Document Actions
Impact on Water Quality
Up one level
5.2. Impact on Water Quality
The impact of the effluent from Smolensk from the MWTP, all other treatment plants, other discharges including stormwater has a significant but not decisive impact on the water quality in the Dnieper River. Data concerning water quality in the Dnieper River upstream and downstream main sewerage waste treatment facilities prior the discharge and after the discharge of wastewater are given in Table 5.2, below.
Table 5.2 : Water quality in the Dnieper River upstream and downstream of main wastewater treatment facilities in 2001
|
Pollutants |
Prior to discharge (mg/l) |
After discharge, mg/l |
|
BODtotal |
20 |
20 |
|
BOD5 |
5,6 |
6,2 |
|
Suspended solids |
6,7 |
7,0 |
|
Ammonia |
0,32 |
0,33 |
|
Nitrites |
0,036 |
0,033 |
|
Nitrates |
0,31 |
0,31 |
|
Total nitrogen |
0,95 |
0,96 |
|
Phosphates |
0,07 |
0,08 |
|
General phosphorous |
0,1 |
0,11 |
|
Chromium |
0,016 |
0,008 |
In 2001 the BOD load made up 12,410 ton/year. The share of industry comes to 6,205 ton/year.
In 2001 total nitrogen load was stable, approximately at the level of 2000. The share of industry makes up 692 ton/year.
Total phosphorus load made up 292 ton/year. The share of industry came to 36 ton/year.
Concentration of heavy metals in wastewater coming for treatment is low. Usually storm water from urban territories is the reason of high concentration of zinc and copper, whereas high chromium content is accounted for industrial sources. This indicates that industry can have strong impact on the quality of wastewater. Adverse impacts of industrial effluents on main sewerage waste treatment facilities are significant as many industries do not comply with their discharge limits and spills and upsets occur periodically.
At the same time normatives of discharge are strict and current methods of treatment do not always ensure standards compliance.
There are also strict normatives of discharge of the salts of heavy metals. Biological process used at the main sewerage waste treatment facilities cannot eliminate the content of salts of heavy metals or at least reduce it up to normative level. In order to meet these standards it is necessary to take the necessary steps toward the suppliers of wastewater. Table 5.3 presents average peak data at the point of entry of Smolensk municipal waste treatment facilities.
Table 5.3 : Pollutants at the entry of municipal waste treatment facilities of Smolensk
|
Parameters |
BOD5, mg/l |
Suspended solids, mg/l |
|
Design data Actual data in 2001 |
125 247 |
247 419 |
Technical Issues
The lack of automatic monitoring of control parameters constrains treatment performance. For example, the absence of monitoring devices for dissolved oxygen in the aeration tanks results in significant variance from optimum DO levels. This can result in excessive energy usage and associated expenses in this example or in other areas, inadequate treatment
fi0The processes are not automated and adjustments are made manual under the direction of the Chief Engineer based on the results of sample analysis conducted by the on-site laboratory. Flow measurement and control is limited so such adjustments are restricted.
