Technical feasibility and cost effectiveness of the co-disposal of spent organic solvents and municipal sludges using anaerobic digestion

Industrial water usage results in large volumes of liquid wastes rich in organic pollutants. Waste waters from certain industrial chemical operations (e.g. organic synthesis, perfume industry) will sometimes contain organic solvents at relatively high concentrations. The presence of organic solvents is undesirable in the sewerage system and so must be removed from the industrial effluent. Anaerobic treatment of many of these organic solvents is possible, in which the organic material is converted ~90% to volatile substances -carbon dioxide and methane gas- and ~10% to new bacterial cells (solids). Industry will be using less water in the future. Increased water charges will lead to more precise control and integrated processes will reduce wastage. The smaller volumes of more concentrated waste will be ideal for anaerobic digestion. In order to evaluate the optimum conditions for the anaerobic digestion of propan-2-ol (iso-propanol) the kinetic parameters of the Monod rate model, namely, maximum growth rate (µm), yield (Y), half velocity constant (Ks) and endogenous decay coefficient (Kd), were determined at the temperature range 25°-40°C, inclusively. The regulatory role of molecular hydrogen was investigated and discussed, and also its possible use as a monitor feature in the anaerobic digestion.

Download Full-text

Technical feasibility of reforming anaerobic digestion and landfill biogas streams into bio-hydrogen

Biomass Conversion and Biorefinery ◽

10.1007/s13399-020-00911-x ◽

2020 ◽

Author(s):

Isam Janajreh ◽

Idowu Adeyemi ◽

Sherien Elagroudy

Keyword(s):

Anaerobic Digestion ◽

Technical Feasibility ◽

Landfill Biogas

Download Full-text

Energy Efficiency of Comminution and Extrusion of Maize Substrates Subjected to Methane Fermentation

Energies ◽

10.3390/en13081887 ◽

2020 ◽

Vol 13 (8) ◽

pp. 1887

Author(s):

Kamil Witaszek ◽

Krzysztof Pilarski ◽

Gniewko Niedbała ◽

Agnieszka Anna Pilarska ◽

Marcin Herkowiak

Keyword(s):

Cost Effectiveness ◽

Anaerobic Digestion ◽

Dry Matter ◽

Low Cost ◽

Methane Yield ◽

Maize Silage ◽

Methane Fermentation ◽

Digestion Process ◽

Maize Straw ◽

The Cost

The production of methane in the anaerobic digestion process is a proven technology, but it is characterized by low cost-effectiveness. The pretreatment of substrates seems to be a promising technology, which may increase the cost-effectiveness of biogas installations. The aim of the study was to investigate the influence of the comminution and extrusion of maize silage and maize straw silage on the course and yield of anaerobic digestion. The use of a pretreatment (comminution, extrusion) is justified when its energy balance is positive. The greatest increase in the methane yield per dry matter (12.4%) was observed after the extrusion of maize straw silage at 175 °C. The change in the methane yield resulting from the extrusion of maize silage and maize straw silage at 150 °C was small and amounted to 6.4% and 9%, respectively. The comminution caused an increase in the methane yield and accelerated the fermentation of substrates. The methane yield from maize silage was 38.4%, whereas the yield from maize straw silage was only 8.3%.

Download Full-text

Mathematical model for evaluation of cost-effectiveness of waste treatment technique with energy recovery

Thermal Science ◽

10.2298/tsci16s5573m ◽

2016 ◽

Vol 20 (suppl. 5) ◽

pp. 1573-1584

Author(s):

Biljana Milutinovic ◽

Gordana Stefanovic ◽

Ksenija Dencic-Mihajlov ◽

Petar Djekic ◽

Aleksandra Boricic

Keyword(s):

Mathematical Model ◽

Cost Effectiveness ◽

Anaerobic Digestion ◽

Energy Recovery ◽

Waste Treatment ◽

Cost Effective ◽

Operating Costs ◽

Treatment Technique ◽

Treatment Facility ◽

The City

A cost-effectiveness of a specific waste treatment technique is very important factor when making the decision to invest in a waste treatment facility. Waste treatment can bring economic benefit through the value of product: recycled materials, the compost, the generated electricity, or heat. However, the expected economic benefits depend on many factors: the investment costs and operating costs of the waste treatment facility, revenues, the market price of the product obtained by waste treatment etc. The investment and operating costs and the revenue also depend on the amount of treated waste. This paper presents a mathematical model for evaluation of cost-effectiveness in the waste treatment technique with energy recovery depending on the amount of waste, i. e. evaluation the minimum amount of waste to be treated for a cost-effective waste treatment technique with energy recovery. To develop the mathematical model, a socio-economic analysis was used. The model is applied to calculate the lower limit of cost-effectiveness in the waste treatment techniques with energy recovery: incineration and anaerobic digestion, in the city of Nis, Serbia, as a case study. The obtained results show that the amount of waste currently generated in the city of Nis is not sufficient for the cost-effective incineration treatment, but with the currently available amount of waste, anaerobic digestion is the waste treatment that can be operated without losses in the city of Nis.

Download Full-text

Modified three port laparoscopic cholecystectomy versus conventional four port technique

International Journal of Research in Medical Sciences ◽

10.18203/2320-6012.ijrms20202276 ◽

2020 ◽

Vol 8 (6) ◽

pp. 2248

Author(s):

Ritvik Resutra ◽

Rajive Gupta ◽

Madhu Gupta

Keyword(s):

Laparoscopic Cholecystectomy ◽

Cost Effectiveness ◽

Postoperative Pain ◽

Postoperative Analgesia ◽

Postoperative Period ◽

Viable Alternative ◽

Alternative Procedure ◽

Technical Feasibility ◽

Cosmetic Appearance

Background: The current study was undertaken to compare the results of modified three-port laparoscopic cholecystectomy and conventional three or four-port surgery in terms of technical feasibility, safety of the technique, postoperative pain and need of post-operative analgesia, cosmetic satisfaction of the patient and cost effectiveness and were found to be better with the modified technique.Methods: In modified three port laparoscopic cholecystectomy technique, first 10 mm umbilical, second 5 mm epigastric and third 5 mm subcostal ports are made, i.e., "10-5-5" instead of "10-10-5" or "10-10-5-5" of conventional three or four port techniques and finally, gallbladder is extracted through the umbilical port.Results: The pain in the postoperative period and the requirement of postoperative analgesia were significantly less and there was better cosmetic satisfaction of the patients operated by the modified three port laparoscopic cholecystectomy technique as compared to conventional three or four port surgery.Conclusions: The modified three-port laparoscopic cholecystectomy technique is safe and has the same comfort and feasibility to the surgeon along with added advantage of less pain and better cosmetic appearance to the patient in comparison to the conventional three or four-port surgery, with no obvious increase in complications and is definitely a viable alternative procedure for the management of cholelithiasis.

Download Full-text