastes are hydrolyzed into dissolved organic matter and acidified into organic acids, which allows microorganisms to use solid wastes more easily, thus further enhancing nitrogen and phosphate removal processes. Our previous work has demonstrated that soluble organics (organic acids and carbohydrates) in the fermentation slurry from food waste (FSFW) are easily biodegradable carbon sources that can obviously increase microbial diversity and significantly promote nitrogen removal efficiency in batch tests and long-term practical operation (Tang et al, 2017(Tang et al, , 2018Zhang et al 2016bZhang et al , 2016c). However, centrifugation and filtration should be applied to separate the soluble fermentation products from the fermented slurry, which is costly and time-consuming.…”