Water, Air, and Soil Pollution

Many of municipal wastewater treatment plants (WWTPs) are operated by biological process with their excellent performances. However, the early warning system in the influent line is required to avoid the process malfunction because the biological wastewater treatment system has serious drawback to toxic chemicals in the influent. In order to develop a new type of biosensor using anaerobic granules in an online device for rapid detection of toxic inhibitory to the biological process, a porous pot reactor and an anaerobic granule biosensor (AGB) were demonstrated as an upset early warning device (UEWD) in this study. In the first group of toxic loading tests, the prepared cupric chloride solutions were separately injected into both the porous pot and AGB systems at six different concentrations, and phenol solutions were used at three different concentrations in the second group of tests. The results showed the chemical oxygen demand (COD) and ammonia nitrogen (ammonia-N) removal efficiency from porous pot reactor decreased dramatically in response to the addition of Cu2+ and phenol with the variation of the oxidation-reduction potential (ORP) in AGB. The response of AGB system was 6 to 20 h in advance of porous pot reactor performance response, which suggests that the AGB could potentially be used as an online UEWD.

Emerging contaminants (ECs) have been studied extensively because of the various damages they can cause to the environment, especially due to the non-treated domestic effluents, which contaminate the water bodies. Therefore, it is important to evaluate alternatives to remove these compounds. The objective of this work was to evaluate the potential of a new biosorbent from chitosan modified with vanillin (CTSV) to remove isoniazid, cortisol, bisphenol A, 17α-ethinylestradiol, and triclosan by competitive adsorption studies. Structural characterization of the biosorbents was performed by Fourier transform infrared spectroscopy, thermogravimetry, Brunauer-Emmett-Teller, zeta potential, scanning electron microscopy, and 1H nuclear magnetic resonance. The adsorption for ECs were carried out in an aqueous medium, and quantitative analyzes were performed by HPLC. The effect of pH was evaluated in the pH range 5 to 10 and indicated that better results were found in pH 9 and 8 for CTS and CTSV, respectively. The salt concentrations effect was evaluated in 0.0 to 1.0 mol L−1 and revealed better adsorption conditions in 0.7 mol L−1 of NaCl. The adsorption kinetics pointed to an equilibrium condition reached quickly (with adjustment of data R2 > 0.969) with adequacy to pseudo–second-order model for both biosorbents and ECs. The linear isothermal model was suitable for the adsorption isothermal data and distribution constant (KD) showed the highest values for 17α-ethinylestradiol (0.067 L g−1) and triclosan (0.197 L g−1) in CTSV adsorption. Thus, the results indicated that CTSV performed well in removal for the tested ECs, being an interesting alternative, due to the ease of obtaining and abundance of reagents employed in its preparation.

A pure clay ball and surface-modified clay ball were investigated to remove phosphate from synthetic wastewater; phosphate causes eutrophication in hydro-ecological systems. Adsorption tests of phosphate from aqueous solutions onto two types of adsorbents were conducted. The maximum phosphate adsorption capacities of the pure and surface-modified clay ball were found to be 0.084 and 8.869 mg/g, respectively. In a fixed-bed column packed with surface-modified clay balls, the first breakthrough of phosphate appeared after approximately 4000 min. In addition, the phosphate adsorbed on the surface-modified clay ball was effectively desorbed using a 1 M zirconium sulfate solution, and the adsorbent was regenerated for four adsorption and three desorption cycles by maintaining the adsorption capacity at the value before regeneration. X-ray diffraction (XRD), scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX), and Brunauer-Emmett-Teller (BET) analysis method were performed to reveal the characteristics of the surface-modified clay ball. Cytotoxicity experiment was conducted on the developed adsorbents, and as a result, these showed low cytotoxic effect on the human cells. These results indicated that the surface-modified clay ball, due to the low cost, high adsorption capacity, and non-toxicity, has the potential to be utilized in the cost-effective removal of phosphate from aqueous solutions.

Disposal of sewage sludge creates the potential for heavy metal accumulation in the environment. This study assessed nine soils currently used as Dedicated Land Disposal units (DLDs) for treatment and disposal of municipal sewage sludge in the vicinity of Sacramento, California. Adsorption characteristics of these soils for Cd, Cu, Ni, Zn, Pb, and Cr were studied by simultaneously mixing these elements in the range of 0–50μmol L−1 with sludge supernatant and reacting with the soil using a soil:supernatant ratio of 1:30, pH=4.5 or 6.5, and constant ionic strength (0.01M Na-acetate). The concentration of metals in the supernatant was determined after a 24 hr equilibration period. Adsorption isotherms showed that metal sorption was linearly related to its concentration in the supernatant solution. The distribution coefficient K d (K d = concentration on solid phase/concentration in solution phase) was computed as the slope of the sorption isotherm. The distribution coefficients were significantly correlated to soil organic matter content for Ni, Cu, Cd, and Pb at pH 4.5 and for Ni, Cu, Zn, and Cd at pH 6.5. There was also a correlation between K d and soil specific surface area but no relationship to other soil properties such as CEC, clay content, and noncrystalline Fe and Al materials. Therefore, soil organic carbon and surface area appear to be the most important soil properties influencing metal adsorption through formation of organo-metal complexes. The K d values for all elements were higher at pH 6.5 than at 4.5. Selectivity between metals resulted in the following metal affinities based on their K d values: Pb>Cu>Zn>Ni>Cd≈Cr at pH 4.5 and Pb>Cu≈Zn>Cd>Ni>Cr at pH 6.5.

Reversible decrease in CO2 fixation has been reported in rice plants exposed to low concentrations of SO2 (Matsuoka et al., 1969). Alpha hydroxy sulfonate is thought to form in leaves by an addition-reaction between plant aldehyde and SO2, and to inhibit the process of the photosynthesis. However, the identification of this compound in the leaves has not been successful. This report deals with the results of the radiochemical experiments to examine the occurrence of glyoxylate bisulfite, a-hydroxy sulfonate forms of glyoxylic acid in rice plant leaves exposed to radioactive sulfur dioxide. In plants exposed to SO2, sufficient amounts of glyoxylate bisulfite could be formed and thereby inhibit the progress of the path from glicolic to glyoxylic acid.

Salination and saltwater intrusion are common and increasing problems in coastal areas. This study investigates the susceptibility of soils and water resources to saline intrusion in the coastal areas of Cambodia in the context of climate change. Water samples were collected from tube wells (n = 8), dug wells (n = 25), canals (n = 7), ponds (n = 5), and rain water (n = 5) across the Koh Kong coastal area of Cambodia and measured for the contaminants of health concerns (As, Ba, NO3−, NO2−, F−, and Mn) and esthetic quality (Cu, Fe, and Zn) following USEPA methods. Water salinity and other physicochemical properties (Temperature, pH, ORP, conductivity, TDS, turbidity, and DO) were measured onsite using field instruments. Concurrently, surface agricultural soils were sampled at each site. Soil salinity was determined by soil/water extract method following a standard protocol. Analytical results revealed that approximately 12.5% of tube wells, 4% of dug wells, and 20% ponds were saline. Concurrently, 37.5% of tube wells and 58.4% of dug wells contained As greater than 10 μg L−1, exceeded WHO’s Drinking Water Quality Guideline. Geogenic barium, iron, and manganese groundwater contamination also was widespread regionally. Anthropogenic contaminants like nitrate and nitrate (from agricultural runoff) were lower, well Cambodian Drinking Water Quality Standards. Most of soil pH was in acidic condition. Most of agricultural soils in Koh Kong coastal area are not saline, but the agricultural fields close to coastline and/or in the estuarine are frequently saline. This study suggested that appropriate water treatment technologies are needed to provide safe drinking water to people residing in Koh Kong coastal areas, and that it is important to manage salinity to prevent future contamination. Moreover, adaptation actions should be further promoted in order to cope with the potential impacts of the climate change in this Koh Kong coastal area.

The drinking water treatment plant (WTP) of the city of Turin (NW Italy), with a treatment capacity of 40 × 106 m3/year, has a basin that is employed as a lagooning pretreatment facility. This study aims to assess the effect of the basin on several environmental parameters (temperature, dissolved oxygen (DO), turbidity, pH, chloride, nitrite, and total chlorophyll) of the river water before entering the WTP and monitor the changes inside the basin caused by the seasonal hydrological and biological cycles. Sampling was carried out on 16 dates over 3 years at the inlet and outlet channel of the basin and in five locations along three depth values (1, 6, and 12 m, i.e., at the bottom). The results of the 3-year monitoring campaign demonstrated that the basin had an effect on pH (p = 6.6 × 10−9), DO (p = 0.000072), turbidity (p = 0.011), and chlorophyll (p = 0.033). No significant changes regarding nitrite (p = 0.11), chloride (p = 0.94), and temperature (p = 0.66) were detected. The results gathered from the sampling campaign inside the basin demonstrated that, during the year, the basin experienced the following: two states of complete mixing in early spring and fall, when the differences in temperature between the surface and the bottom of the basin were less than 1 °C; a condition of late spring/summer stratification with a temperature difference between the surface and the bottom of 4–5 °C and a difference in DO, pH, and total chlorophyll concentration that increased throughout the spring season; and one or more states of summer circulation due to the weak stability of the warm season stratification. During the states of circulation, the persistent algae photosynthetic activity tended to cause a quick change in the concentration of DO, total chlorophyll, and pH value in the most superficial layer of the basin. The results of the principal component analysis (PCA) showed a strong direct relationship between the weight of the first component and the hydrodynamic states of the basin (stratification/circulation) and an inverse relationship between the weight of the second component and the intensity of photosynthetic activity of algae species.

This study examined the importance of the antioxidative defense mechanism during the application of simulated acid rain (SAR) pH 4, pH 3, pH 2, and pH 6 as control treatment in Cinnamomum philippinense seedlings. Analysis was carried out on 1, 10, and 15 days of spraying SAR. In our results, catalase (CAT), ascorbate peroxidase (APx), guaiacol peroxidase (GPOD), and glutathione reductase (GR) activity significantly were induced on 1 day of spraying SAR pH 3 and pH 2, suggesting that C. philippinense seedlings exposed to pH 3 and pH 2 acid rain for only 1 day were under oxidative stress, and antioxidant enzyme were apparently increased until 10 days of spraying SAR pH 4. However, on 10 days of spraying SAR pH 2, the accumulated intensity of acidity significantly inhibited the activities of CAT and APx accompanying with increased concentrations of malonydialdehyde (MDA). On the contrary, GPOD activity and the ascorbic acid ratio were remarkably increased when spraying SAR pH 2 for 15 days. Therefore, GPOD and ascorbate contribute to the scavenging of ROS at stronger acidity stresses. However, they were not enough to avoid cellular damage, since membrane lipids were injured, and necrosis appeared.

The effects of several factors on the settling rate of aluminiumhydroxide were investigated during chemical coagulation using aluminium salts. Experimental variables were pH, aluminium (III) concentration and the order of addition of reagents. Experiments were carried out at pH 5–8 and rapid settling was achieved when aluminium (III) solutions were added to Na2CO3 solutions near neutral pH, close to the minimumsolubility pH of Al(OH)3. For a narrow range of total Al concentration where Al(III) species were supersaturated with respect to the solid phase, Al(III)-added-to-carbonate type mixtures yielded a higher settling rate than mixtures obtainedby the reverse order of reagent addition. The results were interpreted by comparing the rates of formation of polymer andsolid (amorphous Al(OH)3) phases. It was concluded that Al(III) coagulants should be added to water containing natural or artificially incorporated carbonate alkalinity for rapid settling of Al(OH)3 flocs.

This study investigates the potential of anaerobic digestion (AD) as an alternative method to improve the treatment performance of wastewater treatment plants (WWTPs) in the presence of inhibitors. This work will focus on studying the effect of the presence of certain heavy metals on the structure of microbial community and biogas production pathways during anaerobic digestion between different substrates. Waste activated sludge (WAS) from both urban and industrial WWTPs was mixed with municipal solid waste (MSW) to investigate the effect on heavy metal concentrations, microbial population balance, biogas production, and energetic benefits following the stabilization of the process. The results showed that better performance was achieved with anaerobic co-digestion (AcoD) experiments. The highest biogas rates of 0.81 L/d and 0.7 L/d were obtained with AcoD of industrial sludge (IS) and urban sludge (US) with MSW, respectively. Microbial analysis using fluorescence in situ hybridization (FISH) was conducted to quantify the major Bacteria and Archaea groups. The Archaea content reached 72% and 68% for AcoD mixtures of IS/MSW and US/MSW, respectively. Therefore, the best performance was obtained with the IS/MSW mixture, which produced a net energy production of 33.4 kJ/d. Heavy metals appeared to have a stimulating effect on AcoD between WAS and MSW by enhancing microbial activity due to a larger contact area and, thus, a higher adsorption rate.