Journal of Environmental Engineering

The use of greywater or treated wastewater for the irrigation of public greenspaces and athletic fields is becoming a management strategy in water conservation. Water may contain pharmaceuticals and personal care products (PPCPs), as well as oxide nanoparticles (NPs), because these compounds have been detected in sediment-freshwater systems and soils. This study investigated interactions between PPCPs and NPs by batch adsorption experiments using five soil-associated NPs (${\mathrm{Fe}}_2{\mathrm{O}}_3$, MgO, ${\mathrm{SiO}}_2$, ${\mathrm{Al}}_2{\mathrm{O}}_3$, and CaO), one common anthropogenic NP (${\mathrm{TiO}}_2$), fine ($<37\mathrm{\mu m}$) fractions of athletic field soils, and seven PPCPs: salicylic acid, propranolol, carbamazepine, bisphenol A, diclofenac, caffeine, and ibuprofen. Results indicated that some sorption can be determined by the net surface charge of the oxide NP or the composite mineralogy of the soil fines, and the overall charge of the attendant PPCPs, over the pH range of the experiments ($\sim 6–8$). However, adsorption of several drug–substrate pairs was not explained by net surface charge attraction or repulsion, and data indicated that more-complex adsorption mechanisms are operative in water–soil systems containing the relatively hydrophilic PPCPs investigated.

A great challenge for water managers and stakeholders is the maintenance and improvement of basin sustainability, tackling the ever-increasing threats and impacts. Some catchments, such as the Paranoá River basin (Central Brazil), are facing rapid urbanization, with increasing water demand and water quality impacts that threaten their sustainability. To assess this, two basin indices, the Watershed Sustainability Index (WSI) and the Water Resources System Dynamics (WRSD), were applied to the Paranoá basin in the period between 2015 and 2018. Off-the-shelf data and tailored surveys were used as information sources. The basin WRSD and WSI scores were 0.33 and 0.60, respectively, corresponding to a medium level of hydrologic and integrated sustainability. The WSI bottlenecks were the high unit water demand in the basin, and the incipient management responses with respect to the basin’s environment, livelihood, and policy indicators. For the WRSD index, high water demand was the limiting sustainability factor. Adaptation measures to improve basin sustainability include effective water demand management and the establishment of new protected areas in the catchment.

Per- and polyfluoroalkyl substances (PFASs) are recalcitrant emerging contaminants of concern within the United States and internationally. Of the known PFASs, the sulfonates are considered among the most toxic and difficult to destroy using traditional methods. Research presented herein describes the degradation and defluorination of perfluorooctane sulfonate (PFOS) using a novel photocatalytic porous silica-based granular media (SGM) activated with ultraviolet light, and combined with a strong or weak nucleophilic attack in batch reactors. Sodium thiosulfate proved to be the most compatible and efficient nucleophile in combination with SGM media production of free radicals. Measured aqueous fluoride content accounted for 51% defluorination of PFOS, while the remainder is theorized to mineralize and reside within the porous network of the SGM, as indicated by scanning electron microscopy and energy dispersive x-ray spectroscopy. Removal of PFOS in solution is completed by 30 min with ${\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3$, with measurable by-product production of ${\mathrm{C}}_2{\mathrm{F}}_3{\mathrm{O}}_2^{-}$ and aqueous fluoride occurring at 15 min. The rapid increase, incipient decrease, and subsequent mineralization of fluoride reveals that the degradation of PFOS is rapid and starts with cleaving of the functional sulfonate group. Amalgamated C-F chains precipitate within the SGM alongside the crystalized fluorine. Possible pathways for PFOS destruction are proposed for the combined attack results. This approach is translatable to other PFASs and organic contaminants of concern.

Comparative analysis of hybridized microbial fuel cell (MFC) with constructed wetland systems (CW) as continuous and batch flow in with/without plant setups has been done. The sewage-generated WW was spiked with reverse osmosis (RO) concentrate [1:1] and was used as the substrate. The effects of RO-induced salinity and efficiency of wastewater (WW) biomass conversion to energy have been analyzed. The analysis was based on the removal of chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS), voltage generation, and energy recovery (NERs) to find out the performance efficiency of the four systems. Systems consisted of two batch setups with the downflow regime, batch setup with plant (BWP) and batch setup without plant (BWOP) and two continuous setups with the upflow regime, continuous setup with plant (CWP) and continuous setup without plant (CWOP). The maximum COD removal and energy recoveries in BWP, BWOP, CWP, and CWOP were 91.66%, 86.45%, 90.62%, and 83.33% and 6.20, 1.98, 0.98, and 0.72 W·h/kgCOD, respectively. The incorporation of RO concentrate positively influenced the performance of CW-MFCs by its induced salinity specifically in presence of Canna indica, thus increasing the energy output as indicated by the voltage generation and energy recoveries.

Various reactive treatment materials were evaluated to enhance sand filtration of dissolved species common in stormwater runoff: ${\mathrm{NO}}_3^{-}$, ${\mathrm{PO}}_4^{3-}$, ${\mathrm{Cu}}^{2+}$, ${\mathrm{Pb}}^{2+}$, and ${\mathrm{Zn}}^{2+}$. Fly ash and iron oxyhydroxide mine drainage residuals were blended with sand at 5% (FA5.0) and 7.5% (MDR7.5) by mass and packed into laboratory columns. Additionally, minus 30 mesh particle sizes of proprietary peat products APTsorb and bioAPT were each packed without blending with a succeeding sand layer (APT-S and BIO-S). Pollutant removal performance was evaluated by pumping synthetic stormwater (SS) through packed up-flow columns without recirculation. The control material was 100% sand (SAND). Target SS concentrations included $1.5\mathrm{mg}/\mathrm{L}{\mathrm{NO}}_3^{-}$ as N, $0.5\mathrm{mg}/\mathrm{L}{\mathrm{PO}}_4^{3-}$ as P, $25\mathrm{\mu g}/\mathrm{L}{\mathrm{Cu}}^{2+}$, $30\mathrm{\mu g}/\mathrm{L}{\mathrm{Pb}}^{2+}$, and $100\mathrm{\mu g}/\mathrm{L}{\mathrm{Zn}}^{2+}$. FA5.0 and MDR7.5 both removed over 84% of P. SAND, APT-S, and BIO-S removed limited total P and total dissolved P, while BIO showed a net export of up to 30% P. All columns removed greater than 75% and 89% of ${\mathrm{Cu}}^{2+}$ and ${\mathrm{Zn}}^{2+}$, respectively. APT-S removed the greatest ${\mathrm{Pb}}^{2+}$, at over 84%. None of the columns exhibited consistent ${\mathrm{NO}}_3^{-}$ removal greater than 10%.

In the quest to find a nanoadsorbent for the removal of 4-nonylphenol (4-NP) from contaminated water, graphene oxide chitosan aerogel (GOCSA) beads were synthesized and characterized as a potential candidate in our earlier study in the batch system. In this study, the adsorption status of the nanocomposite was investigated using continuous fixed-bed column tests to determine the potential and performance of the adsorption. To evaluate the performance of the adsorbent, bed depth (10–20 cm), flow rate ($10–20\mathrm{L}{\min }^{-1}$), and concentration ($1–3\mathrm{mg}{\mathrm{L}}^{-1}$) of 4-NP were measured and the breakthrough curves for each condition were drawn. The column adsorption structure was found to operate better with higher bed depth, lower flow rate, and lower 4-NP influent concentration with 8.94 L breakthrough volume. The highest adsorption capacity of $18.53\mathrm{mg}{\mathrm{g}}^{-1}$ was achieved using 20 cm bed depth, $10\mathrm{mL}{\min }^{-1}$ flow rate, and $3\mathrm{mg}{\mathrm{L}}^{-1}$ influent 4-NP concentration. Finally, the parameters related to the Thomas, Adams–Bohart, and Yoon–Nelson models were calculated. It was found that the outcomes are consistent with the Thomas and Yoon–Nelson models.

The remediation of sites contaminated with chlorinated hydrocarbons (CHCs) poses a challenge, especially in built up areas. Nanoscale zero-valent iron (nZVI) can reduce CHCs to nontoxic compounds. Jet grouting and deep soil mixing is used to overcome the difficulty of homogeneous distribution of nZVI in heterogeneous soils. Because these techniques facilitate a synergistic contaminant treatment and installation of construction elements, it is important to know the reactive interactions among involved compounds. In this study six binder materials [bentonite and ordinary portland cement (OPC), among others] have been investigated for interactions with the reductive dechlorination of trichloroethylene (TCE) by nZVI. The installation process was simulated in batch experiments, and the reaction products (CHC, intermediate products, and hydrogen) were observed using headspace gas chromatography. None of the binders inhibited dechlorination of TCE compared to a control experiment, and the two clay materials even catalyzed the reaction by a factor of up to 12.9. Hydrogen evolution was determined as a sensible indicator for the suitability of a particular binder, ranging from 12.8 to 4,400 mmol.

Polycyclic aromatic hydrocarbons (PAHs) are potentially carcinogenic organic compounds that are persistent in the environment. The peroxy-acid treatment is an advanced oxidation process (AOP) that can effectively degrade recalcitrant organic compounds. In this study, the degradation of four PAH compounds (anthracene, benzo[a]pyrene, phenanthrene, and pyrene) with peroxy-acid treatment was investigated. For each compound, a pseudo-first order rate constant for the peroxy-acid treatment process was determined at three different temperatures (25°C, 32°C, and 40°C) over a 24-h period. Reactions took place in $35\mathrm{mL}$ centrifuge tubes with volume ratios of $3:3:9$ ($\mathrm{v}/\mathrm{v}/\mathrm{v}$) acetic acid/50% hydrogen peroxide/DI water, resulting in a total volume of $15\mathrm{mL}$ in each reaction vessel. As treatment progressed, the hydrogen peroxide and peracetic acid (PAA) in the solution decreased and increased, respectively. In decreasing order, the overall degradation efficiency using a peroxy-acid treatment was anthracene, benzo[a]pyrene, pyrene, and phenanthrene. The activation energy for the reaction scheme was 139.0 for anthracene, 83.1 for phenanthrene, 126.8 for pyrene, and $133.1\mathrm{kJ}{\mathrm{mol}}^{-1}$ for benzo[a]pyrene. In addition, the relationship between the property-encoded surface translator (PEST) molecular descriptors and thermodynamic parameters was investigated. Highly-correlated, linear relationships were found, which can be used to estimate the reactivity of other PAHs using peroxy-acid as a treatment choice. Overall, the peroxy-acid treatment process proved to be effective in treating PAH compounds and achieved results comparable to other AOPs used for PAHs. The developed model based on experimental and computational molecular data can serve as a powerful predictive tool, which will decrease the time and need for expensive experimental work when using peroxy-acid as an AOP for PAHs. Further studies with other matrices (such as sediment and soil) and PAH compounds will strengthen the model and provide wider field application.

Various studies have provided insights about how green roof rainfall retention capacity is affected by factors including typology, vegetation, growing media’s physical-chemical-biological properties, drainage system, climate conditions, and roof age. Despite its importance, little has been studied about the effect of drainage area on green roof retention capacity. In this work, three experimental extensive green roof units with different drainage areas ($1{\mathrm{m}}^2$, $3{\mathrm{m}}^2$, and $12{\mathrm{m}}^2$) were assessed to evaluate how the rainfall characteristics and the scale dynamics of the green roofs impact the retention during rainfall events. The findings showed that the drainage area had a significant impact on rainfall retention and outflow volumes. The average retention capacity increased, and the outflow generation capacity decreased with increasing drainage area. The largest green roof area ($12{\mathrm{m}}^2$) presented better performance with respect to rainfall retention, being 36% higher than the $1{\mathrm{m}}^2$ area, and 13% higher than the $3{\mathrm{m}}^2$ green roof area. In turn, the performance of the $3{\mathrm{m}}^2$ green roof was 21% higher than the $1{\mathrm{m}}^2$ area. Factors such as rainfall depth and maximum $1\text{-}\mathrm{h}$ rainfall intensity also affected the retention and outflow behavior. However, the antecedent dry weather period had little effect on retention and outflow, possibly due to frequent rainfall caused by subtropical climate.

The treatment and disposal of organic household and industrial waste is a global issue. Several environmental, social, and economic problems are associated with current waste management practices. Composting biowaste is a financially affordable and easy-to-use method, while compost, the final product, can improve various soil properties. In this study, composting was selected for the treatment and valorization of food waste and olive mill waste. About 750 kg of leftovers from the university restaurant were used as primary material together with a small amount (2%–4%) of olive mill waste to form three compost heaps: food waste (F), food/olive mill waste/leaves (FOL), and food waste/olive mill waste (FOS). Physicochemical properties such as temperature, oxygen content, pH, and C/N ratio were measured to evaluate the raw materials, the composting process, and the final product. In addition, the degree of stability and phytotoxicity of the composts were evaluated by static respiration tests (SRT) and germination tests. At the onset of the experiment, waste from the olive mill inhibited composting for several days, but then developed into a standard composting process. The final products of piles F, FOL, and FOS were evaluated as stable, with cumulative respiration index (CRI) values of 6.2, 9.9, and $6.7\mathrm{O}2/\mathrm{kg}$ (dry weight), respectively, but also as phytotoxic due to the low germination index (GI), with values of 58%, 72%, and 68% corresponding to 80% chosen as the limit value. Nevertheless, the results of the germination tests indicate that the addition of olive mill waste in the composting of food waste can potentially improve seed germination, as shown by the higher GI values of FOL and FOS samples compared with the F sample, and consequently can improve the quality of the compost.