The biomass characteristics, the process performance, and the microbial community for a sequencing batch reactor (SBR) and a submerged membrane SBR (MSBR) were evaluated. A synthetic wastewater containing only 4-chlorophenol (4CP) was used as the sole source of carbon and energy. Degradation efficiencies of 4CP were higher than 99% for both reactors, and no significant differences on the 4CP degradation rates were observed for the SBR (116.9 ± 0.9 mg 4CP g VSS−1 h−1) as well as for the MSBR (117.3 ± 0.5 mg 4CP g VSS−1 h−1). Despite the similar results obtained for the physicochemical parameters, it was found that the biomass characteristics were different considering the sludge volumetric index, settling velocity, protein content in the mixer liquor, and total suspended solids in the effluent. The settling velocity was three times higher in the SBR than in the MSBR; however, a better quality, considering suspended solids, was observed for the MSBR. The protein concentration in the mixed liquor was higher in the MSBR than in the SBR, generating foaming problems in the MSBR. A similarity analysis was made with the Ochiai–Barkman index. Even though the reactors were inoculated with the same biomass, significant differences in the composition and populations dynamics were observed.

Conifer forests in the Jizerské Mountains, Czech Republic have experienced widespread and long-lasting effects related to industrial SO₂ pollution. To explore the spatial and temporal impact of this phenomenon on Norway spruce stands, a transect of sites was sampled to the southeast of the Polish coal-fired power station Turów. Tree growth at all sites displayed a significant reduction around 1980, which could not be explained by climate alone. However, by incorporating both climate and SO₂ variables in multiple regression models, the chronology trends could be explained well. The lowest growth rates were found to coincide with the period of greatest atmospheric SO₂ concentrations and the degree of suppression decreased with increasing distance from the power station. The period of growth suppression in a Silver fir site appeared to be more severe and longer in duration than for the spruce, although differing site conditions prevented a direct comparison. Fir trees also appeared to be affected by SO₂ pollution earlier in the twentieth century compared to spruce. Growth of both species, however, did not return to predicted levels following the reduction of pollution levels in the 1990s. A comparison with spruce and fir data from the Bavarian Forest, a region also affected by pollution in the past, revealed a temporal difference in growth suppression, likely related to different timings and loadings of SO₂ emissions between both regions. This study highlights pollution as another potential causal factor for the ‘divergence problem’ and dendroclimatic reconstructions in polluted regions should be developed with caution.

Water quantity and quality were monitored for 3 years in a 360-m-long wetland with riparian fences and plants in a pastoral dairy farming catchment. Concentrations of total nitrogen (TN), total phosphorus (TP) and Escherichia coli were 210–75,200 g N m−3, 12–58,200 g P m−3 and 2–20,000 most probable number (MPN)/100 ml, respectively. Average retentions (±standard error) for the wetland over 3 years were 5 ± 1%, 93 ± 13% and 65 ± 9% for TN, TP and E. coli, respectively. Retentions for nitrate–N, ammonium–N, filterable reactive P and particulate C were respectively −29 ± 5%, 32 ± 10%, −53 ± 24% and 96 ± 19%. Aerobic conditions within the wetland supported nitrification but not denitrification and it is likely that there was a high conversion rate from dissolved inputs of N and P in groundwater, to particulate N and P and refractory dissolved forms in the wetland. The wetland was notable for its capacity to promote the formation of particulate forms and retain them or to provide conditions suitable for retention (e.g. binding of phosphate to cations). Nitrogen retention was generally low because about 60% was in dissolved forms (DON and NOX–N) that were not readily trapped or removed. Specific yields for N, P and E. coli were c. 10–11 kg N ha−1 year−1, 0.2 kg P ha−1 year−1 and ≤109 MPN ha−1 year−1, respectively, and generally much less than ranges for typical dairy pasture catchments in New Zealand. Further mitigation of catchment runoff losses might be achieved if the upland wetland was coupled with a downslope wetland in which anoxic conditions would promote denitrification.

Current non-invasive biomonitoring techniques to measure heavy metal exposure in free ranging birds using eggs, feathers and guano are problematic because essential metals copper (Cu) and zinc (Zn) deposited in eggs and feathers are under physiological control, feathers accumulate metals from surface contamination and guano may contain faecal metals of mixed bioavailability. This paper reports a new technique of measuring lead (Pb), Cu and Zn in avian urate spheres (AUS), the solid component of avian urine. These metal levels in AUS (theoretically representing the level of metal taken into the bloodstream, i.e. bioavailable to birds) were compared with levels in eggs (yolk and shell), feathers and whole guano from chickens (Gallus gallus domesticus) exposed to a heavy metal-contaminated soil (an allotment soil containing Pb 555 mg kg⁻¹ dry mass (dm), Cu 273 mg kg⁻¹ dm and Zn 827 mg kg⁻¹ dm). The median metal levels (n = 2) in AUS from chickens exposed to this contaminated soil were Pb 208 μg g⁻¹ uric acid, Cu 66 μg g⁻¹ uric acid and Zn: 526 μg g⁻¹ uric acid. Lead concentrations in egg yolk and shell samples (n = 3) were below the limit of detection (<2 mg kg⁻¹), while Cu and Zn were only consistently detected in the yolk, with median values of 3 and 70 mg kg⁻¹ (dm), respectively, restricting the usefulness of eggs as a biomonitor. Feathers (n = 4) had median Pb, Cu and Zn levels respectively of 15, 10 and 140 mg kg⁻¹ (dm), while whole guano samples (n = 6) were 140, 70 and 230 mg kg⁻¹ (dm). Control samples were collected from another chicken flock; however, because they had no access to soil and their diet was significantly higher in Cu and Zn, no meaningful comparison was possible. Six months after site remediation, by top soil replacement, the exposed chickens had median Pb, Cu and Zn levels respectively in whole guano (n = 6) of 30, 20 and 103 mg kg⁻¹ (dm) and in AUS (n = 4) of 147, 16 and 85 μg g⁻¹ uric acid. We suggest the persistent high Pb level in AUS was a consequence of bone mobilised for egg production, releasing chronically sequestered Pb deposits into the bloodstream. In contrast, AUS levels of Cu and Zn (metals under homeostatic control and sparingly stored) had declined, reflecting the lower current exposure. However because pre- and post-remediation samples were measured using different methods carried out at different laboratories, such comparisons should be guarded. The present study showed that metals can be measured in AUS, but no assessment could be made of availability or uptake to the birds because tissue and blood samples were not concomitantly analysed. A major short coming of the study was the inappropriate control group, having no access to uncontaminated soil and being fed a different diet to the exposed birds. Furthermore guano and urine analysis should have been carried out on samples from individual birds, so biological (rather than just technical) variation of metal levels could have been determined. Future studies into using AUS for biomonitoring environmental heavy metals must resolve such experimental design issues.

Copper oxide nanoparticles were immobilized on quartz sand and their catalytic activity for the degradation of an organic dye was investigated. The use of nanoparticles as catalysts for non photo-induced oxidation of water contaminants is relatively new. The CuO catalyst has shown promising results when suspended in free form in batch systems. Because heterogeneous catalysis is often the preferred mode of operation for application of catalytic technology, we studied the effect of immobilization of the nanoparticles on quartz sand in a flow-through system and its implication for the catalytic process. The coated sand was packed in a column and its catalytic activity for the degradation of an organic dye was investigated in a series of flow-through experiments with hydrogen peroxide as the oxidant. Control experiments with uncoated sand were also performed for comparison. The coated sand demonstrated high catalytic ability, achieving complete oxidation of the dye. During the reaction, CO2 was produced, leading to a decrease in the water saturation in the column and reduced contact surface between the nano-CuO catalysts and the dye solution. The degradation was improved by enabling a longer residence time of the dye in the column, yielding up to 85% degradation of the dye. These results suggest that CuO nanoparticle-coated sand is an efficient catalyst for complete degradation of the organic dye.

Frequently, sulfonamide antibiotic agents reach arable soils via excreta of medicated livestock. In this study, accumulation and phytotoxicity indicators were analyzed to evaluate the effects of sulfonamides on plants. In a greenhouse experiment, willow (Salix fragilis L.) and maize (Zea mays L.) plants were grown for 40 days in soil spiked with 10 and 200 mg kg⁻¹ sulfadiazine (SDZ). Distribution of SDZ and major metabolites among bulk and rhizosphere soil, roots, leaves, and stems was determined using accelerated solvent extraction and LC − MS/MS analysis. Accumulation of SDZ was stronger in willow. The antibiotic was mainly stored inside roots and 4-hydroxy-sulfadiazine presence increased with the administered SDZ concentration. SDZ altered root geotropism, increased the lateral root number, and affected plant water uptake. The high concentration caused serious stress in willow (e.g., reduced C/N ratio and total chlorophyll content) and the death of maize plants. Even at environmentally relevant soil concentrations (10 mg kg⁻¹), SDZ exhibited adverse effects on root growth, while at artificially high concentrations (200 mg kg⁻¹), it showed a strong potential to impair plant performance and biomass. Willow, a fast growing tree species, showed potential for possible phytoremediation purposes.

Soil aquifer treatment (SAT) is a cost-effective natural wastewater treatment and reuse technology. It is an environmentally friendly technology that does not require chemical usage and is applicable to both developing and developed countries. However, the presence of organic matter, nutrients, and pathogens poses a major health threat to the population exposed to partially treated wastewater or reclaimed water through SAT. Laboratory-based soil column and batch experiments simulating SAT were conducted to examine the influence of temperature variation and oxidation–reduction (redox) conditions on removal of bulk organic matter, nutrients, and indicator microorganisms using primary effluent. While an average dissolved organic carbon (DOC) removal of 17.7 % was achieved in soil columns at 5 °C, removal at higher temperatures increased by 10 % increments with increase in temperature by 5 °C over the range of 15 to 25 °C. Furthermore, soil column and batch experiments conducted under different redox conditions revealed higher DOC removal in aerobic (oxic) experiments compared to anoxic experiments. Aerobic soil columns exhibited DOC removal 15 % higher than that achieved in the anoxic columns, while aerobic batch showed DOC removal 7.8 % higher than the corresponding anoxic batch experiments. Ammonium-nitrogen removal greater than 99 % was observed at 20 and 25 °C, while 89.7 % was removed at 15 °C, but the removal substantially decreased to 8.8 % at 5 °C. While ammonium-nitrogen was attenuated by 99.9 % in aerobic batch reactors carried out at room temperature, anoxic experiments under similar conditions revealed 12.1 % ammonium-nitrogen reduction, corresponding to increase in nitrate-nitrogen and decrease in sulfate concentration.

Lead forms stable compounds with phosphate and the immobilized Pb becomes less available to soil biota. In this study, we tested the bioavailabilty of Pb using earthworms (Eisenia fetida) and plants after immobilization of Pb by a soluble P compound and an insoluble rock phosphate compound in the presence of phosphate-solubilizing bacteria (Enterobacter sp.). Rock phosphate in the presence of phosphate-solubilizing bacteria and a soluble P compound enhanced Pb immobilization as measured by NH4NO3-extractable Pb concentration, thereby reduced its bioavailability as evaluated by earthworm Pb loading and sunflower (Helianthus annuus) Pb uptake under greenhouse conditions. However, soluble P treatment increased the concentration of Pb in soil solution thereby inhibited the root elongation of mustard (Brassica hirta) seedlings. Sunflower plants in the Pb-spiked soil without P amendments showed symptoms of necrosis and stunting because of Pb toxicity. Both soluble and insoluble P treatments significantly increased shoot and root weight and decreased Pb concentration in shoot by more than 50% compared to the control. However, high Pb concentration in soil solution was found in soluble P treatment, which can be attributed to dissolved organic carbon–Pb complex formation, thereby increasing Pb mobility. The inoculation of phosphate-solubilizing bacteria can facilitate phytostabilization of Pb-contaminated site.

Soil pollution with heavy metals is a worldwide environmental problem. Phytoremediation through phytoextraction and phytostabilization appears to be a promising technology for the remediation of polluted soils. It is important to strongly emphasize that the ultimate goal of a heavy metal remediation process must be not only to remove the heavy metals from the soil (or instead to reduce their bioavailability and mobility) but also to restore soil quality. Soil quality is defined as the capacity of a given soil to perform its functions. Soil microbial properties are increasingly being used as biological indicators of soil quality due to their quick response, high sensitivity, and, above all, capacity to provide information that integrates many environmental factors. Indeed, microbial properties are among the most ecologically relevant indicators of soil quality. Consequently, microbial monitoring of the recovery of soil quality is often carried out during heavy metal phytoremediation processes. However, soil microbial properties are highly context dependent and difficult to interpret. For a better interpretation of microbial properties as indicators of soil quality, they may be grouped within categories of higher ecological relevance, such as soil functions, ecosystem health attributes, and ecosystem services.

A central wastewater treatment facility was built in 1997 for the town of Suwannee that eliminated 850 inadequately operating on-site sewage treatment and disposal systems. During a study in 1989–1990, Salmonella were detected in Suwannee River water samples upstream and downstream of the town of Suwannee. This study presents the findings of fecal coliform distribution between the years 1996 and 2009 in canals and the main stem of Suwannee River near the town of Suwannee, a coastal area in southeastern USA. Fecal coliforms were measured and assessed to evaluate the water quality before and after the installation of the central wastewater treatment facility. In the canals nearby the town of Suwannee, significant differences in fecal coliform concentrations were detected between the samples collected before and after the operation of the central wastewater treatment facility. Average fecal coliform of 537 most probable number (MPN)/100 ml in the canals in 1996 was reduced to 218 MPN/100 ml after the operation of wastewater treatment facility. The fecal coliform levels in canals decreased significantly in the last 13 years. Even though the average fecal coliform levels in the river was reduced from 170 to 86 MPN/100 ml before and after the installation of the wastewater treatment facility, respectively, the difference was not statistically significant.