scholarly journals Impact of Starch from Cassava Peel on Biogas Produced through the Anaerobic Digestion Process

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2713 ◽  
Author(s):  
Alla Mohammed Alrefai ◽  
Raid Alrefai ◽  
Khaled Younis Benyounis ◽  
Joseph Stokes
Keyword(s):  
Anaerobic Digestion ◽  
Energy Balance ◽  
Volatile Solid ◽  
Influence Of Temperature ◽  
Digestion Process ◽  
Pre Treatment ◽  
The Impact ◽  
First Time ◽  
Cassava Peel

Cassava is a form of food that is rich in starch abundant in many countries. Several bio-products can be extracted from its starch and used as an alternative for oil-based products. This study primarily aims to investigate the influence of the starch isolated from cassava peel on the quantity and quality of the biogas produced via anaerobic digestion. Beating pre-treatment was applied for the first time to isolate the starch and mechanically pre-treat the substrate. The influence of temperature, volatile solid and sludge quantity investigations were analysed with the aid of Design of Experiments (DOE). An optimisation process was applied in calculating the energy balance at the optimal results and this was needed in evaluating the impact of the starch on the biogas produced. The study revealed that the influence of the starch on the biogas quality is quite low and, as such, negligible. The largest biogas volume as obtained was 3830 cc at 37 °C, 4.2 g-VS and 50% sludge quantity, while at the same time the maximum CH4 g−1-VS was 850 cc g−1-VS at 37 °C, 1.1 g-VS and 50% sludge quantity. The optimal results show the energy gain could be achieved based on the set criteria.

scholarly journals Anaerobic mesophilic digestion of sludge with extra-thermophilic and high ph pre-treatment

2019 ◽  
pp. 451-463 ◽  
Author(s):  
Anne Menert ◽  
Ergo Rikmann ◽  
Merje Michelis ◽  
Tarmo Vaalu ◽  
Viktoria Blonskaja ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Elevated Temperatures ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Cumulative Volume ◽  
Mesophilic Digestion ◽  
Naoh Treatment ◽  
Pre Treatment

In this study different methods of sludge pre-treatment with elevated temperatures andpH have been selected for investigation. Five sets of sludge samples were pretreated asfollows: heating at 70°C for 30 min, at 80°C for 20 min, at 90°C for 10 min, at 100°C forWWTP5 min and NaOH-treatment (pH 12 for 4 hours). For comparison a sample from Tallinn(3:1 mixture of primary (dry solids 5.2%) and activated sludge (dry solids 0.5%))was used. Extra-thermophilic pre-treatment increased the degree of hydrolyses of sludge,enabling the following anaerobic digestion process to proceed faster than that of rawsludge. However, extra-thermophilic pre-treatment was insufficient for removal ofnitrogen and phosphorous. Nitrogen can be easily solubilized during extra-thermophilicpre-treatment but solubilization of phosphorous occurs only through digestion. Theproduction of biogas during anaerobic digestion was also dependant on the quality of theinput of pre-treated sludge. The highest cumulative volume of biogas (124 mUg CODadded) was achieved by pre-treatment at 80°C. The percentage of mineralization of pretreated sludges on mesophilic digestion was the highest with 90°C sample - 65.9%.

scholarly journals Endonasal endoscopic reoperation for residual or recurrent craniopharyngiomas

2017 ◽  
Vol 126 (2) ◽  
pp. 418-430 ◽  
Author(s):  
Sivashanmugam Dhandapani ◽  
Harminder Singh ◽  
Hazem M. Negm ◽  
Salomon Cohen ◽  
Mark M. Souweidane ◽  
...  
Keyword(s):  
Tumor Volume ◽  
Visual Outcome ◽  
Extent Of Resection ◽  
Endocrine Function ◽  
Subtotal Resection ◽  
Total Resection ◽  
Medical College ◽  
The Impact ◽  
First Time

OBJECTIVE Craniopharyngiomas can be difficult to remove completely based on their intimate relationship with surrounding visual and endocrine structures. Reoperations are not uncommon but have been associated with higher rates of complications and lower extents of resection. So radiation is often offered as an alternative to reoperation. The endonasal endoscopic transsphenoidal approach has been used in recent years for craniopharyngiomas previously removed with craniotomy. The impact of this approach on reoperations has not been widely investigated. METHODS The authors reviewed a prospectively acquired database of endonasal endoscopic resections of craniopharyngiomas over 11 years at Weill Cornell Medical College, NewYork-Presbyterian Hospital, performed by the senior authors. Reoperations were separated from first operations. Pre- and postoperative visual and endocrine function, tumor size, body mass index (BMI), quality of life (QOL), extent of resection (EOR), impact of prior radiation, and complications were compared between groups. EOR was divided into gross-total resection (GTR, 100%), near-total resection (NTR, > 95%), and subtotal resection (STR, < 95%). Univariate and multivariate analyses were performed. RESULTS Of the total 57 endonasal surgical procedures, 22 (39%) were reoperations. First-time operations and reoperations did not differ in tumor volume, radiological configuration, or patients' BMI. Hypopituitarism and diabetes insipidus (DI) were more common before reoperations (82% and 55%, respectively) compared with first operations (60% and 8.6%, respectively; p < 0.001). For the 46 patients in whom GTR was intended, rates of GTR and GTR+NTR were not significantly different between first operations (90% and 97%, respectively) and reoperations (80% and 100%, respectively). For reoperations, prior radiation and larger tumor volume had lower rates of GTR. Vision improved equally in first operations (80%) compared with reoperations (73%). New anterior pituitary deficits were more common in first operations compared with reoperations (51% vs 23%, respectively; p = 0.08), while new DI was more common in reoperations compared with first-time operations (80% vs 47%, respectively; p = 0.08). Nonendocrine complications occurred in 2 (3.6%) first-time operations and no reoperations. Tumor regrowth occurred in 6 patients (11%) over a median follow-up of 46 months and was not different between first versus reoperations, but was associated with STR (33%) compared with GTR+NTR (4%; p = 0.02) and with not receiving radiation after STR (67% vs 22%; p = 0.08). The overall BMI increased significantly from 28.7 to 34.8 kg/m2 over 10 years. Six months after surgery, there was a significant improvement in QOL, which was similar between first-time operations and reoperations, and negatively correlated with STR. CONCLUSIONS Endonasal endoscopic transsphenoidal reoperation results in similar EOR, visual outcome, and improvement in QOL as first-time operations, with no significant increase in complications. EOR is more impacted by tumor volume and prior radiation. Reoperations should be offered to patients with recurrent craniopharyngiomas and may be preferable to radiation in patients in whom GTR or NTR can be achieved.

scholarly journals Testing the Impact of Waste from Anaerobic Digestion (Enriched with an Organic Component) on the Quality of Agricultural Land

2017 ◽  
Vol 63 (4) ◽  
pp. 33-38
Author(s):  
Jana Kodymová ◽  
Miroslav Kyncl ◽  
Hana Švehláková ◽  
Magdaléna Bártková
Keyword(s):  
Anaerobic Digestion ◽  
Field Trial ◽  
Laboratory Tests ◽  
Agricultural Land ◽  
Mineral Fertilizer ◽  
Organic Component ◽  
Carbon And Nitrogen ◽  
Macro And Micronutrients ◽  
The Impact

Abstract Waste from anaerobic digestion is considered as a mineral fertilizer and it is usually applied to agricultural land. The aim of our attempt was to enrich this waste from anaerobic digestion (digestate) with an organic component (in our case represented by haylage). For this purpose, we made different mixtures of digestate and haylage in different weight ratios. In the field trial, the effect of these mixtures on the soil, under standard agricultural conditions, was monitored. Selected accessible nutrients (P, K, Mg, Mn, Ca) and the amount of carbon and nitrogen in the soil were monitored. The results of the laboratory tests confirmed that the areas where the sowing and digestate mixtures were applied showed greater amounts of macro- and micronutrients in plant-accessible forms than the surface fertilized only with digestate or areas fertilized only with standard fertilizers.

scholarly journals Ants' Notion of Zero through the Perception of the Absence of an Odor

2019 ◽  
Vol 11 (2) ◽  
pp. 1
Author(s):  
Marie-Claire Cammaerts ◽  
Roger Cammaerts
Keyword(s):  
Operant Conditioning ◽  
Basic Concept ◽  
Olfactory Conditioning ◽  
Pleasant Odor ◽  
Learning Score ◽  
The Impact ◽  
First Time

Workers of the ant Myrmica sabuleti can acquire the notion of &lsquo;nothing&rsquo;, i.e. a basic concept of zero, through olfactory conditioning, the best when the odor is unpleasant (onion odor) and when the response to the absence of the odor is rewarded. With a pleasant odor (lavender, rosemary or vanilla odor), the ants learn best when the response to the odor is rewarded. To our knowledge this is the first time that olfactory operant conditioning is obtained in animals by rewarding their response to &lsquo;nothing&rsquo;. The present work also points out: - the impact of the kind and quality of the cue to be learned on the animals&rsquo; learning score, - the improvement of a given learning over successive similar learning experiments, - the obtaining of a better learning when the reward is associated with the animals&rsquo; preference.

scholarly journals Significance of Pretreatment in Enhancing the Performance of Dry Anaerobic Digestion of Food Waste: An Insight on Full Scale Implementation Strategy with Theoretical Analogy

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1018
Author(s):  
Vijayalakshmi Arelli ◽  
Sudharshan Juntupally ◽  
Sameena Begum ◽  
Gangagni Rao Anupoju
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Scale Up ◽  
Methane Yield ◽  
Net Energy ◽  
Time Duration ◽  
Methane Generation ◽  
Pre Treatment ◽  
The Impact ◽  
Dry Anaerobic Digestion

The aim of this study was to treat food waste containing 25% total solids (TS) through dry anaerobic digestion (dry AD) process at various pressures (0.5 to 2.5 kg/cm2) and different time duration (20 to 100 min) to understand the impact of pretreatment in enhancing the methane generation potential along with insights on scale up. The findings revealed that vs. reduction and methane yield of 60% and 0.25 L CH4/(g VSadded) can be achieved with pretreated food waste at two kilograms per square centimeter, while pretreatment of food waste at 2 kg/cm2 for 100 min enhanced the vs. reduction from 60% to 85% and methane yield from 0.25 to 0.368 L CH4/(g VSadded). However, the net energy indicated that 40 min of pre -treatment at two kilograms per square centimeter can be a suitable option as methane yield and vs. reduction of 0.272 L CH4/(g VSadded) and 70%, respectively was achieved. The vs. reduction and the methane yield of 45% and 0.14 L CH4/(g VSadded), respectively was obtained from untreated food waste which illustrated that pretreatment had significantly impacted on the enhancement of methane generation and organic matter removal which can make the dry AD process more attractive and feasible at commercial scale.

scholarly journals The Impact of the Quality of Tap Water and the Properties of Installation Materials on the Formation of Biofilms

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1903 ◽  
Author(s):  
Dorota Papciak ◽  
Barbara Tchórzewska-Cieślak ◽  
Andżelika Domoń ◽  
Anna Wojtuś ◽  
Jakub Żywiec ◽  
...  
Keyword(s):  
Tap Water ◽  
Galvanized Steel ◽  
Phosphorus Compounds ◽  
Plate Count ◽  
Nickel Steel ◽  
Quantitative Analyses ◽  
The Impact ◽  
First Time

The article presents changes in the quality of tap water depending on time spent in installation and its impact on the creation of biofilms on various materials (polyethylene (PE), polyvinyl chloride (PVC), chrome-nickel steel and galvanized steel). For the first time, quantitative analyses of biofilm were performed using methods such as: Adenosine 5’-triphosphate (ATP) measurement, flow cytometry, heterotrophic plate count and using fractographical parameters. In the water, after leaving the experimental installation, the increase of turbidity, content of organic compounds, nitrites and nitrates was found, as well as the decrease in the content of chlorine compounds, dissolved oxygen and phosphorus compounds. There was an increase in the number of mesophilic and psychrophilic bacteria. In addition, the presence of Escherichia coli was also found. The analysis of the quantitative determination of microorganisms in a biofilm indicates that galvanized steel is the most susceptible material for the adhesion of microorganisms. These results were also confirmed by the analysis of the biofilm morphology. The roughness profile, the thickness of the biofilm layer can be estimated at about 300 μm on galvanized steel.

Study of Anaerobic Digestion of Model Kitchen Waste

2014 ◽  
Vol 955-959 ◽  
pp. 2692-2696 ◽  
Author(s):  
Li Fan Liu ◽  
Yong Wei Liao ◽  
Jie Liang ◽  
Shu Ting Lai
Keyword(s):  
Anaerobic Digestion ◽  
Carbon Concentration ◽  
Dry Matter ◽  
Biogas Production ◽  
Total Solid ◽  
Volatile Solid ◽  
Kitchen Waste ◽  
Operational Conditions ◽  
Digestion Process ◽  
Seed Sludge

The characteristics such as pH, dry matter, carbon concentration, the total solid and volatile solid of kitchen wastes produced by a canteen in Guangzhou were measured. The anaerobic digestion process performances were evaluated through the examination of operational conditions like activated sludge inoculation, temperature on SS, biogas production, COD concentration and pH in the reactor. When the proportion between kitchen wastes to seed sludge inoculation was 1:1, the biogas production reached the peak at 45 °C. The kitchen waste pH decreased at the first four days then increased adversely after 4 days digestion, but COD concentration showed the opposite variation.

scholarly journals Impact of pre-treatment technologies on soil aquifer treatment

2016 ◽  
Vol 7 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A. Besançon ◽  
M. Pidou ◽  
P. Jeffrey ◽  
B. Jefferson ◽  
K. S. Le Corre
Keyword(s):  
Treatment Options ◽  
Infiltration Rate ◽  
Soil Aquifer Treatment ◽  
Operational Conditions ◽  
Conventional Activated Sludge ◽  
Treatment Train ◽  
Pre Treatment ◽  
The One ◽  
The Impact

This study investigates the impact of pre-treatment options on the performances of soil columns simulating soil aquifer treatment (SAT). For this purpose a conventional activated sludge (CAS) process, a membrane bioreactor (MBR) and vertical flow reed beds were used as single units or in combination before SAT. The influent and effluent from each treatment train were monitored over three successive 6-month periods, corresponding to changes in the operational conditions of the MBR and CAS units from 6 days' sludge retention time (SRT) to 12 and 20 days. All the columns acted as efficient polishing steps for solids and bacteria. The column receiving effluent from the CAS system running at 6 days' SRT also presented high total nitrogen and total phosphorus removals, but this column was also associated with the lowest infiltration rates over that period. While the quality of the effluent from the column following the CAS process increased over 18 months of operation, the effluent quality of the columns receiving MBR effluent degraded. No correlations were found between variations in SRT of the MBR and CAS processes and the columns' performances. Overall, all columns, except the one receiving CAS effluent, underwent a reduction in infiltration rate over 18 months.

Ultrasound pre-treatment for anaerobic digestion improvement

2009 ◽  
Vol 60 (6) ◽  
pp. 1525-1532 ◽  
Author(s):  
S. Pérez-Elvira ◽  
M. Fdz-Polanco ◽  
F. I. Plaza ◽  
G. Garralón ◽  
F. Fdz-Polanco
Keyword(s):  
Anaerobic Digestion ◽  
Energy Balance ◽  
Specific Energy ◽  
Biogas Production ◽  
Pilot Scale ◽  
Laboratory Scale ◽  
Net Generation ◽  
Batch Reactors ◽  
Anaerobic Reactors ◽  
Pre Treatment

Prior research indicates that ultrasounds can be used in batch reactors as pre-treatment before anaerobic digestion, but the specific energy required at laboratory-scale is too high. This work evaluates both the continuous ultrasound device performance (efficiency and solubilisation) and the operation of anaerobic digesters continuously fed with sonicated sludge, and presents energy balance considerations. The results of sludge solubilisation after the sonication treatment indicate that, applying identical specific energy, it is better to increase the power than the residence time. Working with secondary sludge, batch biodegradability tests show that by applying 30 kWh/m3 of sludge, it is possible to increase biogas production by 42%. Data from continuous pilot-scale anaerobic reactors (V=100 L) indicate that operating with a conventional HRT = 20 d, a reactor fed with pre-treated sludge increases the volatile solids removal and the biogas production by 25 and 37% respectively. Operating with HRT = 15 d, the removal efficiency is similar to the obtained with a reactor fed with non-hydrolysed sludge at HTR = 20 d, although the specific biogas productivity per volume of reactor is higher for the pretreated sludge. Regarding the energy balance, although for laboratory-scale devices it is negative, full-scale suppliers state a net generation of 3–10 kW per kW of energy used.

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