|
FIRST RELEASE |
CROATIAN
BUREAU OF STATISTICS ISSN 1334-0565 |
|||
|
|
||||
|
YEAR: XLVI. |
ZAGREB, 17 JUNE, 2009 |
NUMBER: 6.1.6. |
||
|
|
||||
|
|
OBLIGED TO NOTIFY DATA SOURCE |
|||
In 2008, the total volume of waste waters amounted to 322 718 000 m3.
Out of the total volume of waste waters, 229 206 000 m3 were from households and economic activities (increase of 8%), while 93 512 000 m3 were other waste waters (from precipitations etc.).
The volume of waste waters discharged from households decreased by 3%, while that discharged from economic activities increased by 27%
In 2008, there were 192 033 000 m3 of treated waste waters, which made 60% out of the total volume of waste waters. A positive trend of increasing the quality of treating continued in 2008 as well, which was expressed in the increase of the share of secondary treatment (by 68%) and of tertiary treatment (by 71%).
The structure of discharged waste waters showed that most waste waters were discharged into watercourses (69% of untreated and 81% of treated waste waters) and into the sea (29% of untreated and 19% of treated wasted waters).
In 2008, the sewage network was 7 674 km long, which was by 6% more than in the previous year. This increase was shown at the construction of a new general as well as a new separation system.
As compared to the previous year, the number of sewage connections increased by 3% and amounted to 413 792. The total number of waste water treatment plants was 109, which presented an increase of 1%. In the structure of treatment of waste water, the greatest increase was recorded in the number of the secondary treatment plants (77%), which contributed the most to the mentioned increase of treatment quality.
1. SOURCE, TREATMENT AND DISCHARGE OF WASTE WATERS ‘000 m3
|
|
2007. |
2008. |
Indices |
|
|
|
|
|
Waste waters – total |
211 346 |
322 718 |
153 |
|
|
|
|
|
|
From households |
131 939 |
128 403 |
97 |
|
From economic activities |
79 407 |
100 803 |
127 |
|
Other waters |
- |
93 512 |
- |
|
|
|
|
|
|
Treated waste waters –total |
140 228 |
192 033 |
137 |
|
Primary treatment |
57 565 |
52 792 |
92 |
|
Secondary treatment |
81 013 |
136 414 |
168 |
|
Tertiary treatment |
1 650 |
2 827 |
171 |
|
|
|
|
|
|
Discharged waste waters – total |
|
|
|
|
Untreated waters – total |
71 118 |
130 685 |
184 |
|
Discharged |
|
|
|
|
Into ground waters |
2 377 |
2 448 |
103 |
|
Into watercourses |
45 526 |
90 550 |
199 |
|
Into reservoirs |
- |
- |
- |
|
Into lakes |
- |
- |
- |
|
Into the sea |
23 215 |
37 687 |
162 |
|
Treated waters – total |
140 228 |
192 033 |
137 |
|
Discharged |
|
|
|
|
Into ground waters |
289 |
573 |
198 |
|
Into watercourses |
89 722 |
155 404 |
173 |
|
Into reservoirs |
- |
15 |
- |
|
Into lakes |
- |
- |
- |
|
Into the sea |
50 217 |
36 041 |
72 |
|
|
2007. |
2008. |
Indices |
|
|
|
|
|
|
Sewage network |
|
|
|
|
|
|
|
|
|
Number of pumping plants |
496 |
596 |
120 |
|
Total length of sewage network, km |
7 229 |
7 674 |
106 |
|
Of that, by type: |
|
|
|
|
General system, km |
5 394 |
5 640 |
104 |
|
Separation system, km |
1 835 |
2 025 |
110 |
|
Of that: |
|
|
|
|
Faecal, km |
1 532 |
1 718 |
112 |
Atmospheric, km |
303 |
317 |
104 |
|
|
|
|
|
|
The length of the main sewer, km |
1 374 |
1 428 |
104 |
|
Number of sewage connections |
400 994 |
413 792 |
103 |
|
Number of drains |
168 496 |
171 382 |
102 |
|
|
|
|
|
Waste water treatment plants |
108 |
109 |
101 |
|
|
|
|
|
|
Number of primary treatment plants |
75 |
62 |
83 |
|
Number of secondary treatment plants |
26 |
46 |
177 |
|
Number of tertiary treatment plants |
7 |
1 |
14 |
NOTES ON METHODOLOGY
Source and methods of data collection
Data on public sewage system are collected through regular annual reports on the VOD-2K forms − the Annual Survey on Public Sewage System.
Reporting units are legal entities and parts thereof, engaged, according to the Waters Act (NN, No. 107/95), in draining of waste waters from settlements (sub-group code 90 010 of the NKD 2002.) as well as communities and other organisations engaged in management of sewage system.
Coverage and comparability
Statistical surveys are based on the full coverage and the source for the address list is the Register of Business Entities. The survey provides basic information on waste waters, their treatment and discharging as well as on the sewage network and waste water treatment plants. The VOD-2K Survey is based on the Annual Implementation Plan of Statistical Activities in the Republic of Croatia for 2008 (NN, No. 65/08). Data are collected through the annual survey and the number of reporting units is 115.
Some data are not comparable due to the fact that the content of the VOD-2K form has been changed.
Definitions
Waste waters are waters that are considered waste ones after use. They are drained to the treatment plants after use, or discharged into the environment (into ground or surface waters). They include atmospheric waters as well.
Treated waste water comprises all amounts of waste water that were treated by using either primary (mechanical), secondary (biological) or tertiary (combined) treatment method.
The primary treatment includes the application of physical and/or chemical processes by which at least 50% of suspended solids are removed from the waste water, while the BOD5 value decreases as much as 20%, as compared to its value in the influent waters.
The secondary treatment includes the application of biological and/or other treatment processes by which the concentration of suspended solids and BOD5 decreases by even 70% to 90% and the concentration of COD by at least 75%.
The third treatment includes the application of physical and chemical, biological and other treatment processes by which the concentration of nutritious matters in influent waste waters decreases by as much as 80%, which means that other pollutants, which could not be removed to that extent in the secondary treatment, are now removed as well.
Public sewage system is a network of enclosed public drains and sewers used either for draining of both waste and atmospheric waters together (general water sewage system), or for separate draining of waste and atmospheric waters (separation water sewage system). The length of sewage system does not include the length of connections and networks within buildings.
Main sewer is a collecting drain that drains water from one part or the whole city to the recipient or to the treatment plant.
Abbreviations
BOD5 biochemical oxygen demand
COD chemical oxygen demand
km kilometre
m3 cubic metre
NKD 2002. National Classification of Activities, 2002 version
NN Narodne
novine, official gazette of the Republic
of Croatia
'000 thousand
Symbols
- no occurrence