Analysis of water quality factors influencing the speciation of inorganic nitrogen using GRA.

Based on the water quality data from 2006 to 2008, grey relational analysis (GRA) is used to analyze factors that may have influence on the speciation of inorganic nitrogen in the Chengdu section of middle Min river. The results show that water temperature, changing from 20.2 +/- 2.7, 13.4 +/- 5.7 and 16.8 +/- 5.6 degrees C, is the first restrictive factor for the speciation of inorganic nitrogen; it is negatively correlated with the ratio of total ammonia nitrogen to total inorganic nitrogen contents [m(AN)/m(TIN)] in three different periods of wet season, dry season and year-round. The average pH values for years, in wet and dry periods are 7.6 +/- 0.4, 7.3 +/- 0.3 and 7.8 +/- 0.2, respectively, and have different influences in different seasons. It is the second restrictive factor and positive correlation between pH and m(AN)/m(TIN) in wet season and through the year yet it is the fourth factor in dry seasons. The values of dissolved oxygen (DO), which are 4.6 +/- 1.4, 4.6 +/- 2.4, 4.6 +/- 2.0 respectively, is the third factor and negatively correlates with m(AN)/m(TIN) in third different periods. The chemical oxygen demand (COD) indirectly inhibits the nitrifying bacteria because the DO is depleted in the decomposition of organic matter by heterotrophic bacteria, showing the positive correlation.As the alkalinity can meet the requirement of nitrification in wet season and through the year, it is not restrictive factor. However, it is the second restrictive factor in dry season because of low content of alkalinity inhibiting the growth of nitrifying bacteria.

[Survey of self-rated health status of troop members stationing in the South China Sea islands].

OBJECTIVE: To conduct a survey of the self-rated health status of the troops stationing in the islands of the South China Sea. METHODS: Altogether 290 members of the selected troops were investigated by means of self-rated health evaluation sale (SRHMS 1.0), and the factors affecting the health status were analyzed. RESULTS: No significant difference was noted in the physical and psychosocial health between the troops in the isolated islands, but the social health and self-rated health significantly differed (P<0.05). The individual identity, dwelling place or education background did not significantly affect self-rated health status as the marital status did (P<0.05). CONCLUSIONS: The self-rated health of the troop members differ to some degree, especially the social health condition, and is affected by marital status in stead of the individual identity, dwelling place, and education background.

Presence of Fe3+ and Zn2+ promoted biotransformation of Cd-citrate complex and removal of metals from solutions.

The promotion to Cd-citrate complex biotransformation via addition of Fe(3+) and Zn(2+) was investigated. Single Fe(III)- or Zn-citrate complex was completely degraded by Pseudomonas sp. MBR, Cd-citrate complex was not. In the Cd-citrate media with molar ratio of 1:2 and 1:3, pH increase obtained from the metabolism of excess citrate slightly promoted the biotransformation of Cd-citrate complex, Cd remained in solutions. The presence of Fe(3+) and Zn(2+) resulted in complete biotransformation of Cd-citrate complex in the 1:1:2 Fe:Cd:citrate and Zn:Cd:citrate and 1:1:1:3 Fe:Zn:Cd:citrate media. Alkaline pH obtained from biotransformation of metal-citrate complexes caused almost complete removal of metals (>98%) through precipitation and co-precipitation. Pseudomonas sp. MBR potentially could be used to treat wastewater containing mixed citrate complexes of Fe(III), Zn and Cd.

[Study on biodegradation of polyacrylamide].

Phanerochaete chrysosporium was introduced into biodegradation of polyacrylamide(PAM), and effects of glucose amount, pH, N concentration, Mn2+ concentration and biodegradation time on biodegradation of PAM were studied. Results show that Phanerochaete chrysosporium has special abilities of enzyme catalysis biodegradation of PAM. And the removal rate of PAM is 50%. Nitrogen limitation (NH4+ = 0.2 g/L) and Mn2+ concentration (Mn2+ = 0.017 5 g/L) are optima of producing PAM biodegradation enzyme.

[Pilot test on oil field wastewater biotreatment with thermophilic microorganisms].

The thermophilic microorganisms (50-60 degrees C) are introduced and the contact oxidation technology is adopted to treat with the high temperature effluents from an oil field in this paper, which solves a problem that the effluents need to be cooled in routine biotreatment. The results of the pilot test show that the HRT of the biotreatment system adjusted to 8-18h can make CODCr of the effluents stable at 175-263mg/L and oil content under 10mg/L on condition that the temperature of the influents keeps at 60-65 degrees C, CODCr 300-590mg/L and the quality of the oil wastewater is greatly fluctuant. Flocculating process, then, can effectively flocculate and precipitate the suspending and residual chroma pollutant from the effluents of biotreatment and CODCr in the effluents of flocculating process can reduce to 136-229mg/L. And CODCr even reduces to under 150mg/L after flowing by sand and activated carbon filtration equipments. Under the high temperature condition, furthermore, combined stuffing is an ideal carrier for the thermophilic microorganisms.