Assessment of environmental parameters effect on potentially toxic elements mobility in foreshore sediments to support marine-coastal contamination prediction.

Potentially toxic elements (PTEs) presence in marine sediments can significantly affect the environmental quality and negatively influence economy and recreational activities in related areas. Accordingly, contamination monitoring and control in the marine environment is a fundamental task. In this work, four PTEs behavior (i.e. As, Hg, Pb, and Zn) in sandy foreshore sediments (SFSs) was thoroughly investigated at different pH, redox potential and temperature conditions of the marine water. For all the tests, the released As was 2.7-6 times higher than its initial concentration in water. Nonetheless, final mass balances showed that preferential release in the liquid phase occurred for Pb and Hg (up to 10 % and 9.1 %, respectively). Moreover, final Zn and Hg content increase in SFSs labile fractions indicated their higher bioavailability after the tests. The obtained results outline an approach useful to predict the contaminants behavior in marine matrices and support environmental monitoring and preservation strategies.

Phosphorus recovery as struvite and hydroxyapatite from the liquid fraction of municipal sewage sludge with limited magnesium addition.

Phosphorus (P) is an essential element to produce feed and fertilizers but also a nonrenewable resource. Both the predicted exhaustion of phosphatic rocks and the risk of eutrophication lead to an increasing necessity for P recovery methodologies to be applied in municipal wastewater treatment plants (WWTPs). One of the most promising solutions involves the precipitation of P-based minerals reusable as slow-release fertilizers. In this study, P recovery as struvite and hydroxyapatite from a municipal WWTP digestate liquid fraction (centrate) was investigated at varying pH (8-10), reagent typologies (MgCl2 , NaOH, Ca(OH)2 , and CaCl2 ), and concentrations under limiting magnesium doses through liquid- and solid-phase analyses and thermodynamical modeling. A maximum P recovery of 87.3% was achieved at pH 9 by adding NaOH and MgCl2 at a dose of 656 mg/L (the higher tested). According to these data, it was estimated that 92.0 tons/year of struvite and 33.2 tons/year of hydroxyapatite could be recovered from the WWTP centrate with a cost for reagent consumption being almost 50% of the mean P market value. An increase in P precipitation was observed while comparing experiments with the same pH values but with a higher Mg2+ dose. Ca2+ addition led to extensive P precipitation but mainly as amorphous phases that interfere with struvite formation.

Characterising contaminants distribution in marine-coastal sediments through multivariate and nonparametric statistical analyses: a complementary strategy supporting environmental monitoring and control.

This work investigates a statistical approach analysing data from monitoring activities on marine-coastal areas for environmental quality determination and surveillance. Analyses were performed on a database of the Environmental Protection and Prevention Agency of the Puglia Region. As, Cr, Ni, and Pb concentration values in marine sediments and biota from 2013 to 2015 and 2017 were processed to investigate different contaminant characteristics. Hierarchical cluster analysis identified three contaminant distribution classes with (1) highest Cr, Ni, and Pb concentrations, (2) highest As concentration, and (3) lowest contaminants concentration. The Kruskal-Wallis and Friedman tests showed that contaminant distributions were statistically different when considering the monitoring years and classes. However, statistical similarities resulted during the 2013-2017 and 2014-2015 periods. Spearman's coefficients displayed positive correlations among the pollutants in each matrix and mainly negative correlations for matrices comparison. This methodology aims to provide a practical support for monitoring to identify potential environmental deterioration over time and correlations with specific contamination sources.

Phosphorous removal and recovery from urban wastewater: Current practices and new directions.

Phosphate rocks are an irreplaceable resource to produce fertilizers, but their availability will not be enough to meet the increasing demands of agriculture for food production. At the same time, the accumulation of phosphorous discharged by municipal wastewater treatment plants (WWTPs) is one of the main causes of eutrophication. In a perspective of circular economy, WWTPs play a key role in phosphorous management. Indeed, phosphorus removal and recovery from WWTPs can both reduce the occurrence of eutrophication and contribute to meeting the demand for phosphorus-based fertilizers. Phosphorous removal and recovery are interconnected phases in WWTP with the former generally involved in the mainstream treatment, while the latter on the side streams. Indeed, by reducing phosphorus concentration in the WWTP side streams, a further improvement of the overall phosphorus removal from the WWTP influent can be obtained. Many studies and patents have been recently focused on treatments and processes aimed at the removal and recovery of phosphorous from wastewater and sewage sludge. Notably, new advances on biological and material sciences are constantly put at the service of conventional or unconventional wastewater treatments to increase the phosphorous removal efficiency and/or reduce the treatment costs. Similarly, many studies have been devoted to the development of processes aimed at the recovery of phosphorus from wastewaters and sludge to produce fertilizers, and a wide range of recovery percentages is reported as a function of the different technologies applied (from 10-25% up to 70-90% of the phosphorous in the WWTP influent). In view of forthcoming and inevitable regulations on phosphorous removal and recovery from WWTP streams, this review summarizes the main recent advances in this field to provide the scientific and technical community with an updated and useful tool for choosing the best strategy to adopt during the design or upgrading of WWTPs.

Bioaugmentation strategy to enhance polycyclic aromatic hydrocarbons anaerobic biodegradation in contaminated soils.

This paper proposes an innovative bioaugmentation approach for the remediation of polycyclic aromatic hydrocarbon (PAH) contaminated soils, based on a novel habitat-based strategy. This approach was tested using two inocula (i-24 and i-96) previously enriched through an anaerobic digestion process on wheat straw. It relies on the application of allochthonous microorganisms characterized by specific functional roles obtained by mimicking a natural hydrolytic environment such as the rumen. The inocula efficiency was tested in presence of naphthalene alone, benzo[a]pyrene alone, and a mix of both of them. In single-contamination tests, i-24 inoculum showed the highest biodegradation rates (84.7% for naphthalene and 51.7% for benzo[a]pyrene). These values were almost 1.2 times higher than those obtained for both contaminants with i-96 inoculum and in the control test in presence of naphthalene alone, while they were 3 times higher compared to the control test in presence of benzo[a]pyrene alone. In mixed-contamination tests, i-96 inoculum showed final biodegradation efficiencies for naphthalene and benzo[a]pyrene between 1.1 and 1.5 higher than i-24 inoculum or autochthonous biomass. Total microbial abundances increased in the bioaugmented tests in line with the PAH degradation. The microbial community structure showed the highest diversity at the end of the experiment in almost all cases. Values of the Firmicutes active fraction up to 7 times lower were observed in the i-24 bioaugmented tests compared to i-96 and control tests. This study highlights a successful bioaugmentation strategy with biological components that can be reused in multiple processes supporting an integrated and environmentally sustainable bioremediation system.

A novel enrichment approach for anaerobic digestion of lignocellulosic biomass: Process performance enhancement through an inoculum habitat selection.

Inocula enrichment was performed using an innovative habitat-based selection approach to improve wheat straw (WS) anaerobic digestion (AD) efficiency. The procedure was carried out by sequentially re-inoculating the primary microbial community seven times in subsequent anaerobic reactors containing untreated WS. Re-inocula were performed at different re-inoculum times (24, 48, and 96 h) by moving a porous support mimicking a rumen structure from one batch to the next (S-tests) or re-inoculating only the culture medium (C-tests). Highest H2 production yields were observed after four and five re-inocula (0.08 ± 0.02 NmL h-1 gVS-1 and 0.09 ± 0.02 NmL h-1 gVS-1) for S-24 and S-48, respectively. For S-96, higher CH4 yields were observed after the start-up test and sixth re-inoculum (0.05 ± 0.003 NmL h-1 gVS-1 and 0.04 ± 0.005 NmL h-1 gVS-1, respectively). Accordingly, S-96 showed the highest active Archaea component (7%). C-test microbial communities were dominated by fermenting, hydrogen-producing bacteria and showed lower microbial community diversity than S-tests.

A simplified model to simulate bioaugmented anaerobic digestion of lignocellulosic biomass: Biogas production efficiency related to microbiological data.

Mathematical model applications for the bioaugmented anaerobic digestion (BAD) process seem to be lacking in the scientific literature, even more so when related to microbiological data. The present study suggests a simplified mathematical model to investigate and simulate the process kinetics of bioaugmented anaerobic digestion (BAD) aimed at improving biogas production from wheat straw (WS). Bioaugmented conditions were obtained through a mixed inoculum of anaerobic ruminal fungi (ARF) and hydrogen-producing fermenting bacteria (F210) added to a methanogenic inoculum. The investigation focused on two process configurations characterized by a mono (I-BAD) and two-stage (II-BAD) process and a conventional anaerobic digestion (AD) control test. Each configuration was used on two operating scales (i.e., 120 ml and 12,000 ml reactor volume) to provide different data sets for the calibration and validation of the mathematical model proposed. The model calibration step was used to determine the optimal values of selected parameters displaying higher significance for experimental result predictability. The model calibration results highlighted a similar behavior for both BAD tests, which was further strengthened by a statistical analysis supporting the observed correlation regardless of the BAD configuration involved. The BAD configuration always enhanced the CH4 production (>70%) with a faster kinetic in the II-BAD test. The microbiological results support the superior performance of the II-BAD test, displaying higher Archaea fractions (up to 14.5% on day 23) with values more than double compared to I-BAD and triple compared to the AD test. Furthermore, the presence of Methanosarcina inside the Archaea guild (6.4% and 4.5% at days 11 and 61, respectively) ensures a greater diversification of the metabolic pathways and supports the strength of the process performance. Cell density values are strongly in line with these results.

Optimization of Soil Washing to Reduce the Selenium Levels of Seleniferous Soil from Punjab, Northwestern India.

Seleniferous soil collected from the wheat ( L.)-grown agricultural land in Punjab, India, was characterized and the Se concentration in various soil fractions was determined by sequential extraction. The soil had a total Se content of 4.75 (±0.02) mg kg, of which 44% was observed in the oxidizable soil fraction. Soil flushing as an in situ technique was performed to simulate the Se migration pattern in case of rainfall or irrigation. Significant migration of Se from the upper layer to the lower layers was observed during water percolation through the soil column at a flow rate of 1 mL min, which could be attributed to Se reduction in the lower anoxic layers of the soil column. For ex situ treatment, the soil washing technique was optimized by varying different parameters such as treatment time, temperature, pH, liquid to solid (L:S) ratio, and presence of competing ions and oxidizing agents. Selenium extraction from soil was significantly improved by the presence of oxidizing agents in the washing solution: ∼38% Se was removed from the soil in the presence of 0.5% KMnO. In contrast, parameters such as treatment time, temperature, pH, L:S ratio, and competing ions did not significantly enhance the Se extraction efficiency. In this research, laboratory-scale in situ and ex situ treatment techniques for Se removal from soil were studied and optimized. The results provide an insight for large-scale Se removal and recovery from seleniferous soils.

Combined bioaugmentation with anaerobic ruminal fungi and fermentative bacteria to enhance biogas production from wheat straw and mushroom spent straw.

Bioaugmentation with anaerobic ruminal fungi and a pool of hydrogen-producing fermenting bacteria was tested on wheat straw (WS) and mushroom spent straw (MSS) with the aim of improving anaerobic digestion performance. Batch tests were set up to simulate a Bioaugmentation Anaerobic Digestion (BAD) treatment comparing single- (I-BAD) and two-stage (II-BAD) process configurations, at two reactor scales, 120 and 1200 ml (×10). In both cases, higher CH4 cumulative production was obtained in the II-BAD configuration on WS (65.1 ±â€¯8.9 Nml and 922 ±â€¯73.8 Nml respectively). The II-BADx10 tests allowed increasing CH4 production (≃290% and ≃330% on WS and MSS, respectively) when compared to the unaugmented condition. Final results highlighted the achievable advantages of the two stage configuration in terms of CH4 production enhancement. Microbial community investigations confirmed the efficiency of the bioaugmentation treatment and revealed that such a result was mainly related to the Methanosarcinales increase, mostly composed by Methanosaeta.

Ethylenediamine-N,N'-Disuccinic Acid (EDDS)-Enhanced Flushing Optimization for Contaminated Agricultural Soil Remediation and Assessment of Prospective Cu and Zn Transport.

This paper presents the results of an experimental study aimed at investigating the effect of operative parameters on the efficiency of a soil flushing process, conducted on real contaminated soil containing high amounts of Cu and Zn. Soil flushing tests were carried out with Ethylenediamine-N,N'-disuccinic acid (EDDS) as a flushing agent due to its high biodegradability and environmentally friendly characteristics. Process parameters such as Empty-Bed Contact Time (EBCT) and EDDS solution molarity were varied from 21-33 h and from 0.36-3.6 mM, respectively. Effects on the mobility of cations such as Fe and Mn were also investigated. Results showed that very high performances can be obtained at [EDDS] = 3.6 mM and EBCT = 33 h. In these conditions, in fact, the amount of removed Cu was 53%, and the amount of removed Zn was 46%. Metal distribution at different depths from the top surface revealed that Cu has higher mobility than Zn. The process results were strongly dependent on the exchange of metals due to the different stability constants of the EDDS complexes. Finally, results from a comparative study showed that soil washing treatment reached the same removal efficiency of the flushing process in a shorter time but required a larger amount of the EDDS solution.

Cigarette Smoking is Associated with Decreased Bone Gla-protein (BGP) Levels in Hemodialysis Patients.

BACKGROUND: Bone Gamma-carboxyglutamic acid (Gla)-protein (BGP or osteocalcin) is a vitamin K-dependent protein involved in the regulation of bone mineralization. Smoking is a risk factor for osteoporosis. METHODS: We carried out a secondary analysis of the Vitamin K Italian (VIKI) study to investigate the association between cigarette smoking and BGP levels in patients with end stage renal disease. Data were collected in 370 haemodialysis patients, 37% (136) smokers (or ex-smokers) and 63% (234) nonsmokers. Vascular calcifications and vertebral fractures (quantitative morphometry) were identified on spine radiographs. RESULTS: Smokers had significantly lower BGP levels (152 vs. 204 µg/L, p=0.003). Smokers had lower plasma phosphate levels (4.2 vs. 4.7 mg/dl, p<0.01). Lower BGP levels were associated with aortic calcification (p<0.001), iliac calcification (p=0.042) and vertebral fractures (p=0.023). In addition, the regression model showed that smoking is associated with a significant reduction of total BGP levels by about 18% (p=0.01). CONCLUSION: This is the first clinical study in a haemodialysis population, which identifies cigarette smoking as a potential factor that can lower BGP levels, a protective agent in bone and vascular health.

Investigation of different ethylenediamine-N,N'-disuccinic acid-enhanced washing configurations for remediation of a Cu-contaminated soil: process kinetics and efficiency comparison between single-stage and multi-stage configurations.

A comparison of Cu extraction yields for three different ethylenediamine-N,N'-disuccinic acid (EDDS)-enhanced washing configurations was performed on a Cu-contaminated soil. Batch experiments were used to simulate a single-stage continuous stirred tank reactor (CSTR) and a multi-stage (side feeding and counter-current) reactor. Single-stage CSTR conditions were simulated for various EDDS:(Cu + Cd + Pb + Co + Ni + Zn) molar ratio (EDDS:M ratio) (from 1 to 30) and liquid to soil (L/S) ratio (from 15 to 45). The highest Cu extraction yield (≃56%) was achieved with EDDS:M = 30. In contrast, a Cu extraction yield decrease was observed with increasing L/S ratio with highest extracted Cu achievement (≃48%) for L/S = 15. Side feeding configuration was tested in four experimental conditions through different fractionation mode of EDDS dose and treatment time at each washing step. Results from the four tests showed all enhanced Cu extraction (maximum values from ≃43 to ≃51%) achieved at lower treatment time and lower EDDS:M molar ratio compared to CSTR configuration with L/S = 25 and EDDS:M = 10. The counter-current washing was carried out through two washing flows achieving a process performance enhancement with 27% increase of extracted Cu compared to single-stage CSTR configuration. Higher Cu extraction percentage (36.8%) was observed in the first washing phase than in the second one (24.7%).

Application of an electrochemical treatment for EDDS soil washing solution regeneration and reuse in a multi-step soil washing process: Case of a Cu contaminated soil.

Soil washing is an extensively used process for remediation of heavy metals contaminated soils. However the amount of fresh washing solution to be used represents a significant economical drawback of this process. This paper investigates the application of an electrochemical process (Fe/Fe electrodes couple) for the regeneration of a spent EDDS solution, containing Cu and major competitor cations (Ca, Fe, Mg, and Mn). The effect of current density, pH and conductivity of the washing solution on the recovery process performances was investigated. Current density showed the highest influence on Cu, Mg and Mn removal yields. Maximum removal yields reached 99% for Cu, 77% for Mn and 49% for Mg. No influence of the investigated parameters on Ca removal was observed, while an increase of Fe concentration due to anode dissolution occurred. Characterization of sludge produced from the 2 h electrochemical test (5 mA cm(-2), pH = 8, 8 mS cm(-1)) displayed concentrations of 2.8 g kg(-1) for Ca, 0.4 g kg(-1) for Cu, 535.6 g kg(-1) for Fe, 2.6 g kg(-1) for Mg. TCLP tests at pH 2.88 and 4.93 showed a low leaching percentage (Ca, 10-21%; Cu, 6-12%; Fe, 0.22% Mg, 27-36%). Multi-washing tests were carried out to assess the decrease of the chelating ability of the regenerated washing solution and the Cu extraction efficiency.

Transplant renal artery stenosis in children: risk factors and outcome after endovascular treatment.

BACKGROUND: Transplant renal artery stenosis (TRAS) is an increasingly recognised cause of post-transplant hypertension. METHODS: We retrospectively analysed 216 paediatric renal recipients transplanted between 2001 and 2011 to assess TRAS prevalence and percutaneous transluminal angioplasty (PTA) efficacy. To assess risk factors, we compared children with TRAS with a propensity score-matched cohort of recipients without TRAS. RESULTS: Of the 216 paediatric patients who were transplanted in the study period, 44 were hypertensive (prevalence 20.3 %) and ten presented with TRAS (prevalence 4.6 %, median age at transplantation 14 years, range 6.78-17.36 years). Hypertensive patients without TRAS were prescribed one to two anti-hypertensive agents, whereas patients with TRAS required one to five medications. In the TRAS group, one recipient presented with vascular complications during surgery, and in three patients the graft had vascular abnormalities. TRAS was detected by Doppler ultrasonography (US) performed due to hypertension in nine of the patients with TRAS, but in the tenth case the TRAS was clinically silent and detected by routine Doppler-US screening. TRAS diagnosis was refined using angio-computed tomography or angio-magnetic resonance imaging. All patients underwent PTA without complications. Significant improvement after PTA was observed in the standard deviation scores for blood pressure [3.2 ± 1.4 (pre-PTA) vs. 1.04 ± 0.8 (post-PTA); p = 0.0006) and graft function [creatinine clearance: 69 ± 17.08 (pre-PTA) vs. 80.7 ± 21.5 ml/min/1.73 m(2) (post-PTA); p = 0.006] We observed no significant differences between the two cohorts for cold ischaemia time, recipient/donor weight ratio, delayed graft function, cytomegalovirus infections and acute rejection episodes. CONCLUSIONS: Our study reports a low but significant TRAS prevalence among the paediatric patients who were transplanted at our centre in the study period and confirms that PTA is an effective and safe therapeutic option in paediatric renal transplant recipients. Known risk factors do not appear to be related to the development of TRAS.

Relationship between plasma phospholipid polyunsaturated fatty acid composition and bone disease in renal transplantation.

To investigate the relationship between polyunsaturated fatty acid (PUFA) and bone metabolism in renal transplant patients, plasma phospholipid (PP) PUFA levels, biochemical markers of bone turnover and bone mineral density (BMD) were determined in 22 recipients of a first renal allograft at baseline and after a mean 24.4 month follow-up. A significant increase in PP n-3 PUFA content, in the [n-3 PUFA/ arachidonic acid] ratio and in BMD values was observed, as well as a close correlation between the increase in PP n-3 PUFA content and femoral neck BMD. Multivariate regression analysis showed that BMD improvement was positively related to PP n-3 PUFA variation and baseline PP eicosapentaenoic acid levels, and negatively to PP arachidonic acid modification. Tacrolimus- versus cyclosporine-treated patients demonstrated a significant increase in femoral neck BMD and PP n-3 PUFA content. This is the first longitudinal study showing a link between PP-PUFA composition and bone disease in renal transplantation.