《深入打好城市黑臭水体治理攻坚战实施方案》的发布，让不少目光聚焦到了更为细致的地方，如：“建立健全垃圾收集(打捞)转运体系”，“不应盲目提高污水处理厂出水标准、新扩建污水处理... 《深入打好城市黑臭水体治理攻坚战实施方案》的发布，让不少目光聚焦到了更为细致的地方，如：“建立健全垃圾收集(打捞)转运体系”，“不应盲目提高污水处理厂出水标准、新扩建污水处理厂”，“到 2025 年，进水BOD 浓度高于 100 毫克/升的城市生活污水处理厂规模占比达90%以上”，“严格做好‘农家乐’、种植采摘园等范围内的生活及农产品产生pollution及garbage治理”，“black water body整治not in place问题纳入中央生态环境保护督察和长江经济带、黄河流域生态环境警示片现场调查拍摄范畴”，“落实water pollution treatment fee policy”, “推广以water pollution treatment plant input pollution substance concentration, pollutant reduction quantity and sludge handling disposal quantity as payment for operation and maintenance services”等。本文就这个问题来探讨一下。1. What is BOD? BOD, biochemical oxygen demand, refers to the amount of dissolved oxygen consumed by microorganisms during the biological chemical reaction process of degrading organic matter in water. It is a comprehensive index reflecting the content of organic pollutants in water and an important parameter for evaluating water quality. Generally, the five-day biochemical oxygen demand (BOD5) should not exceed 2mg/L for clean rivers; industrial, agricultural, and aquaculture wastewater should not exceed 5mg/L; while drinking water should be less than 1mg/L. According to the "Urban Wastewater Treatment Plant Pollutant Emission Standards" (GB18918-2002), modified version (draft for comments), BOD5's maximum allowable emission concentration is: level I A:15 mg/L；level I B:30 mg/L；level II:45 mg/L；and level III:70 mg/L.
Why can't progress be made if the influent BOD is low? From these definitions it seems that a high value indicates more organic pollutants are present. However, this confusion lies in whether or not sewage separation has been carried out properly.
The above plan clearly states that cities with influent biochemical oxygen demand (BOD) concentrations below 100 milligrams per liter must conduct pipe network inspections and improvements; clarify responsibilities for waste collection; implement regulations on industrial waste discharge into sewers; clear up rainwater drainage systems; trace sources of illegal discharges; carry out law enforcement campaigns against polluters etc.
Rainfall infiltration system improvement can be seen from here as well as pipeline expansion work.
Experts generally believe that most cases where influent BOD levels are too low can be traced back to non-domestic sewage entering sewer systems without proper dilution or slow flow rates within pipes resulting in sedimentation of suspended solids.
In other words, what they really care about when focusing on influent BOD levels is how effectively rainwater and sewage have been separated within urban drainage networks.
This highlights issues such as inadequate construction standards or aging infrastructure problems.
Another issue mentioned was that there was a lack of understanding regarding price mechanisms associated with upgrading existing pipelines.
As regards long-term development prospects however - The Chinese government plans massive investments into urban infrastructure projects over coming years including $140 billion worth new pipeline construction aimed at improving urban flood control measures across China’s major rivers like Yellow River & Yangtze River.
China's cities face significant challenges due to their rapid growth which has put pressure on their aging sewer systems
These issues require urgent attention because untreated sewage poses serious health risks
Note also that 'Seventeen Five' period will see widespread efforts towards building sponge cities - This includes making sure all city wastewater treatment plants have an influent BDO level greater than 100 milligrams per liter by end year.
This could mean additional investment opportunities arise from expanding urban drainage networks
If you're looking at making money off these trends then watch out!
标签： 地理资讯
