Daily Question, June 30, 2016 (EIA Discussion): 3 Wealth points for replies, plus 5 Wealth points for correct answers (short answer question)

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This post was last edited by Zhang Xiaopeng on 2016-7-1 at 17:40. Starting today, I will analyze the actual exam questions from past years’ environmental impact assessment exams together with everyone; we won’t analyze those from 2016 for now (I’m not entirely sure myself: lol). I hope everyone will participate actively so that we can learn together! ! ! To make it easier for everyone to work on the questions, I will only list the key information related to the questions in the case studies. If you want to read the full content of the case studies, you can download past exam papers from the Internet. Content of Question 3 in 2013 regarding the cogeneration project: The local area suffers from a shortage of water resources, with groundwater being the main source of water supply for the city; large-scale groundwater depression zones have emerged in this region. To the northwest of the city, there is a reservoir with a capacity of 3.2×107 m3, whose main functions are flood control, supplying water to the city, and providing water for agriculture. The city’s existing secondary municipal wastewater treatment plant is located in the southern part of the urban area, with a treatment capacity of 1.0×105 tons per day. Once the wastewater has been treated to meet the required standards, it is reused in the industrial zone situated in the southwest of the city. It is planned to construct a cogeneration project in phases within the industrial zone in the southwest of the city. The first phase plans to construct a 350 MW cogeneration unit, accompanied by a coal-fired boiler with a capacity of 1160 t/h. The cooling of the turbine exhaust gas is planned to be carried out using a secondary circulation cooling method, with one naturally ventilated cooling tower. (The common methods for cooling turbine exhaust gas include direct water cooling, air cooling, and secondary circulation chilled water cooling.) The water used in production mainly includes water for chemical systems, water for circulating cooling systems, and water for desulfurization systems. The consumption of fresh water is 4.04×105 tons per year, 2.89×106 tons per year, and 2.90×105 tons per year respectively, and it is planned to draw water from reservoirs. Groundwater is used for domestic water supply. Title: Propose an optimization plan for water use in this project and explain the reasons. Answer: 1. The cooling method for the turbine exhaust steam is to be changed from secondary circulation cooling to air cooling. Reason: Northern cities suffer from water shortages, so the use of air cooling is encouraged, as it is a water-saving measure. 2. Production water should be replaced with reclaimed water from urban sewage treatment plants, with reservoirs in the northwest serving as a backup water source; groundwater extraction is prohibited. Reason: The amount of water available from urban sewage treatment plants is more than sufficient to meet the water needs for production in this project; 1.0×105*365 > 4.04×105 + 2.89×106 + 2.90×105. 3. Reused treated wastewater should be used as much as possible for production purposes. Reason: The wastewater generated by power plants is easy to treat, allowing for zero emissions. Answer explanation: The information provided in this question is lengthy and scattered. The key point here is the order of using water resources: reclaimed water > surface water > groundwater. According to the given information, the area suffers from a shortage of water resources, and groundwater is the main source of water supply for the city; moreover, large-scale groundwater depression zones have formed in this region. Therefore, it is prohibited to extract groundwater.