Membrane Anaerobic System (MAS) for Palm Oil Mill Effluent (POME) Treatment

The direct discharge of palm oil mill effluent (POME) wastewater causes serious environmental pollution due to its high chemical oxygen demand (COD) and biochemical oxygen demand (BOD). Traditional ways for POME treatment have both economic and environmental disadvantages. In this study, membrane anaerobic system (MAS) was used as an alternative, cost effective method for treating POME. Six steady states were attained as a part of a kinetic study that considered concentration ranges of 8,220 to 15,400 mg/l for mixed liquor suspended solids (MLSS) and 6, 329 to 13,244 mg/l for mixed liquor volatile suspended solids (MLVSS). Kinetic equations from Monod, Contois and Chen & Hashimoto were employed to describe the kinetics of POME treatment at organic loading rates ranging from 2 to 13 kg COD/m3/d. throughout the experiment, the removal efficiency of COD was from 94.8 to 96.5% with hydraulic retention time, HRT from 400.6 to 5.7 days. The growth yield coefficient, Y was found to be 0.62gVSS/g COD the specific microorganism decay rate was 0.21 d-1 and the methane gas yield production rate was between 0.25 l/g COD/d and 0.58 l/g COD/d. Steady state influent COD concentrations increased from 18,302 mg/l in the first steady state to 43,500 mg/l in the sixth steady state. The minimum solids retention time, which was obtained from the three kinetic models ranged from 5 to 12.3 days. The k values were in the range of and values were between 0.26 and 0.379 d-1. The solids retention time (SRT) decreased from 800 days to 11.6 days. The complete treatment reduced the COD content to 2279 mg/l equivalent to a reduction of 94.8% reduction from the original

Comparison of Essential Oil of Lemongrass (Cymbopogon Citratus) Extracted with Microwave-Assisted Hydrodistillation (MAHD) and Conventional Hydrodistillation (HD) Method

The increasing demand of essential oil has opened up wide opportunities for global marketing which leads to the requirement of its competitive product in market that comes with all the advantages in term of cost, quality and its production time. Microwave-assisted hydrodistillation (MAHD) method is an advance extraction technique that takes advantage of microwave heating with the conventional hydrodistillation (HD). This research was carried out to study the effect of different MAHD parameters which were water to plant material ratio (6:1, 8:1,10:1), microwave power (200 W,250W) and extraction time (30min,60min, 90min,120min) in extraction of essential oil from Lemongrass (Cymbopogon Citratus). Its extraction yield and major constituents were analyzed and the results were compared with those of conventional HD. The optimum parameters were found at water to plant material ratio of 8:1, microwave power of 250W and 90 minutes of extraction and the yield obtained under this condition was 1.46%. The gas chromatography/mass spectrometric (GC-MS) analysis showed that the content of main constituents which were neral, geranial and myrcene were almost similar in the essential oil extracted using MAHD and conventional HD. This has proved that the use of microwave irradiation did not adversely influence the composition of essential oils. Overall, the results obtained indicate that MAHD method provided a good alternative for the extraction of essential oil from Lemongrass (Cymbopogon Citratus)

Demulsification of petroleum emulsions using microwave separation method

The formation of emulsions during oil production and processing is a costly problem, both in terms of chemicals used and production losses. For economic and operational reasons, it is necessary to separate the water completely from crude oils before transporting or refining them. Experimental data are presented to show the influences of Triton X-100, low-sulfur wax residue (LSWR), sorbitan monooleate (Span 83) and sodium dodecyl sulfate (SDS) on the stability and microwave demulsification of petroleum emulsions. It was found that emulsion stability was related to several parameters including the surfactant concentration, water-to-oil phase ratio (10 to 90%), temperature and agitation speed. Based on this study, a possible emulsion-minimization approach utilizing microwave irradiation is suggested, which could be implemented in refineries. Compared with conventional heating, the use of microwave heating can significantly enhance the demulsification rate, reaching over 90 v/v% for the emulsions studied in this work

Three years clinical experience with intestinal transplantation

BACKGROUND: After the successful evolution of hepatic transplantation during the last decade, small bowel and multivisceral transplantation remains the sole elusive achievement for the next era of transplant surgeons. Until recently, and for the last thirty years, the results of the sporadic attempts of intestinal transplantation worldwide were discouraging because of unsatisfactory graft and patient survival. The experimental and clinical demonstration of the superior therapeutic efficacy of FK 506, a new immunosuppressive drug, ushered in the current era of small bowel and multivisceral transplantation with initial promising results. STUDY DESIGN: Forty-three consecutive patients with short bowel syndrome, intestinal insufficiency, or malignant tumors with or without associated liver disease, were given intestinal (n=15), hepatic and intestinal (n=21), or multivisceral allografts that contained four or more organs (n=7). Treatment was with FK 506 based immunosuppression. The ascending and right transverse colon were included with the small intestine in 13 of the 43 grafts, almost evenly distributed between the three groups. RESULTS: After six to 39 months, 30 of the 43 patients are alive, 29 bearing grafts. The most rapid convalescence and resumption of diet, as well as the highest three month patient survival (100 percent) and graft survival (88 percent) were with the isolated intestinal procedure. However, this advantage was slowly eroded during the first two postoperative years, in part because the isolated intestine was more prone to rejection. By the end of this time, the best survival rate (86 percent) was with the multivisceral procedure. With all three operations, most of the patients were able to resume diet and discontinue parenteral alimentation, and in the best instances, the quality of life approached normal. However, the surveillance and intensity of care required for these patients for the first year, and in most instances thereafter, was very high, being far more than required for patients having transplants of the liver, kidney or heart. CONCLUSIONS: Although intestinal transplantation has gone through the feasibility phase, strategies will be required to increase its practicality. One possibility is to combine intestinal transplantation with contemporaneous autologous bone marrow transplantation

A Comparative Investigation on Petroleum Demulsification Techniques (Centrifuge and Green Chemicals Versus Conventional Chemicals)

The breaking (demulsification) of 50-50% w/o petroleum emulsions of two oils (A and B) by Green (chemical and centrifuge) methods were studied in comparison to conventional (chemical) method. The green methods consisted of silicon based chemical demulsifiers and high-speed centrifuge operated at 12,000 RPM, while the conventional method consisted of Amine group based demulsifiers. In chemical method, the concentrations were varied (0.5%, 1.5% and 3%), while in centrifuge method, the processing time was varied (10 and 30 minutes). The efficiency of these methods was determined by measuring the amount of water separated from the emulsion after being treated. The maximum separation efficiencies for Silicon demulsifiers were 93 and 88% for oils A and B respectively, and that of Amine group demulsifiers were 72 and 86% for oils A and B respectively, While centrifuge demulsification gave maximum separations of 39 and 24% for oils A and B respectively. Based on these results, Silicon based demulsifiers are very effective and reliable method to treat emulsions for different types of oils with different composition, and have the potential to be used as an alternative method in the demulsification or breaking of water-in-crude oil emulsions

Abdominal multivisceral transplantation

Under FK506-based immunosuppression, 13 abdominal multivisceral transplantations were performed in 6 children and 7 adults. Of the 13 recipients, 7 (53.8%) are alive and well with functioning grafts after 9 to 31 months. Six recipients died: Three from PTLD, one from rejection, one from sepsis, and one from respiratory failure. In addition to rejection, postoperative complications occurring in more than isolated cases included PTLD (n=6), abdominal abscess formation (n=5), pancreatitis (n=3), and ampullary dysfunction (n=2). In addition, infection by enteric microorganisms was common during the early postoperative period. Currently, all 7 survivors are on an oral diet and have normal liver function. Two recipients (one insulin-dependent) require antidiabetes treatment, in one case following distal pancreatectomy and in the other after two episodes of pancreatic rejection. Thus, abdominal multivisceral transplantation is a difficult but feasible operation that demands complex and prolonged posttransplantation management. It is not yet ready for application and awaits a better strategy of immune modulation. © 1995 by Williams & Wilkins

Exact implicit Solution of Nonlinear Heat Transfer in Rectangular Straight Fin Using Symmetry Reduction Methods

In this paper, the exact implicit solution of the second order nonlinear ordinary differential equation which governing heat transfer in rectangular fin is obtained using symmetry reduction methods. General relationship among the temperature at the fin tip, the temperature gradient at the fin base, the mode of heat transfer, and the fin parameters and ℰ is obtained. Some numerical examples are discussed and it is shown that the temperature of fin increases when approaching from the heat source. The relationship between the fin efficiency and the temperature of fin tip is obtained for any value of the mode of heat transfer . The relationship between the fin efficiency and both the parameter and ε the temperature gradient at the fin base is obtained. To our best knowledge, solutions obtained in this paper are new

The Potential of Ultrasonic Membrane Anaerobic Systems in Treating Slaughterhouse Wastewater

Direct discharge of slaughterhouse wastewater causes serious environmental pollution due to its high chemical oxygen demand (COD), total suspended solids and biochemical oxygen demand. In this study, an ultrasonic-assisted membrane anaerobic system was used as a novel method for treating slaughterhouse wastewater. Six steady states were achieved, using concentrations of 7,800–13,620 mg/l for mixed liquor suspended solids and 5,359–11,424 mg/l for mixed liquor volatile suspended solids. Kinetic equations were used to describe the kinetics of treatment at organic loading rates of 3–11 kg COD/m3/d. The removal efficiency of COD was 94.8–96.5% with hydraulic retention times of 308.6–8.7 days. The growth yield coefficient was found to be 0.52 g VSS/g. COD was 0.21 d−1 and methane gas production rate was 0.24–0.56 l/g COD/d. Steady-state influent COD concentrations increased from 8,000 mg/l in the first steady state to 25,400 mg/l in the sixth steady state. The minimum solids retention time, θcmin obtained from the three kinetic models was 6–14.4 days. The k values were 0.35–0.519 g COD/g VSS.d and μmax values were between 0.26 and 0.379 d−1. The solids retention time decreased from 600 to 14.3 days. The complete treatment reduced the COD content and its removal efficiency reached to 94.8%

Mechanism of Microwave Assisted Hydrodistillation Studied Through Heat Analysis

In this study, the efficiency of heating mechanism of microwave assisted hydrodistillation (MAHD) in the extraction of cinnamon bark oil was investigated. The optimum conditions used to analyse the heating performance were 8:1 ratio of water to cinnamon bark powder and fixed 250 W of irradiation power. The increasing temperature in the cinnamon bark matrix was dependent on the solvent, physical, dielectric and heating properties of the cinnamon matrix. Due to the high dielectric properties of water it accelerated the process of extraction. However, after the cinnamon matrix reached the boiling point, the density of solvent decreased which led to decrease in the dielectric properties. Volume rate of heat generation and penetration depth of microwave was also evaluated. The rate of volume heat generation reduced when the exposure time increase which is related to the reducing dielectric properties of cinnamon matrix. The penetration depth was calculated to support the data of dielectric properties. This study therefore produced an in depth justification necessary to understand the heating mechanism of MAHD in extraction of cinnamon bark essential oil