Search

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]

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 paper presents an empirical study of how three waste management policies have affected residential waste generation and recycling behavior in Taiwan over the past decade. The three policies are unit-pricing of garbage in Taipei, a mandatory recycling program in Kaohsiung, and a nationwide policy of charging for plastic bags. We estimate policy effects on total waste, total recycling, and recycling of four specific materials, all measured by weight per capita. Unlike prior work, we find that unit-pricing and mandatory recycling policies lead to significant increases in recycling of most materials, as well as increased levels of total recycling and garbage reduction. The “plastic bag” policy is generally found to lower material-specific and total recycling rates, as well as total garbage volumes. [ABSTRACT FROM AUTHOR]

This study examined the reuse potential of the effluents discharged from several unified wastewater treatment plants (WWTPs) of industrial parks in Taiwan, with designed capacity exceeding 10,000 CMD. Parameters were selected based on the relevant reuse purposes. The "potential recycling percentage", R of the WWTP effluent was defined as the maximal percentage of pure water extractable by the "ideal reverse osmosis module" while the RO retentate still met local effluent standards and required no treatment. The analytical results demonstrated that the WWTP effluents had potential for recycling. A pilot plant was installed in one of the WWTPs. The treatment process included a sand filter, an ultrafiltration unit (UF) and a reverse osmosis module (RO). Results of this study demonstrated that the production quantity and quality are stable and appropriate for various purposes, including both industrial and domestic applications. [ABSTRACT FROM AUTHOR]

Two MBR pilot systems were constructed and tested in the Bali Primary WVVTP. The pilot study shows that two MBR systems, i.e. the Green-MenBio system (MBR-1) and the Bio-MF system (MBR-2), can both fulfill the requirement of wastewater reclamation standard, The MBR-2 system is more economical compared with MBR-1 system. The cost of US$ 0.10–0.16/m³ is estimated to reclaim the effluent of primary WWTP in Taiwan. The Bali Primary VVWTP has the capacity of 1,320,000 cmd which is the biggest in Taiwan. The domestic wastewater of partial Taipei City and Taipei County are collected and transported to the Bali Primary WWTP. The effluent of the Bali Primary WVVTP is then discharged into the ocean through two 3.8 m marine outfalls. The AO processes are installed in both MBR systems. More than 90% of the NH3-N can be removed through the AO and membrane processes. The outflow of the MBR systems (without RO) can reach the quality of COD < 30 mg/l, BOD < 10 mg/l, SS < 5 mg/l, NH3-N < 3 mg/L. The outflow of the MBR system is proposed to transport 40 km south to the Taoyuan County where four new industrial parks are to be constructed. Part of the reclaimed water is to be used on irrigation and another portion is to be sent to the industries after RO treatment. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this paper is to present a compilation of recent Taiwan government laws/regulations to promote industrial waste recycling. The description is thus centered on legislation/regulations concerning general industrial wastes recycling in the policies of environmental protection, economic incentives and engineering technologies (3E) that have become effective since 2001. The regulatory system, including Waste Disposal Act, Resource Recycling/Reuse Act, Environmental Basis Law, and Statute for Upgrading Industries, not only gives financial incentives, but also provides technical assistance and information transfer on promoting industrial waste recycling. In order to further utilize the recyclable resources and upgrade the environmental technology, Taiwan’s Environmental Protection Administration (EPA), in cooperation with the Ministry of Economic Affairs (MOEA), has jointly ventured some promotion programs, which highlight an Industrial Waste Exchange Information Center and Environmental Technology Park Development Program, also described in the paper. [Copyright &y& Elsevier]

The article discusses the use of online recycling of calcium fluoride (CaF2) sludge as a method of developing a green process in a C9 resin manufacturing plant in Taiwan. Ordinary CaF2 sludge, which contains reacted and unreacted monomers, was activated with fresh lime for recycling and termination use. Results show that an unusual odor was emitted from the CaF2 sludge activated with 10% fresh lime, but adding 20% fresh lime for activation solved the problem. It was concluded that this method can reduce the treatment cost and CaF2 sludge generation by 40%.