Advanced Treatment of Campus Sewage...
249
3 Materials and Methods
3.1 Water Samples for Test
The water samples were taken from the membrane bioreactor (MBR) effluent in the
sewage treatment station at Sunshine Campus of Wuhan Textile University (Wuhan,
China), and the water quality is shown in Table 1. This work focuses on disinfection,
decolorization, and deodorization.
3.2 Experimental Device and Procedure
For short lamps the useful emission length is proportionally shorter than for long
lamps because of the Faraday dark space of about 1-cm length on the cathode side.
To compensate for short low pressure Hg lamps, we used U-shaped other than bent
lamps for experiment (Masschelein and Rice 2002). The low pressure electrodeless
UV lamp produces more ozone than that of the medium pressure lamp. When the
microwave power is set to 800 W, eight low-pressure electrodeless UV lamps (Ø15
× L600) will generate a total light intensity of 4.38 mW/cm
2 , which reaches the
maximum of absorbing microwave power. Under this condition and with an air pump
ventilation of 20 L/min, 0.202 mg/L of ozone can be produced, which corresponds
to a generation rate of 4.04 mg/min or 242.4 mg/h. Further increasing lamp number
shows no effect on the total light intensity and ozone production.
As is shown in Fig. 1, the experiment device is a laboratory-scale MW/UV/O 3
reactor with an effective volume of 1 L. The reactor is comprised of a microwave
irradiation zone and a reaction zone. The microwave generator is installed in the
upper part of the reactor, and the electrodeless UV lamps are evenly arranged all
over the reactor. A self-made controller can be used to adjust the power of the
microwave. Microwave radiation raises the temperature inside the reactor, so this
device is designed to recirculate externally to control the temperature. The water
will be cooled in the external condensing system and then returned to the MW/UV
reactor for a recirculation.
3.3 Water Quality Analysis
The determinations of water quality indices such as Chemical Oxygen Demand
(COD), Biochemical Oxygen Demand (Herridge et al. 2008) total nitrogen (TN),
ammonia nitrogen (NH 3 –N), total phosphorus (Sekar et al. 2004), and chroma were
according to the standard methods (Fu et al. 2012; State Environmental Protection
Administration 2002). The total number of bacteria was determined using the dilution
spread plate method (Cheng et al. 2018). The odor threshold was measured by the
249
3 Materials and Methods
3.1 Water Samples for Test
The water samples were taken from the membrane bioreactor (MBR) effluent in the
sewage treatment station at Sunshine Campus of Wuhan Textile University (Wuhan,
China), and the water quality is shown in Table 1. This work focuses on disinfection,
decolorization, and deodorization.
3.2 Experimental Device and Procedure
For short lamps the useful emission length is proportionally shorter than for long
lamps because of the Faraday dark space of about 1-cm length on the cathode side.
To compensate for short low pressure Hg lamps, we used U-shaped other than bent
lamps for experiment (Masschelein and Rice 2002). The low pressure electrodeless
UV lamp produces more ozone than that of the medium pressure lamp. When the
microwave power is set to 800 W, eight low-pressure electrodeless UV lamps (Ø15
× L600) will generate a total light intensity of 4.38 mW/cm
2 , which reaches the
maximum of absorbing microwave power. Under this condition and with an air pump
ventilation of 20 L/min, 0.202 mg/L of ozone can be produced, which corresponds
to a generation rate of 4.04 mg/min or 242.4 mg/h. Further increasing lamp number
shows no effect on the total light intensity and ozone production.
As is shown in Fig. 1, the experiment device is a laboratory-scale MW/UV/O 3
reactor with an effective volume of 1 L. The reactor is comprised of a microwave
irradiation zone and a reaction zone. The microwave generator is installed in the
upper part of the reactor, and the electrodeless UV lamps are evenly arranged all
over the reactor. A self-made controller can be used to adjust the power of the
microwave. Microwave radiation raises the temperature inside the reactor, so this
device is designed to recirculate externally to control the temperature. The water
will be cooled in the external condensing system and then returned to the MW/UV
reactor for a recirculation.
3.3 Water Quality Analysis
The determinations of water quality indices such as Chemical Oxygen Demand
(COD), Biochemical Oxygen Demand (Herridge et al. 2008) total nitrogen (TN),
ammonia nitrogen (NH 3 –N), total phosphorus (Sekar et al. 2004), and chroma were
according to the standard methods (Fu et al. 2012; State Environmental Protection
Administration 2002). The total number of bacteria was determined using the dilution
spread plate method (Cheng et al. 2018). The odor threshold was measured by the