Kinetic Modeling and Mechanisms of Manganese Removal from Alkaline Mine Water Using a Pilot Scale Column Reactor

Manganese (Mn) is a major element in various aqueous and soil environments that is sometimes highly concentrated in mine water and other mineral processing wastewater. In this study, we investigated Mn removal from alkaline mine water (pH > 9) with an Mn-coated silica sand packed into a pilot-scale column reactor and examined the specific reaction mechanism using X-ray absorption near-edge structure (XANES) analysis and geochemical kinetic modeling. The kinetic effect of dissolved Mn(II) removal by birnessite (δ-Mn(IV)O2) at pH 6 and 8 was evaluated at different Mn(II)/Mn(IV) molar ratios of 0.1–10. Our results confirmed the positive effect of the presence of δ-MnO2 on the short-term removal (60 min) of dissolved Mn. XANES analysis results revealed that δ-MnO2 was more abundant than Mn(III)OOH in the reactor, which may have accumulated during a long-term reaction (4 months) after the reactor was turned on. A gradual decrease in dissolved Mn(II) concentration with depth was observed in the reactor, and comparison with the kinetic modeling result confirmed that δ-MnO2 interaction was the dominant Mn removal mechanism. Our results show that δ-MnO2 contents could play a significant role in controlling Mn removability from mine water in the reactor.

Synthesis and Performance of PAFS Coagulant Derived from Aluminium Dross

Polymerised aluminium ferric sulphate (PAFS) was prepared from aluminium dross as a coagulant in wastewater treatment. The effects of leaching time, leaching temperature, and sulfuric acid concentrations on the turbidity removal of the wastewater were investigated, and the optimum conditions were determined using response surface methodology. The results showed that the optimum PAFS preparation conditions were at a leaching time of 60 minutes, a leaching temperature of 65°C, and a sulfuric acid concentration of 1 mol/L. Furthermore, experiments were performed to investigate the effect of coagulant dosages using the PAFS prepared under the optimum leaching conditions, settling time and initial pH of the wastewater on the turbidity removal efficiency. As a result, it was found that the optimum coagulation conditions for PAFS coagulants were at a settling time of 15 minutes, coagulant dosage of 0.5g, and raw water pH 8. Under these optimum conditions, the turbidity removal efficiency of the wastewater was 91.45%. The purpose of this study was to investigate the possibility of aluminium dross utilisation as a coagulant agent for wastewater treatment. Therefore, it can be concluded that PAFS prepared by leaching metal oxides from aluminium dross is an effective wastewater coagulant.

Geographical Variability of Bacterial Communities of Cryoconite Holes of Andean Glaciers

Cryoconite holes, ponds full of melting water with a sediment on the bottom, are hotspots of biodiversity on glacier surface and host dynamic micro-ecosystems on these extreme environments. They have been extensively investigated in different areas of the world (e.g., Arctic, Antarctic, Alps, and Himalaya), but no study so far has described the bacterial communities of the glaciers in the Andes, the world longest mountain range. In this study, we start filling this gap of knowledge and describe the bacterial communities of Southern Andes in three small (< 2 km2) high elevation (< 4200 m a.s.l.) glaciers of Central Andes (Iver, East Iver and Morado glaciers) and two large (> 85 km2) glaciers in Patagonian Andes (Exploradores and Perito Moreno glaciers) whose ablation tongues reach low altitude (< 300 m a.s.l). Results show that the bacterial communities were generally similar to those observed in the cryoconite holes of other continents. Indeed, the most abundant orders were Burkholderiales, Cytophagales, Sphingobacteriales, Actinomycetales, Pseudomonadales, Rhodospiarillales, Rhizobiales, Sphingomonadales and Bacteroidales. However, the bacterial communities differed between glaciers and both water pH and O2 concentration influenced the bacterial community composition.

Penerapan Sistem Monitoring Hidroponik berbasis Internet of Things (IoT)

Hydroponics is a method of planting without using soil media by utilizing water. The problem occurs when the farmer cannot control the water used in hydroponic. Therefore, we need a system to monitor the amount of water used in the hydroponic planting system. This service activity aims to develop and implement a hydroponic monitoring system based on IoT. This activity was carried out by students, followed by several accompanying lecturers. It aims to assist partners in measuring water content, temperature, and water pH in hydroponic plants. One of the business unit partners for this activity is SMEs engaged in hydroponic agricultural cultivation at the Science Technology & Industrial Park (STIPARK) NTB. This community service activity was held for four months. From the process of analyzing partner problems, they were testing the STIPARK management and hydroponic SME business partners and the community who later needed a hydroponic monitoring system based on the Internet of Things so that information could be received in real-time. This product can help hydroponic SME business partners know the level of water levels or nutrients, monitoring water temperature and water pH to help farmers increase crop yields from hydroponic cultivation.

Struktur Dan Komposisi Vegetasi Mangrove Di Kawasan Laguna Segara Anakan Cilacap

In coastal areas, mangrove communities have many functions economically, physically, and ecologically. One of the mangrove forest areas that is experiencing rapid decline in area is the Segara Anakan Lagoon, Cilacap. The purpose of this study was to determine the structure and composition of mangrove vegetation. Vegetation data was collected by purposive sampling method and each station was made 9 sampling plots. The results found that there are 12 species consisting of 4 major mangrove families, 1 minor mangrove family and 2 associated mangrove families. In general, the mangrove tree vegetation in the eastern part of Segara Anakan is dominated by Aegiceras corniculatum with an INP ranging from 38.99-67.23%, the middle part is dominated by Nypa fruticans with an INP ranging from 47.80-70.18% and the western part is dominated by Sonneratia alba with an INP of 56.32%. Environmental quality measures include water temperature, salinity, dissolved oxygen, soil pH, water pH, TSS, total soil N, organic C, soil phosphate still support mangrove life.

Structure and Distribution of Macrobenthos Community in Code River, Yogyakarta, Indonesia

This research aimed to explore the community structure of macrobenthos in Code River, Yogyakarta. This research was conducted during December 2019-January 2020 in Code River, Yogyakarta. Data was taken 4 times in 6 stations. Macrobenthos was taken using a Surber net with a size of 30 x 30 cm and sampling at 5 spots in each station. Data analysis consisted of density, diversity index, dominance index, and evenness index. Water quality data consisted of water temperature, flow velocity, water depth, water pH, dissolved oxygen, and organic matter. The results showed that the density of macrobenthos ranged from 54-172 ind/m2. Our results showed that Code River has moderate diversity based on the Shannon-Wiener diversity index. Sulcospira testudinaria is the most dominant species in Code River. The evenness index showed high except at station 2 which was categorized as moderate. Code River has pretty good water quality, but stations 3, 4, and 5 which are located in the city area, it has a high organic matter content.

Characteristics Environmental and Anopheles Larva Species In High And Low Clinical Malaria Cases In The Landak District of West Kalimantan Province

Malaria remains a health problem in Indonesia. West Kalimantan is a malaria endemic area with high and lowincidence. Landak District is one of the malaria endemic area. Malaria cases were found in the areas around illegalgold mining and oil palm plantations. The aims of this study were to describe the characteristics of the breeding sitesand species of Anopheles larvae found in high malaria cases area, namely Amboyo Utara Village and low clinicalmalaria cases, area namely Mandor Village. This research is a descriptive research with cross sectional design. Thesamples were Anopheles larvae collected with Accidental sampling technique in the breeding sites. Environmentalcharacterization of breeding sites were physical characteristic including water temperature and sun exposure,chemical characteristic including water pH and salinity, and biological characteristics including water biota. Theresults of this study ware environmental characteristics that have the potential to breed Anopheles mosquitoes inAmboyo Utara Village, including water temperature 26-30C, shandy, water pH 5.0-7.6, salinity 0.2-1.0 ppt, biotaswater hyacinth, grass and tadpole. The Mandor village, water temperature 29-30 ºC, shandy, pH of 6.9-8.0, salinity of0.5 ppt, water biota grass. Anopheles species found in Amboyo Utara village were larvae of An. vagus (94.30%), An.tessellatus (3.42%), An. subpictus (1.62%), An. indefinitus (0.81%) and An. maculatus (0.81%). Characteristics ofbreeding sites in Mandor village were larvae of An. maculatus (11.11%), An. subpictus (3.70%), and An. vagus(85.18%). The conclusion of this study was that di erent species found at breeding sites with di erent environmentalcharacteristics in both high and low malaria areas in Landak District, West Kalimantan Province.

Activation of Cadmium Under Simulated Solar Illumination and Its Impact on the Mobility of Cd in Flooded Soils

In waterlogged paddy soils, cadmium (Cd) can be precipitated as cadmium sulfide (CdS) under reductive environment, thereby limiting the absorption of Cd by plants. Multiple environmental factors (such as water, pH, Eh, etc.) played a role in the control of Cd mobility and bioavailability. In this study, we investigated the influence of the solar irradiation on the photo-dissolution of synthetic CdS-montmorillonite composites (CdS-M) in solution and the stability of Cdin natural soil. The release kinetic of Cd2+ showed that after the irradiation of simulated sunlight, CdS-M composites became less stable compared to the dark control. The solar irradiation seemed to enhance the release of Cd2+ from CdS significantly and continuously. Electron paramagnetic resonance (EPR) and quenching experiments confirmed that the photogenerated holes, O2·- and •OH were possibly involved in the photo-induced release of Cd2+, while the holes was primarily responsible for the reaction.Irradiation under alkaline solution or the presence of DOM, PO43-, CO32- and urea markedly inhibited the photodissolution process of CdS. The photo-mediated activation of Cd was further confirmed in paddy soil under natural sunlight, with a nearly 3-fold increase in concentration of extractable Cd during the 15 days irradiation. This study highlights the importance of photochemical transformation of Cd in the environmental water and soil.

Aristotle, Eleaticism, and Zeno’s Grains of Millet

This paper explores how Aristotle rejects some Eleatic tenets in general and some of Zeno’s views in particular that apparently threaten the Aristotelian “science of nature.” According to Zeno, it is impossible for a thing to traverse what is infinite or to come in contact with infinite things in a finite time. Aristotle takes the Zenonian view to be wrong by resorting to his distinction between potentiality and actuality and to his theory of mathematical proportions as applied to the motive power and the moved object (Ph. VII.5). He states that some minimal parts of certain magnitudes (i.e., continuous quantities) are perceived, but only in potentiality, not in actuality. This being so, Zeno’s view that a single grain of millet makes no sound on falling, but a thousand grains make a sound must be rejected. If Zeno’s paradoxes were true, there would be no motion, but if there is no motion, there is no nature, and hence, there cannot be a science of nature. What Aristotle noted in the millet seed paradox, I hold, is that it apparently casts doubt on his theory of mathematical proportions, i.e., the theory of proportions that holds between the moving power and the object moved, and the extent of the change and the time taken. This approach explains why Aristotle establishes an analogy between the millet seed paradox, on the one hand, and the argument of the stone being worn away by the drop of water (Ph. 253b15–16) and the hauled ship, on the other.