PROJECT CRESCENT: A PROPOSAL TO BUILD A SUSTAINABLE MOONBASE

Be it harsh snowy mountains or dry hostile deserts, wherever there is space to expand into humans have done so boldly. With Earth mostly discovered and inhabited it is hardly surprising that many countries, organizations and space agencies are already making preparations to build permanent settlements and bases throughout the solar system starting with the Moon and Mars. The Moon our only satellite and the closest celestial body to the Earth is the next logical step in the ladder to becoming an interplanetary civilization. We have the technology to do so and NASA’s current estimates say it could be possible with a budget of 20 to 40 billion Dollars spread over the time of a decade. This budget is comparable to that of the International Space Station or a mere 1% of the United States Federal Budget in 2019. A small investment with an immeasurable payoff if done right. This is a step in the right direction towards becoming a type 2 civilization on the Kardashev scale, develop new technologies and discover new sources of energy

Hydrothermal process reduced Pseudomonas aeruginosa PAO1-driven bioleaching of heavy metals in a novel aerated concrete synthesized using municipal solid waste incineration bottom ash

Development of innovative and sustainable technologies for recycling of municipal solid waste incineration bottom ash (IBA) are urgently needed for countries with limited land resources to prolong the lifespan of landfill sites. This study first attempted to reutilize IBA for synthesis of a novel aerated concrete by hydrothermal reaction. Moreover, impact of hydrothermal process on heavy metal bioleaching behavior of the synthesized material was investigated. Concrete specimens were prepared by optimum reuse of 20% IBA with replacement of cement in the mix matrix, then treated hydrothermally. A series of well-designed bioleaching experiments were carried out on samples of raw IBA, untreated and hydrothermally treated concretes in synthetic groundwater media using an environmental bacterium, Pseudomonas aeruginosa PAO1. The findings demonstrated that interactions between bacteria (strain PAO1) and IBA/concretes accelerated heavy metal leaching. Nonetheless, hydrothermal treatment has dramatic effects on immobilization of heavy metals because significant reduction (29–100%) of toxic metal (Cu, As, Pb and Cr) bioleaching observed. FE-SEM depicted a clear morphology change with plate, fibrous and needle-like structures, whereas XRD pattern indicated possible formation of a new calcium silicate hydrate (C-S-H) containing mineral (tobermorite) by hydrothermal reaction, and tobermorite might cause fixing of heavy metals by structural exchange of Ca2+ by metal ions. This study suggests production of construction materials using IBA by hydrothermal process could be an attractive option for recycling of IBA or similar properties of wastes.National Environmental Agency (NEA)The authors would like to acknowledge support from the Environment Technology Research Program (ETRP), National Environment Agency, Singapore (Project No. ETRP 1301 104). Moreover, we thank to Dr. Bin Cao at Nanyang Technological University for providing P. aeruginosa strain PAO1 and useful discussion for this study

Biological and physicochemical wastewater treatment processes reduce the prevalence of virulent Escherichia coli

Effluents discharged from wastewater treatment plants are possible sources of pathogenic bacteria, including Escherichia coli, in the freshwater environment, and determining the possible selection of pathogens is important. This study evaluated the impact of activated sludge and physicochemical wastewater treatment processes on the prevalence of potentially virulent E. coli. A total of 719 E. coli isolates collected from four municipal plants in Qu\ue9bec before and after treatment were characterized by using a customized DNA microarray to determine the impact of treatment processes on the frequency of specific pathotypes and virulence genes. The percentages of potentially pathogenic E. coli isolates in the plant influents varied between 26 and 51%, and in the effluents, the percentages were 14 to 31%, for a reduction observed at all plants ranging between 14 and 45%. Pathotypes associated with extraintestinal pathogenic E. coli (ExPEC) were the most abundant at three of the four plants and represented 24% of all isolates, while intestinal pathogenic E. coli pathotypes (IPEC) represented 10% of the isolates. At the plant where ExPEC isolates were not the most abundant, a large number of isolates were classified as both ExPEC and IPEC; overall, 6% of the isolates were classified in both groups, with the majority being from the same plant. The reduction of the proportion of pathogenic E. coli could not be explained by the preferential loss of one virulence gene or one type of virulence factor; however, the quinolone resistance gene (qnrS) appears to enhance the loss of virulence genes, suggesting a mechanism involving the loss of pathogenicity islands.Peer reviewed: YesNRC publication: Ye

Integrated self-forming dynamic membrane (SFDM) and membrane-aerated biofilm reactor (MABR) system enhanced single-stage autotrophic nitrogen removal

The membrane aerated biofilm reactor (MABR) is a novel bioreactor technology, facilitating single-stage auto-trophic nitrogen removal. Two laboratory-scale MABRs equipped with non-woven fabrics were operated simultaneously without and with a self-forming dynamic membrane (SFDM) filtration module. After 87 days of operation (system start-up), the reactor incorporated with SFDM filtration showed better performance in terms of total nitrogen removal (>80%) and effluent suspended solid (less than1 mg/L) than the MABR in the up flow anaerobic sludge blanket (UASB) configuration (i.e., without SFDM). The incorporation of SFDM has the ability to retain more slow growing biomass (anammox) inside the reactor. Microbial characterization by 16S rRNA-based amplicon sequencing shows that the abundance and composition of microbial communities in two MABR systems were different, i.e., the genus Rhodanobacter was abundant in UASB-MABR, while Calorithrix was dominant in SFDM-MABR. PCA-based statistical analysis demonstrated a positive association between reactor performance, membrane characteristics and microbial communities

Leaching of metals from incineration bottom ash using organic acid

The municipal solid waste incineration bottom ash (IBA) is increasingly used as a secondary resource for civil engineering and various other applications. IBA contains various metals. The presence of these metals may limit the use of IBA as a secondary resource. This can be overcome by removing metals from IBA. This study focused on determination of metal contents of IBA and leaching of these metals. The results show that calcium (Ca), iron (Fe), aluminum (Al), silicon (Si), and sodium (Na) are the major metals present in IBA. Many other metals ranging from magnesium (Mg) to mercury (Hg) were also present in varying quantities. In the present study, four organic acids, namely, citric, malic, oxalic, and gluconic acids have been used to compare the metal leaching from IBA. The citric acid was found to be the most effective leaching agent. Various process parameters for metal leaching were optimized. It was found that the maximum metal leaching was achieved in 48 h. The 1 M citric acid, 100 mL working volume, 150 rpm, and 30 °C were the optimal conditions to leach 100 wt% Si, Na, Au, Sb, respectively. Around 99 wt% Mg, 95 wt% K, 93 wt% Cd, 88 wt% Al, 84 wt% Ca, 80 wt% Fe, 79 wt% Sr, 77 wt% Pb, Zn, As respectively, 67 wt% Cu, V, Ag respectively, 66 wt% Mn, 64 wt% Co, 56 wt% Cr, 43 wt% Ni, Sn respectively, 40 wt% Se, 21 wt% Ba, 10 wt% Hg were leached using citric acid at optimal conditions. The leaching efficiency decreased with increasing pulp density. An optimal pulp density for metal leaching was observed at 1% (w/v). The method described in the present study provides an alternative environmentally friendly process to remove metals from IBA. This will facilitate the recycling of metal-free IBA for geotechnical applications.National Environmental Agency (NEA)The authors would like to acknowledge the financial support from the Environment Technology Research Program (ETRP), the National Environment Agency, Singapore (ETRP Nos. 1301 104)

Conceptual Design of Mars Sub-Surface Habitat for Sustaining Thermal Stability

The surface of Mars is seasoned with hostile climate, recurrent dusty sand storms, exposure to galactic cosmic radiation, and temperature variance that persuaded a challenging environment for performing science mission operations. A human mission to Mars requires extended presence for approximately 180-270 days since regular interplanetary transit is limited due to its far distance and technology limitation. So it is significant to have a confined habitat that can ensure crew protection as well as sustainable presence thereby affording necessities. In addition to this, the surface temperature of Mars varies from (-125°C to 20°C) that pose a greater challenge for life forms and crews to sustain thermal stability. Improper temperature balance may lead the crew to experience the effect of hypothermia and frost formation. Hence considering the entire challenges of human survival of Mars, we propose a novel “Mars Sub-Surface Habitat” capable of stabilizing habitat’s internal temperature during night-time. Further, the habitat is environment tolerant to keep the astronauts secure from every critical condition. Its thermal stability is enhanced by the thickened wall structure sealed with either in-situ thermal insulating material or synthetic insulators. Apart from its wall design, its potentiality to isolate itself from the surface environment at night triggers additional temperature stability. Keeping eye on the forthcoming human expedition mission and the strategy for human settlement, we hope this kind of habitat may afford a favourable compact home for a safe and sustainable mission. The habitat is proposed base on the concept that the subsurface of Mars seems to be a perfect platform for future Martians

Dynamic anaerobic membrane bioreactor coupled with sulfate reduction (SrDMBR) for saline wastewater treatment

This study investigated organic removal performance, characteristics of the membrane dynamics, membrane fouling and the effects of biological sulfate reduction during high-salinity (1.0%) and high-sulfate (150 mgSO(4)(2-)- S/L) wastewater treatment using a laboratory-scale upflow anaerobic sludge bed reactor integrated with cross -flow dynamic membrane modules. Throughout the operational period, dynamic membrane was formed rapidly (within 5-10 min) following each backwashing cycle (21-16 days), and the permeate turbidity of < 5-7 NTU was achieved with relatively high specific organic conversion (70-100 gTOC/kgVSS.d) and specific sulfate reduction (50-70 gSO(4)(2-)-S/kgVSS.d) rates. The sulfide from sulfate reduction can be reused for downstream autotrophic denitrification. 16S rRNA gene amplicon sequencing revealed that the microbial communities enriched in the sludge were different than those accumulated on the dynamic layer. Overall, this study demonstrates that the anaerobic dynamic membrane bioreactor coupled with sulfate reduction (SrDMBR) shows promising applica-bility in saline wastewater treatment

Impact of UV and peracetic acid disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic escherichia coli in wastewater effluents

Wastewater discharges may increase the populations of pathogens, including Escherichia coli, and of antimicrobial-resistant strains in receiving waters. This study investigated the impact of UV and peracetic acid (PAA) disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli (UPEC), the most abundant E. coli pathotype in municipal wastewaters. Laboratory disinfection experiments were conducted on wastewater treated by physicochemical, activated sludge, or biofiltration processes; 1,766 E. coli isolates were obtained for the evaluation. The target disinfection level was 200 CFU/100 ml, resulting in UV and PAA doses of 7 to 30 mJ/cm2 and 0.9 to 2.0 mg/liter, respectively. The proportions of UPECs were reduced in all samples after disinfection, with an average reduction by UV of 55% (range, 22% to 80%) and by PAA of 52% (range, 11% to 100%). Analysis of urovirulence genes revealed that the decline in the UPEC populations was not associated with any particular virulence factor. A positive association was found between the occurrence of urovirulence and antimicrobial resistance genes (ARGs). However, the changes in the prevalence of ARGs in potential UPECs were different following disinfection, i.e., UV appears to have had no effect, while PAA significantly reduced the ARG levels. Thus, this study showed that both UV and PAA disinfections reduced the proportion of UPECs and that PAA disinfection also reduced the proportion of antimicrobial resistance gene-carrying UPEC pathotypes in municipal wastewaters.Peer reviewed: YesNRC publication: Ye