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Mg NO3 (mg + no3)
Selected AbstractsThe solute budget of a forest catchment and solute fluxes within a Pinus radiata and a secondary native forest site, southern ChileHYDROLOGICAL PROCESSES, Issue 13 2002Geertrui Y. P. Uyttendaele Abstract Solute concentrations and fluxes in rainfall, throughfall and stemflow in two forest types, and stream flow in a 90 ha catchment in southern Chile (39°44,S, 73°10,W) were measured. Bulk precipitation pH was 6·1 and conductivity was low. Cation concentrations in rainfall were low (0·58 mg Ca2+ l,1, 0·13 mg K+ l,1, 0·11 mg Mg2+ l,1 and <0·08 mg NH4,N l,1), except for sodium (1·10 mg l,1). Unexpected high levels of nitrate deposition in rainfall (mean concentration 0·38 mg NO3,N l,1, total flux 6·3 kg NO3,N ha,1) were measured. Concentrations of soluble phosphorous in bulk precipitation and stream flow were below detection limits (<0·09 mg l,1) for all events. Stream-flow pH was 6·3 and conductivity was 28·3 ,s. Stream-water chemistry was also dominated by sodium (2·70 mg l,1) followed by Ca, Mg and K (1·31, 0·70 and 0·36 mg l,1). The solute budget indicated a net loss of 3·8 kg Na+ ha,1 year,1, 5·4 kg Mg2+ ha,1 year,1, 1·5 kg Ca2+ ha,1 year,1 and 0·9 kg K+ ha,1 year,1, while 4·9 kg NO3,N ha,1 year,1 was retained by the ecosystem. Stream water is not suitable for domestic use owing to high manganese and, especially, iron concentrations. Throughfall and stemflow chemistry at a pine stand (Pinus radiata D. Don) and a native forest site (Siempreverde type), both located within the catchment, were compared. Nitrate fluxes within both forest sites were similar (1·3 kg NO3,N ha,1 year,1 as throughfall). Cation fluxes in net rainfall (throughfall plus stemflow) at the pine stand generally were higher (34·8 kg Na+ ha,1 year,1, 21·5 kg K+ ha,1 year,1, 5·1 kg Mg2+ ha,1 year,1) compared with the secondary native forest site (24·7 kg Na+ ha,1 year,1, 18·9 kg K+ ha,1 year,1 and 4·4 kg Mg2+ ha,1 year,1). However, calcium deposition beneath the native forest stand was higher (15·9 kg Ca2+ ha,1 year,1) compared with the pine stand (12·6 kg Ca2+ ha,1 year,1). Copyright © 2002 John Wiley & Sons, Ltd. [source] A hollow fiber membrane photo-bioreactor for CO2 sequestration from combustion gas coupled with wastewater treatment: a process engineering approachJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2010Amit Kumar Abstract BACKGROUND: In the presence of light, micro-algae convert CO2 and nutrients to biomass that can be used as a biofuel. In closed photo-bioreactors, however, light and CO2 availability often limit algae production and can be difficult to control using traditional diffuser systems. In this research, a hollow fiber membrane photo-bioreactor (HFMPB) was investigated to: (1) increase the interfacial contact area available for gas transfer, (2) treat high nutrient strength (412 mg NO3, -N L,1) wastewater, and (3) produce algal biomass that can be used as a biofuel. RESULTS: A bench scale HFMPB was inoculated with Spirulina platensis and operated with a 2-15% CO2 supply. A mass transfer model was developed and found to be a good tool to estimate CO2 mass transfer coefficients at varying liquid velocities. Overall mass transfer coefficients were 1.8 × 10,6, 2.8 × 10,6, 5.6 × 10,6m s,1 at Reynolds numbers of 38, 63, and 138, respectively. A maximum CO2 removal efficiency of 85% was observed at an inlet CO2 concentration of 2% and a gas residence time (membrane-lumen) of 8.6 s. The corresponding algal biomass concentrations and NO3 removal efficiencies were 2131 mg L,1 and 68%, respectively. CONCLUSION: The results show that the combination of CO2 sequestration, wastewater treatment and biofuel production in an HFMPB is a promising alternative for greenhouse gas mitigation. Copyright © 2010 Society of Chemical Industry [source] The effects of irrigation, nitrogen fertilizer and grain size on Hagberg falling number, specific weight and blackpoint of winter wheatJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2004Matthew P Clarke Abstract The effects of irrigation and nitrogen (N) fertilizer on Hagberg falling number (HFN), specific weight (SW) and blackpoint (BP) of winter wheat (Triticum aestivum L) were investigated. Mains water (+50 and +100 mm month,1, containing 44 mg NO3, litre,1 and 28 mg SO42, litre,1) was applied with trickle irrigation during winter (17 January,17 March), spring (21 March,20 May) or summer (24 May,23 July). In 1999/2000 these treatments were factorially combined with three N levels (0, 200, 400 kg N ha,1), applied to cv Hereward. In 2000/01 the 400 kg N ha,1 treatment was replaced with cv Malacca given 200 kg N ha,1. Irrigation increased grain yield, mostly by increasing grain numbers when applied in winter and spring, and by increasing mean grain weight when applied in summer. Nitrogen increased grain numbers and SW, and reduced BP in both years. Nitrogen increased HFN in 1999/2000 and reduced HFN in 2000/01. Effects of irrigation on HFN, SW and BP were smaller and inconsistent over year and nitrogen level. Irrigation interacted with N on mean grain weight: negatively for winter and spring irrigation, and positively for summer irrigation. Ten variables derived from digital image analysis of harvested grain were included with mean grain weight in a principal components analysis. The first principal component (,size') was negatively related to HFN (in two years) and BP (one year), and positively related to SW (two years). Treatment effects on dimensions of harvested grain could not explain all of the effects on HFN, BP and SW but the results were consistent with the hypothesis that water and nutrient availability, even when they were affected early in the season, could influence final grain quality if they influenced grain numbers and size. Copyright © 2004 Society of Chemical Industry [source] Investigating the in situ degradation of atrazine in groundwater,PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 4 2006Robert Pearson Abstract This study focused on whether or not atrazine could be degraded by indigenous groundwater bacteria as part of an in situ remediation approach. Groundwater was taken from an unconfined middle upper chalk site where concentrations of atrazine and nitrate were typically in the ranges 0.02,0.2 µg litre,1 and 11.6,25.1 mg NO3 -N litre,1 respectively. Sacrificial batch studies were performed using this groundwater spiked with atrazine at a concentration of 10 µg litre,1 in conjunction with a minimal mineral salts liquid (Glu-MMSL) medium which contained glucose as the sole carbon source. Treatments comprised either the Glu-MMSL groundwater cultured bacteria or Pseudomonas sp. strain ADP. Results from sacrificial batches indicated the occurrence of bacterial growth and denitrification as monitored by optical density (absorbance at 600 nm) and NO3 -N content. Analysis of atrazine content by solid phase extraction coupled with high-performance liquid chromatography showed no degradation of atrazine over a period of 103 days in either treatment. These results indicated that no acclimatised bacterial community featuring positive degraders to the herbicide atrazine had become established within this chalk aquifer in response to the trace levels encountered. Copyright © 2006 Society of Chemical Industry [source] Development of a procedure for sustainable in situ aquifer denitrificationREMEDIATION, Issue 2 2003Imtiyaz A. Khan Denitrification experiments have provided data showing the pitfalls and successes in developing a sustainable injection/extraction system in a sand and gravel aquifer. Experiments increase in complexity from continuous injection at one well to automated-pulsed eight well injections. In both continuous and pulsed injection of organic carbon, 40 mg NO3- N l,1 was reduced below the detection limit of < 0.1 mg NO3- N l,1 in the denitrification zones. Under continuous injection, accumulation of bacterial exudates in the vicinity of the injection well resulted in injection well clogging within ten days. Periodic cleaning of the injection well and the adjacent gravel matrix was accomplished by using a tool developed to circulate a cleaning solution composed of 5 percent H2O2 and 0.02 percent NaOCl; but, biofouling could not be eliminated. In the later experiments, acetate became the carbon amendment because ethanol promoted more biomass development. A specialized pulse injection procedure was developed to separate nitrate from acetate-C and was successful in alleviating the proliferation of bacterial exudates without affecting the performance of the denitrification system. Using pulsed injection, a maximum of 72 percent nitrate reduction was accomplished in the extraction well water, and denitrification was sustained for three months without clogging. © 2003 Wiley Periodicals, Inc. [source] | ||||||||||