A study of inline chemical coagulation/precipitation-ceramic microfiltration and nanofiltration for reverse osmosis concentrate minimization and reuse in the textile industry

Reverse osmosis concentrate (ROC) is one of the major drawbacks in membrane treatment technologies specifically due to the scale-forming ions. It is important to remove these ions from ROC to enhance total water recovery and reuse in the textile industry that is the largest water-consumer and polluter industry. In this work, coagulation/high pH precipitation (CP) integrated with ceramic microfiltration (CMF) was studied as a pretreatment method followed by nanofiltration (NF) to increase the efficiency of water recovery. To prevent organic fouling, ferric chloride (FeCl3) was applied at a concentration of 3 mM, and ceramic membranes were used for the removal of non-precipitating crystals and/or suspended solids (at high pH) before the NF processes. The CP-CMF method successfully removed calcium (Ca2+), magnesium (Mg2+), silica (SiO2), and TOC up to 97, 83, 92, and 87% respectively, which resulted in higher performance of the NF process. Moreover, this method provided higher flux at lower pressure that ultimately increased overall water recovery of the NF process to achieve near-zero liquid discharge (n-ZLD). A cost-benefit estimation showed that a high-quality effluent (COD<5 mg/L; conductivity 700<μS/cm; negligible residual color) can be generated and recycled in the textile industry at an economical cost (approximately 0.97 USD/m3). Therefore, ROC minimization and water recovery can help to achieve n-ZLD using CP-CMF/NF method.

Evaluating Benefits of Eco-Agriculture: The Cases of Farms along Taiwan’s East Coast in Yilan and Hualien

The ecological agriculture (hereinafter referred to as eco-agriculture) concept has grown rapidly in Taiwan in recent years. More and more successful eco-agriculture projects have thus sprouted up in Taiwan, and so a quantitative evaluation model of such projects becomes critically important for improving public understanding of eco-agriculture and for providing a basis for policy analysis. This research thus proposes a quantitative evaluation model for eco-agriculture and analyzes the empirical data collected. We take four farms that practice eco-agriculture in eastern Taiwan for the estimation of direct benefits by surveying farmers about their revenues and costs of crop yields. To evaluate indirect benefits, we employ the Contingent Value Method (CVM) to investigate the willingness-to-pay (WTP) of users and non-users to support eco-agriculture. Results from the direct benefit estimation indicate that eco-agriculture adoption is unlikely to improve the local livelihoods of farming communities. In terms of indirect benefit estimation, eco-agriculture is beneficial to society, but based on our analysis of the direct benefits, these indirect benefits fail to be transformed into profits, showing that eco-agriculture exhibits positive externalities. This constitutes unavoidable challenges for eco-agriculture to be sustainable if these positive externalities cannot be internalized.

Costs and Benefits of Autonomous Shipping—A Literature Review

The development of autonomous ship technology is currently in focus worldwide and the literature on this topic is growing. However, an in-depth cost and benefit estimation of such endeavours is in its infancy. With this systematic literature review, we present the state-of-the-art system regarding costs and benefits of the operation of prospective autonomous merchant ships with an objective for identifying contemporary research activities concerning an estimation of operating, voyage, and capital costs in prospective, autonomous shipping and vessel platooning. Additionally, the paper outlines research gaps and the need for more detailed business models for operating autonomous ships. Results reveal that valid financial models of autonomous shipping are lacking and there is significant uncertainty affecting the cost estimates, rendering only a reliable evaluation of specific case studies. The findings of this paper may be found relevant not only by academia, but also organisations considering to undertake a challenge of implementing Maritime Autonomous Surface Ships in their operations.

Economic Valuation of Benefits in Freshwater Ecosystems: Complex Wetlands System Belonging to the San Juan River in the Magdalena Medio Region, Colombia

This paper identifies and assesses the economic value of the main natural benefits relating to the complex system of wetlands (CSW) belonging to the San Juan River in the Colombian Magdalena Medio. This is a region rich in biodiversity and natural resources, which in the past was hit by violence and the actions of different armed groups. Benefit estimation takes into account diverse monetary valuation techniques, such as market prices for direct wetland uses and the transfer of benefits, for the assessment of indirect use and non-use values. The results reveal that the most important values relate to ecotourism (60.1%) as a possible future use of the CSW, the benefit of preventing flooding (28.4%), and the biodiversity that inhabits the area (6.7%). All three values represent the total economic value of the CSW. This research also finds that the benefits of the ecosystems currently provided by the CSW exceed the opportunity cost, represented by the total conversion of the area to livestock. Lastly, the net present value (NPV) of 25 and 75 years, relating to the benefits of the CSW, exceeds the income from the conversion of land to livestock, revealing profitable investments in conservation and ecotourism projects.

Evaluating Special Events: Merging Two Essential Approaches

In special event evaluation, given the shift away from standard economic impact analysis based on input–output modeling, increased attention is being paid to the roles that computable general equilibrium modeling (CGE) and cost–benefit analysis (CBA) can play in event evaluation. This article analyzes the strengths and limitations of CGE and CBA in the context of event assessment. A "hybrid" approach is outlined which includes a role for the advantages of both techniques to be included in the evaluation process. The issues addressed are theoretically important for both impact and benefit estimation, while having significant practical implications for event assessment.