Process modification in the scouring process of textile industry

The effects of scouring parameters on the scouring efficiency, including the weight ratio of de-sizing agent and fabric (5–80 g/g fabric), temperature of de-sizing agent tank (60–90 °C) and dipping time (2–8 s), were investigated. The results demonstrated that weight loss of sizing agent was significantly observed only in the de-sizing agent tank particularly in the first de-sizing tank and was found to a small extent in water tank. The optimum condition in the scouring machine was found at a de-sizing agent to fabric ratio of 20 g/g fabric, with a temperature of the first de-sizing agent tank of 80 °C, a temperature of the second de-sizing agent tank of 90 °C, and dipping time of fabric of 7 s. According to these conditions, more than 89% of the sizing agent was eliminated and only 3.52 mg/g fabric of sizing agent remained in the scoured fabric which was in an acceptable range for feeding to the down stream process known as dyeing process. Application of our results to actual textile plant has shown that there is a cost reduction due to improved utilization of rinse water, chemicals and energy in the process and consequent decreases in the generation of wastewater. Furthermore, the production capacity was increased from 30 m/min to 34.4 m/min.     

Micelle dyeing with low liquor ratio for reactive dyes using dialkyl maleic acid ester surfactants

Micelle dyeing with low liquor ratio is novel fabric dyeing method for cleaner production. Preparation and interaction of dye-surfactant micelles using dibutyl maleic acid ester sodium sulfate surfactant were investigated by UV-Vis spectra. Dyeing properties of cellulose fabrics using micelle dyeing with low liquor ratio were discussed by color yields (K/S), color differences (ΔE), exhaustion (E), fixation (F) and reactivity (R) of three reactive dyes. The results show that reactive dye molecules could be solved in surfactant micelles and form stable dye-surfactant micelles. Micelles formed by dibutyl maleic acid ester sodium sulfate had good anti-agglomeration effect on dye solutions. Liquor ratio of micelle dyeing for cellulose fabrics could be reduced from 1:15 to 1:5. Leveling properties of three reactive dyes using micelle dyeing were good. The exhaustion, fixation and reactivity of all three dyes using micelle dyeing were similar with the conventional dyeing technology. Wet rubbing, washing and perspiration fastnesses of dyed samples using micelle dyeing were also good. Micelle dyeing with low liquor ratio can save a large amount of water and energy.     

Reuse of printing and dyeing wastewater in processess assessed by pilot-scale test using combined biological process and sub-filter technology

In this work, a pilot-scale (300 m³/d) wastewater reclamation system was tested for printing and dyeing wastewater treatment from a textile factory. The wastewater was first hydrolyzed under anoxic condition, and then was treated under aerobic condition. Biologically treated wastewater was filtered by sub-filter technology (Patent: CN1308024A). The results showed that the average concentration of CODcr, color and turbidity in the effluent were less than 50 mg/L, 10 times and 2 NTU, respectively. The average CODcr, color and turbidity removal efficiencies were 91%, 92.5% and 90.9%, respectively. The treated effluent quality satisfied the requirement of water quality for printing and dyeing process. The most attracting part of the work was its extremely low color, low turbidity, low concentration of Fe and Mn, which was always demanded in textile sectors for an improved finish and better quality dyeing.     

Application of power ultrasound in leather processing: an eco-friendly approach

The paper analyses and reviews in detail the use of ultrasound as a tool to improve the cleanliness of leather production for each stage of leather processing, showing that ultrasound has the added advantages of improving the process efficiency, reducing the process time and improving the quality of leather produced. The rate of diffusion of chemicals such as dyes through the pores of the leather matrix can be enhanced by the use of power ultrasound. Thus the optimum amount of chemicals required can be employed to improve the % exhaustion of chemicals, thereby minimising the significant amount of unspent chemicals in the effluent and reducing pollution load to a large extent. Dyeing experiments carried out in the presence of ultrasound (150 W and 33 kHz) give an increase of about 40% in dye exhaustion and a decrease in dyeing time by about 55% compared with the process in the absence of ultrasound under stationary conditions. Compared with conventional drumming conditions, ultrasound increases dye exhaustion by about 28% and reduces dyeing time by 25%. Ultrasound can also function as a physical activator and reduce the use of conventional chemicals in some of the processing stages, such as soaking for cleaning the raw skin/hide, liming for loosening hair and degreasing for removing natural fat. Therefore, ultrasound can be employed effectively in leather processing to enjoy multifaceted benefits.     

Biological hydrogen production by Rhodobacter capsulatus in solar tubular photo bioreactor

The purpose of this study was to develop a pilot scale tubular photo bioreactor (80 L) for photo fermentative hydrogen production by photosynthetic purple-non-sulfur bacterium, Rhodobacter capsulatus, operating in outdoor conditions, using acetate as the carbon source. The reactor was operated continuously in fed-batch mode for 30 days throughout December 2008 in Ankara. It was placed in a greenhouse in order to keep the temperature above freezing levels. It was found that R. capsulatus had a rapid growth with a specific growth rate of 0.025 h^?1 in the exponential phase. The growth was defined with modified logistic model for long term duration. The hydrogen production and feeding started in the late exponential phase. Evolved gas contained 99% hydrogen and 1% carbon dioxide by volume. The average molar productivity calculated during daylight hour was 0.31 mol H₂/(m³ h) with regard to the total reactor volume and 0.112 mol H₂/(m²·day) with regard to the total illuminated surface area. It was proven that even at low light intensities and low temperatures, the acetic acid which was fed to the system can be utilized for biosynthesis, growth and hydrogen production. The overall hydrogen yield was 0.6 mole H₂ per mole of acetic acid fed. This study showed that photofermentation in a pilot scale tubular photo bioreactor can produce hydrogen, even in winter conditions.     

Toward chemical-free reclamation of biologically pretreated greywater: solar photocatalytic oxidation with powdered activated carbon

Heterogeneous photocatalytic oxidation is a water reclamation technology which avoids chemical consumption and can be powered by solar radiation. Because this generally sustainable process is of limited efficiency for the treatment of biologically pretreated greywater, it was combined with activated carbon adsorption. The effluent of a constructed wetland for treatment of separately collected greywater was subjected to photocatalytic oxidation using the photocatalyst titanium dioxide (TiO₂) “P25” in both the absence and the presence of powdered activated carbon (PAC). Photocatalytic oxidation alone with UV fluences of about 10 Wh L^?1 was not capable of reducing total organic carbon (TOC) from an initial concentration of 5.5 mg L^?1 safely below 2 mg L^?1 as a prerequisite for high-quality water reuse purposes. However, when PAC was added, TOC concentrations subsequent to photocatalytic oxidation were less than 2 mg L^?1 even after reusing the TiO₂/PAC mixture 10 times. PAC addition is estimated to reduce the insolation area necessary to achieve this target by solar photocatalytic oxidation of biologically treated greywater by a factor 7. This combination process represents an innovative chemical-free technology within wastewater reuse schemes.     

Response of “Alamo” switchgrass tissue chemistry and biomass to nitrogen fertilization in West Tennessee,USA

Switchgrass (Panicum virgatum) is a perennial, warm-season grass that has been identified as a potential biofuel feedstock over a large part of North America. We examined above- and belowground responses to nitrogen fertilization in “Alamo” switchgrass grown in West Tennessee, USA. The fertilizer study included a spring and fall sampling of 5-year old switchgrass grown under annual applications of 0, 67, and 202 kg N ha^?1 (as ammonium nitrate). Fertilization changed switchgrass biomass allocation as indicated by root:shoot ratios. End-of-growing season root:shoot ratios (mean ± SE) declined significantly (P ≤ 0.05) at the highest fertilizer nitrogen treatment (2.16 ± 0.08, 2.02 ± 0.18, and 0.88 ± 0.14, respectively, at 0, 67, and 202 kg N ha^?1). Fertilization also significantly increased above- and belowground nitrogen concentrations and decreased plant C:N ratios. Data are presented for coarse live roots, fine live roots, coarse dead roots, fine dead roots, and rhizomes. At the end of the growing season, there was more carbon and nitrogen stored in belowground biomass than aboveground biomass. Fertilization impacted switchgrass tissue chemistry and biomass allocation in ways that potentially impact soil carbon cycle processes and soil carbon storage.     

Long-term impact of a gliricidia-maize intercropping system on carbon sequestration in southern Malawi

Tree/crop systems under agroforestry practice are capable of sequestering carbon (C) in the standing biomass and soil. Although studies have been conducted to understand soil organic C increases in some agroforestry technologies, little is known about C sequestered in simultaneous tree/crop intercropping systems. The main objective of this study was to determine the effect of agroforestry practice on C sequestration and CO₂-C efflux in a gliricidia-maize intercropping system. The experiment was conducted at an experimental site located at the Makoka Agricultural Research Station, in Malawi. The studies involved two field plots, 7-year (MZ21) and 10-year (MZ12), two production systems (sole-maize and gliricidia-maize simultaneous intercropping systems). A 7-year-old grass fallow (Grass-F) was also included. Gliricidia prunings were incorporated at each time of tree pruning in the gliricidia-maize. The amount of organic C recycled varied from 0.8 to 4.8 Mg C ha⁻¹ in gliricidia-maize and from 0.4 to 1.0 Mg C ha⁻¹ in sole-maize. In sole-maize, net decreases of soil carbon of 6 Mg C ha⁻¹ at MZ12 and 7 Mg C ha⁻¹ at MZ21 in the topsoil (0–20 cm) relative to the initial soil C were observed. After 10 years of continuous application of tree prunings C was sequestered in the topsoil (0–20 cm) in gliricidia-maize was 1.6 times more than in sole-maize. A total of 123–149 Mg C ha⁻¹ were sequestered in the soil (0–200 cm depth), through root turnover and pruning application in the gliricidia-maize system. Carbon dioxide evolution varied from 10 to 28 kg ha⁻¹ day⁻¹ in sole-maize and 23 to 83 kg ha⁻¹ day⁻¹ in gliricidia-maize. We concluded that gliricidia-maize intercropping system could sequester more C in the soil than sole-maize.     

Lodging in rice can be alleviated by atmospheric CO2 enrichment

The projected increase of atmospheric CO₂ concentration [CO₂] is expected to increase yield of agricultural C₃ crops, but little is known about effects of [CO₂] on lodging that can reduce yield. This study examined the interaction between [CO₂] and nitrogen (N) fertilization on the lodging of rice (Oryza sativa L.) using free-air CO₂ enrichment (FACE) systems installed in paddy fields at Shizukuishi, Iwate, Japan (39°38′N, 140°57′E). Rice plants were grown under two levels of [CO₂] (ambient = 365 μmol mol⁻¹; elevated [CO₂] = 548 μmol mol⁻¹) and three N fertilization regimes: a single initial basal application of controlled-release urea (8 g N m⁻², CRN), split fertilization with a standard amount of ammonium sulfate (9 g N m⁻², MN), and ample N (15 g N m⁻², HN). Lodging score (six ranks at 18° intervals, with larger scores indicating greater bending), yield, and yield components were measured at maturity. The lodging score was significantly higher under HN than under CRN and MN, but lodging was alleviated by elevated [CO₂] under HN. This alleviation was associated with the shortened and thickened lower internodes, but was not associated with a change in the plant's mass moment around the culm base. A positively significant correlation between lodging score and ripening percentage indicated that ripening percentage decreased by 4.5% per one-unit increase in lodging score. These findings will be useful to develop functional algorithm that can be incorporated into mechanistic crop models to predict rice production more accurately in a changing climate and with different cultural practices.     

Effects of different diets on utilization of nitrogen from cattle slurry applied to grassland on a sandy soil in The Netherlands

Dietary adjustments have been suggested as a means to reduce N losses from dairy systems. Differences in fertilizing value of dairy slurry as a result of dietary adjustments were evaluated in a 1-year grassland experiment and by long-term modelling. Slurry composition of non-lactating dairy cows was manipulated by feeding diets with extreme high and low levels of dietary protein and energy. C:N_total ratio of the produced slurries ranged from 5.1 to 11.4. To evaluate their short-term fertilizer N value, the experimental slurries (n = 8) and slurries from commercial farms with variable composition (n = 4), were slit-injected in two grassland fields on the same sandy soil series in the north of The Netherlands (53°10′N, 6°04′E), with differences in sward age and ground water level. The recently established grassland field (NEW) was characterized by lower soil OM, N and moisture contents, less herbs and more modern grass varieties compared to the older grassland field (OLD). Slurry was applied in spring (100 kg N ha⁻¹) and after the first cut (80 kg N ha⁻¹) while in total four cuts were harvested. Artificial fertilizer N treatments were included in the experiment to calculate the mineral fertilizer equivalent (MFE) of slurry N. The OLD field showed a higher total N uptake whereas DM yields were similar for the two fields. Average MFE of the slurries on the OLD field (47%) was lower than on the NEW field (56%), probably as a result of denitrification of slurry N during wet conditions in spring. Slurries from high crude protein diets showed a significantly higher MFE (P < 0.05) compared to low crude protein diets. No significant differences in MFE were observed between slurries from high and low energy diets. On both fields, MFE appeared to be positively related to the ammonium content (P < 0.001) and negatively to the C:N_total ratio of the slurry DM (P = 0.001). Simulation of the effect of long-term annual application of 180 kg N ha⁻¹ with highest and lowest C:N_total ratio suggested that both slurries would lead to an increase in annual soil N mineralization. Both soil N mineralization and SOC appeared to be substantially higher in equilibrium state for the slurry with the highest C:N_total ratio. It is concluded that in a situation with slit-injection, the reduced first-year N availability of slurry with a high C:N_total ratio as observed in the grassland experiment will only be compensated for by soil N mineralization on the very long term.     

A promising clean process for production of diosgenin from Dioscorea zingiberensis C. H. Wright

This study proposes a new approach for diosgenin production from Dioscorea zingiberensis C. H. Wright tubers with respect to resources utilization and clean production. This process consisted of two successive parts, i.e., recovery of starch from raw material, and microbial hydrolysis of the residue to produce diosgenin by Trichoderma reesei. In the first step, about 75.4% of hemicellulose and 98.0% of starch were removed from the tubers. In the second step, about 90.2% of diosgenin was released from saponins by T. reesei at 30 °C, at an aeration of 0.80 vvm and agitation rate of 300 rpm in a 5.0 L bioreactor. Significant reduction of pollutant production was detected by replacing the traditional approach with the proposed new method. About 99.2% of reducing sugar, 99.4% of chemical oxygen demand, 99.2% of total organic carbon, 100% of SO₄^2?, and 100% of acid was reduced in the new processing wastewater.     

Additional steps in mechanical recyling of PET

This study presents the laboratory scale results of an extra step in Poly (ethylene terephthalate) – PET mechanical recycling (grinding, washing, drying and reprocessing): a chemical washing after the conventional one. Cooking oil PET bottle flakes were washed in water and then subjected to a reaction with an aqueous solution of sodium hydroxide 5 M at 90 °C for 10 min (chemical washing). After rinsing and drying, the flakes were characterized by thermogravimetry, gas chromatography and elemental analysis tests. The results indicated that the chemically washed material had higher purity than PET washed only with water: 99.3% and 96.7%, respectively, which undoubtedly implies properties, applications and prices closer to those of virgin resin. The production of purified terephthalic acid (TPA) from the chemical washing residue was optimized and reached a purity of 99.6%. Despite the results, the use of chemically washed PET and of TPA obtained is not recommended for direct contact with food, since they still contain some impurities.     

Exceedance of modern ‘background’ fine-grained sediment delivery to rivers due to current agricultural land use and uptake of water pollution mitigation options across England and Wales

Excessive loss of fine-grained sediment to rivers is widely recognised as a global environmental problem. To address this issue, policy teams and catchment managers require an estimate of the ‘gap’ requiring remediation, as represented by the excess above ‘background’ losses. Accordingly, recent work has estimated the exceedance of modern ‘background’ sediment delivery to rivers at national scale across England and Wales due to (i) current agricultural land cover, cropping and stocking, and (ii) current land use corrected for the uptake of on-farm mitigation measures. This sectoral focus recognises that, nationally, agriculture has been identified as the principal source of fine sediment loss to the aquatic environment. Two estimates of modern ‘background’ sediment loss, based on paleolimnological evidence, were used in the analysis; the target modern ‘background’ (TMBSDR) and maximum modern ‘background’ (MMBSDR) sediment delivery to rivers. For individual (n = 4485) non-coastal water bodies, the sediment ‘gap’ in excess of TMBSDR and MMBSDR, due to current land cover, cropping and stocking, was estimated to range up to 1368 kg ha⁻¹ yr⁻¹ (median 61 kg ha⁻¹ yr⁻¹) and 1321 kg ha⁻¹ yr⁻¹ (median 19 kg ha⁻¹ yr⁻¹), respectively. The respective ranges in conjunction with current land cover, cropping and stocking but corrected for the potential impact of on-farm sediment mitigation measures were up to 1315 kg ha⁻¹ yr⁻¹ (median 50 kg ha⁻¹ yr⁻¹) and 1269 kg ha⁻¹ yr⁻¹ (median 8 kg ha⁻¹ yr⁻¹). Multiplication of the estimates of excess sediment loss corrected for current measure uptake, above TMBSDR and MMBSDR, with estimated maximum unit damage costs for the detrimental impacts of sediment pollution on ecosystem goods and services, suggested respective water body ranges up to 495 £ ha⁻¹ yr⁻¹ and 478 £ ha⁻¹ yr⁻¹. Nationally, the total loss of sediment in excess of TMBSDR was estimated at 1,389,818 t yr⁻¹ equating to maximum environmental damage costs of £523 M yr⁻¹, due to current structural land use, compared to 1,225,440 t yr⁻¹ equating to maximum damage costs of £462 M yr⁻¹ due the uptake of on-farm sediment control measures. The corresponding total loss of sediment in excess of MMBSDR was estimated at 1,038,764 t yr⁻¹ equating to maximum damage costs of £462 M yr⁻¹, compared with 890,146 t yr⁻¹ and £335 M yr⁻¹ correcting excess agricultural sediment loss for current implementation of abatement measures supported by policy instruments. This work suggests that the current uptake of sediment control measures on farms across England and Wales is delivering limited benefits in terms of reducing loadings to rivers and associated environmental damage costs.     

Performance and water-use efficiency (single-leaf vs. whole-canopy) of well-watered and half-stressed split-root Lambrusco grapevines grown in Po Valley (Italy)

‘Lambrusco a foglia frastagliata’ grapevines (Vitis vinifera L.) were grown outdoors at Piacenza (44°55′N, 9°44′E, Po Valley, Italy) with the root system split between two 30-L pots and subjected from pre-veraison (17 July) to harvest (5 September) to soil drying of half of the root system (HS) induced by withholding water from one of the two pots as compared to well-watered (WW) vines (both pots daily recharged at field capacity). Volumetric soil-water content, pre-dawn and mid-morning leaf water potential, single-leaf gas-exchange as assimilation rate, stomatal conductance and transpiration were monitored throughout the trial. Whole-canopy gas-exchange as net CO₂ exchange rate (NCER) and transpiration were tracked from 31 August to 7 September on three vines per treatment on a 24-h basis using an enclosure method. Primary leaf carbon isotope (δ¹³C) composition, yield components and must composition were determined at harvest.Withdrawing water from one pot triggered a water stress response showing higher stomatal sensitivity to changes in air vapour pressure deficit, relatively low assimilation rates, high intrinsic and extrinsic water-use efficiency (WUE) and earlier cessation of shoot growth. Yet, mid-morning leaf water potential was consistently lower in HS treatment over stress as compared to WW, indicating an anisohydric adjustment. Canopy NCER given on a leaf-area basis showed mean daily rates ranging from 3.9 to 4.9 μmol m² s^?1 in WW canopies against 2.6–3.0 μmol m^?2 s^?1 in HS. Conversely, canopy transpiration rates varied from 0.915 to 1.157 mmol m^?2 s^?1 for WW to 0.630–0.714 mmol m² s^?1 in HS. Increased leaf-based intrinsic and extrinsic WUE in HS did not match the canopy response, which to some extent resulted in an opposite outcome, i.e. higher canopy WUE in well-watered vines especially in the morning hours. Likewise, δ¹³C did not differ between treatments. This suggests caution when point-time determinations of single-leaf-based WUE are extrapolated to the whole-canopy behaviour when assessing the water saving strategies of a given genotype. The stressed vines achieved no variation in yield level and components and had improved grape composition as to soluble solids and total anthocyanins. This optimal behaviour is likely due to earlier shoot growth cessation, enhanced maturity and a buffering leaf-to-fruit ratio (3.61 m² kg^?1) that mitigated the effects of post-veraison stress.     

Natural dyeing of wool and hair with indigo carmine (C.I. Natural Blue 2), a renewable resource based blue dye

Indigo carmine can be used as a source of blue dye for wool and hair dyeing. The option to use indigo carmine in combination with other natural dyes in a one-bath procedure as a hybrid dyeing concept is of interest both for natural dyeing and for coloration of hair. The present study shows that indigo carmine dyeing on wool exhibits the substantial sorption in the range of pH 4–5 and temperature between 40 and 60 °C. Experiments with human hair samples indicate that the experiments on wool can serve as a model that can be applied for hair dyeing. Comparisons of the energy, water and chemical consumption between two-bath dyeing with indigo and natural dyes separately and a one-bath dyeing using indigo carmine together with other natural dyes demonstrates the advantages of the one-bath hybrid dyeing concept.     

A comparative study on the effect of GTAW processes on the microstructure and mechanical properties of P91 steel weld joints

Modified 9Cr-1Mo (P91) steel is widely used in the construction of power plant components. In the present study, a comparative study on influence of activated flux tungsten inert gas (A-TIG), and gas tungsten arc (GTA) welding processes on the microstructure and the impact toughness of P91 steel welds was carried out. P91 steel welds require a minimum of 47 J during the hydrotesting of vessels as per the EN1557: 1997 specification. Toughness of P91 steel welds was found to be low in the as-weld condition. Hence post-weld heat treatment (PWHT) was carried out on weld with the objective of improving the toughness of weldments. Initially as per industrial practice, PWHT at 760 °C – 2 h was carried out in order to improve the toughness of welds. It has been found that after PWHT at 760 °C – 2 h, GTA weld (132 J) has higher toughness than the required toughness (47 J) as compared with A-TIG weld (20 J). The GTA weld has higher toughness due to enhanced tempering effects due to multipass welding, few microinclusion content and absence of δ-ferrite. The A-TIG weld requires prolonged PWHT (i.e. more than 2 h at 760 °C) than GTA weld to meet the required toughness of 47 J. This is due to harder martensite, few welding passes that introduces less tempering effects, presence of δ-ferrite (0.5%), and more alloy content. After PWHT at 760 °C – 3 h, the toughness of A-TIG weld was improved and higher than the required toughness of 47 J.     

Analysis of temperature effects on seasonal and interannual variation in CH4 emission from rice-planted pots

Rice (Oryza sativa L.) paddies are one of the major sources of atmospheric methane (CH₄), a greenhouse gas. To elucidate the quantitative relationship between CH₄ emission from rice paddies and temperature, 6 years data of CH₄ emission from pot experiments were analyzed in terms of the sum of effective temperature (∑(T−15); T is the daily mean air temperature (°C)). The base temperature of 15 °C was adopted as the 0 °C physiological temperature for methanogens. Significant positive correlations between total CH₄ emission throughout the rice growth period and ∑(T−15) were observed for pots with rice straw (RS) application at a rate of 6 g kg⁻¹ soil, which corresponds to 6 t ha⁻¹ (r=0.830⁷¹), and those without RS application (r=0.818⁷¹). It was confirmed that temperature is a major factor affecting the interannual variation in CH₄ emission. For the 1993 and 1995 data sets that include seven and four levels of RS application, the relationship between seasonal CH₄ emission and RS application rate could be expressed using linear functions (r=0.988⁷¹, 0.996⁷¹), the slopes of which were similar to each other. Based on these findings, we confirmed that the dependence of seasonal CH₄ emission on both temperature and RS application rate can be described by a single linear equation.     

Innovative cleaner production for steel phosphorization using Zn–Mn phosphating solution

Phosphating prior to coating for steel is usually needed. In this paper, an innovative cleaner production has been developed for steel surface treatment using Zn–Mn phosphating solution in which there was no nitrite. The mass of the Zn–Mn layer deposited in this new process was about 1.1 g m^?2 when the temperature ranged from 3 to 35 °C. The corrosion time for the color phosphating layer in the copper sulfate spot test was in the range of 72–145 s. Adhesion test showed that the coating layers achieved a higher adhesion load than those produced by conventional methods. Washing using water was not necessary in this cleaner phosphorization, which usually follows phosphorization in traditional processes of steel phosphorization. Consequently, wastewater discharge was reduced greatly.     

Irrigation of olive groves in Southern Italy with treated municipal wastewater: Effects on microbiological quality of soil and fruits

The use of municipal wastewater in agriculture requires a careful monitoring of a range of hygiene parameters. Yearly hygienic impact assessments on soil and fruit were made between 2000 and 2006 in an olive (Olea europaea L.) grove established near a municipal wastewater treatment plant in Southern Italy (Ferrandina–Basilicata region, 40°29′ N, 16°28′ E). The experimental grove was managed in two plots. The first plot, non-tilled, was drip irrigated daily with reclaimed wastewater. The second plot was unirrigated (i.e. rainfed) and subject to conventional management for the region. Samples of wetted soil from different depths and of treated wastewater were analysed for Escherichia coli, enterococci, sulphite-reducing Clostridium spores and Salmonella spp. Fruits were collected both from the canopy and from nets spread on the ground and analysed for faecal contamination. The average annual quantity of wastewater distributed was 293 mm. E. coli concentration in the wastewater varied considerably, being frequently above the stringent Italian mandatory limit of 10 CFU 100 mL^?1 and also the WHO limit of 1000 MPN 100 mL^?1. Salmonella was never detected in the wastewater, the soil or on the fruit samples. Slight increases in the other bacteria were observed in the wastewater-irrigated soil during the irrigation season and especially in the top 10 cm. Soil resilience and bacterial mortality/inactivation probably explains the seasonal decrease of soil bacteria content over the 7 years of the study. Because of their high resistance to disinfection treatments and to environmental conditions, the spores of the sulphite-reducing bacterium Clostridium could be useful as an indicator of contamination in future guidelines that might be enacted for the use of wastewater in agriculture. No significant microbial contamination was recorded on fruit harvested directly from the canopy of the wastewater-irrigated trees. Contaminations on fruits sampled from the ground in the wastewater-irrigated plot were always low and usually similar to, or lower than those observed on drupes collected from the rainfed plot. In the rainfed plot, the recorded occasional contaminations were probably due to a number of factors, such as grazing of farm stock, presence of wild animals and surface water runoff from adjacent agricultural areas. This work confirms that, under suitable conditions, low-quality wastewater can be useful as an additional water resource for olive irrigation in water-scarce Mediterranean environments.     

Metal-cored arc welding process for joining of modified 9Cr-1Mo (P91) steel

In the present work, metal-cored arc welding process was used for joining of modified 9Cr-1Mo (P91) steel. Metal-cored arc welding process is characterized by high productivity, slag-free process, defect-free weldments that can be produced with ease, and good weldability. Toughness is essential in welds of P91 steel during hydro-testing of vessels. There is a minimum required toughness of 47 J for welds that has to be met as per the EN1557:1997 specification. In the present study, welds were completed using two kinds of shielding gases, each composition being 80% Argon + 20% CO₂, and pure argon respectively. Microstructural characterization and toughness evaluation of welds were done in the as – weld, PWHT at 760 °C – 2 h and PWHT at 760 °C – 5 h conditions. The pure argon shielded welds (‘A2’ and ‘B2’) have higher toughness than 80% argon + 20% CO₂ shielded welds (‘A1’ and ‘B1’). Pure argon shielded welds show less microinclusion content with low volume fraction of δ-ferrite (<2%) phase. Themo-calc windows (TCW) was used for the prediction of equilibrium critical transformation points for the composition of the welds studied. With increase in post-weld heat treatment (PWHT) duration from 2 h to 5 h, there was increase in toughness of welds above 47 J. Using metal-cored arc welding process, it was possible to achieve the required toughness of more than 47 J after PWHT at 760 °C – 2 h in P91 steel welds.