Effect of inoculated and uninoculated aeration pretreatment on nutrients and phytotoxicity of anaerobic digestion effluent.

This study investigates the influence of inoculated and uninoculated aeration pretreatment on nutrients and phytotoxicity of anaerobic digestion (AD) effluent. Swine manure AD effluent was inoculated with activated and anaerobic sludge, respectively. Our results show that aeration with the addition of activated sludge could reduce the phytotoxicity of AD effluent. Compared to the control treatment without any sludge addition, the addition of activated sludge resulted in a more significant reduction in the AD effluent salinity, NH4+ content, and organic matter (indicated by the chemical oxygen demand) when AD effluent was aerated for less than 8 hours. As a result, a much higher seed germination index (GI) was observed for the treatment with activated sludge addition, particularly when aerated for 4-5 hours, contributing the gas/water ratio of 20:1-30:1. On the other hand, no significant differences in the nutrient contents and GI value were observed for the control treatment and that with the addition of anaerobic sludge. Results from this study shed light on optimizing the management of AD effluent for agricultural application.

Effects of sludge enhanced aeration on nutrient contents and phytotoxicity of anaerobically digested centrate.

In this study, we investigated the impact of intensive aeration pre-treatment on nutrient contents and phytotoxicity of anaerobically digested manure centrate. Activated sludge from conventional wastewater treatment plants was added to reinforce the aeration process. Results show that the addition of activated sludge did not negatively affect the nutrient contents, but significantly reduced the phytotoxicity of digested centrate, as indicated by an enhancement of seed germination index, during the aeration treatment. Based on the orthogonal experiment and following statistical analysis, the lowest phytotoxicity of digested centrate could be achieved under the aeration conditions: sludge concentration of 6 g/L, aeration time of 2 h, gas/water ratio of 40:1, and pH = 6.5. Of these operational parameters, the digested centrate pH dominantly determined its nutrient contents (e.g., amino acids, total phosphorus, and ammonium) and phytotoxicity. These results were further verified by hydroponic experiments, which showed that using digested centrate after sludge enhanced aeration as the nutrient solution facilitated the growth and dry biomass of maize.

[Effect of alpha-naphthlcetic acid on the proliferation and apoptosis of testis cell].

OBJECTIVE: To investigate the effect of alpha-naphthlcetic acid on the proliferation and apoptosis of testis cell. METHODS: Twenty five mice were divided into five groups, 5 mice per group. Basal animal food was fed to the mice in the normal control and positive control groups. Five thousand, 1000, 200 mg/kg of alpha-naphthlcetic acid were added into another three groups. Three days before sacrifice, the mice in positive control group were intraperitoneally injected with cyclophosphamide of 20 mg/kg each day. Four weeks later, all the mice were sacrificed. The proliferation activity of the testis cells was determined by MTT assay, and the levels of Caspase-3 and PCNA protein expression in testis cell were measured by immunohistochemistry method. RESULTS: The testis cell proliferation activity of the high dose group and the normal control group were 0.501 +/- 0.069 and 0.875 +/- 0.082. The difference was significant (P < 0.05). The expression level of PCNA protein and Caspase-3 of the high dose group were 8.9% and 41.3%, respectively, and those of the normal control group were 34.9% and 9.1%. The differences between two groups were significant (P < 0.05). CONCLUSION: alpha-naphthlcetic acid can inhibit the proliferation and induce the apoptosis of testis cells effectively.