关键词：应用系统分析，城市区域，食物，营养，系统动力学，水
摘 要：非洲城市地区的一些最重要挑战与食物、能源、水和营养有关。为了应对这些挑战，出现了一些观点，认为城市应该再生、节约资源并阻止生态系统的衰退。因此，通过考虑奇维罗湖和哈拉雷市区域之间的联系进行了一项案例研究，以概念化水-营养-食物关系的框架，并研究处理到奇维罗湖的废水中的营养物质如何有助于促进哈拉雷市区域的食物生产。采用应用系统分析（ASA）关联系统动力学（SD）建模方法。据观察，城市区域的供水、奇维罗湖的废水产生和处理、营养物质、食品生产、食品消费和城市消费产生的废水都在反馈机制中工作。在反馈机制的前提下，ASA关联SD模型估计奇维罗湖的沉积物中已经积累了约19800吨氮（N），其中一半以上可以提取。为了理解其重要性，据估计，如果在城市地区提取和利用 100 吨氮，可能有助于生产超过 35,000 吨的食物。因此，城市区域产生的垃圾需要作为一种资源进行回收利用，这可能会将顽固的污染问题转化为资源回收以及城市区域环境和社会经济福祉的收益。
Abstract:Some of the most important challenges in the city regions of Africa are related to food, energy, water, and nutrients. To meet these challenges, arguments have emerged that cities should become regenerative, resource-efficient and arrest the decline of ecosystems. Therefore, a case study was performed by considering the linkage between Lake Chivero, and the Harare city region to conceptualize a framework of the water-nutrient-food nexus and to examine how nutrients from the wastewater that is disposed to Lake Chivero can assist in contributing to the food production in the Harare city region. An Applied Systems Analysis (ASA) linked System Dynamics (SD) modelling methodology was used. It is observed that the water supply in the city region, wastewater generation and disposal to Lake Chivero, nutrients, food production, food consumption and wastewater generated from consumption in the city, all work in a feedback mechanism. Premised upon the feedback mechanism, the ASA linked SD model estimates that Lake Chivero has already accumulated about 19,800 tonnes of Nitrogen (N) in its sediments, of which over half can be extracted. To comprehend the significance, it is estimated that 100 tonnes of N might assist in the production of over 35,000 tonnes of food if extracted and utilised in the city region. Therefore, the waste generated in the city region needs to be considered as a resource and recovered, which might turn a recalcitrant problem of pollution into the benefits of resource recovery and environmental and socio-economic wellbeing of the city region.
Key:Applied Systems Analysis, City region, Food, Nutrients, System Dynamics, Water
全文: DOI