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Black smelly body of water

Black smelly water monitoring solution

1 Overview

The black and stinky waters in cities not only bring extremely poor sensory experience to the people, but also directly affect the lives of the people, which is a prominent environmental problem. As of 2017, a total of 2082 black and odorous water bodies have been identified nationwide, and 1,310 have not been completely treated. Although some cities have achieved significant results, the overall governance situation is still not optimistic. Compared with the number of black odorous water bodies identified in the first quarter (1861) and the fourth quarter (1915) of 2016, the number of black odorous water bodies is gradually increasing, which also reflects the complexity of managing black odorous water bodies and maintaining the black odor The difficulty of the body of water. A timely and effective black smelly water body monitoring platform can not only provide real-time water quality conditions, but also help the management team to take measures to maintain good water quality before water quality deteriorates, saving manpower and resources, saving time and efficiency, which is indispensable for black smelly water body treatment. portion.

Major cities with black and stinky water bodies in China in 2017

2. Evaluation indicators

According to the degree of black odor, black odorous water can be subdivided into two levels: "mild black odor" and "severe black odor". The main evaluation indicators include transparency, dissolved oxygen (DO), redox potential (ORP), and Ammonia nitrogen (NH3-N), specific standards and related indicators are determined in Tables 2 and 3 below:

Table 2 Classification standards for pollution degree of urban black and odorous water

Characteristic index (unit) Mildly black Severe black
Transparency (cm) 25 ~ 10 * < 10 *
Dissolved oxygen (mg / L) 2.0 0.2 ~ 2.0 <0.2
Redox potential (mV) -200 ~ 50 <-200
Ammonia nitrogen (mg / L) 15 8.0 ~ 15 > 15

Note: * When the water depth is less than 25cm, the index is taken as 40% of the water depth.

Table 3 Water quality index measurement methods

Serial number project test methods Remark
1 transparency Black-and-white disk or typeface In-situ measurement
2 Dissolved oxygen Electrochemical method In-situ measurement
3 Redox potential Electrode method In-situ measurement
4 Ammonia nitrogen Nessler's reagent spectrophotometry or salicylic acid-hypochlorite spectrophotometry Water sample filtered through 0.45μm filter

Note: For related index analysis methods, please refer to "Water and Wastewater Monitoring and Analysis Methods (Fourth Edition) (Supplementary Edition)"

3. Monitoring System

a. system design

Black smelly water monitoring system

  • TSS immersion turbidity / suspension concentration meter

  • LDO fluorescence dissolved oxygen meter

  • pH / ORP meter

  • DNH electrode method ammonia nitrogen analyzer