The composition of microalgae biomass is a critical factor determining its downsteam utilization potential. Both reactor type and culture medium composition have be indicated exert significant influences on microalgal composition. This study investigated the cultivation of Chlorella sp. in bench-scale ponds using anaerobic digestion wastewater as the culture medium, with the BG11 standard culture medium was set as control.This study focused on evaluating the effects of open and closed reactor systems on nutrients removal from wastewater by microalgae, while analyzing the ion content of microalgal biomass to clarify its compositional characteristics. Results demonstrated that the ash content, lipid content, and protein content of microalgae cultivated in the closed system were approximately 3

Ammonia inhibition can have toxic effects on anaerobic digestion (AD) and is detrimental to smooth operation of AD. To enhance methane production of the AD under ammonia inhibition, this study investigated the effect of addition of Fe3O4@biochar on the methanogenesis process of AD at different ammonia nitrogen (AN) level. Fe3O4@biochar significantly enhanced methane production by 11.3-183.6 % at NH4+-N concentrations from 1200 to 6000 mg/L. Microbial community analysis revealed that Fe3O4@biochar alleviated the inhibition via promoting the enrichment of ammonia-tolerant flora associated with electron transfer and upregulating the expression of related genes. The enriched unclassified Clostridiales degrade acetic acid and could be involved in electron transfer with Methanosarcina as potential electron transfer partner. Meanwhile, the high expression of methylenetetrahydrofolate cyclohydrogenase and methylenetetrahydrofolate dehydrogenase in the Wood-Ljungdahl pathway further demonstrated that the increase of methane yield under ammonia inhibition was associated with the enhancement of the SAO-HM pathway. This study provided theoretical guidance for the regulation of AD under different concentrations of ammonia inhibition.

Anaerobic digestion (AD) is one of the key technologies to achieve energy and nutrient recovery from organic waste. Obtaining inoculum with highly-active functional microbes and low moisture content is crucial to startup of the newly built large-scale AD. Therefore, different concentration methods, including chemical flocculation (cationic polyacrylamide (CPAM), poly aluminum chloride (PAC), and poly ferric sulfate (PFS)) and physical centrifugation (1000 rpm, 2000 rpm), were applied in this study to investigate their effects on the volume reduction of inoculum and on the microbial density and functional community. The results showed that the inoculum volume was reduced by 90 % and 73 %, respectively, after the centrifugation and flocculation. In the following AD startup experiment, the concentrated inoculum (Concentrate group) increased methane production up to 35 % compared to the original inoculum (Ctrl group). Microbial analyses demonstrated that the dominant protein-degrading bacteria was switched from Fastidiosipila in the Ctrl group into Proteiniphilum and Fermentimonas in Concentrate group. Meanwhile, the dominant carbohydrate-degrading genera was changed from M55D21_genus into Ruminofilibacter. Moreover, the absolute abundance of Fermentimonas, and Ruminofilibacter were significantly higher in the centrifugation treatment (9.88 x 107 copies/g and 3.64 x 107 copies/g) than in the flocculation treatment (3.47-4.21 x 107 copies/g and 1.41-2.35 x 107 copies/g), indicating the advantage of centrifugation over flocculation. The absolute abundance of methanogens in all Concentrate groups (5.53 x 106- 1.95 x 107 copies/g) were significantly higher than the Ctrl group (6.64 x 105 copies/g), while Methanosarcina was the predominant genus. The key functional enzyme analysis based on PICRUST2 methodology, such as EC:1.2.7.12 and EC:6.2.1.1, implied that the primary methanogenic pathway was hydrogenotrophic methanogenesis, followed by acetoclastic methanogenesis. Overall, the findings derived from this study provide efficient inoculum concentration method for the startup of full-scale AD plants.

The world is facing both an increasingly severe energy crisis and a growing problem of agricultural pollution. The utilization of agricultural waste by anaerobic digestion (AD), has received increasing attention. AD using representative waste cow dung results in total ammonia nitrogen (TAN) accumulation and inhibition of methanogens resulting in reduced CH4 production. However, there is a lack of highly efficient in-situ biological domestication strategies to enhance the TAN tolerance of methanogens in AD systems. In this study, an incremental approach to gradually increasing the TAN concentration has been used for overcoming the problem. The results showed that at an ultra-high concentration of 6124.09 mg/L TAN, a 48-day domesticated AD system functioned stably and the cumulative CH4 production reached 72.81 mL/g volatile solids, whereas the undomesticated AD system failed to produce CH4. After domestication, the lactate dehydrogenase concentration decreased to 96.44 ng/L and the adenosine triphosphate concentration increased to 48.77 nmol/L, confirming that microbial activity improved. Hydrolytic and acidogenic bacteria were enriched, with Methanosarcina (79.73

Large amounts of biogas slurry and digestate waste not only impose an environmental burden, but also hinder the further development of anaerobic digestion. Hydrothermal carbonization (HTC) facilitates the valorization of high-moisture solid waste. In this study, the effect of initial pH (2.5-13.5) of biogas slurry on nitrogen (N) transformation during the HTC of livestock manure digestate was investigated. The migration of N was closely related to pH, and acidic environment effectively enriched N in hydrochar (HC). The N element in HC was mainly presented in heterocyclic forms, with pyridine-N and quaternary-N being the most stable. The N content of HC at pH 2.5, 4, and 6 was 2.10 %, 1.81 %, and 2.28 %, respectively. And the corresponding sum proportion of pyridine-N and quaternary-N was 55.08 %, 39.76 %, and 35.53 %, which was significantly higher than in alkaline environment. Compared with HC-8 (HC obtained at pH 8), the C and N contents in HC 2.5-6 increased by 12.80 % - 45.71 % and 17.53 % - 48.05 %, respectively, indicating C and N contents were higher in HC prepared under acidic conditions compared to neutral and alkaline conditions. Results indicated that the acidic environment promoted the formation of pyridine-N and quaternary-N, which strengthened the Maillard and Mannich reactions. In contrast, alkaline environment hindered protein hydrolysis and suppressed the polycondensation of pyrrole-N. The results provide a basis for pH regulation to control N species in HC, optimizing the HTC process for efficient N recovery and high-value waste utilization.

In order to enhance the start-up of anaerobic digestion (AD), the propionate-degrading methanogenic cultures were introduced to AD of food waste at a high organic loading rate (OLR) of 3.0 g VS/L center dot d in this study, and the efficiency of different bioaugmentation strategies were investigated. The results demonstrated that bioaugmentation significantly improved the start-up efficiency and enhanced the methane production. Specifically, higher dosage and frequency of bioaugmentation had a positive effect on the performance of the AD reactors. Among three bioaugmented reactors, the reactor with a bioaugmentation strategy of 0.675 g VS/L of bioaugmentation seed added every 5 d during the first hydraulic retention time (HRT) performed the best and remained relatively stable for the next three HRTs without bioaugmentation. The 16S rRNA gene sequencing analysis revealed that Methanothrix predominated in bioaugmented reactors. A large proportion of Methanothrix accompanied by a small proportion of Methanospirillum played a key role in volatile fatty acid degradation and contributed to the successful start-up and long-term stability of AD at a high OLR. These findings suggest that bioaugmentation with methangenic consortium is a promising strategy to boost the AD process at high OLRs and achieve higher treatment capacity of food waste.

High total ammonia nitrogen (TAN) inhibits anaerobic digestion (AD) and cannot be completely eliminated by merely enhancing a stage of AD. This study incorporates TAN‐tolerant inoculum into substrates hydrolyzed by Rhizopus mixed agents to simultaneously enhance hydrolysis‐acidogenesis‐methanogenesis. The results show a 16.46‐fold increase in CH4 production under TAN‐inhibited (6870.97 mg L−1) conditions, even exceeding the AD without TAN by 21.10%. Model substrates sodium acetate and mixed H2 confirm hydrogenotrophic methanogenesis is the main pathway, with reduced TAN inhibition. Furthermore, a synergistic metabolic microbial community dominated by hydrolytic bacteria JAAYGG01 sp. and DTU014 sp., acidogenic bacteria DTU015 sp., DTU013 sp., and JAAYLO01 sp., and methanogens Methanosarcina mazei and an unclassified species in the Methanoculleus is reconstructed to resist TAN inhibition. Metagenomic combined with metatranscriptomic sequencing identifies that this microbial community carries xynD and bglB to regulate substrate hydrolysis, leading to acetate production through glycolysis, butyrate, and pyruvate metabolism with high acetate kinase activity, thereby CH4 produced primarily via hydrogenotrophic methanogenesis with high coenzyme F420 activity, facilitated by efficient mass transfer processes and quorum sensing regulation. This cleaner strategy obtains higher economic benefit (US$149.02) than conventional AD and can increase 154.64‐fold energy production of a 24 000 m3 biogas plant, guided by machine learning.

Microalgae are considered promising for wastewater treatment and nutrients recovery. However, microalgae from wastewater usually have a high ash content, which significantly influences on the utilization efficiency of microalgae. In this study, poultry wastewater with different salinity levels was used to cultivate Chlorella sp. in bench-scale ponds. The ion content of the microalgal ash was tested to determine the composition of the ash. The results show that microalgae cultivated in wastewater with higher salinity results in a high ash content, and the ash content of microalgae from fertilizer wasterwater (FW) has a positive linear relationship with the initial salinity of FW. The ash content of microalgae in wastewater with 3.59 g L-1 salinity is 12.5% higher than that in wastewater with 1.50 g L-1 salinity. The main compounds of microalgal ash from FW runs were CaO, P2O5, MgO, SiO2, and K2O (over 5%). The highest removal rates of NH4+-N, TP, and TOC in the FW runs were 99.1%, 93.7%, and 80%, respectively. Except for FW-16, the lipid and protein contents of microalgae from FW runs showed a positive relationship with the dilution ratios. This research aims to propose a way to reduce the microalgae ash when coupling microalgae cultivation with the wastewater.

The accumulation of volatile fatty acids (VFAs) in anaerobic digestion (AD) systems resulting from food waste overload poses a risk of system collapse. However, limited understanding exists regarding the inhibitory mechanisms and effective strategies to address VFAs-induced stress. This study found that accumulated VFAs exert reactive oxygen species (ROS) stress on indigenous microbiota, particularly impacting methanogens due to their lower antioxidant capability compared to bacteria, which is supposed to be the primary reason for methanogenesis failure. To enhance the VFAs-stressed AD process, microbiome re-assembly using customized propionate-degrading consortia and bioaugmentation with concentrated digestate were implemented. Microbiome re-assembly demonstrated superior efficiency, yielding an average methane yield of 563.6±159.8 mL/L·d and reducing VFAs to undetectable levels for a minimum of 80 days. This strategy improved the abundance of Syntrophomonas, Syntrophobacter and Methanothrix, alleviating ROS stress. Conversely, microbial community in reactor with other strategy experienced an escalating intracellular damage, as indicated by the increase of ROS generation-related genes. This study fills knowledge gaps in stress-related metabolic mechanisms of anaerobic microbiomes exposed to VFAs and microbiome re-assembly to boost methanogenesis process.

为降低鸡粪沼液对环境污染的同时寻求资源的再生利用,以鸡粪沼液膜过滤出水作为小球藻培养基,研究了二氧化碳(CO2)体积浓度(0.03％ ～10％)及氮磷比(N/P=10～260)对小球藻生物量与色素累积,以及对氨氮、磷酸盐去除的影响.试验结果表明:在CO2体积浓度为7.5％、N/P=80的条件下,小球藻干重最高可达3.38 g·L-1,叶绿素(Chlorophyl,Chl a+b)浓度为30.78 mg·L-1,氨氮去除率为68.6％.CO2浓度对小球藻累积生物量的影响更大,培养20 d后,额外补偿CO2的各处理组中磷酸盐去除率均>98％.研究为鸡粪沼液膜过滤出水培养微藻的工业化应用奠定了基础.

Using microalgae to treat biogas slurry can realize wastewater treatment and nutrients recovery. However, the dark color of biogas slurry causes serious light attenuation. Flashing light was used to solve light attenuation, while improving biomass production and pollutant removal. Higher frequency (f) and lower duty cycle (φ) flashing light conditions increased biomass concentration and pollutant removal. With 100 Hz-0.3 φ-60 μmol photons m−2 s−1, the biomass concentration, biomass productivity and NH4+-N removal reached the highest values of 255 mg L−1, 8.45 mg L−1 day−1 and 55.2

为研究"新壮态"有机液体叶面肥与冲施肥在花生上的施用技术和应用效果,在山东莱西、辽宁阜新和江西赣州进行叶面肥试验,在阜新进行膜下滴灌模式下的冲施肥试验.结果表明,叶面肥试验,在赣州花生生育中期和前期(花针期与苗期)施用增产效果较好,莱西、阜新试验数据则分别显示在花生生育后期和中期(饱果期和花针期)、后期(饱果期)喷施增产效果较好;莱西试验产量最优处理饱果期叶面肥300X比空白对照蛋白质含量和油酸含量提高,含油量和亚油酸含量降低,更适合食用;在赣州调查,喷施"新壮态"叶面肥的花生植株叶斑病、锈病和白绢病发病较轻;膜下滴灌冲施肥试验,以饱果期浓度105L·hm-2产量最优;叶面肥试验和膜下滴灌冲施肥试验最优处理相比空白对照增产10％以上,净增收超过1950元·hm-2.

以番茄为试验材料,通过田间试验研究沼液提取物与宛氏拟青霉菌(菌株SJ1)复配对番茄生长和果实品质的影响.结果表明,沼液提取物与宛氏拟青霉菌复配叶面肥能够促进番茄生长,提高番茄产量,可以替代化学叶面肥.其中,沼液提取物500倍液和宛氏拟青霉菌30 ng·mL-1复配作叶面肥的综合效果最佳,与施用化学叶面肥处理相比,番茄植株鲜质量、干质量、壮苗指数、POD活性、开花数、坐果数、坐果率分别提高43.06％、28.43％、84.74％、28.06％～78.13％、30.30％、68.86％、29.51％.果实可溶性蛋白含量、可溶性糖含量和产量分别提高28.44％、146.61％、75.13％.综上所述,沼液提取物500倍液和宛氏拟青霉菌30 ng·mL-1复配作叶面肥可在生产中推广使用.

[目的]明确鸡粪沼液与化学农药噻虫胺减量混用对韭菜迟眼蕈蚊的防治效果.[方法]分别采用胃毒触杀法和灌根法进行室内毒力测定和田间药效试验.[结果]鸡粪沼液稀释50倍与1 mg/L噻虫胺减量10％～40％混用,对韭菜迟眼蕈蚊3龄幼虫的毒力与1 mg/L噻虫胺差异不显著.鸡粪沼液50～100倍在药剂减少20％的情况下,桶混制剂对韭菜迟眼蕈蚊的田间防效与噻虫胺常规剂量相当.[结论]在使用噻虫胺防治韭菜迟眼蕈蚊时,建议鸡粪沼液稀释50～100倍,与噻虫胺减量20％混用.

Poultry manure anaerobic digestion effluent (PMADE) contained a high content of ammonia nitrogen (NH4+-N), which should be treated properly before discharge. However, the mechanism of electrolysis in treating high NH4+-N (over 1,500 mg L-1) wastewater has never been studied. In this study, fertilizer wastewater from PMADE with high content of NH4+-N (over 3,000 mg L-1) and low carbon/nitrogen (C/N) ratio was treated via electrolysis and microalgae. Results showed the highest removal of NH4+-N, total organic carbon (TOC) and inorganic carbon (IC) in electrolysis were 47%, 76%, and 93%, respectively. Quadratic functions are suitable to simulate NH4+-N removal of FW (coefficient is over 0.95). The removal efficiency of NH4+-N was 10%-65% during microalgae cultivation. The removal of NH4+-N, total phosphorus (TP), IC, and TOC in fertilizer wastewater by the combination of electrolysis and microalgae cultivation achieved 96%, 63%, 95%, and 52%, respectively. Chlorella sp. used 3.11% carbon, 15.0% nitrogen, and 13.5% phosphorus in the FW as substrates. This study provided an alternative approach to treat and reuse high-ammonia containing wastewater.

To increase the knowledge of microbial adaptation for high degradation ability under ammonia stressed conditions, the metabolic performance and the microbial community in a full-scale chicken manure anaerobic digestion (AD) plant, operated over a 10-year, were investigated. The methanogenic pathway employing labeled acetate (2-C-13), aceticlastic methanogenesis activity, and the Illumina sequencing of microbiome structure at the plant were analyzed. The obtained results show that this active plant achieved a methane yield of 310 +/- 43 mL/g-volatile solids (VS), high stability under an ammonium-N level of 6.2 +/- 0.1 g/L, and an organic loading rate of 2.5 g-VS/(L.d). The extremely long adaptation developed the unique microbe communities, and the hydrogentrophic methanogens Methanobrevibacter (76%) and Methanoculleus (18%) were dominant in the main digester. The acetoclastic methanogenic pathway reached 42%, contributing to the deep degradation. The current study thus may lay the foundation for illustrating the successful full-scale AD of nitrogen-rich materials under stressed operating conditions. (c) 2020 Elsevier Ltd. All rights reserved.

China has promoted its biogas industry for a long time and begun to support bio-natural gas (BNG; also known as biogas upgrading or biogas-to-biomethane) projects for the first time in 2015 at the central government level. This study presented a comprehensive overview of the BNG industry in China, including its status quo, national strategic planning, upgrading technologies, investment cost, potential, and opportunities and challenges. A total of 65 BNG demonstration projects were approved by the central government between 2015 and 2017, and 197 projects are expected to have been built by 2020 as part of the 13th Five-Year Plan (2016–2020). BNG is an emerging industry, and its development provides several opportunities, including a huge natural gas demand, national policy incentives, integrated agriculture, and reduced carbon emissions. The challenges and barriers to such developments include the high upgrading cost, fluctuating natural gas prices, unsound market access mechanism for biomethane and biofertilizer, scarce competition-oriented feedstock resources, incomplete standard system and cross-sectorial management, imperfect policy and subsidy mechanism, and lagging technology and equipment. China can learn from other developed countries in four ways. First, the country must enhance the cost effectiveness of its subsidies. Then, China must highlight the operations of its BNG industry and evaluate its performance; prioritize digestate management in the planning stage; improve its project service level and reinforce research and development. The findings of this work provide a valuable reference for other developing countries that intend to address energy shortage issues and integrate waste management into their regional planning.

针对国内畜禽粪便资源化利用存在的利用率低、循环体系不完善、市场化水平低等问题,基于山东民和生物科技股份有限公司畜禽粪便资源化循环利用的产业模式,重点探讨畜禽粪便如何高效资源化产出、产出品如何实现高值化循环利用、产业链价值如何全面提升.通过畜禽粪便沼气能源化与肥料化处理方式互补,形成畜禽粪便商品有机肥生产、沼气热电联产、沼气提纯生物天然气、沼液浓缩有机水溶肥料高值利用的资源化利用体系,横向拓展、纵向延伸,构建畜禽粪便资源化循环利用全产业链模式,使物质高效循环、能量多级利用、产出品向高值化方向移动,在"三化一销"市场化运营管理模式下,全面提升经济、环境、生态、社会效益,为规模化畜禽粪便资源化利用提供参考.

Microalgae using non-arable land were considered as promising biomass for biocrude production through hydrothermal liquefaction (HTL) and can also be used for environmentally-friendly wastewater treatment. In this study, we illuminated the effect of reaction temperature on the products distribution and biocrude properties from HTL of the Chlorella sp. grown in wastewater from anaerobic digestion (AD) of chicken manure via HTL. The highest biocrude yield (30.35%, daf) and energy recovery rate (49.6%) were both achieved at 330 degrees C, while the highest HHV (37.17 MJ/kg) of biocrude oil was achieved at 290 degrees C. The biocrude oil yield increased from 25.46 to 30.35% as the temperature increased from 270 to 330 degrees C. The gases yield showed a similar trend under 310 degrees C. On the contrary, the solid products yield decreased as the temperature approached 350 degrees C. The lowest nitrogen content (4.6%) and highest H/C (1.50) of biocrude oil were obtained at 290 and 270 degrees C, respectively. Results imply that deoxygenation was enhanced with temperature due to the enhanced decarboxylation at higher temperatures. Specially, the nitrogen content decreased by 39.4-47.4% in the temperature range of 270-350 degrees C. The integrated pathways for energy production and nutrient recycling from animal manure coupling AD/HTL, and algae technologies were further proposed.

Nutrients and water play an important role in microalgae cultivation. Using wastewater as a culture medium is a promising alternative to recycle nutrients and water, and for further developing microalgae-based products. In the present study, two species of microalgae, Chlorella sp. (high ammonia nitrogen tolerance) and Spirulina platensis (S. platensis, high growth rate), were cultured by using poultry wastewater through a two-stage cultivation system for algal biomass production. Ultrafiltration (UF) or centrifuge was used to harvest Chlorella sp. from the first cultivation stage and to recycle culture medium for S. platensis growth in the second cultivation stage. Results showed the two-stage cultivation system produced high microalgae biomass including 0.39 g·L–1Chlorella sp. and 3.45 g·L–1S. platensis in the first-stage and second-stage, respectively. In addition, the removal efficiencies of NH4+ reached 19% and almost 100% in the first and the second stage, respectively. Total phosphorus (TP) removal reached 17% and 83%, and total organic carbon (TOC) removal reached 55% and 72% in the first and the second stage, respectively. UF and centrifuge can recycle 96.8% and 100% water, respectively. This study provides a new method for the combined of pure microalgae cultivation and wastewater treatment with culture medium recycling.