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Fulltext Anaerobic co-digestion of sewage sludge and food waste as a promising alternative for waste management and energy production

Hosen, MD Sabuj, Mariatul Fadzillah Mansor, Alam, MD Zahangir

Biological and Natural Resources Engineering Journal, 2019;2(1):26-46.
MyJurnal

Biogas is an economical and environmentally friendly renewable energy which can be produced by anaerobic digestion (AD). This biochemical method converts organic compounds (mainly from wastes) into a sustainable source of energy. Anaerobic co-digestion (AcoD) is a method combining more than one substrate to resolve the difficulties faced in a single substrate AD system. Solid wastes increases as the population increase so do the urbanization and industrial industries. Food waste and sewage sludge are examples of one of the solid wastes. Co-digesting of both substrates may improve process stabilization to increase biogas production and overcome the nutrients imbalance. Thus, anaerobic co-digestion has been recognized as a technology that could provide a clean renewable energy source and helps reduce the landfill problem. The objective of this paper is to investigate the recent achievements and perspectives on the interaction of co-digestion between food waste and sewage sludge to improve biogas production. This may provide valuable information on the optimization of combinations of substrates: food waste and sewage sludge and prediction of bioreactor performance.
Fulltext The potential of artificial neural network (ANN) in optimizing media constituents of citric acid production by solid state bioconversion

Ricca, R.N., Jami, Mohammed Saedi, Alam, Md. Zahangir

International Food Research Journal, 2012;19(2):491-497.
MyJurnal

This work aims at optimizing the media constituents for citric acid production from oil palm empty fruit bunches (EFB) as renewable resource using artificial neural networks (ANN) approach. The bioconversion process was done through solid state bioconversion using Aspergillus niger. ANN model was built using MATLAB software. A dataset consists of 20 runs from our previous work was used to develop ANN. The predictive and generalization ability of ANN and the results of RSM were compared. The determination coefficients (R2-value) for ANN and RSM models were 0.997 and 0.985, respectively, indicating the superiority of ANN in capturing the non-linear behavior of the system. Validation process was done and the maximum citric acid production (147.74 g/kg-EFB) was achieved using the optimal solution from ANN which consists of 6.1% sucrose, 9.2% mineral solution and 15.0% inoculum.
Liquid state bioconversion of sewage treatment plant sludge in batch fermenter and shake flask

Alam MZ, Fakhru'l-Razi A

Artif Cells Blood Substit Immobil Biotechnol, 2004;32(3):485-500.
PMID: 15508283

A study on liquid state bioconversion of sewage treatment plant (STP) sludge was assisted to evaluate the performance of batch fermenter compared to shake flask in a laboratory. Bioconversion of STP sludge was highly influenced by the mixed fungal culture of Penicillium corylophilum and Aspergillus niger after 4 days of treatment. The results showed that about 24.9 g kg(-1) dry sludge cake (DSC) was produced with enrichment of fungal biomass protein in fermenter while 20.1 g kg(-1) in shake flask after 4 days of fungal treatment. The effective biodegradation of STP sludge was recorded in both fermenter and shake flask experiment compared to control (uninnoculated sample). The results presented in this study revealed that the overall performance of fermenter in terms of sludge cake (biosolids) accumulation and biodegradation of STP sludge was higher than the shake flask.
Effect of agitation and aeration on bioconversion of domestic wastewater sludge in a batch fermenter

Alam MZ, Fakhru'l-Razi A

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2002;37(6):1087-97.
PMID: 12090282

Effects of agitation and aeration rate on microbial treatment of domestic wastewater sludge were investigated in a batch fermenter using mixed culture of Penicillium corylophilum and Aspergillus niger. It was found that liquid state bioconversion (LSB) of wastewater sludge was highly influenced by the effects of agitation and aeration. The maximum production of sludge cake and reduction of organic substances in treated sludge were recorded at 150-200 rpm of agitation speed and 0.5 vvm of aeration rate after 72 h of treatment. No effective results were observed at higher rate of agitation (300 rpm) and aeration (1.5 vvm) as compared to optimum values. The results showed that the minimum level of air saturation (pO2) was adequate to maintain the bioconversion process.
Fulltext Interaction effect of co-digestion sewage sludge and food waste for production of biogas

Hosen, Md Sabuj, Mariatul Fadzillah Mansor, Ainoor Mariana Mohd Ali, Alam, Md. Zahangir

Biological and Natural Resources Engineering Journal, 2020;3(1):37-47.
MyJurnal

Increasing population, urbanization and industrial activities have increased the amount of solid waste worldwide. Food waste (FW) and sewage sludge (SS) are some of the solid wastes. Co-digesting of both substrates may improve process stabilization to increase biogas production and overcome the nutrients imbalance. Thus, anaerobic co-digestion has been recognized as a technology that could provide a clean renewable energy source and help reducing the landfill problem. In this study, the interaction between FW and SS as co-substrates in anaerobic digestion was studied under mesophilic temperature 36C (± 0.5). The experiments were conducted using five batch reactors with different ratios of substrates. There are four different analyses used to identify the characteristics of FW and SS, which are pH, reducing sugar (RS), total solid (TS), and total carbohydrate (TC). Water displacement method was used to record biogas yield. The experimental results showed that the highest biogas yield was from the composition of 50:50 (FW: SS) with a biogas volume of 1150.14 mL, while the least was the composition of 0:100 (FW: SS) with 170.47 mL biogas produced. The results for substrate degradation showed that the composition of 100:0 (FW: SS) has the highest percentage degradation for reducing sugar with the percentage of 56%, while the minimum was 0:100 (FW: SS) with a percentage of 35%. Besides, for TC, the highest percentage of degradation was the composition 50:50 (FW: SS) with 84%, and the least was 0:100 (FW: SS) with 44%. This study proves that using FW and SS enhanced biogas production as well as reducing the current issues of waste disposal.
Enhanced settleability and dewaterability of fungal treated domestic wastewater sludge by liquid state bioconversion process

Alam MZ, Fakhru'l-Razi A

Water Res, 2003 Mar;37(5):1118-24.
PMID: 12553987

A study was conducted to evaluate the settleability and dewaterability of fungal treated and untreated sludge using liquid state bioconversion process. The fungal mixed culture of Aspergillus niger and Penicillium corylophilum was used for fungal pretreatment of wastewater sludge. The fungal strains immobilized/entrapped on sludge particles with the formation of pellets and enhanced the separation process. The results presented in this study showed that the sludge particles (pellets) size of 2-5mm of diameter were formed with the microbial treatment of sludge after 2 days of fermentation that contained maximum 33.7% of total particles with 3-3.5mm of diameter. The settling rate (measured as total suspended solids (TSS) concentration, 130 mg/l) was faster in treated sludge than untreated sludge (TSS concentration, 440 mg/l) after 1 min of settling time. In 1 min of settling operation, 86.45% of TSS was settled in treated sludge while 4.35% of TSS settled in raw sludge. Lower turbidity was observed in treated sludge as compared to untreated sludge. The results to specific resistance to filtration (SRF) revealed that the fungal inoculum had significant potentiality to reduce SRF by 99.8% and 98.7% for 1% w/w and 4% w/w of TSS sludge, respectively. The optimum fermentation period recorded was 3 days for 1% w/w sludge and 6 days for 4% w/w sludge, respectively, for dewaterability test.
Fulltext Evaluation of antioxidant capacity and physicochemical properties of Sudanese baobab (Adansonia digitata) seed- oil

Babiker, S., Mirghani, M.E.S., Saleh Matar, M., Kabbashi, N.A., Alam, Md. Z., Marikkar, J.M.N.

International Food Research Journal, 2017;24(101):0-0.
MyJurnal

The oil quality parameters of the seed oil of Baobab (Adansonia digitata) were evaluated using standard methods of analysis. The Iodine value, Peroxide value, Saponification value were 86 g/100g, 4.08 mEq/Kg, 188 mg/g, respectively, for seed oil. The oil content of the kernel was higher 23% compared to the hulls that contain 5.4% oil. The kernel oil contains substantial quantities of calcium, potassium, and magnesium, which were found to be 4116, 2339 and 1629 mg/Kg, respectively. The fatty acid profile showed that oleic and linoleic were the major unsaturated fatty acids, whereas palmitic was the major saturated acid. The oil also, showed considerable amount of total phenolic content (TPC) and worthy antioxidant activity. Baobab oil has great nutritional and industrial potentials. It is therefore recommended that more and advanced research should be undertaken for this abundant source of natural nutritious oil.
Fulltext Effect of solvent types on phenolics content and antioxidant activities of Acacia Polyacantha gum

Mirghani, M.E.S., Mohammedelnour, Ahmed A., Kabbashi, Nasser A., Alam, Md Z., Musa, Khalid H., Abdullah, Aminah.

International Food Research Journal, 2017;24(101):0-0.
MyJurnal

Acacia polyacantha gum (APG) is a dried exudate which obtained from the stems and branches of Acacia polyacantha trees. APG is rich in soluble dietary fibers as well as organic compounds. In this study quantitation of the levels of total phenolics content (TPC) and antioxidant activities were conducted using ABTS and CUPRAC assays for APG extraction using pure solvents (methanol, ethanol, acetone) and their aqueous mixtures at 50% and 100%. The antioxidant levels were evaluated by 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) radical cation deculturization and cupric iron reducing capacity in the presence of neocuproine (CUPRAC) for the evaluation of reducing power, and (TPC) was evaluated by the Folin-Ciocalteu method. The solvent Methanol (50%) gave the best extraction ratio for APG presented by highest (TPC 60.78 mg GAE/100g of DW, CUPRAC 34.65 mg TE/100g DW, and, ABTS about 37.65 mg TE/100g DW respectively), followed by ethanol 50% extract. On the other hand, pure methanol showed the lowest TPC 5.33 mg GAE/100g of DW, ABTS 10.9 mg TE/100g DW, and CUPRAC 7.80 mg TE/100g DW, values respectively. Therefore, the variation in the antioxidant capacity of extracts was possibly due to the difference of polarity, immiscibility and the nature of the APG compounds extracted using various solvents. The higher content of antioxidant activity in APG shall be useful to human health if it is properly utilized.
Fulltext Factors Associated With Psychological Outcomes Among Vaccinated and Unvaccinated Health Care Workers Against COVID-19 Infection in Bangladesh

Alam MD, Paul SK, Momi M, Ni L, Xu Y

Front Med (Lausanne), 2022;9:852922.
PMID: 35402432 DOI: 10.3389/fmed.2022.852922

BACKGROUND: Vaccination of healthcare workers (HCWs) is recommended during the COVID-19 pandemic to reduce the risk of infection for themselves and their patients, as well as to encourage their patients to get immunized. The present study aimed to investigate the psychological outcomes and associated factors among vaccinated and unvaccinated HCWs against COVID-19 infection in Bangladesh.
METHODS: From March to August 2021, an online nationwide survey was conducted with a total of 2,038 Bangladeshi HCWs. The frequency of symptoms of general health problems, depression, anxiety, stress, post-traumatic stress disorder, insomnia, and loneliness was assessed using the Bangla versions of the GHQ-12, PHQ-2, GAD-2, PSS-4, PC-PTSD-5, ISI, and UCLA-LS scales, respectively.
RESULTS: Compared with unvaccinated HCWs (n = 1,058), vaccinated HCWs (n = 980) had a statistically significant lower prevalence of general health problems (16.7 vs. 59.1%), depression (15.6 vs. 31.9%), post-traumatic stress disorder (22.3 vs. 30.8%), insomnia (23.8 vs. 64.9%), and loneliness symptoms (13.9 vs. 21.8%). Among vaccinated HCWs, females were significantly associated with a higher risk of symptoms of general health problems (AOR, 2.71; 95% CI, 0.97-7.60), anxiety (AOR, 2.17; 95% CI, 1.14-4.13), and loneliness (AOR, 2.52; 95% CI, 1.11-5.73). Except for anxiety and post-traumatic stress disorder symptoms, participants living in urban areas had a significantly lower risk of all psychological outcomes (e.g., depression: AOR, 0.43; 95% CI, 0.27-0.67; stress: AOR, 0.64; 95% CI, 0.47-0.88). Respondents who were married were significantly less likely to experience symptoms of general health problems (AOR, 0.10; 95% CI, 0.02-0.39), depression (AOR, 0.31; 95% CI, 0.22-0.82), insomnia (AOR, 0.46; 95% CI, 0.20-1.03), and loneliness (AOR, 0.31; 95% CI, 0.10-0.92). Participants who worked as doctors were significantly less chance of experiencing symptoms of general health problems (AOR, 0.18; 95% CI, 0.08-0.37), depression (AOR, 0.51; 95% CI, 0.30-0.87), and anxiety (AOR, 0.54; 95% CI, 0.37-0.78). On the other hand, unvaccinated HCWs who were 18-29 years old and had <5 years of work experience were significantly associated with a higher risk of all psychological outcomes except anxiety and insomnia symptoms (e.g., depression among 18-29 years old: AOR, 1.83; 95% CI, 0.27-2.60; stress among those with <5 years of work experience: AOR, 2.37; 95% CI, 0.93-6.07). Participants who worked as nurses were significantly more likely to suffer from depression (AOR, 1.44; 95% CI, 0.84-2.46), anxiety (AOR, 1.42; 95% CI, 0.24-1.73), and stress (AOR, 1.55; 95% CI, 0.31-0.89) symptoms. Except for anxiety and stress symptoms, respondents who worked as frontline workers and provided direct care to infected patients were the significantly higher chance of experiencing all psychological outcomes (e.g., depression among who worked as frontline workers: AOR, 2.41; 95% CI, 0.23-3.73; insomnia among those who provide direct care to infected patients: AOR, 2.60; 95% CI, 0.34-3.06). Participants who were infected with COVID-19 had a significantly less chance of experiencing symptoms of general health problems (AOR, 0.89; 95% CI, 0.65-1.22), depression (AOR, 0.66; 95% CI, 0.48-0.92), and anxiety (AOR, 0.63; 95% CI, 0.46-0.87).
CONCLUSIONS: To control the infection and improve psychological outcomes, this study suggests emphasizing the vaccinated to unvaccinated HCWs as soon as possible. They also required special attention, health-related education, and psychological support.
Fulltext Design of High Impedance Electromagnetic Surfaces for Mutual Coupling Reduction in Patch Antenna Array

Islam MT, Alam MS

Materials (Basel), 2013 Jan 07;6(1):143-155.
PMID: 28809299 DOI: 10.3390/ma6010143

A compact planar meander-bridge high impedance electromagnetic structure (MBHIES) was designed and its bandgap characteristics, mutual coupling reduction abilities were studied and compared in detail. Several parametric analyses were performed to obtain optimized design values and the transmission responses were calculated through the suspended microstrip line and waveguide simulation methods. The achieved bandgap is 2.3 GHz (2.55-4.85 GHz) with -61 dB minimum transmission coefficient level at the center frequency of 3.6 GHz. To see the effectiveness, the proposed design was inserted between a microstrip patch antenna array which operates at 3.8 GHz and whose operating bandwidth falls within the MBHIES bandgap. The surface wave suppression phenomenon was analyzed and simulated results are verified by measuring the fabricated prototypes, both are in good agreement. The configuration reduced the mutual coupling by 20.69 dB in simulation and 19.18 dB in measurement, without affecting the radiation characteristics of the array but increasing the gain slightly.
Fulltext An Appraisal of Mortality in Intensive Care Unit of a Level III Military Hospital of Bangladesh

Alam MR, Haque M, Haque M

Indian J Crit Care Med, 2017 Sep;21(9):594-598.
PMID: 28970660 DOI: 10.4103/ijccm.IJCCM_250_17

BACKGROUND: Mortalities in Intensive Care Units (ICUs) are high and widely variable. The unpredictability of death rates is attributable to age, sex, nature and severity of illness, comorbidity, well-timed medical attention, quality of the attending staffs, iatrogenic events, total management facilities, and overall grade of the ICU in general.
MATERIALS AND METHODS: A total of seventy patients who died in the ICU of a Level III Combined Military Hospital within a period of 2 years were studied in retrospect to review the mortality pattern.
RESULTS: Overall mortality rate was 3.58%, among which 81.43% were male and 18.57% were female. The mortality rate in geriatric patients was 12.26% and 2.84% in the age group of 12-60 years and 2.56% in below 12 years. The major causes of death were ischemic heart disease (20%), cerebrovascular disease (14.28%), and chronic obstructive pulmonary disease (10%). Highest incidence of death occurred during 1-3 days of ICU stay (34.28%) and the lowest was at 4 days to 1 week (4.28%).
CONCLUSION: Ischemic heart disease (IHD) is remaining as the most important cause of mortality in our community although many countries have succeeded in reducing the IHD mortality by a combination of lifestyle modification and improving the health-care delivery systems.
Fulltext Gain enhancement of a multiband resonator using defected ground surface on epoxy woven glass material

Alam MS, Islam MT, Arshad H

ScientificWorldJournal, 2014;2014:159468.
PMID: 24883354 DOI: 10.1155/2014/159468

A multiband microstrip resonator is proposed in this study which is realized through a rectangular radiator with embedded symmetrical rectangular slots in it and a defected ground surface. The study is presented with detailed parametric analyses to understand the effect of various design parameters. The design and analyses are performed using the FIT based full-wave electromagnetic simulator CST microwave studio suite. With selected parameter values, the resonator showed a peak gain of 5.85 dBi at 5.2 GHz, 6.2 dBi at 8.3 GHz, 3.9 dBi at 9.5 GHz, 5.9 dBi at 12.2 GHz, and 4.7 dBi at 14.6 GHz. Meanwhile, the main lobe magnitude and the 3 dB angular beam width are 6.2 dBi and 86°, 5.9 dBi and 53.7°, 8.5 dBi and 43.9°, 8.6 dBi and 42.1°, and 4.7 dBi and 30.1°, respectively, at the resonant frequencies. The overall resonator has a compact dimension of 0.52λ × 0.52λ × 0.027λ at the lower resonant frequency. For practical validation, a lab prototype was built on a 1.6 mm thick epoxide woven glass fabric dielectric material which is measured using a vector network analyzer and within an anechoic chamber. The comparison between the simulated and measured results showed a very good understanding, which implies the practical suitability of the proposed multiband resonator design.
Evaluation of solvent system for the enzymatic synthesis of ethanol-based biodiesel from sludge palm oil (SPO)

Nasaruddin RR, Alam MZ, Jami MS

Bioresour Technol, 2014 Feb;154:155-61.
PMID: 24384322 DOI: 10.1016/j.biortech.2013.11.095

A green technology of biodiesel production focuses on the use of enzymes as the catalyst. In enzymatic biodiesel synthesis, suitable solvent system is very essential to reduce the inhibition effects of the solvent to the enzymes. This study produced ethanol-based biodiesel from a low-cost sludge palm oil (SPO) using locally-produced Candida cylindracea lipase from fermentation of palm oil mill effluent (POME) based medium. The optimum levels of ethanol-to-SPO molar ratio and enzyme loading were found to be 4:1 and 10 U/25 g of SPO respectively with 54.4% w/w SPO yield of biodiesel and 21.7% conversion of free fatty acid (FFA) into biodiesel. Addition of tert-butanol at 2:1 tert-butanol-to-SPO molar ratio into the ethanol-solvent system increased the yield of biodiesel to 71.6% w/w SPO and conversion of FFA into biodiesel to 28.8%. The SPO and ethanol have promising potential for the production of renewable biodiesel using enzymatic-catalyzed esterification and transesterification.
Statistical optimization of process conditions for cellulase production by liquid state bioconversion of domestic wastewater sludge

Alam MZ, Muyibi SA, Wahid R

Bioresour Technol, 2008 Jul;99(11):4709-16.
PMID: 17981027

A two-level fractional factorial design (FFD) was used to determine the effects of six factors, i.e. substrate (domestic wastewater sludge - DWS) and co-substrate concentration (wheat flour - WF), temperature, initial pH, inoculum size and agitation rate on the production of cellulase enzyme by Trichoderma harzianum in liquid state bioconversion. On statistical analysis of the results from the experimental studies, optimum process conditions were found to be temperature 32.5 degrees C, substrate concentration (DWS) 0.75% (w/w), co-substrate (WF) concentration 2% (w/w), initial pH 5, inoculum size 2% (v/w) and agitation 175 rpm. Analysis of variance (ANOVA) showed a high coefficient of determination (R2) of 0.975. Cellulase activity reached 10.2 FPU/ml at day 3 during the fermentation process which indicated about 1.5-fold increase in production compared to the cellulase activity obtained from the results of design of experiment (6.9 FPU/ml). Biodegradation of DWS was also evaluated to verify the efficiency of the bioconversion process as a waste management method.
Optimization of process parameters for the bioconversion of activated sludge by Penicillium corylophilum, using response surface methodology

Mannan S, Fakhruĺ-Razi A, Alam MZ

J Environ Sci (China), 2007;19(1):23-8.
PMID: 17913149

The optimization of process parameters for the bioconversion of activated sludge by Penicillium corylophilum was investigated using response surface methodology (RSM). The three parameters namely temperature of 33 degrees C, agitation of 150 r/min, and pH of 5 were chosen as center point from the previous study of fungal treatment. The experimental data on chemical oxygen demand (COD) removal (%) were fitted into a quadratic polynomial model using multiple regression analysis. The optimum process conditions were determined by analyzing response surface three-dimensional surface plot and contour plot and by solving the regression model equation with Design Expert software. Box-Behnken design technique under RSM was used to optimize their interactions, which showed that an incubation temperature of 32.5 degrees C, agitation of 105 r/min, and pH of 5.5 were the best conditions. Under these conditions, the maximum predicted yield of COD removal was 98.43%. These optimum conditions were used to evaluate the trail experiment, and the maximum yield of COD removal was recorded as 98.5%.
Treatment and biodegradation kinetics of microbially treated domestic wastewater sludge

Alam MZ, Fakhru'l-Razi A, Molla AH

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2004;39(8):2059-70.
PMID: 15332668

A laboratory-scale study was undertaken to evaluate the liquid state bioconversion (LSB) in terms of biodegradation of microbially treated domestic wastewater sludge (biosolids) as well as its kinetics. The potential fungal strains and process factors developed from previous studies were used throughout the study. The results presented in this study showed that an effective biodegradation occurred with the biosolids (sludge cake) accumulated. The maximum biosolids (sludge cake) accumulated (93.8 g/kg of liquid sludge) enriched with the biomass protein (30.2 g/kg of dry biosolids), was achieved which improved the effluent quality by enhancing the removal of chemical oxygen demand (COD), reducing sugar (RS), soluble protein (SP), total dissolved solids (TDS), and total suspended solids (TSS). The higher reduction of specific resistance to filtration (SRF) was observed during bioconversion process. The kinetics results showed that the experimental data were better fitted for the biodegradation efficiency, and biosolids accumulation and biodegradation rate.
Solid state bioconversion of oil palm biomass for ligninase enzyme production

Alam MZ, Mahmat ME, Muhammad N

Artif Cells Blood Substit Immobil Biotechnol, 2005;33(4):457-66.
PMID: 16317964

A laboratory-scale study of bioconversion of local lignocellulosic material, oil palm biomass (OPB) was conducted by evaluating the enzyme production through microbial treatment in solid state bioconversion (SSB). OPB in the form of empty fruit bunches (EFB) was used as a solid substrate and treated with the white-rot fungus, Phanerochaete chrysosporium, to produce ligninase. The results showed that the highest ligninase activity of 400.27 U/liter was obtained at day 12 of fermentation. While the optimum study indicated the enzyme production of 1472.8 U/liter with moisture content of 50%, 578.7 U/liter with 10% v/w of inoculum size, and 721.8 U/liter with co-substrate concentration of 1% (w/w) at days 9, 9 and 12 of fungal treatment, respectively. The parameters glucosamine and reducing sugar were observed to evaluate the growth and substrate utilization in the experiment.
Evaluation of fungal potentiality for bioconversion of domestic wastewater sludge

Alam MZ, Fakhru'l-Razi A, Molla AH

J Environ Sci (China), 2004;16(1):132-7.
PMID: 14971468

This study was undertaken to screen the filamentous fungi isolated from its relevant habitats(wastewater, sewage sludge and sludge cake) for the bioconversion of domestic wastewater sludge. A total of 35 fungal strains were tested against wastewater sludge (total suspended solids, TSS 1%-5% w/w) to evaluate its potentiality for enhancing the biodegradability and dewaterability using liquid state bioconversion(LSB) process. The strains were divided into five groups i.e. Penicillium, Aspergillus, Trichoderma, Basidiomycete and Miscellaneous, respectively. The strains WWZP1003, SCahmA103, SCahmT105 and PC-9 among their respective groups of Penicillium, Aspergillus, Trichoderma and Basidiomycete played potential roles in terms of separation (formation of pellets/flocs/filaments), biodegradation(removal of COD) and filtration (filterability) of treated domestic wastewater sludge. The Miscellaneous group was not considered due to its unsatisfactory results as compared to the other groups. The pH value was also influenced by the microbial treatment during fermentation process. The filterability of treated sludge was improved by fungal treatment, and lowest filtration time was recorded for the strain WWZP1003 and SCahmA103 of Penicillium and Aspergillus groups respectively compared with other strains.
Fulltext COVID-19 outbreak and sectoral performance of the Australian stock market: An event study analysis

Alam MM, Wei H, Wahid ANM

Aust Econ Pap, 2020 Nov 27.
PMID: 33349733 DOI: 10.1111/1467-8454.12215

The outbreak of COVID-19 has weakened the economy of Australia and its capital market since early 2020. The overall stock market has declined. However, some sectors become highly vulnerable while others continue to perform well even in the crisis period. Given this new reality, we seek to investigate the initial volatility and the sectoral return. In this study, we analyse data for eight sectors such as, transportation, pharmaceuticals, healthcare, energy, food, real estate, telecommunications and technology of the Australian stock market. In doing so, we obtain data from Australian Securities Exchange (ASX) and analysed them based on 'Event Study' method. Here, we use the 10-days window for the event of official announcement of the COVID-19 outbreak in Australia on 27 February 2020. The findings of the study show that on the day of announcement, the indices for food, pharmaceuticals and healthcare exhibit impressive positive returns. Following the announcement, the telecommunications, pharmaceuticals and healthcare sectors exhibit good performance, while poor performance is demonstrated by the transportation industry. The findings are vital for investors, market participants, companies, private and public policymakers and governments to develop recovery action plans for vulnerable sectors and enable investors to regain their confidence to make better investment decisions.
Use of fungi to improve bioconversion of activated sludge

Mannan S, Fakhru'l-Razi A, Alam MZ

Water Res, 2005 Aug;39(13):2935-43.
PMID: 16000208

The present study was designed to evaluate the potential of microbial adaptation and its affinity to biodegradation as well as bioconversion of soluble/insoluble (organic) substances of domestic wastewater treatment plant (DWTP) sludge (activated domestic sludge) under natural/non-sterilized conditions. The two filamentous fungi, Penicillium corylophilum (WWZP1003) and Aspergillus niger (SCahmA103) were used to achieve the objectives. It was observed that P. corylophilum (WWZP1003) was the better strain compared to A. niger (SCahmA103) for the bioconversion of domestic activated sludge through adaptation. The visual observation in plate culture showed that about 95-98% of cultured microbes (P. corylophilum and A. niger) dominated in treated sludge after 2 days of treatment. In this study, it was also found that the P. corylophilum was capable of removing 94.40% of COD and 98.95% of turbidity of filtrate with minimum dose of inoculum of 10% v/v in DWTP sludge (1% w/w). The pH level was lower (acidic condition) in the fungal treatment and maximum reduction of COD and turbidity was observed (at lower pH). The results for specific resistance to filtration (SRF) showed that the fungi played a great role in enhancing the dewaterability and filterability. In particular, the strain Penicillium had a more significant capability (than A. niger) of reducing 93.20% of SRF compared to the uninoculated sample. Effective results were observed by using fungal inoculum after 2 days of treatment. The developed LSB process is a new biotechnological approach for sludge management strategy.

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