Simultaneous nitrification and denitrification with anoxic phosphorus uptake in a membrane bioreactor system.

The performance of an innovative membrane bioreactor (MBR) process using anoxic phosphorus uptake with nitrification and denitrification for the treatment of municipal wastewater with respect to operational performance and effluent quality is addressed in this paper. The system was operated at steady-state conditions with a synthetic acetate-based wastewater at a hydraulic retention time (HRT) of 12 hours and on degritted municipal wastewater at a total system HRT of 6 hours. The MBR system was able to achieve 99% biochemical oxygen demand (BOD), chemical oxygen demand (COD), and ammonia-nitrogen (NH4(+)-N); 98% total Kjeldahl nitrogen (TKN); and 97% phosphorus removal, producing effluent BOD, COD, NH4+-N, TKN, nitrate-nitrogen, nitrite-nitrogen, and phosphate-phosphorus of <3, 14, 0.2, 0.26, 5.8, 0.21, and <0.01 mg/L, respectively, at the 6-hour HRT. The comparison of the synthetic and municipal wastewater run is presented in this paper. Steady-state mass balance on municipal wastewater was performed to reveal some key features of the modified MBR system.     

Photochemistry of 1-nitro-2-phenylnaphthalene available to the environment

Photolysis (254 nm, 72h) of 1-nitro-2-phenylnaphthalene $\text{1}$ in methanol gave 2-phenyl-1,4-naphthoquinone-4-monoxime $\text{2}$, 2,2′-diphenyl-4,4′-binaphth-1,1′-diol $\text{3}$ and 2,2′-diphenyl-4,4′-binaphth-1,1′-dione $\text{4}$. Straightforward reactions available to the environment account for the formation of the products: (a) isomerisation of the nitro compound into a nitrite ester followed by either (a) migration of the nitroso group and isomerisation into the oxime $\text{2}$ or (b) oxidative coupling and solvolysis into the binaphthol $\text{3}$ and followed by oxidation into the binaphthone $\text{4}$.     

Short-term Emissions of Ammonia and Carbon Dioxide from Cattle Urine Contaminated Tropical Grassland Microcosm

The study was designed to understand the emissions of ammonia (NH₃) and carbon dioxide (CO₂) from a single cattle urination event on a tropical grassland and underline the significance of the emissions in the context of huge animal population grazing on large pasture areas in some countries. Emissions of ammonia (NH₃) and carbon dioxide (CO₂) were monitored for three weeks from a tropical grassland (dominated by Cynodon dactylon Pers.) microcosm contaminated with cow and buffalo urine. The grassland microcosms were treated with urine (50 and 100 ml of each) only once and irrigated with water once every week. Ammonia was sampled by an automatic sampling system comprising of a vacuum pump, three-way stopcocks and rubber tubing and an impinger containing suitable absorbing solution (H₂SO₄), connected to the tubing suitably. The sampled gas, after sucked by the vacuum pump and absorbed in H₂SO₄, was allowed to enter the closed microcosm again maintaining internal pressure of the microcosm. Carbon dioxide was sampled by absorption in an alkali (NaOH) trap inside the microcosm. Both NH₃ and CO₂ emissions were highly variable temporally and there was no continuous increasing or decreasing emission trend with time. Respectively, 45 and 46% of total NH₃-N were emitted within first 48 h from 50 and 100 ml cow urine application while the corresponding values for buffalo urine were 34 and 32%. Total NH₃-N emissions, integrated for sampling days (i.e. 1, 2, 3, 4, 6, 15, 18 and 21st) were 11 and 6% in cow and 8 and 5% in buffalo urine, of the total-N added through 50 and 100 ml urine samples. Carbon dioxide emissions were standardized at 25 ^∘C by using a suitable formula which were lower than actual emissions at actual soil temperature (> 25 ^∘C). Carbon dioxide emission rates were classified on the basis of soil repiratory classification and classes ranged from moderately low soil activity up to unusually high soil activity, the latter observed only on very few sampling days. Grasses in the microcosm had shown appreciable growth after urine application. Although variable and somewhat unpredictable, emissions were appreciable and that too only from a patch of single urination, indicating to the huge magnitude of total emissions under the scenario of thousands of cattle grazing on hundreds of acres of grasslands in a tropical country.     

Design Variables Associated with Fiberglass/Fly Ash Fabric Filter Cleaning

This paper documents the variation in pressure drop and collection efficiency for fiberglass/fly ash fabric filter systems caused by variations in cleaning intensity (reverse air and reverse pulse), air to cloth ratio, and dust loading. Reverse air rates greater than 2 fpm were required to produce stable pressure characteristics. Pulse jet pressure greater than 50 psi reduced collection efficiency. Increased air to cloth ratios produced decreased collection efficiency.     

Estimation and analysis of terrestrial net primary productivity over India by remote-sensing-driven terrestrial biosphere model

Concentrations of cadmium, copper, and lead were determined in surficial sediments and the soft tissues (foot and gills) of swan mussel Anodonta cygnea from two sampling sites in Anzali wetland, which is an internationally important wetland registered in the Ramsar Convention. The metal contents in the mussel species from the studied region were comparable to other world areas. In most cases, the levels of the metals either fell within the range for other areas or were lower. There were significant differences between the tissues for the accumulation of Cd and Pb. Only in the case of Pb accumulation in gills significant differences between the specimens from the selected sampling sites could be observed. Age-related correlations were found in the case of Cu accumulation in foot and Cd levels in gills. No weight-dependent trend could be observed for the accumulation of the three elements. There was significant negative width-dependent relationship in the case of Cu. A significant negative correlation was also found between the maximum shell height and Cu accumulation in the gills. The only association among the elements in the selected soft tissues was found between Cd and Pb. Highly significant differences could be found between the sampling sites from the concentration of the elements in sediments point of view. The pattern of metal occurrence in the selected tissues and sediments exhibited the following descending order: Pb, Cu>Cd for gills, Cu>Pb, Cd for foot, and Cu>Pb>Cd for sediments. The mean concentrations of Cd and Pb in the sediments from the study area were higher than the global baseline values and world average shale. In the case of Cu, our results were somewhat higher than the baseline values but well below the world average shale.     

Biological monitoring of chlorpyrifos exposure to rice farmers in Vietnam

Chlorpyrifos is the most common organophosphate insecticide registered for use in Vietnam and is widely used in agriculture, particularly rice farming. However, chlorpyrifos exposure to and adverse effects on farmers has not been evaluated. In this study, biological monitoring of chlorpyrifos exposure in a group of rice farmers was conducted after a typical application event using back-pack spraying.Urine samples (24 h) were collected from the rice farmers before and post insecticide application. Samples were analysed for 3,5,6-trichloropyridinol (TCP), the major urinary metabolite of chlorpyrifos, using an enzymatic pre-treatment before extraction followed by HPLC-MS/MS. Absorbed Daily Dose (ADD) of chlorpyrifos for farmers were then estimated from urinary TCP levels, expressed as μg g⁻¹ creatinine. The analytical method for urinary TCP had a low detection limit (0.6 μg L⁻¹), acceptable recovery values (80-114%), and low relative percentage differences in duplicate and repeated samples.Post-application chlorpyrifos ADD of farmers varied from 0.4 to 94.2 μg kg⁻¹ (body weight) d⁻¹ with a mean of 19.4 μg kg⁻¹ d⁻¹ which was approximately 80-fold higher than the mean baseline exposure level (0.24 μg kg⁻¹ d⁻¹). Hazard Quotients (ratio of the mean ADD for rice farmers to acute oral reference dose) calculated using acute oral reference doses recommended by United States and Australian agencies varied from 2.1 (Australian NRA), 4.2 (US EPA) to 6.9 (ATSDR).Biological monitoring using HPLC-MS/MS analysis of urinary TCP (24 h) was found to be an effective method for measuring chlorpyrifos exposure among farmers. This case study found that Vietnamese rice farmers had relatively high exposures to chlorpyrifos after application, which were likely to have adverse health effects.     

Techno-economic performance analysis and environmental impact assessment of small to medium scale SRF combustion plants for energy production in the UK

This paper investigates a techno-economic analysis on small and medium scales: 50 kilo tonnes per annum (ktpa) and 100 ktpa combustion plants with steam turbine technology utilising solid recovered fuel (SRF). Energy and efficiency calculations for the technical assessment are performed. The economic viability of the two processes is investigated through a discounted cash flow analysis. The levelised cost is used to calculate the cost of production of one unit of electricity. A life cycle assessment (LCA) of the 100 ktpa scale SRF plant is performed, where the foundations of LCA calculations reside in energy calculations carried out for the technical analysis. Life cycle inventories were developed using inventory analysis and impact assessment. The results of the LCA are compared with those from equivalent scale coal, natural gas and electricity-mix plants. The LCA is also compared with a landfill reference system. Both scales are economically and technically viable. The SRF plant has a lower global warming potential emission (E_GWP) compared with the coal, natural gas and electricity-mix plants and the reference landfill system.     

Analysis of agricultural drought using vegetation temperature condition index (VTCI) from Terra/MODIS satellite data

The most commonly used normalized difference vegetation index (NDVI) from remote sensing often fall short in real-time drought monitoring due to a lagged vegetation response to drought. Therefore, research recently emphasized on the use of combination of surface temperature and NDVI which provides vegetation and moisture conditions simultaneously. Since drought stress effects on agriculture are closely linked to actual evapotranspiration, we used a vegetation temperature condition index (VTCI) which is more closely related to crop water status and holds a key place in real-time drought monitoring and assessment. In this study, NDVI and land surface temperature (T _s) from MODIS 8-day composite data during cloud-free period (September–October) were adopted to construct an NDVI–T _s space, from which the VTCI was computed. The crop moisture index (based on estimates of potential evapotranspiration and soil moisture depletion) was calculated to represent soil moisture stress on weekly basis for 20 weather monitoring stations. Correlation and regression analysis were attempted to relate VTCI with crop moisture status and crop performance. VTCI was found to accurately access the degree and spatial extent of drought stress in all years (2000, 2002, and 2004). The temporal variation of VTCI also provides drought pattern changes over space and time. Results showed significant and positive relations between CMI (crop moisture index) and VTCI observed particularly during prominent drought periods which proved VTCI as an ideal index to monitor terminal drought at regional scale. VTCI had significant positive relationship with yield but weakly related to crop anomalies. Duration of terminal drought stress derived from VTCI has a significant negative relationship with yields of major grain and oilseeds crops, particularly, groundnut.     

Fluoride Deposition in Central India

Fluoride is a volatile element emitted from natural and anthropogenic sources into the atmoshere and scavenged from the atmosphere by rain water. We collected 444 rain water and 36 dust samples on an event basis at 13 sites and on the bulk basis (monthly) at 3 sites, respectively, in central India (extending over 17°N to 24°N latitude and 80° 17 to 84°11E longitude). The level of F- in the atmospheric samples was determined by automating the conventional Zr(IV)-SPADNS [Sodium 2- (parasulfophenylazo)-1, 8-dihydroxy-3, 6-naphthalene disulfonate] method in the presence of surfactant, i.e. TX–100 [Triton x- 100]. The detection limit of the method is 10.0 ppb F- with a sample throughput of 70 samples/h. The F- deposited with rain water (in 13 sites) and with dust (three sites) were ranged between 54.8 to 483.0, and 105.0 to 503.3 kg/km2/year, respectively. The level of F- in atmospheric samples, seasonal and spatial variation in deposition and sources of F- are discussed.