Optimization of municipal solid waste management strategy in Iskandar Malaysia using general algebraic modelling systems

Municipal solid wastes (MSW) are the materials generated, collected and discarded of in municipal areas because of their no or less value to the generator. Thousands of tonnes of MSW are produced annually in Iskandar Malaysia (IM), and the rate continues to increase due to high population growth, high degrees of urbanization, and industrialization. This increase in the amount of MSW makes its effective management an issue of great concern because of the cost implications and the threat it poses to human health and the environment. Hence it is absolutely essential to search for a better strategy to manage it in an economically viable and environmentally friendly manner. Three mathematical optimization models using linear programmes were developed and implemented using relevant data of IM region. In view of that, this research developed and solved three mathematical models using general algebraic modelling system software as a tool. The research objectives are; (i) To develop a cost-effective strategy for MSW collection and transportation from points of generation to disposal/recovery for a typical IM region using linear programming minimizing cost. (ii) To develop a single period MSW utilization strategy for revenue generation from the recyclable components of MSW in IM using an optimization tool to maximize profit. (iii) To estimate the biogas to electricity generation potential of the organic components of the MSW in IM. The results show the optimal transportation cost of MYR 5.97 million per week. The MSW amount transported from municipals to landfills to achieve cost-effective outcome are Pasir Gudang to Tanjung Langsat (2452 metric tonnes), Kulai to Pekan Nenas and Seelong (512 and 1501 metric tonnes), Pontian to Pekan Nenas and Seelong (1739 and 2214 metric tonnes), Johor Bahru to Pekan Nenas, Seelong and Tanjung Langsat (1739, 7485 and 18 metric tonnes), Johor Bahru to Pekan Nenas, Seelong and Tanjung Langsat (1739, 6881 and 110 metric tonnes). The total trucks to each landfills sites are Seelong, 988, Pekan Nenas, 313 and Tanjung Langsat 141. The highest and lowest trips are from Johor Bahru to Seelong and Tanjung Langsat at 429 and 1 respectively. The results also show the minimized cost of sorting MSW into recyclable is MYR 572,000. The highest and lowest recycled components are organics and glass (46 and 19 metric tonnes) at sorting units 1 and 5 respectively. The minimized cost of electricity generated from MSW is MYR 143,000 per week. The decentralized model shows that the highest utilization of organic is at Kulai municipal (400 metric tonnes) and lowest at Pontian (50 metric tonnes). A cost saving from 2,157,777.40 before to 1,965,161.82 after minimization, which is 8.9% in reduction was achieved. The models are also viable for recycling and biogas generation

Optimization approach for greenhouse gas to green energy for a low carbon region of Iskandar Malaysia

Landfill gas (LFG) like any other greenhouse gases (GHG) is a threat to the environment; hence its mitigation through effective utilization is necessary. The objective of this study is to estimate the amount of LFG captured using IPCC methodology and then develop optimization model for the LFG utilization for green energy production for Iskandar Malaysia. Of the three MSW Scenarios considered, the most appropriate was Scenario MIX, giving projection of MSW to landfill ranging from 600,000 tons in 2010 to 711,000 tons in 2035 for Iskandar Malaysia. From this, a mean annual LFG capture of 21,672 tons was estimated. The Mixed Integer Programing model considered Scenario ST as the more appropriate of the two LFG Scenarios, favoring combined heat and power generation with steam turbines over other options. The optimal result yielded a mean annual electricity and steam generation of 20,588 MWh (2.3 MW) and 150 million MJ respectively. The mean electricity generation represents 0.16% and 0.02% of the maximum electricity demand for Iskandar Malaysia and Peninsular Malaysia respectively. Additionally, GHG emission reduction of 12,000 tons CO2 equivalent was achieved. The findings revealed the potentials in LFG capture from the case study in terms of green energy and GHG emission reduction for sustainable development

Modelling ultrasound waves bubble formation in ethanol/ethyl acetate azeotrope mixture

The separation of an azeotropic mixture such as ethanol/ethyl acetate in distillation process can be enhanced by ultrasound wave. The application of ultrasound wave creates bubble cavitation in the mixture and shifts the vapour-liquid equilibrium favouring the separation of the azeotropic mixture. This study investigates the formation of bubbles in the mixture through modelling and simulation. The results obtained show that bubble formation at low ultrasound frequency is favoured by the increase in intensity, which has a direct relation to sonic pressure. The optimal sonic pressure for bubble formation at equilibrium is 5 atm and conforms to the model for small bubble formation with radius of 0.14 /<m. Furthermore, the maximum possible number of bubbles at equilibrium in the ethanol/ethyl acetate azeotropic mixture of 1 L is 91 × 1015. The developed model can be used to determine the optimal sonic pressure, sound intensity, size of bubble, and possible number of bubbles formed at equilibrium

Determinants of stillbirth from two observational studies investigating deliveries in Kano, Nigeria

Background: Stillbirths are a poignant representation of global inequality. Nigeria is documented to have the second highest rate; yet, the reporting system is inadequate in most Nigerian healthcare facilities. The aim was to identify the determinants of stillbirth among deliveries in the Murtala Muhammad Specialist Hospital (MMSH), Kano, Nigeria. Methods: Two study designs were used: a case-control study (S1) and a prospective cohort study (S2). Both studies were carried out at the MMSH. For S1, stillbirths were retrospectively matched to a livebirth by time (target of 24 hours' time variation) to establish a case-control study with a 1:1 ratio. Eligibility into S2 included all mothers who were presented at the MMSH in labour regardless of birth outcome. Both were based on recruitment durations, not sample sizes (3 months and 2 months, respectively, 2017–2018). The demographic and clinical data were collected through paper-based questionnaires. Univariable logistic regression was used. Multivariable logistic regression was used to explore relationships between area type and other specific factors. Findings: Stillbirth incidence in S2 was 180/1,000 births. Stillbirth was associated with the following factors; no maternal education, previous stillbirth(s), prematurity, living in both semi-rural and rural settings, and having extended time periods between rupture of membranes and delivery. Findings of the multivariable analysis (S1 and S2) indicated that the odds of stillbirth, for those living in a rural area, were further exacerbated in those mothers who had no education, lived in a shack, or had any maternal disease. Interpretation: This research identifies the gravity of this situation in this area and highlights the need for action. Further understanding of some of the findings and exploration into associations are required to inform intervention development. Funding: This collaboration was partially supported by funding from Health and Care Research Wales

Neonatal sepsis and mortality in low-income and middle-income countries from a facility-based birth cohort: an international multisite prospective observational study

Background Neonatal sepsis is a primary cause of neonatal mortality and is an urgent global health concern, especially within low-income and middle-income countries (LMICs), where 99% of global neonatal mortality occurs. The aims of this study were to determine the incidence and associations with neonatal sepsis and all-cause mortality in facility-born neonates in LMICs. Methods The Burden of Antibiotic Resistance in Neonates from Developing Societies (BARNARDS) study recruited mothers and their neonates into a prospective observational cohort study across 12 clinical sites from Bangladesh, Ethiopia, India, Pakistan, Nigeria, Rwanda, and South Africa. Data for sepsis-associated factors in the four domains of health care, maternal, birth and neonatal, and living environment were collected for all mothers and neonates enrolled. Primary outcomes were clinically suspected sepsis, laboratory-confirmed sepsis, and all-cause mortality in neonates during the first 60 days of life. Incidence proportion of livebirths for clinically suspected sepsis and laboratory-confirmed sepsis and incidence rate per 1000 neonate-days for all-cause mortality were calculated. Modified Poisson regression was used to investigate factors associated with neonatal sepsis and parametric survival models for factors associated with all-cause mortality. Findings Between Nov 12, 2015 and Feb 1, 2018, 29 483 mothers and 30 557 neonates were enrolled. The incidence of clinically suspected sepsis was 166·0 (95% CI 97·69–234·24) per 1000 livebirths, laboratory-confirmed sepsis was 46·9 (19·04–74·79) per 1000 livebirths, and all-cause mortality was 0·83 (0·37–2·00) per 1000 neonate-days. Maternal hypertension, previous maternal hospitalisation within 12 months, average or higher monthly household income, ward size (>11 beds), ward type (neonatal), living in a rural environment, preterm birth, perinatal asphyxia, and multiple births were associated with an increased risk of clinically suspected sepsis, laboratory-confirmed sepsis, and all-cause mortality. The majority (881 [72·5%] of 1215) of laboratory-confirmed sepsis cases occurred within the first 3 days of life. Interpretation Findings from this study highlight the substantial proportion of neonates who develop neonatal sepsis, and the high mortality rates among neonates with sepsis in LMICs. More efficient and effective identification of neonatal sepsis is needed to target interventions to reduce its incidence and subsequent mortality in LMICs. Funding Bill & Melinda Gates Foundation

Effects of antibiotic resistance, drug target attainment, bacterial pathogenicity and virulence, and antibiotic access and affordability on outcomes in neonatal sepsis: an international microbiology and drug evaluation prospective substudy (BARNARDS)

Background Sepsis is a major contributor to neonatal mortality, particularly in low-income and middle-income countries (LMICs). WHO advocates ampicillin–gentamicin as first-line therapy for the management of neonatal sepsis. In the BARNARDS observational cohort study of neonatal sepsis and antimicrobial resistance in LMICs, common sepsis pathogens were characterised via whole genome sequencing (WGS) and antimicrobial resistance profiles. In this substudy of BARNARDS, we aimed to assess the use and efficacy of empirical antibiotic therapies commonly used in LMICs for neonatal sepsis. Methods In BARNARDS, consenting mother–neonates aged 0–60 days dyads were enrolled on delivery or neonatal presentation with suspected sepsis at 12 BARNARDS clinical sites in Bangladesh, Ethiopia, India, Pakistan, Nigeria, Rwanda, and South Africa. Stillborn babies were excluded from the study. Blood samples were collected from neonates presenting with clinical signs of sepsis, and WGS and minimum inhibitory concentrations for antibiotic treatment were determined for bacterial isolates from culture-confirmed sepsis. Neonatal outcome data were collected following enrolment until 60 days of life. Antibiotic usage and neonatal outcome data were assessed. Survival analyses were adjusted to take into account potential clinical confounding variables related to the birth and pathogen. Additionally, resistance profiles, pharmacokinetic–pharmacodynamic probability of target attainment, and frequency of resistance (ie, resistance defined by in-vitro growth of isolates when challenged by antibiotics) were assessed. Questionnaires on health structures and antibiotic costs evaluated accessibility and affordability. Findings Between Nov 12, 2015, and Feb 1, 2018, 36 285 neonates were enrolled into the main BARNARDS study, of whom 9874 had clinically diagnosed sepsis and 5749 had available antibiotic data. The four most commonly prescribed antibiotic combinations given to 4451 neonates (77·42%) of 5749 were ampicillin–gentamicin, ceftazidime–amikacin, piperacillin–tazobactam–amikacin, and amoxicillin clavulanate–amikacin. This dataset assessed 476 prescriptions for 442 neonates treated with one of these antibiotic combinations with WGS data (all BARNARDS countries were represented in this subset except India). Multiple pathogens were isolated, totalling 457 isolates. Reported mortality was lower for neonates treated with ceftazidime–amikacin than for neonates treated with ampicillin–gentamicin (hazard ratio [adjusted for clinical variables considered potential confounders to outcomes] 0·32, 95% CI 0·14–0·72; p=0·0060). Of 390 Gram-negative isolates, 379 (97·2%) were resistant to ampicillin and 274 (70·3%) were resistant to gentamicin. Susceptibility of Gram-negative isolates to at least one antibiotic in a treatment combination was noted in 111 (28·5%) to ampicillin–gentamicin; 286 (73·3%) to amoxicillin clavulanate–amikacin; 301 (77·2%) to ceftazidime–amikacin; and 312 (80·0%) to piperacillin–tazobactam–amikacin. A probability of target attainment of 80% or more was noted in 26 neonates (33·7% [SD 0·59]) of 78 with ampicillin–gentamicin; 15 (68·0% [3·84]) of 27 with amoxicillin clavulanate–amikacin; 93 (92·7% [0·24]) of 109 with ceftazidime–amikacin; and 70 (85·3% [0·47]) of 76 with piperacillin–tazobactam–amikacin. However, antibiotic and country effects could not be distinguished. Frequency of resistance was recorded most frequently with fosfomycin (in 78 isolates [68·4%] of 114), followed by colistin (55 isolates [57·3%] of 96), and gentamicin (62 isolates [53·0%] of 117). Sites in six of the seven countries (excluding South Africa) stated that the cost of antibiotics would influence treatment of neonatal sepsis

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

RESPONSE OF COWPEA (Vigna unguiculata L.) TO IRRIGATION WATER DEFICIT AT DIFFERENT GROWTH STAGES IN SEMI-ARID, NIGERIA

Field experiments were conducted during the 2007/2008 dry season farming in Maiduguri, Borno state; in the northern Sahel savanna agro-ecological zone of Nigeria to evaluate the effect of imposing a 50% irrigation water deficit at different stages of growth of cow pea (Vigna unguiculata L) on growth and yield of the crop. The experiment was laid out in a randomized complete block design with three replications using basin irrigation system. The results indicated that the reduction in 50% of irrigation water requirement had affected the both the growth and yield of the crop. It also showed that water savings are possible without significant effect on the growth and yield of the crop at stages 1, 2, 4 and 1&4. Applying the same water stress at two or more stages of growth of the crop has a detrimental consequence

Economic and environmental benefits of landfill gas from municipal solid waste in Malaysia

Discharge of Green House Gases (GHGs) and the management of municipal solid waste (MSW) continue to be a major challenge particularly in growing economies. However, these are resources which can be converted to green energy. Landfill gas which is essentially methane (50–55%) and carbon dioxide (40–45%) (both GHGs) is released from MSW by biodegradation processes. The estimation of this methane and its economic and environmental benefits for environmental sustainability are the objectives of this study. Methane emission from MSW disposed of in landfills was estimated using Intergovernmental Panel on Climate Change (IPCC) methodology. From the study, based on 8,196,000 tonnes MSW generated in Peninsular Malaysia in 2010, anthropogenic methane emission of about 310,220 tonnes per year was estimated. This was estimated to generate 1.9 billion kWh of electricity year−1 worth over RM 570 million (US$190 million). In addition, this leads to carbon dioxide reduction of 6,514,620 tonnes year−1 equivalent to carbon credit of over RM 257 million (US$85 million). These results were also projected for 2015 and 2020 and the outcomes are promising. Therefore, the exploration of this resource, besides the economic benefits helps in reducing the dependence on the depleting fossil fuel and hence broadening the fuel base of the country

Economic and environmental evaluation of landfill gas utilisation: A multi-period optimisation approach for low carbon regions

Landfill gas (LFG) is composed essentially of the most problematic greenhouse gases (GHGs) namely methane (50%) and carbon dioxide (45%). However, due to its methane content, LFG can be utilised as a renewable energy source, but utilising LFG is met with a lot of challenges such as choice for LFG grade (low, medium or high grade), LFG utilisation equipment (gas engines, gas turbines etc.) and product type (electricity, heat etc.). The study estimates LFG capture and develops tool for the utilisation of LFG as a renewable energy resource. The Intergovernmental Panel on Climate Change model outcome shows that an average annual LFG capture of 17,200 tonnes was obtained for Iskandar Malaysia and the optimal results indicate that the LFG is best utilised as a medium grade LFG for combined heat and power generation using steam turbines. The profitability evaluation shows that mean annual profit of US$5.6 million has been achieved with a payback period of 12.3 years and net present value of US$111 million, which is reasonable because the project can be classified as medium to large-scale. Additionally, the study provides insight into the viability of various LFG utilisation technologies and strategies for waste disposal to landfill