Distribution of tetraether lipids in sulfide chimneys at the Deyin hydrothermal field, southern Mid-Atlantic Ridge: Implication to chimney growing stage.

This study presents analysis of four chimney samples in terms of glycerol dialkyl glycerol tetraether lipids (GDGTs), representing different growing stages of sulfide chimneys at the Deyin hydrothermal field, the southern mid-Atlantic ridge. The modified Bligh-Dyer method was used for lipid extraction and purification. GDGTs were analyzed with an Agilent 1200 series liquid chromatograph and 6460A triple quadrupole mass spectrometer. Our results showed that the intact polar GDGTs were more abundant than the core GDGTs in the 4 samples. The intact polar isoprenoidal GDGT-0 was the dominant composition (>70% of isoprenoidal GDGTs), indicating input of thermophilic Euryarchaeota. Most branched GDGTs were likely originated from the in situ thermophilic bacteria. However, the intact polar GDGTs in the sample at the late growing stage was similar to that in normal marine sediments, suggesting that the archaea mainly came from the planktonic Thaumarchaeota input. Our results suggested that the ratio of H-GDGTs to iGDGTs could be considered as a proxy to differentiated growing stages of a chimney. This study shed light on how to assess hydrothermal venting and sulfide chimneys in deep marine environments with a biomarker method in terms of different groups of GDGTs.

Ammonia removal from leachate solution using natural Chinese clinoptilolite.

This paper assesses the potential of natural Chinese clinoptilolite for ammonia removal from the leachate solution of sewage sludge. In batch study the effects of relevant parameters, such as contact time, initial ammonia concentration and particle size of clinoptilolite, were examined respectively. The results show that the data obtained from batch studies were fit to Langmuir and Freundlich isotherms and the Langmuir isotherms reflect more reasonable for ammonium ion uptake onto clinoptilolite; the clinoptilolite adsorption process has been proved effective, at laboratory scale, the maximum adsorption capacity of the clinoptilolite, for ammonium concentration ranging from 11.12 to 115.16 mg NH(4)-N L(-1) in leachate solution, was about 1.74 mg NH(4)-Ng(-1); the time to adsorption equilibrium was 2.5 h in leachate solution and 1.5 h more than for in NH(4)Cl synthetic solution; ammonium adsorption increased with decreasing clinoptilolite particle size; the ammonia removal capacity of clinoptilolite increased with increasing initial ammonia concentration. It is believed that as adsorption agent for NH(4)-N removal from sludge leachate, natural Chinese clinoptilolite can be feasible.

Optimization of phosphorus removal from secondary effluent using simplex method in Tianjin, China.

Enhanced concentrations of phosphorus entering the aquatic systems have been linked with eutrophication and its associated problems. Jar tests were applied to a secondary effluent in order to determine optimal conditions for coagulation. The coagulants studied were ferric sulfate [Fe2(SO4)3], aluminum sulfate [Al2(SO4)3.18H2O] and polyaluminum chloride (PAC). The experiments were carried out using simplex research technique to determine the optimum conditions of these coagulants for phosphorus removal. For each coagulant examined, 18-25 experiments were carried out until a maximum removal was observed through the experimental procession. Increases of greater than 30% were found for the removal efficiencies of these three coagulants over the course of the experiments. Good removal efficiencies averaging at least 87.25% were obtained through the simplex procession. The orthophosphate removal efficiency was higher than that of total phosphorus for each coagulant. The maximum removal efficiency of total phosphorus obtained from the optimization procedures for ferric sulfate, aluminum sulfate and polyaluminum chloride was 87.3, 95.6 and 94.0%, respectively, and the minimum total phosphorus residual was 0.35, 0.12 and 0.16 mg/L, respectively.