Emerging Promise of Therapeutic Approaches Targeting Mitochondria in Neurodegenerative Disorders

Mitochondria are critical for homeostasis and metabolism in all cellular eukaryotes. Brain mitochondria are the primary source of fuel that supports many brain functions, including intracellular energy supply, cellular calcium regulation, regulation of limited cellular oxidative capacity, and control of cell death. Much evidence suggests that mitochondria play a central role in neurodegenerative disorders (NDDs) such as Parkinson's disease, Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis. Ongoing studies of NDDs have revealed that mitochondrial pathology is mainly found in inherited or irregular NDDs and is thought to be associated with the pathophysiological cycle of these disorders. Typical mitochondrial disturbances in NDDs include increased free radical production, decreased ATP synthesis, alterations in mitochondrial permeability, and mitochondrial DNA damage. The main objective of this review is to highlight the basic mitochondrial problems that occur in NDDs and discuss the use mitochondrial drugs, especially mitochondrial antioxidants, mitochondrial permeability transition blockade, and mitochondrial gene therapy, for the treatment and control of NDDs.

The impact of mucormycosis (black fungus) on SARS-CoV-2-infected patients: at a glance

The emergence of various diseases during the COVID-19 pandemic made health workers more attentive, and one of the new pathogens is the black fungus (mucormycosis). As a result, millions of lives have already been lost. As a result of the mutation, the virus is constantly changing its traits, including the rate of disease transmission, virulence, pathogenesis, and clinical signs. A recent analysis revealed that some COVID-19 patients were also coinfected with a fungal disease called mucormycosis (black fungus). India has already categorized the COVID-19 patient black fungus outbreak as an epidemic. Only a few reports are observed in other countries. The immune system is weakened by COVID-19 medication, rendering it more prone to illnesses like black fungus (mucormycosis). COVID-19, which is caused by a B.1.617 strain of the SARS-CoV-2 virus, has been circulating in India since April 2021. Mucormycosis is a rare fungal infection induced by exposure to a fungus called mucormycete. The most typically implicated genera are Mucor rhyzuprhizopusdia and Cunninghamella. Mucormycosis is also known as zygomycosis. The main causes of infection are soil, dumping sites, ancient building walls, and other sources of infection (reservoir words "mucormycosis" and "zygomycosis" are occasionally interchanged). Zygomycota, on the other hand, has been identified as polyphyletic and is not currently included in fungal classification systems; also, zygomycosis includes Entomophthorales, but mucormycosis does not. This current review will be focused on the etiology and virulence factors of COVID-19/mucormycosis coinfections in COVID-19-associated mucormycosis patients, as well as their prevalence, diagnosis, and treatment.

In silico investigation and potential therapeutic approaches of natural products for COVID-19: Computer-aided drug design perspective

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a substantial number of deaths around the world, making it a serious and pressing public health hazard. Phytochemicals could thus provide a rich source of potent and safer anti-SARS-CoV-2 drugs. The absence of approved treatments or vaccinations continues to be an issue, forcing the creation of new medicines. Computer-aided drug design has helped to speed up the drug research and development process by decreasing costs and time. Natural compounds like terpenoids, alkaloids, polyphenols, and flavonoid derivatives have a perfect impact against viral replication and facilitate future studies in novel drug discovery. This would be more effective if collaboration took place between governments, researchers, clinicians, and traditional medicine practitioners’ safe and effective therapeutic research. Through a computational approach, this study aims to contribute to the development of effective treatment methods by examining the mechanisms relating to the binding and subsequent inhibition of SARS-CoV-2 ribonucleic acid (RNA)-dependent RNA polymerase (RdRp). The in silico method has also been employed to determine the most effective drug among the mentioned compound and their aquatic, nonaquatic, and pharmacokinetics’ data have been analyzed. The highest binding energy has been reported -11.4 kcal/mol against SARS-CoV-2 main protease (7MBG) in L05. Besides, all the ligands are non-carcinogenic, excluding L04, and have good water solubility and no AMES toxicity. The discovery of preclinical drug candidate molecules and the structural elucidation of pharmacological therapeutic targets have expedited both structure-based and ligand-based drug design. This review article will assist physicians and researchers in realizing the enormous potential of computer-aided drug design in the design and discovery of therapeutic molecules, and hence in the treatment of deadly diseases.

Challenges of rural women entrepreneurs in Bangladesh to survive their family entrepreneurship: a narrative inquiry through storytelling

Purpose

Family entrepreneurship benefits women because of their economic, family, and social needs. But, as rural women, it is not much easy for them to maintain their family entrepreneurship successfully. Thus, this paper aims to explore the main challenges faced by rural women entrepreneurs in Bangladesh to survive their family entrepreneurship.

Design/methodology/approach

This study is qualitative in nature, based on narrative inquiry. The purposive sampling technique was used as a part of a non-probability sampling method to collect the data from rural women entrepreneurs from three districts (Khulna, Shatkhira, and Sylhet) in Bangladesh engaged in family entrepreneurship. No new information was found after collecting the data from seven (07) respondents; thus, they were chosen as the final sample size.

Findings

The findings show that rural women entrepreneurs faced primarily social and cultural, financial, and skill-related challenges, though they face other challenges to survive their family entrepreneurship. The attitude and perception of society toward women and their roles are at the root of social and cultural barriers. Researchers also found that financial challenges have a colossal impact on rural women and the other problem.

Practical implications

Although entrepreneurial activities are essential for socio-economic development in these developing countries, this research adds to the existing information by highlighting the main challenges that rural women face when they want to be business owners and entrepreneurs.

Originality/value

Research on rural women entrepreneurship in Bangladesh is limited and new. This study can provide an overview of the challenges faced by the rural women entrepreneurs and provide them with a blueprint for the development of women entrepreneurs in developing countries.

Emerging Promise of Computational Techniques in Anti-Cancer Research: At a Glance

Research on the immune system and cancer has led to the development of new medicines that enable the former to attack cancer cells. Drugs that specifically target and destroy cancer cells are on the horizon; there are also drugs that use specific signals to stop cancer cells multiplying. Machine learning algorithms can significantly support and increase the rate of research on complicated diseases to help find new remedies. One area of medical study that could greatly benefit from machine learning algorithms is the exploration of cancer genomes and the discovery of the best treatment protocols for different subtypes of the disease. However, developing a new drug is time-consuming, complicated, dangerous, and costly. Traditional drug production can take up to 15 years, costing over USD 1 billion. Therefore, computer-aided drug design (CADD) has emerged as a powerful and promising technology to develop quicker, cheaper, and more efficient designs. Many new technologies and methods have been introduced to enhance drug development productivity and analytical methodologies, and they have become a crucial part of many drug discovery programs; many scanning programs, for example, use ligand screening and structural virtual screening techniques from hit detection to optimization. In this review, we examined various types of computational methods focusing on anticancer drugs. Machine-based learning in basic and translational cancer research that could reach new levels of personalized medicine marked by speedy and advanced data analysis is still beyond reach. Ending cancer as we know it means ensuring that every patient has access to safe and effective therapies. Recent developments in computational drug discovery technologies have had a large and remarkable impact on the design of anticancer drugs and have also yielded useful insights into the field of cancer therapy. With an emphasis on anticancer medications, we covered the various components of computer-aided drug development in this paper. Transcriptomics, toxicogenomics, functional genomics, and biological networks are only a few examples of the bioinformatics techniques used to forecast anticancer medications and treatment combinations based on multi-omics data. We believe that a general review of the databases that are now available and the computational techniques used today will be beneficial for the creation of new cancer treatment approaches.

Psychological status of mass people in the capital city of Bangladesh during COVID-19: Do home quarantine challenges matter?

This study aimed to identify the impact of home quarantine challenges on the psychological status of mass people during Coronavirus Disease (COVID-19) in the capital city (Dhaka) of Bangladesh. A highly organized questionnaire was created in "Google Form" and given to respondents at random via multiple social media sites, including WhatsApp, LinkedIn, and Messenger. However, a sample size of 208 people was taken and analysis was carried out using Statistical Package for the Social Sciences and Analysis of a Moment Structures software. Analysis showed that home quarantine challenges are positively related to the psychological status and home quarantine challenges have a significant impact on psychological status during COVID-19. In Bangladesh, the major challenges to home quarantine are lack of consciousness, lack of medical support, and the possibility of losing their current jobs. This study provides insight into the challenges of home quarantine and the psychological status of Bangladeshi people. The findings may be helpful for policymakers in identifying necessary measures to overcome these challenges. Only Dhaka division was taken out of seven divisions in Bangladesh to conduct this study, which might be difficult to generalize the findings of this study. Thus, in the future, it is suggested that more respondents from other divisions need to be covered.

The Gut Microbiota (Microbiome) in Cardiovascular Disease and Its Therapeutic Regulation

In the last two decades, considerable interest has been shown in understanding the development of the gut microbiota and its internal and external effects on the intestine, as well as the risk factors for cardiovascular diseases (CVDs) such as metabolic syndrome. The intestinal microbiota plays a pivotal role in human health and disease. Recent studies revealed that the gut microbiota can affect the host body. CVDs are a leading cause of morbidity and mortality, and patients favor death over chronic kidney disease. For the function of gut microbiota in the host, molecules have to penetrate the intestinal epithelium or the surface cells of the host. Gut microbiota can utilize trimethylamine, N-oxide, short-chain fatty acids, and primary and secondary bile acid pathways. By affecting these living cells, the gut microbiota can cause heart failure, atherosclerosis, hypertension, myocardial fibrosis, myocardial infarction, and coronary artery disease. Previous studies of the gut microbiota and its relation to stroke pathogenesis and its consequences can provide new therapeutic prospects. This review highlights the interplay between the microbiota and its metabolites and addresses related interventions for the treatment of CVDs.

Recent advancements of nanoparticles application in cancer and neurodegenerative disorders: At a glance

Nanoscale engineering is one of the innovative approaches to heal multitudes of ailments, such as varieties of malignancies, neurological problems, and infectious illnesses. Therapeutics for neurodegenerative diseases (NDs) may be modified in aspect because of their ability to stimulate physiological response while limiting negative consequences by interfacing and activating possible targets. Nanomaterials have been extensively studied and employed for cancerous therapeutic strategies since nanomaterials potentially play a significant role in medical transportation. When compared to conventional drug delivery, nanocarriers drug delivery offers various benefits, such as excellent reliability, bioactivity, improved penetration and retention impact, as well as precise targeting and administering. Upregulation of drug efflux transporters, dysfunctional apoptotic mechanisms, and a hypoxic atmosphere are all elements that lead to cancer treatment sensitivity in humans. It has been possible to target these pathways using nanoparticles and increase the effectiveness of multidrug resistance treatments. As innovative strategies of tumor chemoresistance are uncovered, nanomaterials are being developed to target specific pathways of tumor resilience. Scientists have recently begun investigating the function of nanoparticles in immunotherapy, a field that is becoming increasingly useful in the care of malignancies. Nanoscale therapeutics have been explored in this scientific literature and represent the most current approaches to neurodegenerative illnesses and cancer therapy. In addition, current findings and various biomedical nanomaterials' future promise for tissue regeneration, prospective medication design, and the synthesis of novel delivery approaches have been emphasized.

Natural therapeutics and nutraceuticals for lung diseases: Traditional significance, phytochemistry, and pharmacology

BACKGROUND

Lung diseases including chronic obstructive pulmonary disease (COPD), infections like influenza, acute respiratory distress syndrome (ARDS), asthma and pneumonia lung cancer (LC) are common causes of sickness and death worldwide due to their remoteness, cold and harsh climatic conditions, and inaccessible health care facilities.

PURPOSE

Many drugs have already been proposed for the treatment of lung diseases. Few of them are in clinical trials and have the potential to cure infectious diseases. Plant extracts or herbal products have been extensively used as Traditional Chinese Medicine (TCM) and Indian Ayurveda. Moreover, it has been involved in the inhibition of certain genes/protiens effects to promote regulation of signaling pathways. Natural remedies have been scientifically proven with remarkable bioactivities and are considered a cheap and safe source for lung disease.

METHODS

This comprehensive review highlighted the literature about traditional plants and their metabolites with their applications for the treatment of lung diseases through experimental models in humans. Natural drugs information and mode of mechanism have been studied through the literature retrieved by Google Scholar, ScienceDirect, SciFinder, Scopus and Medline PubMed resources against lung diseases.

RESULTS

In vitro, in vivo and computational studies have been explained for natural metabolites derived from plants (like flavonoids, alkaloids, and terpenoids) against different types of lung diseases. Probiotics have also been biologically active therapeutics against cancer, anti-inflammation, antiplatelet, antiviral, and antioxidants associated with lung diseases.

CONCLUSION

The results of the mentioned natural metabolites repurposed for different lung diseases especially for SARS-CoV-2 should be evaluated more by advance computational applications, experimental models in the biological system, also need to be validated by clinical trials so that we may be able to retrieve potential drugs for most challenging lung diseases especially SARS-CoV-2.

Role of Phenolic Compounds in Human Disease: Current Knowledge and Future Prospects

Inflammation is a natural protective mechanism that occurs when the body's tissue homeostatic mechanisms are disrupted by biotic, physical, or chemical agents. The immune response generates pro-inflammatory mediators, but excessive output, such as chronic inflammation, contributes to many persistent diseases. Some phenolic compounds work in tandem with nonsteroidal anti-inflammatory drugs (NSAIDs) to inhibit pro-inflammatory mediators' activity or gene expression, including cyclooxygenase (COX). Various phenolic compounds can also act on transcription factors, such as nuclear factor-κB (NF-κB) or nuclear factor-erythroid factor 2-related factor 2 (Nrf-2), to up-or downregulate elements within the antioxidant response pathways. Phenolic compounds can inhibit enzymes associated with the development of human diseases and have been used to treat various common human ailments, including hypertension, metabolic problems, incendiary infections, and neurodegenerative diseases. The inhibition of the angiotensin-converting enzyme (ACE) by phenolic compounds has been used to treat hypertension. The inhibition of carbohydrate hydrolyzing enzyme represents a type 2 diabetes mellitus therapy, and cholinesterase inhibition has been applied to treat Alzheimer's disease (AD). Phenolic compounds have also demonstrated anti-inflammatory properties to treat skin diseases, rheumatoid arthritis, and inflammatory bowel disease. Plant extracts and phenolic compounds exert protective effects against oxidative stress and inflammation caused by airborne particulate matter, in addition to a range of anti-inflammatory, anticancer, anti-aging, antibacterial, and antiviral activities. Dietary polyphenols have been used to prevent and treat allergy-related diseases. The chemical and biological contributions of phenolic compounds to cardiovascular disease have also been described. This review summarizes the recent progress delineating the multifunctional roles of phenolic compounds, including their anti-inflammatory properties and the molecular pathways through which they exert anti-inflammatory effects on metabolic disorders. This study also discusses current issues and potential prospects for the therapeutic application of phenolic compounds to various human diseases.

Natural Bioactive Molecules: An Alternative Approach to the Treatment and Control of COVID-19

Several coronaviruses (CoVs) have been associated with serious health hazards in recent decades, resulting in the deaths of thousands around the globe. The recent coronavirus pandemic has emphasized the importance of discovering novel and effective antiviral medicines as quickly as possible to prevent more loss of human lives. Positive-sense RNA viruses with group spikes protruding from their surfaces and an abnormally large RNA genome enclose CoVs. CoVs have already been related to a range of respiratory infectious diseases possibly fatal to humans, such as MERS, SARS, and the current COVID-19 outbreak. As a result, effective prevention, treatment, and medications against human coronavirus (HCoV) is urgently needed. In recent years, many natural substances have been discovered with a variety of biological significance, including antiviral properties. Throughout this work, we reviewed a wide range of natural substances that interrupt the life cycles for MERS and SARS, as well as their potential application in the treatment of COVID-19.

Thank you, COVID-19: Positive social psychology towards the new normal

During the time being, while everybody else is busy conversing about the adverse effects of COVID-19, researchers solemnly look forward to intensifying the positive effects of COVID-19 on political, economic, social, technological, environmental, and ethical (PESTEL) aspects, as it was unrevealed. The FGD (Focus Group Discussion) and Delphi methods were conducted from April 2020 to January 2021 through the online platform to collect the data. In this research, 40 graduates from 40 families were taken as our sample size who carried out the opinions of their family members. The average duration of the interview was 30-40 min. This article highlighted that COVID-19 has some positive effects on social-psychological aspects (PESTEL) and, people are trying to adapt to new practices (New Normal) to improve their lifestyles against the deadly virus. COVID-19 would pass, but life will never be the same; thus, researchers conduct the research based on a country, which may not be similar to the other cultures and countries' perceptions. This is the first and foremost study on the positive effects of covid-19 and a guideline to cope with any pandemic in the near future. The study's findings are intended to assist the community in developing positive social psychology to call the covid-19 into question and look forward to a new standard.

Investigation of Drug Distribution Process and Pharmacy Practices on Model Pharmacy in Dhaka City, Bangladesh

Objectives: In Bangladesh, Drug distribution process is very important cause of our increasing economic and development. In the recent days Model pharmacy has become an important theme of study for the student in pharmacy. In Bangladesh the introduction of the model pharmacy practice likes other skilled and semi-skilled health professionals will certainly improve primary health care system. The aim of the study was to develop a strategy to improve the overall services of model pharmacy in Bangladesh. Methodology: A total of 20 model pharmacies were the study subject. The study cover the model pharmacy located in Dhaka city, where each pharmacy was accounted through a questioner on random basis. The form includes their facilities, management system, drug distribution process and counseling system. Results: Study showed that, out of 20 Pharmacists, 95% of them used Software tools for their drug dispensing system. There was a helpline system for individual, online order within a short time of delivery system, discount system and membership card. The most important significant factors are counseling by “A grade” pharmacists, patient database system, affordable price and quality of medicine. Conclusions: If we improve those model pharmacies and if the aim is successful, then it will be spread across Bangladesh and model pharmacy will be established gradually with digitalization. Keyword: Model pharmacy, Bangladesh, Dhaka city, Pharmacist, Drug distribution process

A Study to find out the Correlation between Handgrip Strength and Hand Breadth of Bangladeshi Male Cricket Batsman

This cross sectional analytical type of study was conducted at department of Anatomy, Dhaka Medical College, Dhaka, Bangladesh from July 2015 to June 2016 on 50 adult Bangladeshi male sprinters (Group A) and 50 adult Bangladeshi male cricket batsman (Group B). Sample collection was done by convenient purposive sampling technique. History of any injury of hand during playing was excluded to construct standard measurement. Hand breadth was measured with the help of slide calipers. Hand grip strength Dynamometer was used to measure the hand grip strength. Paired Student's 't' test, unpaired student's 't' test and Pearson's correlation coefficient test were done for statistical analysis of the result. The aim of the present study was to determine hand breadth and average hand grip strength of Bangladeshi male cricket batsman to find out correlation between them that may be used as a baseline for other professions as well for future research in our country. The mean right and left hand grip strength was significantly higher in the cricket batsman than in the sprinters. The mean right and left hand breadth was found to be significantly higher in the cricket batsman than in the sprinters. Right and left hand grip strength showed significant positive correlation with hand breadth in both hand. The study findings suggest that regular physical exercise and training increase hand grip strength.

Antibacterial Effect of Aloe vera (Aloe barbadensis) leaf gel against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae

This experimental study was carried out to determine the antibacterial effect of Ethanolic extract of Aloe vera leaf gel (EAE) against standard strains of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae in the Department of Pharmacology & Therapeutics in collaboration with the Department of Microbiology, Mymensingh Medical College, Mymensingh, Bangladesh from July 2017 to June 2018. Ethanol extract was used in five different concentrations (100, 200, 300, 400 and 500μg/ml). Dose dependent inhibitory effect was seen against the test organisms using disc diffusion method. For S. aureus, Zones of inhibition (ZOI) were 7, 12, 13, 16 and 20 mm at 100, 200, 300, 400 and 500 μg/ml respectively; for P. aeruginosa, ZOI were 0, 7, 12, 14 and 17 mm at 100, 200, 300, 400 and 500 μg/ml respectively; for E. coli, ZOI were 0, 8, 12, 15 and 18 mm at 100, 200, 300, 400 and 500 μg/ml respectively; for K. pneumoniae, ZOI were 7, 10, 11, 13 and 17 mm at 100, 200, 300, 400 and 500 μg/ml respectively. The minimum inhibitory concentration (MIC) was assessed by broth dilution technique. The MICs of EAE for S. aureus, P. aeruginosa, E. coli and K. pneumoniae were 500, 650, 650 and 600 μg/ml respectively. From the study it is clearly observed that ethanolic extract of Aloe vera leaf gel possesses antibacterial effect against the test pathogens. Further studies are required to detect and isolate the biologically active ingredients present in the Aloe vera leaves which are responsible for this antibacterial effect. Hopefully, that would lead to the discovery of new and more potent antimicrobial agents originated from Aloe vera.

Seasonal Variations in Water Quality of the Ganges and Brahmaputra River, Bangladesh

Jahangirnagar University Environmental Bulletin, Vol.2, 71-82, 2013 DOI: http://dx.doi.org/10.3329/jueb.v2i0.16332

A power law approach to orifice flow rate calibration

Although standards for orifice flow meter design, installation, and calibration are supported herein, noncompliant devices exist in many pilot-, lab-scale, and on-board applications. For these, a common calibration practice is to preserve the ideal square root relation and determine a device specific discharge coefficient value. This work provides theoretical and empirical analyses to support relaxing the square root relation between orifice pressure drop and flow rate for noncompliant devices. The resulting power law relation is shown to improve accuracy, precision, and rangeability. Whether a device specific square root or power law model is used, it requires off-line or in-line calibration data. As such, a power law calibration model may only be useful for on-board and small-scale applications.

Comparison between tramadol hydrochloride & nalbuphine hydrochloride in the treatment of per-operative shivering after spinal anaesthesia

Per-operative shivering following spinal anaesthesia is a common problem in the operation theatre. Adequate management of shivering during operation is one of the goals of anesthesiologists for the benefit of the patient. Because there are many unpleasant and harmful effects caused by shivering in many patients especially respiratory and cardiac disease patients. For this reason aggressive and optimal treatment of per-operative shivering is essential to reduce the morbidity of the patients. Our observations were that occurrence of shivering was more in younger patients than older patients, thin patients than obese patients, anxious patients than non-anxious patients and more frequent in patients who received vasoconstrictor drugs, administration of fluid at running rate just before or during operation, administration of cold local anaesthetic agents (by taking drug from the freeze) into subarachnoid space. And shivering was better managed by administration of nalbuphine HCl and surface skin warming (wrapping of the skin). There are many studies regarding the incidence, prevention & treatment of post-operative shivering but there is no study regarding the incidence & treatment of per-operative shivering by nalbuphine following spinal anaesthesia. This study was designed to compare the anti-shivering efficacy and side effects (Nausea, Vomiting, and Somnolence) of tramadol hydrochloride with that of nalbuphine hydrochloride in the treatment of per-operative shivering following spinal anaesthesia. This study was also done to observe the incidence of shivering during operation following spinal anesthesia.

Recovering nutrients from wastewater treatment plants through struvite crystallization: CFD modelling of the hydrodynamics of UBC MAP fluidized-bed crystallizer

This paper is an attempt to model the hydrodynamics of the UBC (University of British Columbia) MAP (magnesium ammonium phosphate) fluidized bed crystallizer. In this study, a numerical investigation of hydrodynamics of the UBC MAP crystallizer was performed, using commercial computational fluid dynamics (CFD) software, Fluent 6.3. One of the main findings of this modelling effort is the relative distribution of the different phases, in this case solids (struvite crystals) and liquid (water), within the reactor. This information is very important, in the sense that it helps fixing the size of the crystallizer, which can be a significant factor, affecting the total cost of the process. Another finding of this simulation is the volume fraction distribution of the different sizes of solid particles, which actually provides insight into the hydrodynamics of the reactor and will fill up the knowledge gap in developing an overall mechanistic model for the crystallizer.

Phosphorus recovery from anaerobic digester supernatant by struvite crystallization: model-based evaluation of a fluidized bed reactor

This paper is an attempt to model the UBC (University of British Columbia) MAP (Magnesium Ammonium Phosphate) fluidized bed crystallizer. A mathematical model is developed based on the assumption of perfect size classification of struvitre crystals in the reactor and considering the movement of liquid phase as a plug flow pattern. The model predicts variation of species concentration of struvite along the crystal bed height. The species concentrations at two extreme ends (inlet and outlet) are then used to evaluate the reactor performance. The model predictions provide a reasonable good fit with the experimental results for both PO4-P and NH4-N removals. Another important aspect of this model is its capability of predicting the crystals size and the bed voidage at different height of the reactor. Those predictions also match fairly well with the experimental observations. Therefore, this model can be used as a tool for performance evaluation of the reactor and can also be extended to optimize the struvite crystallization process in the UBC MAP reactor.

Effects of various process parameters on struvite precipitation kinetics and subsequent determination of rate constants

In this paper, struvite (MgNH(4)PO(4).6H(2)O) precipitation kinetics were studied with different operating conditions (varying supersaturation, pH, Mg:P ratio, degree of mixing and seeding conditions) and relevant rate constants were determined by fitting a slightly modified first-order kinetic model to the experimental data obtained. The rate of change of ortho-P concentration in the bulk solutions increases with increasing supersaturation ratio. The estimated rate constants are 2.034, 1.716 and 0.690 hr(-1) for the supersaturation ratio of 9.64, 4.83, and 2.44, respectively. Kinetic parameters were also evaluated for the Mg:P ratio between the ranges of 1.0 and 1.6, indicating higher phosphorus removal efficiency with increasing Mg:P ratio. The rate constants were found to be 0.942, 2.034 and 2.712 hr(-1) for Mg:P ratios of 1.0, 1.3 and 1.6, respectively. The experimental observations for kinetic study of struvite precipitation with different stirrer speeds clearly show that the mixing intensity used had little effect on the intrinsic rate constants. K values found to be 2.034 and 1.902 h(-1) for 100 and 70 rpm, respectively. Seeding, with 250-500 microm of seed crystals during the struvite precipitation kinetics test, was found to have very little effect on the ortho-P removal.

Exploring the determination of struvite solubility product from analytical results

The solubility of magnesium ammonium phosphate hexahydrate (struvite) was determined in different water and wastewater solutions, by using the analytical results of the solubility tests conducted in the Environmental Engineering Lab at the University of British Columbia. The various factors affecting the struvite solubility such as pH, ionic strength and the temperature of the solutions were also studied in this project. The struvite solubility product values were found to vary significantly from one solution to another and over the range of the experimental conditions as well. For instance, the solubility product (Ksp) determined at 20 degrees C for anaerobic digester supernatant from the Penticton, B.C. Advanced Wastewater Treatment Plant, was found to vary from 8.46 x 10(-15) (pKsp =14.07) to 1.3 x 10(-13) (pKsp =12.89), over a pH range 6.45 to 8.97; while in the case of distilled water, with the same struvite crystals and at the identical temperature, it was found to vary from 5.21 x 10(-15) (pKsp=14.28) to 2.12 x 10(-13) (pKsp =12.67) over a pH range of 7.01 to 9.62. These results explore the possible reasons for widely varying struvite solubility reported in the literature. A possible correlation was also developed to correlate struvite solubility product with varying temperature. Furthermore, an attempt was made to establish a correlation between conductivity and calculated ionic strength of the solutions. A significant gap, between the values predicted by the correlation developed in this study and those predicted by the existing correlation, was also observed.