Competitive sorption of linear alkylbenzene sulfonate (LAS) surfactants and the antibiotics sulfamethoxazole and ciprofloxacin in wastewater-irrigated soils of the Mezquital Valley,Mexico

Purpose

The increasing reuse of wastewater for irrigation introduces surfactants and antibiotics into the environment. How these two kinds of compounds interact with regard to their sorption processes in soil is not clear.

Materials and methods

We performed batch experiments to investigate the sorption of linear alkylbenzene sulfonates (LAS) and its effect on sorption of sulfamethoxazole and ciprofloxacin in irrigated and non-irrigated soils with different organic matter (OM) contents.

Results and discussion

LAS sorption was non-linear in the presence of the antibiotics, and as general trend, it increased with rising OM content of soils. Free LAS was also removed from solution by complexation with Ca²⁺. Dissolved organic compounds released from soils with OM contents ≥18.4 g kg^?1 further reduced LAS sorption. Sorption of sulfamethoxazole was reduced by LAS sorption only in one soil with a small OM content of 9.5 g kg^?1.

Conclusions

The strong sorption of ciprofloxacin is not affected by LAS. Sulfamethoxazole sorption only competes with LAS sorption in organic matter-poor soils. Accumulation of organic matter in soils, for example due to long-term wastewater irrigation, provides extra sorption capacity for LAS and sulfamethoxazole so that competition for sorption sites is reduced.

     

Kinetics and binding capacity of six soils for structurally defined hydrolyzable and condensed tannins and related phenols

Purpose  

We investigated tannin–soil interactions by assessing the kinetics of sorption and sorption capacities, and their relationship to the chemical properties of six polyphenolic compounds and the textures of six soils. We developed a new extraction procedure for recovering tannins from soil samples by successive extraction with solvents of decreasing polarity.     

Degradation and sorption of commonly detected PPCPs in wetland sediments under aerobic and anaerobic conditions

Purpose

Wetlands are a popular tool to treat/polish wastewater by reducing nutrient loading into the environment. In addition to nutrients, organic contaminants, such as pharmaceuticals and personal care products (PPCPs), are commonly detected in treated wastewater. Treatment wetlands may reduce concentrations of PPCPs before the treated effluent enters rivers and streams. Oxygen status may greatly affect the attenuation of PPCPs in wetland sediments by influencing microbial makeup and activity. An understanding of the effect of redox conditions on the degradation of PPCPs and the factors influencing PPCP sorption to wetland sediments is needed to maximize PPCP removal in treatment wetlands.

Materials and methods

Three wetland sediments from the San Diego Creek and Newport Bay watershed in Southern California, USA, were incubated under aerobic and anaerobic conditions to assess the degradation of several regularly occurring PPCPs and their phase distribution as a function of time.

Results and discussion

Under aerobic conditions, ibuprofen, N,N-diethyl-meta-toluamide (DEET), and gemfibrozil generally had half-life values around 20?days, while the half-life of carbamazepine was substantially longer (between 165 and 264?days). The anaerobic half-lives of gemfibrozil and ibuprofen increased by factors of 11?C34 and carbamazepine increased by factors of 1.5?C2.5. There was no detectable anaerobic degradation of DEET. The apparent phase distribution coefficient increased over time for DEET, carbamazepine and gemfibrozil, indicating that sorption of PPCPs to wetland sediments may be more limited than that predicted using equilibrium sorption coefficient values.

Conclusions

Knowledge of the capacity of wetland sediments for degrading and sorbing PPCPs is vital to the design of treatment wetlands. Degradation of the selected PPCPs was enhanced under aerobic conditions as compared to anaerobic conditions. Sorption to sediments increased with contact time, indicating that longer hydraulic retention will increase wetland capabilities for removing PPCPs.     

Sorption of the herbicide terbuthylazine in two New Zealand forest soils amended with biosolids and biochars

Background, aim, and scope  

Terbuthylazine is one of the most commonly used herbicides for vegetation management in forest plantations in New Zealand. Knowledge about the sorption of terbuthylazine on forest soils, especially the influence of coexisting organic amendments, remains obscure. In this study, we evaluated the effects of biosolids and biochars on the sorption of terbuthylazine to forest soils.     

Enhanced sorption of polycyclic aromatic hydrocarbons by soil amended with biochar

Purpose  

Polycyclic aromatic hydrocarbon (PAHs) are ubiquitous pollutants in agricultural soils in China. Biochar is the charred product of biomass pyrolysis, which is widely applied to soils to sequestrate atmospheric carbon dioxide and guarantees a long-term benefit for soil fertility. Knowledge about the impacts of various biochars on soil sorption affinity remains obscure. In this study, we evaluated the effects of various biochars on PAHs sorption to biochar-amended agricultural soil.     

Organic and inorganic phosphate interactions with soil hydroxy-interlayered minerals

Background  

Even though extensive work has been done on P interactions with free Al- and Fe-hydroxide minerals, limited or no information exists on sorption/desorption processes of organic and inorganic phosphate forms with soil hydroxy-interlayered minerals.     

Influence of incubation time on phosphorus sorption dynamics in lake sediments

Purpose  

Estimating phosphorus (P) sorption is generally achieved by measuring a decrease in P concentration over a defined period. However, information within the literature has not been able to be widely applied, probably due to the variability in incubation periods and initial P concentrations in reported experiments. The objective of this study was to investigate whether variations in incubation time and initial P concentration might result in differences in measured levels of P sorption in sediments.     

Sorption of perfluorinated compounds from contaminated water to activated carbon

Introduction  

Perfluorinated compounds (PFC) are toxic and bioaccumulative compounds that are ubiquitous in the environment. It is important to develop effective techniques to remove PFC from water. This study is the first to investigate sorption of PFC to activated carbon (AC) at environmentally relevant nanogram per liter concentrations.     

Sorption and genotoxicity of sediment-associated pentachlorophenol and pyrene influenced by crop residue ash

Purpose  

The bioavailability and potential toxicity of sediment-associated organic compounds are affected by sorption processes. The particulate matter (ash) from field burning of crop residues is one of the primary sources for environmental black carbon, which is regarded as supersorbent for organic contaminants and may reduce their ecotoxicity. This study aimed to investigate the influence of ash on sediment-associated organic pollutants’ potential toxicity.     

Effect of soil components on the surfactant-enhanced soil sorption of PAHs

Purpose  

The use of cationic surfactants was proposed to enhance the soil retention of hydrophobic organic contaminants (HOCs). However, due to the complexity of soil composition, the effect of cationic surfactants on the soil sorption of HOCs was limited to a qualitative understanding. To gain further insight into the mechanism of the surfactant and predict its efficiency, a comparative study on the HOCs sorption capacities of the surfactants sorbed on pure typical soil components was investigated.     

Sorption of estrogens,triclosan, and caffeine in a sandy loam and a silt loam soil

Purpose  

Recently, pharmaceuticals and personal care products (PPCPs) have been identified in the environment. Concerns on the occurrence and fate of these compounds in soil and sediment have significantly increased. It is believed that these PPCPs sorb to soil and sediment; however, information on sorption of PPCPs is still limited. In this study, the sorption of estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethynylestradiol (EE2), triclosan, and caffeine to two loam soils and Ottawa sand was assessed.     

Estimation of water dynamics in a vertical-flow constructed wetland with a growing plant species

Purpose  

Vertical-flow constructed wetland (VFCW) is a promising technique for wastewater treatment comparable to conventional wastewater treatment plants. The physical, chemical, and biological processes and interactions in a VFCW are highly coupled with water movement, and thus the performance of a VFCW to remove contaminants hinges on a better understanding of its water dynamics. The aim of this study was to develop a model for estimating water dynamics in an artificial VFCW with a growing plant system.     

Lability and sorption of heavy metals as related to chemical,physical, and mineralogical characteristics of highly weathered soils

Purpose  

Heavy metal lability, probably, is the most important isolated factor to cause toxicity in plants and organisms in soils. Sorption of heavy metals, in turn, affects directly the amount of their labile forms in soils. Therefore, to assess sorption and quantify labile forms of Cd, Cu, Ni, Pb, and Zn, adsorption and incubation studies were carried out.     

Nitrogen use efficiency of microalgae application in wheat compared to mineral fertilizer

Background

Wastewater from sewage treatment plants contains high levels of nutrients, which can be used for plant nutrition. Classical wastewater treatment plants use complex microbial consortia of autotrophic and heterotrophic microorganisms for biological wastewater treatment. Certain autotrophic microalgae (e.g., species of the genera Chlorella, Scenedesmus, and Pediastrum) accumulate nutrients from wastewater very effectively.

Aims

We investigated the potential of microalgae biomass obtained from a prototype wastewater treatment plant as a source of nutrients for crops, focusing on nitrogen.

Methods

We provided wheat plants with different levels of algae biomass equivalent to 60, 120, and 180 kg N per hectare or with mineral fertilizer (N, P, and K) equivalent to the amounts contained in the algal biomass. Physiological and phenotypic traits were measured during growth, including vegetation indices, photosynthetic performance, growth, and nitrogen use efficiency (NUE). In addition, the adundances of Bacteria, Archaea and fungi and genes of ammonium oxidizing Bacteria and Archaea were determined in the rhizosphere of differently fertilized plants.

Results

Microalgal application at fertilizer levels of 120 and 180 kg N ha^–1 showed significantly improved physiological performance, growth, yield and nutrient uptake compared to the unfertilized control. Nevertheless, their yields and NUE were lower than with the application of equal amounts of mineral fertilization, while the adundance of rhizosphere microbes and ammonia-oxidizing microorganisms were not significantly affected.

Conclusions

Microalgae from wastewater treatments form a suitable source of organic fertilizer for wheat plants with only moderate reductions in N use efficiency compared to mineral fertilizer.     

Oxidation behavior and kinetics of sulfide by synthesized manganese oxide minerals

Purpose  

Sulfur is distributed widely in soils and sediments. Sulfide oxidation causes acid mine wastewater, toxicity, and corrosion. Manganese oxide minerals usually affect the migration, transformation, and fate of sulfur. To understand the oxidation behaviors of S²⁻ and influence factors, reaction process and kinetics were investigated by using different manganese oxides.     

Differences in sorption behavior of the herbicide 4-chloro-2-methylphenoxyacetic acid on artificial soils as a function of soil pre-aging

Purpose

The sorption behavior of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) to three different artificial soil mixtures was investigated. Artificial soils serve as model systems for improving understanding of sorption phenomena.

Materials and methods

The soils consisted of quartz, ferrihydrite, illite, montmorillonite, and charcoal. In a previous study, several selected mixtures had been inoculated with organic matter, and microbial aging (incubation) had been performed for different periods of time (3, 12, and 18?months) before conducting the sorption experiments. The effect of this pre-incubation time on the sorption behavior was determined. Interaction of MCPA with soil surfaces was monitored by aqueous phase sorption experiments, using high-performance liquid chromatography/ultraviolet and in selected cases Fourier-transformed infrared spectroscopy.

Results and discussion

The sorption behavior showed large differences between differently aged soils; Freundlich and linear sorption model fits (with sorption constants K _f , 1/n exponents, and K _d values, respectively) were given for pH?=?3 and the unbuffered pH of ??7. The largest extent of sorption from diluted solutions was found on the surfaces with a pre-incubation time of 3?months. Sorption increased at acidic pH values.

Conclusions

Regarding the influence of aging of artificial soils, the following conclusions were drawn: young artificial soils exhibit stronger sorption at lower concentrations, with a larger K _f value than aged soils. A correlation with organic carbon content was not confirmed. Thus, the sorption characteristics of the soils are more influenced by the aging of the organic carbon than by the organic carbon content itself.     

Evaluation of the Fate of Ciprofloxacin and Amoxicillin in Domestic Wastewater

The main objective of this study was to evaluate the contribution of sorption to the removal of two commonly used antibiotics (amoxicillin and ciprofloxacin) from wastewater. These antibiotics are excreted in large quantities with more than 75% of them being unmetabolized and are therefore likely to end up in domestic wastewater in significant quantities. The specific objectives were to determine the sorption behavior in synthetic wastewater (SWW), the effect of pH and contribution of microbial surfaces, to the sorption of these antibiotics. The SWW, adjusted to various pH levels, was used and sorption kinetics conducted at 100 and 250 ??g L^?1 concentrations. Adsorption isotherms were determined at different pH levels. The SWW (pH 6.6) was inoculated with Rhodococcus sp. B30 strain to determine the contribution of microbial surfaces to sorption. Generally, both antibiotics revealed a decrease in sorption with pH increase, suggesting that lowering the solution pH of the wastewater may reduce their amounts in wastewater solution. Comparatively, ciprofloxacin exhibited higher sorption than amoxicillin. The sorption distribution coefficient (K _d) values for ciprofloxacin ranged from 0.4356 to 0.8902 L?g^?1, with pH?=?5.5 exhibiting the highest K _d, while that for amoxicillin ranged from 0.1582 to 0.3858 L?g^?1 with the highest K _d at pH?=?3.5. There was a significant difference (p?<?0.05) in K _d values between various pH levels for both antibiotics except between the pH of 5.5 and 6.6. Both antibiotics were not degraded within 48 h by Rhodococcus sp. B30 strain. These results indicate that degradation may not be the major process of removal of compounds from wastewater treatment plants and hence the importance of sorption as an intervention technique.     

Adsorption kinetics of 17α-ethinyl estradiol and bisphenol A on carbon nanomaterials. II. Concentration-dependence

Purpose  

Carbon nanomaterials (CNMs) have attracted a great deal of research interest for their potential environmental applications because of their unique properties. Adsorption of organic chemicals on CNMs was reported to be important in controlling their environmental risks. However, the kinetics of the adsorption is hardly investigated in literature. The objective of this work was, therefore, to quantitatively describe the sorption kinetics of 17 α-ethinyl estradiol (EE2) and bisphenol A (BPA) on CNMs as compared to activated carbon (AC).     

Sorption isotherms and kinetics of Sb(V) on several Chinese soils with different physicochemical properties

Purpose

Sorption of antimony on soils is the primary factor that influences its immobilization and migration in the environment. In the present study, the sorption of Sb(V) onto seven Chinese soils with different physicochemical properties was investigated for exploring the relationship between the sorption capacity of Sb(V) and the physicochemical properties of the soils.

Materials and methods

Sorption isotherms and kinetics experiments were performed to ascertain the sorption capacity and the kinetic rate, respectively. The relationship between the sorption capacity of Sb(V) and the physicochemical properties of the soils was analyzed by multiple linear regressions.

Results and discussion

The results showed that the sorption isotherms fitted with both the Langmuir and Freundlich equations very well (R ²?=?0.936–0.997), and the sorption kinetic of Sb(V) onto the seven Chinese soils followed a pseudo-second-order reaction. The maximum sorption capacity of Sb(V) on the soils ranged from 134 to 1,333 mg?kg^?1. Nearly 94 % of the variability in maximum sorption of Sb(V) modeled by Freundlich equation could be described by Fe_DCB (dithionite–citrate–bicarbonicum extractable), and nearly 98 % of the variability could be described by Fe_DCB and Al_DCB.

Conclusions

Multiple linear regressions can be successfully applied to analyzing the relationship between sorption capacity and soil properties. Fe_DCB and Al_DCB played important roles in Sb(V) sorption onto soils. It would be useful to understand the environmental behaviors of Sb and for the implementation of risk assessment management and remediation strategies of Sb.     

Rural wastewater irrigation and nitrogen removal by the paddy wetland system in the Tai Lake region of China

Background, aim, and scope  

A large area of water eutrophication in the Tai Lake region of China was associated with nitrogen (N) and phosphorus (P) pollution, mainly due to the discharge of untreated rural wastewater (RW) into the surface water (SW) near villages of this region. A field experiment was conducted, using irrigation of RW plus urea fertilization under equal nitrogen (N) rate, namely, black water (BW), domestic wastewater (DW), gray water (GW), SW, and SW without any N application as a control (CK), to elucidate N removal by the paddy wetland system during the rice growing season of 2007.