Optimization of Ammonia Removal from Landfill Leachate by Aeration Using Response Surface Methodology (RSM)

Landfill leachate has a high concentration of ammonia, making it a harmful pollutant for both surface and groundwater. One of the most favoured methods for removing ammonia from leachate is aeration, as it has been proven to remove a significant amount of ammonia in the most efficient and economical way. The effect of operational variables on ammonia removal efficiency by aeration was investigated in the current study by applying Response Surface Methodology (RSM) approach. Three operating parameters such as airflow rate, aeration time and lime dosage were investigated to achieve the optimization of ammonia removal. The optimal parameters for a favourable reaction of ammonia-nitrogen (NH3N) removal were found to be 6 L/min airflow, 90 minutes aeration time, and a lime dosage of 6 g/L. At these ideal conditions, Quadratic RSM predicted a maximum NH3N removal of 98.0%, which has been validated by the experiment and successfully removed 97.6%. The finding also showed that airflow rate and aeration time were more significant than lime dosage for NH3N removal. Due to increased contact time between air and liquid, regardless of the amount of lime used, increasing the aeration period ammonia removal efficiency. Considering the influential factors, determining the optimum condition for ammonia removal by aeration will explain the potential interferences that may inhibit the efficient recovery of NH3N. Hence, aeration is a promising approach for ammonia removal from landfill leachate

A review on the effects of flame retardant additives towards the environment and human health

Flame retardant additives (FRAs) are normally the addition of chemicals that function to prevent or slow the spread of fires. These chemicals are used in consumer products and industries and could retain in the environment even after several decades. The toxicity mechanism and risk assessment methods of FRAs are also discussed in this paper. Papers from Scopus, Elsevier, Environmental health perspectives (EHP), Research gate, Semantic scholar, Hindawi, and Pubmed from 2003 to recent years were reviewed to provide some views on the possible risks of FRAs and their pathways into our environment as well as into human body. While FRAs could enter the environment during the manufacturing process and the usage period, consumer items are treated with FRAs, through waste streams, during illegal open burning of solid wastes, from incineration plants from landfill leachate and wastewater treatment plant (WWTP) sludge. FRAs are hazardous to humans and the environment, therefore, toxicology assessment should also be consistently conducted on the latest FRAs to ensure that they would not have adverse effects on humans and the environment

Unravelling The Deposition of Indoor Microplastics at Various Heights Across Rooms

Microplastics (MP) are widely present in both outdoor and indoor environments. Extensive research has thoroughly documented the potential negative impacts of MPs on human health. This study utilized a deposited sample method for 3 weeks, with eight-hour daily exposures, using funnels and bottles to investigate the properties of MPs in the office and laboratory settings of the Faculty of Civil Engineering & Technology (FCET), Universiti Malaysia Perlis. The characteristics examined included the deposition rate, size, form, and colour of the microplastics. Samples were collected at three different heights. The samples underwent pre-treatment procedures, such as physical counting and categorization (size, colour and shape). Micro-Raman analysis was performed to determine the primary polymer types. The deposition rate in the office was found to be 4,960 counts/(m2.h), while the rate in the laboratory was 6,940 counts/(m2.h). Human activities and the appearance of synthetic materials, especially from textiles, play a big role in the deposition rate of MPs in the environment. During the day, the rates were higher than at night. The results of the study showed that indoor MPs come in many different colours, with transparent and black being the most common. About 42% of the size range of fibrous MPs was between 200 µm and 2000 µm, and more than 15% of the particles were between 20 µm and 200 µm. Most of the time, fragments were smaller than strands. The most abundance polymers detected in both rooms were polycarbonate (PC), pigments and polymethyl methacrylate (PMMA)

Optimization of Ammonia Removal from Landfill Leachate by Aeration Using Response Surface Methodology (RSM)

Landfill leachate has a high concentration of ammonia, making it a harmful pollutant for both surface and groundwater. One of the most favoured methods for removing ammonia from leachate is aeration, as it has been proven to remove a significant amount of ammonia in the most efficient and economical way. The effect of operational variables on ammonia removal efficiency by aeration was investigated in the current study by applying Response Surface Methodology (RSM) approach. Three operating parameters such as airflow rate, aeration time and lime dosage were investigated to achieve the optimization of ammonia removal. The optimal parameters for a favourable reaction of ammonia-nitrogen (NH3N) removal were found to be 6 L/min airflow, 90 minutes aeration time, and a lime dosage of 6 g/L. At these ideal conditions, Quadratic RSM predicted a maximum NH3N removal of 98.0%, which has been validated by the experiment and successfully removed 97.6%. The finding also showed that airflow rate and aeration time were more significant than lime dosage for NH3N removal. Due to increased contact time between air and liquid, regardless of the amount of lime used, increasing the aeration period ammonia removal efficiency. Considering the influential factors, determining the optimum condition for ammonia removal by aeration will explain the potential interferences that may inhibit the efficient recovery of NH3N. Hence, aeration is a promising approach for ammonia removal from landfill leachate