[The inherent toxicity of organic extracts in the effluents treated by present treatment and the new process].

OBJECTIVE: Evaluate the inherent toxicity of organic extracts in the effluents treated by present treatment and the new process find the scientific evidences of the new wastewater treatment technique to compare the removal efficiency of trace organic pollutants. METHODS: The Solid Phase Extraction was adopted to enrich the trace organic pollutants in the water samples with resin adsorbing, then detected the inherent toxicity of them by using Vicia faba root-tip micronucleus test and single cell gel electropheorsis test. RESULTS: After concentrated 100 times, the organic extracts enriched from the water samples showed some positive reactions. The micronuclear rates of root-tip cells were of significantly difference between all groups (F = 42.526, P < 0.001). Compared with each other, the group of DMSO and the group of new technique were not significantly different from the negative control (P > 0.05), but the group of secondary effluent and the group of influent were significantly different from the new technique (P < 0.05), at last, there was significant difference between the secondary effluent and the influent (P < 0.05). After exposed with DMSO and the organic extracts, the length of comet tails and the tailing ratio were obviously different between all groups (F = 243.535 and 148.623 correspodingly, P < 0.001). Compared with negative control, the length of comet tails and the tailing ratio of the influent group and the secondary effluent group were significantly different (P < 0.01). Compared with the influent group, the comet tail length of the secondary effluent group and the tertiary effluent group were both shorter (P < 0.01), and the tailing ratio were both smaller (P < 0.01). The tailing ratio of the tertiary effluent group was significantly smaller than the secondary effluent group. CONCLUSION: The inherent toxicity of urban sewage in Zhengzhou was significantly decreased after treated but it still possesses potential hazard to environment. And the trace organic pollutants in wastewater were removed by the new technique more efficiently than by the present treatment.

Estrogenic activity of organic extracts in the effluents treated byivity present treatment and the new process.

OBJECTIVE: Evaluate the estrogenic activity of organic extracts in the effluents treated by present treatment and the new technique find the scientific evidences of the new wastewater treatment technique to compare the removal efficiency of trace organic pollutants. METHODS: The solid phase extraction was adopted to enrich the trace organic pollutants in the water samples with resin adsorbing, then detected the estrogenic activity of them by using yeast estrogens screen and immature rat uterine bioassay. RESULTS: Yeast estrogens screen demonstrated that the organic extracts in the new technique effluent showed the activity as estrogen after concentrated 1000 times, because the activity of beta-galactosidase produced by yeast began to appear, otherwise, the same phenomenon occurred for the tertiary effluent, the secondary effluent and the influent at concentration of 500 times. At same concentration times of the extracts, the activity of beta-galactosidase of each group could be listed as, the new technique effluent < the tertiarity effluent < the secondary effluent < the influent. The immature rat uterine bioassay showed there was significant difference only between the high dose group of the influent organic extracts and the negative control (P < 0.05), but not between other groups, about the ratio of uterine weight to body weight. CONCLUSION: The estrogenic activity of urban sewage in Zhengzhou was significantly decreased after treated but it still possesses potential hazard to environment. And the trace organic pollutants in wastewater were removed by the new technique more efficiently than by the present treatment.

[Toxicity evaluation on the effluent water from a sewage treatment plant in Zhengzhou City].

OBJECTIVE: To explore the acute toxicity and genotoxicity of inlet and outlet water of a sewage treatment plant in Zhengzhou to provide scientific basis for the safety of sewage reuse. METHODS: Inlet water, secondary and tertiary processed outlet water were collected from the sewage treatment plant. Acute toxicity and genotoxicity of the inlet and outlet water were detected by luminescent bacteria toxicity test and Vicia faba root tip cell micronucleus test, respectively. RESULTS: The luminosity inhibition rates of luminescent bacteria by inlet water, secondary and tertiary processed outlet water were (33.96 +/- 7.51)%, (14.32 +/- 7.36)% and (7.24 +/- 5.58)%, and the micronucleus rates were (12.67 +/- 2.08) per thousand, (6.33 +/- 1.53) per thousand and (2.67 +/- 0.58) per thousand, respectively. The pollution levels of these three samples were heavy, mild and scarce, respectively. The inhibition rates of luminescent bacteria by the secondary and tertiary processed water were significantly lower than that of inlet water (F = 12.159, P = 0.008). A similar result was observed for micronucleus rate (F = 56.850, P < 0.001). CONCLUSION: The acute toxicity and genotoxicity of processed water were decreased greatly. However, some potential ecological risks of the processed water still existed for environment.

Assessing estrogenic activity and reproductive toxicity of organic extracts in WWTP effluents.

Trace level organic contaminants might not be completely removed from the municipal wastewater and the safety incurred by them had become a concern. These organic pollutants were extracted from water samples and detected by GC-MS. The estrogenic activity of the organic was tested using Yeast Estrogen Screen to detect the transcriptional activation of the estrogen receptor (ER) and immature mouse uterotrophic bioassays to study reproductive toxicity. The results of GC-MS demonstrated the organic extracts in the municipal wastewater and the WWTP effluents Included two major categories, benzenes and Phthalates. The estrogenic activity of organic extracts from the secondary effluent (SE) and tertiary effluent (TE) was below that of the raw wastewater (RW). Results of uterotrophic bioassay demonstrated that SE would bring some potential hazards on animals while TE was relatively safe.

[Pilot validation of sludge concentration partition at small reflux ratio condition].

Using sub-milliFiltration (SMF) module get the sludge of the system divide into high concentration part and low concentration part, in order to make the high concentration part retain activated sludge to strengthen removal rate of organics and the low concentration part meet the need of MBR. Discussing the sludge concentration partition effect under the conditions of small reflux ratio(R 0.5, 1.0, 1.5, 2.0), In addition, investigating the COD removal efficiency of the system with SMF Module, comparing the measured and theoretical value of the MLVSS at each small reflux ratio. Results show that: the method of sludge concentration partition at small reflux ratio condition is feasible, the MLSS of the low concentration part is below 9 g x L(-1) and the high concentration part is above 20 g x L(-1); average removal rate of COD is above 90%; measured value of the two part is related to theoretical value.