scholarly journals Pretreatments for enhancing sewage sludge reduction and reuse in lipid production

2020 ◽  
Author(s):  
Jiaxin Chen ◽  
Ji Li ◽  
Xiaolei Zhang ◽  
Zhaoyang Wu
Keyword(s):  
Lipid Content ◽  
Solid Phase ◽  
Lipid Production ◽  
Oxygen Demand ◽  
Rhodotorula Glutinis ◽  
Wastewater Sludge ◽  
Sludge Reduction ◽  
Acid Pretreatment ◽  
Sludge Management ◽  
Biological Sludge

Abstract Background: Converting wastewater sludge to lipid is considered as one of the best strategies of sludge management. The current problem of lipid production from wastewater sludge is the low yield (0.10-0.16 g lipid/g dry sludge) due to the low availability of easily uptaken materials (such as soluble monosaccharide and oligosaccharide) in sludge to oleaginous microorganism (Rhodotorula glutinis, Trichosporon oleaginosus, Lipomyces starkeyi). Pretreatments are efficient methods to improve sludge bioavailability. This study is aimed to achieve high lipid production from sludge and high sludge reduction. Results: In this study, it was observed that the soluble chemical oxygen demand (SCOD) had significantly increased after different pretreatment. The SCOD in the supernatant was increased from 32.64 to 180.25 mg/L, 924.16 mg/L, 1029.89mg/L and 3708.31 mg/L after acidic (pH 2 for 2 h), alkaline (pH 12 for 2 h), microwave irradiation (15 min with 5 min interval), and ultrasonication (30 min at 450 W and 20 kHz frequency with 5 s on and 2 s off mode) pretreatment, respectively. Pretreatments have also increased the release of total nitrogen (TN) and total phosphorus (TP) from solids. The sludge after different pretreatments were used as medium for lipid production, and the highest lipid content (36.67% g/g) was obtained in the fermentation with ultrasonication pretreatment sludge, and the sludge reduction was 63.10%. For other pretreatments, the lipid content and sludge reduction were 18.42% and 32.63% in acid pretreatment case, 21.08% and 36.44% in alkaline pretreatment case, and 26.31% and 43.03% in microwave pretreatment case, respectively.Conclusion: It was found that ultrasonication pretreatment was the most efficient way to increase the sludge biodegradability (SCOD) and to release TN and TP from solid phase to liquid phase. Pretreated sludge for lipid production achieved significant improvement in lipid yield and sludge reduction. Lipids produced from pretreated sludge were transesterified to biodiesel and the analysis showed that the biodiesel had a similar composition as commercial biodiesel. The study reveals that pretreatment on sludge is a promising method for enhancing biological sludge management efficiency.

scholarly journals Pretreatments for enhancing sewage sludge reduction and reuse in lipid production

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Jiaxin Chen ◽  
Ji Li ◽  
Xiaolei Zhang ◽  
Zhaoyang Wu
Keyword(s):  
Lipid Content ◽  
Solid Phase ◽  
Lipid Production ◽  
Oxygen Demand ◽  
Rhodotorula Glutinis ◽  
Wastewater Sludge ◽  
Sludge Reduction ◽  
Acid Pretreatment ◽  
Sludge Management ◽  
Biological Sludge

Abstract Background Converting wastewater sludge to lipid is considered as one of the best strategies of sludge management. The current problem of lipid production from wastewater sludge is the low yield (0.10–0.16 g lipid/g dry sludge) due to the low availability of easily uptaken materials (such as soluble monosaccharide and oligosaccharide) in sludge to oleaginous microorganism (Rhodotorula glutinis, Trichosporon oleaginosus, Lipomyces starkeyi). Pretreatments are efficient methods to improve sludge bioavailability. This study is aimed to achieve high lipid production from sludge and high sludge reduction. Results In this study, it was observed that the soluble chemical oxygen demand (SCOD) had significantly increased after different pretreatment. The SCOD in the supernatant was increased from 32.64 to 180.25 mg/L, 924.16 mg/L, 1029.89 mg/L and 3708.31 mg/L after acidic (pH 2 for 2 h), alkaline (pH 12 for 2 h), microwave irradiation (15 min with 5 min interval), and ultrasonication (30 min at 450 W and 20 kHz frequency with 5 s on and 2 s off mode) pretreatment, respectively. Pretreatments have also increased the release of total nitrogen (TN) and total phosphorus (TP) from solids. The sludge after different pretreatments were used as a medium for lipid production, and the highest lipid content (36.67% g/g) was obtained in the fermentation with ultrasonication pretreatment sludge, and the sludge reduction was 63.10%. For other pretreatments, the lipid content and sludge reduction were 18.42% and 32.63% in acid pretreatment case, 21.08% and 36.44% in alkaline pretreatment case, and 26.31% and 43.03% in microwave pretreatment case, respectively. Conclusion It was found that ultrasonication pretreatment was the most efficient way to increase the sludge biodegradability (SCOD) and to release TN and TP from solid phase to liquid phase. Pretreated sludge for lipid production achieved significant improvement in lipid yield and sludge reduction. Lipids produced from pretreated sludge were transesterified to biodiesel and the analysis showed that biodiesel had a similar composition as commercial biodiesel. The study reveals that pretreatment on sludge is a promising method for enhancing biological sludge management efficiency.

scholarly journals Pretreatments for enhancing sewage sludge reduction and reuse in lipid production

2020 ◽  
Author(s):  
Jiaxin Chen ◽  
Ji Li ◽  
Xiaolei Zhang ◽  
Zhaoyang Wu
Keyword(s):  
Lipid Content ◽  
Solid Phase ◽  
Lipid Production ◽  
Oxygen Demand ◽  
Wastewater Sludge ◽  
Sludge Reduction ◽  
Acid Pretreatment ◽  
Sludge Management ◽  
Biological Sludge ◽  
High Lipid

Abstract Background: Converting wastewater sludge to lipid is considered as one of the best strategies of sludge management. The current problem of lipid production from wastewater sludge is the low yield (0.10-0.16 g lipid/g dry sludge) due to the low availability of easily uptaken materials (such as soluble monosaccharide and oligosaccharide) in sludge to oleaginous microorganism (Rhodotorula glutini, Trichosporon oleaginosus, Lipomyces starkey). Pretreatments are efficient methods to improve sludge bioavailability. This study is aimed to achieve high lipid production from sludge and high sludge reduction. Results: In this study, it was observed that the soluble chemical oxygen demand (SCOD) had significantly increased after different pretreatment.The SCOD in the supernatant was increased from 32.64 to 180.25 mg/L, 924.16 mg/L, 1029.89mg/L and 3708.31 mg/L after acidic (pH 2 for 2 h), alkaline (pH 12 for 2 h), microwave irradiation (15 min with 5 min interval) and ultrasonication (30 min at 450 W and 20 kHz frequency with 5 s on and 2 s off mode) pretreatment, respectively. Pretreatments have also increased the release in total nitrogen (TN) and total phosphorus (TP) from solids. The sludge after different pretreatments were used as medium for lipid production, and the highest lipid content (36.67% g/g) was obtained in the fermentation with ultrasonication pretreatment sludge, and the sludge reduction was 63.10%. For other pretreatment, the lipid content and sludge reduction were 18.42% and 32.63% in acid pretreatment case, 21.08% and 36.44% in alkaline pretreatment case, and 26.31% and 43.03% in microwave pretreatment case, respectively.Conclusion: It was found that ultrasonication pretreatment was the most efficient way to increase the sludge biodegradability (SCOD) and to release TN and TP from solid phase to liquid phase. Pretreated sludge for lipid production achieved significant improvement in lipid yield and sludge reduction. Lipids produced from pretreated sludge was transesterified to biodiesel and the analysis showed that the biodiesel had similar composition as commercial biodiesel. The study reveals that pretreatment on sludge is a promising method for enhancing biological sludge management efficiency.

scholarly journals Pretreatments for Enhancing Sewage Sludge Reduction and Reuse in Lipid Production

2020 ◽  
Author(s):  
Jiaxin Chen ◽  
Ji Li ◽  
Xiaolei Zhang ◽  
Zhaoyang Wu
Keyword(s):  
Current Problem ◽  
Solid Phase ◽  
Lipid Production ◽  
Oxygen Demand ◽  
Wastewater Sludge ◽  
Sludge Reduction ◽  
Sludge Management ◽  
Lipid Yield ◽  
Management Efficiency ◽  
Biological Sludge

Abstract Background: Converting wastewater sludge for lipid is considered as one of the best strategies of sludge management. The current problem of lipid production from sludge is the low yield due to the low availability of easily uptaken materials in sludge. Pretreatments are efficient methods to improve sludge bioavailability. Results: In this study, it was observed that the soluable chemical oxygen demand (SCOD) had significantly increased after different pretreatment.The SCOD in the supernatant was increased from 32.64±5.19 to 180±13 mg/L, 924±17 mg/L, 1030±6 mg/L and 3708±22 mg/L after acidic, alkaline, microwave irradiation and ultrasonication pretreatment, respectively. Pretreatments have also increased the release in total nitrogen (TN) and total phosphorus (TP) from solids. The sludge after different pretreatments were used as medium for lipid production, thighest lipid content (36.67% g/g) was obtained in the fermentation with ultrasonication pretreatment sludge, and the sludge reduction was 63.10%.Conclusion: It was found that ultrasonication pretreatment was the most efficient way to increase the sludge biodegradability (SCOD), to release TN and TP from solid phase to liquid phase. Pretreated sludge for lipid production achieved significant improvement lipid yield and sludge reduction. Lipids produced from pretreated sludge was transesterified to biodiesel and the analysis showed that the biodiesel had similar composition as commercial biodiesel. The study reveals that pretreatment on sludge is a promising method for enhancing biological sludge management efficiency.

scholarly journals Investigation of the Relationship between Bacteria Growth and Lipid Production Cultivating of Microalgae Chlorella Vulgaris in Seafood Wastewater

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2282 ◽  
Author(s):  
Thi Dong Phuong Nguyen ◽  
Duc Huy Nguyen ◽  
Jun Wei Lim ◽  
Chih-Kai Chang ◽  
Hui Yi Leong ◽  
...  
Keyword(s):  
Chlorella Vulgaris ◽  
Lipid Content ◽  
Lipid Accumulation ◽  
Lipid Production ◽  
Oxygen Demand ◽  
Value Added ◽  
Bacteria Growth ◽  
Microalgae Culture ◽  
The Relationship ◽  
Microalgae Growth

Algae biorefinery is gaining much attention for the sustainable production of value-added products (e.g., biofuels, protein supplements etc.) globally. The current study aimed to investigate the relationship between lipid production and bacteria growth by an initial microalgae Chlorella vulgaris density culture in seafood wastewater effluent (SWE). According to our results, the initial C. vulgaris concentration in SWE influenced lipid accumulation. The concentration ranged from 25–35 mg·L−1 which corresponds to SWE’s chemical oxygen demand concentration of 365.67 ± 3.45 mg·L−1. A higher microalgae growth rate and lipid content of 32.15 ± 1.45% was successfully attained. A higher lipid content, approximately double, was observed when compared to the control (16.8 ± 0.5%). Moreover, this study demonstrates that bacteria inhibited microalgae growth as the initial cell density stepped over 35 mg·L−1, which also affected lipid accumulation. This study shows an optimal lipid accumulation attained at moderate Chlorella vulgaris density culture in SWE. Hence, wastewater treatment incorporating microalgae culture could be greatly developed in the future to achieve a greener environment.

scholarly journals The Start-Up of Continuous Biohydrogen Production from Cheese Whey: Comparison of Inoculum Pretreatment Methods and Reactors with Moving and Fixed Polyurethane Carriers

2021 ◽  
Vol 11 (2) ◽  
pp. 510
Author(s):  
Elza R. Mikheeva ◽  
Inna V. Katraeva ◽  
Andrey A. Kovalev ◽  
Dmitriy A. Kovalev ◽  
Alla N. Nozhevnikova ◽  
...  
Keyword(s):  
Cheese Whey ◽  
Hydraulic Retention Time ◽  
Continuous Production ◽  
Oxygen Demand ◽  
Organic Load ◽  
Anaerobic Sludge ◽  
Acid Pretreatment ◽  
Methanogenic Activity ◽  
Start Up ◽  
Load Rate

This article presents the results of the start-up of continuous production of biohydrogen from cheese whey (CW) in an anaerobic filter (AF) and anaerobic fluidized bed (AFB) with a polyurethane carrier. Heat and acid pretreatments were used for the inactivation of hydrogen-scavengers in the inoculum (mesophilic and thermophilic anaerobic sludge). Acid pretreatment was effective for thermophilic anaerobic sludge to suppress methanogenic activity, and heat treatment was effective for mesophilic anaerobic sludge. Maximum specific yields of hydrogen, namely 178 mL/g chemical oxygen demand (COD) and 149 mL/g COD for AFB and AF, respectively, were obtained at the hydraulic retention time (HRT) of 4.5 days and organic load rate (OLR) of 6.61 kg COD/(m3 day). At the same time, the maximum hydrogen production rates of 1.28 and 1.9 NL/(L day) for AF and AFB, respectively, were obtained at the HRT of 2.02 days and OLR of 14.88 kg COD/(m3 day). At the phylum level, the dominant taxa were Firmicutes (65% in AF and 60% in AFB), and at the genus level, Lactobacillus (40% in AF and 43% in AFB) and Bifidobacterium (24% in AF and 30% in AFB).

Experimental manipulations of the biomass of introduced carp (Cyprinus carpio) in billabongs. II. Impacts on benthic properties and processes1

1997 ◽  
Vol 48 (5) ◽  
pp. 445 ◽  
Author(s):  
A. I. Robertson ◽  
M. R. Healey ◽  
A. J. King
Keyword(s):  
Algal Biomass ◽  
Solid Phase ◽  
Negative Impact ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Sediment Surface ◽  
Nutrient Concentrations ◽  
Nutrient Ratios ◽  
Biofilm Development ◽  
The Impact

Two billabongs on the floodplain of the Murrumbidgee River, Australia, were partitioned in half with impermeable plastic barriers and the biomass of carp was manipulated to establish high- and low-carp biomass treatments in each billabong. Measurements of benthic variables (rates of particle settlement, biofilm development, sediment respiration, macrophyte detritus decomposition, sediment solid-phase nutrient concentrations and benthic algal biomass) were performed over four months from summer to winter 1995. Rates of particle settlement were greater in the high-carp treatment of each billabong throughout the experiment. High carp biomass had a negative impact on the autotrophic component of the biofilm developing on wood blocks placed at different heights above the sediment surface but the mechanism responsible differed between billabongs. Sediment oxygen demand became greater in the presence of a higher biomass of carp during the experiment but time courses differed between billabongs. Manipulations of carp biomass did not influence algal biomass on the sediment surface, the rate of decomposition of macrophyte detritus or sediment solid-phase nutrients or nutrient ratios. The impact of carp on benthic and surficial processes was significant but the mechanisms of change differed between billabongs.

scholarly journals miR-15b negatively correlates with lipid metabolism in mammary epithelial cells

2018 ◽  
Vol 314 (1) ◽  
pp. C43-C52 ◽  
Author(s):  
Meiqiang Chu ◽  
Yong Zhao ◽  
Shuai Yu ◽  
Yanan Hao ◽  
Pengfei Zhang ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Epithelial Cells ◽  
Steroid Hormones ◽  
Lipid Content ◽  
Mammary Epithelial Cells ◽  
Lipid Production ◽  
Fatty Acid Synthetase ◽  
Lipid Synthesis ◽  
Mammary Epithelial ◽  
Lipid Formation

Mammary epithelial cells are regulated by steroid hormones, growth factors, and even microRNAs. miR-15b has been found to regulate lipid metabolism in adipocytes; however, its effects on lipid metabolism in mammary epithelial cells, the cells of lipid synthesis and secretion, are as yet unknown. The main purpose of this investigation was to explore the effect of miR-15b on lipid metabolism in mammary epithelial cells, along with the underlying mechanisms. miR-15b was overexpressed or inhibited by miRNA mimics or inhibitors; subsequently, lipid formation in mammary epithelial cells, and proteins related to lipid metabolism, were investigated. Through overexpression or inhibition of miR-15b expression, the current investigation found that miR-15b downregulates lipid metabolism in mammary epithelial cells and is expressed differentially at various stages of mouse and goat mammary gland development. Inhibition of miR-15b expression increased lipid content in mammary epithelial cells through elevation of the lipid synthesis enzyme fatty acid synthetase (FASN), and overexpression of miR-15b reduced lipid content in mammary epithelial cells with decreasing levels of FASN. Moreover, the steroid hormones estradiol and progesterone decreased miR-15b expression with a subsequent increase in lipid formation in mammary epithelial cells. The expression of miR-15b was lower during lactation and negatively correlated with lipid synthesis proteins, which suggests that it may be involved in lipid synthesis and milk production. miR-15b might be a useful target for altering lipid production and milk yield.

scholarly journals The Use of Urea and Kelp Waste Extract is A Promising Strategy for Maximizing the Biomass Productivity and Lipid Content in Chlorella sorokiniana

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 463 ◽  
Author(s):  
Ali Nawaz Kumbhar ◽  
Meilin He ◽  
Abdul Razzaque Rajper ◽  
Khalil Ahmed Memon ◽  
Muhammad Rizwan ◽  
...  
Keyword(s):  
Lipid Content ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Lipid Production ◽  
Total Lipid Content ◽  
Biomass Productivity ◽  
Chlorella Sorokiniana ◽  
Biofuel Production ◽  
Promising Strategy ◽  
Waste Extract

The decline in fossil fuel reserves has forced researchers to seek out alternatives to fossil fuels. Microalgae are considered to be a promising feedstock for sustainable biofuel production. Previous studies have shown that urea is an important nitrogen source for cell growth and the lipid production of microalgae. The present study investigated the effect of different concentrations of urea combined with kelp waste extract on the biomass and lipid content of Chlorella sorokiniana. The results revealed that the highest cell density, 20.36 × 107 cells−1, and maximal dry biomass, 1.70 g/L, were achieved in the presence of 0.5 g/L of urea combined with 8% kelp waste extract. Similarly, the maximum chlorophyll a, b and beta carotenoid were 10.36 mg/L, 7.05, and 3.01 mg/L, respectively. The highest quantity of carbohydrate content, 290.51 µg/mL, was achieved in the presence of 0.2 g/L of urea and 8% kelp waste extract. The highest fluorescence intensity, 40.05 × 107 cells−1, and maximum total lipid content (30%) were achieved in the presence of 0.1 g/L of urea and 8% kelp waste extract. The current study suggests that the combination of urea and kelp waste extract is the best strategy to enhance the biomass and lipid content in Chlorella sorokiniana.

Sign in / Sign up

Export Citation Format

Share Document