VIBRATION AND ELECTRO COAGULATION FOR REMOVAL OF ALGAE IN RAW WATER CONTAMINATED WITH DOMESTIC WASTE

• Main Author: Darmasetiawan, Martin
• Format: Dissertations
• Language: Indonesia
• Subjects: Teknik saniter dan perkotaan; teknik perlindungan lingkungan
• Online Access: https://digilib.itb.ac.id/gdl/view/75223
• Institution: Institut Teknologi Bandung

Currently, there is an increase in settlements due to urbanization along the North Coast of Java Island, resulting in a scarcity of raw drinking water resources, especially during the dry season. Alternative sources of raw water and drinking water come from several reservoirs and ponds that serve to collect water from rainwater and domestic wastewater, primarily located upstream. As a consequence of these conditions, these water bodies are generally contaminated with domestic wastewater, leading to eutrophic conditions where algae havegrown and thrived. Therefore, alternative treatment methods such as vibration and electrocoagulation processes are employed to remove algae from the pollutedraw water. This study is conducted in four phases: understanding the characteristics of the water bodies, investigating the relationship between ultrasonic cavitation and algae in batch conditions, examining the effects of ultrasonic treatment in batch conditions, and finally, applying the developed system in continuous conditions. To determine the characterization of the water bodies, water samples were taken from wastewater pondsin ITDC-Nusadua-Bali, Bojongsoang-Bandung West Java, KBN (Kawasan Berikakat Nusantara) Cakung DKI Jakarta, and Situ Rawa Binong Cikarang Kabupaten Bekasi West Java. As secondary data, water samplesfrom Waduk Soedirman in Banjarnegara Central Java, Myrose India, and Lyndoch Australia were used. Next, data processing was conducted using a quantitative descriptive and comparative descriptive approach. The survey method was employed with exploratory techniques. Quantitative descriptive analysis was used to examine the relationship between the BOD parameter, which describes biodegradable organic matter, and the N/P molar ratio with dominant algae. The analysis method used graphical mapping of BOD, N/P molar ratio, and the k-nearest neighbor (k-NN method The conclusion of the first phase of the research is that high BOD and high N/P ratios indicate the likelihood of Euglena, Crococcus, Oscillatoria, and microcystis algae growing and dominating. High BOD with low N/P ratio indicates the likelihood of Spirulina, Chlorella, and microcystis algae. Low BOD with high N/P ratio indicates the possibility of Chlorella, Crococcus, Spirulina, and microcystis algae. Finally, low BOD with low N/P ratio suggests the potential growth of Spirulina, Chlorella, and microcystis algae. The second phase of the research aimed to understand the relationship between ultrasonic cavitation and algae in water. Ultrasonification of water-algae can be enhanced by creating a vacuum above the water surface. This phenomenon is expressed in an equation that relates negative pressure on the water surface, transducer depth, ultrasonic power at a specific frequency, and a certain time. The obtained equation is considered a pseudo-first-order equation. Then research on the ultrasonic process was conducted in batch conditions in a transparent glass tube, ultrasonicated by a 20 kHz transducer for 30 minutes followed by electrocoagulation. The tube was vacuumed between -0.33 to -1 atmosphere using a manual vacuum. Data were taken at transducer depths of 0.06, 0.13, and 0.19 m. The results of Phase III showed that vacuuming the algal solution would provide an increased lytic effect compared to the ultrasonic process at ambient pressure. Furthermore, the transducer depth was another factor that could enhance algal cell lysis. The lower the depth, the greater the lytic effect. Therefore, it can be concluded that electrocoagulation preceded by ultrasonic treatment would improve algal removal efficiency by 4-9%. The results of Phase IV involved the implementation of the ultrasonic and vacuum processes under continuous conditions. It can be concluded that increasing negative atmospheric pressure and the power-to-area ratio, as well as the depth, would enhance the algal reduction process, causing cell rupture and reducing the biomass density. Meanwhile, the success of the electrocoagulation process is directly proportional to the power magnitude of electrification and the duration of electrification, but inversely proportional to the electrode spacing. The most influential factors in the ultrasonic process are negative pressure and the depth of the ultrasonic transducer. The success of the electrocoagulation process depends greatly on the electrode spacing and the electrode surface area, in other words, the electrode spacing, as well as the required current and voltage magnitude. By combining vacuuming up to -0.90 atmospheres with the ultrasonic process, the electricity consumption in the electrocoagulation process decreased by up to50%.