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EN
Microplastic (MP) has been a new emerging contaminant in the municipal water supply. A water treatment process is a key to producing high-quality and safe drinking water. The performance of a conventional drinking water treatment plant (CDWTP) to remove MPs is questionable. This research aimed to investigate the performance of 2 CDWTPs in East Java in removing MPs. Full-stage treatment in two CDWTPs consisted of intake, pre-sedimentation, coagulation-flocculation, sedimentation, sand filter, and disinfection units. Five L water samples were collected with a grab sampling technique in the sampling points of intake and outlet of each water treatment unit. MP abundance and characteristics in each sample were determined using a Sunshine SZM-45T-B1 stereomicroscope and a Nicolet i10 FTIR spectrophotometer. Total MP removal efficiencies in CDWTPs I and II were 66 and 62%, respectively. The coagulation-flocculation unit performed the highest MP removal efficiencies (56%). The MP with 1–350 μm size achieved lower removal efficiencies (33–53%) than that with 351-<5,000 μm size (53–76%). The removal efficiencies of fiber, fragment, and film in the CDWTPs were 61–65%; 86–100%; and 100%, respectively.
EN
Bacterial co-metabolism in composting process has been widely used to remove hydrocarbons, aided by in-situ production of bio-based surfactants, in terms of compost humic acid-like substances and biosurfactants. The properties of compost humic acid-like substances have been shown in previous studies as potential surface tension reducers and emulsifiers for hydrocarbons. The current study aimed to analyze the properties of biosurfactant of surface tension decrease, emulsification activity, and hydrocarbon solubilization ability. Four indigenous bacteria consortia were isolated from composted materials of yard waste, rumen residue, crude oil-polluted soil, and the mixture of polluted soil with organic waste (1:1, w/w) at day 0th, 20th, 40th, and 60th. Organic waste consists of yard waste and rumen residue in the ratio of 1:1. The isolated indigenous bacteria consortia were incubated for 7 days in different media, i.e., organic waste extract, 6.00% of crude oil, and a mixture of organic waste extract with 6.00% crude oil. The results indicated that the surface tension decrease and emulsification activity of biosurfactants were 8.35–52.90 mN m-1 and 0.00–12.00%, respectively, which showed the potential as surface tension reducers with low emulsification activity. The higher hydrocarbon solubility was shown by the biosurfactant from the rumen residue (13 620 µg g-1) and the mixture (10 998 µg g-1) at day 40th, which was comparable to 1.50% of Tween 80. The biosurfactants in the current research were produced with the same materials, process, and time as compost humic acid-like substances which acts as in-situ bio-based surfactants. The respective ability to solubilize hydrocarbon might be combined and estimated to be higher than Tween 80 of 24 329 µg g-1 and 21 619 µg g-1 for rumen residue and the mixture, respectively. Therefore, it was concluded that the best composition for in-situ bio-based surfactant production to assist the degradation of hydrocarbon through composting process is polluted soil with organic waste (1:1, w/w). The solubility of hydrocarbons can be increased without synthetic surfactants addition, but through providing nutrients to maintain in-situ bio-based surfactant production with intermittent addition of organic waste every 40 days. This method is expected to be an appropriate approach in composting development as a cost-effective sustainable bioremediation technique for polluted soil.
EN
The abundance of microplastics (MP) in the aquatic environment is increasingly disturbing for maritime countries, especially Indonesia, because it has the potential to threaten the health and sustainability of aquatic ecosystems. This review summarized and discussed the distribution of MP abundance in Indonesian aquatic ecosystems which concluded that rivers, bays and estuaries, beaches, seas, and even fish and shellfish have been contaminated. The highest contamination of MP was found in the waters of Jakarta, West Java, and East Java, which are densely populated areas. The potential threat of exposure and accumulation of MP to human health was also discussed. However, differences in the methods and units of measurement for MP as well as limited information regarding the interaction of MP with human organ functions are weaknesses in this review. The future research on the relationship between food and feeding habits of the community around contaminated waters with the accumulation of MP in the human body is needed to identify the prevention and treatment strategies.
EN
The use of aluminum sulfate (Al2SO4) coagulant in water treatment plants generates large amount of sludge residues containing the alum hydroxide precipitates and organic matter. Due to its amphoteric characteristic, this sludge by-product offers alum coagulant recovery by using electrochemical process, before safe disposal to the environment. This study is aimed at evaluating the efficiency of membrane-based electrochemical processes to recover aluminum from the filtrate of the acidified sludge. The dried alum sludge was acidified using sulfuric acid at pH 3, and then centrifuged to obtain the filtrate. Organic content of the filtrate was measured by means of Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD), i.e., 295.8 mg/L and 9,666.7±942.81 mg/L, respectively. In addition, the concentration of Al, Fe, Cu, and Cr was 1,194 mg/L, 515 mg/L, 0.559 mg/L, and 0.217 mg/L, respectively. The two-compartment electrochemical reactor was separated by using Cation Exchange Membrane (CEM) and Anion Exchange Membrane (AEM), and operated in a batch system for 10 hours with an electrical current of 300 mA. The results showed that the use of CEM in electrolysis with the electrodes distances of 1 cm increased the aluminum recovery up to 66.74% with the TOC removal of 24.04% compared to the use of AEM. An electrochemical process using CEM can be suggested to obtain organic-free recovery stream containing higher recovery of alum.
EN
The mercury-containing tailing waste from public gold mines in Indonesia is generally deposited on soil without treatment. This research aimed at determining the amount and composition of mercury species in the tailing, and testing the effect of sulfur and sulfide on mercury stabilization. Samples were collected from a tailing pile at different depths in a public gold mine in Kulon Progo, Indonesia. The samples were characterized according to the mercury concentrations and Toxicity Characteristic Leaching Procedure (TCLP) test. Mercury speciation was carried out using nitrogen gas flow into tailing samples, which were placed in three test tubes. The released mercuric species was entrapped in KCl and KmnO4 solutions. The mercury stabilization was carried out using sulfur and sodium sulfide. TCLP test was performed to the stabilization products. The mercury concentrations were measured using a mercury analyzer. The results showed that the mercury in the tailings were dominated by elemental Hgo, the concentrations of which in the tailing piles of 30, 60, and 90 cm depths were 74.7%, 71.6%, and 76.5% respectively. Those of ionic Hg2+ form were 25.3%, 28.4%, and 23.5%, respectively. Additions of sulfur powder and sodium sulfide solution produced stable black-colored mercury sulfide. When compared to sulfide, sulfur was more recommended for stabilizing mercury in the tailing waste.
EN
Untreated alum sludge from Surabaya water treatment plant (WTP), which contained high concentration of alum was directly discharged into Surabaya River. It might cause problems because of the accumulation of aluminum in the lower part of the river. Alum could be recovered from the drinking water sludge using the electrolysis method. Aims of this study were to determine the optimum pH and electrical current for electrolysis using carbon-silver electrodes to recover aluminum coagulant from the sludge, and to determine the amount of the recovered alum. The sludge was acidified prior to electrolysis. Acidification was done by adding sulfuric acid at pH 3 and 4. Polarization test was conducted at 100, 200, and 300 mA, in order to determine the optimum electrical current. The electrolysis was performed in one compartment batch recirculation reactor, using silver as cathode and carbon as anode for 10 hours. Values of pH were measured every hour. The precipitated matter in the cathode was weighed, and analysed by means of Inductively Coupled Plasma. The optimum conditions of the electrolysis were achieved at initial pH 3 and electrical current 300 mA. The electrolysis resulted in the highest precipitate of 2.6112 g in the cathode.
EN
The presented study concerns on isolation and identification of indigenous bacteria in total petroleum hydrocarbon (TPH) polluted soil. The composite TPH polluted soil was collected from Wonocolo public oilfields, Indonesia. Pour plate and plate count techniques were used to bacterial population analysis and enumeration, respectively. Two dominant bacterial colonies were isolated from 4.06x107 CFU/g population in polluted soil, then morphologically and biochemically were characterized using Microbact Identification Kits (MicrobactTM GNB12A and 12B). The identification of isolated bacteria was performed using Bergey’s Manual of Determinative Bacteriology. The results showed that the strains of bacteria are Bacillus sp. and B. cereus with probability of 72.00 and 77.00%, respectively. These strains potentially acted as biosurfactant producers and hydrocarbon degraders. Thus, biostimulation could be implemented to reduce the TPH levels in polluted soil at Wonocolo public oilfields.
EN
A conventional water treatment plant (WTP) typically involves coagulation-flocculation processes to remove suspended particles and colloids in raw water. The process generates a large volume of alum sludge with high aluminum content, which is discharged into a river with improper treatment. The sludge may cause a potential risk to human health, and disrupt the life of river biota. The aims of this study were to determine the physical and chemical characteristics of alum sludge from Surabaya WTP, and to compare them with those of alum sludge from other plants in Indonesia and developing countries. The alum sludge sample was obtained from the Surabaya WTP in Indonesia. The results showed that the alum sludge had a pH value of 7.47, volatile solids of 12,696 mg/L, total suspended solids of 12,511 mg/L, chemical oxygen demand (COD) 9666.7 mg/L, biochemical oxygen demand (BOD) 1082.5 mg/L, and sludge volume index 114.18 mL/g. The sludge had high aluminum and iron concentrations. The aluminum content of the sludge was 1194 mg/L, iron 515 mg/L, chromium 0.217 mg/L, and copper 0.559 mg/L. Having a BOD/COD ratio of 0.1, the alum sludge contained high level of nonbiodegradable organic matter.
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