What Is A Black Water Body?

Black-odor water body is a collective term for water bodies that exhibit unpleasant colors and/or emit unpleasant odors. Generally, the evaluation indicators for black-odor water bodies mainly include four items: transparency, dissolved oxygen (DO), oxidation reduction potential (ORP) and ammonia nitrogen (NH3-N).

The grading standards  and the related index measurement methods

Grading standards for the degree of pollution of black-odor water bodies Characteristic indicators (unit) Light black-odor Heavy black-odor Transparency (cm) 25~10*<10*,

Dissolved oxygen (mg/L) 0.2~2.0<0.2

ORP Oxidation reduction potential (ORP) (mV) -200~50< -200

Ammonia nitrogen (mg/L) 8.0~15>15

Note:*

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

Determination method of water quality indicators

1. Transparency black and white disk method or lead method on-site in-situ determination

2. Dissolved oxygen electrochemical method on-site in-situ determination

3. Redox potential electrode method on-site in-situ determination

4. Ammonia nitrogen Nano reagent photometry or salicylic acid - hypochlorite photometry Water samples should be filtered through a 0.45 μm filter membrane