Characteristics of decomposed waste in landfill

A thorough laboratory investigation is carried out to determine the characteristics of decomposed waste of municipal solid waste dumping site of Rajshahi City Corporation. Samples are collected from various depths by driving PVC pipe in different locations of the dumping site. A rigorous laboratory analysis on collected samples reveals that the concentrations of most of the constituents are higher in all depths compared to Bangladesh Environmental Quality Standard. In the case of heavy metal like Lead and Cadmium, the concentration upto 4.5 ft depth goes beyond the toxic limit. The concentrations of all constituents are decreasing trend in higher depths of fill. The constituents of the higher depths are percolated more through the unlined bottom of this crude dumping site. The decomposed waste at the crude dumping site and also other places after replacing has a potential threat of groundwater and surface water pollution

Solid waste recycling scenario of Rajshahi City, Bangladesh

Rajshahi city, the divisional headquarters of Bangladesh, generates between 300-350 tons of solid wastes every day. In order to protect the hazardous effects, this large quantity of wastes requires to be managed properly. Recycling of such wastes is a challenging task in the contemporary world, especially in developing countries. This study is carried out to project the scenario of solid waste recycling pattern of Rajshahi City by using a viable and cost effective waste management technique. A detailed empirical study has been conducted in railway station area (vodra) and stadium market to collect the information about recyclable materials in recycling shops. The information about the people involved has been collected by interviewing them (scavengers, street hawkers and shopkeepers of recyclable materials) at different levels. Different recyclable wastes generated by some industries are visited in order to collecting information about the industrial involvement in the recycling practice. About 4000 people were involved in recycling practice in the city that has a great impact on the socio-economic condition in the city. There are 35 industries and organizations in which recyclable wastes are used as raw materials and reusable materials. The study shows that the most recycled items are iron, plastic and glass. Almost 17% of the total generated solid wastes is recycled everyday in the city. Therefore, present study reveals that the recycling pattern of solid wastes in Rajshahi City which can give a feed back to the City Planner and Government for taking step to improve the present status

Effect of urea fertilizer on soil, plant and food grain

The use of nitrogen fertilizer as a source of nitrogen for the growth of plant is very common in Bangladesh even all over the world. In fact the inherent supplies of readily available nutrients for Bangladesh soil are limited. The crops absorb nutrients from these insufficient supplies and the soil become exhausted. So, soil needs additional chemical fertilizers for supporting the growth and development of crops. However the accumulation pattern, recovery and losses of added chemicals in soils are of great concern in environmental pollution. A thorough investigation of accumulation of nitrogen fertilizer in soil and food-chain as well as plant has been carried out for rice crop. The soil and crop samples are collected from Bangladesh Rice Resources Institute, Rajshahi at different times of fertilization from different locations and depths. The analytical analysis for nitrogen content is carried out at environmental laboratory of Rajshahi University of Engineering and Technology. The result shows that the concentration of nitrogen in soil, plant (root, stem and leaf) and grain is much higher than the allowable limit which may create serious environmental problem and tremendous health hazard for human as well as animal

Statistical optimization of the extraction of citric acid from the solid fermented substrate of empty fruit bunches

Optimization of the process parameters for the extraction of a product from a solid substrate after bioconversion is essentially important tomaximize the yield. The extraction of citric acid from the solid substrate of oil palm empty fruit bunches (EFB) after bioconversion was initially optimized by following single factor variation. Following this, the extraction parameters were optimized statistically with the help of experimental design by Box-Behnken Design under Response Surface Methodology through the development of a second order regression model. The statistical analysis of the result showed that in the range studied all three factors, that is, shaking speed, solvent ratio, and shaking time, had a significant influence on the citric acid extraction. The highest amount of citric acid extracted was 337.34±1.1 g/kg-dry EFB, for which the extraction parameterswere a shaking speed of 125 rpm, a shaking time of 58.5 minutes, and a solvent ratio of 10.70. The coefficient of determination observed (R2) from the analysis was .9921, indicating a satisfactory fit of the model with the response. The analysis showed that all the terms of the model were highly significant with the P-value <.05

Production of citric acid from empty fruit bunches through solid state bioconversion by using rotary drum bioreactor with Aspergillus niger

The study for the production of citric acid from oil palm empty fruit bunches (EFB) by solid state bioconversion in rotary drum bioreactor using locally isolated Aspergillus niger was conducted. The optimum media content, process conditions, particle size of EFB and its distribution and bioconversion period were adopted from laboratory scale production experiments. The highest production of citric acid of 327.67±3.7 g/kg-EFB was obtained in rotary drum bioreactor with the continuous supply of saturated air of 8.4 L/min (2.8 L/kg/min) and the agitation of 90 rotation/day. The findings of the present study might contribute to the economic development by encouraging for proper management of oil palm industry biomass as well as other lignocellulosic residues

Evaluation of fungal mixed cultures for production of citric acid using empty fruit bunches by solid state bioconversion

The filamentous fungal strains of Aspergillus niger O-103A, O-109A and O-114A isolated from orange were selected for the evaluation of compatible/incompatible for the production of citric acid by mixed culture. Four combinations of O-103A and O-109A; O-103A and O-114A; O-109A and O-114A; O-103A, O-109A and O-114A were used to examine their potentiality in terms of compatible/incompatible mixed culture through citric acid production. The experiment was carried out to observe the productivity of citric acid in 250 ml Erlenmeyer flasks. The result obtained through this study showed that every culture of fungal combinations was inhibited to produce of citric acid by presence of other strain. The maximum production of citric acid obtained from the single culture of O-114A was 181.251.5 g/kg of dry EFB which was 2 times higher than the maximum production by the mixed culture of O-109A and O-114A

Statistical optimization of process parameters for the production of citric acid from oil palm empty fruit bunches

In this study, optimization of process parameters such as moisture content, incubation temperature and initial pH (fixed) for the improvement of citric acid production from oil palm empty fruit bunches through solid state bioconversion was carried out using traditional one-factor-at-a-time (OFAT) method and response surface methodology (RSM). The possible optimum level of moisture content, incubation temperature, and initial pH were found from the OFAT study to be 70%, 30 - 32oC and 5.5 - 8, respectively. The optimum moisture content of 70.3% (v/w) and incubation temperature of 33.1°C with initial pH of 6.5 gave the maximum production of citric acid (369.16 g/kg of dry EFB). The analysis of variance (ANOVA) of the statistical optimization using central composite design showed that moisture content (p<0.001) and incubation temperature (p<0.0001) as well as the interaction of these two parameters were highly significant for the citric acid production

Improvement of production of citric acid from oil palm empty fruit bunches: Optimization of media by statistical experimental designs

A sequential optimization based on statistical design and one-factor-at-a-time (OFAT) method was employed to optimize the media constituents for the improvement of citric acid production from oil palm empty fruit bunches (EFB) through solid state bioconversion using Aspergillus niger IBO-103MNB. The results obtained from the Plackett–Burman design indicated that the co-substrate (sucrose), stimulator (methanol) and minerals (Zn, Cu, Mn and Mg) were found to be the major factors for further optimization. Based on the OFAT method, the selected medium constituents and inoculum concentration were optimized by the central composite design (CCD) under the response surface methodology (RSM). The statistical analysis showed that the optimum media containing 6.4% (w/w) of sucrose, 9% (v/w) of minerals and 15.5% (v/w) of inoculum gave the maximum production of citric acid (337.94 g/kg of dry EFB). The analysis showed that sucrose (p < 0.0011) and mineral solution (p < 0.0061) were more significant compared to inoculum concentration (p < 0.0127) for the citric acid production

Development of culture inoculum for scale-up production of citric acid from oil palm empty fruit bunches by aspergillus niger

An extensive study on fungal inoculum was carried out to develop an effective culture (broth) inoculum for citric acid production from oil palm empty fruit bunches through solid state bioconversion. The effect of spores age, storage time of spore suspension inoculum, doses of spore suspension inoculum to prepare culture inoculum, ages of culture inoculum and doses of culture inoculum (concentration of biomass) on citric acid production were evaluated. It was found that the optimum age of spore was 3-4 days for the preparation of spore suspension inoculum and the maximum storage time of spore suspension inoculum was 2 days. Furthermore, the optimum dose of spore suspension inoculum was 20% (v/v) to prepare culture (broth) inoculum. The culture inoculum of 48 hrs age with biomass concentration of 0.82±0.3 g/L showed the highest production of citric acid compared to other percentage of spore suspension inoculum and culture age for all doses of culture inoculum. The highest production of citric acid of 367.4±2 g/kg-EFB was obtained with 25% (v/w) (0.21 g biomass/kg substrate) culture inoculum after 7 days of bioconversion