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The treatment of palm oil mill effluent (POME) has always been the topic of research in Malaysia due to the high concentration of total suspended solid (TSS) and oil and grease (O&G) ranges from 28 846 to 30 920 mg/L and 5614 to 8812 mg/L, respectively. Additionally, the release of methane gas during the treatment of POME in all of the palm oil mills has been the major contributor to greenhouse gas (GHG) effect. The main aim of this work is to evaluate the performance of the pilot-plant integrated anaerobic–aerobic bioreactor (IAAB) for POME treatment at two different phases: (a) startup and (b) long-term performance evaluation from an organic loading rate (OLR) of 10.5 to 32.5 gCOD/(L·day). Startup of the pilot-plant IAAB was successfully accomplished in 24 days with overall removal efficiencies in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solid (TSS) of at least 90% at the OLR of 8.0 gCOD/(L·day). The pilot-plant IAAB achieved high BOD, COD, and TSS removal efficiencies of more than 99% for OLR up to 30.0 gCOD/(L·day) with methane yield ranges from 0.0406 LCH₄/gCODᵣₑₘₒᵥₑd to 0.1312 LCH₄/gCODᵣₑₘₒᵥₑd. The effluent quality remained stable with BOD of 16–107 mg/L with a high percent of compliance with the discharge limit of 100 mg/L. The coupling of the Grau second-order and Stover–Kincannon models (anaerobic system) with the Stover–Kincannon model (aerobic system) will completely define the pilot-plant IAAB system. This pilot-plant research will provide valuable data and experiences required to design and commission a full-scale IAAB.

Since the introduction of polymer banknotes, they have become a new tool for corneal foreign body (CFB) self-removal. Being easily available, lightweight, and sturdy, polymer papers have become a popular and innovative method to dislodge CFB. Although ophthalmology services are easily accessible in Malaysia, ignorance, lack of health awareness, and the desire to avoid medical costs are among the reasons why patients remove CFB themselves. The sequalae span from only a faint scar with relatively good vision to total blindness. Our case series highlights three cases of CFB self-removal using polymer banknotes and their sequalae. To echo what has been known previously, self-awareness and occupational hazard education remain the most important and effective way to prevent vision loss.

Palm oil mills generate a large amount of wastewater, known as palm oil mill effluent, during the production of crude palm oil. The high organic contents in palm oil mill effluent have an excellent potential for biogas utilisation. Besides, such effluent must be further treated before discharge or reused in milling processes. In this respect, an integrated biogas and wastewater treatment system should be developed. The aim of this paper is to synthesise and optimise an integrated biogas and wastewater treatment system via a process systems engineering tool that yields maximum economic performance. To illustrate the proposed approach, a typical palm oil mill case study in Malaysia is presented. The variation in palm oil mill effluent availability is considered to evaluate the changes in performance and ensuring the flexibility of the developed system. As shown in the results, implementation of integrated biogas and wastewater treatment system in a typical 60 t/h mill in Malaysia could export up to 1.9 MW electrical power on average. Alternatively, 110,800 GJ/year of compressed biomethane can be produced when feed-in to the national grid is not available. The implementation of integrated biogas and wastewater treatment system successfully reduces greenhouse gas emissions by 50,430 t CO2e/year as compared with the conventional open ponding system practiced in the industry. Lastly, feasibility studies and strategies to promote biogas utilisation in the industry are performed.

A carotid-cavernous fistula (CCF) is an arteriovenous fistula with an abnormal connection between the carotid artery and cavernous sinus that can be sight and life-threatening. The conjunctival injection is often the most prominent feature, and patients are commonly misdiagnosed for other ocular conditions leading to a delay in diagnosis and treatment. All three patients in this case series presented with persistent red eyes. They were all treated for conjunctivitis and only referred for further workup when other progressing ocular symptoms occurred. The diagnosis of CCF was confirmed with digital subtraction angiography and with successful endovascular embolization, their ocular symptoms resolved with preserved optic nerve function. A high index of suspicion in patients presenting with an atypical red eye is very crucial for timely diagnosis of CCF.

Endogenous Klebsiella pneumoniae panophthalmitis commonly affects those with compromised immunity. The occurrence of this infection in healthy individuals is rare. We describe the case of a healthy adult who presented with endogenous Klebsiella pneumoniae panophthalmitis from an asymptomatic liver abscess. A 64-year-old, previously healthy gentleman presented with rapidly progressive left eye periorbital swelling and blurring of vision. He had a low-grade fever three days prior to the development of ocular symptoms, but otherwise no other systemic complaints. Visual acuity was light perception in the left eye, and ocular motility was restricted in all directions of gaze. Ocular examination revealed proptosis, severe conjunctival chemosis, hazy cornea, and fibrin deposition in the anterior chamber. The posterior segment could not be visualized. Ultrasound of the hepatobiliary system revealed an abscess in the right lobe of his liver. His blood cultures grew Klebsiella pneumoniae. Despite being treated with high-dose intravenous antibiotics, his eye condition deteriorated. Evisceration was performed when he developed scleral melting and globe perforation. We highlight the importance of a high index of suspicion of endogenous Klebsiella panophthalmitis as it can be easily missed in healthy adults. Early diagnosis and prompt management are needed to prevent morbidity and mortality from this devastating infection.

Purpose To describe the epidemiology of open globe injuries and its prognostic factors from the perspectives of a tertiary care centre in northern Malaysia. Methods A retrospective study of open globe injuries in a period of three years between June 2017 and May 2020. Patients presenting with open globe injuries were identified and recruited from hospital census. Case records were retrieved and analysed after recruitment. Results A total of 114 patients with 118 open globe injuries were included in the study. Four patients had bilateral eye involvement. Men were found to have seven and a half times higher rate of ocular injuries than women. The predominant age group of ocular trauma presentation was in younger adults between the age of 21 and 30 years old. Work-related injuries account for almost half of the globe injuries (48.7%) followed by motor vehicle accident-related, domestic accident-related, and others. The significant factors related to the visual outcome are presenting visual acuity (VA), presence of relative afferent pupillary defect (RAPD) and vitreous loss. Conclusion The factors related to visual outcomes in this study may aid the clinician in determining the visual prognosis of ocular injuries. Young working males were the most susceptible group to sustain penetrating ocular injuries due to their job nature. Health education and safety at workplace are essential to reduce the occurrence of ocular injuries.

Background: A diagnosis of ankylosing spondylitis (AS) is challenging and often delayed despitebpatients being symptomatic. Low back pain is the most common initial symptom, appearing in the second and third decades of life. Acute anterior uveitis (AAU) occurs much later in the course of the disease, often when the destruction of the spine is already debilitating. Objective: Here, we report three cases of AS that were diagnosed after the patients developed AAU. Methods: A case series illustrated AAU leading to the diagnosis of AS years after the initial episode of low back pain. A comparison of the clinical presentation, diagnosis, and outcomes was also illustrated. Result: We report three cases of acute anterior uveitis (AAU)-associated AS diagnosed only after many visits to the primary health care provider with the complaint of chronic low back pain. All three patients had irreversible radiological changes upon diagnosis of AS. The AAU resolved with topical steroids, and one patient developed cataract. Conclusion: A high index of suspicion of AS in a young adult with chronic back pain before the development of AAU may prevent further functional loss and provide a better prognosis. Diagnosis of AS following AAU is not only associated with dependency but also may rob the vision of a young adult.

Purpose: To investigate the prevalence of fundus and macular optical coherence tomography (OCT) findings, and the spectrum of dengue-related fundus presentation in a Malaysian tertiary hospital. The associations between platelet count and haematocrit level with fundus and macular OCT findings were also investigated. Design: Cross-sectional study. Methods: The study was conducted at Hospital Raja Permaisuri Bainun, Ipoh, from June to August 2015. Patients who consented to participate underwent a comprehensive ocular examination. Examination included a best-corrected distance (6 m) and near visual acuities, standard black-on-white Amsler chart testing, pupillary light reflex, fundus examination, followed by dilated fundus photographs and OCT of the macula. Results: A total of 134 patients were included in the study. The prevalence of positive fundus finding and macular OCT finding was 35% (95% confidence interval [CI]: 27%, 43%) and 13% (95% CI: 8%, 19%), respectively; 62 eyes of 47 patients had positive fundus findings, whereas 30 eyes of 18 patients had positive macular OCT findings. Scotoma (p < 0.001), near vision disturbance (p = 0.04), and abnormal Amsler findings (p < 0.001) were significantly associated with presence of macular OCT findings compared to absence of macular OCT findings. In the total of 268 eyes, the two most common fundus findings were vessel tortuosity (53 [20%]) and yellow subretinal dot (28 [10%]). Out of 30 eyes, diffuse retinal thickening was the most frequent OCT finding (22 [73%]), followed by 4 (13%) with foveolitis, 3 (10%) with cystoid macular oedema and 1 (3%) with submacular fluid. Platelet count and haematocrit were not associated with abnormal fundus or macular OCT manifestation in patients suffering from dengue fever. Conclusion: Our study revealed that the prevalence of clinical fundus and macular OCT findings among dengue inpatients was higher when compared to other countries, especially during dengue outbreaks. Furthermore, the spectrum of fundus and macular OCT findings in our population can be varied.

Headache can be a primary or secondary disorder. The characteristics of headache and its associated features, especially the presence of red flag signs, are important in distinguishing secondary from primary causes. Hemicrania continua is a type of primary headache disorder characterized by a continuous unilateral headache with episodes of exacerbations and association with cranial autonomic symptoms, which include several ocular symptoms. The absolute response to indomethacin remains the hallmark of this disease. We would like to report a rare case of hemicrania continua with scintillating scotoma during exacerbations apart from the typical autonomic features of conjunctival injection, ptosis, eyelid edema, and lacrimation.

Anaerobic digestion has been widely employed in waste treatment for its ability to capture methane gas released as a product during the digestion. Certain wastes, however, cannot be easily digested due to their low nutrient level insufficient for anaerobic digestion, thus co-digestion is a viable option. Numerous studies have shown that using co-substrates in anaerobic digestion systems improve methane yields as positive synergisms are established in the digestion medium, and the supply of missing nutrients are introduced by the co-substrates. Nevertheless, large-scale implementation of co-digestion technology is limited by inherent process limitations and operational concerns. This review summarizes the results from numerous laboratory, pilot, and full-scale anaerobic co-digestion (ACD) studies of wastewater sludge with the co-substrates of organic fraction of municipal solid waste, food waste, crude glycerol, agricultural waste, and fat, oil and grease. The critical factors that influence the ACD operation are also discussed. The ultimate aim of this review is to identify the best potential co-substrate for wastewater sludge anaerobic co-digestion and provide a recommendation for future reference. By adding co-substrates, a gain ranging from 13 to 176% in the methane yield was accomplished compared to the mono-digestions.

This paper reports a techno-economic assessment for industrial scale bio-flocculant production with okra as biomass feedstock. The sludge dewatering ability of the bio-flocculant was evaluated prior to economic analysis. Several optimisation strategies were investigated in order to lower the bio-flocculant production cost. The results showed that continuous mode microwave extraction was more economically beneficial than conventional extraction in batch and continuous modes. Sensitivity analysis revealed that the production cost was significantly affected by annual production and extract yield, and moderately influenced by raw material price. The optimised scheme for bio-flocculant production was continuous mode microwave extraction at 90° C, a residence time of 10 minutes, a water loading of 3.5 w/w and production rate of 220 tonnes per year. The economic assessment showed that the gross margin was positive, return on investment was in the expected range of 20 to 30% and payback time was within 5 years.

Three main parameters of palm oil mill effluent (POME) i.e. biological oxygen demand (BOD), total suspended solids (TSS) and oil and grease (O&G), at high concentrations, have hindered efficient anaerobic digestion (AD) due to sludge flotation and scum formation. In this study, Moringa Oleifera extract was co-digested with POME to allow TSS and O&G to be coagulated and settled, and hence, an immobilisation media formed for better digestibility. Mono-digestion (POME, T1 and M. oleifera extract, T2, separately) served as control while co-digestion involved dosing 50 mL of M. oleifera extract (500 mg/L) into a fixed volume of POME (450 mL) at two feeding modes: daily, day 1 to day 30 (T3) and one-time, day 1 (T4). Treatments T1-T4 were conducted in an enclosed AD system for 30 days and the undesirable organic materials removal efficiencies i.e. BODremoval, TSSremoval and O&Gremoval were compared. POME co-digestion, T4, showed an improved 92% TSSremoval, 94% BODremoval and methane yield of 24.3 mL CH4/g COD removed. The results suggested that the nitrogen-fixing capabilities of anoxic microbial cells enhanced proliferation and growth encapsulated within the immobilisation media. Methanogen bacterial DNAs isolated from POME, granular sludge and anaerobically-treated POME were identified as Methanoculleus spp., Methanolinea spp. and Methanoculleus spp., respectively. Two-step complementary DNA (cDNA) and quantitative polymerase chain reaction (qPCR) confirmed the highest methanogen DNA concentration in T4. Therefore, the naturally occurring underutilised M. oleifera can be an organic coagulant for efficient POME co-digestion with an overall 69% and 59.5% higher methane yield and TSSremoval than mono-digestion.

Bilateral optic disc swelling with bilateral abducens nerve palsy as the first presenting signs of sporadic primary Burkitt's lymphoma (BL) is very rare. We report this in a young immunocompetent individual. Initial misdiagnosis of idiopathic intracranial hypertension was made due to normal brain imaging with elevated opening pressure on lumbar puncture. After 2 months, he developed neurological deficits and neck swellings. Biopsy of swelling revealed BL. He received chemotherapy but succumbed before the second cycle. Signs of raised intracranial pressure warrant meticulous investigation. Multiple high-volume taps of lumbar puncture are advised if clinical suspicion of neurolymphomatosis is high.

Central serous chorioretinopathy (CSCR) is a retinal condition characterized by fluid accumulation in the subretinal space, resulting in neurosensory detachment or pigment epithelial detachment. The risk factors associated with this condition include male gender, middle age, smoking, stress and use of corticosteroids. We report a case of CSCR in a 37-year-old policeman with hypertension and bronchial asthma. He presented with sudden onset of bilateral blurring of central vision for 1 day, worse over the left eye. There were no other significant eye complaints. He is an active smoker and has been on long-term corticosteroids for asthma. On examination, the visual acuity was 6/9 bilaterally. The anterior segment of both eyes was normal. Examination of the right fundus revealed a dome-shaped swelling inferior to the fovea, while the left fundus showed circular detachment of the neurosensory retina at the macula. He was diagnosed to have bilateral central serous chorioretinopathy. He was also counseled to stop smoking. The corticosteroids were continued due to the risk of precipitating an asthma attack if they were withheld. Upon his next review two months later, his condition remained stable. CSCR is usually a self-limited condition, with good visual outcome. A thorough medical, social and drug history should be obtained, and patients advised to modify their lifestyle to eliminate or reduce risk factors such as smoking, stress and corticosteroid use.

We report a case series of dengue maculopathy with different ocular manifestations, managements, visual outcomes and sequelae of patients. All three cases were diagnosed to have dengue fever. Patients presented with symptoms of central scotoma (case 1 and case 3) and blurring of vision (case 2) on Day 9 of dengue fever. Fundus examination showed intra retinal haemorrhages (case 1 and case 2) and macula thickening (case 3). Optical coherence tomography (OCT) revealed macular thickening with intra retinal fluid (case 1) and diffuse retinal thickening (case 3), while in case 2, it had irregular ellipsoid line in OCT. Fundus fluorescence angiography (FFA) revealed parafoveal vasculitis. After treatment with systemic steroids, one patient had good visual outcome (case 2), while two others had a persistent central scotoma due to macula atrophy (case 3). Although it is a self limiting disease, but the mode of treatment is variable. Treatment with corticosteroids may hasten recovery of vision and prevent permanent visual impairment.

Palm oil mill effluent has been extensively researched via three different technologies, namely chemical, physicochemical and biological treatment methods. Biological treatment by anaerobic and aerobic means is currently the most commonly used method for palm oil mill effluent. However, the greatest challenge posed by them is the inconsistent biological oxygen demand of 20 mg/L for the final treated effluent. Large amount of investment for additional polishing plant prior to the final discharge has been utilised intentionally to further reduce the biochemical oxygen demand values, but the problem remains unresolved. The performance of current palm oil mill effluent treatment system deployed by the industry was evaluated by comparing two different types of anaerobic treatments: open ponding and covered lagoon systems (with hydraulic and gas mixing). The covered lagoon with hydraulic mixing achieved the highest chemical oxygen demand, total suspended solids, total volatile solids and lignin removal efficiencies of >80% compared to other systems which showed

Oil and grease, carbohydrate, protein, and lignin are the main constituents of high strength wastewaters such as dairy wastewater, cheese whey wastewater, distillery wastewater, pulp and paper mill wastewater, and slaughterhouse wastewaters. These constituents have contributed to various operational problems faced by the high-rate anaerobic bioreactor (HRAB). During the hydrolysis stage of anaerobic digestion (AD), these constituents can be hydrolyzed. Since hydrolysis is known to be the rate-limiting step of AD, the overall AD can be enhanced by improving the hydrolysis stage. This can be done by introducing pretreatment that targets the degradation of these constituents. This review mainly focuses on the biological pretreatment on various high-strength wastewaters by using different types of enzymes namely lipase, amylase, protease, and ligninolytic enzymes which are responsible for catalyzing the degradation of oil and grease, carbohydrate, protein, and lignin respectively. This review provides a summary of enzymatic systems involved in enhancing the hydrolysis stage and consequently improve biogas production. The results show that the use of enzymes improves the biogas production in the range of 7 to 76%. Though these improvements are highly dependent on the operating conditions of pretreatment and the types of substrates. Therefore, the critical parameters that would affect the effectiveness of pretreatment are also discussed. This review paper will serve as a useful piece of information to those industries that face difficulties in treating their high-strength wastewaters for the appropriate process, equipment selection, and design of an anaerobic enzymatic system. However, more intensive studies on the optimum operating conditions of pretreatment in a larger-scale and synergistic effects between enzymes are necessary to make the enzymatic pretreatment economically feasible.

With the growing volume of palm oil production, palm oil mill effluent (POME) is an inevitable by-product that causes serious environmental hazards if discharged directly to the environment. This is mainly due to its high concentrations of chemical oxygen demand (COD) and biochemical oxygen demand (BOD). Note however that, with its high organic content, POME is a great source for biogas production. Therefore, POME pollution abatement coupled with biogas capture and utilisation are vital in order to promote sustainable development goal for the palm oil industry. Conventionally, POME is treated by employing open ponding system without capturing biogas released from the anaerobic process. This treatment system is inefficient, requires large footprint, long hydraulic retention time (HRT) and is unable to consistently comply with the proposed stringent BOD regulatory limit of 20 mg/L to be imposed by Department of Environment (DOE). Hence, the current POME treatment trend is gearing towards biogas capture technology and integrated POME treatment system with the ultimate aim of achieving zero discharge concept in the palm oil mill. This can be achieved by integrating several bioprocesses, with the aim to transform POME into value-added products. This chapter will discuss the current POME treatment and biogas capture technologies, as well as to identify issues and challenges faced by the palm oil miller which deters the development of biogas plants in the mill. Development of biogas from POME will no doubt contribute substantially in Malaysia’s renewable energy sector in the near future.

Yoga has recently been touted as a means to improve physical and mental well-being. However, no form of exercise is without its risks. A 32-year-old Chinese female with moderate myopia complained of right eye sudden onset of floaters and mild blurring of vision after the head-down posture. The visual acuity was 6/12 in the right eye and 6/9 in the left eye. A right eye fundus examination showed posterior vitreous detachment, with a small blood clot located at the inferior margin of the optic disc. The patient was diagnosed with right eye vitreous hemorrhage secondary to acute posterior vitreous detachment and was managed conservatively. Acute changes in posture, especially between an upright and a head-down position, may cause acute posterior vitreous detachment. As yoga practitioners may be required to assume this head-down position, myopic patients should be warned of the possible ocular complications of this exercise.

The production of natural biopolymers as flocculants for water treatment is highly desirable due to their inherent low toxicity and low environmental footprint. In this study, bio-flocculants were extracted from Hibiscus/Abelmoschus esculentus (okra) by using a water extraction method, and the extract yield and its performance in sludge dewatering were evaluated. Single factor experimental design was employed to obtain the optimum conditions for extraction temperature (25–90 °C), time (0.25–5 h), solvent loading (0.5–5 w/w) and agitation speed (0–225 rpm). Results showed that extraction yield was affected non-linearly by all experimental variables, whilst the sludge dewatering ability was only influenced by the temperature of the extraction process. The optimum extraction conditions were obtained at 70 °C, 2 h, solvent loading of 2.5 w/w and agitation at 200 rpm. Under the optimal conditions, the extract yield was 2.38%, which is comparable to the extraction of other polysaccharides (0.69–3.66%). The bio-flocculants displayed >98% removal of suspended solids and 68% water recovery during sludge dewatering, and were shown to be comparable with commercial polyacrylamide flocculants. This work shows that bio-flocculants could offer a feasible alternative to synthetic flocculants for water treatment and sludge dewatering applications, and can be extracted using only water as a solvent, minimising the environmental footprint of the extraction process.

Using a membrane reactor for reversible transesterification reaction involves reaction and product separation within a single unit. However, a pseudohomogeneous reaction and heterogeneous separation must be maintained for successful membrane reactor operation. Present research is aimed to develop an integrated model of chemical and phase equilibrium (CPE) and modified Maxwell–Stefan equation that describes the simultaneous CPE and mass transport phenomena of biodiesel production from crude palm oil (CPO) using a membrane reactor. In the first part of this work, a systematic approach describing simultaneous CPE of CPO transesterification in the membrane reactor was developed with the reconciliation of transesterification reaction and phase equilibrium that involves six-component. The results revealed that regressed apparent equilibrium constant, Keq value of 17.557 ±1.51% were higher than the literatures. This indicates that forward reaction of the reversible CPO transesterification is much favored in the membrane reactor than the conventional reactor. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1968–1980, 2015

The mechanistic modeling of biodiesel production process in membrane reactor with the consideration of chemical reaction, phase equilibrium, and ultrafiltration is important for the membrane reactor design. In part II of this work, the chemical and phase equilibrium (CPE) model for crude palm oil transesterification reaction in the membrane reactor developed in part I is extended to an integration of CPE with modified Maxwell–Stefan model, which considers multicomponent mass transport phenomena of concentration polarization and intramembrane. A good fit of simulated permeate fluxes and apparent solute rejection to the experimental data shows that the model has a good prediction capability. Reversible fouling was found to be the major fouling and no pore plugging was observed. Simulation results verified that micelles were retained by the membrane at CPO:MEOH molar ratio of 1:24 and catalyst concentration of 0.5 wt %. However, phase inversion happened when catalyst concentration of 0.05 and 0.1 wt % were used. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1981–1996, 2015

Flocculation is an essential phenomenon in industrial wastewater treatment. Inorganic coagulants (salts of multivalent metals) are being commonly used due to its low cost and ease of use. However, their application is constrained with low flocculating efficiency and the presence of residue metal concentration in the treated water. Organic polymeric flocculants are widely used nowadays due to its remarkable ability to flocculate efficiently with low dosage. However, its application is associated with lack of biodegradability and dispersion of monomers residue in water that may represent a health hazard. Therefore, biopolymers based flocculants have been attracting wide interest of researchers because they have the advantages of biodegradability and environmental friendly. But, natural flocculants are needed in large dosage due to its moderate flocculating efficiency and shorter shelf life. Thus, in order to combine the best properties of both, synthetic polymers are grafted onto the backbone of natural polymers to obtain tailor-made grafted flocculants. This paper gives an overview of the development of different types of flocculants that were being investigated for treatment of industrial wastewater. Furthermore, their flocculation performance will be reviewed and the flocculation mechanism will be discussed.

Upflow anaerobic sludge blanket-hollow centered packed bed (UASB-HCPB) reactor was developed with the aim to minimize operational problems in the anaerobic treatment of Palm Oil Mill Effluent (POME) under thermophilic conditions. The performance of UASB-HCPB reactor on POME treatment was investigated at 55 °C. Subsequent to start-up, the performance of the UASB-HCPB reactor was evaluated in terms of i) effect of hydraulic retention time (HRT); ii) effect of organic loading rate (OLR); and iii) effect of mixed liquor volatile suspended solid (MLVSS) concentration on thermophilic POME treatment. Start-up up of the UASB-HCPB reactor was completed in 36 days, removing 88% COD and 90% BOD respectively at an OLR of 28.12 g L−1 d−1, producing biogas with 52% of methane. Results from the performance study of the UASB-HCPB reactor on thermophilic POME treatment indicated that HRT of 2 days, OLR of 27.65 g L−1 d−1 and MLVSS concentration of 14.7 g L−1 was required to remove 90% of COD and BOD, 80% of suspended solid and at the same time produce 60% of methane.

Optimization of an integrated anaerobic-aerobic bioreactor (IAAB) treatment system for the reduction of organic matter (Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD) and Total Suspended Solids (TSS) concentrations) in Palm Oil Mill Effluent (POME) to legal standards with high methane yield was performed for the first time under thermophilic condition (50°C–55°C) by using response surface methodology (RSM). The experiments were conducted based on a central composite rotatable design (CCRD) with three independent operating variables, organic loading rates in anaerobic compartment (OLRan) and mixed liquor volatile suspended solids (MLVSS) concentration in anaerobic (MLVSSan) and aerobic compartments (MLVSSa). The optimum conditions for the POME treatment were determined as OLRan of 15.6 g COD·L−1·d−1, MLVSSan of 43100 mg·L−1, and MLVSSa of 18600 mg·L−1, where high aerobic COD, BOD and TSS removal efficiencies of 96.3%, 97.9%, and 98.5% were achieved with treated BOD of 56 mg·L−1 and TSS of 28 mg·L−1 meeting the discharge standard. This optimization study successfully achieved a reduction of 42% in the BOD concentrations of the final treated effluent at a 48% higher OLRan as compared to the previous works. Besides, thermophilic IAAB system scores better feasibility and higher effectiveness as compared to the optimized mesophilic system. This is due to its higher ability to handle high OLR with higher overall treatment efficiencies (more than 99.6%), methane yield (0.31 L CH4·g−1 CODremoved) and purity of methane (67.5%). Hence, these advantages ascertain the applicability of thermophilic IAAB in the POME treatment or even in other high-strength wastewaters treatment.

Palm Oil Mill Effluent (POME) treatment has always been a topic of research in Malaysia. This effluent that is extremely rich in organic content needs to be properly treated to minimize environmental hazards before it is released into watercourses. The main aim of this work is to evaluate the potential of applying natural, chemically and thermally modified banana peel as sorbent for the treatment of biologically treated POME. Characteristics of these sorbents were analyzed with BET surface area and SEM. Batch adsorption studies were carried out to remove color, total suspended solids (TSS), chemical oxygen demand (COD), tannin and lignin, and biological oxygen demand (BOD) onto natural banana peel (NBP), methylated banana peel (MBP), and banana peel activated carbon (BPAC) respectively. The variables of pH, adsorbent dosage, and contact time were investigated in this study. Maximum percentage removal of color, TSS, COD, BOD, and tannin and lignin (95.96%, 100%, 100%, 97.41%, and 76.74% respectively) on BPAC were obtained at optimized pH of 2, contact time of 30 h and adsorbent dosage of 30 g/100 ml. The isotherm data were well described by the Redlich-Peterson isotherm model with correlation coefficient of more than 0.99. Kinetic of adsorption was examined by Langergren pseudo first order, pseudo second order, and second order. The pseudo second order was identified to be the governing mechanism with high correlation coefficient of more than 0.99.

Boron removal from synthetic wastewater by using palm oil mill boiler (POMB) ash impregnated with various chemical compounds (citric acid, tartaric acid, salicylic acid, barium chloride, calcium chloride anhydrous, and calcium chloride dihydrate) was being investigated in this study. The characteristics of POMB ash were analyzed based on ash content, carbon content, and BET surface area. The adsorption process was performed in a batch system with various parameters: dosage of POMB ash, residence time, shaking speed, temperature, and pH. The results show that impregnants increased the ability of POMB ash to adsorb boron, and the adsorption efficiency of boron was highly dependent on the pH. The optimization study shows that citric acid was the optimum impregnant on the POMB ash, with maximum boron removal efficiency of 65.69% at dosage of 6 g/50 mL at pH 7.0 with shaking speed of 100 rpm at 25 °C and 12 h of residence time.

The Department of Chemical and Environmental Engineering, The University of Nottingham, Malaysia Campus has introduced “Year 1 Assessment Week” to replace the conventional coursework assessment method. During the assessment week, the first year students are required to conduct activities in groups. The activities involve elements of experiment, analysis, interpretation and presentation. This paper evaluates and analyse the impacts of such assessment system in promoting transferable skills among the students. Three stages of reflection (Teaching Activity, Reflecting and Interpreting) were conducted throughout the study. Questionnaires completed by the students, feedback from lecturers and self-observations are taken as the measurement of this study. Based on the results from the questionnaires, it is noted that most of the students agreed or strongly agreed with the transferable skills of “data sorting”, “manipulating and analysing”, “logical reasoning”, “communication”, “creativity and innovation”, “safety and teamwork” and “independent learning” were being applied during the assessment week. However, they were uncertain on how the transferable skills of “working within limited and conflicting data” and “information technology” could be applied in the activities during the assessment week. Most of the lecturers agreed that the students achieved the basic requirements of the assessment and fulfilled the learning outcomes. However, some lecturers found that the presentation and report writing skills were not highlighted during the assessment. In addition, some experienced lecturers reflected critically that the limited materials used in some of the activities had limited the creativity of the students.

Transesterification of oils/triglycerides (TGs) with alcohol in the presence of catalyst has been the most commonly used process to produce biodiesel. Major limiting factors of conventional biodiesel transesterification process are phase separation and product purification. Precise and correct knowledge of the phase equilibrium behaviour is crucial for future industrial biodiesel reaction, separation and purification processes. For this purpose, it is important to consider the phase equilibrium behaviour in order to thoroughly understand the entire transesterification system for biodiesel production, which consists of six components. This work is to discuss on the liquid–liquid equilibrium (LLE) data of six-component system which involves TG, palm biodiesel (FAME), methanol (MeOH), glycerine (GLY), diglyceride (DG) and monoglyceride (MG). The phase equilibrium data of this system were determined experimentally through transesterification of crude palm oil (CPO). The experimental LLE data have been transposed into a pseudo-ternary diagram as TG–DG–MG + MeOH–GLY + FAME for better visualisation and understanding of the six-component system. Results showed that the transesterification of TG to FAME has formed a two-phase system where CPO-rich phase and MeOH-rich phase co-existed during the reaction. Due to immiscibility of CPO and MeOH, as well as the miscibility of FAME and MeOH, the LLE data suggested that at specific reaction operating condition, the reacted product (FAME) could be continuously removed by separating the MeOH phase from the CPO phase. This favours the forward transesterification reaction and eventually enhances the reaction efficiency to produce an oil-free FAME.

This work presents the evaluation of biokinetic coefficients for a novel integrated anaerobic-aerobic bioreactor (IAAB) at different organic loading rates (OLRs) (10.5-22.5 g COD/L per day) treating palm oil mill effluent. The overall efficiencies of the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were more than 99% for OLR up to 19.5 g COD/L day with biogas production containing 48-64% of methane. The effluent quality remained stable (BOD 80 mg/L) and satisfied with the discharge limit. Stover-Kincannon model was the most appropriate model to estimate the performance of anaerobic compartment of IAAB, while Monod model was best suited for describing the aerobic compartment.BOD: biochemical oxygen demand; COD: chemical oxygen demand; DO: dissolved oxygen; GLSS: gas-liquid-solid separator; MLSS: mixed liquor suspended solid; MLVSS: mixed liquor volatile suspended solid; POME: palm oil mill effluent; RAS: returned activated sludge; SBR: sequencing batch reactor; SVI: sludge volume index; TA: total alkalinity; TN: total nitrogen; TS: total solids; TSS: total suspended solids; UASB: upflow anaerobic sludge blanket; UASFF: upflow anaerobic sludge blanket fixed film; VFA: volatile fatty acid; VSS: volatile suspended solids.

Biodiesel is commonly produced from lipid feedstock, animal fats and waste cooking oil by transesterification reaction. Considering the depletion of fossil fuel, biodiesel is gaining more attention as a renewable and environmental friendly fuel. The rapid growth of biodiesel industry thereafter has raised concerns to many existing commercial biodiesel enterprises. The major issues like feedstock flexibility, yield productivity and environmental impact are always the challenges to the continuous growth of conventional biodiesel processing technology. The processing of biodiesel is greatly hinged on the rich scientific background and technology development for better process advancement. The present paper reviews various concerns raised from the commercial biodiesel processing technology. It also addresses some innovative process intensification (PI) technologies, which likely bring appropriate technological improvement for biodiesel production.

Recently, membrane reactor technology was used to produce high-quality biodiesel because of its advantage of simultaneous transesterification and separation. As the transesterification reaction involves two immiscible phases of methanol (MeOH) and oil (TG), a thorough investigation on the membrane reactor for biodiesel production with the consideration of chemical phase equilibrium (CPE) via modeling analysis, was conducted in this study. A mathematical model was developed based on the modified Maxwell-Stefan model with the incorporation of CPE. The formation of TG rich micelles dispersed in the continuous phase of MeOH was the most important hypothesis in the model development. The preliminary experiment results show that the permeate compositions from the membrane reactor were closely related to CPE of the system, which was highly depending on the MeOH to TG molar ratio. TG free permeate can only be obtained if the continuous phase of MeOH was free from TG and the TG rich micelles were retained by the membrane. The model verification further confirmed the formation of micelles dispersed in the continuous MeOH phase within the feed side of the membrane reactor and the model was able to predict the performance of the membrane reactor for biodiesel production at an acceptable accuracy. © 2012 American Institute of Chemical Engineers AIChE J, 59: 258–271, 2013

Palm oil mill effluent (POME) with average chemical oxygen demand (COD) and biochemical oxygen demand (BOD) of 70,000 and 30,000 mg/L, respectively, can cause serious environmental hazards if discharged untreated. There are conventional palm oil mill effluent (POME) treatment systems that require large footprint, long HRT and fail to meet the Malaysian Department of Environment (DOE) discharge limit. Hence, the current research is aimed to design a novel integrated anaerobic–aerobic bioreactor (IAAB) for POME treatment in order to overcome these shortcomings of the conventional system. IAAB is a new bioreactor configuration which integrates anaerobic and aerobic digestion in one reactor. The overall removal efficiencies in steady state condition in terms of chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) were more than 99% at the organic loading rate (OLR) of 10.5 g COD/L day with methane yield of 0.24 L CH4/g COD removed. The effluent quality remained stable (BOD < 70 mg/L) and complied with the discharge limit (BOD < 100 mg/L). Overall, the IAAB system exhibited good stability and pH adjustment was unnecessary. The results show that the IAAB achieves higher performance in terms of organic removal efficiency and methane yield at higher OLR and shorter HRT as compared to the conventional system. Further evaluations of its long-term performance are proposed for the subsequent study.

This research is aimed at improving the thermophilic aerobic treatment system of anaerobically digested palm oil mill effluent (POME) through optimization of mixed liquor suspended solids (MLSS) at high concentration range for the first time besides other parameters of organic loading rate (OLR), dissolved oxygen (DO) concentrations and settling time. Chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) removal ratios were measured as indicators of the system performance. Experimental results clearly indicate that MLSS and OLR are the crucial parameters in thermophilic aerobic treatment. Optimal COD, BOD and TSS removals up to 86%, 87% and 89%, respectively, were achieved with MLSS concentration and OLR of 27,000 mg/L and 2.5 g COD/(L day), respectively. More significantly, high MLSS concentration range which is yet to be reported was successfully applied and this has resulted in superior performance as compared to other thermophilic treatment studies. No significant improvement of the treatment efficiency was attained with DO concentration exceeding 5 mg/L and settling time up to 24 h. Hence, operation at DO concentration of 2 mg/L and settling time of 2 h gives a good compromise between effluent quality and system operating costs.

Palm oil mill effluent (POME) is a wastewater generated from palm oil milling activities which requires effective treatment before discharge into watercourses due to its highly polluting properties. The characterization of wastewater is the essential step in the design of any wastewater treatment plant (WWTP) in the industry as conducting pilot-scale tests to obtain design and operating parameters is time-consuming and expensive. Characterization of POME had been conducted in various studies which only involve parameters that were listed as discharge standards by local environmental authorities and those that were significant to the results of the chosen treatment methods. Other important parameters that were seldom considered in the characterization of POME are as follows: total phosphorus (TP), total organic carbon (TOC), total Kjeldahl nitrogen (TKN), total volatile solids (TVS), volatile suspended solids (VSS), lignin and sulfate concentrations, and toxicity. These parameters are very important in det...

Anaerobic systems operated under thermophilic condition often encounter longer start-up period and operating problems pertaining to temperature shift when mesophilic seed sludge were utilized as thermophilic sludge. Bioaugmentation products for thermophilic conditions were not readily available in the market. Hence, a thermophilic mixed culture has been cultivated specifically for Palm Oil Mill Effluent (POME) treatment at thermophilic conditions using a batch Continuous Stirred Tank Reactor (CSTR) where POME was utilized as a substrate for the growth of microbes. The thermophilic mixed culture managed to reduce at least 90% of Chemical Oxygen Demand (COD) in POME with a hydraulic retention time (HRT) of 6 days with a MLSS concentration of 14,000 mg/L. The biogas produced from the batch CSTR contained at least 64% of methane. The kinetic parameters for batch thermophilic POME treatment were obtained by fitting the Chen and Hashimoto's model to the experimental data. The maximum substrate utilization rate for this system was found to be 0.476 day −1 , which was higher than the systems operated under mesophilic range, and dimensionless kinetic parameters k and Q were −1.365 and 0.0007 respectively. The mixed culture had a methanogenic population which consisted of Methanosaeta thermophila , Methanosarcina thermophila , Methanobacterium thermoautotrophicum , Methanobacterium thermoformicicum and Methanobacterium wolfei .

The production of highly polluting palm oil mill effluent (POME) has resulted in serious environmental hazards. While anaerobic digestion is widely accepted as an effective method for the treatment of POME, anaerobic treatment of POME alone has difficulty meeting discharge limits due to the high organic strength of POME. Hence, subsequent post-treatment following aerobic treatment is vital to meet the discharge limits. The objective of the present study is to investigate the aerobic treatment of anaerobically digested POME by using a sequencing batch reactor (SBR). The SBR performance was assessed by measuring Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD) and Total Suspended Solids (TSS) removal as well as Sludge Volume Index (SVI). The operating pH and dissolved oxygen concentrations were found to be 8.25-9.14 and 1.5-6.4 mg/L, respectively, throughout the experiment. The experimental results demonstrate that MLVSS, OLR and sludge loading rate (SLR) play a significant role in the organic removal efficiency of SBR systems and therefore, further investigation on these parameters was conducted to attain optimum SBR performance. Maximum COD (95-96%), BOD (97-98%) and TSS (98-99%) removal efficiencies were achieved at optimum OLR, SLR and MLVSS concentration ranges of 1.8-4.2 kg COD/m(3)day, 2.5-4.6 kg TSS/m(3)day and 22,000-25,000 mg/L, respectively. The effluent quality remained stable and complied with the discharge limit. At the same time, the sludge showed good settling properties with average SVI of 65. It is envisaged that the SBR process could complement the anaerobic treatment to produce final treated effluent which meets the discharge limit.

Non-arteritic anterior ischaemic optic neuropathy (NAION) may develop due to severe anaemia and hypotension which is seen in acute blood loss. The devastating visual loss is often irreversible. We report a case of NAION in a 20-year-old healthy woman, who presented on the third day of a heavy menstrual cycle with hypovolaemic shock. On day 2 of admission, she had sudden right eye blurring of vision at the superior field on awakening from sleep. Funduscopy revealed a pale and swollen right optic disc. There was a dense right superior altitudinal visual field defect. Her haemoglobin level was low (3.6 g/dL), but she refused blood transfusion due to her religious belief (Jehovah's Witness) and opted for conservative management. She later developed right optic atrophy with persistent visual field defect despite an improved haemoglobin level of 10.5 g/dL.

Aerobic treatment of wastewater under thermophilic conditions has received growing interest in recent years. Because of the high discharge temperature (75 to 85 °C) of palm oil mill effluent (POME), it would be more economical if POME were treated thermophilically, as then cooling facilities prior to biological treatment can be eliminated. In the present investigation, the feasibility of thermophilic aerobic biological treatment as a suitable post-treatment system for anaerobically treated POME was examined. Also, the effects of temperature on the treated effluent quality were investigated by using sequencing batch reactors (SBRs) under mesophilic (28 °C) and thermophilic (45, 50, and 55 °C) conditions. The average total COD (TCOD) removal efficiencies varied from 55 to 98% at organic loading rates (OLR) of 2.6 to 4.5 kg COD/m3·day, dissolved oxygen (DO) concentrations of 2.9−4.5 mg/L, and mixed-liquor suspended solids (MLSS) concentrations of 22500−24200 mg/L. The results show that the thermophilic aerob...

Boron is extensively used in the ceramic industry for enhancing mechanical strength of the tiles. The discharge of boron containing wastewater to the environment causes severe pollution problems. Boron is also dangerous for human consumption and causes organisms' reproductive impediments if the safe intake level is exceeded. Current methods to remove boron include ion-exchange, membrane filtration, precipitation–coagulation, biological and chemical treatment. These methods are costly to remove boron from the wastewater and hence infeasible for industrial wastewater treatment. In the present research, adsorption–flocculation mechanism is proposed for boron removal from ceramic wastewater by using Palm Oil Mill Boiler (POMB) bottom ash and long chain polymer or flocculant. Ceramic wastewater is turbid and milky in color which contains 15 mg/L of boron and 2000 mg/L of suspended solids. The optimum operating conditions for boron adsorption on POMB bottom ash and flocculation using polymer were investigated in the present research. Adsorption isotherm of boron on bottom ash was also investigated to evaluate the adsorption capacity. Adsorption isotherm modeling was conducted based on Langmuir and Freundlich isotherms. The results show that coarse POMB bottom ash with particle size larger than 2 mm is a suitable adsorbent where boron is removed up to 80% under the optimum conditions (pH = 8.0, dosage = 40 g bottom ash/300 ml wastewater, residence time = 1 h). The results also show that KP 1200 B cationic polymer is effective in flocculating the suspended solids while AP 120 C anionic polymer is effective in flocculating the bottom ash. The combined cationic and anionic polymers are able to clarify the ceramic wastewater under the optimum conditions (dosage of KP 1200 B cationic polymer = 100 mg/L, dosage of AP 120 C anionic polymer = 50 mg/L, mixing speed = 200 rpm). Under the optimum operating conditions, the boron and suspended solids concentration of the treated wastewater were reduced to 3 mg/L and 5 mg/L respectively, satisfying the discharge requirement by Malaysia Department of Environment (DOE). The modeling study shows that the adsorption isotherm of boron onto POMB bottom ash conformed to the Freundlich Isotherm. The proposed method is suitable for boron removal in ceramic wastewater especially in regions where POMB bottom ash is abundant.

Palm oil mill effluent (POME) is a highly polluting wastewater that pollutes the environment if discharged directly due to its high chemical oxygen demand (COD) and biochemical oxygen demand (BOD) concentration. Anaerobic digestion has been widely used for POME treatment with large emphasis placed on capturing the methane gas released as a product of this biodegradation treatment method. The anaerobic digestion method is recognized as a clean development mechanism (CDM) under the Kyoto protocol. Certified emission reduction (CER) can be obtained by using methane gas as a renewable energy. This review aims to discuss the various anaerobic treatments of POME and factors that influence the operation of anaerobic treatment. The POME treatment at both mesophilic and thermophilic temperature ranges are also analyzed.

The present study is intended for the first time to completely replace the inorganic coagulants with organic polymers in palm oil mill effluent (POME) pretreatment by using direct flocculation of single and dual polymer systems under applied shear. The efficiency of direct flocculation of POME was investigated by using the Population Balance Model (PBM) which considered the charge neutralization and bridging attraction under applied shear. The collision efficiency was calculated based on the Derjaguin Landau Verwey Overbeek (DLVO) theory which considered the effect of adsorbed polymer layers on van der Waals attraction and bridging attraction. This is the first attempt to correlate the floc size distribution from PBM to the indirect indicators of COD, suspended solids, oil and grease. The model predictions are in close agreement with the experimental results for both single and dual polymer systems. The interaction energy curves based on PBM shows that the flocculation using cationic polymer is by charge neutralization and bridging attraction whereas flocculation using anionic polymer is by only bridging attraction. At the optimum flocculation conditions, 99.66%, 55.79%, 99.74% and 80.78% of suspended solids, COD, oil and grease removal and water recovery are achieved, respectively. The direct flocculation process significantly reduced the treatment cost by a factor of 3.6 compared to the conventional coagulation–flocculation process.

The adsorption of pretreated palm oil mill effluent (POME) onto a granular activated carbon (GAC) fixed bed has been studied using the incorporation of ideal adsorbed solution theory (IAST) into the homogeneous surface diffusion model (HSDM). The pretreated POME is a complex solution of a ternary system containing three major organic solutes of carbohydrate constituents, protein, and ammoniacal nitrogen. The incorporation of IAST into HSDM allows multicomponent adsorption predictions using single-solute equilibrium isortherms. Batch adsorption and fixed-bed adsorption were conducted to obtain the experimental data for a multicomponent adsorption system using pretreated POME. The residence time in the bed was varied by manipulating the bed length and the feed flowrate. On the basis of the comparison of the experimental breakthrough curves with the simulation results, IAST gives a good prediction of multicomponent adsorption on GAC when it is incorporated into HSDM.

A mathematical model suitable for the multiple solutes system in continuous cross-flow ultrafiltration is developed. This model is based on mass balance analysis coupled with the filtration theory (osmotic pressure model, Kozeny–Carman equation), resistance-in-series model and gel polarization model. This model is characterized by the parameters R m , P m , K b , K bi and k i . These parameters are estimated by using the Levenberg–Marquardt method coupled with the Gauss–Newton algorithm based on the experimental data obtained from the treatment of pretreated palm oil mill effluent (POME) as a feed in the pilot plant scale ultrafiltration system. The pretreated POME is composed of a ternary system with the solutes of carbohydrate constituents, crude protein and ammoniacal nitrogen. The simulation results show a good agreement with the experimental data. The proposed model is suitable for predicting the performance of multiple solutes in an ultrafiltration process. The concentration of each solute present is correlated with the COD value of the permeate stream.