Search

In this study, mannitol and mannitol-rich seaweed were fermented to investigate the relationship between substrate reduction degree and hydrogen production performance. The results showed that acetate was required in mannitol fermentation with an optimum acetate/mannitol mass ratio of 1:5. Hydrogen production and yield of mannitol fermentation reached 123.76 mL and 2.12 mol/mol-mannitol, respectively, 42.02 % and 26.95 % higher than that of glucose, respectively. The acetate was fully assimilated and the butyrate selectivity reached 100 % in the effluent. Redox potential and electron distribution showed that mannitol increased the overall electron input from mannitol and acetate, leading to the increase in hydrogen and butyrate generation. Hydrogen yield reached 2.33 mol/mol-mannitol with brown algae hydrolysate, which was the highest ever reported. This study demonstrated that substrate with a higher reduction degree could yield higher hydrogen and showed the great application potential of brown algae fermentation for the co-production of hydrogen and butyrate.

The air cathode of microbial fuel cells (MFCs) facing wastewater is easily coated with microbes to cause catalyst poisoning, resulting in the serious decline of electricity generation and wastewate...

Batch experiments were conducted to study bioelectrochemical enhancement of the anaerobic digestion (AD) of alkaline-pretreated sewage sludge in microbial electrolysis cell (MEC) in the presence or absence of phosphate buffer solution (PBS). Experimental results showed that the maximum methane production rate was increased from 0.18 mL-CH4/(mLreactor·d) (control) to 0.2 mL-CH4/(mLreactor·d) in the presence of PBS and cumulative methane production was 1.4-fold higher than that of control. The initial concentrations of SCOD, protein, polysaccharide and VFAs in the presence of PBS were slightly higher than those of control, suggesting that PBS might facilitate the release of organics into mixed liquor. The microbial community analysis results showed that the microbial community with PBS had higher diversity and Bacteroidetes and Firmicutes were the two most abundant phyla in the communities. Moreover, the PBS addition could enhance the growth of aceticlastic methanogens (Methanosaeta) and inhibit a portion of hydrogenotrophic methanogens (Methanobacterium), possibly due to the different cell wall composition.

In lignocellulose-to-hydrogen bioconversion, reducing the concentration of chemical agents in pretreatment is of great interest. In this study, rice straw (RS) pretreated at reduced NaOH and urea (NU) concentrations was evaluated. Results showed that the composition of RS exhibited excellent pretreatment performance at a reduced concentration of NU. When the concentration of NaOH was decreased to 3 wt% in combination with 6 wt% urea, the lignin was reduced by 59.52% with a cellulose and hemicellulose loss of less than 17%. Moreover, extending the pretreatment time at a low concentration of NU could effectively promote the biodegradability of RS. Upon fermentation by Thermoanaerobacterium thermosaccharolyticum M18 for H2 production, the H2 production increased up to 213.06 mL/g with a substrate treated by 3 wt% NaOH/6 wt% urea at low solid loading for 15 d, which was 16.31% higher than the counterpart subjected to a 7 wt% NaOH/12 wt% urea pretreatment. The present results suggest the NU pretreatment can be carried out at low concentrations to improve the conversion of RS into bio-H2 production.

As a clean and renewable energy, bioenergy is one of the most promising alternatives to fossil fuels. Lignocellulose possesses great potential for bioenergy production, but the recalcitrant and heterogeneous structure limits its application. Pretreatment technology offers an effective solution to fractionate the main components of the lignocellulose and uncover the available cellulose. The obtained feedstock can be applied to bioconversion into energy, e.g., bioethanol, biogas, biohydrogen, etc. Here, the current state of lignocellulose pretreatment technologies was comprehensively reviewed, the advances in bioenergy production from pretreated lignocellulose was described, with particular attention to key challenges involved. Several new strategies for overcoming pretreatment barriers to realize highly efficient lignocellulose bioconversion were highlighted. The insights given in this review will facilitate further development on lignocellulosic bioenergy production, towards addressing the global energy crisis and climate change related to the use of fossil fuels.

Background Microalgae as a viable biodiesel feedstock show great potential to approach the challenges of energy shortage and environment pollution, but their economic feasibility was seriously hampered by high production cost. Thus, it is in urgent need to reduce the cost of cultivation and improve the biomass and lipid production of microalgae. In this work, anaerobic digestion effluent from cattle manure combined with municipal wastewater was used as a cost-effective medium for cultivating microalgae and expected to obtain high biomass. The pretreatment of anaerobic digested effluent containing dilution rate, sterilization and nutrient optimization was investigated. Then, initial pH and light intensity for algal growth, lipid production and wastewater purification were optimized in this study. Results Scenedesmus sp. could grow rapidly in 10% anaerobic digestion effluent from cattle manure combined with secondary sedimentation tank effluent without sterilization. Optimum nutrient additives for higher biomass were as follows: glucose 10 g/L, NaNO3 0.3 g/L, K2HPO4·3H2O 0.01 g/L, MgSO4·7H2O 0.075 g/L and trace element A5 solution 1 mL/L. Biomass of 4.65 g/L and lipid productivity of 81.90 mg/L/day were achieved during 7-day cultivation accompanying over 90% of COD, NO3−-N, NH4+-N, and 79–88% of PO43−-P removal with optimized initial pH of 7.0 and light intensity of 5000 l×. The FAME profile in ADEC growth medium consisted in saturated (39.48%) and monounsaturated (60.52%) fatty acids with the 16- to 18-chain-length fatty acids constituting over 98% of total FAME. Conclusions This study proves the potential of anaerobic digested effluent combined with municipal wastewater for microalgae culture, and provides an effective avenue for simultaneous microalgal lipid production and treatment of two kinds of wastewater.

To enhance photo-fermentative hydrogen production (PFHP), biofilm reactor (BR) was employed as an ideal strategy with optimization on key factors of acetate concentration and carriers in this work. Optimal conditions for hydrogen production were acetate concentration of 4 g/L and carriers (silicon sheet) of 10 cm × 1 cm at amount of 1 piece. Biofilm formed on silicon sheet strongly improved hydrogen production compared with control reactor (CR). Cumulative hydrogen volume was enhanced about 20% from 2850 ± 130 mL/L of CR to 3349 ± 153 mL/L of BR and hydrogen yield was increased 20% from 2.61 ± 0.13 mol H2/mol acetate of CR to 3.06 ± 0.15 mol H2/mol acetate of BR at 4 g/L acetate. Protein and deoxyribonucleic acid (DNA) were important components to form the biofilm and they occupied 90% of extracellular polymeric substances (EPS). In particular, DNA, nearly 50% content of EPS, likely indicated a substantial contribution to biofilm formation and bacterial communication. Moreover, it suggested biofilm could regulate free cells to decline EPS secretion for improved hydrogen production. This work indicates BR could be a promising and economic strategy to enhance hydrogen production by photo-fermentation.

An innovative approach is developed to utilize the frass of mealworms (Tenebrio molitor Linnaeus 1758) for producing dye-removal biochar. Agricultural waste wheat straw (WS) was tested as feedstock versus wheat bran (WB) to rear mealworms for the production of insect biomass. Mealworms on WS grew at a slightly slower rate than those grown on WB for 32 days with ∼40% lignin removed at 25 °C. Biochars were generated using the frass of mealworms via pyrolysis. The best adsorption performance for three dyes, especially malachite green, a cationic dye, was the biochar of WS frass at 800 °C; it had better capacity (1738.6 mg/g) compared with the frass fed with bran, raw WS and raw WB as well as those reported in the literature. Adsorption of malachite green fits the Langmuir isotherm and the pseudo second order kinetic model, mainly due to chemisorption and electrostatic interaction. Our results demonstrated that the WS can be utilized to rear mealworms, and that frass of mealworms is an excellent raw material for generating high-efficiency bioadsorbents.

The performance and microbial community succession of a 36 L working volume plug flow reactor was evaluated for treated cattle manure at an organic loading rate of 2.67 g-TS/L/day, a temperature of 38 °C ± 1 °C, and a hydraulic retention time of 18 days. A reflux of acidizing fluid effectively enhanced anaerobic digestion performance and promoted optimization of microbial community structure. The average biogas volume production rate was 1.08 L biogas/L reactor, which was 116.5% higher than the control without reflux of acidizing fluid. The specific qmethane production yield and methane content reached 0.204 L/g VS and 70%. Moreover, methane yield achieved 0.34 m3/kg removal COD with a COD removal of about 70.56%. The bacteria genera Christensenellaceae, Bacteroidales, vadinBC27, Ruminococcaceae and Treponema_2 were further enriched. Methanosarcina became the dominant methanogen in the whole PFR operation process. This study offers new opportunities for producing renewable energy from enhanced cattle manure biodegradability.

Hydraulic retention time (HRT) is the main process parameter for biohydrogen production by anaerobic fermentation. This paper investigated the effect of the different HRT on the hydrogen production of the ethanol-type fermentation process in two kinds of CSTR reactors (horizontal continuous stirred-tank reactor and vertical continuous stirred-tank reactor) with molasses as a substrate. Two kinds of CSTR reactors operated with the organic loading rates (OLR) of 12kgCOD/m3•d under the initial HRT of the 8 h condition, and then OLR was adjusted as 6kgCOD/m3•d when the pH drops rapidly. The VCSTR and HCSTR have reached the stable ethanol-type fermentation process within 21 days and 24 days respectively. Among the five HRTs settled in the range of 2–8 h, the maximum hydrogen production rate of 3.7LH2/Ld and 5.1LH2/Ld were investigated respectively in the VCSTR and HCSTR. At that time the COD concentration and HRT were 8000 mg/L and 5 h for VCSTR, while 10000 mg/L and 4 h for HCSTR respectively. Through the analysis on the composition of the liquid fermentation product and biomass under the different HRT condition in the two kinds of CSTR, it can found that the ethanol-type fermentation process in the HCSTR is more stable than VCSTR due to enhancing biomass retention of HCSTR at the short HTR.

Heteroatoms-doped carbon-based materials (with non-precious metals or no metals) with porous structure have already shown high catalytic activities for oxygen reduction reaction (ORR), especially in microbial fuel cells (MFCs). Here, we use pectin extracted from pomelo peels as carbon source to prepare metal-free and sulphur/nitrogen co-doped partially-graphitized carbon (HP-SN-PGCs) by using silica nanospheres as sacrificial templates. Single-chamber MFC (SC-MFC) with HP-SN-PGC-0.5 (0.5 g of silica) cathode has the shortest start-up time (45 h) and lowest charge transfer resistance (19.3 Ω). The maximum power density of HP-SN-PGC-0.5 (1161.34 mW m−2) cathode is higher than that of Pt/C (1116.90 mW m−2) at the initial cycle. After 75 d operation, power density of HP-SN-PGC-0.5 cathode only declines 4.6%, which is more stable than that of Pt/C (37.69%). HP-SN-PGC-0.5 has a highly porous structure (869.25 m2 g−1) by removal of templates and Fe species (as the graphitization catalyst) to facilitate exposure of active sites and diffusion of ORR-related intermediates (OH− and HO2−, etc) to accessible active sites. N and S species provide highly active sites to enhance OH− generation to conduct the 4e− ORR process. Thus, this study presents a viable ORR catalyst with high activity and long-term stability for bio-electricity generation from organic wastewater in SC-MFCs.

Background H2–ethanol-coproducing bacteria, as primary fermenters, play important roles in the microbiome of bioreactors for bioenergy production from organic wastewater or solid wastes. Ethanoligenens harbinense YUAN-3 is an anaerobic ethanol–H2-fermenting bacterium. Ethanol is one of the main end-products of strain YUAN-3 that influence its fermentative process. Until recently, the molecular mechanism of metabolic regulation in strain YUAN-3 during ethanol accumulation has still been unclear. This study aims to elucidate the metabolic regulation mechanisms in strain YUAN-3, which contributes to effectively shape the microbiome for biofuel and bioenergy production from waste stream. Results This study reports that ethanol stress altered the distribution of end-product yields in the H2–ethanol-coproducing Ethanoligenens harbinense strain YUAN-3. Decreasing trends of hydrogen yield from 1888.6 ± 45.8 to 837 ± 64.7 mL L−1 and acetic acid yield from 1767.7 ± 45 to 160.6 ± 44.7 mg L−1 were observed in strain YUAN-3 with increasing exogenous ethanol (0 mM–200 mM). However, the ethanol yield of strain YUAN-3 increased by 15.1%, 30.1%, and 27.4% in 50 mM, 100 mM, and 200 mM ethanol stress, respectively. The endogenous ethanol accounted for 96.1% (w/w) in liquid end-products when exogenous ethanol of 200 mM was added. The molar ratio of ethanol to acetic acid increased 14 times (exogenous ethanol of 200 mM) compared to the control. iTRAQ-based quantitative proteomic analysis indicated that 263 proteins of strain YUAN-3 were differentially expressed in 50 mM, 100 mM, and 200 mM of exogenous ethanol. These proteins are mainly involved in amino acid transport and metabolism, central carbon metabolism, and oxidative stress response. Conclusion These differentially expressed proteins play important roles in metabolic changes necessary for growth and survival of strain YUAN-3 during ethanol stress. The up-regulation of bifunctional acetaldehyde-CoA/alcohol dehydrogenase (ADHE) was the main reason why ethanol production was enhanced, while hydrogen gas and acetic acid yields declined in strain YUAN-3 during ethanol stress. This study also provides a new approach for the enhancement of ethanologenesis by H2–ethanol-coproducing bacteria through exogenous ethanol addition.

Glucose and xylose co-fermentation is crucial to maximize hydrogen yield from waste lignocellulose. In this study, cell growth, sugar consumption, and hydrogen production profiles of Thermoanaerobacter thermosaccharolyticum W16 feeding with a range of glucose and xylose were experimental investigated coupled with kinetic analysis. Results showed although T. thermosaccharolyticum W16 could use both glucose and xylose for hydrogen production, a maximum cell growth rate of 0.27 g/L/h and hydrogen production rate of 14.53 mmol/L/h was found with glucose as sole substrate, the value was 92.8% and 49.8% higher than using xylose as the only carbon source. Further interpolation analysis and experimental demonstration suggested when glucose content in the mixed substrate higher than 58.2%, the inhibitory effect on xylose utilization was increased, but when glucose concentration fell below 21.7%, its utilization will be subject to a certain degree of feedback inhibition. Coupling experimental results with kinetic analysis in this study provides a powerful evidence to further develop the potential of T. thermosaccharolyticum W16 as a biocatalyst for hydrogen production from lignocellulosic biomass.

In the present work, with corn stover hydrolysate as the substrate, an efficient hydrogen-producing thermophile, Thermoanaerobacterium thermosaccharolyticum W16, was added to three kinds of seed sludge (rotten corn stover (RCS), cow dung compost (CDC), and sludge from anaerobic digestion (SAD)) to investigate the effect of bioaugmentation on thermophilic hydrogen production. Batch test results indicate that the bioaugmentation with a small amount of the strain T. thermosaccharolyticum W16 (5% of total microbes) increased the hydrogen yield to varying degrees (RCS: from 8.78 to 9.90 mmol H2/g utilized sugar; CDC: from 8.18 to 8.42 mmol H2/g utilized sugar; SAD: from 8.55 to 9.17 mmol H2/g utilized sugar). The bioaugmentation process also influenced the soluble metabolites composition towards more acetate and less butyrate production for RCS, and more acetate and less ethanol accumulation for SAD. Microbial community analysis indicates that Thermoanaerobacterium spp. and Clostridium spp. dominated microbial community in all situations and might be mainly responsible for thermophilic hydrogen generation. For RCS and SAD, the bioaugmentation obviously increased the relative abundance of the strain T. thermosaccharolyticum W16 in microbial community, which might be the main reason for the improvement of hydrogen production in these cases.

The synergies between transition metal oxides (bimetallic oxides) play important roles in determining the bifunctional catalytic activity for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline media. This study uses a facile hydrothermal method for uniformly coating CeO2 shells on the surfaces of ZIF-67-derived porous Co3O4@Z67-NT (T-temperature, 500–900 °C) cores. Co3O4@Z67-N700@CeO2 exhibits excellent bifunctional (ORR/OER) catalytic activity with a ΔE [Ej=10(OER) − E1/2(ORR)] of 0.70 V. For ORR, Co3O4@Z67-N700@CeO2 exhibits a higher half-wave potential of 0.88 V (vs. RHE) than that of commercial Pt/C (0.87 V), which is attributed to the synergies between CeO2 (Ce3+) and Co3O4 (Co2+). The oxygen vacancies on CeO2 can enhance O2 adsorption on the interfaces to promote the activation of adsorbed O2 to O2−, and can alleviate O2 deficiency during ORR, thereby improving ORR activity. For OER, Co3O4@Z67-N700@CeO2 has a lower overpotential of 350 mV at 10 mA cm−2 and a higher Faraday efficiency of 92.2% than those of RuO2. An effective valence transition between Ce3+ and Ce4+ endows CeO2 with high electrical conductivity and oxygen storage capacity, which greatly promote charge transfer and the generation/smooth transport of highly active species (O22−/O−). Moreover, the interactions between CeO2 (Ce3+/Ce4+ and oxygen vacancies) and Co3O4 (Co3+/CoOOH) provide more electrochemically active sites for OER. This study provides a new strategy for constructing the stable core@shell structure based on MOF derivatives to improve the ORR/OER performance.

The lipid production and nutrients removal of Scenedesmus sp. in non-sterile domestic wastewater were investigated in the present study. Compared with secondary effluent, primary effluent was more appropriate substrate for algal growth, and the biomass concentration and lipid yield reached 0.69 ± 0.02 g L−1 and 166.7 ± 8.3 mg L−1, respectively. Ultrasonic exposure significantly enhanced the lipid yield and wastewater treatment performance. The biomass and lipid accumulation increased to 1.56 ± 0.07 g L−1 and 240 ± 9.2 mg L−1 at the optimum ultrasonic treatment frequency of 18 Hz, power of 20 W and time of 10 min. The maximum TN and TP removal rates reached 96.8% and 97.7%, respectively. Microbial community analysis revealed that the ultrasonic treatment markedly affected the microbial communities, which can accelerate the formation of favorable microbial community structure. Gemmobacter and Porphyrobacter were identified as key bacteria under ultrasonic condition, and their relative abundances were 38.7% and 19.1%, respectively. This research showed the efficiency of ultrasonic treatment in promoting algal lipid yield and domestic wastewater treatment.

In this study, an innovative approach was proposed based on the implement of biochar derived from residue cornstalk left after anaerobic bio-hydrogen production (RCA-biochar) to improve direct bio-hydrogen production from anaerobic fermentation of cornstalk. The bio-hydrogen production potential and maximum bio-hydrogen production rate increased from 156.2 to 286.1 mL H2/g substrate and 3.5 to 5.7 mL H2/g substrate/h, respectively, following the added RCA-biochar increased from 2.5 to 15.0 g/L. Cornstalk chemical component analysis showed the cellulose and hemicellulose content decreased by 17.9–33.7% and 14.4–25.2%, and lignin content increased by 20.3–42.8%, respectively, after 96 h anaerobic fermentation with RCA-biochar 2.5–15.0 g/L. Further analyses revealed that RCA-biochar not only provided more specific surface area for hydrogen-producing bacteria attachment, but also promoted the cellulolytic enzyme activity, thereby resulted in increased substrate conversion to bio-hydrogen. The findings obtained in this study may provide supports for effective and sustainable lignocellulosic bio-hydrogen production in the future.

To reduce start-up time and enhance hydrogen production efficiency, a sequential immobilization and deoxygenization (SIDO) strategy for hydrogen production was investigated in continuous-flow moving bed biofilm reactors (MBBRs). The pre-immobilization process accelerated the initial enrichment of hydrogen-producing bacteria (HPB) and promoted the biofilm formation, which contribute to higher hydrogen production efficiency in SIDO-MBBRs compared to a non-immobilized reactor. A similar deoxygenization effect was achieved by inoculation with Pseudomonas aeruginosa compared with N2 sparging, and the P. aeruginosa pre-immobilized MBBR (Pse-MBBR) showed a higher H2 yield in the initial stage of operation. Microbial community analysis found a higher abundance of putative HPB in the range of 82.82-96.56%, with the predominant populations in the SIDO-MBBR assigned to genera Clostridium and Enterobacter. The results suggest that the SIDO-MBBR is an effective approach for rapid recruitment of HPB and start-up of fermentative hydrogen production.

Background Ethanol-type fermentation, one of the fermentation types in mixed cultures of acidogenesis with obvious advantages such as low pH tolerance and high efficiency of H2 production, has attracted widespread attentions. pH level greatly influences the establishment of the fermentation of carbohydrate acidogenesis by shaping community assembly and the metabolic activity of keystone populations. To explore the adaptation mechanisms of ethanol-type fermentation to low pH, we report the effects of initial pH on the physiological metabolism and transcriptomes of Ethanoligenens harbinense—a representative species of ethanol-type fermentation. Results Different initial pH levels significantly changed the cell growth and fermentation products of E. harbinense. Using transcriptomic analysis, we identified and functionally categorized 1753 differentially expressed genes (DEGs). By mining information on metabolic pathways, we probed the transcriptional regulation of ethanol–H2 metabolism relating to pH responses. Multiple pathways of E. harbinense were co-regulated by changing gene expression patterns. Low initial pH down-regulated the expression of cell growth- and acidogenesis-related genes but did not affect the expression of H2 evolution-related hydrogenase and ferredoxin genes. High pH down-regulated the expression of H2 evolution- and acidogenesis-related genes. Multiple resistance mechanisms, including chemotaxis, the phosphotransferase system (PTS), and the antioxidant system, were regulated at the transcriptional level under pH stress. Conclusions Ethanoligenens adapted to low pH by regulating the gene expression networks of cell growth, basic metabolism, chemotaxis and resistance but not H2 evolution-related genes. Regulation based on pH shifts can represent an important approach to establish and enhance ethanol-type fermentation. The complete gene expression network of ethanol fermentative bacteria for pH response provides valuable insights into the acidogenic fermentation, and offers an effective regulation strategy for the sustainable energy recovery from wastewater and solid waste.

Micro-aeration is an effective tool that helps integrated autotrophic and heterotrophic denitrification process to withstand high sulfide concentration by making heterotrophic sulfide-oxidizing nitrate-reducing bacteria (h-soNRB) prevail. For further understanding of the dominance of h-soNRB, Pseudomonas C27 was selected as the typical bacterium and its metabolic characteristics responding to sulfide and oxygen stimulation were studied. Under high sulfide concentration condition, addition of trace oxygen led to a two-stage sulfide oxidation process, and sulfide oxidation rate in the first stage was 1.4 times more than that under anaerobic condition. According to transcriptome analysis, the pdo gene significantly up-regulated 2.36 and 2.57 times with and without oxygen under stimulation of high sulfide concentration. Additionally, two possible enhanced sulfide removal pathways coping with high sulfide concentration, namely sqr-cysI-gpx-gor-glpE and cysK-gshA-gshB-pdo-glpE, caused by oxygen were proposed in Pseudomonas C27. These findings provide a theoretical basis for locating high-efficiency sulfur oxidase in h-soNRB.

The metabolic function and organic degradation behavior of bacterial and fungal communities were detected in 60 days composting of chicken manure and pumice by using Biolog tools, PICRUSt and FUNGuild. Fungal diversity increased from 57 OTUs in fresh chicken manure to 109 OTUs in high temperature stage, while bacterial diversity decreased from 86 OTUs to 44 OTUs after composting treatment. The carbohydrates degradation ability of bacterial community was enhanced in the high temperature stage. Fungal community had relatively higher degradation rates of carboxylic acids and amino acids in the maturation stage. Saprotroph was the main trophic mode of fungal community during the incubation process. The fungal animal pathogen decreased from 12.5% to 1.2% after composting treatment. Bacterial community composition and substrates degradation rate were mainly influenced by redox potential, pH and moisture, while temperature was the main environmental factor influencing on organic degradation of fungal community.

Lignocellulose has been considered a potential feedstock for biohydrogen production. Recently, a novel closed-loop concept of biochar approach was developed for enhanced lignocellulosic biohydrogen production. This study therefore targets to analyze the environmental impacts of the three existing lignocellulosic biohydrogen production processes, and evaluate the environmental performance of applying biochar in each process at this early stage of technological development. The results suggest that biochar dosing shows better environmental performance for all impact categories, especially in the consolidate bioprocessing case. Electricity consumption was found to be the dominant cause of environmental impact over the life cycle, while by-products generation was also found to have an effect on the life-cycle impacts. Future research focuses on the biohydrogen production scale, the electricity generation scheme transition towards renewable and cleaner energetic systems, and recovery the by-products to the maximum extent, that will make lignocellulosic biohydrogen production more environmentally sustainable.

Succession of bacterial community, metabolism function and substrate utilization capacity in 60 days composting of cow manure were analyzed by 16S rRNA pyrosequencing, PICRUSt and Biolog method, respectively. The results showed that the number of bacterial OTUs increased from 176 in raw cow manure to 203 on Day-10, 220 on Day-30 and 313 on Day-60 of the composting, respectively. The PICRUSt analysis showed that the relative abundances of genes involved in lipid and carbohydrate metabolism increased by 28.5% and 22.4% during the incubation, respectively, but the abundances of the genes involved in nucleotide and amino acid metabolism decreased by 21.6% and 2.1%. Furthermore, the average well color development (AWCD) of carboxylic acids (0.99–0.48) and amino acids (1.61–0.89) in Biolog Eco-microplate displayed a steady downtrend through the composting process. Redundancy analysis showed that ORP, moisture and temperature could explain 68.1%, 17.6% and 14.2% of the variation in bacterial genera, respectively.

Sludge generated from wastewater treatment plants causes severe environmental problems, which can be significantly reduced using anaerobic digestion. However, CO2, anaerobic digestate, and the residues from anaerobic digestion process still need to be treated. Accordingly, some energy-rich microalgae can grow well in sludge digestate contained wastewater, which enhances its economic feasibility for biofuel production. Therefore, in this review, the integration of sludge digestion and microalgal cultivation is proposed for enhancing the performance of bioenergy and biorefinery industries. Microalgae can simultaneously utilize sludge digestate and CO2 as the carbon sources for biofuel production and biogas upgradation. This comprehensive review mainly analyzes different compositions of anaerobic digestate, sludge pretreatment methods, favorable environmental factors, and different CO2 concentrations, which influence the growth of microalgae and the accumulation of bioenergy. Finally, the waste residues from sludge digestion and microalgae cultivation are converted to bio-gas, bio-oil, and biochar, which can be used as biofuels, supercapacitors, adsorbents, and catalysts through thermal conversion. This review indicates that the pyrolysis process has a positive net energy production and hydrothermal treatment can be chosen as the wet biomass conversion method. The aim of this review is to provide useful information for combining the sludge digestion and microalgal cultivation to simultaneously reduce the pollutants and produce bioenergy.

Electro-dewatering (ED) pretreatment could improve sludge dewatering performance and remove heavy metal, but the effect of ED pretreatment on nitrous oxide (N2O) emission and related functional genes in sludge composting process is still unknown, which was firstly investigated in this study. The results revealed that ED pretreatment changed the physicochemical characteristics of sludge and impacted N2O related functional genes, resulting in the reduction of cumulative N2O emission by 77.04% during 60 days composting. The higher pH and NH4+-N, but lower moisture, ORP and NO2−-N emerged in the composting of ED sludge compared to mechanical dewatering (MD) sludge. Furthermore, ED pretreatment reduced amoA, hao, narG, nirK and nosZ in ED sludge on Day-10 and Day-60 of composting. It was found that nirK reduction was the major factor impacting N2O generation in the initial composting of ED sludge, and the decline of amoA restricted N2O production in the curing period.

An increasing interest is devoted to combined microbial electrolysis cell-anaerobic digestion (MEC-AD) system which could convert waste activated sludge into biogas. In this study series tests were initially conducted to study the effect of alkaline pretreatment on AD system and the results showed that alkaline pretreatment could promote the dissolution of organic matters in the sludge and thus improve the methane production. Then, the methane production in combined MEC-AD system fed with alkaline-pretreated sludge was investigated. The results indicated that the methane productions increased by 37% and 42% when applied voltage was 0.5 V and 0.8 V. The microbial electrochemical system strongly promoted the growth of Euryarchaeota (Methanosaeta and Methanobacterium). Meanwhile, the abundance of Paraclostridium increased from 17.9% to 38.5% when applied voltage was 0.8 V, suggesting an enhanced fermentation and acetogenesis process. The results of energy balance estimation indicated that MEC-AD system at 0.5 V could achieve higher net energy output.

Biochar is known to efficiently adsorb dyes from wastewater. In this study, biochar was derived from macroalgae residue by pyrolysis, and the influence of varying temperature (from 400 °C to 800 °C) on biochar characteristics was investigated. Among the biochar samples tested, macroalgae-derived biochar possessing highly porous structure, special surface chemical behavior and high thermal stability was found to be efficient in removing malachite green, crystal violet and Congo red. The biochar derived by pyrolysis at 800 °C showed the highest adsorption capacity for malachite green (5306.2 mg g−1). In this study, the transformation of microalgae residue into a highly efficient dye adsorbent is a promising procedure for economic and environmental protection.

A coupled system of dark fermentation and microalgal cultivation was applied to investigate the hydrogen and lipid production potentials from three main substrates of food waste. Compared with waste proteins and waste fats, waste carbohydrates were more appropriate for energy production, which exhibited the highest cumulative hydrogen volume of 668.3 ± 36.5 mL L−1 and hydrogen yield of 133.66 ± 7.31 mL g−1 substrate. Most by-products of dark fermentation were consumed in algal culture process, and the maximum lipid content and lipid productivity reached 33.2 ± 1.8% and 52.6 ± 1.1 mg L−1 d−1, respectively. The energy conversion efficiency significantly enhanced from 10.14% (dark fermentation) to 24.06% (coupled system). In continuous operation, energy production was steady and efficient, and the average hydrogen production rate of 741.4 mL L−1 d−1 and average lipid concentration of 0.4 g L−1 were obtained. This study provides a promising and sustainable route for efficient energy recovery from waste substrates by using coupled hydrogen and lipid production system in long-term operation.

Microbial electrolysis cells (MECs) are an efficient technology for generating hydrogen gas from organic matters, but an additional voltage is needed to overcome the thermodynamic barrier of the reaction. A combined system of MEC and the aluminum-air battery (Al-air battery) was designed for hydrogen generation, coagulant production and operated in an energy self-sufficient mode. The Al-air battery (28 mL) produced a voltage ranged from 0.58 V to 0.80 V, which powered an MEC (28 mL) to produce hydrogen. The hydrogen production rate reached 0.19 ± 0.01 m3 H2/m3/d and 14.5 ± 0.9 mmol H2/g COD. The total COD removal rate was 85 ± 1%, of which MEC obtained 75 ± 1% COD removal and 10 ± 1% COD removal was achieved by in-situ coagulating process. The microorganisms removal of MEC effluent was 97 ± 2% through ex-situ coagulating process. These results showed that the Al-air battery-MEC system can be operated in energy self-sufficient mode and recovered energy from wastewater with high quality effluent.

The properties of biochar derived from waste activated sludge and anaerobic digestion sludge under pyrolysis temperature varying from 400°C to 800°C were investigated. The heavy metals adsorption efficiency of the sludge-derived biochar was also examined. Among the biochar samples tested, ADSBC600 possessing highly porous structure, special surface chemical behaviors and high thermal stability was found to remove Pb2+ from aqueous solutions efficiently with an adsorption capacity of 51.20mg/g. The Pb2+ adsorption kinetics and isotherm for ADSBC600 can be described using the pseudo second-order model and Langmuir isotherm, respectively. Analysis of the characteristics of biochar before and after metal treatment suggests that electrostatic attraction, precipitation, surface complexation and ion exchange are the possible Pb2+ removal mechanisms. This study demonstrates a successful example of waste refinery by converting anaerobic digestion sludge to feasible heavy metal adsorbents to implement the concept of circular economy.

Lignocellulosic crop wastes (LCW) are refractory solid wastes that are not biodegradable at appreciable rates in most environments, causing management of LCW been environmental concerns for years. This study investigated the feasibility of low waste emission complete LCW (rice straw (RS), rice husk (RH), and corn straw (CS)) recycling through feeding to Tenebrio molitor Linnaeus larvae (mealworms) using egested frass to produce organic fertilizers. For larvae fed RS, CS, and RH plus nutrients co-diets groups, the 48-day average specific rates of LCW consumption increased by 118.09%, 155.30%, and 87.14%, respectively when compared with that of sole diet groups. The order of the feed consumption rate and conversion rate in a mealworm farm fed on the three LCWs agreed with the trend obtained with lab-scale experiments, with RS＞CS＞RH. The forty-eight days cellulose, hemicellulose, and lignin biodegradation increased by 1.48–17.61%, 4.26–11.50%, and 4.20–15.75%, respectively, for co-fed larvae. Enterococcus sp. and Erwinia sp., which previous reports have indicated are strongly associated with lignocellulose degradation, were identified in the gut microbiome of mealworms fed with RS and CS co-diets. Furthermore, the RS-fed frass quickly formed a high-quality compost within 32 days of composting, which had a germination rate ratio of 8% and 17% higher than that of WB and CS-fed frass. LCA (life cycle assessment) proved a relatively promising environmental-friendly alternative to dispose of RS, using their excreted frass for composting with low waste emissions. This study provides new insight into insect-involved crop waste utilization, and economical strategies for sustainable in situ recycling of LCWs into high-value-added products.

Anaerobic co-digestion of a cow manure-cotton straw mixture (CCM) has been shown to promote methanogenesis, but the recalcitrant crystal structure of organic polymers in CCM hinders its hydrolysis during anaerobic digestion (AD). Here, the efficacy of different pretreatment methods based on potassium ferrate (PF) and peroxymonosulfate (PMS) was evaluated to facilitate CCM decomposition and methanogenesis during AD. The maximum lignocellulosic removal rate (62.5%), the highest volatile fatty acids (VFAs) (7769.6 mg/L), and cumulative methane yield (109.4 mL CH4/g VS) were both achieved in PF-pretreated samples after the digestion process. The dominant bacterial populations in PF-pretreated CCM were affiliated with Sideroxydans, Herbinix, Clostridium, and Smithella, which played an important role in the hydrolysis and acidification of CCM. The enrichment of Methanosarcina and Methanobacterium and highly-effective acidogenesis might account for the highest methane yield in the PF-pretreated group.

Increasing the environmental sustainability of wastewater treatment contributes to the construction of sustainable urban water systems, especially for developing countries. Life cycle assessments (LCA) have quantified the environmental implications of overly-sophisticated discharge standards. However, studies on these topics provide limited practical guidance, as real policy concerns are rarely incorporated in the assessment process. One such concern is watershed management by satisfying the water quality limit (WQL) of the receiving environment. To manage sustainable wastewater treatment from a watershed perspective, this study integrates LCA with water quality models to facilitate the decision process. By parameterizing the WQL as a constraint condition, a hierarchical priority structure is established in the environmental index system, and alternatives that satisfy the WQL are screened, and compared in terms of life cycle burdens. This study investigates the effect of considering WQL on the evaluation of wastewater treatment strategies, using an urban sewage system case study in China. In wastewater treatment plants (WWTPs), determining discharge levels based on the WQL of the receiving river, contributes to specific control of WWTPs with reduced life cycle burdens, compared with the “one size fits all” administrative strategy. Considering the influence of non-point source pollution (urban runoff), results demonstrate that only relying on wastewater treatment is unlikely to reliably satisfy the WQL. This study highlights the importance of utilizing an integrated policy to coordinate the treatment of wastewater and urban runoff for watershed management, by coupling enhanced wastewater treatment intensities with the green and gray storm water management infrastructures. This integrated policy quantitatively showed advantages in terms of stable control of water pollution, and less dependence on the self-purification capacity of the receiving river.

In this work, a green, cost-saving and energy-saving chemical was produced to dehydrate and detoxify sludge. Variations of chemical properties, and its effects on co-removal of bound water, organics and risky toxic elements (including Cd, Crtotal, Cu, Pb, Zn, Ni and As) from sludge were investigated. Results showed that potential distribution was a key aspect of sludge reduction and detoxification. Cationic chemical could release almost 86% of bound water from sludge through producing potential difference and re-aggregating sludge flocs. Proteins reduction could largely remove organics with molecular weight between 3.5 × 103 to 7.5 × 103 Da, and moreover, humic acids were highly effective on toxic elements removal due to its ion exchange, chelation and complexation on it. Thus, variations of proteins and humic acids can reflect the distribution of organics and elements in sludge. Approximately 73% of organics was removed in flocculation process, and additionally, 54% of risky toxic elements was removed through chelating process and flocs sweeping, weakening its ecological risk by 53.71%. Comparing with the commonly used cationic polyacrylamide, the product can save 38.05–40.64% of electric energy in releasing per-unit bound water, and also can acquire much more environmental benefit at unit cost. This further suggested that chemical addition was a clean and environmentally sustainable way for sludge reduction and detoxification.

Biochar derived from residue cornstalk left after anaerobic bio-hydrogen production (RCA-biochar) was confirmed to enhance bio-hydrogen production from cornstalk hydrolysate. However, the role of RCA-biochar in simultaneous saccharification and fermentation (SSF) during bio-hydrogen production from cornstalk has not yet been revealed. This study therefore aims to fill this knowledge gap. It was observed that with the increase in RCA-biochar concentration from 0 g/L to 10.0 g/L, the maximal cumulative SSF bio-hydrogen yield varied from 24.3 ± 1.1 mL/g-substrate to 154.3 ± 3.6 mL/g substrate under varying pH values – 5.5, 6.0, 6.5, 7.0. The increasing bio-hydrogen production was observed to correlate with both RCA-biochar level and initial pH. Batch tests confirmed that the initial pH had an obvious effect an saccharification, while RCA-biochar affected anaerobic fermentation a lot. The findings revealed the role of previously unrecognized RCA-biochar in SSF bio-hydrogen production from cornstalk, which can provide an alternative approach for lignocellulosic bio-hydrogen production.

This study aims at evaluating the performance and microbial community dynamics of anaerobic membrane bioreactor (AnMBR) treating antibiotic solvent wastewater at improved influent quality period. The whole process was divided into five phases according to the influent COD concentration with a fluctuated volume loading rate (VLR) ranging from 3.9 to 12.7 kg COD/(m 3 ·d). After 249 days of operation, the average COD and THF removal efficiency were 93.6% and 98.7%, respectively. The accumulation of VFA, relatively low pH, decline of biogas production and methane content were discovered at higher VLR (>10 kg COD/(m 3 ·d)). Methanomicrobiales are the major population throughout the whole running period. Methanosaetaceae showed a minor relative abundance compared both of them, while Methanobacteriales remained a minimum value. Results showed that the reactor performed an excellent pollutants removal effect because of the function of membranes even at high VLR conditions.

Background The light/dark cycle is one of the most important factors affecting the microalgal growth and lipid accumulation. Biomass concentration and lipid productivity could be enhanced by optimization of light/dark cycles, and this is considered an effective control strategy for microalgal cultivation. Currently, most research on effects of light/dark cycles on algae is carried out under autotrophic conditions and little information is about the effects under mixotrophic cultivation. At the same time, many studies related to mixotrophic cultivation of microalgal strains, even at large scale, have been performed to obtain satisfactory biomass and lipid production. Therefore, it is necessary to investigate cellular metabolism under autotrophic and mixotrophic conditions at different light/dark cycles. Even though microalgal lipid production under optimal environmental factors has been reported by some researchers, the light/dark cycle and temperature are regarded as separate parameters in their studies. In practical cases, light/dark cycling and temperature variation during the day occur simultaneously. Therefore, studies about the combined effects of light/dark cycles and temperature variation on microalgal lipid production are of practical value, potentially providing significant guidelines for large-scale microalgal cultivation under natural conditions. Results In this work, cell growth and lipid accumulation of an oleaginous microalgal mutant, Scenedesmus sp. Z-4, were investigated at five light/dark cycles (0 h/24 h, 8 h/16 h, 12 h/12 h, 16 h/8 h, and 24 h/0 h) in batch culture. The results showed that the optimal light/dark cycle was 12 h/12 h, when maximum lipid productivity rates of 56.8 and 182.6 mg L−1 day−1 were obtained under autotrophic and mixotrophic cultivation, respectively. Poor microalgal growth and lipid accumulation appeared in the light/dark cycles of 0 h/24 h and 24 h/0 h under autotrophic condition. Prolonging the light duration was unfavorable to the production of chlorophyll a and b, which was mainly due to photooxidation effect. Polysaccharide was converted into lipid and protein when the light irradiation time increased from 0 to 12 h; however, further increasing irradiation time had a negative effect on lipid accumulation. Due to the dependence of autotrophically cultured cells on light energy, the light/dark cycle has a more remarkable influence on cellular metabolism under autotrophic conditions. Furthermore, the combined effects of temperature variation and light/dark cycle of 12 h/12 h on cell growth and lipid accumulation of microalgal mutant Z-4 were investigated under mixotrophic cultivation, and the results showed that biomass was mainly produced at higher temperatures during the day, and a portion of biomass was converted into lipid under dark condition. Conclusions The extension of irradiation time was beneficial to biomass accumulation, but not in favor of lipid production. Even though effects of light/dark cycles on autotrophic and mixotrophic cells were not exactly the same, the optimal lipid productivities of Scenedesmus sp. Z-4 under both cultivation conditions were achieved at the light/dark of 12 h/12 h. This may be attributed to its long-term acclimation in natural environment. By combining temperature variation with optimal light/dark cycle of 12 h/12 h, this study will be of great significance for practical microalgae-biodiesel production in the outdoor conditions. Electronic supplementary material The online version of this article (10.1186/s13068-017-0948-0) contains supplementary material, which is available to authorized users.

Mycelia pellets were employed as biological carrier in a continuous stirred tank reactor to reduce biomass washout and enhance hydrogen production from cornstalk hydrolysate. Hydraulic retention time (HRT) and influent substrate concentration played critical roles on hydrogen production of the bioreactor. The maximum hydrogen production rate of 14.2 mmol H 2 L −1 h −1 was obtained at optimized HRT of 6 h and influent concentration of 20 g/L, 2.6 times higher than the counterpart without mycelia pellets. With excellent immobilization ability, biomass accumulated in the reactor and reached 1.6 g/L under the optimum conditions. Upon further energy conversion analysis, continuous hydrogen production with mycelia pellets gave the maximum energy conversion efficiency of 17.8%. These results indicate mycelia pellet is an ideal biological carrier to improve biomass retention capacity of the reactor and enhance hydrogen recovery efficiency from lignocellulosic biomass, and meanwhile provides a new direction for economic and efficient hydrogen production process.

Biochars derived from three microalgal strains (namely, Chlorella sp. Cha-01, Chlamydomonas sp. Tai-03 and Coelastrum sp. Pte-15) were evaluated for their capacity to adsorb p-nitrophenols (PNP) using raw microalgal biomass and powdered activated carbon (PAC) as the control. The results show that BC-Cha-01 (biochar from Chlorella sp. Cha-01) exhibited a high PNP adsorption capacity of 204.8mgg-1, which is 250% and 140% higher than that of its raw biomass and PAC, respectively. The adsorption kinetics and equilibrium are well described with pseudo-second-order equation and Freundlich model, respectively. BC-Cha-01 was found to contain higher polarity moieties with more O-containing functional groups than PAC and other microalgae-derived biochars. The strong polarity of binding sites on BC-Cha-01 may be responsible for its superior adsorption capacity. The biochars from Chlorella sp. Cha-01 seem to have the potential to serve as a highly efficient PNP adsorbent for wastewater treatment or emergency water pollution control.

In this study, a carbohydrate-rich microalga Neochloris aquatica CL-M1 was adapted to grow in swine wastewater. The effects of cultivation conditions (i.e., temperature, light intensity or N/P ratio) on COD/nutrients removal and carbohydrate-rich biomass production were investigated. The results indicate that the highest COD removal (81.7%) and NH3-N removal (96.2%) was achieved at 150 µmol m−2 s−1 light intensity, 25 °C and N/P ratio = 1.5/1. The highest biomass concentration and carbohydrate content was 6.10 g L−1 and 50.46%, respectively, when N/P ratio = 5/1. The resulting carbohydrate-rich microalgal biomass was pretreated and used as a feedstock for butanol fermentation. With the initial sugar concentration of 48.7 g L−1 glucose and 3.4 g L−1 xylose in the pretreated biomass, the butanol concentration, yield, and productivity were 12.0 g L−1, 0.60 mol mol−1 sugar, and 0.89 g L−1 h−1, respectively, indicating the high potential of using Neochloris aquatica CL-M1 for butanol fermentation.

For deeply understanding the H 2 production promotion mechanism by adding Mg 2+ and Fe 2+ in Ethanoligenens harbinense fermentation process, the effects on cell growth, liquid byproducts production and H 2 yield at growth level were investigated, meanwhile the expressions of [FeFe]-hydrogenase, acetate kinase, alcohol dehydrogenase and lactate dehydrogenase with quantitative reverse transcription PCR at transcript level were monitored. The experimental results indicated that Mg 2+ makes more contributions on cell growth, but with Mg 2+ concentration increasing the expressions of functional genes were obviously suppressed. Fe 2+ has slightly positive effects on increasing cell growth and functional genes expression, which is inferred the reason of H 2 production enhancement. A maximum hydrogen yield of 2.14 mol-H 2 /mol-glucose was obtained in optimal medium supplemented with 600 mg/l MgCl 2 ·6H 2 O and 100 mg/l FeSO 4 ·7H 2 O. The realization of hydrogen production enhancement of E. harbinense by adding promoting factors was not only realized through increasing cell biomass growth and hydrogenase activity, but also some promotion effects on functional enzyme genes expressions.

In order to strengthen photo-fermentative hydrogen production by different photocatalytic nanoparticles, hydrogen production by photo-fermentative bacteria with addition of TiO 2 , ZnO and SiC nanoparticles in batch culture were investigated in this study. The results indicated that three nanoparticles could improve hydrogen production performance of Rhodopseudomonas sp. nov. strain A7 under respective optimal conditions. The hydrogen yield of 2.81 mol-H 2 /mol-acetate was obtained when TiO 2 nanoparticles with a concentration of 300 mg/L and size of 25 nm. The concentration of ZnO nanoparticles was at 100 mg/L, hydrogen yield reached 2.64 mol-H 2 /mol-acetate. Compared with TiO 2 and ZnO nanoparticles, SiC nanoparticles exhibited greatest potential for enhancing photo-hydrogen production. By addition of nano-SiC with concentration of 200 mg/L which was prepared at temperature of 1500 °C, the maximum hydrogen volume, average hydrogen content and hydrogen yield of strain A7 were achieved at 2272 mL-H 2 /L-culture, 85.2% and 2.99 mol-H 2 /mol-acetate, respectively. And hydrogen production was 18.6% higher than that of alone strain A7 without the addition of nanoparticles. Therefore, the addition of SiC nanoparticles is a promising strategy to improve photo-fermentative hydrogen production from wastewater.

To achieve stable and efficient photo-fermentative hydrogen production, this work investigated photo-fermentative hydrogen production by forming biofilm on the surface of carrier in the biofilm reactor (BR). Results showed the hydrogen production performance was greatly improved by formed biofilm. The time of hydrogen production and efficiency of substrate utilization were enhanced obviously compared to the control reactor (CR). When the CR was used, hydrogen production stopped at 7th day and maximum cumulative hydrogen volume and hydrogen yield were 1730 ± 87 mL/L and 1.44 ± 0.07 mol H 2 /mol acetate, respectively. However, in the BR hydrogen production volume of 3028 ± 150 mL/L and hydrogen yield of 2.52 ± 0.13 mol H 2 /mol acetate were obtained, which were enhanced about 75% compared to that of the CR. The time of hydrogen production extended from 7 days of CR to 12 days of BR and the substrate conversion efficiency increased from 36% of CR to 63% of BR. It was worth noting at 8th day that substrate was almost utilized completely but hydrogen production still lasted for 4 days. This suggested that the formation of biofilm in BR was favorable to continuous hydrogen production and substrate utilization with high efficiency. Results demonstrated the BR can get a more stable and consistent operating process and it was a proper and potential way to produce hydrogen by photo-fermentative bacteria (PFB).

Background Simultaneous wastewater treatment and lipid production by oleaginous microalgae show great potential to alleviate energy shortage and environmental pollution, because they exhibit tremendous advantages over traditional activated sludge. Currently, most research on wastewater treatment by microalgal are carried out at optimized temperature conditions (25–35 °C), but no information about simultaneous wastewater treatment and lipid production by microalgae at low temperatures has been reported. Microalgal growth and metabolism will be inhibited at low temperature conditions, and satisfactory wastewater treatment performance will be not obtained. Therefore, it is critical to domesticate and screen superior microalgal strains with low temperature adaptability, which is of great importance for wastewater treatment and biodiesel production. Results In this work, simultaneous wastewater treatment and lipid production were achieved by a microalgal mutant Scenedesmus sp. Z-4 at the low temperature conditions (4, 10, and 15 °C). The results showed that algal growth was inhibited at 4, 10, and 15 °C compared to that at the optimal temperature of 25 °C. However, decreased temperature had no significant effect on the total cellular lipid content of algae. Importantly, lipid productivity at 10 °C was compromised by more net energy output relevant to biodiesel production, which demonstrated that the low temperature of 10 °C was favorable to wastewater treatment and energy recovery by Scenedesmus sp. Z-4. When molasses wastewater with optimal COD concentration of 8000 mg L−1, initial inoculation ratio of 15%, and C/N ratio of 15 was used to cultivate microalgae, the maximum removal rate of COD, TN, and TP at 10 °C reached 87.2, 90.5, and 88.6%, respectively. In addition, lipid content of 28.9% and lipid productivity of 94.4 mg L−1 day−1 were obtained. Conclusions Scenedesmus sp. Z-4 had good adaptability to low temperature conditions, and showed great potential to realize simultaneous wastewater treatment and lipid production at low temperatures. The proposed approach in the study was simple compared to other wastewater treatment methods, and this potential novel process was still efficient to remove COD, N, and P at low temperatures. Thus, it had a vital significance for the wastewater treatment in low temperature regions.