Jen-Jeng Chen

Effects of Backwashing on the Characteristics of Sand Filtration Effluents: Organic and Microbial Analyses

In this study, the head loss, turbidity, particle size, and zeta potential were monitored from the effluent of the sand filtration system after backwashing located in Cheng-Ching Lake (CCL) Water Treatment Plant. Moreover, the non-purgeable dissolved organic matter (NPDOC) and excitation emission fluorescent matrix (EEFM) were measured for the collected water samples with or without the pretreatment process. Results indicate that the turbidity of the influent dropped to 0.06 NTU and remained stable after flowing through the sand filter during the 4-hr operation period. However, a continuous increase of the head loss and sand particle size for the sand filter was observed. This phenomenon was opposite with the absolute value of zeta potential. The water samples were collected from the effluent of the sand filter and were treated by a 0.2 μm membrane filter. Thus, higher NPDOC values of sample without pretreatment were observed in comparison with sample with treatment. Results indicate that the sand filter was able to remove NPDOC, and bacteria might proliferate among the sand filter in rapid filtration. Results from the EEFM analyses show that effluents without membrane filtration pretreatment contained a higher percentage of aromatic protein. Compared to the water samples without pretreatment, more humic-like substance was found in the effluent. This reveals that microbial products or bacteria were detached from the fillers after the backwashing process.

Spectrometric Characteristic of Superficial Chlorella Sp. Grown in Photo-Bioreactor under Different Flow Rates

In this study, photo-bioreactor designed with 4 L of volume to cultivate Chlorella sp. was conducted for comparing the differences of biomass increase among three gas flow rates. All experiments were controlled at light reaction of 12 hrs. with 1,700 lux. The organic fluorescence of algae, expressed in excitation emission fluorescent matrix (EEFM), was obtained from algal solution deducted from EEFM of the filtrate obtained from the filtration of algal solution using 0.2 μm membrane filter. Also, the surface charge and functional group for Chlorella sp. were respectively measured by zeta meter and Fourier transform infrared spectroscopy (FTIR). Biomass was measured by absorbance wavelength of 683 nm or dried biomass. Current results reveal that high flow rate produced more biomass than low flow rate did. Regarding to the fluorescent characteristic derived from Chlorella sp., two peaks were appeared in both wavelengths of excitation and Emission (EX/EM) respectively located at 280/330 nm (protein-like) and 440-480/680 nm (pigment). For the variation of autofluorescent intensities during algal incubation, algal image captured by epofluorescent microscope equipped with CCD (Charge-Coupled Device) could be further dealt using image software, showing that there were divergences of fluorescent intensities derived from varied amount of protein-like substance or pigment. Functional group of Chlorella sp. analyzed by FTIR, hydroxyl, peptidic bond, carboxylic acids and polysaccharide were existed with variations of transmittance (%) while gas flow rate was changed.

Nitrogen and Phosphorus Removal and Biomass Production by the Green Microalgae in Piggery Wastewater

Use of microalgae to remove inorganic nutrients from wastewater and their great potential for low-cost biomass production is gaining attraction. The effect of piggery wastewater content, aeration rate, cultivation temperature, and light intensity on nitrogen and phosphorus removal and biomass production were studied by using a Box-Behnken experimental design under full factorial methodology. Under experimental conditions considered cultures with aeration increased the ammonium and orthophosphate removal efficiency up to an average of 65.3±17 % and 51±7.2 %, respectively and an increase of biomass productivity ranging from 20.8±11 mg/L.d to 52.3±5.5 mg/L.d. The aeration rate was the most important factor influencing the nutrients removal and biomass production.

Seasonal Variations of Heavy Metals in the Bivalve’s mollusks from Ta-Peng Bay Lagoon in Southwestern Taiwan

Ta-Peng Bay lagoon in southwestern coast of Taiwan belonging to a shallow, productive, coastal lagoon was heavily polluted by the effluent of agriculture from fisheries and domestic sewage. This area provided a plentiful bivalves mollusks for regional market, including Anadara antiquate, Katelysia hiantina, Perna viridis and Anomalocardia squamosa. For understanding correlation between heavy metals existed in aquatic product and variation of heavy metal varied with season, during Dec., 2005- Sep., 2006, six heavy metals, such as Cu, Zn, Pb, Ni, Cr and Cd were analyzed by an air-acetylene flame / Graphite Atomizer atomic absorption spectrophotometer. The variations of different heavy metals existed in aquatic product in season were evaluated using multivariate analysis. Results show that the mean concentration of heavy metal in soft tissues for six aquatic products, Cd species had the lowest value than the others, and Cu and Zn were significantly higher than the other elements. The relationships of all heavy metal species in seasonal variations showed significant dependence. High concentrations of heavy metals were observed in winter. The negative correlation coefficient (p < 0.05) between heavy metals content and season variations statistically revealed decreased with season series for Ni, Pb, and Cr. An interesting finding that Cd bioaccumulation among the species had a significant discrepancy was observed. It means that bivalves mollusks could be develped as a potetial tool for monitoring Cd species.

The Divergences of Organic Matter Released from Ozonated Biofilter Inoculated with Indigenous Bacteria

In this work, the excitation-emission fluorescent matrix (EEFM) was used to compare the divergence of fluorescent organic properties of the effluents produced from the operation of the bio-stabilizing filter. Four bio-stabilizing filters were simultaneously operated in the combination of both filtered CCL and FS source waters with ozonation (O3/NPDOC=1) and two different indigenous bacteria taken from CCL and FS source water. It found that, two peak locations, 220-230/330nm, 320-330/410-420nm, existed in the effluent of the four bio-stabilizing filters, and one another peak of 280-290/340 nm was appeared in bio-stabilizing filter using FS source water as a substrate. The fluorescent organic matter, with an excitation wavelength of 220-230 nm and 280-290 nm may be attributed as protein-like, while that of 320-330/410-420nm had the possibility of humic-like. The humic-like matter was accumulated in the effluent from the bio-stabilizing filter during the operational process. Bio-stabilizing filter operated with consistent source water and indigenous bacteria could release higher humic-like fluorescent intensity than that with inconsistent source water and indigenous bacteria.

Effects of Chlorine Dioxide on the Bioactivity of Planktonic and Attached Bacteria Grown in Annular Reactor System

Annular reactor; Epifluorescent microscope; Adenosine triphosphate(ATP)；Chlorine dioxide; Abstract: The artificial solution, including organic molecular weight cut-off less than 5 K added indigenous bacteria taken from biofilter conducted in bench-scale experiment, was drawn by peristaltic pump pumped into Annular Reactor system (ARs) with flow rate 20 mL/min and rotating velocity of 134 rpm. ARs could reach stable at the operational time of 40 hrs. Then, chlorine dioxide was added into ARs to keep system consisting of three chlorine dioxide dosages , including 0.5, 1.0 and 1.5 mg-ClO2 as Cl2/L. Live-Dead microorganisms in this research were measured using both kinds of dye, such as CTC (5-cyano-2,3-diolyl tetrazolium chloride) and DAPI (4’,6-Diamidino-2-phenylindole dihydrochloride), observed under fluorescence microscopy having G-2A filter (EX 510-560 nm, DM 575, BA 590 nm) for CTC, and UV-2A (UV-2A (EX 330-380 nm, DM 400 nm, BA 420 NM) for DAPI. Of course, the measurement of ATP (Adenosine triphosphate) was used as another parameter to evaluate the bacterial activity. Current data shows that when initial chlorine dioxide of 0.2 mg-ClO2asCl2 /L could not effectively control the bacterial cells, especially that the remaining dosage decreased to zero at longer reaction time. In contrast with low chlorine dioxide dosage, 1.0-1.5 mg-ClO2asCl2 /L could not only control the planktonic bacteria but also inhibit the growth of respiring cell attached on the slide. Parameter using Dead-Live cells and ATP to express bacterial activity could show the similar performance while chlorine dioxide was applied into ARs.