The Study of micro-bubble Generator on Aerobic Waste Water Treatment using Bio-Ball Method, Based on The Bubbling Generating Condition and The Configuration of Micro-bubble Generator

• Main Authors: , Anggita Gigih W.I., , Dr. Eng. Deendarlianto ST, M.Eng
• Format: Theses and Dissertations NonPeerReviewed
• Published: [Yogyakarta] : Universitas Gadjah Mada 2014
• Subjects: ETD
• Online Access: https://repository.ugm.ac.id/128709/; http://etd.ugm.ac.id/index.php?mod=penelitian_detail&sub=PenelitianDetail&act=view&typ=html&buku_id=69075
• Institution: Universitas Gadjah Mada

A further study has been conducted to analyse the optimum design of Microbubble generator (MBG). MBG with porous pipe and orifice (PO), MBG with porous pipe and spherical body (PB), and MBG with spherical body and drilled holes (DB), were investigated in this experiment. The micro-bubble generator is placed at a depth of H = 40 cm from the surface of water. Three different pressure transducers were placed around the micro-bubble generator body to analyze the inlet water pressure PL, the air suction pressure, PG, and the pressure at the outlet of micro-bubble generator. The output signals from above sensors were sent to a personal computer via an A/D converter to determine the respective time-averaged values. The water was supplied from centrifugal pump from QL= 2 m3 /hour until QL= .5 m3 /hour, with the air suction rate QG was form 0.1 l/min until 0.8 l/min. The water flow rate ,QG, and the air suction rate, QL, were measured by calibrated flowmeter and controlled by a gate valve .The bubble diameter was measured by capturing the bubble pictures using digital camera CANON EOS 550 D with additional 100m macro lens, and analyzed by image processing technique using MATLAB. The hydraulic power, the bubble generation efficiency and dissolved oxygen number were defined as parameters of the performances of micro-bubble generator. The study revealed that the bubble intensity increased with the increase of water supply rate, and found that MBG with porous pipe and orifice was the optimum designs in producing micro-bubble, although it required more power. From these experiments, we succeeded in producing micro-bubble sizes ranging between 50 to 200 µm. In order to simulate the application of micro-bubble Generator in the field, the study on the effect of micro-bubble configuration and the feasibility test in the application in aerobic waste water treatment have been performed. The result showed that the bigger the number of MBG that used, the better the ability to increase the oxygen, and it�s necessary to arrange the placement each MBG in the configuration in order to minimize the coalescence bubbles so the fluid can hold the DO number in longer time. Furthermore the feasibility test in micro-bubble application in aerobic waste water treatment by using bio-ball as the porous media for microorganism attachment, show a promising result, it can reduce the number of COD in 354 mg/l in average, although it�s still lower than our expectation. The number of the DO is always larger than 2 mg/L, the pH level is always at 6, and the temperature is not more than 350 C.