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The increasing amount of annual red mud generation is becoming a global concern because of the environmental problems caused by its high metal content, alkalinity, and salinity. To manage red mud deposits, various green technologies have been implemented, such as phytoremediation and bioremediation. Accordingly, this study aimed to assess the morphological features of indigenous microbes in bauxite residue disposal areas (BRDA) in Indonesia. Using Gram staining method and microscopic analysis, indigenous microbial species were characterised based on morphological features such as colony profile, colour, size, margin, elevation and cell shape. As many as 10 isolates of indigenous microbes were successfully identified. All isolated were Gram positive and mostly white. The shape of colonies varied from irregular, circular, and filamentous with flat elevation, whereas the cell shape was identified as rod-shape and round-shape. Based on the similarity of the morphological characteristics of these microbes, there are five suspected genus, i.e., Micrococcus, Microbacterium, Bacillus, Cylindrogloea, Eubacterium, and Staphylococcus.

Recently, a problem which often experienced by the Environmental Agency is to monitor the quality of industrial waste. The problem comes from manual monitoring of wastewater and the high cost of laboratory tests for each variable for the waste. This system is intended to develop a wastewater monitoring system considering the state of the environment and technology. This system uses 5 types of sensors to measure the quality of wastewater. The sensor will display measurement data both offline via liquid crystal display (LCD) and online via the website. For the pH sensor test, we obtained an error value approximately of 1.32% and accuracy of 98.68%. For the oxidation reduction potential (ORP) sensor test, we obtained an error value of 1.4% with 98.6% accuracy. We obtained an error value of 0.22% with 99.78% accuracy for the temperature sensor test. For the total dissolved solid (TDS) sensor test, we obtained an error value of 1.02% with 98.98% accuracy. The color sensor is validated using a spectrometer to measure the variation of color in remazol waste concentration. For the Client - Server communication test, the system has a delay of 2 seconds. One of the advantages of using a web server is the system has minimum network traffic. [ABSTRACT FROM AUTHOR]

Electrochemical process has been widely applied to eliminate recalcitrant contaminants (i.e., organic and nitrogenous compounds) in landfill leachate. This study aimed to evaluate the performance of a hybrid electro-oxidation-dialysis (EOD) system to minimize organic and nitrogenous compounds through a synergistic process of electrochemical oxidation (EO) and electrodialysis (ED) as well as the dissolved organic matter was characterized in terms of fluorescent component and molecular weight distribution. The EOD was carried out using boron-doped diamond (BDD) and Pt alternately. The results have shown that pH adjustment to acidic conditions is beneficial to EO. At optimal pH (pH 4), BDD-based EO is superior to removing COD and ${\rm NH}_4^ +$ NH 4 + up to around 56% and 64%, respectively. During EOD process, the lower current density at 20.83 mA cm−2 is preferred for the recovery of nitrogenous ions (i.e. ${\rm NH}_4^ +$ NH 4 + and ${\rm NO}_3^\ndash$ NO 3 – ), especially for BDD-EOD. In addition, the dominant humic acid-like (HAL) and soluble microbial products-like (SMPL) substances in the mature leachate are mostly degraded to smaller molecules from 105 Da to 103 Da in both EOD processes. Overall, BDD-EOD favours indirect oxidation and has a higher energy consumption efficiency than Pt-EOD induced by direct oxidation for simultaneous removal of organic and nitrogenous compounds. BDD-EOD requires a lower total operation cost of around $2.33/m3 compared to Pt-EOD. It is concluded that the hybrid BDD-EOD process is technically feasible as a powerful pre-treatment approach to mature landfill leachate for refractory organics degradation and nitrogenous nutrients recovery. [ABSTRACT FROM AUTHOR]

The article discusses a study related to the use of compost from municipal solid waste to remove chromium and mercury from water. It notes that hydrogen ion displacements by heavy metal have decreased the potential of hydrogen (pH). It mentions that permeability has been increased by the pelletizing of compost.

Conventional biological treatments used in most Indonesian landfill sites are mostly ineffective in treating stabilized landfill leachates to meet the standard regulation. Thus, a combination of biological and electrochemical process is offered to successfully treat leachates containing a high concentration of organic and nitrogenous compounds. In this study, a moving bed biofilm reactor (MBBR) was applied prior to electrochemical oxidation by using boron-doped diamond (BDD), Ti/IrO 2 , and Ti/Pt anodes with applied current of 350, 400 and 450 mA. The objectives were to investigate the effect of anode type and the applied current on the removal of organics as well as total nitrogen from the MBBR-treated leachate with electrochemical oxidation. The optimum removal of chemical oxygen demand (COD) observed on the Ti/Pt anode was 78% by applying 400 mA, with an estimated energy of 56.7 Wh g L -1 . In the case of Ti/IrO 2 and BDD anodes, the optimum removal of COD was 76 and 85% with an energy consumption of 58.9 and 36.9 Wh g L -1 , respectively, both achieved at 350 mA. Although all anodes showed less-satisfactory performances for total nitrogen reduction, around 46-95% removal of nitrogenous compounds was achieved by MBBR, with their partial conversion to nitrates.