Preliminary study of rambutan (Nephelium lappaceum) seed as potential biocoagulant for turbidity removal

This experiment was performed to determine the ability of the coagulation performance of rambutan seed in comparison to alum for potential use in turbidity removal in water and wastewater treatment industry. Experiments were conducted to find the optimum operating conditions for coagulation process such as coagulant dosage and pH and also suitable extracting solvent for the active agent (distilled water, NaCl and NaOH). 1 M NaCl was found to be an effective solvent for extracting the active coagulant agent in rambutan seed and gave about 99 % turbidity removal. The optimum rambutan seed dosages and pH was 100 mg/l and pH 3, resulting in > 90% turbidity removal. In order to reduce dependency on alum, 50% alum and 50% rambutan seed as coagulant combination was used in the order of alum first followed by rambutan seed. The highest turbidity removal of 99% was achieved compared to when using alum (91%) and seed (88%) alone. Rambutan seed coagulant exhibited faster sedimentation time due to bigger flocs formation and also smaller sludge volume than alum. The results suggest potential of using rambutan biomass as biocoagulant

Detoxification of sago trunk hydrolysate using activated charcoal for xylitol production.

Xylitol is one of the alternative natural sweeteners; belong to a group of sugar alcohol. It can be derived from D- xylose which mainly contains in lignocellulose materials. In this study sago trunk cortex was chosen as lignocellulose source due to its availability and abundant in the sago starch processing industry. The production of xylitol includes hydrolysis which breaks the cellulose and hemicellulose polymers to fermentable sugar, mainly xylose, followed by fermentation process which converts the sugars to xylitol. However, some by-products such as furfural and phenolic are released during chemical hydrolysis and inhibit fermentation process. Detoxification procedures were carried out over sago trunk hydrolysates. Powdered activated charcoal was mixed with the hydrolysate at 1% and 2.5% (w/v) and stirred for 30 and 60 minutes at room temperature. The recovery of xylitol was performed using yeast Candida tropicalis in sago trunk cortex hydrolysate. This study describes detoxification methods of sago trunk cortex hydrolysates to improved xylitol production by Candida tropicalis. The effects of 1% and 2.5% (w/v) activated charcoal were identified to the growth and xylitol concentration. This study found that with the application of activated charcoal method, it enabled a reduction of furfural (58%) and total phenolics (78%) compounds. The best conditions was achieved with 2.5% activated charcoal at adsorption time of 60 minutes and the maximum xylitol concentration, xylitol yield and volumetric productivity obtained were 19.53 g l-1, 0.78 g g-1 and 0.37 g l-1 h-1. The value of xylitol yield using the detoxification hydrolysate medium was higher when compared to non-treated medium (0.307 g g-1). This strongly suggests that detoxification method using activated charcoal has a significant impact in xylitol production

Overliming effects on xylitol production from sago trunk hydrolysate

Xylitol can be obtained from lignocellulosic materials containing xylose. However, the fraction of lignocellulose converted through dilute acid hydrolysis contains compounds that inhibit the fermenting micro-organisms. These inhibitors can be removed from the hydrolysate by detoxification method, prior to fermentation. This study describes effectiveness of overliming process to reduce the toxicity of hydrolysates generated from pre-treatment of sago trunk for xylitol production. The overliming pH 9 and 10 was studied and the results showed that pH 9 was showed 20% of sugar loss, which is low compared to pH 10. Candida tropicalis strain was used to evaluate the fermentability of overlimed sago trunk hydrolysate at pH 9 and non-overlimed hydrolysate medium. Meanwhile, Xylitol accumulation and productivity in the overlimed medium was found to be higher than the non-treated medium. The maximum production of xylitol was increased up to 74% and converted within 76 h. The results obtained improved the fermentation process when compared with the non-treated medium

Optimization of xylose production from sago trunk cortex by acid hydrolysis

Sago trunk cortex is a renewable source for the production of many useful products, such as xylose and xylitol. The potential of bioconversion xylose to xylitol from sago trunk cortex is justifiable as these materials are cheap and widespread sugar sources. Lignocellulose type of residue such as sago trunk cortex structure can break to their monomeric sugars with hydrolysis process. Various hydrolysis temperature and acid concentration at constant temperature were investigated to evaluate the potential maximum xylose concentration in the sago trunk hydrolysate. The objectives of this study were to determine the composition of sago trunk cortex and the effects of sulphuric acid (H2SO4) concentration and hydrolysis time on the production of xylose from sago cortex waste. Response surface methodology (RSM) based on central composite design (CCD) was used to optimize the hydrolysis conditions in maximizing the xylose concentration. The optimum hydrolysis time and acid concentration found were 60 min and 8%, respectively. Under these conditions, the xylose concentration achieve was 22.78 g/l. The study provides efficient analysis on optimizing xylose concentration, in order to obtain higher productivity and yield of xylitol

Preliminary evaluation of a hydrophilic microfiltration membrane in treating high strength wastewater

In this study, two types of flat sheet membranes were produced and tested in the laboratory. These types of membranes are hydrophilic and hydrophobic flat sheet membranes. The membranes were prepared using a phase-inversion technique. Three synthetic based polymers were used to produce the membrane. These polymers are polysulfone (PSF), polyethylene glycol (PEG), and N-methyl- 2-pyrrolidone (NMP). Fourteen polymer solutions were formulated by Response Surface Method and the polymers concentrations used were 15 wt % for PSF, 30–40 wt % for PEG and 45–55 wt % for NMP. The produced membranes were physically characterized by scanning electron microscope (SEM) measurements of their top surface and cross-section images. The produced membranes are used to test the flux value for pure water, synthetic wastewater and raw wastewater using a bench scale unit. Meanwhile, the rejection performance is evaluated using synthetic wastewater and raw wastewater. The pure water flux for the hydrophobic membrane ranges from 78.45 L/m2h to 88.05 L/m2h, while pure water flux for the hydrophilic membrane ranges from 41.92 L/m2h to 52.25 L/m2h. Meanwhile, the COD rejection rate from raw wastewater was greater for the hydrophilic membrane (58%) compared to the hydrophobic membrane (42%). Results obtained from the bench scale unit show a gradual increase in the percentage removal of COD, BOB and TOC with time and it increased from 0 to 75% from the 1st day to the 8th day while only a 20% increment was observed from the 8th day up to the end of the test. But, the percentage removal obtained form hydrophilic membrane is slightly higher than the percentage removal of the hydrophobic membrane

Effects of temperature and pH on xylitol recovery from oil palm empty fruit bunch hydrolysate by Candida tropicalis

Oil Palm Empty Fruit Bunch (OPEFB) is composed of pentose that can be used as a raw material for the production of xylitol, a potential application in the food and medical areas. The effects of temperature and pH on xylitol bioconversion by yeast sp. Candida tropicalis were investigated. The optimum pH resulted to be in the range of 2-4. The percentage of xylose consumed for xylitol production progressively increased with pH, whereas those associated to both biomass growth and catabolic reaction through the TCA cycle decreased, reaching nearly constant values at pH 4. The optimum temperature range for xylitol production was 30-35°C. Xylitol formation became the most significant activity at 20°C, further increased up to 30-35°C and then decreased over 40°C. The results collected at variable temperature were finally used for estimation of the parameters of the fermentation system

Response surface optimization of conditions for clarification of carambola fruit juice using a commercial enzyme.

Response surface methodology (RSM) was employed for simultaneous analysis of the effects of enzymatic treatment conditions of incubation time, incubation temperature and enzyme concentration on physical characteristics such as turbidity, clarity, viscosity, and color. In this study, a two-factor central composite design was used to establish the optimum conditions for the enzymatic treatment for clarification of carambola fruit juice. Carambola fruit juice was treated with pectinase enzyme at different incubation time (20–100 min), incubation temperature (30–50 °C) and enzyme concentration (0.01–0.10 v/v%). These three variables were used as independent variables, whose effects on turbidity, clarity, viscosity and color were evaluated. Significant regression models describing the changes on turbidity, clarity, viscosity and color with respect to the independent variables were established with coefficient of determination, R2, greater than 0.70. The results indicated that the enzyme concentration was the most important factor affecting the characteristics of the carambola fruit juice as it exerted a significant influence on most of the dependent variables. The recommended enzymatic treatment condition from the study was at 0.10% enzyme concentration at 30 °C for 20 min

Comparison on optimization of star fruit juice using RSM between two Malaysian star fruit varieties (B11 and B10)

In Malaysia, two star fruit varieties, B11 and B10, are planted for commercial purposes. These types of star fruits are suitable for making juices. However, the fresh star fruit juice is cloudy, viscous and green in colour, necessitating the use of enzymes to clarify the juice. Thus, the aim of this study was to establish the optimum conditions for enzymatic treatment of star fruit (B11) juice using response surface methodology (RSM) and to compare the optimum conditions of this variety (B11) with the B10. Star fruit juice (B11) was treated with pectinase enzyme at different enzyme concentrations, incubation times, and temperatures. The effect of this enzymatic treatment was analyzed based on turbidity, clarity, and viscosity. The regression models describing the changes of turbidity, clarity and viscosity were established with the coefficient of determination, R2, which were greater than O.S. The optimum operating conditions for clarifying star fruit juice (B11) was found to be at 0.01 % enzyme concentration at 30 min of incubation time and 30°C of temperature using response surface methodology. The method of treatments for B10 was similar to that of B11. The two varieties of star fruit (B11 and B10) showed different optimum conditions on enzyme concentration and incubation time; however there was no difference in terms of incubation temperature at optimum conditions

Influence of cationic polyelectrolyte coagulant on microfiltration performance for treatment of oxidation pond effluent

A laboratory scale microfiltration membrane unit was set up to assess the effectiveness of the microfiltration in polishing oxidation pond effluent. In addition, batch pretreatment with polyelectrolyte coagulant was conducted to assess the improvement in flux and filtrate production during coagulation-microfiltration. Results revealed about 500% increase in steady state flux during coagulation-microfiltration process. Moreover, integration of microfiltration with coagulation also improved the quality of effluent, in terms of turbidity and COD removals. About 50–60% and 75% removals were recorded for COD and turbidity, respectively during coagulation-microfiltration which was greater than those obtained during microfiltration alone

Reusability of sewage sludge in clay bricks

Bricks produced from sewage sludge in different compositions were investigated. Results of the tests indicated that the sludge proportion is a key factor in determining the brick quality. Increasing the sludge content results in a decrease in brick shrinkage, bulk density, and compressive strength. Brick weight loss on ignition was mainly due to the contribution of the contained organic matter from the sludge being burnt off during the firing process, as well as inorganic substances found in both clay and sludge. The physical, mechanical, and chemical properties of the bricks that were supplemented with various proportions of dried sludge from 10 to 40thinspwt% and generally complied with the General Specification for Brick as per the Malaysian Standard MS 7.6:1972, which dictates the requirements for clay bricks used in walling in general. A standard leaching test method also showed that the leaching of metals from the bricks is very low