Development of a simple and low-cost method using Moringa seeds for efficient virus concentration in wastewater.

Effective virus concentration methods are essential for detecting pathogenic viruses in environmental waters and play a crucial role in wastewater-based epidemiology. However, the current methods are often expensive, complicated, and time-consuming, which limits their practical application. In this study, a simple and low-cost method was developed using the extract of Moringa oleifera (MO) seeds (MO method) to recover both enveloped and non-enveloped viruses, including pepper mild mottle virus (PMMoV), murine norovirus (MNV), Aichivirus (AiV), murine hepatitis virus (MHV), and influenza A virus subtype H1N1[H1N1] in wastewater. The optimal conditions for the MO method were determined to be a concentration of MO extract at the UV280 value of 0.308 cm-1 and an elution buffer (0.05 M KH2PO4, 1 M NaCl, 0.1 % Tween80 [v/v]) for recovering the tested viruses in wastewater. Compared to other commonly used virus concentration methods such as InnovaPrep, HA, PEG, and Centricon, the MO method was found to be more efficient and cost-effective in recovering the tested viruses. Moreover, the MO method was successfully applied to detect various types of viruses (PMMoV, AiV, norovirus of genotype II [NoV II], enterovirus [EV], influenza A virus [matrix gene] [IAV], and SARS-CoV-2) in raw wastewater. Thus, the developed MO method could offer a simple, low-cost, and efficient tool to concentrate viruses in wastewater.

Adsorption behavior and mechanism of As(V) on magnetic Fe3O4-graphene oxide (GO) nanohybrid composite material.

In this study, the magnetic Fe3O4-graphene oxide (GO) nanohybrid composite material was prepared via the combination of the modified Hummer's method and coprecipitation. The morphology of the hybrid sample showed that the diffusion of Fe3O4 nanoparticles into the porous channels of mesoporous GO layers not only restricted the restacking of GO nanosheets but also prevented the leaching and agglomeration of magnetic nanoparticles. The result of the kinetic and isotherm studies that were performed to evaluate the adsorption mechanism showed a good fit with the pseudo-second-order kinetic and Langmuir isotherm models. The As(V) adsorption efficiency, H, of the GO/Fe3O4 nanohybrid composite material reached the maximum value of 99.37% after 60 min. The maximum adsorption capacity qm of the GO/Fe3O4 nanohybrid material was 14.1 mg·g-1 in an acidic aqueous solution (pH 1). The role and contribution of GO and Fe3O4 nanoparticles in adsorption and the improvement in As(V) adsorption efficiency were also investigated in further detail. The findings of this work suggested that the GO/Fe3O4 nanohybrid material could be widely applied for polluted water treatment.

Submerged nanofiltration without pre-treatment for direct advanced drinking water treatment.

Membrane fouling is a major challenge toward achieving direct nanofiltration (NF) treatment of surface water. This study aimed to evaluate the potential of the novel submerged flat-sheet NF membrane module to achieve low fouling propensity and high separation performance during the direct filtration of surface water. Laboratory-scale NF tests showed that the transmembrane pressure (TMP) increased only by 10 kPa over 24 d during the direct treatment of river and dam water. The NF system showed high (>80%) and stable rejection of color and organics, as well as low and variable conductivity rejection (28-47%). The rejection of negatively charged trace organic chemicals (TOrCs) was >50%, while that of uncharged or positively charged TOrCs was <50%. Another NF test that was conducted at a drinking water treatment plant showed negligible membrane fouling with a TMP increase of 3 kPa over 35 d. Separation performance of the NF system remained high: total organic carbon (TOC) removal was >70%, which was greater than the conventional rapid sand filtration system with powdered activated carbon and intermediate chlorine doses (TOC removal = 20-60%). Overall, this study demonstrated high water quality and stable system operation of the submerged flat-sheet NF system during direct treatment of surface water.

Protein hydrolysis and fermentation under methanogenic and acidifying conditions.

BACKGROUND: Many kinds of wastewaters contain appreciable quantities of protein. Anaerobic processes are suitable for the treatment of wastewater high in organics to achieve pollution control and recovery of energy as methane and hydrogen, or intermediates for production of biofuels and valuable biochemicals. A distinction between protein hydrolysis and amino acid fermentation, especially for dissolved proteins, is needed to target which one is truly rate-limiting and to effectively harvest bioproducts during anaerobic conversion of these wastewaters. This study explored mesophilic anaerobic hydrolysis and amino acid fermentation of gelatine, as a model for dissolved proteins, at pH 7 and at pH 5. RESULTS: The results showed that at pH 7, protein hydrolysis (first-order rate of 0.15 h-1) was approximately 5 times faster than acidification of the hydrolysis products (first-order rate of 0.03 h-1), implying that not hydrolysis but acidification was the rate-limiting step in anaerobic dissolved protein degradation. This was confirmed by (temporary) accumulation of amino acids. Nineteen different amino acids were detected during the first 8 incubation hours of gelatine at neutral pH and the total chemical oxygen demand (COD) of these 19 amino acids was up to approximately 40% of the COD of the gelatine that was added. Protein hydrolysis at pH 5 was 2-25 times slower than at pH 7. Shifting the initial pH from neutral to acidic conditions (pH 5) inhibited protein degradation and changed the volatile fatty acids (VFA) product profile. Furthermore, the presence or absence of methanogenic activity did not affect the rates of protein hydrolysis and acidification. CONCLUSIONS: The findings in this study can help to set a suitable solid retention time to accomplish anaerobic degradation of protein-rich wastewaters in continuous reactor systems. For example, if the target is harvesting VFAs, methanogens can be washed-out for a shorter retention time while amino acid fermentation, instead of hydrolysis as assumed previously, will govern the design and solutions to improve the system dealing with dissolved proteins.

Assessment of urbanization impact on groundwater resources in Hanoi, Vietnam.

In this study, the impact of urban development on groundwater resources of Hanoi City was assessed in terms of: (1) change of land use practice, and (2) increasing groundwater abstraction due to urban population growth. To this end, a coupled hydrological rainfall-runoff and groundwater flow simulation with WetSpa and MODFLOW codes was carried out with a set of spatial and temporal data of meteo-hydrology, land use, groundwater abstraction, population growth, and losses from the city water supply and sewerage system. The results of the simulation indicate that infiltration from rainfall contributes with 53.6% to the recharge of the groundwater system in Hanoi City, followed by seepage from rivers and lakes (31%). The remaining 15.4% was attributed to leakage from the municipal water supply and sewerage networks. This study also suggests that the main cause of groundwater level's decline in the city is the extensive groundwater abstraction, while an increase of the urban impervious areas due to urbanization only causes a slight decrease of groundwater recharge.

Pepper mild mottle virus as an indicator and a tracer of fecal pollution in water environments: comparative evaluation with wastewater-tracer pharmaceuticals in Hanoi, Vietnam.

We analyzed pepper mild mottle virus (PMMoV) in 36 samples taken from surface water, wastewater, groundwater, tap water and bottled water in Hanoi, Vietnam. We then compared the occurrence and fates of PMMoV with pharmaceuticals and personal care products (PPCPs), which are known wastewater tracers. PMMoV was detected in 94% of the surface water samples (ponds, water from irrigated farmlands and rivers) and in all the wastewater samples. The PMMoV concentration ranged from 5.5×10(6)-7.2×10(6)copies/L in wastewater treatment plant (WWTP) influents, 6.5×10(5)-8.5×10(5)copies/L in WWTP effluents and 1.0×10(4)-1.8×10(6)copies/L in surface water. Among the sixty PPCPs analyzed, caffeine and carbamazepine had high detection rates in surface water (100% and 88%, respectively). In surface water, the concentration ratio of PMMoV to caffeine remained unchanged than that in WWTP influents, suggesting that the persistence of PMMoV in surface water was comparable to that of caffeine. The persistence and the large concentration ratio of PMMoV in WWTP influents to the method detection limit would account for its ubiquitous detection in surface water. In comparison, human enteric viruses (HEV) were less frequently detected (18-59%) than PMMoV in surface water, probably because of their faster decay. Together with the reported high human feces-specificity, our results suggested that PMMoV is useful as a sensitive fecal indicator for evaluating the potential occurrence of pathogenic viruses in surface water. Moreover, PMMoV can be useful as a moderately conservative fecal tracer for specifically tracking fecal pollution of surface water. PMMoV was detected in 38% of the groundwater samples at low concentrations (up to 19copies/L). PMMoV was not detected in the tap water and bottled water samples. In groundwater, tap water and bottled water samples, the occurrence of PPCPs and HEV disagreed with that of PMMoV, suggesting that PMMoV is not suitable as an indicator or a tracer in those waters.