Spectroscopic characterization and solubility investigation on the effects of As(V) on mineral structure tooeleite (Fe6(AsO3)4SO4(OH)4·H2O)

Tooeleite is an unique ferric arsenite sulfate mineral, which has the potential significance of directly fixing As(III) as mineral trap. The tooeleite and various precipitates were hydrothermally synthesized under the different of initial As(III)/As(V) molar ratios and characterized by XRD, FTIR, XPS and SEM. The crystallinity of tooeleite decreases with the amount of As(V). The precipitate is free of any crystalline tooeleite at the level of that XRD could detect when the ratio of As(III)/As(V) of 7:3 and more. The characteristic bands of tooeleite are observed in 772, 340, 696 and 304 cm−1, which are assigned to the ν1, ν2, ν3 and ν4 vibrations of AsO33−. These intensities of bands gradually decreases with the presence of As(V) and its increasing. An obviously wide band is observed in 830 cm−1, which is the ν1 vibration of AsO4. The result of XPS reveals that the binding energies of As3d increase from 44.0 eV to 45.5 eV, which indicates that the amount of As(V) in the precipitates increases. The concentrations of arsenic released of these precipitates are 350–650 mg/L. The stability of tooeleite decreases by comparison when the presence of coexisting As(V) ions.

Abatement of aqueous anionic contaminants by thermo-responsive nanocomposites: (Poly(N-isopropylacrylamide))-co-silylanized Magnesium/Aluminun layered double hydroxides

A series of novel thermo-responsive composite sorbents, were prepared by free-radical co-polymerization of N-isopropylacrylamide (NIPAm) and the silylanized Mg/Al layered double hydroxides (SiLDHs), named as PNIPAm-co-SiLDHs. For keeping the high affinity of Mg/Al layered double hydroxides towards anions, the layered structure of LDHs was assumed to be reserved in PNIPAm-co-SiLDHs by the silanization of the wet LDH plates as evidenced by the X-ray powder diffraction. The sorption capacity of PNIPAm-co-SiLDH (13.5 mg/g) for Orange-II from water was found to be seven times higher than that of PNIPAm (2.0 mg/g), and the sorption capacities of arsenate onto PNIPAm-co-SiLDH are also greater than that onto PNIPAm, for both As(III) and As(V). These sorption results suggest that reserved LDH structure played a significant role in enhancing the sorption capacities. NO3− intercalated LDHs composite showed the stronger sorption capacity for Orange-II than that of CO32−. After sorption, the PNIPAm-co-SiLDH may be removed from water because of its gel-like nature, and may be easily regenerated contributing to the accelerated desorption of anionic contaminants from PNIPAm-co-SiLDHs by the unique phase-transfer feature through slightly heating (to 40 °C). These recyclable and regeneratable properties of thermo-responsive nanocomposites facilitate its potential application in the in-situ remediation of organic and inorganic anions from contaminated water.

An fMRI investigation of semantic and phonological naming treatment in aphasia

Di�culty naming objects is one of the most common impairments in people with aphasia post-stroke, irrespective of aphasia classification (Goodglass & Wingfield, 1997). Thus, remediation of naming impairments is often a focus of treatment in the rehabilitation of language. Such treatments typically employ phonological or semantic approaches, or a combination of the two, in order to target the major cognitive components involved in word retrieval (Nickels,2002). Although individuals can show greater benefit from one approach over the other, the relationship between an individual’s locus of breakdown in word retrieval and response to a particular treatment approach remains unclear, and knowledge of the underlying neural mechanisms which may be responsible for successful treatment is scarce. The aim of this study was to examine brain activity associated with successful phonological and semantic based treatments for word retrieval using functional Magnetic Resonance Imaging fMRI).

Soft-particle model analysis of effect of LPS on electrophoretic softness of Acidithiobacillus ferrooxidans grown in presence of different metal ions

The effect of Surface lipopolysaccharides (LPS) on the electrophoretic softness and fixed charge density in the ion-penetrable layer of Acidithiobacillus ferrooxidans cells grown in presence of copper or arsenic ions have been discussed, The electrophoretic mobility data were analyzed using the soft-particle electrophoresis theory. Cell surface potentials of all the strains based on soft-particle theory were lower than those estimated using the conventional Smoluchowski theory, Exposure to metal ions increased the Surface electrophoretic softness with decrease in the fixed charge density. Effect of cell surface lipopolysaccharides on the model parameters are investigated and discussed.

Effect of surface-applied treatments on the above-ground performance of simulated timber joinery

We examined the effect of surface-applied treatments on the above-ground decay resistance of the tenon of mortice-and-tenon timber joints designed to simulate joinery that is exposed to the weather. Joints made from untreated radiata pine, Douglas-fir, brush box, spotted gum and copper-chrome-arsenic (CCA) treated radiata pine were exposed to the weather for 9 y on above-ground racks at five sites throughout eastern Australia. Results indicate (1) a poorly maintained external paint film generally accelerated decay, (2) a brush coat of water-repellent preservative inside the joints often extended serviceability (in some cases by a factor of up to seven times that of untreated joints) and (3) the level of protection provided by a coat of primer applied inside the joint varied and in most cases was not as effective as the water-repellent preservative treatment.

Re-use of fluoride contaminated bone char sludge in concrete

Managing sludge generated by treating groundwater contaminated with geogenic contaminants (fluoride, arsenic, and iron) is a major issue in developing nations. Their re-use in civil engineering applications is a possible pathway for reducing the impact on the geo-environment. This paper examines the re-use of one such sludge material, namely, fluoride contaminated bone char sludge, as partial replacement for fine aggregate (river-sand) in the manufacture of dense concrete specimens. Bone char sludge is being produced by defluoridation of contaminated groundwater in Nalagonda District, Andhra Pradesh, India. The impact of admixing 1.5-9% sludge contents on the compression strength and fluoride leaching potential of the sludge admixed concrete (SAC) specimens are examined. The compression strengths of the SAC specimensa re examined with respect to strength criteria for manufacture of dense, load-bearing concrete blocks. The fluoride release potential of the SAC specimens is examined with respect to standards specific to disposal of treated leachate into inland surface water.

Detecting the attributes of a wheat crop using digital imagery acquired from a low-altitude platform

A low-altitude platform utilising a 1.8-m diameter tethered helium balloon was used to position a multispectral sensor, consisting of two digital cameras, above a fertiliser trial plot where wheat (Triticum spp.) was being grown. Located in Cecil Plains, Queensland, Australia, the plot was a long-term fertiliser trial being conducted by a fertiliser company to monitor the response of crops to various levels of nutrition. The different levels of nutrition were achieved by varying nitrogen application rates between 0 and 120 units of N at 40 unit increments. Each plot had received the same application rate for 10 years. Colour and near-infrared images were acquired that captured the whole 2 ha plot. These images were examined and relationships sought between the captured digital information and the crop parameters imaged at anthesis and the at-harvest quality and quantity parameters. The statistical analysis techniques used were correlation analysis, discriminant analysis and partial least squares regression. A high correlation was found between the image and yield (R2 = 0.91) and a moderate correlation between the image and grain protein content (R2 = 0.66). The utility of the system could be extended by choosing a more mobile platform. This would increase the potential for the system to be used to diagnose the causes of the variability and allow remediation, and/or to segregate the crop at harvest to meet certain quality parameters.

Understanding coal seam gas associated water, regulations and strategies for treatment

The coal seam gas (CSG) industry is globally of potentially great importance economically. This study exemplifies the complex relationship between land use and management, groundwater impact and associated water treatment especially in relation to Queensland where a significant increase in the amount of gas extracted over the past 6 years has occurred. In order to effectively manage the environmental impact of the CSG industry it is necessary to appropriately understand the nature of the gas deposits, methods for gas collection, the physicochemical composition of the by-product associated water and the technologies available for water remediation. Australia is mainly considered arid and semi-arid and thus there is a need to not only beneficially reuse water resources but also protect existing ground water reservoirs such as the Great Artesian Basin (GAB). This paper focussed primarily on the Surat Basin located in Queensland and northern New South Wales. The mechanism for CSG formation, relation to local geological features, extraction approach and the potential impact/benefits of associated water was discussed. An outline of the current legislative requirements on physical and chemical properties of associated water in the Surat Basin was also provided, as well as the current treatment technologies used by the major CSG companies. This review was of significance in relation to the formulation of the most appropriate and cost effective management of associated water, while simultaneously preserving existing water resources and the environment.

Lukemisen vaikeuden kuntoutus ensiluokkalaisilla : Kolme pedagogista interventiota

Remediation of Reading Difficulties in Grade 1. Three Pedagogical Interventions Keywords: initial teaching, learning to read, reading difficulties, intervention, dyslexia, remediation of dyslexia, home reading, computerized training In this study three different reading interventions were tested for first-graders at risk of reading difficulties at school commencement. The intervention groups were compared together and with a control group receiving special education provided by the school. First intervention was a new approach called syllable rhythmics in which syllabic rhythm, phonological knowledge and letter-phoneme correspondence are emphasized. Syllable rhythmics is based on multi-sensory training elements aimed at finding the most functional modality for every child. The second intervention was computerized training of letter-sound correspondence with the Ekapeli learning game. The third intervention was home-based shared book reading, where every family was given a story book, and dialogic reading style reading and writing exercises were prepared for each chapter of the book. The participants were 80 first-graders in 19 classes in nine schools. The children were matched in four groups according to pre-test results: three intervention and one control. The interventions took ten weeks starting from September in grade 1. The first post-test including several measures of reading abilities was administered in December. The first delayed post-test was administered in March, the second in September in grade 2, and the third, “ALLU” test (reading test for primary school) was administered in March in grade 2. The intervention and control groups differed only slightly from each other in grade 1. However, girls progressed significantly more than boys in both word reading and reading comprehension in December and this difference remained in March. The children who had been cited as inattentive by their teachers also lagged behind the others in the post-tests in December and March. When participants were divided into two groups according to their initial letter knowledge at school entry, the weaker group (maximum 17 correctly named letters in pre-test) progressed more slowly in both word reading and reading comprehension in grade 1. Intervention group and gender had no interaction effect in grade 1. Instead, intervention group and attentiveness had an interaction effect on most test measures the inattentive students in the syllable rhythmic group doing worst and attentive students in the control group doing best in grade 1. The smallest difference between results of attentive and inattentive students was in the Ekapeli group. In grade 2 still only minor differences were found between the intervention groups and control group. The only significant difference was in non-word reading, with the syllable rhythmics group outperforming the other groups in the fall. The difference between girls’ and boys’ performances in both technical reading and text comprehension disappeared in grade 2. The difference between the inattentive and attentive students cold no longer be found in technical reading, and the difference became smaller in text comprehension as well. The difference between two groups divided according to their initial letter knowledge disappeared in technical reading but remained significant in text comprehension measures in the ALLU test in the spring of grade 2. In all, the children in the study did better in the ALLU test than expected according to ALLU test norms. Being the weakest readers in their classes in the pre-test, 52.3 % reached the normal reading ability level. In the norm group 72.3 % of all students attained normal reading ability. The results of this study indicate that different types of remediation programs can be effective, and that special education has been apparently useful. The results suggest careful consideration of first-graders’ initial reading abilities (especially letter knowledge) and possible failure of attention; remediation should be individually targeted while flexibly using different methods.

Tertiary Treatment of Ayr Municipal Wastewater using Bioremediation: A Pilot-Scale Study. A Report Prepared for the Burdekin Shire Council and the Burdekin Rangeland Reef Initiative

This joint DPI/Burdekin Shire Council project assessed the efficacy of a pilot-scale biological remediation system to recover Nitrogen (N) and Phosphorous (P) nutrients from secondary treated municipal wastewater at the Ayr Sewage Treatment Plant. Additionally, this study considered potential commercial uses for by-products from the treatment system. Knowledge gained from this study can provide directions for implementing a larger-scale final effluent treatment protocol on site at the Ayr plant. Trials were conducted over 10 months and assessed nutrient removal from duckweed-based treatments and an algae/fish treatment – both as sequential and as stand-alone treatment systems. A 42.3% reduction in Total N was found through the sequential treatment system (duckweed followed by algae/fish treatment) after 6.6 days Effluent Retention Time (E.R.T.). However, duckweed treatment was responsible for the majority of this nutrient recovery (7.8 times more effective than algae/fish treatment). Likewise, Total P reduction (15.75% reduction after 6.6 days E.R.T.) was twice as great in the duckweed treatment. A phytoplankton bloom, which developed in the algae/fish tanks, reduced nutrient recovery in this treatment. A second trial tested whether the addition of fish enhanced duckweed treatment by evaluating systems with and without fish. After four weeks operation, low DO under the duckweed blanket caused fish mortalities. Decomposition of these fish led to an additional organic load and this was reflected in a breakdown of nitrogen species that showed an increase in organic nitrogen. However, the Dissolved Inorganic Nitrogen (DIN: ammonia, nitrite and nitrate) removal was similar between treatments with and without fish (57% and 59% DIN removal from incoming, respectively). Overall, three effluent residence times were evaluated using duckweed-based treatments; i.e. 3.5 days, 5.5 days and 10.4 days. Total N removal was 37.5%, 55.7% and 70.3%, respectively. The 10.4-day E.R.T. trial, however, was evaluated by sequential nutrient removal through the duckweed-minus-fish treatment followed by the duckweed-plus-fish treatment. Therefore, the 70.3% Total N removal was lower than could have been achieved at this retention time due to the abovementioned fish mortalities. Phosphorous removal from duckweed treatments was greatest after 10.4-days E.R.T. (13.6%). Plant uptake was considered the most important mechanism for this P removal since there was no clay substrate in the plastic tanks that could have contributed to P absorption as part of the natural phosphorous cycle. Duckweed inhibited phytoplankton production (therefore reducing T.S.S) and maintained pH close to neutral. DO beneath the duckweed blanket fell to below 1ppm; however, this did not limit plant production. If fish are to be used as part of the duckweed treatment, air-uplifts can be installed that maintain DO levels without disturbing surface waters. Duckweed grown in the treatments doubled its biomass on average every 5.7 days. On a per-surface area basis, 1.23kg/m2 was harvested weekly. Moisture content of duckweed was 92%, equating to a total dry weight harvest of 0.098kg/m2/week. Nutrient analysis of dried duckweed gave an N content of 6.67% and a P content of 1.27%. According to semi-quantitative analyses, harvested duckweed contained no residual elements from the effluent stream that were greater than ANZECC toxicant guidelines proposed for aquaculture. In addition, jade perch, a local aquaculture species, actively consumed and gained weight on harvested duckweed, suggesting potential for large-scale fish production using by-products from the effluent treatment process. This suggests that a duckweed-based system may be one viable option for tertiary treatment of Ayr municipal wastewater. The tertiary detention lagoon proposed by the Burdekin Shire Council, consisting of six bays approximately 290 x 35 metres (x 1.5 metres deep), would be suitable for duckweed culture with minor modification to facilitate the efficient distribution of duckweed plants across the entire available growing surface (such as floating containment grids). The effluent residence time resulting from this proposed configuration (~30 days) should be adequate to recover most effluent nutrients (certainly N) based on the current trial. Duckweed harvest techniques on this scale, however, need to be further investigated. Based on duckweed production in the current trial (1.23kg/m2/week), a weekly harvest of approximately 75 000kg (wet weight) could be expected from the proposed lagoon configuration under full duckweed production. A benefit of the proposed multi-bay lagoon is that full lagoon production of duckweed may not be needed to restore effluent to a desirable standard under the present nutrient load, and duckweed treatment may be restricted to certain bays. Restored effluent could be released without risk of contaminating the receiving waterway with duckweed by evacuating water through an internal standpipe located mid-way in the water column.

Constructed mangrove wetland project

This article describes research undertaken in 2000 into using magroves in wastewater remediation ponds for prawn farms.

Growing banana prawns in prawn farm settlement ponds to utilise and help remove waste nutrients.

To assess their utility for profitable wastewater bioremediation, banana prawns, Penaeus (Fenneropenaeus) merguiensis (de Man), were stocked at low densities (1 – 5 m-2) and grown without supplemental feeding in five commercial-prawn-farm settlement ponds (0.3 to 6.0 ha). The prawns free-ranged in the variously designed ponds for 160 to 212 days after stocking as PL15. Survival estimates ranged from 12% to 60% with production of 50 – 528 kg ha-1. Over 1150 kg of marketable product was produced in the study. Exceptional growth was monitored at one farm where prawns reached an average size of 17g in 80 days. Nutrients in water flowing into (8 - 40 ML d-1) and out of the settlement pond at that farm were assessed twice weekly along with routine water quality measurements. Only small differences in water qualities were detected between waters running into and out of this settlement pond. Total nitrogen levels gradually increased from 1 - 1.5 mg L-1 early in the season to over 3 mg L-1 towards the end of the season. Total phosphorus levels similarly rose from 0.1 - 0.2 mg L-1 to 0.3 - 0.4 mg L-1 in the middle of the season, but fell to 0.2 – 0.3 mg L-1 towards the end when approximately 12,000 prawns were harvested with a total weight of 175 kg. No significant differences (P > 0.05) were detected in the overall acceptability of prawns harvested from each of the 5 settlement ponds in small-scale consumer sensory analyses. The prawns from settlement ponds were rated similarly to banana prawns grown with commercial diets at two other establishments. Microbiological analyses of prawns from all farms showed bacterial levels to be well within food-grade standards and lower than prawns produced in a normal growout pond. These results demonstrate that high quality food grade banana prawns can be produced in these wastewater treatment systems.

Nutrient levels in experimental tanks supplied with prawn pond effluent: the effect of artificial substrate and different densities of the banana prawn Penaeus merguiensis (de Man)

To experimentally investigate the effect of vertical artificial substrate and different densities of the banana prawn Penaeus (Fenneropenaeus) merguiensis on nutrient levels in prawn pond effluent, a time series experiment was conducted in a replicated tank system supplied periodically with discharge from a prawn production pond. Few differences (P>0.05) were detected between tanks without prawns, and tanks with low densities (5 prawns in 1700 litres) of prawns (10-12 g), in terms of nitrogen and phosphorus in the water column over the 28-day experimental period. Higher densities of prawns (starting at 25 or 50 per tank) caused an elevation of these macronutrients in the water column. This was partly due to prawn biomass losses from mortalities and weight reductions in the tank system. The survival and condition of prawns was significantly (P<0.05) reduced in tanks at these higher densities. The presence of artificial substrate (2 m2 tank-1) did not affect (P>0.05) the levels of nutrients in tank water columns, but significantly (P<0.05) increased the amount of nitrogen in tank residues left at the end of the trial when no prawns were present. The prawns had obviously been grazing on surfaces inside the tanks, and their swimming actions appeared to keep light particulate matter in suspension. Higher prawn densities increased microalgal blooms, which presumably kept ammonia levels low, and it is suggested that this association may provide the means for improved remediation of prawn farm effluent in the future.

Investigations into the potential for mixed cultures of banana prawns Penaeus merguiensis, sea mullet Mugil cephalus and rabbitfish Siganus nebulosus for bioremediation of aquaculture waste

To experimentally investigate the potential of mixed species polycultures for bioremediation of nutrient rich prawn farm effluent, a series of experiments was performed with banana prawns Penaeus (Fenneropenaeus) merguiensis, sea mullet Mugil cephalus and rabbitfish Siganus nebulosus to determine their compatibilities during particular life stages. Rabbitfish demonstrated a high tendency to prey upon banana prawn juveniles when no other food was available. Mullet of various sizes did not appear to prey upon banana prawn postlarvae (PL16) or juveniles in a fed or unfed environment. The study confirms the good potential for mullet and banana prawn polycultures.

Testing the effectiveness of the SKIM foam fractionator to reduce nutrient levels in prawn farm effluent

To experimentally investigate the effect of the “SKIM” mechanical foam fractionator on suspended material and the nutrient levels in prawn farm effluent, a series of standardised short-term treatments were applied to various effluent types in a static 10,000-litre water body. Prawn pond effluents were characterised by watercolour and dominance of phytoplankton species. Three effluent types were tested, namely 1) particulate-rich effluent with little apparent phytoplankton, 2) green mircoalgal bloom predominately made up of single celled phytoplankton, and 3) brown microalgal bloom with higher prevalence of diatoms. The effluent types were similar (P>0.05) in non-volatile particulate material, and nitrate/nitrite but varied from each other in the following ways: 1) The particulate-rich effluents were lower (P<0.05) in volatile solids (compared to brown blooms), total Kjeldahl nitrogen, dissolved organic nitrogen, dissolved organic phosphorus and chlorophyll a (compared to both green and brown blooms). 2) The brown blooms were higher (P<0.05) in ammonia (compared to green blooms), total nitrogen and total phosphorus (compared to both green and particulate-rich effluent), but were lower (P<0.05) in inorganic phosphorus (compared to both green and particulate-rich effluent). 3) The green blooms were higher (P<0.05) in dissolved (both organic and inorganic) phosphorus (compared to both brown and particulate-rich effluents). Although the effluent types varied significantly in these aspects the effect of the Skim treatment was similar for all parameters measured except total phosphorus. Bloom type and Skim-treatment period significantly (P<0.05) affected total Kjeldahl phosphorus concentrations. For all effluent types there was a continuous significant reduction (P<0.05) in total Kjeldahl phosphorus during the initial 6-hour treatment period. Levels of total suspended solids and volatile suspended solids in all effluent types were significantly (P<0.05) reduced in the first 2 hours but not thereafter. Non-volatile suspended solids were also significantly (P<0.05) reduced in the first 2 hours (30 to 40 % reduction) and a further 40% reduction occurred in the particulate-rich effluent over the next 2 hours. Mean values for total ammonia, dissolved organic nitrogen, total Kjeldahl nitrogen, total nitrogen, chlorophyll a and dissolved organic or inorganic phosphorus levels were not significantly (P>0.05) affected by the Skim unit in any bloom type during the initial 6 hours of testing. Nevertheless, non-significant nitrogen reductions did occur. Foam production by the Skim unit varied with different blooms, resulting in different concentrate volumes and different end points for separate experiments. Concentrate volumes were generally high for the particulate-rich and green blooms (175 – 370 litres) and low for the brown blooms (25 – 80 litres). This was due to the low tendency of the brown bloom to produce foam. This generated higher nutrient concentrations in the associated condensed foam, but may have limited the treatment efficiency. The results suggest that in this application, the Skim unit did not remove micro-algae as effectively as was anticipated. However, it was effective at removing other suspended solids. Considering these attributes and the other uses of this machinery documented by the manufactures, the unit’s oxygenation mixing capacities coupled with inorganic solids removal may provide a suitable mechanism for construction of a continuously mixed bioreactor that utilises the filtration and profit making abilities of bivalves.