Global WWTP Microbiome-based Integrative Information Platform: From experience to intelligence

Domestic and industrial wastewater treatment plants (WWTPs) are facing formidable challenges in effectively eliminating emerging pollutants and conventional nutrients. In microbiome engineering, two approaches have been developed: a top-down method focusing on domesticating seed microbiomes into engineered ones, and a bottom-up strategy that synthesizes engineered microbiomes from microbial isolates. However, these approaches face substantial hurdles that limit their real-world applicability in wastewater treatment engineering. Addressing this gap, we propose the creation of a Global WWTP Microbiome-based Integrative Information Platform, inspired by the untapped microbiome and engineering data from WWTPs and advancements in artificial intelligence (AI). This open platform integrates microbiome and engineering information globally and utilizes AI-driven tools for identifying seed microbiomes for new plants, providing technical upgrades for existing facilities, and deploying microbiomes for accidental pollution remediation. Beyond its practical applications, this platform has significant scientific and social value, supporting multidisciplinary research, documenting microbial evolution, advancing Wastewater-Based Epidemiology, and enhancing global resource sharing. Overall, the platform is expected to enhance WWTPs' performance in pollution control, safeguarding a harmonious and healthy future for human society and the natural environment.

Climate change induced water stress and future semiconductor supply chain risk

Climate change is a driver of water stress risk globally. Semiconductor manufacturing requires large volumes of water. Existing research at the intersection of water stress risk and semiconductor manufacturing offers snapshots of current conditions but has not investigated how future climate scenarios may impact semiconductor supply chain security. This study combines location data for semiconductor manufacturing facilities with data on specific customer-supplier networks and with data for global water stress risk under three climate scenarios for the years 2030 and 2040. Results suggest that 40 percent of existing facilities, 24-40 percent of facilities under construction, and 40-49 percent of facilities announced since early 2021 are in basins of high- or extremely high water stress risks in 2030 and 2040. Network dynamics mean that water stress risks could cascade from individual firms or regions of concern to systemically throughout the network, thus negatively impacting semiconductor supply chain security globally.

Micro/nanoengineered agricultural by-products for biomedical and environmental applications

Agriculturally derived by-products generated during the growth cycles of living organisms as secondary products have attracted increasing interest due to their wide range of biomedical and environmental applications. These by-products are considered promising candidates because of their unique characteristics including chemical stability, profound biocompatibility and offering a green approach by producing the least impact on the environment. Recently, micro/nanoengineering based techniques play a significant role in upgrading their utility, by controlling their structural integrity and promoting their functions at a micro and nano scale. Specifically, they can be used for biomedical applications such as tissue regeneration, drug delivery, disease diagnosis, as well as environmental applications such as filtration, bioenergy production, and the detection of environmental pollutants. This review highlights the diverse role of micro/nano-engineering techniques when applied on agricultural by-products with intriguing properties and upscaling their wide range of applications across the biomedical and environmental fields. Finally, we outline the future prospects and remarkable potential that these agricultural by-products hold in establishing a new era in the realms of biomedical science and environmental research.

China's public health initiatives for climate change adaptation

China's health gains over the past decades face potential reversals if climate change adaptation is not prioritized. China's temperature rise surpasses the global average due to urban heat islands and ecological changes, and demands urgent actions to safeguard public health. Effective adaptation need to consider China's urbanization trends, underlying non-communicable diseases, an aging population, and future pandemic threats. Climate change adaptation initiatives and strategies include urban green space, healthy indoor environments, spatial planning for cities, advance location-specific early warning systems for extreme weather events, and a holistic approach for linking carbon neutrality to health co-benefits. Innovation and technology uptake is a crucial opportunity. China's successful climate adaptation can foster international collaboration regionally and beyond.

Fabrication of cationic cellulose nanofibrils/sodium alginate beads for Congo red removal

Congo red is hard to remove from dye wastewater due to its structure stability and high chemical oxygen demand. In this study, cationic cellulose nanofibrils (CCNF) prepared from herb residues was physically crosslinked with sodium alginate (SA) in the presence of calcium ions, and the obtained CCNF/SA beads were used to adsorb Congo red. Results showed that CCNF/SA beads with porous internal structure were beneficial to adsorption. The maximum adsorption capacity of Congo red could reach to 518.4 mg/g, which was superior to most cellulose-based adsorption materials. Furthermore, the equilibrium adsorption isotherms and XPS analysis indicated the adsorption for Congo red was a physical process, and hydrogen bond and electrostatic adsorption were proposed as dominant adsorption mechanism. In addition, the Congo red removal efficiency of the beads was still higher than 70% after three cycles. Therefore, this high efficiency and green beads have great potential as adsorbents for anionic dyes removal.

Activated sludge process enabling highly efficient removal of heavy metal in wastewater

Activated sludge process was a low-cost alternative method compared to the conventional physicochemical process for the treatment of heavy metal-containing wastewater. In the present study, the removal efficiency of Pb²⁺, Cu²⁺, and Ni²⁺ from wastewater by a sequencing batch reactor (SBR) activated sludge system was investigated, and the mechanism was revealed by static adsorption experiment of activated sludge. The results showed that the activated sludge in the SBR system was effective in removing Pb²⁺ and Cu²⁺ from wastewater at 10 mg·L^-1 initial concentration, with a removal efficiency of 83.1 ~ 90.0% for Pb²⁺ and 74.3 ~ 80.6% for Cu²⁺, respectively. However, the removal efficiency for Ni²⁺ was only 0 ~ 6.2%. Static adsorption experiments showed that the adsorption capacity of activated sludge for three heavy metals was shown as Pb²⁺  > Cu²⁺  > Ni²⁺. When the initial concentration was 20 mg·L^-1, the equilibrium adsorption capacity of activated sludge for Pb²⁺, Cu²⁺, and Ni²⁺ was 18.35 mg·g^-1, 17.06 mg·g^-1, and 8.37 mg·g^-1, respectively. The main adsorption mechanisms for Pb²⁺ and Cu²⁺ were ligand exchange, electrostatic adsorption, and surface organic complexation processes, but Ni²⁺ removal mechanism mainly included electrostatic adsorption and surface organic complexation processes, showing that Ni²⁺ removal was inhibited in the presence of Pb²⁺ and Cu²⁺. The physicochemical properties and microbial diversity of activated sludge were greatly affected by the heavy metals in the SBR system, and genus Rhodobacter was found to be dominant bacteria enabling resistance to heavy metal ions.

Utilization of resources in abandoned coal mines for carbon neutrality

Under the new vista of carbon neutrality, all industries in China face new challenges. As the pillar industry for fossil energy, the coal industry cannot blindly "de-coal". It is necessary to combine the two-way force associated with abandoned mines to turn energy into resources and problems into solutions. Innovation that combines emission reduction and neutralization can overcome the bottlenecks in carbon neutralization in abandoned mines, and help achieve the national carbon peak in 2030 and carbon neutrality in 2060. This involves the entire life cycle of the mine, including the status quo of abandoned coal mines, and the development of downstream industries. The development mode of resource utilization in abandoned mines in accordance with the national situation was summarized, and the suggestion of carbon neutralization in abandoned mines was put forward, which involves three steps: (1) Define the value of abandoned mines, consolidate energy market share, enjoy the policy dividend, and realize carbon neutralization breakthrough; (2) list the development path of carbon neutralization in abandoned mines, utilize photosynthesis to sequester carbon, combine industrial advantages to promote the development of a new energy industry, promote the integration of carbon emission, gathering, sequestration and utilization, realize carbon sequestration and mineralization in terminals and participate in carbon sink market allocation; (3) promote multiple simultaneous measures to solve existing problems, develop abandoned mines, and implement carbon neutralization goals.

Ag/polydopamine-coated textile for enhanced liquid/liquid mixtures separation and dye removal

Engineering a versatile platform that enables to separate both oil/water and oil/oil mixtures and remove dye from water is not easy. To address this challenge, we have developed an Ag/polydopamine-coated textile (Ag/PDA@textile) by chemically depositing Ag particles on the textile surface using polydopamine as the binder layer. The obtained Ag/PDA@textile attracts water but repels oil in the air, underwater, and when immersed into the oil. Exploiting its water-attracting and oil resistance, the Ag/PDA@textile is acted as a separation membrane to separate oil/water mixtures with enhanced separation efficiency. The Ag/PDA@textile also possesses opposite wetting behavior to oils with different polarities, allowing it to separate oil/oil mixtures efficiently. Thanks to the catalytic performance of the Ag particle, organic dyes can be decomposed effectively by our Ag/PDA@textile under UV illustration or in the presence of NaBH₄. Our Ag/PDA@textile may be valuable for applications in water purification and oil sewage treatment.

A review on the applications of microbially induced calcium carbonate precipitation in solid waste treatment and soil remediation

Improper disposal and accumulation of solid waste can cause a number of environmental problems, such as the heavy metal contamination of soil. Microbially induced calcium carbonate precipitation (MICP) is considered as a promising technology to solve many environmental problems. Calcium-based solid waste can be utilized as an alternative source of calcium for the MICP process, and carbonate-based biominerals can be used for soil remediation, solid waste treatment, remediation of construction concrete, and generation of bioconcrete. This paper describes the metabolic pathways and mechanisms of microbially induced calcium carbonate precipitation and highlights the value of MICP for solid waste treatment and soil remediation applications. The factors affecting the effectiveness of MICP are discussed and analyzed through an overview of recent studies on the application of MICP in environmental engineering. The paper also summarizes the current challenges for the large-scale application of this innovative technology. In prospective study, MICP can be an effective alternative to conventional technologies in solid waste treatment, soil remediation and CO₂ sequestration, as it can reduce negative environmental impacts and provide long-term economic benefits.

Investigation of Taguchi optimization, equilibrium isotherms, and kinetic modeling for cadmium adsorption onto deposited silt

The feasibility of deposited silt as an adsorbent to eliminate Cadmium (Cd) from aqueous solution is assessed in this study. The optimum adsorption condition was determined with the help of the Taguchi experimental design. The treatment process of the deposited silt is controlled by various parameters like pH of the solution; a dose of deposited silt; initial Cd metal concentration, and contact time are optimized in batch mode. It also recognizes the contribution of each well-regulated factor. The outcomes of experiments show that the major contribution of the controllable factors for Cd removal is the pH of the solution > stirring time > dose of deposited silt > initial concentration of Cd metal ions. Analysis of Variance (ANOVA) was used to determine significant parameters which contribute to the adsorption process. Results indicate that cadmium removal is mostly influenced by pH 88.17 %, followed by contact time 5.86%, adsorbent dose, 2.41%, and initial metal ion concentration 0.60%. Cadmium adsorption data well fitted to the Langmuir isotherm model. The pseudo-second-order is the best model that explained cadmium adsorption kinetics.

Thailand's long-term GHG emission reduction in 2050: the achievement of renewable energy and energy efficiency beyond the NDC

The sources of greenhouse gas (GHG) emissions in Thailand come from the energy sector, including power generation, transport, industries, buildings, and households. In 2016, the energy sector contributed 77 percent of total GHG emissions. Thailand's energy policies are the essential instrument to deal with GHG emission reduction under the United Nations Framework Convention on Climate Change (UNFCCC). The renewable energy (RE) plans aim at increasing the share of RE in final energy consumption while the energy efficiency (EE) plans aim at improving energy efficiency as well as reducing fossil-fuel consumption. GHG emission mitigation will result in several co-benefits such as increasing energy security and decreasing local air pollutants. Therefore, this study analyzes potentials of GHG emission reduction during 2015–2050 from utilization of renewable energy and increasing energy efficiency using the Long-range Energy Alternative Planning system (LEAP) model. Results include potentials of domestic RE and EE measures to achieve Thailand's nationally determined contribution (NDC). Moreover, it was found that to meet Thailand's first NDC of 20 percent GHG emission reduction target in 2030, targets in the RE plan and the EE plan must be achieved by at least 50 percent and 75 percent, respectively, or targets in the RE plan and the EE plan must be achieved by at least 75 percent and 50 percent. In addition, the extended NDC scenario in 2050 is analyzed in the long-term perspective of Thailand showing 30.4 percent reduction when compared to the BAU. The policy implication includes promotion of energy efficiency, acceleration of the deployment of renewable energy and advanced technologies such as CCS, completion of transmission network for renewable electricity, zoning of biomass sources, and public awareness in climate changes.

Torrefaction of non - oil Jatropha curcas L. (Jatropha) biomass for solid fuel

The use of non-oil Jatropha biomass in the energy mix as a solid fuel offers the most effective ways of utilising such resource. However, available information indicates that biomass has negative inherent properties which lower its fuel value. This negative effect can be improved by slow pyrolysis process called torrefaction where the biomass is heated in the range of 200 °C to 300 °C. In the present investigation the effects of torrefaction temperature on the solid fuel value of different Jatropha biomass materials were determined. Consequently, three types of Jatropha biomass namely; seed cake, stem and fruit cover were considered under five temperature levels (200 °C, 225 °C, 250 °C, 275 °C, 300 °C). Analysis of Variance (ANOVA) revealed that there were significant differences (P > 0.05) in bulk density, hygroscopicity, energy content and ultimate etc. The statistical analysis results indicated that there was biomass type and torrefaction temperature interaction effects on the ultimate analysis, bulk density, hygroscopicity, energy content and energy yield. The interaction effects of the factors under investigation were not observed in mass yield. Increase in torrefaction temperature generally reduced the equilibrium moisture content and volatile matters across the biomass types. However fixed carbon, carbon content, ash content and energy density were increased across the biomass types as the temperature was increased from 200 °C to 300 °C. The torrefied Jatropha seed cake biomass showed relatively enhanced fuel characteristics than the torrefied stem and the torrefied fruit husk when considering the properties under investigation.

Enhancing anaerobic syntrophic propionate degradation using modified polyvinyl alcohol gel beads

Modified polyvinyl alcohol (PVA) beads serve as effective anaerobic microbe immobilization carriers. PVA beads were mixed with different conductive materials, activated carbon, magnetite, and green tuff stone powder. In this study, modified PVA beads were used to investigate the effect of using, promote methane production, and enhance direct interspecies electron transfer (DIET) on the anaerobic syntrophic degradation of propionate, which is an essential intermediate process for generating methane in anaerobic digesters. The batch experiment showed that PVA mixed with activated carbon had the highest methane conversion rate of 72%, whereas the rates for control (sludge) was 61%. Moreover, the lag time during the second and third feedings was shorter by 5-fold than for the first feeding when modified PVA beads were added. The syntrophic propionate degrading microorganisms in the modified PVA beads was Syntrophobacter and Methanobacterium, either Methanoculleus or Methanosaeta. The modified PVA beads hold at least 10 times larger syntrophs than normal PVA. Therefore, composite PVA with conductive materials can promote methane production, accelerate propionate consumption, and enhance electron transfer in related microbial species.

Demonstrating the need to simultaneously implement all water sensitive design methods for aquatic ecosystem health

The practices commonly known as ‘Water Sensitive Design’, or ‘Low Impact Urban Design and Development’, provide a comprehensive package of practices, (building blocks), that respect and work with the natural water cycle and enhance biodiversity. Much previous research has focussed on determining the sustainability gains achieved by the implementation of a narrow range of closely related techniques, such as the installation of at-source devices for stormwater retention and treatment. Other research has investigated the gains for the health of an ecosystem from the reduction of impervious surfaces, or from riparian revegetation, or from the clustering together of buildings. Relationships between these practices and techniques have been observed, but urban developers continue to implement practices such as these in isolation whereas it is suspected that the aquatic ecosystems need all of the practices and techniques to be implemented simultaneously. Without the synchrony of simultaneous implementation, degradation of the ecosystems may still occur and the real cause of it may be missed. The purpose of this research is to monitor, using a biotic index, the ecosystem responses of streams to the simultaneous implementation of as many as possible of these practices (the building blocks) at two different urban densities in paired sub-catchment studies within the Hauraki Gulf catchment of Auckland, New Zealand. Significant differences in the health of the ecosystems of the streams between some treatment and control sub-catchments are observed at both densities. The failure to apply all the techniques (building block methods), or to apply them appropriately in some of the case study sub-catchments, demonstrates a consequent degradation of the ecosystems of the streams that is expected to have negative consequences, not only for local streams but for the marine receiving environment.

Valorization of methane from environmental engineering applications: A critical review

Wastewater and waste management sectors alone account for 18% of the anthropogenic methane (CH₄) emissions. This study presents a critical overview of methanotrophs ("methane oxidizing microorganisms") for valorizing typically discarded CH₄ from environmental engineering applications, focusing on wastewater treatment plants. Methanotrophs can convert CH₄ into valuable bioproducts including chemicals, biodiesel, DC electricity, polymers, and S-layers, all under ambient conditions. As discarded CH₄ and its oxidation products can also be used as a carbon source in nitrification and annamox processes. Here we discuss modes of CH₄ assimilation by methanotrophs in both natural and engineered systems. We also highlight the technical challenges and technological breakthroughs needed to enable targeted CH₄ oxidation in wastewater treatment plants.

Efficient anaerobic digestion of a mild wet air pretreated molasses ethanol distillery stillage: A comparative approach

The effect of a mild, wet air pretreatment and the subsequent anaerobic digestion (AD) was examined on the recovery of a complex and toxic molasses ethanol distillery stillage. The biogas yield and organics removal due to pretreatment were compared with the raw stillage AD. The application of a scoria support in this industrial residue AD process stability was also assessed. Consequently, a statistically significant cumulative specific methane recovery difference (p-value = 0.000) with an almost complete biological oxygen demand (BOD) removal and a significant chemical oxygen demand (COD) reduction, which were 100% and 92% respectively were achieved. Additionally, the biogas recovery rate was hastened due to pretreatment. The application of scoria, whose property has been instrumentally inspected, has helped stabilize the pH in the AD systems. In a comparative approach, this study suggests the energy benefit and an ecofriendly discharge of stillage by the ethanol industry towards sustainability.

Evaluation of Non-Acid-Forming material layering for the prevention of acid mine drainage of pyrite and jarosite

Encapsulation is a typical method used to prevent potential acid mine drainage (AMD) in overburden piles. In this method, Potentially Acid-Forming (PAF) material is covered with either Non-Acid-Forming (NAF) material or alkaline material to minimize water infiltration and/or oxygen diffusion through rock pores. The physical and chemical characteristics and thickness of the NAF material layer are critical factors affecting the successful prevention of AMD. Therefore, this study evaluated the method of NAF material layering using laboratory-scale column leaching tests. NAF layers with a ratio of 25 and 50% were used to cover PAF material containing pyrite and jarosite sourced from the Sangatta and Bengalon mining areas, East Kalimantan. The physical and chemical characteristics of leachate collected from samples watered on a weekly wet-dry cycle were analyzed by kinetic tests over a period of 23 weeks. The results showed a trend of increasing pH values and decreasing sulfate and metal concentrations in the leachate. This study shows that NAF layering is an effective method to prevent or minimize the generation of AMD.

Economic evaluation and comparison of migration paths for the smart grid using two case studies

Today, European utility companies are facing the conversion of their power grids from a previously centrally controlled supply to a then decentralized supply. These changes are necessary to achieve the climate targets. In order to create a decentralized power grid, the integration of modern information and communication technologies (ICT) and other hardware is necessary. On the one hand, the utilities must know which paths they can take to make their power grid intelligent, but on the other hand it is also crucial to know the costs involved. In this contribution we outline a possible model for technological migration paths with a corresponding economic analysis based on German and European case studies.

Determination of the hydraulic conductivity function of grey Vertosol with soil column test

Expansive soils exhibit swell-shrink behaviour in wet-dry periods resulting in distresses on light-weight structures founded on/in them. Therefore, it is essential to investigate the climate-ground interaction when designing structures on expansive soils. Laboratory-based models are preferred to investigate the climatic-ground interaction of expansive soils due to the uncontrollability of the boundary conditions and expenses associated with field monitoring. More flexibility in analysing the climatic-induced hydraulic responses in expansive soils can be achieved by finite element modelling of data from physical model tests. However, these laboratory-based models regularly encounter the effects of boundary flaw, preferential flow paths and entrapped air that needs to be accounted for when numerically simulated. In this study, the authors aim to numerically model the hydraulic responses in an instrumented Vertosol soil column (ISC) under controlled laboratory conditions. The effects of the preferential flow paths and boundary flaws were incorporated into a modified hydraulic conductivity as a practical approach to model the hydraulic responses in ISC. Influence of the entrapped air was rectified by a suitable correction factor. These findings present a practical method for geotechnical practitioners to accurately estimate the suction and volumetric water content profiles in laboratory-based expansive soil model tests.

Novel metric for managing the protection of humanity and the environment against pollution and its adverse effects

Pollution prevention and control are very significant for protecting humanity and the environment against pollution and its adverse effects worldwide. The primary resistance of every country to the occurrence of any of the adverse effects of pollution is a function of the country's pollution prevention & control. Strengthening pollution prevention & control in a country is tantamount to preventing the occurrence of any of the adverse effects of pollution (including any of the pollution-related communicable diseases). Knowing the status of the pollution prevention & control in a country will enable its Government to plan and improve on it. This research work conducted a survey on the extent of availability of pollution prevention & control infrastructure, availability of environmental regulatory agencies and compliance of operating companies to environmental regulations in the Niger Delta. Based on the outcome of the survey, this work invented a novel composite metric titled "Pollution Prevention & Control Index" (PPCI) for measuring the status of pollution prevention & control in a country or region. It is a measure of the protection of the population and the environment against pollution and its adverse effects. Results revealed that the higher the pollution prevention & control index of a country, the smaller the work left undone (or the work to be done) to protect the environment and the population of the country against pollution, its adverse effects and vice versa. Results also showed that the generic pollution prevention & control index of a developed country is higher than that of a developing country.

Modification and characterization of chicken eggshell for possible catalytic applications

Researchers have shown considerable interest in finding a sustainable, low cost, and readily available substitute for the commercial calcium oxide (CaO) catalyst. In this work, raw chicken eggshell was modified by boiling and calcination at 900 °C for 3 h. The x-ray diffraction characterization revealed that while the proportion of CaCO₃ in the raw and boiled samples was found to be 79.3 % and 99.2 % respectively, the CaCO₃ had been converted to 63.8 % CaO and CO₂ in the calcined sample. This was due to the thermal decomposition during calcination. The outcome of the infrared spectroscopy showed that the raw and boiled chicken eggshell presented a similar absorption profile with peaks at 1 394 cm^-1, 873 cm^-1, and 712 cm^-1, which were as a result of the presence of asymmetric stretch, out-of-plane bend, and in-plane bend vibration modes. The major peaks presented by the calcined sample at 3642 cm^-1 can be attributed to the OAH stretching vibration and bending hydroxyl groups present in Ca(OH)₂. The Brunauer-Emmett-Teller surface areas for the raw, boiled and calcined chicken eggshell were found to be 2.33 m²/g, 3.26 m²/g, and 4.6 m²/g respectively, indicating increased catalytic activity of the calcined sample. Overall, boiling was found to have a negligible effect on the chicken eggshell, while high-temperature calcination greatly affected the pore size, surface area, composition, and thermal decomposition profile of the chicken eggshell sample.

Response Surface Methodology optimization of chito-protein synthesized from crab shell in treatment of abattoir wastewater

Abattoir wastewater generated from various meat processing operations in several developing countries pose a serious threat to the environment. Consequently, there is urgent need to reduce the impact of environmental pollution from it. Coagulation techniques have been recommended and used by many researchers successfully in treating wastewater, therefore an investigation of possible use of chito-protein extracted from crab shell (locally sourced) was used as a coagulant for treating abattoir wastewater. Coagulation experiments were carried out using jar-test procedure to investigate the influence of pH, time of settling, temperature and adsorbent dosage for coagulation of BOD, COD, Turbidity and Colour from the wastewater sample. To determine the interaction effect of the various process variables, Response Surface Method (RSM) was used in the optimization of the process variables. To determine the effectiveness of the coagulant, pre and post characterization of the wastewater samples were undertaken, the result of the post characterization of the wastewater sample indicated that most of the water quality parameters except Iron were within WHO standard. The Total Suspended Solid (TSS), for instance stood at 564.6 mg/L and 29 mg/L respectively for pre and post characterisation, the value of 29 mg/L of the post characterization was below the WHO recommended value of 30 mg/L. The predicted responses and the experimental values correlated significantly, an indicator that RSM optimization method used in this study is suitable in modelling the process variables. The result of the study further shows that optimum process variable is dependent on the solution pH (acidic), coagulant dosage of 2–3g, settling time of 25–30 min and operating temperature from 323K to 333K. The coagulant used in this study, when compared with previous studies have shown to have strong potential for use as a coagulant and as an alternative to chemical coagulants in the treatment of abattoir wastewater.

Performance of geotextile-based slow sand filter media in removing total coli for drinking water treatment using system dynamics modelling

In a slow sand filter, a biological layer consisting of alluvial mud and various types of microorganisms grows and attaches to the sand media and forms a matrix called schmutzdecke. Changes to several factors, including the quality of raw water, filtration speed, and the addition of media, affect the performance of the slow sand filter unit in producing treated water. Geotextiles can be equipped to improve the performance of a slow sand filter in removing pollutants. The selection of several factors that affect slow sand filter performance can be used as a starting point for the engineering system to determine the best pattern of performance behavior. This approach was carried out by looking at the dynamic behavior patterns of slow sand filter system performance in treating raw water. This research has not yet been conducted extensively. The dynamic behavior pattern approach to the performance of the slow sand filter unit was used to obtain the behavior model for the schmutzdecke layer on the filter. The system dynamic approach focused on treatment scenarios that can determine the behavior of the slow sand filter system. Several factors were assessed, including temperature, turbidity, nutrient concentration, algal concentration, bacteria and dissolved oxygen. Model simulation results show that the comparison of C: N: P values affected the performance of the schmutzdecke layer in removing total coli. The slow sand filter unit was capable of producing treated water with a total amount of coli equal to 0 on the C: N: P values of 85: 5.59: 1.25, respectively, and a 9 cm geotextile thickness.

Influence of spent mushroom substrate and molasses amendment on nitrogen loss and humification in sewage sludge composting

The present study included lab-scale sewage sludge (SS) composting amended by molasses and spent mushroom substrate (SMS) in 5 L composting reactor system. The influence of molasses and SMS amendment on nitrogen loss and humification of SS composting was evaluated. The results showed that SMS amendment, especially combination with molasses raised composting temperature, increased CO₂ volatilization, promoted organic matter degradation, improve germination index and humification process. The addition of SMS and molasses contain carbohydrates used as carbon source and energy substance by microorganisms could increase microbial activity and ammonia assimilation. In the SMS + molasses treatments, NH₃ volatilization was reduced by 33.1%–37.3% and N₂O volatilization was only 17.8%–25.4% of that in the control treatment, furthermore, the nitrogen loss rate was reduced by 27.2%–32.2%. Consequently, the addition of SMS and molasses improved the compost maturity and reduced nitrogen loss in the SS composting process.

Toilet chemical additives and their effect on faecal sludge characteristics

This study investigated the effects of two mostly improvised chemical additives, calcium carbide and lambda super 2.5 EC (LSEC), on the physico–chemical and microbial characteristics of faecal sludge from toilets. The quality of faecal sludge was assessed before and after application of the chemical additives in an experimental setup of ten different treatment units including a control, and treatment replicates. The initial characteristic of the faecal sludge was slightly acidic with high content of slowly degradable organic matter. The experimental control without additives after 30 days showed reduction in BOD₅, COD, helminth eggs and sludge mass by a maximum of 30%, 34.7%, 99.8% and 55% respectively. Similarly, calcium carbide additive reduced the BOD₅, COD, helminth eggs and the mass of the faecal sludge by 47.4%, 48.3%, 99.6% and 61% respectively. Also, LSEC additive reduced BOD₅, COD, helminth eggs and the mass of the sludge by 40.6%, 47.9%, 95.9% and 58% respectively. The two additives showed significant treatment effect on the faecal sludge although the level of treatment could not meet the regulatory discharge limits for the key quality parameters assessed including sanitisation. The study is still a grey area and more research is recommended to enrich the findings.

Development and comparison of migration paths for smart grids using two case studies

Due to the energy turnaround in German politics, it is necessary to integrate more and more wind and solar energy into the existing energy system. In particular, power generation is changing from a previously centralized to a decentralized structure, which also has consequences for requirements for safe, reliable and efficient grid operation. Generation and utilization characteristics will become more dynamic and flexible in the future. Increased demand for the measurement, control and automation of voltage and electricity will require the further development of grid infrastructure, the expansion of storage capacity and the introduction of information and communication technology (ICT)-based energy management (Appelrath et al., 2012). Utilities therefore need to know what migration paths into the future of a smart energy grid could look like. And this against the background of which technologies have to be installed, in which order this can happen and which dependencies have to be considered. The aim is to create roadmaps to the modern Smart Grid for two case studies. Within the framework of the Green Access project (Projekt Green Access, 2019), and (Flore & Kumm, 2020), a maturity model and, based on this, migration paths were developed for this purpose, which describe a path from one development stage to the next. It describes the necessary development steps that have to be implemented in the context of migration paths. These migration paths have been developed for a specially designed maturity model and describe the technologies used to move from one maturity level to the next. Finally, there will be a comparison of the developed migration paths of the two case studies.

Laboratory evaluation of alum, ferric and ferrous-water treatment residuals for removing phosphorous from surface water

Numerous drinking water plants and agricultural wastewaters generate water treatment residuals (WTR) during coagulation processes. These WTRs may be effective at reducing nutrients entering waterways, thereby decreasing the potential formation of algal blooms. Of the WTRs used in this study, Al-based WTR (Al-WTR) was the most effective achieving a 20 °C cumulative adsorbed concentrations (q_e) after 28 days of desorption of 63–76 mg PO₄/kg Al-WTR depending on the initial spiked concentration. When the isotherm temperature was 5 °C, Al-WTR effectiveness decreased. Ferric chloride WTR (Fe-WTR) was only effective when 0.6 mg/L of PO₄ was spiked to surface water with 0.01 mg/PO₄ stored at 20 °C yielding a 28 day cumulative q_e 5.67 mg PO4/kg Fe-WTR. At 5 °C, the cumulative q_e after extended desorption was 1–4.63 mg/kg Fe-WTR. Ferrous sulfate based WTR (Fe2-WTR) was not capable of adsorbing any additional PO₄ regardless of the spiked concentration or temperature.

Evaluation of emission indices and air quality implications of liquefied petroleum gas burners

Major cities in Nigeria has adopted the use of liquefied petroleum gas (LPG) as their main source for domestic cooking, however, this adoption led to different designs of LPG burners in Nigeria market. The emission indices of these burners and their air quality implications are yet to be ascertain. To solve these problems and fill the data gap, laboratory analysis were carried out on 16 conventional LPG burner heads identified in Nigeria market. The emission factors for Carbon monoxide (CO), Oxide of Nitrogen (NOx), Carbon dioxide (CO₂), Hydrocarbons (HC) and sulphur dioxide (SO₂) on the basis of useful energy delivered were 0.123–21.784 g/MJ_d, 1.973–32.943 g/MJ_d, 73.819–147.639 g/MJ_d, 4.069–171.643 g/MJ_d and 0–0.1644 g/MJ_d while the emission rates were 0.000238–0.1125 g/s, 0.0071–0.2 g/s, 0.1083–0.7 g/s, 0.0117–1.2583 g/s and 0–0.000194 g/s respectively. It was observed that results from the study were within the International Organization for Standardization, International Workshop Agreement 11 and World Health Organization indoor air quality guidelines for human protection.

Determination of malathion's toxic effect on Lens culinaris Medik cell cycle

The present study aimed to determine the toxic effect of malathion pesticide on root growth, cell division and the chromosomal abnormalities frequency using the L. culinaris test. Initially, the lentil seeds were subjected to different doses of malathion (0.0 0.5, 1, 2.5, 5, 10, 15, 20, 25 and 30 mgL^-1) and during 24, 48, and 72 h, the root length was measured. Subsequently, at 72h, the mitotic index, mitotic inhibition, and cellular abnormalities were calculated for all treatments. According to the obtained results, it was visualized that the root growth was inversely proportional to the concentration of malathion at all times of exposure. After 72h of exposure, the lowest values of the mitotic index and inhibition were presented at malathion concentrations 20, 25 and 30 mgL^-1. Additionally, micronuclei cell abnormalities, metaphase sticky chromosomes, split chromosomes, nuclear lesions, irregular anaphase, anaphase bridges, binucleated cells, absence of nucleus and telophase bridge were observed. Finally, Malathion induced mitodepressive and cytotoxic effects in the meristematic cells of the L. culinaris root tip. A high frequency of abnormality was found in the micronuclei, which represented an indicator of a high degree of toxicity at the cellular level.

Bioaugmentation of Vibrio alginolyticus in phytoremediation of aluminium-contaminated soil using Scirpus grossus and Thypa angustifolia

This research analyses the performance of bacteria-assisted phytoremediation of aluminium (Al)-contaminated soil using native Indonesian plants namely, Scirpus grossus and Thypa angustifolia. A range finding test (RFT) was carried out for 14 days to obtain the tolerable Al concentration for both plants. A total of 2% and 5% (v/v) of Vibrio alginolyticus were bioaugmented during the 28-day phytoremediation test to enhance the overall Al removal. Result of the RFT showed that both plants can tolerate up to 500 mg/kg Al concentration. The addition of V. alginolyticus to the reactors resulted in a significant increment of Al removal from the contaminated soil (p < 0.05). Such addition of V. alginolyticus increased the Al removal by up to 14.0% compared with that without-bacteria addition. The highest Al removal was obtained for S. grossus with 5% V. alginolyticus with an efficiency of 35.1% from 500 mg/kg initial concertation. T. angustifolia with 500 mg/kg initial concentration showed the highest removal of 26.2% by the addition of 5% V. alginolyticus. The increase of Al removal by the bioaugmentation of V. alginolyticus was due to the interaction in the plant's rhizosphere. Exudates of both plants provided a good environment for bacteria to live in the root area. Meanwhile, the bacteria increased the bioavailability of Al to be further extracted by plants. Certain mechanisms, such as rhizostabilisation, phytostimulation and phytoextraction, were considered to be the main processes that occurred during the treatment. S. grossus and T. angustifolia displayed promising ability to act as Al hyperaccumulators with bioaccumulation factor values up to 5.308 and 3.068, respectively. Development of the design of the ex-situ soil phytoremediation reactors is suggested as a future research direction because it can significantly enhance the current obtained finding.

Ozone oxidation of wastewater containing trichlorobiphenyl and used transformer oil

Trichlorobiphenyl (TCB) is a persistent toxic organic compound and exerts more hydrophilicity than other polychlorinated biphenyl (PCB) compounds. PCBs have been used on large scale in transformer oil. To observe the strong ozone oxidation effect on the degradation of TCB in aqueous medium, synthetic wastewater was prepared from transformer oil with TCB. Microbubbles ozonation of TCB was done in order to completely oxidize it. A batch treatment system was used for 60 min in glass column with a diffuser at the bottom to convert ozone gas into microbubbles. GCMS analyzed TCB and other toxic compounds before and after the treatment. TCB was reduced to below detection limit during the first 20 min of ozonation. Ethylbenzene and 1-chloroheptacosine were identified after 10 and 20 min, the concentrations of these compounds increased to 1.45 and 3.9 mg/L after 60 min. Alkane with chlorine containing compounds were identified more than any other compounds. The alkanes compounds with chlorine, such as tetradecane 1-chloro, hexadecane 1-chloro, heptadecane 1-chloro, octadecane 1-chloro and nonadecane 1-chloro were found during 60 min of ozonation. Chemical oxygen demand (COD) in the wastewater reduced from 700 to 390 mg/L. Small increase in pH was observed from 7.7 to 8.3. In this study it was concluded that TCB and other pollutants in transformer oil were degraded with ozone dose, 0.05 g/min L in the shortest period of 60 min.

Co-application of biochar and titanium dioxide nanoparticles to promote remediation of antimony from soil by Sorghum bicolor: metal uptake and plant response

Association of titanium dioxide nanoparticles (TiO₂ NPs) and biochar (BC) to assist phytoremediation of Sb contaminated soil was investigated in this study. Seedlings of Sorghum bicolor were exposed to different regimes of TiO₂ NPs (0, 100, 250 and 500 mg kg^-1) and BC (0, 2.5% and 5%), separately and in combination, to investigate the effects on plant growth, Sb absorption and accumulation and physiological response of the plant in Sb contaminated soil. Co-application of TiO₂ NPs and BC had positive effects on plant establishment and growth in contaminated soil. Greater accumulation of Sb in the shoots compared to the roots of S. bicolor was observed in all treatments. Application of BC increased immobilization of Sb in the soil. Using TiO₂ NPs significantly increased accumulation capacity of S. bicolor for Sb with the greatest accumulation capacity of 1624.1 μg per pot achieved in "250 mg kg^-1 TiO₂ NPs+2.5% BC" treatment (P < 0.05). Association of TiO₂ NPs and BC significantly increased chlorophyll a (Chl a) and chlorophyll b (Chl b) contents of S. bicolor compared to the TiO₂ NPs-amended treatments. Results of this study presented a promising novel technique by combined application of TiO₂ NPs and BC in phytoremediation of Sb contaminated soils. Co-application of TiO₂ NPs and BC could reduce the required amounts of TiO₂ NPs for successful phytoremediation of heavy metal polluted soils. Intelligent uses of plants in accompany with biochar and nanomaterials have great application prospects in dealing with soil remediation.

Antimicrobial and coagulation potential of Moringa oleifera seed powder coupled with sand filtration for treatment of bath wastewater from public senior high schools in Ghana

The use of natural plant extracts for treatment of water in some parts of the world has been recorded throughout human history. An example is the use of Moringa oleifera in water purification due to its coagulation properties. However, the efficiency of the treatment systems largely depends on the design of the system and its operation. The aim of this study was to investigate the efficiency of Moringa oleifera seed powder coupled with sand filtration in treating greywater from public senior high schools in the Bolgatanga Municipality and Kasena Nankana West District in the Upper East Region of Ghana. Microbial and physico-chemical properties of greywater collected monthly from the senior high schools was analyzed. Moringa oleifera seed powder was added to raw greywater and then filtered through a sand filter bed. Physico-chemical and microbial parameters of the treated greywater were then analyzed. Mean turbidity, TDS, TSS, T. phosphate and T. nitrogen of the raw greywater was 312.5 ± 76.58 NTU, 445.6 ± 86.77 mg/L, 160.0 ± 28.68 mg/L, 89.3 ± 7.76 mg/L and 30.19 ± 3.63 mg/L respectively whiles average BOD, COD, E. coli and Total coliform were 1032.5 ± 252.40 mg/L, 1736.0 ± 431.59 mg/L, 84.75 x 10⁶ ± 94.01 x 10⁶ N/100ml and 184.25 x 10^s ± 181 x 10⁶ N/100ml respectively. After treatment, there was percentage reduction in turbidity (98.14%), TDS (72.7%), TSS (98.9%), T. phosphate (75.64%), T. nitrogen (43.11%), Total coliform and E. coli (>99%) were recorded. Turbidity was 0.1 NTU and did not meet the WHO standard for drinking water but T. hardness, E. coli and pH was in line with the WHO limit for drinking water. However, BOD increased, and this could be attributed to the significant protein content in the seed of Moringa oleifera. Moringa oleifera seed powder coupled with sand filtration demonstrated the antimicrobial and coagulative potential as turbidity and E. coli of the raw bath greywater from the senior high schools reduced by >98% and >99.99% respectively after treatment.

Role of local town planning authorities in building collapse in Nigeria: evidence from Enugu metropolis

The current spate of building collapse in Nigeria has continued to attract research efforts to unravel the causes and possible remedies. Although cases of building collapse in Nigeria has been associated with several factors, those factors associated with building plan approval process have not adequately investigated, especially in a rapidly expanding colonial city of Enugu. The study investigated the role of local town planning authorities in the increasing cases of collapsed buildings in Nigeria using Enugu as a case study. A well-structured questionnaire was administered to the three Chief Town Planners in the three planning approval offices and oral interviews randomly selected 30 developers in ongoing construction projects within Enugu metropolis were conducted. Using content analysis and descriptive statistics the data collected were analyzed. It was observed that due to poor staffing and lack of engagement of building professionals, the planning approval authorities were not effective in scrutinizing, vetting and evaluating building drawings submitted for approval as well as in supervising and monitoring the level of compliance of buildings under construction with the operational building codes and bye-laws in the study area. The study concludes that these lapses in the roles of local building approval authorities can contribute to the increasing cases of collapsed buildings in Enugu Metropolis. It recommends that government should take proactive steps by engaging the right number of building professionals in her planning approval offices and ensuring strict enforcement of the existing physical development legislation and punishment of offenders.

Effectiveness of the mixture of nopal and cassava starch as clarifying substances in water purification: A case study in Colombia

Aluminum sulfate is one of the most used chemical coagulants in the world, but research has shown that high concentrations of aluminum in the body are associated with neuropathological conditions. Because of this, different alternatives have been evaluated such as natural coagulants, which are considered safe for human health and contain fewer contaminants than chemicals due to their biodegradation properties. The main objective of this study was to evaluate the efficiency of mixing nopal mucilage and cassava starch for turbidity removal in water purification. In this paper, test jars and the treatment equipment (TA-scale FQ-005/PE manufactured by Generatoris SA de CV of Mexico) was applied in order to measure turbidity and pH parameters before and after the process of coagulation–flocculation, which was applied to water from the Magdalena River in Colombia. Samples from two sampling periods were assessed. One was evaluated during the rainy season and the other was evaluated without precipitation (drought) with initial turbidities of 316 NTU and 80 NTU, respectively. It was found that aluminum sulfate as a coagulant reference obtained better turbidity removal results (up to 99%) as compared to nopal (up to 60.4%), and nopal–starch combination of cassava (up to 67%), indicating that this mixture increases the effectiveness of natural coagulants used individually. Our results indicate that this should be considered as an alternative in the water purification process.

Improved Moth-Swarm Algorithm to predict transient storage model parameters in natural streams

Transient storage model (TSM) is the most popular model for simulating solutes transport in natural streams. Accurate estimate of TSM parameters is essential in many hydraulic and environmental problems. In this study, an improved version of high-level Moth-Swarm Algorithm (IMSA) was used to predict the TSM parameters. First, the performance of the improved model was successfully assessed through several benchmark functions. Next, a series of 58 measured hydraulic and geometric datasets was used to validate the model. The data were divided into two series randomly, 38 datasets were selected for derivation and the remaining 20 datasets were used to verification. Then the results of IMSA were compared with other algorithms proposed by previous researchers. Two statistical indices of root mean square error (RMSE) and coefficient of correlation (CC) were employed to evaluate the performance of the model. The results showed that despite the high complexity and uncertainty associated with the dispersion processes, the IMSA algorithm could accurately predict the TSM parameters.

Assessment of Cd(II) adsorption capability and mechanism from aqueous phase using virgin and calcined lignin

Herein, to assess the adsorption capability and elucidate the adsorption mechanism of Cd(II) from the aqueous phase, virgin lignin (Lig) and calcined lignin (Lig200, Lig400, Lig600, Lig800, and Lig1000) were prepared. The characteristics, including specific surface area and pore volume of adsorbents, were investigated, and the adsorption capability along with the effect of temperature, contact time, and pH on the adsorption of Cd(II) were evaluated. The characteristics of the adsorbent surface were related to the adsorption capability of Cd(II) from the aqueous phase, and the correlation coefficients between the adsorbed amount and specific surface area and total pore volumes were 0.872 and 0.960, respectively. Moreover, the amount adsorbed using Lig800 (91.3 mg/g) was higher than that using other adsorbent samples. The adsorption mechanism was elucidated to investigate the binding energy and elemental distribution before and after Cd(II) adsorption. Finally, the desorption capability of Cd(II) from Lig800 using a hydrochloric acid solution was demonstrated. Results obtained herein suggest that Lig800 is a potential candidate for the removal of Cd(II).

Solid waste quantification and characterization in university of Nigeria, Nsukka campus, and recommendations for sustainable management

Quantification and characterization of municipal solid waste are the bases for a proper solid waste management planning but the needed collection, transportation, characterization and disposal are grossly under-investigated and scarcely implemented in Nigerian Universities. This study, therefore, quantified and characterized the waste generated in the university of Nigeria, Nsukka campus using ASTM D5231-92 method, and recommended possible integrated solid waste management strategies for a sustainable management of the waste. The average daily solid waste generation in the university was estimated to be 2,218.66kg during the 6-month study period from 24^th February to 18^th August in 2017/2018 academic session with organic and polythene representing the largest portion at 32.36% and 34.29%, respectively. Glass/bottle, textiles/leather, rubber, wood, e-waste, sanitary, medical, polystyrene food pack and metal wastes represented 0.97%, 2.69%, 0.28%, 0.82%, 0.98%, 2.16%, 0.16%, 1.04% and 1.67%, respectively. The campus has a per capita solid waste generation rate of about 0.06kg/day. About 96.58% of the total waste is recyclable, and has about 51.85% biomass potential. Analysis of variance showed that differently dominated areas of the campus have different quantities and compositions of wastes mainly due to significant variation of organic and polythene components across the differently dominated areas. The barriers against effective solid waste management and recommendations for integrated solid waste management strategies were made to include solid waste generation reduction, re-usage, recycling, composting, and proper training and provision of incentive and other fiscal policies.

Evaluating hypoxia alleviation through induced downwelling

Hypoxia, a condition of low dissolved oxygen concentration, is a widespread problem in marine and freshwater ecosystems. To date, prevention and mitigation of hypoxia has centered on nutrient reduction to prevent eutrophication. However, nutrient reduction is often slow and sometimes insufficient to remedy hypoxia. We investigate the utility of a complementary strategy of pumping oxygenated surface water to depth, termed induced downwelling, as a technique to remedy hypoxia in the bottom water of marine and freshwater ecosystems. We introduce simple energy-based models and apply them to depth profiles in hypoxic estuaries, lakes, and freshwater reservoirs. Our models indicate that induced downwelling may be ~3 to 10² times more efficient than bubbling air, and 10⁴ to 10⁶ times more efficient than fountain aerators, at oxygenating hypoxic bottom waters. A proof-of-concept downwelling field experiment highlighted potential advantages and shortcomings. We estimate that regional-scale downwelling for continual hypoxia avoidance would require 0.4 to 4 megawatts per cubic kilometer of water (depending on local conditions), or 50 to 500 US dollars per hour per cubic kilometer of water (assuming 125 USD MWh^-1 of electricity). Many potential side effects of downwelling are discussed, each of which would need to be explored and assessed before implementation. Downwelling does not replace nutrient management strategies, but under some circumstances may provide an efficient means to augment these strategies.

Phosphorus removal from secondary wastewater effluent using copper smelter slag

This study investigated the use of copper smelter slag for the removal of phosphorus from secondary wastewater effluent through batch tests. The media was physically and chemically characterized and showed presence of Fe2O3 (45.22%), SiO2 (14.98%), Al2O3 (3.21%), CaO (1.99%), SO3 (1.77%) and MgO (1.33%). Scanning electron microscopy monographs revealed smooth and flat surface and no heterogeneity on the surface of the slag with visible micro pores before the experiment and less visible after the experiment. The point of zero charge of the media was 5.0. Equilibrium was reached after 4 h at 29.5 ± 0.71% phosphorus removal efficiency and media dosage of 0.4/100 mL. The kinetic data was best described by Pseudo second order equation. More than one mechanisms were involved in the adsorption of phosphorus onto copper smelter slag as suggested by multi-linearity of intra particle diffusion model. Ninety seven percent (97.5 ± 0.0%) removal efficiency was achieved at an equilibrium dosage of 160 gL-1. The equilibrium isotherm was described better by Langmuir equation with observed maximum adsorption capacity of 0.16 mg P g-1 media and the experimental maximum adsorption capacity was 0.26 mg P g-1 media. Regeneration studies showed low performance with maximum efficiency of 11.7% revealed during the first regeneration trial therefore low practical benefits. Copper smelter slag is a poor adsorbent for phosphorus and further studies on the media should be conducted.

Clean vehicles, polluted waters: empirical estimates of water consumption and pollution loads of the carwash industry

Carwash stations use large volumes of water and release harmful chemicals into the environment through their operations. While a significant body of literature has focused on exploring water use in the carwash industry, none has provided comprehensive information on both the pollution loads of the wastewater emanating from this industry and water consumption. Understanding how much water is used and the pollution loads of wastewater from this industry is useful to ensure adoption of water conservation measures and design wastewater recycling systems given the dwindling freshwater resources globally. This study estimated the freshwater quantities used to wash different vehicle types and the pollution loads of the resulting wastewater in the Kumasi Metropolis. Seven proxy carwash stations were purposively selected and monitored to estimate the water used to wash six different categories of vehicles. Composite wastewater samples from three carwash stations were analysed for concentrations of different contaminants which were used to compute pollution loads. Using R software, one-way ANOVA with Tukey's (HSD) post-hoc testing and 2-sample t-test at 95% confidence interval were employed to test statistical differences. After an 8-week monitoring campaign involving 3,667 vehicles, the study showed that average water used for each vehicle type were in the order: Motorbike - 97L (95% CI: 90-103L); Salon car - 158L (95% CI: 154-161L); SUV - 197L (95% CI:191-203L); Buses/Coaches - 370L (95%CI:351-381L); Articulated truck 1,139L (95% CI:916-1,363L); Graders/Loaders - 1405L (95% CI:327-2,483L). Overall, the carwash industry in the Metropolis uses about 1000m³ of freshwater daily and discharges the resulting wastewater into waterways untreated. The wastewater has a low Biodegradability Index (0.3-0.4) and is characterized by a mildly alkali pH (7.6-8.6) with high levels of Sulphates (40.8-69.8 mg/L), COD (990-1413 mg/L), TSS (1260-3417 mg/L) and E. coli (2.3-4.7 × 10³ CFU/100mL). Pollution loads of BOD and COD were up to 2tons/year and 6tons/year respectively. Stipulated effluent discharge guideline values were mostly exceeded - in some cases by up to 68 times. To avert the unbridled wastage of freshwater, the study recommends enforcement of wastewater recycling for all carwash stations and promulgation of a tax system that rewards stations that recycle wastewater and surchages those wasting freshwater.

Tung oil as an effective modifier for sulfur polymer cement and its performance in galvanic waste encapsulation

The data on the performance of sulfur polymer cement crosslinked with tung oil polymerization modifier are presented. Specimens of sulfur polymer cement (SPC) were prepared with different doses of tung oil in amounts of up to 8.85% of the sulfur mass. The obtained SPCs were used as binders to encapsulate two galvanic wastes differing in their toxic metal composition: waste I and waste II with loadings of approximately 25 and 50% of the composites' mass, respectively. For comparative purposes, appropriate samples of the SPCs and their composites with galvanic wastes were obtained using very similar doses of dicyclopentadiene sulfur modifier. Waste II was also encapsulated using SPC, in which a mixture of tung oil and dicyclopentadiene in a 1:1 weight ratio was used as the modifier. Crosslinking of the tung oil to the SPC matrix was assessed by FT-IR. The obtained SPCs and their composites with galvanic wastes were characterized by SEM and tested for water sorption capacity, compressive strength and metal leaching toxicity using TCLP and EN standards. The effectiveness of the tung oil binding to the SPC network was evidenced by the complete disappearance of methine C–H stretching vibrations at 3010 cm⁻¹ and the double bond –C=C– wagging vibrations at 990 cm⁻¹ in the FT-IR spectrum after processing with sulfur. SEM observations revealed that all the specimens prepared with dicyclopentadiene had a glassy-like fracture surface and also showed fewer cavities and defects in cements and composites when compared to their counterparts prepared with tung oil. The water sorption capacities of all the specimens were below 1%, where the values of those prepared with the tung oil were two to three fold higher than the values of their counterparts prepared with dicyclopentadiene. The pH of the TCLP leachates was in the range of 2.75–2.98, and a decreasing trend in the pH value was found with an increasing modifier dose. The TCLP leachate pH from the waste I monoliths with dicyclopentadiene were generally lower by 0.1–0.35 when compared to the corresponding monoliths with tung oil. The toxic metals immobilization order revealed from the TCLP test (leachate pH around 2.85) is Cd > Sr ≥ Zn > Cu > Ni > Cr > Pb, while the resulting order from the EN test, due to a higher leachate pH of about 5.9, follows Cd > Pb > Zn > Cu ≥ Ni > Sr > Cr. An increased tung oil dose from 2 to 8.85% enhanced the SPC compressive strength by three to four fold, while the same increase of the dicyclopentadiene dose led to an increase of this parameter for less than two fold. The addition of galvanic wastes to the SPCs resulted in a further increase in compressive strength for the corresponding SPC samples.

Natural rubber modification as a pre-vulcanized latex impregnated with TiO2 for photo-catalytic degradation of gaseous benzene

Photocatalytic oxidation purposes an economical and environmental friendly process to remove benzene from indoor air pollution. However, the process efficiency is primarily dependent on catalytic-film. The main purpose of this study is to synthesize pre-vulcanized latex impregnated with TiO2 (PVL-TiO2 thin film) from natural rubber to be used in photo-catalytic oxidation for benzene removal in a reactor. PVL-TiO2 thin films were synthesized for 3 different dosages of TiO2, which were 5%, 15%, and 25% The outcome of this study offers the new application of modified natural rubber in terms of environmental and health care protection. Morphology of the synthesized films was analyzed by SEM. The results showed that TiO2 particles could be well dispersed all over the surface of the film, in which the best distribution could be found for the PVL-TiO2 15% thin film. Tensile stress of the films was analyzed using ASTM D412. Results showed that the stress of the films got higher with the increasing amount of TiO2 content. This indicates that TiO2 strengthened the PVL-TiO2 film because the uniformly distribution of TiO2 on the inner surface increased the strength of the film. The decomposition of PVL and PVL-TiO2 thin films was analyzed using thermo gravimetric analysis. The maximum weight loss rates in the range of 1.536-1.145 wt%/°C attained at between 380 - 382 °C TiO2 particles enhanced thermal stability of PVL-TiO2 thin films due to the high decomposition temperature of its properties and also acted as barrier for the heat transfer of the films. Specific surface area (SSA) of the films was analyzed using Brunauer-Emmett-Teller. Specific surface area increased as the increasing content of TiO2, which corresponded to the morphology analysis by SEM. The analysis of chemical functional group of thin films was performed using ATR-FTIR. The results of Crystal identification using XRD clearly showed good attachment of rutile TiO2 on the films. Finally, results of absorbance spectrums and band gap energy showed that PVL not only peg TiO2 particles but also reducing band gap energy which induced by S and ZnO. Therefore, PVL-TiO2 thin films could be used under visible light condition. The films were then used in the study of benzene removal in annular reactor. The highest removal efficiency (83%)for the PVL-TiO2 15% thin film was obtained. Comparing to the maximum removal efficiency for PVL film (28%), roughly 60% increase in efficiency was achieved. The PCO kinetics were well fit by a first order Langmuir-Hinshelwood model. The calculation of oxidation rate and percentage of residual intermediates indicated that accumulation of residual intermediates can occur on the active site and the gas phase, resulting in increasing of residual intermediates. The successful synthesis of PVL-TiO2 thin film provides new opportunity to use natural rubber in terms of environmental and health care protection.

Behavior of schmutzdecke with varied filtration rates of slow sand filter to remove total coliforms

The previous research showed that slow sand filtration (SSF) can remove the total coli by approximately 99% because of the schmutzecke layer in the filter. The presented study aimed to complete the previous research on SSF, especially on the schmuztdecke layer mechanism, to remove total coli. Total coli is a parameter of water quality standard in Indonesia, and the behavior of schmutzdecke affects the total coli removal. In the present study, the raw water from Amprong River was treated using horizontal roughing filter (HRF) and SSF. The variations in SSF rate used were 0.2 and 0.4 m/h. Total coliforms were analyzed using the most probable number test, and schmutzdecke visualization was conducted through scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM–EDX). The best coliform concentration in water treated by the combination of HRF and SSF was 4,386 colonies per 100 mL of sample using the filtration rate of 0.2 m/h, and its removal efficiency was 99.60%. However, the quality of water treated by the combination of HRF and SSF did not meet the drinking water quality standard because the removal of total coli must be 100%. The SEM–EDX visualization results in schmutzdecke showed that the average bacteria in the schmutzdecke layer were small, white, opaque, and circular, with entire edge and flat elevation. The Gram test results showed that the schmutzdecke bacteria consisted of Gram-positive and Gram-negative bacteria with basil as the common cell form.

Kinetic evaluation of a partially packed upflow anaerobic fixed film reactor treating low-strength synthetic rubber wastewater

A bench-scale model of a partially packed upflow anaerobic fixed film (UAF) reactor was set up and operated at five different hydraulic retention times (HRTs) of (17, 14, 10, 8, and 5) days. The reactor was fed with synthetic rubber wastewater consisting of a chemical oxygen demand (COD) concentration of 6355-6735 mg/L. The results were analyzed using the Monod model, the Modified Stover-Kincannon models, and the Grau Second-Order Model. The Grau Second-Order model was found to best fit the experimental data. The biokinetic constant values, namely the growth yield coefficient (Y) and the endogenous coefficient (K_d) were 0.027 g VSS/g COD and 0.1705 d^-1, respectively. The half-saturation constant (K_s) and maximum substrate utilization rate (K) returned values of 84.1 mg/L and 0.371 d^-1, respectively, whereas the maximum specific growth rate of the microorganism (μ_max) was 0.011 d^-1. The constants, U_max and K_B, of the Stover-Kincannon model produced values of 6.57 g/L/d and 6.31 g/L/d, respectively. Meanwhile, the average second-order substrate removal rate, k_s(2), was 105 d^-1. These models gave high correlation coefficients with the value of R² = 80-99% and these indicated that these models can be used in designing UAF reactor consequently predicting the behaviour of the reactor.

Study of sweetened seawater transportation by temperature difference

This study evaluates the vapor transportation by transmission pipelines during seawater desalination. This study seeks to reach a high rate of water transportation during desalination. Hence, the results obtained from this research are closer to reality than other analyses. Other benefits of this research include increasing efficiency, studying the element-to-element transmission, and considering flow as a compression case. The water desalination system comprises three parts of evaporation, transportation, and condensation. In the transportation part, equations of continuity, momentum, and energy are implemented, and the temperature of the vapor is calculated at the beginning of the condensation pipe. Other achievements of this study include the division of transportation lines to small elements and the implementation of vapor condensation in transportation lines. This study used pipelines with diameters of 1, 2, and 4 m to transmit vapor to Ramsar city and the heights of Takhte Soleiman, 16 km away from the city with the elevation of 2000 m. The results show that diameter, transportation length, and temperature differences are, respectively, the most influential factors on the efficiency of sub-atmospheric vapor transportation. The outcomes of this study were presented as the outflow of condensed water at the destination. Considering the margin of safety in calculations, it was scientifically proved that the results obtained in this study were approximately 10% more than results derived from other studies in the literature that are based on the incompressibility of fluids.

Exergetic sustainability and economic analysis of hybrid solar-biomass dryer integrated with copper tubing as heat exchanger

The aim of this study is to present a new hybrid solar-biomass dryer and carry out thermal analysis based on energy and exergo-sustainability analysis considering all the available exergy stream of solar radiation, air stream through the collector, and exergy of the moisture in the product. The research also presented the environmental impact and economic analysis of using the dryer. Performance evaluations show that at collector efficiency of 20.81%–21.89 %, the developed solar dryers can save between 10 – 21hrs of drying time in drying 5 mm thick plantain slices to 15 % moisture content from initial moisture content of 66 % w.b when compared to drying under the open sun. The improvement potential ranged from 0.036 to 20.6W while the waste exergy ratios and sustainability index ranged from 0.38 - 0.55 and 2.3–6.11 respectively. Application of the solar dryers can save between 44 -3074 of CO₂ entering the atmosphere per year while 2.94 to 205.43$ could also be saved at 10–100% rate of usage when compared to diesel fired dryer. The total energy consumption for drying ranges between 5.52 and 35.47 MJ, while the specific energy consumption ranged from 4.3 to 26.2 kWh/kg. The exergy efficiency ranges from 5.6 – 95.13 % during the sunshine hours.

Electrochemical oxidation of acetaminophen and its transformation products in surface water: effect of pH and current density

Several studies have been conducted worldwide to develop effective and affordable methods to degrade pharmaceuticals and their metabolites/intermediates/oxidation products found in surface water, wastewater and drinking water. In this work, acetaminophen and its transformation products were successfully degraded in surface water by electrochemical oxidation using stainless steel electrodes. The effect of pH and current density on the oxidation process was assessed and the oxidation kinetics and mechanisms involved were described. Additionally, the results were compared with those obtained in acetaminophen synthetic solutions. It was found that conducting the electrochemical oxidation at 16.3 mA/cm² and pH 5, good performance of the process was achieved and not only acetaminophen, but also its transformation products were totally degraded in only 7.5 min; furthermore, small number of transformation products were generated. On the other hand, degradation rates of acetaminophen and its transformation products in surface water were much faster (more than 2.5 times) and the reaction times much shorter (more than 4.0 times) than in synthetic solutions at all current densities and pH values evaluated. At pH 3 and pH 5, greater soluble chlorine formation due to the higher HCl amount used to acidify the surface water solutions could enhance the degradation rates of acetaminophen and its transformation products. However, constituents of surface water (ions and solids) could also have an important role on the oxidation process because at pH 9 (non-acidified solutions) the degradation rates were also much greater and the reaction times were much shorter in surface water than in acetaminophen synthetic solutions.

Biosorption of Hg (II) from aqueous solution using algal biomass: kinetics and isotherm studies

The present work investigated the ability of algal biomass Chlorella vulgaris to remove mercury from aqueous solutions. The mercury biosorption process was studied through batch experiments 35 °C temperature with regard to the influence of contact time, initial mercury concentration, pH and desorption. The maximum adsorption capacity was registered at pH 6. The adsorption conduct of Hg(II) was defined by pseudo second order well rather pseudo first order as the experimental data (q_e) come to an agreement with the calculated value. The kinetics of adsorption was fast and a high capacity of adsorption occurred within only 90 min. The adsorption data were signified by many models but Langmuir (q_max = 42. mg g⁻¹) & Freundlich fitted well having regression coefficients near to unity. The thermodynamic parameters were also suited well as negative value of free energy cope up to spontaneity, positive value of the randomness described by ΔS attributed to affinity of Hg⁺² towards algal bioadsorbant and high positive value of heat of enthalpy designates that the adsorption process is expected due to robust interactions between the Hg(II) ions and various functional groups on surface of algal bioadsorbant. Field emission scanning electron microscopy integrated with energy dispersive X-ray spectroscopy analysis before and after adsorption of Hg(II) reveals the adsorption of metallic ions over the surface. FTIR study supported the existence of various functional groups (carboxylix, amines, hydroxyls, amides etc.) helped in adsorption. Continuous adsorption desorption experiments proved that algal cells was excellent biosorbents with potential for further development.

Adsorption of the methyl green dye pollutant from aqueous solution using mesoporous materials MCM-41 in a fixed-bed column

In this study, a Methyl Green (MG) dye pollutant was separated by Mobil Composition Matter No. 41 (MCM-41) in a fixed-bed continuous column with investigated three parameters, namely a bed height (2-6 cm), initial MG concentration (10-30 mgL^-1) and a process flow rate (0.8-1.6 mL min^-1). Results indicated that the highest bed capacity of 20.97 mg/g was obtained with respective to optimal values such as; 6 cm for a column height, 0.8 mL min^-1 for flow rate, and an initial MG concentration 20 mgL^-1. Furthermore, a quantity of the adsorbed pollutant decreased as the flow rate increased, while increasing the initial MG concentration yielded the opposite effect. The column apparatus was performed properly at the low flow rate, whereas both the breakthrough and exhaustion time increased with the bed depth. Thomas and Yoon-Nelson models were applied for predicting the breakthrough curves and calculating the characteristic factors of the laboratory fixed-bed adsorption column, which were beneficial for process design. Based on regression coefficient analyses, results of employing the Yoon-Nelson model was found to be superior to the Thomas one. Breakthrough performance indicated that MCM-41 was suitable for applications in continuous adsorption regimes for MG dye. The mesoporous MCM-41 was recovered effectively by calcinations and employed again for four times in the continuous system successfully.