Displaying publications 1 - 20 of 43 in total

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  1. Nuid M, Aris A, Krishnen R, Chelliapan S, Muda K
    J Environ Manage, 2023 Oct 15;344:118501.
    PMID: 37418913 DOI: 10.1016/j.jenvman.2023.118501
    This study was to develop biogranules using a sequencing batch reactor (SBR) and to evaluate the effect of pineapple wastewater (PW) as a co-substrate for treating real textile wastewater (RTW). The biogranular system cycle was 24 h (2 stages of phase), with an anaerobic phase (17.8 h) followed by an aerobic phase (5.8 h) for every stage of the phase. The concentration of pineapple wastewater was the main factor studied in influencing COD and color removal efficiency. Pineapple wastewater with different concentrations (7, 5, 4, 3, and 0% v/v) makes a total volume of 3 L and causes the OLRs to vary from 2.90 to 0.23 kg COD/m3day. The system achieved 55% of average color removal and 88% of average COD removal at 7%v/v PW concentration during treatment. With the addition of PW, the removal increased significantly. The experiment on the treatment of RTW without any added nutrients proved the importance of co-substrate in dye degradation.
  2. Yusoff HM, Ahmad H, Ismail H, Reffin N, Chan D, Kusnin F, et al.
    Hum Resour Health, 2023 Oct 13;21(1):82.
    PMID: 37833727 DOI: 10.1186/s12960-023-00868-8
    Violence against healthcare workers recently became a growing public health concern and has been intensively investigated, particularly in the tertiary setting. Nevertheless, little is known of workplace violence against healthcare workers in the primary setting. Given the nature of primary healthcare, which delivers essential healthcare services to the community, many primary healthcare workers are vulnerable to violent events. Since the Alma-Ata Declaration of 1978, the number of epidemiological studies on workplace violence against primary healthcare workers has increased globally. Nevertheless, a comprehensive review summarising the significant results from previous studies has not been published. Thus, this systematic review was conducted to collect and analyse recent evidence from previous workplace violence studies in primary healthcare settings. Eligible articles published in 2013-2023 were searched from the Web of Science, Scopus, and PubMed literature databases. Of 23 included studies, 16 were quantitative, four were qualitative, and three were mixed method. The extracted information was analysed and grouped into four main themes: prevalence and typology, predisposing factors, implications, and coping mechanisms or preventive measures. The prevalence of violence ranged from 45.6% to 90%. The most commonly reported form of violence was verbal abuse (46.9-90.3%), while the least commonly reported was sexual assault (2-17%). Most primary healthcare workers were at higher risk of patient- and family-perpetrated violence (Type II). Three sub-themes of predisposing factors were identified: individual factors (victims' and perpetrators' characteristics), community or geographical factors, and workplace factors. There were considerable negative consequences of violence on both the victims and organisations. Under-reporting remained the key issue, which was mainly due to the negative perception of the effectiveness of existing workplace policies for managing violence. Workplace violence is a complex issue that indicates a need for more serious consideration of a resolution on par with that in other healthcare settings. Several research gaps and limitations require additional rigorous analytical and interventional research. Information pertaining to violent events must be comprehensively collected to delineate the complete scope of the issue and formulate prevention strategies based on potentially modifiable risk factors to minimise the negative implications caused by workplace violence.
  3. Nuid M, Aris A, Abdullah S, Fulazzaky MA, Muda K
    J Environ Manage, 2023 Sep 01;341:118032.
    PMID: 37163834 DOI: 10.1016/j.jenvman.2023.118032
    Biogranulation technology is an emerging biological process in treating various wastewater. However, the development of biogranules requires an extended period of time when treating wastewaters with high oil and grease (O&G) content. A study was therefore conducted to assess the formation of biogranules through bioaugmentation with the Serratia marcescens SA30 strain, in treating real anaerobically digested palm oil mill effluent (AD-POME), with O&G of about 4600 mg/L. The biogranules were developed in a lab-scale sequencing batch reactor (SBR) system under alternating anaerobic and aerobic conditions. The experimental data were assessed using the modified mass transfer factor (MMTF) models to understand the mechanisms of biosorption of O&G on the biogranules. The system was run with variable organic loading rates (OLR) of 0.69-9.90 kg/m3d and superficial air velocity (SAV) of 2 cm/s. After 60 days of being bioaugmented with the Serratia marcescens SA30 strain, the flocculent biomass transformed into biogranules with excellent settleability with improved treatment efficiency. The biogranules showed a compact structure and good settling ability with an average diameter of about 2 mm, a sludge volume index at 5 min (SVI5) of 43 mL/g, and a settling velocity (SV) of 81 m/h after 256 days of operation. The average removal efficiencies of O&G increased from 6 to 99.92%, respectively. The application of the MMTF model verified that the resistance to O&G biosorption is controlled via film mass transfer. This research indicates successful bioaugmentation of biogranules using the Serratia marcescens SA30 strain for enhanced biodegradation of O&G and is capable to treat real AD-POME.
  4. Daud SM, Noor ZZ, Mutamim NSA, Baharuddin NH, Aris A
    Environ Sci Pollut Res Int, 2023 Aug;30(40):91636-91648.
    PMID: 37518846 DOI: 10.1007/s11356-023-28975-y
    A conventional activated sludge (CAS) system has traditionally been used for secondary treatment in wastewater treatment plants. Due to the high cost of aeration and the problem of sludge treatment, researchers are developing alternatives to the CAS system. A membrane bioreactor (MBR) is a technology with higher solid-liquid separation efficiency. However, the use of MBR is limited due to inevitable membrane fouling and high energy consumption. Membrane fouling requires frequent cleaning, and MBR components must be replaced, which reduces membrane lifetime and operating costs. To overcome the limitations of the MBR system, a microbial fuel cell-membrane bioreactor (MFC-MBR) coupling system has attracted the interest of researchers. The design of the novel bioelectrochemical membrane reactor (BEMR) can effectively couple microbial degradation in the microbial electrochemical system (MES) and generate a microelectric field to reduce and alleviate membrane fouling in the MBR system. In addition, the coupling system combining an MES and an MBR can improve the efficiency of COD and ammonium removal while generating electricity to balance the energy consumption of the system. However, several obstacles must be overcome before the MFC-MBR coupling system can be commercialised. The aim of this study is to provide critical studies of the MBR, MES and MFC-MBR coupling system for wastewater treatment. This paper begins with a critical discussion of the unresolved MBR fouling problem. There are detailed past and current studies of the MES-MBR coupling system with comparison of performances of the system. Finally, the challenges faced in developing the coupling system on a large scale were discussed.
  5. Asadi K, Tehrany PM, Salari A, Ghorbani Vajargah P, Mollaei A, Sarafi M, et al.
    Int Wound J, 2023 Jul 10.
    PMID: 37424390 DOI: 10.1111/iwj.14300
    The goal of this systematic review and meta-analysis is to provide an overview of the prevalence of surgical wound infection and related factors in patients after long bone surgery. A comprehensive, systematic search was conducted in different international electronic databases, such as Scopus, PubMed, Web of Science and Persian electronic databases such as Iranmedex and Scientific Information Database using keywords extracted from Medical Subject Headings such as "Prevalence", "Surgical wound infection", "Surgical site infection" and "Orthopedics" from the earliest to the May 1, 2023. The appraisal tool for cross-sectional studies (AXIS tool) evaluates the quality of the included studies. A total of 71 854 patients undergoing long bone surgery participated in 12 studies. The pooled prevalence of surgical wound infection in patients who underwent long bone surgery reported in the 12 studies was 3.3% (95% CI: 1.5%-7.2%; I2  = 99.39%; p 
  6. Aziz MA, Norman S, Mohamed Zaid S, Simarani K, Sulaiman R, Mohd Aris A, et al.
    Arch Microbiol, 2023 Jan 28;205(2):76.
    PMID: 36708390 DOI: 10.1007/s00203-023-03417-y
    Wastewater monitoring for SARS-CoV-2 has attracted considerable attention worldwide to complement the existing clinical-based surveillance system. In this study, we report our first successful attempt to prove the circulation of SARS-CoV-2 genes in Malaysian urban wastewater. A total of 18 wastewater samples were obtained from a regional sewage treatment plant that received municipal sewage between February 2021 and May 2021. Using the quantitative PCR assay targeting the E and RdRp genes of SARS-CoV-2, we confirmed that both genes were detected in the raw sewage, while no viral RNA was found in the treated sewage. We were also able to show that the trend of COVID-19 cases in Kuala Lumpur and Selangor was related to the changes in SARS-CoV-2 RNA levels in the wastewater samples. Overall, our study highlights that monitoring wastewater for SARS-CoV-2 should help local health professionals to obtain additional information on the rapid and silent circulation of infectious agents in communities at the regional level.
  7. Mohd Zainudin NAI, Abd Murad NB, Aris A, Hussain NH
    Plant Dis, 2022 Sep 19.
    PMID: 36122197 DOI: 10.1094/PDIS-06-22-1291-PDN
    In July 2019 to November 2021, symptoms of fruit rot of Averrhoa bilimbi (commonly known as bilimbi) fruits were observed in Serdang (3°00'05.8"N 101°42'18.4"E) and Tanjong Karang (3°25'55.3"N 101°12'55.7"E), Selangor, Malaysia. External decay showed some yellowish to brownish-red discoloration and inside the fruit there was black powdery sporulation and a brownish decay that measured between 8 - 15 mm wide. Twenty random symptomatic fruits were collected from each location. Small pieces (5 mm) of infected tissues from the fruit rot were surface sterilized for 1 min in 0.5% NaOCl, washed twice with sterile distilled water and cultured onto potato dextrose agar (PDA) and peptone pentachloronitrobenzene agar (PPA). The plates were incubated at 28 ± 1oC under 12 hours light/dark for 7 days. The fungal colonies growing from the plates were purified using hyphal tip technique (Leyronas et al. 2012). A total of 42 fungal isolates were obtained, and the morphology characteristics of six isolates were matched that of Aspergillus niger. The A. niger isolates were further identified based genus and species-specific Internal Transcribed Spacer (ITS) sequencing. Primers ITS1/ITS4, were used to amplify and subsequently sequenced the ITS1-5.8S-ITS2 region (White et al. 1990). Primer ASAP1 (5'-CAGCGAGTACATCACCTTGG-3'), ASAP2 (5'-CCATTGTTGAAAGTTTTAACTGATT-3') was used for Aspergillus species confirmation, primer ASPU (5'-ACTACCGATTGAATGGCTCG-3') / Ni1r (5'-ACGCTTTCAGACAGTGTTCG-3') for A. niger species-specific, ASPU / Af3r (5'-CATACTTTCAGAACAGCGTTCA-3') for A. fumigatus specific-specific and ASPU / Fl2r (5'-TTCACTAGATCAGACAGAGT-3') for A. flavus specific-specific (Sugita et al. 2004). In general, Aspergillus niger isolates grew rapidly on PDA and were visibly white initially then appearing black and powdery on the second day of incubation (Figure 1A). Some isolates grew rapidly (0.71-0.85 cm/day) and have a cottony appearance. The conidia were appeared brown to black, globose and rough with diameter ranging between 4.1-5.2 µm (Figure 1B). The vesicles were hyaline, globose, and brown in color with measurement of 30-75 µm in diameter with uniseriate sterigmata (Figure 1C). The conidial head was brownish black in color and split into several irregular and regular columns of conidial chains (Figure 1D-E). The conidiophores were hyaline, and brown in color. Phylogenetic trees of ITS (Figure 2A) and ASAP sequences (Figure 2B) were constructed using a Neighbor-Joining method showing isolates Aspergillus niger #11, #15, #32, #33, #41 and #42 were grouped into the same clade as A. niger (accession no. MT446087). To examine virulence of A. niger, pathogenicity tests were performed three times by inoculating an asymptomatic fruit with six isolates of A. niger (isolate #11, #15, #32, #33, #41 and #42) and a single isolate for each species of Aspergillus aculeatus, Lasiodiplodia theobromae and Penicillium gerundense. Ten fruits were inoculated by placing a mycelial disc (6 mm) (Kouame et al. 2010) from a 5-day-old culture of each fungal colony while control fruits were non-inoculated with any fungal colony (10 fruits were inoculated with a sterile agar disc and 10 were non-inoculated, respectively). After 3 days, typical symptoms of Aspergillus fruit rot were observed on A. niger inoculated fruits, whereas the control fruits remained asymptomatic (Figure 1F-P). Aspergillus niger was reisolated and reidentified based on morphological and molecular characterization from the inoculated, symptomatic fruits, thus confirming Koch's postulates. A. niger causing widespread diseases in various plant and it is a common contaminant of food. This study shows A. niger to be highly virulent on bilimbi fruits and leads to reduction of fruit quality and its production. To our knowledge, this is the first report of A. niger causing fruit rot on bilimbi and future work on its pathogenesis may provide strategies for disease control against the pathogen.
  8. Chen CX, Aris A, Yong EL, Noor ZZ
    Environ Sci Pollut Res Int, 2022 Jan;29(4):4787-4802.
    PMID: 34775565 DOI: 10.1007/s11356-021-17365-x
    Many advanced technologies have shown encouraging results in removing antibiotics from domestic wastewater. However, as activated sludge treatment is the most common sewage treatment system employed worldwide, improving its effect on antibiotic removal would be more desirable. Understanding the removal mechanisms, kinetics and factors that affect antibiotic removal in the activated sludge process is important as it would allow us to improve the treatment performance. Although these have been discussed in various literature covering different types of antibiotics and wastewater, a specific review on antibiotics and domestic wastewater is clearly missing. This review paper collates, discusses and analyses the removal of antibiotics from sewage in the activated sludge process along with the removal mechanisms and kinetics. The antibiotics are categorised into six classes: β-lactam, dihydrofolate reductase inhibitor, fluoroquinolone, macrolide, sulfonamides and tetracycline. Furthermore, the factors affecting the system performance with regard to antibiotic removal are examined.
  9. Aris A, Sulaiman S, Che Hasan MK
    Enferm Clin, 2021 04;31 Suppl 2:S10-S15.
    PMID: 33849138 DOI: 10.1016/j.enfcli.2020.10.006
    This study aimed to investigate the effects of music on physiological outcomes for post-operative TKA patients in the recovery unit. Fifty-six patients from Hospital Melaka were randomized equally into intervention (IG) and control groups (CG). IG received the usual care and listened to selected music for 60min, while the CG received only the usual care. Systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), respiration rate (RR) and oxygen saturation (SpO2) were measured on arrival and after 10, 20, 30, and 60min in the recovery unit. A significant difference between groups was observed in RR upon arrival (U=276.5, p=0.029) and after 10min (U=291, p=0.45). Meanwhile, there were significant differences in DBP (F=3.158, p=0.032), RR (χ2=15.956, p=0.003) and SpO2 (χ2=14.084, p=0.007) over time in the IG. Overall, listening to music immediately after TKA has an effect on DBP, RR, and SpO2.
  10. We ACE, Aris A, Zain NAM, Muda K, Sulaiman S
    Chemosphere, 2021 Jan;263:128209.
    PMID: 33297168 DOI: 10.1016/j.chemosphere.2020.128209
    The present work investigates the feasibility of aerobic granulation for the treatment of low-medium strength domestic wastewater for long-term operation and effects of a static mixer on the properties and removal performances of the aerobic granules formed. The static mixer was installed in a sequential batch reactor to provide higher hydrodynamic shear force in enhancing the formation of the aerobic granules. Aerobic granules were successfully formed in the domestic wastewater, and the granulation treatment system was sustained for a period of 356 days without granules disintegration. Subsequent to the installation, aerobic granules with a low SVI30 of 41.37 mL/gTSS, average diameter 1.11 mm, granular strength with integrity coefficient 10.4% and regular shape with minimum filamentous outgrowth were formed. Mineral concentrations such as Fe, Mg, Ca and Na as well as composition of protein and polysaccharide in tightly bound-extracellular polymeric substance of the aerobic granules were found to be higher under the effect of the static mixer. However, no significant improvement was observed on the TCOD, NH4+-N and TSS removal performance. Good TCOD and TSS removal performance of above 85% and 90%, respectively and moderate NH4+-N removal performance of about 60% were observed throughout the study. Higher simultaneous nitrification and denitrification (SND) efficiency of 56% was observed after the installation of the static mixer, as compared to 21% prior. Therefore, it may be concluded that the installation of the static mixer significantly improved the properties of aerobic granules formation and SND efficiency but not the TCOD, NH4+-N and TSS removal performance.
  11. Hasan ZAE, Mohd Zainudin NAI, Aris A, Ibrahim MH, Yusof MT
    J Appl Microbiol, 2020 Oct;129(4):991-1003.
    PMID: 32324939 DOI: 10.1111/jam.14674
    AIMS: Agro-based wastes were evaluated as a medium for mass micropropagule production and optimal efficacy of Trichoderma asperellum B1092 in controlling Fusarium oxysporum f. sp. lycopersici and promoting tomato growth. This study focused on biological control because pathogen persistence in the soil makes the disease difficult to control.

    METHODS AND RESULTS: Rice bran, biochar, empty fruit bunches, coconut fibres, compost, top soil and mixed soil were evaluated as media for mass multiplication of T. asperellum, which is effective in controlling plant pathogens. Yielding the most colony forming units (CFU) among the media, coconut fibre was deemed most suitable for promoting sporulation. After 120 days on the medium, T. asperellum B1902 produced 9·053 × 105  CFU per gram coconut fibre; oil palm empty fruit bunches was second highest (7·406 × 105  CFU per gram). In field tests of T. asperellum B1092 against F. oxysporum f. sp lycopersici (causing Fusarium wilt of cherry tomato), B1092 significantly promoted plant growth compared to the control. The efficacy of this formulation resulted in increased growth of roots and shoots tomato plants and total lycopene, sugar, K, N, Ca, P and Mg content after 120 days.

    CONCLUSIONS: Trichoderma asperellum B1092 showed great field potential for improving productivity and quality of tomatoes and in controlling Fusarium wilt of cherry tomato.

    SIGNIFICANCE AND IMPACT OF THE STUDY: This innovative approach using a cheap agro-waste to control the persistent soil-borne Fusarium pathogen of cherry tomato should increase soil survival rate of Trichoderma and has potential for upscaling in the field for other crops.

  12. How SW, Sin JH, Wong SYY, Lim PB, Mohd Aris A, Ngoh GC, et al.
    Water Sci Technol, 2020 Jan;81(1):71-80.
    PMID: 32293590 DOI: 10.2166/wst.2020.077
    Many developing countries, mostly situated in the tropical region, have incorporated a biological nitrogen removal process into their wastewater treatment plants (WWTPs). Existing wastewater characteristic data suggested that the soluble chemical oxygen demand (COD) in tropical wastewater is not sufficient for denitrification. Warm wastewater temperature (30 °C) in the tropical region may accelerate the hydrolysis of particulate settleable solids (PSS) to provide slowly-biodegradable COD (sbCOD) for denitrification. This study aimed to characterize the different fractions of COD in several sources of low COD-to-nitrogen (COD/N) tropical wastewater. We characterized the wastewater samples from six WWTPs in Malaysia for 22 months. We determined the fractions of COD in the wastewater by nitrate uptake rate experiments. The PSS hydrolysis kinetic coefficients were determined at tropical temperature using an oxygen uptake rate experiment. The wastewater samples were low in readily-biodegradable COD (rbCOD), which made up 3-40% of total COD (TCOD). Most of the biodegradable organics were in the form of sbCOD (15-60% of TCOD), which was sufficient for complete denitrification. The PSS hydrolysis rate was two times higher than that at 20 °C. The high PSS hydrolysis rate may provide sufficient sbCOD to achieve effective biological nitrogen removal at WWTPs in the tropical region.
  13. Aris A, Khalid MZM, Yahaya H, Yoong LO, Ying NQ
    Curr Diabetes Rev, 2020;16(4):387-394.
    PMID: 31433762 DOI: 10.2174/1573399815666190712192527
    BACKGROUND: Type 2 diabetes (T2D) is a preventable condition. Targeting those who are at risk of getting this disease is essential.

    OBJECTIVE: To examine T2D risk among university students in Malaysia and determine its relationship with socio-demographic characteristics and physical activity.

    METHODS: The study was conducted cross-sectionally on 390 students selected using quota sampling method from 13 faculties in Universiti Kebangsaan Malaysia. A short form of the International Physical Activity Questionnaire and Finnish Diabetes Risk Score were used to measure the physical activity and T2D risk.

    RESULTS: The T2D risk was found to be low (M = 5.23, SD = 3.32) with more than two-third of the student population at the low risk level while a significant proportion of 23.8%, 5.6% and 0.3% having slightly elevated, moderate and high risk respectively. The T2D risk was significantly related to their age (rho = 0.197, p < 0.000), gender (U = 12641, p = 0.011), ethnic group (Χ2 = 18.86, p < 0.000), marital status (Χ2 = 6.597, p = 0.037), residence (U = 10345, p = 0.008), academic year (Χ2 = 14.24, p = 0.007) and physical activity (rho = -0.205, p < 0.000 and Χ2 = 13.515, p = 0.001). Of these, only age (β=0.130) and physical activity (β=-0.159) remained significant in the regression analysis.

    CONCLUSION: The findings call for a radical change in the nursing practice to target the amendable factors that are significant in order to prevent the progression of the risk towards type 2 diabetes.
  14. Mohd-Aris A, Muhamad-Sofie MHN, Zamri-Saad M, Daud HM, Ina-Salwany MY
    Vet World, 2019 Nov;12(11):1806-1815.
    PMID: 32009760 DOI: 10.14202/vetworld.2019.1806-1815
    Fish diseases are often caused either by bacteria, viruses, fungi, parasites, or a combination of these pathogens. Of these, bacterial fish diseases are considered to be a major problem in the aquaculture industry. Hence, the prevention of such diseases by proper vaccination is one of the integral strategies in fish health management, aimed at reducing the fish mortality rate in the aquaculture farms. Vaccination offers an effective yet low-cost solution to combat the risk of disease in fish farming. An appropriate vaccination regime to prevent bacterial diseases offers a solution against the harmful effects of antibiotic applications. This review discusses the role of live-attenuated vaccine in controlling bacterial diseases and the development of such vaccines and their vaccination strategy. The current achievements and potential applications of live-attenuated and combined vaccines are also highlighted. Vaccine development is concluded to be a demanding process, as it must satisfy the requirements of the aquaculture industry.
  15. Aris A, Sulaiman S, Che Hasan MK
    Enferm Clin, 2019 09;29 Suppl 2:16-23.
    PMID: 31208927 DOI: 10.1016/j.enfcli.2019.04.004
    OBJECTIVE: The objective of this study was to investigate whether music therapy affects immediate postoperative well-being among patients who had undergone TKA surgery in the recovery unit.

    METHOD: A randomized controlled trial was conducted recruiting patients from Hospital Melaka, Malaysia. Postoperative TKA patients with good hearing and visual acuity, fully conscious and prescribed with patients controlled analgesia (PCA) were randomized to either intervention or control groups using a sealed envelope. Patients in the intervention group received usual care with additional music therapy during recovery, while patients in the control group received the usual care provided by the hospital. Two factors identified affecting mental well-being were the pain (measured using numerical rating scale) and anxiety (measured using a visual analog scale) at five different minutes' points (0, 10, 20, 30, and 60).

    RESULTS: A total of 56 (control: 28, intervention: 28) postoperative TKA patients consented in the study. There was no difference in baseline characteristics between the two groups (p>0.05). Using Mann-Whitney U tests, patients in music therapy group showed significantly lower numerical pain score at 60min (p=0.045) whereas there was no significant difference between the two groups at all time points for anxiety scores (p>0.05). In the intervention group, Friedman tests showed that there was a significant difference in numerical pain (χ2=36.957, df=4, p<0.001) and anxiety score across times (χ2=18.545, p=0.001).

    CONCLUSIONS: This study found that pain score decreases over time among patients in the music therapy group while no effect is seen for anxiety. It is suggested that music therapy could not affect postoperative TKA patients' mental well-being. Nonetheless, patients reported better pain score despite the small sample.

  16. Tee SK, Ong TL, Aris A, See SML, Leong HY, Khalid MKNM, et al.
    Seizure, 2019 Apr;67:78-81.
    PMID: 30947044 DOI: 10.1016/j.seizure.2019.03.012
  17. Tariq FS, Samsuri AW, Karam DS, Aris AZ, Jamilu G
    Environ Monit Assess, 2019 Mar 21;191(4):232.
    PMID: 30900076 DOI: 10.1007/s10661-019-7359-6
    This study was conducted to determine the effects of rice husk ash (RHA) and Fe-coated rice husk ash (Fe-RHA) on the bioavailability and mobility of As, Cd, and Mn in mine tailings. The amendments were added to the tailings at 0, 5, 10, or 20% (w/w) and the mixtures were incubated for 0, 7, 15, 30, 45, and 60 days. The CaCl2 extractable As, Cd, and Mn in the amended tailings were determined at each interval of incubation period. In addition, the tailings mixture was leached with simulated rain water (SRW) every week from 0 day (D 0) until day 60 (D 60). The results showed that both RHA and Fe-RHA application significantly decreased the CaCl2-extractable Cd and Mn but increased that of As in the tailings throughout the incubation period. Consequently, addition of both RHA and Fe-RHA leached out higher amount of As from the tailings but decreased Cd and Mn concentration compared to the controls. The amount of As leached from the Fe-RHA-amended tailings was less than that from RHA-amended tailings. Application of both RHA and Fe-RHA could be an effective way in decreasing the availability of cationic heavy metals (Cd and Mn) in the tailings but these amendments could result in increasing the availability of anionic metalloid (As). Therefore, selection of organic amendments to remediate metal-contaminated tailings must be done with great care because the outcomes might be different among the elements.
  18. Ina-Salwany MY, Al-Saari N, Mohamad A, Mursidi FA, Mohd-Aris A, Amal MNA, et al.
    J Aquat Anim Health, 2019 03;31(1):3-22.
    PMID: 30246889 DOI: 10.1002/aah.10045
    Current growth in aquaculture production is parallel with the increasing number of disease outbreaks, which negatively affect the production, profitability, and sustainability of the global aquaculture industry. Vibriosis is among the most common diseases leading to massive mortality of cultured shrimp, fish, and shellfish in Asia. High incidence of vibriosis can occur in hatchery and grow-out facilities, but juveniles are more susceptible to the disease. Various factors, particularly the source of fish, environmental factors (including water quality and farm management), and the virulence factors of Vibrio, influence the occurrence of the disease. Affected fish show weariness, with necrosis of skin and appendages, leading to body malformation, slow growth, internal organ liquefaction, blindness, muscle opacity, and mortality. A combination of control measures, particularly a disease-free source of fish, biosecurity of the farm, improved water quality, and other preventive measures (e.g., vaccination) might be able to control the infection. Although some control measures are expensive and less practical, vaccination is effective, relatively cheap, and easily implemented. In this review, the latest knowledge on the pathogenesis and control of vibriosis, including vaccination, is discussed.
  19. Fulazzaky MA, Nuid M, Aris A, Muda K
    Environ Technol, 2018 Sep;39(17):2151-2161.
    PMID: 28675960 DOI: 10.1080/09593330.2017.1351494
    Understanding of mass transfer kinetics is important for biosorption of nitrogen compounds from palm oil mill effluent (POME) to gain a mechanistic insight into future biological processes for the treatment of high organic loading wastewater. In this study, the rates of global and sequential mass transfer were determined using the modified mass transfer factor equations for the experiments to remove nitrogen by aerobic granular sludge accumulation in a sequencing batch reactor (SBR). The maximum efficiencies as high as 97% for the experiment run at [kLa]g value of 1421.8 h-1 and 96% for the experiment run at [kLa]g value of 9.6 × 1037 h-1 were verified before and after the addition of Serratia marcescens SA30, respectively. The resistance of mass transfer could be dependent on external mass transfer that controls the transport of nitrogen molecule along the experimental period of 256 days. The increase in [kLa]g value leading to increased performance of the SBR was verified to contribute to the future applications of the SBR because this phenomenon provides new insight into the dynamic response of biological processes to treat POME.
  20. How SW, Lim SY, Lim PB, Aris AM, Ngoh GC, Curtis TP, et al.
    Water Sci Technol, 2018 May;77(9-10):2274-2283.
    PMID: 29757179 DOI: 10.2166/wst.2018.143
    Intensive aeration for nitrification is a major energy consumer in sewage treatment plants (STPs). Low-dissolved-oxygen (low-DO) nitrification has the potential to lower the aeration demand. However, the applicability of low-DO nitrification in the tropical climate is not well-understood. In this study, the potential of low-DO nitrification in tropical setting was first examined using batch kinetic experiments. Subsequently, the performance of low-DO nitrification was investigated in a laboratory-scale sequential batch reactor (SBR) for 42 days using real tropical sewage. The batch kinetic experiments showed that the seed sludge has a relatively high oxygen affinity. Thus, the rate of nitrification was not significantly reduced at low DO concentrations (0.5 mg/L). During the operation of the low-DO nitrification SBR, 90% of NH4-N was removed. The active low-DO nitrification was mainly attributed to the limited biodegradable organics in the sewage. Fluorescence in-situ hybridisation and 16S rRNA amplicon sequencing revealed the nitrifiers were related to Nitrospira genus and Nitrosomonadaceae family. Phylogenetic analysis suggests 47% of the operational taxonomic units in Nitrospira genus are closely related to a comammox bacteria. This study has demonstrated active low-DO nitrification in tropical setting, which is a more sustainable process that could significantly reduce the energy footprint of STPs.
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