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Rivers adjacent to industrial zones usually suffer from severe pollution issues. Industrial wastewater that has undergone sewage treatment processes may be legally discharged into rivers under water quality permits. Previous studies have frequently employed isotopic tracers to identify potential contaminants for pollution control. Conventional radiogenic isotopes utilized in tracing studies cannot discern whether the source is untreated (primary) industrial wastewater, which can have serious impact to the environment. By analyzing the iron (Fe) and molybdenum (Mo) isotopic compositions in original industrial wastewater and treated effluent, this study aims to investigate whether the heavily polluted Agongdian River is contaminated by the untreated wastewater. Based on the results from this study, the original industrial wastewater exhibits higher concentrations of metallic elements and heavier Fe and lighter Mo isotopic compositions, compared to the treated effluent. Consequently, it appears that Agongdian River water indeed exhibits evidence of untreated industrial wastewater. Furthermore, the volume of original industrial wastewater entering the river can be estimated from these results. This research offers a more precise and accurate approach to monitor potential industrial wastewater pollution in natural water bodies, contributing to the goal of environmental protection and sustainable development. [ABSTRACT FROM AUTHOR]

Industrial sludge continues to increase in quantity with the development of industry. Therefore, how to effectively treat industrial sludge continues to be an environmental focus around the world. Due to the high calorie content of industrial sludge in Taiwan, most of the sludge is incinerated for simplicity and convenience. However, this incineration causes environmental pollution and cannot effectively reuse the industrial sludge. In this study, we investigated the feasibility of lightweight aggregates produced from water treatment sludge (WTS) mixed with industrial sludge. The industrial sludge was obtained from three industrial zones in Taiwan. The lightweight aggregate materials were prepared by mixing WTS with 7.5%, 15.0%, or 22.5% of industrial sludge as a secondary ingredient. The chemical composition analyses revealed that the ternary phase diagrams of the chemical components were within the range recommended by C.M. Moreover, Riley indicated that the ingredients could expand. The sintering experiments were conducted in two stages. Stage I served to determine the optimal sintering temperature, while Stage II produced lightweight aggregates at the optimal sintering temperatures after 5, 10, or 15 min of preheating. The results indicated that an increase in preheating time increased the particle density of the lightweight aggregates but decreased the water absorption ratio, because increasing preheating time causes more gases to escape, resulting in aggregates that could not produce sufficient gas to support expansion during the sintering stage. The sintering results of the lightweight aggregates showed that their particle density was between 0.5 and 1.4 g/cm3, which met the requirements of the specification. Their water absorption rate was below 21%, which was roughly in line with the recommendations of the specification. When the amount of industrial sludge added was less than 22.5%, the lightweight aggregate was sintered successfully, which is suitable for engineering applications. The industrial sludge experienced a loss of between 50% and 70% on ignition, resulting in pores and cracks that were observed on the surfaces of the lightweight aggregate. Based on the energy required to sinter lightweight aggregates, a greater loss on ignition indicates the conversion of more materials into heat energy. Therefore, the use of industrial sludge in lightweight aggregates not only provides ways to reuse industrial sewage waste but also reduces the consumption requirements for sintering lightweight aggregates, thereby achieving energy-saving and carbon-reduction goals. [ABSTRACT FROM AUTHOR]

With recent increases in environmental awareness, the circular economy concept, which involves turning waste into usable products, has gradually become widely accepted. Spent mushroom substrate (SMS) is an agricultural waste that lacks recycling channels in Taiwan. This study explored the feasibility of simultaneously recycling two completely different types of waste: spent mushroom substrate (SMS), an agricultural waste, and electric-arc furnace dust (EAFD), an industrial waste. Specifically, SMS was used to replace metallurgical coke as a reducing agent for EAFD, which underwent carbothermic reduction to recycle valuable metallic Zn. The results showed that if SMS and EAFD were mixed at a C/O ratio of 0.8, the degree of Zn removal achieved 95% at 1100 °C, which is 150 °C lower than the reduction temperature of the EAFD-coke mixture (due to volatile matter (VM) in SMS). For the reduction of ZnO in EAFD, with the assistance of VM in SMS, the C/O ratio can be decreased from 0.8 to 0.16 at 1300 °C, achieving a high degree of Zn removal over 95%. In addition, the torrefaction of SMS increased the fixed carbon content and improved the Zn productivity at the same C/O ratio, reaching almost the same productivity as the coke sample (SMS torrefaction = 500 °C, C/O = 0.8, reduction = 1200 °C, Zn removal~99%). Finally, CO2 emission reductions from the use of SMS were also estimated. [ABSTRACT FROM AUTHOR]

Enhanced weathering is a negative emissions technology based on the accelerated weathering of alkaline minerals. Such materials can be reduced to a fine powder and applied to land sinks to maximize the area exposed for reaction with rainwater and dissolved CO2. The carbon is captured in the form of bicarbonate ions in the runoff, which ultimately carries it to the ocean for virtually permanent sequestration. Enhanced weathering has been demonstrated in proof-of-concept laboratory and field tests, but scale-up to a level that delivers significant CO2 removal is still an engineering challenge that requires a system-level perspective. Future enhanced weathering networks should be planned like industrial supply chains, taking into account constraints in the supply of alkaline minerals and the availability of land sinks. Optimization of such networks should also take into account techno-economic uncertainties that are inherent in any emerging technology. To fill this research gap, this work develops a fuzzy mixed-integer linear programming model for optimal planning of enhanced weathering networks. The model is capable of handling multiple conflicting objectives and accounting for system uncertainties. The use of the model is illustrated with two case studies. First, a pedagogical example is solved; then, the model is demonstrated for a realistic scenario which shows that 0.69% of Taiwan's CO2 emissions can be offset by the use of blast furnace slag for enhanced weathering. [ABSTRACT FROM AUTHOR]

Growing concern about circular bioeconomy and sustainable development goals (SDGs) for the valorization of food waste has raised public awareness since 2015. Therefore, the present study focused on the promotion policies and regulatory measures for the valorization of mandatory recyclable food waste from industrial sources in Taiwan, including the animal/plant production farms and food-processing plants. According to the official data on the annual statistics during the period of 2015–2019, it showed that the food waste from alcoholic beverage manufacturers (i.e., lees, dregs, or alcohol mash) and oyster farms (i.e., waste oyster shell) accounted for about half (about 250,000 metric ton) of industrial food waste generation in Taiwan. In order to effectively reduce the burdens on incinerators/landfills and their environmental impacts, the central governing agencies jointly promulgated some regulatory measures for promoting the production of biobased products from the industrial food waste valorization like animal feed, soil fertilizer, and bioenergy. These relevant acts include the Waste Management Act, the Fertilizer Management Act, the Feed Management Act, and the Renewable Energy Development Act. In addition, an official plan for building the food waste bioenergy plants at local governments via anaerobic digestion process, which was estimated to be completed by 2024, was addressed as a case study to discuss their environmental and economic benefits. [ABSTRACT FROM AUTHOR]

Phthalate esters (PAEs) are fat soluble synthetic chemicals, usually regarded as plasticizers for being added in numerous plastic products. Thus, environmental and health hazards of PAEs are associated with increasing plastic pollution. In this study, PAEs from sludge samples collected from water, sewage, and industrial treatment plants (N = 17) were analyzed using Gas Chromatography/Mass Spectrometry. Microplastics (MPs) were also quantified and correlated with PAEs. Results showed the highest average PAE concentrations in sewage treatment plants. The greatest ΣPAEs concentration were found in sewage treatment plant (STP4) with 32,414 μg/kg dw, while the lowest found in water treatment plant (WTP3) with 2062 μg/kg dw. Among different PAEs, di-(2-ethyl hexyl) phthalate (DEHP) contributes the highest. Similarly, DEHP, di-n-octyl phthalate (DnOP) and diisononyl phthalate (DiNP) significantly correlated with the total PAEs indicating their large contribution to sludge contamination. The abundance of microplastics in sludge ranged between 1 and 7 MP/g, highest at ITP6, but not detected in some stations. While microplastics may potentially increase PAEs, there was no significant relationship between ΣPAEs and MP abundance. The estimated human daily intake of DEHP and di-n-butyl phthalate (DnBP) when contaminated sludge be used showed low toxicological risks to exposed adults. This research presents the sludge characteristics, PAEs, and microplastic concentrations in different wastewater treatment plants in Taiwan. PAE contamination was highly contributed by domestic and industrial wastes shown by their significant amounts in STP and ITP. Results further provide evidence for potential sludge recycling (WTP sludge) and application to soil. [Display omitted] • The ΣPAEs concentration ranged between 2062 and 32,414 μg/kg in sludge samples. • DiNP, DnOP, DEHP contributed >94% of PAEs in sludge samples, except ITP2 and ITP6. • Low toxicological risk of WTP sludge shows possible disposal and soil application. [ABSTRACT FROM AUTHOR]

Due to industrialization and economic development, urban expansion in St. Petersburg (Russia) has swelled its solid waste generation. The current waste management system does not meet the city's needs. Fundamental changes are required to accelerate its sustainability transition to achieve the 2030 UN's Sustainable Development Goals. This article critically evaluates and analyzes the existing situation of waste management in St. Petersburg and its role in promoting digitalization-based circular economy. Challenges in waste recycling that prevent it from reforming its waste management are identified. Lessons drawn from Taiwan's prowess in resources recovery are presented to inspire a transformation of its waste sector towards a digitalization. The implications of digitalization on the city's waste recycling industry are elaborated. Before applying digitalization, St. Petersburg encountered challenges such as a lack of proper infrastructure in waste management, low public participation and environmental awareness, technological gaps, and insufficient coordination among its institutions. As one of the world's leaders in waste recycling (65%), Taiwan was selected as a role model for St. Petersburg in improving its waste management. The Island's daily per capita rate decreased by 96% to 0.4 kg in 2015. Taiwan also minimized the amount of waste disposal into landfills to less than 2%, while 80% of its industrial waste was recycled. About 33% of annual waste generation in Taiwan was reduced through "Pay-as-you-throw" policy. The average volume of municipal solid waste generation per capita decreased by 20% to 0.91 kg/day. This suggests that moving towards digitalization has minimized the extraction of raw materials through resource recovery. As implications of digitalization in waste management, the consumption of virgin materials could be lowered by 25% in 2030, while a half of greenhouse gas emissions could be avoided. The World Economic Forum estimated that the circular economy could potentially add USD 700 billion in material savings to global economy. [Display omitted] • Taiwan attained the second highest recycling target of 65% after Germany (67%). • Taiwan's 'Keep Trash off the Ground Policy' is transferable to St. Petersburg. • Pandemic hastens the transformation of recycling industry through digitalization. • Achieving carbon neutrality requires both economic and technological development. • Consumption of virgin materials could be lowered by 25% in 2030 by adopting CE. [ABSTRACT FROM AUTHOR]

This study provides the first evidence on the influence of the semiconductor and electronics industries on perfluorinated chemicals (PFCs) contamination in receiving rivers. We have quantified ten PFCs, including perfluoroalkyl sulfonates (PFASs: PFBS, PFHxS, PFOS) and perfluoroalkyl carboxylates (PFCAs: PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnA, PFDoA) in semiconductor, electronic, and optoelectronic industrial wastewaters and their receiving water bodies (Taiwan's Keya, Touchien, and Xiaoli rivers). PFOS was found to be the major constituent in semiconductor wastewaters (up to 0.13mg/L). However, different PFC distributions were found in electronics plant wastewaters; PFOA was the most significant PFC, contributing on average 72% to the effluent water samples, followed by PFOS (16%) and PFDA (9%). The distribution of PFCs in the receiving rivers was greatly impacted by industrial sources. PFOS, PFOA and PFDA were predominant and prevalent in all the river samples, with PFOS detected at the highest concentrations (up to 5.4μg/L). [Copyright &y& Elsevier]

Wastewater reuse can significantly reduce environmental pollution and save the water sources. The study selected Cheng-Ching Lake water treatment plant in southern Taiwan to discuss the feasibility of wastewater recycling and treatment efficiency of wastewater treatment units. The treatment units of this plant include wastewater basin, sedimentation basin, sludge thickener and sludge dewatering facility. In this study, the treatment efficiency of SS and turbidity were 48.35–99.68% and 24.15–99.36%, respectively, showing the significant removal efficiency of the wastewater process. However, the removal efficiencies of NH3–N, total organic carbon (TOC) and chemical oxygen demand (COD) are limited by wastewater treatment processes. Because NH3–N, TOC and COD of the mixing supernatant and raw water are regulated raw water quality standards, supernatant reuse is feasible and workable during wastewater processes at this plant. Overall, analytical results indicated that supernatant reuse is feasible. [ABSTRACT FROM AUTHOR]

Abstract: Taipei Municipal City (TMC) began implementing a policy of a plastic-bag-based disposal fee for household solid waste treatment in July 2000, while other counties kept their same charge of a disposal fee based on potable water consumption. Taiwan''s EPA has highly valued the outcome of TMC''s new policy and has thus required all counties to follow TMC in employing a policy of a plastic-bag-based disposal fee accompanied by a compulsory sorting system. We attempt to verify whether the new policy implemented by TMC is successful in the reduction of general waste collected and then we seek to identify what other factors contribute to such a successful result. This paper provides a general overview of household waste management practices employed in Taiwan and the changes of household waste collected over time through simple statistical analysis and management practices, including evaluating waste recovery and recycling initiatives. The authors employ statistical analysis to verify TMC''s new policy and to examine the factors that affect its success in addition to the policy changes through a test on the Environmental Kuznets Curve (EKC). We separate the data into three groups: TMC, non-TMC regions, and the pooled data (combination of TMC and non-TMC). The results show that: (1) the policy of a plastic-bag-based disposal fee is significantly effective in the reduction of general waste collected; and (2) the per capita household solid waste collected in both regions (TMC and non-TMC) is significantly related with household incomes in an EKC relationship. However, the test of EKC relationships on the pooled data is not significant. [Copyright &y& Elsevier]

Abstract: The Hsinchu Science-based Industrial Park (HSIP) is the hi-tech manufacturing hub of Taiwan. Wastewater from the HSIP contains numerous nano-sized silicate particles whose size distributions peak at 2 and 90nm. A 3–5mgl−1 as Al dose of polyaluminum chloride (PACl) was used in the field to coagulate these particles, but the removal efficiency was low. Laboratory scale tests indicated that although PACl coagulation removed 52% of the turbidity and 48% of the chemical oxygen demand (COD) from water, its effect on nano-particle removal was minimal. About 58% of the soluble COD was associated with colloidal Si particles. A light scattering test and transmission electron microscopy (TEM) demonstrated that the nano-particles agglomerated in approximately linear aggregates of sizes 100–300nm. Prolonged contact between residual PACl and the nano-particles generated large aggregates with sizes of up to 10μm and a fractal dimension of 2.24–2.63. The results presented herein should be of interest in the processing of “high-tech” wastewater that contains nanosized silica particles. [Copyright &y& Elsevier]

Abstract: A multiple regression analysis was used to develop two predictive models of lower heating value (LHV) for municipal solid waste (MSW), using 180 samples gathered from cities and counties in Taiwan during 2001–2002. These models are referred to as the original proposed model (OPM) and the simplified model (SM). The coefficients of multiple determinations for the OPM and SM were 0.983 and 0.975, respectively. To verify the feasibility of the models, a demonstration program based on sampling of MSW in Kaohsiung City was conducted. As a result, the OPM showed superior precision in terms of relative percentage deviation (RPD) and mean absolute percentage error (MAPE), when compared to the conventional models based on the proximate analysis, physical composition and ultimate analysis. The SM was derived by neglecting the three minor physical components used in the OPM. The resulting SM was less precise when compared to the OPM, but it was still acceptable, with a precision level better than the conventional models. It was concluded that the predictability of empirical models could be improved significantly through selection of the appropriate physical components and multiple regression analysis. [Copyright &y& Elsevier]

Incineration is a major treatment process for municipal solid waste in Taiwan. It is estimated that over 1.5Mt of incinerator ash are produced annually. This study proposes using thermal plasma technology to treat incinerator ash. Sintered glass–ceramics were produced using quenched vitrified slag with colouring agents added. The experimental results showed that the major crystalline phases developed in the sintered glass–ceramics were gehlenite and wollastonite, but many other secondary phases also appeared depending on the colouring agents added. The physical/mechanical properties, chemical resistance and toxicity characteristic leaching procedure of the coloured glass–ceramics were satisfactory. The glass–ceramic products obtained from incinerator ash treated with thermal plasma technology have great potential for building applications. [Copyright &y& Elsevier]

In order to conservatively utilize natural resources, Taiwan’s Environmental Protection Administration (EPA), in cooperation with the Ministry of Economic Affairs (MOEA), has mandated the regulatory system and promotion programs for industrial waste reuse and pollution prevention. The newly-designated 43 items for reuse were promulgated by the MOEA under the authorization of the Waste Disposal Act (WDA) in January 2002. Also, joint efforts at industrial waste minimization (IWM) have made noteworthy progress towards the promotion of reusing/reducing industrial waste since 1990. The IWM program not only provides technical assistance and financial incentives, but also enhances resource reuse and conservation through Industrial Waste Exchange Information Service Center. These measures have brought significant benefits by saving treatment/disposal costs and improving productivity. This paper presents the regulatory system and implementation promotion on industrial waste reuse and pollution prevention in Taiwan. [Copyright &y& Elsevier]

Industrial symbiosis (IS) has contributed significant environmental and economic benefits in many industrial parks or regions, with inter-firm trade of wastes or by-products for reuse. To facilitate IS in more regions, information systems and tools could help identify the opportunities for more companies to mimic the successful cases of by-product synergies. A review of existing IS information systems showed that most lack sufficient quality data, are not operational, or are not publicly accessible. In addition, studies on the development of IS information systems have only limited descriptions of the programming approaches used to create the tools for matching companies and illustrating complicated network by-product synergies based on IS data. Based on Taiwan's waste data, this work presents a well-established IS information system with three applications designed for target users, including the companies involved in IS, the facilitators seeking to grow IS in industrial parks or regions, and waste management authorities. This web-based system was based on massive amounts of detailed industrial by-product input and output datasets. In the by-products' records of more than one metric ton per year, there are 1833 patterns of different by-products reused by various industries. A comparison with other IS information systems and data repositories shows the advantage of using a government-owned industrial waste database with detailed waste classification in identifying massive by-product synergies. Novel data visualization technologies are employed to interactively generate diagrams or networks in response to the user selection of by-products or industries of interest. A demonstration of the query on the sugar manufacturers using sugar cane presents ten by-products and potentially 222 reuses by different industries. [Display omitted] • An information system of rich by-product synergies built with industrial waste data. • The publicly accessible web applications empower the search for IS opportunities. • A method to explore by-product synergies from structured datasets is presented. • The program renders three kinds of interactive data visualizations for target users. [ABSTRACT FROM AUTHOR]

Incineration is the most important technology for treating municipal solid waste (MSW) and industrial waste in Taiwan. Currently, there are 24 large-scale MSW incineration plants operated to generate about 1.2 million metric tons of residual ash (mostly bottom ash) based on approximately 6.5 million metric tons of waste incinerated yearly. To reduce the depletion of non-renewable resources under the circular economy principle, the recycling of MSW incineration bottom ash (IBA) as recycled aggregate in concrete and construction applications has been progressed in recent years around the world. According to the official database, the trend analysis of MSW generation and treatment, electricity power and IBA generation from the MSW incineration plants over the past decade (2010–2019) was performed in this work. It showed an increased power generation, growing from 0.485 kWh/kg in 2010 to 0.530 kWh/kg in 2019. In 2019, 2738 GWh of power was sold to Taipower (one of the state-owned companies in Taiwan) for electricity grid connection, gaining income of about NT$ 5,089,383,000 (≈US$ 172,520,000) at an average rate of 1.86 NT$/kWh (0.063 US$/kWh). On the other hand, the ratios of incineration bottom ash (IBA) generation to refuse incinerated indicated a decreasing trend due to the increased operation efficiencies of MSW incineration plants. Based on the revised regulations implemented on 18 May 2020, the regulatory measures for promoting IBA recycling in Taiwan were promulgated to valorize it for the production of recycled aggregate under rigorous requirements for prevent it from polluting the environment. [ABSTRACT FROM AUTHOR]

As the second-largest city in Taiwan, the Kaohsiung municipality has faced serious environmental loadings in recent decades. Among them, waste management is a key issue because of large amount of urban and industrial waste produced daily. In this regard, waste-to-energy (WTE) systems adopting the best available control technology for air pollution is a win-win approach because it also generates electricity to mitigate the dependence on imported fossil fuels and the greenhouse gas emissions incidentally. In this work, the updated status of municipal solid waste (MSW) and WTE plants in Kaohsiung were analyzed to get the crux based on the official database. Using the operational data on the WTE plants over recent years (2003–2018), the analysis of operational efficiencies for the four WTE plants in Kaohsiung was addressed in the paper. It showed that their operational efficiencies, ranging from 0.287 to 0.568 kW-h/kg, indicated an approximate "bathtub curve" pattern. In addition, analyzing the project for revamping the Gangshan WTE plant showed a significant progress in operational efficiencies with a significant increase from 0.506 kW-h/kg in 2016 to 0.587 kW-h/kg in 2018. Finally, some recommendations on technological measures and regulatory incentives for upgrading the operational efficiencies of existing WTE plants were addressed in the work. [ABSTRACT FROM AUTHOR]