Ecological and economic assessment of the role of seaweeds in abalone integrated multi-trophic aquaculture - a South African case study.

Author(s):  
Ana M Nobre ◽  
Deborah Robertson-Andersson ◽  
Amir Neori ◽  
Kishan Sankar

Abstract South Africa (SA) is the world's third largest abalone producer. The industry is now challenged by restrictions on access to wild kelp, which is the natural food for abalone. Abalone farmers in SA have recently begun implementing integrated multi-trophic aquaculture (IMTA) with the seaweed Ulva lactuca L. and the abalone Haliotis midae L. The positive aspects include: (1) better abalone growth when fed with mixed algae diet, (2) farm effluent reduction, (3) avoidance of contaminated seawater during red tides/oil spills, (4) promoting employment in rural coastal communities. This case study presents a quantification exercise that compares the ecological-economic costs/benefits associated with the seaweed-culture integration into the abalone industry. Data from an abalone farm from the Western Cape with annual production of 240 metric tonnes (MT) was used. The ecological-economic performance of abalone production in monoculture using a water flow-thorough system was compared against two IMTA scenarios, with water recirculation through a seaweed culture unit that replaces part of the wild kelp consumption. The comparison of monoculture with IMTA scenarios indicates an overall economic gain of between 1.1-3.0 million US$ per year. This range of values reflects the effects of adopting IMTA on the farm's profit and the environmental gains, which represent 80% of the estimated overall benefits and includes: avoided kelp bed restoration, reduced nutrient discharge and avoided greenhouse gas emissions (due to energy savings). This analysis is particularly important in informing the SA industry and regulators about the value of the implementation by the abalone farmers of IMTA systems. For this particular case study the message is that the IMTA approach provides substantial economic incentives to the abalone farmers and even larger benefits to the public, compared with the abalone monoculture production.

2020 ◽  
Vol 12 (23) ◽  
pp. 10111
Author(s):  
Younness EL Fouih ◽  
Amine Allouhi ◽  
Jamil Abdelmajid ◽  
Tarik Kousksou ◽  
Youssef Mourad

Mosques are buildings with a unique occupancy schedule and special energy and water consumption scheme. Generally, this type of buildings lacks the application of energy efficiency solutions and sustainable guidelines during the conception, construction and the operation phase. Interestingly, these iconic edifices can play a key role in raising awareness for sustainability and promoting cleaner energy technologies. The first aim of this work is to present energy audit results, recommended energy savings solutions for two historical mosques in Marrakech (Morocco). A detailed discussion of the adopted solutions is presented and an economic assessment was performed. Then, a two-year energy savings evaluation was conducted for the two mosques. Conclusions about the adequacy of the proposed solutions is presented. The second part is dedicated to outline some guidelines and sustainable criteria to consider for establishing an international sustainable mosques label. The creation of a such sustainable label will encourage spreading sustainable best practices in mosques and other types of buildings. It will also help to compare sustainable performances of different mosques around the world by establishing an adapted sustainable rating system.


TAPPI Journal ◽  
2012 ◽  
Vol 11 (8) ◽  
pp. 17-24 ◽  
Author(s):  
HAKIM GHEZZAZ ◽  
LUC PELLETIER ◽  
PAUL R. STUART

The evaluation and process risk assessment of (a) lignin precipitation from black liquor, and (b) the near-neutral hemicellulose pre-extraction for recovery boiler debottlenecking in an existing pulp mill is presented in Part I of this paper, which was published in the July 2012 issue of TAPPI Journal. In Part II, the economic assessment of the two biorefinery process options is presented and interpreted. A mill process model was developed using WinGEMS software and used for calculating the mass and energy balances. Investment costs, operating costs, and profitability of the two biorefinery options have been calculated using standard cost estimation methods. The results show that the two biorefinery options are profitable for the case study mill and effective at process debottlenecking. The after-tax internal rate of return (IRR) of the lignin precipitation process option was estimated to be 95%, while that of the hemicellulose pre-extraction process option was 28%. Sensitivity analysis showed that the after tax-IRR of the lignin precipitation process remains higher than that of the hemicellulose pre-extraction process option, for all changes in the selected sensitivity parameters. If we consider the after-tax IRR, as well as capital cost, as selection criteria, the results show that for the case study mill, the lignin precipitation process is more promising than the near-neutral hemicellulose pre-extraction process. However, the comparison between the two biorefinery options should include long-term evaluation criteria. The potential of high value-added products that could be produced from lignin in the case of the lignin precipitation process, or from ethanol and acetic acid in the case of the hemicellulose pre-extraction process, should also be considered in the selection of the most promising process option.


1968 ◽  
Vol 8 (2) ◽  
pp. 308-309
Author(s):  
Mohammad Irshad Khan

It is alleged that the agricultural output in poor countries responds very little to movements in prices and costs because of subsistence-oriented produc¬tion and self-produced inputs. The work of Gupta and Majid is concerned with the empirical verification of the responsiveness of farmers to prices and marketing policies in a backward region. The authors' analysis of the respon¬siveness of farmers to economic incentives is based on two sets of data (concern¬ing sugarcane, cash crop, and paddy, subsistence crop) collected from the district of Deoria in Eastern U.P. (Utter Pradesh) a chronically foodgrain deficit region in northern India. In one set, they have aggregate time-series data at district level and, in the other, they have obtained data from a survey of five villages selected from 170 villages around Padrauna town in Deoria.


2017 ◽  
Vol 19 (5) ◽  
pp. 486-503 ◽  
Author(s):  
Brett R. Caraway

This article outlines a socio-political theory appropriate for the study of the ecological repercussions of contemporary media technologies. More specifically, this approach provides a means of assessing the material impacts of media technologies and the representations of capitalist ecological crises. This approach builds on the work of ecological economists, ecosocialist scholars, and Marx’s writings on the conditions of production to argue that capitalism necessarily results in ecological destabilization. Taking Apple’s 2016 Environmental Responsibility Report as a case study, the article uses the theory to analyze Apple’s responses to ecological crises. The article asserts that Apple’s reactions are emblematic of the capitalist compulsion for increasing rates of productivity. However, unless the matter/energy savings achieved through higher rates of productivity surpass the overall increase in the flow of matter/energy in production, ecological crises will continue. Ultimately, capital accumulation ensures continued ecological destabilization.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1172
Author(s):  
Hafiz Haq ◽  
Petri Välisuo ◽  
Seppo Niemi

Industrial symbiosis networks conventionally provide economic and environmental benefits to participating industries. However, most studies have failed to quantify waste management solutions and identify network connections in addition to methodological variation of assessments. This study provides a comprehensive model to conduct sustainable study of industrial symbiosis, which includes identification of network connections, life cycle assessment of materials, economic assessment, and environmental performance using standard guidelines from the literature. Additionally, a case study of industrial symbiosis network from Sodankylä region of Finland is implemented. Results projected an estimated life cycle cost of €115.20 million. The symbiotic environment would save €6.42 million in waste management cost to the business participants in addition to the projected environmental impact of 0.95 million tonne of CO2, 339.80 tonne of CH4, and 18.20 tonne of N2O. The potential of further cost saving with presented optimal assessment in the current architecture is forecast at €0.63 million every year.


Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 156
Author(s):  
Paige Wenbin Tien ◽  
Shuangyu Wei ◽  
John Calautit

Because of extensive variations in occupancy patterns around office space environments and their use of electrical equipment, accurate occupants’ behaviour detection is valuable for reducing the building energy demand and carbon emissions. Using the collected occupancy information, building energy management system can automatically adjust the operation of heating, ventilation and air-conditioning (HVAC) systems to meet the actual demands in different conditioned spaces in real-time. Existing and commonly used ‘fixed’ schedules for HVAC systems are not sufficient and cannot adjust based on the dynamic changes in building environments. This study proposes a vision-based occupancy and equipment usage detection method based on deep learning for demand-driven control systems. A model based on region-based convolutional neural network (R-CNN) was developed, trained and deployed to a camera for real-time detection of occupancy activities and equipment usage. Experiments tests within a case study office room suggested an overall accuracy of 97.32% and 80.80%. In order to predict the energy savings that can be attained using the proposed approach, the case study building was simulated. The simulation results revealed that the heat gains could be over or under predicted when using static or fixed profiles. Based on the set conditions, the equipment and occupancy gains were 65.75% and 32.74% lower when using the deep learning approach. Overall, the study showed the capabilities of the proposed approach in detecting and recognising multiple occupants’ activities and equipment usage and providing an alternative to estimate the internal heat emissions.


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