Information on the Environment in the CR (1999-2004)
A-2. Water | Contents |
Table A - 2.1, A - 2.10, A - 2.11
Selected pollutants
- biological oxygen demand (BOD5): the amount of oxygen consumed for aerobic biochemical decomposition of organics, contained in water for five days under standard conditions
- chemical oxygen demand (CODCr): the amount of oxygen (O2) as determined by the dichromate method
- insolubles (NL): substances determined by filtering water and drying up the residue at 105 °C to constant weight
Determination of water quality in streams
The profile refers to a place where measurements are carried out.
Pollution degree classification:
I - very clean water
II - clean water
III - polluted water
IV - heavily polluted water
V - very heavily polluted water
Indicator (v mg/l) | Class | ||||
I. | II. | III. | IV. | V. | |
| BOD5 | <2 | <5 | <10 | <15 | >15 |
| CODCr | <15 | <25 | <35 | <55 | >55 |
| N-NO3 | <1,0 | <3,4 | <7,0 | <11,0 | >11,0 |
| N-NH4 | <0,3 | <0,5 | <1,5 | <5,0 | >5,0 |
| TP (total phosphorus) | <0,03 | <0,15 | <0,4 | <1,0 | >1,0 |
Classification according to CSN 75 7221.
Table A - 2.2 to A - 2.9 Public water supply and sewerage systems
Methodology of processing of the Questionnaire VH 8b-01 (on water supply and waste water treatment) was changed since 2004. A total of 207 operators of water supply and sewerage systems submitted the questionnaire for the year 2004. To these operators a sample of municipalities was attached, that operate public supply and sewerage systems on their own. Taken all in all, the number of respondents was enlarged to 1 510 reporting units. Due to the significant increase in the number of reporting units on the previous year, a new model of the mathematical statistical grossing-up procedure was developed so that all monitored indicators on water supply and sewerage systems could be obtained.
Thus break in time series can be found for some indicators.