[Strengthening Effect of Different Cattail Pretreatment Methods on the Denitrification of Horizontal Subsurface Flow in a Constructed Wetland].

Nitrogen removal in constructed wetlands (CWs) is highly affected by the supply of organic carbon. Thus, to enhance nitrogen removal in the horizontal subsurface flow of CWs, plant carbon sources were added during the downstream portion of the wetland. Moreover, the characteristics of static release and the denitrification potential of Typha were evaluated using three different pretreatment methods (i.e., minced, acid-heated, and alkali-heated). The average concentrations of COD released and the nitrate removal rate with the alkali-heated, acid-heated, and minced Typha were 89.57 mg·L-1 and 75.2%, 67.27 mg·L-1 and 67.2%, and 54.45 mg·L-1 and 23.5%, respectively. The results showed that different pretreatment methods resulted in the release of different amounts of acetic acid, and the alkali-heated Typha performed much better than the other pretreatments. Therefore, the alkali-heated Typha was selected and added to the middle of the horizontal subsurface flow CW, which improved the nitrogen-removal rate significantly; the average removal rate of TN and TP was higher than that of a control CW by 30.3% and 33.9%, respectively. However, the COD concentration of the CW with the alkali-heated Typha was not significantly increased.

[Determination of lead and arsenic contents in amylum by ICP-AES methodology].

Lead and arsenic contents in amylum were determined by ICP-AES (inductively coupled plasma atomic emission spectroscopy) method with the addition of Ni(NO3)2 as the matrix modifier. Detailed discussion was conducted about the impact of factors such as ashing and automation temperature, ashing method of samples, and matrix modifier on the experimental results. The experimental results showed that ICP-AES method is easy, rapid and exact, its return character is good, and it can be used in the inspection of heavy metals such as lead and arsenic in amylum.

Screening and enzymatic study of a composite microbial system FH3

Five strains of fungi and 18 strains of bacteria were isolated from the soil and horse manure with cellulose as the sole carbon source. Among them, two fungal, F9 and F13, and two bacterial, B16 and B21, showed the highest filter paper activities, which were 7.79 U g-1, 9.84 U g-1, 7.34 U g-1 and 9.68 U g-1, respectively. Four microbial systems, designed as FH1 (F13+B21), FH2 (F13+B16+B21), FH3 (F9+B16+B21) and FH4 (F13+F9+B16+B21) were developed. The fermentation studies showed that the filter paper activity of the composite microbial system FH3 was higher than the others, which was 21.34 U g-1. The medium with bran and filter paper as the carbon source and peptone as nitrogen source was optimal and the maximum cellulase activity was reached at 30~35ºC and pH 6.0~6.5 when FH3 was incubated for 48 h. The enzymatic reaction conditions were estimated at 45~55 ºC, pH 4.5~5.5 and the thermal stability temperature was up to 60 ºC.