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3 Journal of Ecological Engineering

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Recovery of Alum from Surabaya Water Treatment Sludge using Electrolysis with Carbon-Silver Electrodes

100%

Barakwan R. A. , Hardina T. T. , Trihadiningrum Y. , Bagastyo A. Y.

tom Vol. 20, nr 7

126--133

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.

Microplastics Contamination in the Aquatic Environment of Indonesia: A Comprehensive Review

100%

Sari G. L. , Kasasiah A. , Utami M. R. , Trihadiningrum Y.

Journal of Ecological Engineering

2021

tom Vol. 22, nr 10

127--140

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.

Biosurfactant Produced by Indigenous Bacteria During Composting Process of Crude Oil Polluted Soil: Properties and Role

75%

Sari G. L. , Trihadiningrum Y. , Ni'matuzahroh , Putra S. A. , Kasasiah A. , Alim M. S.

tom Vol. 23, nr 4

297--314

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.