Uptake and Accumulation of Anthropogenic Os in Free-Living Bank Voles (Myodes glareolus)

Chitosan is a biodegradable cationic polymer that may be a potential substitute for aluminum salts in water treatment systems. In our study, we compared the coagulation performances of chitosan with those of coagulant mixtures of chitosan and aluminum sulfate and chitosan and poly-aluminum chloride, respectively. The coagulation efficiency was evaluated in terms of coagulant dosage, solution pH, settling velocity of flocs, floc diameter, and water turbidity. The optimum dosages for acid-soluble and water-soluble chitosan required for removal of a bentonite suspension (100 NTU) were only 1.25 and 1.50 mg/l, respectively, at a respective efficiency of 99.2% and 95.8%. The optimal dosage range for water-soluble chitosan was broader than that for acid-soluble chitosan. The coagulation of bentonite decreased with increasing pH when acid-soluble chitosan was the coagulant. In contrast, the coagulation efficiency of bentonite was not affected at pH 5?C9 when water-soluble chitosan was the coagulant. The mixing of chitosan with alum or PAC in a 1:1 mass ratio significantly improved the coagulation process in terms of preventing the occurrence of re-stabilization. The highest floc settling velocity occurred at a dosage of 5?C6 mg/l of the coagulant mixtures, which was also the highest coagulation efficiency. Given the relatively high cost of chitosan and the good coagulation performance of the coagulant mixtures, we suggest that a 1:1 mass ratio of chitosan mixed with alum or PAC may be an alternative method to the use of pure chitosan in water treatment systems.     

壳聚糖-高岭土复合体去除铜绿微囊藻的试验研究

利用室内模拟试验,研究了壳聚糖和高岭土单独及复合作用对铜绿微囊藻的去除效果。以250mL烧杯作为试验容器,纯种藻为试验用藻,以叶绿素a和浊度表征藻液浓度的变化。结果表明,单独使用高岭土除藻效率较低,增加高岭土用量难以提高藻的去除率;单独使用壳聚糖对藻的去除效果较好,但是藻的絮凝沉降速度较慢。壳聚糖-高岭土复合体可以明显加快藻类的沉降速率,改善除藻效果。     

Water treatment sludge: a potential plant growth medium

Abstract. The disposal of water treatment sludge produced when turbid water is treated with flocculants (alum and polyDADMAC) and filtered for clarification is becoming increasingly expensive in South Australia. The physical and chemical properties of the sludge suggest that it might be used as a plant growth medium, and a glasshouse experiment compared the growth and elemental composition of broad beans in both alum and polyDADMAC sludge applied at different rates.
Dry matter production differed significantly between treatments. Poly + Fertilizer (F) and Poly 4%+ F produced the most dry matter. The Alum + F treatment produced significantly less dry matter than the Poly + F treatment but it was not significantly different from the control. The difference in plant growth between the pure poly and pure alum treatments resulted from increased availability of the fertilizer phosphorus in the poly sludge and the supply of some potassium and nitrogen by the poly sludge. Fertilizer was required for optimum plant growth. Greater rates of fertilizer may be required if alum sludge is to be used as a growth medium, than if poly sludge is used.
There was no evidence that aluminium toxicity would be a problem if water treatment sludges are used as growth media. The physical properties of the sludges (i.e. water holding capacity, drainage characteristics and structural stability) are probably more important than their inherent nutrient levels, although poly sludge does supply some nitrogen and does not fix phosphorus to the same extent as alum sludge.     

Study of the Effect of Saline Solution on the Extraction of the Moringa oleifera Seed’s Active Component for Water Treatment

Several coagulants/flocculants have been studied in order to remove the color and turbidity of raw water, employing natural ones demonstrated advantages in relation to chemicals. Moringa oleifera Lam is a natural polymer that has been gaining prominence in water treatment. It acts as a clarifying agent, providing a cationic protein that destabilizes the particles contained in a liquid medium. The main objective of the present work is to study the efficiency in terms of removing color and turbidity of raw water in order to obtain drinking water. For this purpose, different coagulant solutions were obtained utilizing three solutions of KCl in different concentrations (0.01, 0.1, and 1 M) and pure water combined with M. oleifera Lam seed. Each coagulant solution obtained was studied with concentrations ranging from 50 to 600 ppm of Moringa in solution. The pH was varied (4.0, 6.0, and 8.0) with 25% and 50% sodium hydroxide solution (NaOH) and hydrochloric acid (HCl), respectively. The tests were conducted with the “Jar Test Device” and the efficiency of the process was evaluated regarding the reduction of color and turbidity. The best results were found employing the coagulant solutions extracted with 1 M salt solution, pH 8.0, and different concentrations of coagulant solution. It is important to explain that the best results were in various concentration ranges, as the concentration of protein in solution becomes higher, the greater is its power as a coagulant. The lowest content of protein was found in the solution extracted with water, which consequently had the lowest values of color and turbidity removal.     

Removal of Iron and Manganese from Water with a High Organic Carbon Loading. Part I: The Effect of Various Coagulants

Iron and manganese removal from water is considered a routine operation in most potable water treatment plants. However, when there is dissolved organic carbon (DOC) present in the water source, it can significantly influence the success of iron and manganese removal. This investigation focused on the use of two different coagulants, alum and ferrichloride, used in conjunction with hydrogen peroxide as an oxidant, to reduce dissolved iron and manganese in water with a high DOC loading. The two coagulants behaved in a totally different manner during the treatment process, with alum being successful in reducing the iron content in the treated water, and ferrichloride yielding a good removal of the dissolved manganese present. Since these results were only possible in cases where hydrogen peroxide concentrations were also present, it was concluded that treatment with a single reagent would not yield the desired removal of contaminants from this specific water. Both treatment options significantly reduced the DOC levels in the water to below the desired concentration after treatment.     

Alum Sludge Dewatering Using Moringa oleifera as a Conditioner

An active component of Moringa oleifera (MO) has been used in comparison with synthetic polymers and alum for the conditioning of chemical sludge from a drinking water treatment plant. The comparison was based on dewatering characteristics of the conditioned sludge determined by capillary suction time (CST), specific resistance to filtration (SRF), sand column drainage and shear strength tests. The results indicated that MO showed comparable conditioning effect as alum. Polyelectrolytes were more effective than MO and alum. Sludge conditioned with MO and alum, as in dual chemical conditioning, showed better results than MO alone. According to CST, SRF and sand drainage results, optimum doses for MO, alum and polyelectrolytes were 125, 63, and 1.8 kg/t, respectively. Comparison of the two polyelectrolytes showed that the cationic polyelectrolyte was more effective. For sand drainage tests both polyelectrolytes improved the drainage rate by 2 orders of magnitude. MO and alum improved the drainage rate by about 4.2 times. On the other hand, the improvements in cake solids concentration were similar for all the chemical conditioners. Flocs from MO and alum were relatively stronger compared to those of the polyelectrolytes. From the results of the study it could be concluded that MO alone or in combination could be effectively used and replace alum for dewatering of chemical sludge.     

改性高岭土对水体中氮磷去除效果的研究

利用恒温振荡试验,研究了酸、碱、盐改性高岭土对水体中氮、磷去除效果的影响。结果表明,各处理高岭土对水体中氮、磷的吸附速率均较快,在2 h内均能达到吸附平衡。由Freundlich等温吸附方程模拟得出各处理高岭土对氮的吸附能力大小为Al处理〉Ca处理〉碱处理〉Mg处理〉原土〉酸处理;对磷的则为Al处理〉Mg处理〉Ca处理〉酸处理〉原土〉碱处理。由Langmuir等温吸附曲线方程得出各处理高岭土对氮的理论饱和吸附量顺序为Mg处理〉Ca处理〉碱处理〉Al处理〉原土〉酸处理;对磷的则为Al处理〉Ca处理〉Mg处理〉酸处理〉原土〉碱处理。各处理高岭土去除氮的适宜pH值为5.5-8.5,去除磷的适宜pH值为4-8.5。     

OPTIMUM DESIGN OF SEDIMENTATION TANKS BASED ON SETTLING CHARACTERISTICS OF KARACHI TANNERY WASTES

A study was carried out in a specially designed settling column to investigate the settling characteristics of effluents arising from Karachi tanneries. The Jar-tests were conducted to determine the optimum dosage of coagulants such as potash alum and ferric chloride to maximize the removal of suspended solids (S.S) from the wastes. For alum, the optimum dosage was found to be 150 mg L^-1, whereas with ferric chloride it was 30 mg L^-1. Experiments carried out in the settling column with the optimum coagulant dosages showed that the coagulation with ferric chloride was much better than with alum, as it removes about 84% S.S from the wastes compared to 70% removal obtained in case of alum. Design curves in terms of percent removal of S.S. vs loading rate and detention time were constructed using data obtained from settling column. These curves can be used in designing the settling tanks employed in the tannery wastes treatment plants.     

Potassium release on drying of soil samples from a variety of weathering regimes and c clay mineralogy in China

Thirty two soil samples from China were analyzed for exchangeable K before and after drying. Most soil samples were higher in exchangeable K after air-drying and ovendrying (60°C) than when wet. Soil clay minerals, especially clay-size mica, affected K released in air-dry and oven-dry samples. According to composition of clay minerals of air-dried samples, five classes were recognized. Soil samples with high mica and montmorillonite have the highest exchangeable K. Samples that contained higher kaolinite than mica had lower exchangeable K. Samples with higher kaolinite than quartz and mica had still lower exchangeable K. Samples of sandy soils contained very low exchangeable K. When quartz was the main mineral, the samples that had kaolinite and gibbsite as the main clay minerals had very low exchangeable K. The degree of weathering (weathering mean) bore an inverse relationship to the amount of K released on drying in air or at 60°C. Udults and Udalfs (Red Earths) of southeastern China, because of their high K release on being dried, are inferred to have received fine mica from the Western Desert dust rainout, reported to Liu et al. (1981).     

Use of Clay Dispersed in Water for Decreasing Soil Water Repellency

In this study, we examined the efficiency of a kaolinite clayey soil to mitigate water repellency of a sandy soil with olive trees. The treatment was applied to the soil zone below the tree canopy, which displayed the highest degree of water repellency [average water drop penetration time (WDPT) value = 820 s]. Both dry (incorporated onto the top soil) and wet clay applications (after dispersion in irrigation water) were examined in a replicated experiment, with control trees being used for comparison. The application rate of the clayey soil was maintained in both cases (wet and dry mode) equal to 1 kg m⁻², while the effect of subsequent wetting and drying cycles on the treatment performance was evaluated. The results of the study verify that clay application was effective to mitigate soil water repellency. Dry supplementation displayed low efficiency (26% reduction of the air‐dry WDPT compared with the control soil) within the first week of application. The efficiency of the dry‐clay treatment increased to 76% after applying three subsequent wetting and drying cycles. In comparison with the dry mode, the wet clay was efficient immediately after application (74% reduction of the WDPT), indicating that the limiting step in the overall process was clay dispersion. Based on the findings of this study, it was proposed that wet clay application is of interest for controlling soil water repellency in agricultural land. Copyright © 2016 John Wiley & Sons, Ltd.     

Removal of Heavy Metals from Soils using Enhanced Electrokinetic Soil Processing

In order to remediate contaminated land, a new process of electrokinetic purging of heavy metals from saturated soil is examined by laboratory experiments. Electrokinetic soil remediation is one of the most promising soil decontamination processes as it has high removal efficiency and time-effectiveness in low permeability soils such as clay. Being combined with several mechanisms-electromigration, electroosmosis, diffusion and electrolysis of water, electrokinetic soil processing can remove non-polar organics as well as ionic contaminants. This study suggests that the removal efficiencies for Pb and Cd are significantly influencedby applied voltage and current, type of purging solutions, soilpH, permeability and zeta potential of soil. The removal efficiencies for Pb and Cd were 75–85% for the kaolinite soil and 50–70% for the tailing soil over the duration of 4 days. For heavy metals, their adsorption capacities on the soil surface and mobilities in soil have significant effects on the removal efficiency.     

Evaluation of Magnetic Coagulant (α-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>-MO) and its Reuse in Textile Wastewater Treatment

The textile industries are characterized as one of the biggest consumers of potable water and chemical products throughout its process, being responsible for the elevated wastewater generation with intense coloration and wide polluting potential. In this context, the present study proposes the development and application of a new coagulant material for textile wastewater treatment. The proposed coagulant (α-Fe₂O₃-MO) was composed by hematite nanoparticles (α-Fe₂O₃) obtained by a simple non-pollutant methodology, associated with Moringa oleifera (MO) seeds saline extract compounds. Coagulation/flocculation (CF) efficiency was evaluated by removal of physicochemical parameters such as apparent color, turbidity, and compounds with absorption at UV_254nm (UV_254nm) through CF tests carried out on Jar test equipment and sedimentation carried out in the presence and absence of external magnetic field (600 k Am^?1). Kinetics sedimentation was from 0 to 90 min. The use of this new coagulant allowed the removal of 92.37% for apparent color, 91.43% for turbidity, and 46.09% for UV_254nm, indicating that the proposed coagulant association was efficient in the treatment of this type of wastewater under external magnetic field with only 10 min of sedimentation. In addition, the resulting sludge from CF process was tested as base material for a new coagulant synthesis, demonstrating great reuse potential. Therefore, the new proposed coagulant, composed of α-Fe₂O₃ and the compounds present in the seed extract of MO, has applicability for textile wastewater treatment demonstrating high removal rate for all evaluated parameters with cost reduction in the proposed treatment for this wastewater.     

Influence of Natural Organic Matter (NOM) on the Speciation of Aluminum during Water Treatment

Natural organic matter (NOM) is a term collectively used to describe the complex matrix of organic material present in natural waters. The impact of NOM on the speciation of aluminum at Buffalo Pound water treatment plant was evaluated in the present study using fulvic acid. The first stage of the study was to conduct aluminum (Al) speciation experiments (using background dissolved organic carbon levels present in the raw water) at the pilot scale water treatment plant located within the main plant changing the aluminum sulfate (alum) dose from 68 mg L^-1 (yearly average dose of the main plant) to 34 mg L^-1. The second stage of the study was to conduct jar tests at various alum/DOC ratios. Pilot scale speciation study showed that when the alum/DOC ratio was 5.3, most of the total aluminum in the filtered water was in the form of particulate aluminum. Such an increased particulate aluminum level did not increase the finished water turbidity. Soluble organic aluminum also increased compared to the level in raw water when the alum/DOC ratio was 5.3. Al speciation study conducted during jar testing showed that organically bound aluminum increased from 8 μg L^-1 (raw water) to 15 μg L^-1 in the finishedwater when the alum/DOC = 1.37. Jar test results also showed that an alum/DOC of at least 7.3 should be maintained in the main plant in order to meet the proposed operating guidelines of 100 μg L^-1 of total aluminum by Health Canada given the conditions that finished water soluble aluminum levels may be in the range of 35–40 μg L^-1.     

Accumulation of Cadmium,Chromium, and Zinc by the Moss Sphagnum Papillosum Lindle

In a series of laboratory experiments employing radiotracer methodology, the uptake of Cd,Cr, and Zn by Sphagnum papillosum Lindle moss from solutions of deionized water and bogwater was investigated. Bioaccumulation of the metals was a passive process, since living anddead moss accumulated metal equally. No significant differences were found in metal uptake ratesfrom single metal solutions and mixed metal solutions, suggesting insignificant competitionbetween the metals occurred at the low concentration range used (10-10 to 10-7 M). Metaluptake conformed with Freundlich adsorption isotherms. Concentration factors of metals inSphagnum papillosum in bog water (103 for Cd and Zn, 102 for Cr) were lower than in deionizedwater (104 for Cd and Zn, 103 for Cr), possibly due to metal complexation by dissolved organicmatter, competition by other major cations present in the bog water (Na+, K+, Mg2+, Ca2+) orcomplexation by chlorides in the bog water. While earlier studies have demonstrated the potentialof using sphagnum mosses for monitoring environmental metal contamination, these experimentsare the first to assess metal uptake in moss using low, environmentally realistic metalconcentrations. The results confirm that mosses would be very effective bioindicators ofenvironmental metal concentrations because the concentration of metal in the moss rapidly anddirectly reflects the metal concentrations in the ambient water.     

粪肥添加明矾对降低农田磷和重金属流失的作用

施用粪肥引起农田氮、磷流失的增加已引起人们广泛的关注。为了解粪肥中添加明矾可否降低农田污染物的流失,采用化学分析与田间试验相结合的方法研究了添加明矾对粪肥中水溶性养分和重金属浓度及施粪肥后农田养分、重金属流失的影响。结果表明,粪肥中添加明矾可大大降低其中的水溶性P和重金属浓度,其中水溶性P的下降幅度达79.3%。添加明矾后,粪肥施入农田形成的径流中P和重金属浓度明显低于不添加明矾的处理。但添加明矾对农田可溶性总N、NO3-N和NH4-N流失的影响不大。粪肥中添加明矾不会引起地表径流中铝浓度明显增加,对蔬菜产量影响不明显。     

Zeta Potential of Kaolinite in the Presence of Alkali,Alkaline Earth and Hydrolyzable Metal Ions

Electrokinetic remediation is one of the promising subsurface clean up techniques whose efficiency is directly affected by the zeta potential of clay minerals. To determine the factors affecting the zeta potential, in turn, electrokinetic remediation, the zeta potential of kaolinite is determined usingelectrophoretic mobility in the salt and heavy metals ions asfunctions of pH and concentration. The zeta potential of kaolinite ranged from -25 mV (pH 3) to -42 mV (pH 11) in water. The zeta potential of kaolinite became more negativewith increasing pH. The zeta potential of kaolinite was also found to be sensitive to the valence of ions. Results, furthermore, revealed that kaolinite has higher zeta potentialvalues in the presence of NaCl and LiCl than in water. However, the zeta potential of kaolinite decreased with divalent cationssuch as Ca²⁺ and Mg²⁺. The zeta potential of kaolinitewith heavy metal ions such as Cu²⁺, Co²⁺ and Pb²⁺ showed a similar trend, i.e., increase in the concentration ofthese ions caused a decrease in the zeta potential up to neutral pH, then it became positive. In highly basic environments, thezeta potential became negative again, giving two apparent pzcs. One of two apparent pzcs was attributed to kaolinite and the other one to the precipitation of these ions in highly basic solutions (pH ≥ 9).     

Removal of Fluoride from Water by Adsorption onto Lanthanum Oxide

Rare earth mineral based adsorbent viz. lanthanum oxide was investigated for potential application in defluoridation of drinking water for isolated and rural communities. Results of batch experiments indicated about 90% removal in 30 min from a 4 mg L⁻¹ synthetic fluoride solution. The effects of various parameters like contact time, pH, initial concentration, and sorbent dose on sorption efficiency were investigated. Adsorption efficiency was dependent on initial fluoride concentration and the sorption process followed BET model. Variation of pH up to 9.5 has insignificant effect on sorption and beyond a pH of 9.5, the effect was drastic. Among anions investigated, carbonates exhibited high detrimental effect on fluoride adsorption while anions like bicarbonates, chlorides, and sulfates did not seriously affect the process. Adsorbent showed negligible desorption of fluoride in distilled water. Alum was more effective regenerant than HCl and NaOH. Results of cyclic regeneration with alum indicated that the sorbent could be regenerated for ten cycles without significant loss of sorption capacity. Studies with upflow fixed-bed continuous flow columns indicated the usefulness of sorbent for fluoride removal in continuous flow process.     

Evaluation of Non-Conventional Coagulants to Remove Turbidity from Water

Coagulation and flocculation are basic chemical engineering operations employed to remove suspended solids from water. The growing concern for environmental and ecological issues warrants the use of the biodegradable flocculants in wastewater and industrial effluent treatment. In this work, unconventional coagulant, namely lactic acid, calcium lactate, sodium lactate, and citric acid were studied in comparison with AlCl₃, a usual coagulant widely employed to remove water turbidity. It was observed that lactic acid and calcium lactate were able to reduce the water turbidity similarly to AlCl₃. This fact can be very interesting because lactic acid salts can be produced by biotechnological process, and contrarily to aluminium salts, they are biodegradable, reducing the risk for human and animal’s health.     

Surface loading effect on Cd and Zn sorption by kaolinite and montmorillonite from low concentration solutions

Studies of Cd and Zn sorption using Na-saturated kaolinite and montmorillonite, and low metal solution concentrations similar to those found in the environment, showed that metal sorption affinity (measured by K _d values) decreased markedly with increasing surface metal loading for both layer silicates. For equilibrium solution concentrations <0.1 μmol L^?1 for Cd, and < 1 μmol L^?1 for Zn, both metals were sorbed with greater affinity by kaolinite than montmorillonite. These results were probably due to the higher proportion of weakly acidic edge sites present on kaolinite surfaces. In the case of Zn there was an affinity reversal for equilibrium solution concentrations > 1 μmol L^?1, which was attributed to the permanent charge sites of montmorillonite. Cadmium ions were sorbed, by kaolinite, with greater affinity than Zn for equilibrium solution concentrations between 0.3 to 1.5 μmol L^?1. This result was attributed to retention of these metal ions through electrostatic attraction by permanent charge sites present on the kaolinite used in this work. According of these results it seems that metal sorption by these layer silicates involves predominantly edge weak acid sites at lower surface coverages (higher affinity sites), and permanent charge sites at higher metal coverages (lower affinity sites). It was concluded that Cd and Zn sorption by those two layer silicates is greatly influenced by surface metal coverage, and results cannot be extrapolated from low to high surface coverages, and viceversa.     

连续解吸中离子强度对可变电荷土壤和高岭石体系pH的影响

研究了两种可变电荷土壤中在去离子水中和0.1 mol L-1 Na NO3溶液中吸附铜离子和钙离子后依次被浓度从低到高的Na NO3溶液连续解吸时,离子强度变化对每次解吸前后体系p H变化(Δp H)的影响,为了进一步了解其相关机理,作为对照,也研究了各种条件下,离子强度变化对高岭石Δp H的影响。结果表明,无论是否有吸附性二价阳离子的存在,或者吸附性阳离子属性(专性吸附型离子或电性吸附型离子)如何,当样品依次被去离子水、0.01 mol L-1 Na NO3、0.1 mol L-1 Na NO3以及1 mol L-1 Na NO3解吸时,在去离子水中和Na NO3溶液中的解吸过程对Δp H的影响截然不同。总体而言,如果解吸时体系离子强度趋于降低,Δp H将为正值,反之则为负值,且Δp H变幅开始增大时的起始点所对应的p H吸附基本相同,该起始点应该与高岭石ZPC(电荷零点)紧密相关。对上述结果的分析表明,解吸过程中,引起上述Δp H变化规律的根本原因之一是连续解吸过程中的离子强度变化导致的可变电荷表面的表面电位变化。