Simulation of dense non-aqueous phase liquid remediation through steam-enhanced extraction

Steam-enhanced extraction has been reviewed by many researchers as an innovative technology to remediate dense non-aqueous phase liquid (DNAPL) from subsurface. However, the application of steam-enhanced extraction to heterogeneous subsurface conditions is still obscurity and its implementation is limited due to steam flow sensitivity to site characterization. Two-dimensional (2-D) simulations were performed to assess the efficiency of steam-enhanced extraction in remediation of heterogeneous subsurface contaminated with tetrachloroethylene (PCE) spill. The simulation was performed with four different steam injection rates. The results shows that increased in steam injection rate will increase the PCE remediation time. The steam injection with the rate of 1.0 x 10-4 kg/s was successfully removing 100% of the PCE. There are significant impacts in the difference in remediation time with the increment approximately 20 min, 40 min and 70 min for every 2.0 x 10-5 kg/s increment. The dominant mechanisms of PCE removal is physical displacement through vaporization and co-boiling enhanced by steam distillation and steam stripping. The simulation results of steam-enhanced extraction for PCE removal was compared with surfactant-enhanced method implemented in existing experimental study. It was discovered that the time required to remove PCE using steam-enhanced extraction is four times faster than the time required to remove PCE using surfactant-enhanced method. This shows the capability of steam-enhanced extraction to recover contaminant more effectively. Steam-enhanced extraction has a greatest potential to decrease clean-up time which will offset greater capitol cost of the system

Antibiotics in the environment: mini review

Knowledge of pharmaceuticals in the environment is merely minute. Pharmaceuticals can enter the aquatic environment through the sewage treatment systems when they are excreted by people, or if they are disposed in the home. They can also enter sewage treatment works or waterways as a result of discharges from pharmaceutical manufacturing plants or medical establishments. The emission routes of veterinary drugs and feed additives to surface water are more complex than those of human pharmaceuticals. Emission to the surface water can take place either directly, when the animals are kept on pasture or indirectly by run-off and leaching through the soil. From an environmental side, the major effect of antibiotics is the toxic effect that may be exerted on aquatic organisms and disruption of the ecological balance. In addition, the presence of antibiotics in natural systems leads to the development of multi-resistant strains of bacteria. This paper outlines the different anticipated exposure routes to the environment, present knowledge of occurrence, fate and effect of pharmaceuticals

Safety analysis of ammonia exposure at a chemical plant

The Environmental Protection Agency (EPA) is issuing this Alert as part of its ongoing effort to protect human health and the environment by preventing chemical accidents. In chemical manufacturing industry, there are many hazards in the workplace particularly chemical hazard. Although there is safe work procedure for activities involving chemical handling, however, incidents of ammonia exposure are still occuring. Therefore, assessment on the workplace conditions and the knowledge and attitude of employees is essential to evaluate the extent of the problem. Accordingly, the objectives of this study are to (1) identify potential exposures, possible effects and root causes of ammonia exposure to workers, (2) to analyse knowledge and attitude of workers on ammonia exposure, and (3) to propose recommendations (guideline) for the improvement of safety handling of ammonia. A Job Safety Analysis was conducted to identify potential exposures, possible effects and root causes of ammonia exposure to workers. Knowledge and attitude questionnaire was conducted for 36 production workers of a company to analyse their knowledge and attitude on ammonia exposure. The results show that the potential ammonia exposures were from this areas; improper carboy cap fastening and lid absence, transfer spillage, residuals splashes, overcharging and continuous pumping, hose leakage, loose and dismantled, rushed scooping, manhole exposure, and charge-in pump not halted. The possible effects of ammonia exposures are carboy leaked, overspill, hose leaked, forced out through loosened hose, ammonia evaporated to fumes, ammonia fumes inhaled into respiratory system, sprinkles and splashes, and direct contact with skin and eyes. The root causes of ammonia exposures are; no initial checking, not wearing PPE, improper pouring method, mixing tank unattended, procedure overlooked, rushing, not following proper procedure, and pump control unattended. The workers’ knowledge of ammonia exposure was high, whereas their attitude was moderate. A guideline was proposed to improve safety handling of ammonia and enhance the knowledge and attitude of workers

Treatment of Textile Wastewater Using a Novel Electrocoagulation Reactor Design

This study explored the best operating conditions for a novel electrocoagulation (EC) reactor with the rotating anode for textile wastewater treatment. The influence of operating parameters like interelectrode distance (IED), current density (CD), temperature, pH, operating time (RT) and rotation speed on the removal efficiency of the contaminant was studied. A comparative study was done using conventional model with static electrodes in two phases under same textile wastewater. The findings revealed that the optimal conditions for textile wastewater treatment were attained at RT = 10 min, CD = 4 mA/cm2, rotation speed = 150 rpm, temperature = 25°C, IED = 1 cm and pH = 4.57. The removal efficiencies of color, biological oxygen demand (BOD), turbidity, chemical oxygen demand (COD) and total suspended solid (TSS) were 98.50, 95.55, 96, 98 and 97.10%, respectively, within the first 10 min of the reaction. The results of the experiment reveal that the newly designed reactor incorporated with cathode rings and rotated anode impellers provide a superior treatment efficiency within a short reaction time. The novel EC reactor with a rotating anode significantly enhanced textile wastewater treatment compared to the conventional model. The values of adsorption and passivation resistance validated the pollutants removal rate

Bioenergy production and nutrients removal by green microalgae with cultivation from agro-wastewater palm oil mill effluent (POME) - A review

Environmental pollution specifically wastewater is gaining attention both in the developed and developing countries. Malaysia is considered as one of the major palm oil producers in the world. Therefore, it is important to develop an environmental friendly and economic method to treat palm oil mill effluent (POME). The wastewater can serve as an economical nutrient source or substrate that can support the cultivation of microalgae. This can be a great nutrient for algal cultivation at the same time as remediating effluent and generating biomass. Nowadays, many microalgae species are being investigated to determine their potential and effectiveness for phytoremediation application, especially high growth rate. However, using synthetic media for growing microalgae in a mass scale is costly. It is acknowledged that POME (as nutrients enriched media) assisted enhanced microalgae growth under certain condition can considerably reduce the presence of organic and inorganic compounds. In this review, the potential of wide range of the predominant microalgae species with main focus on green microalgae (high removal efficiency): Chlamydomonas sp and Chlorella sp were investigated. Moreover, we discussed about the history, methods and future prospects in nutrients removal by green microalgae comprehensively. This review discusses several potential strategies for tackling the environmental issue generated by agro-waste water POME with enhancement of biomass productivity which can be used as an alternative for energy production

Sanitary landfill is a solution in solid waste management or a silent threat to environment: Malaysian scenario

In Malaysia, the population is increasing at a rapid rate reaching 32.6 million in 2019. This hasresulted in a tremendous amount of solid wastes being generated which was estimated as about38,200 tons per day (1.12 kg/cap/day), in 2018 enough to fill the Twin Towers every seven days.82.5% of which is disposed of in landfills. If not managed properly landfills can cause detrimentaleffects to environment, humans and aquatic world. Most of the landfills in Malaysia are lagging withadequate facilities. This paper encompasses the sections of history of solid waste management inMalaysia from 1970 to present, followed by some alarming and dreadful cases of pollution due toill management of landfills and lastly some of the substantial measures to combat with the acuteproblem of solid waste focussing on the responsibilities of government, manufacturer and user.Whether it be creating awareness among people and implementing laws,3R strategy or thinkingbefore throwing all play vial role in solid waste management. Collective and consistent effort isessential to achieve Malaysia’s targeted recycling rate of 22% by 2020 and hence achievingMalaysian vision with greater advancement towards a zero-waste nation

Performance of an up-flow anaerobic sludge bed (UASB) reactor treating landfill leachate containing heavy metals and formaldehyde

Municipal Solid Waste (MSW) landfill leachate is a serious environmental issue and treated using various methods, mostly involving biological treatment. In the present study, an up-flow anaerobic sludge bed (UASB) was used for the treatment of matured landfill leachate that contains heavy metals (As, Fe, Ni, and Cd) and Formaldehyde (FA). Accordingly, the OLR to the UASB reactor was gradually increased from 0.125 to 2.5 kg CODm-3d-1, to observe the process performance. The process performance of the reactor was characterized in terms of pH, Chemical Oxygen Demand (COD) removal, Total Volatile Acid (TVA) production, Mixed Liquor Suspended Solids (MLSS), Mixed Liquor Volatile Suspended Solids (MLVSS) washout, and Methane composition. Results showed that at a Hydraulic Retention Time (HRT) of 4 days and an OLR of 0.125 kg CODm-3d-1, up to 79.04% COD removal efficiency was observed. However, when the OLR was increased gradually from 0.375 to 2.5 kg CODm-3d-1, the COD removal efficiency decreased to 9.5%, suggesting that the high accumulation of heavy metals may have inhibited the methanogens. During this period, the heavy metal and formaldehyde concentration were 9.40, 0.43, 0.50, 12.80 and 8.60 mgL-1 respectively

Evaluation of awareness and safety among students and technicians in UTM research chemical laboratories

Incidences in chemical research laboratories have been occurring at an alarming rate resulting in chemical-related injuries and illnesses ranging from skin and eye irritation to burns, chronic diseases, or death. Students need to make safety as part of their daily routine when working in chemical research laboratories by understanding particular hazardous characteristics of chemicals they are using in order to prevent accidents. Standards such as OSHA’s Occupational Exposure to Hazardous Chemicals in Laboratory standard (29 CFR 1910.1450) can be used by institutions for safe work in research laboratories. The purpose of this study is to assess the awareness and safety of students and technicians in Universiti Teknologi Malaysia (UTM) chemical research laboratories, to identify the type of hazards in chemical research laboratories and propose improvements to existing guidelines. For this study, a qualitative method was used for data collection using a self-administered questionnaire for students and technicians and laboratory checklist. The data collected was analysed using Statistical Package for Social Sciences (SPPS). After various observations and analysis, it is recommended that chemical spillage and handling should be included in the existing guidelines for awareness and safety on hazards caused by chemical and acutement substances in the chemical research laboratories; students should be given safety practices training to create awareness and prevent laboratory accidents when carrying out experiments; and laboratory inspections should be carried out to see whether the students and technicians are adhering to laboratory rules and regulations

Drilling fluids: presence of hazardous BTEXs and crystalline silica

In the oil and gas industry occupational health risks due to drilling fluids is severe. Mixing room, shale shaker room and drill floor are sites where workers are highly exposed to air pollutants, hazardous dust and even substances generated via drilling fluids associated activities. Barite, calcium carbonate and linear paraffin or olef in-based oil are three types of chemical that are greatly used in huge quantities to prepare drilling fluids. These drilling fluids contain hazardous substances and pose health risks. Due to the occupational health risk, Occupational Safety and Health Administration OSHA Europe and USA have issued guidelines for the permissible exposure limit (PEL) to be at 5 mg/m3 for barium sulphate, 10 mg/m3 for calcium carbonate, 0.05 mg/m3 for crystalline silica and 0.05 mg/m3 for oil mists. Therefore, this study identified the presence of benzene, toluene, ethylbenzene and xylene (BTEX) ionic mists and crystalline silica in the drilling fluids. The grain size distribution of additives used in the drilling fluids was also determined. The results showed the presence of BTEX and crystalline silica based on random sampling. Therefore, the existing control measures are necessary to reduce the occupational health risks. As a control measure, Artificial Intelligence (AI) and Internet of Things (IoT) are necessary to be introduced for the automation of drilling fluids associated activities

Development of an operational excellence framework for organisational performance improvement in the Sudanese aviation industry

Purpose: This study aims to investigate the critical success factors (CSFs) for the successful implementation of operational excellence (OE) by the organisations in the Sudanese aviation industry. Besides that, this study intended to determine the resulted impacts in the improved organisational performance and competitive advantage and quantify the benefits. Design/methodology/approach: The CSFs of OE were provided and dissected to reveal their integrated components and importance levels. The factors include leadership, people management, continuous improvement, operational strategy, and asset optimisation. The impacts (outcomes) were further categorised into four categories, namely financial results, quality of products or services, efficiency, and satisfaction. The outcome groups were presented, while the weight of each outcome was highlighted. Findings: With the OE’s conceptual framework, the CSFs to achieve OE were identified. From the five main factors, the expert panel members suggested that the leadership factor was the most important factor to achieve OE in the Sudanese aviation industry. Ranking the five CSFs and 40 subfactors provided a better understanding of the Sudan situation, specifically the effective implementation of OE philosophy. Research limitations/implications: The findings of the subfactors reported in this study were not enough. As a result, future studies must focus on the detailed descriptions of subfactors related to each of the critical factors. Practical implications: The efficiency in the organisations is generated and enhanced when they become efficient in reducing time wastage, raw materials, and unnecessary processing, and energy used in transportation, storing, and operating plant. Besides, the state of effectiveness is achieved when the organisation achieves its long-term goals through increased customer satisfaction and proves its reason for being. OE is critical as it assures both the efficiency and effectiveness of organisations. Originality/value: Past research have relatively over-emphasised the unilateral “result-driven” perspective of OE that corresponds with the limited concern for enablers, critical forms, and focus of OE. Thus, this paper intended to address this issue