One of the most promising areas with the existence of the lake is Universitas Indonesia. Universitas Indonesia (UI) has six lakes with a total area of 269,107 m2 which is very important for its existence to balance the surrounding environment. Currently, the existence of UI lake has been contaminated with the COD value of about 1 to 8.000 mg/L due to a lot of garbage that enters and buried in it, that more attention is needed so that pollution will not increase. Microbial Desalination Cell (MDC) is a development system of Microbial Fuel Cell (MFC), which has the ability to desalinate seawater and can produce electricity by using microorganisms as waste decomposers. In addition, MDC method can also reduce the level of waste contained in the substrate used. To improve the performance of MDC, this study utilizes bio charcoal from rice husks to assess the performance of sodium percarbonate in the cathode chamber with a variation of 0.05 M concentration; 0.1 M; 0.15 M; and 0.2 M, and the performance of the addition of bacteria consortium on the substrate. The best results of this MDC study, in the variation of 0.15 M sodium percarbonate concentration with a decrease of COD and BOD of 93.98% and 87.67% and in variation of addition of bacteria consortium of 1 mL with decrease of COD and BOD 90.04% and 50.52%.

Microbial Desalination Cell (MDC) is one of a Bio Electrochemical technology and also modification technology of Microbial Fuel Cell (MFC), MDC is a method that desalinate a sea water. In the use of this MDC system, the bio electrode that use is from coconut shell charcoal. The use of charcoal as Bio Electrode because it has a low cost as well as environmentally friendly, and charcoal doesn’t have some toxic properties. Another problem besides the use of bio electrode, is the imbalance between the pH and the chamber becomes another obstacle to the MDC system and the impact of some approaches leads to increased cost of capital and operational costs. In order to overcome these barriers by cost, Lake UI is used as the substrate and Sodium percarbonate (SP or 2Na2CO3∙3H2O) also used as a natural buffered electrolyte. Based on the results of variations of SP concentration, best concentration of SP was at 0.15 M (SR=15.14%), concentration NaCl at 35 g/L were able to reduce the mass of 3.626 g to 3.077 g with salinity 30.77 g/L.

Denitrification is the conversion process of nitrate to gaseous nitrogen forms carried out by bacteria commonly referred to as denitrifiers. Microbial Electrolysis Cell (MEC) is a type of bioelectrochemical system (BES) that is connected to external power source to aid the reactions. This research investigates the effect of applied voltage value on denitrification by nitrate removal efficiency of two model denitrifying species from the genus Pseudomonas in single-chambered MEC. Pseudomonas aeruginosa and Pseudomonas nitroreducens exhibited native removal efficiency at 70.62% and 68.20%, respectively. These values respectively reached up to 89.67% and 88.58% at 1.20 V, the upper limit of this study. Pseudomonas aeruginosa displayed better performance in MEC based off its produced current stability (mA) across the 0.35-1.20 V range. The effect of applied voltage on nitrate removal efficiency and setup performance was more prominent on known exoelectrogenic species of Pseudomonas such as Pseudomonas aeruginosa compared to Pseudomonas nitroreducens. Operating applied voltages of 0.35 V and 0.70 V was recommended for the application of the system based on technical and economical considerations. Further studies are needed to determine the response of the bacteria on wider range of applied voltages in MEC as well as elucidating these effects on autotrophic systems.