Project 3. Hot Spot – State Unitary Enterprise “Inter-district Engineering Services, City of Novozybkov”

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10.4. Project 3. Hot Spot – State Unitary Enterprise “Inter-district Engineering Services, City of Novozybkov”

10.4.1. Description of Facility

Description of Municipal Treatment Facilities

Municipal sewerage system is in operation from 1976, it includes: drainage systems, discharge manifold, main sewerage pumping station, 6 sewerage pumping stations, drainage systems of meat-packing plant, sewerage wastewater treatment facilities, system of use of treated wastewater for technical water supply.

Population of the town of Novozybkov is 43.5 thousand people. 21.5 thousand people use centralized sewerage system. 22 thousand inhabitants use local sewerage system.

Municipal wastewater treatment facilities serve industrial, communal enterprises, budget organizations.  On the whole there are 18204 subscribers, including 133 enterprises and 18071 inhabitants.

In 2001 industrial effluents made up 547.5 thousand m³.  Wastewater discharge is registered by enterprises themselves.  Effleunt discharge from communal, budget enterprises and organizations made up 730 thousand m³, storm water came to 456.3 m³/year.  The volume of water used by population is 1916.5 thousand m³/year.  Total volume of effluent discharged to wastewater treatment facilities is 3659 thousand m³/year.

Wastewater coming to wastewater treatment facilities are composed of communal and industrial discharges.  According to the level of pollution they are qualified as the average concentration discharge and are characterised by the following major physical-chemical indicators of pollution (see Table 10.9).

It is expected that in the next 5-10 years the volume of effleunt  discharge will grow along with the content of hazardous substances; emergence of galvanization products.

 

Table 10.9 : Characteristics of Wastewater Received by Wastewater Treatment Facilities, mg/dm³

Wastewater treatment facilities ensure mechanical and biological treatment of wastewater.

Qualitative characteristics of wastewater treatment efficiency are given in Table 10.10.

Table 10.10 : Quality of Water in the Karna River, mg/l

 

Municipal sewerage system (58 km), discharge manifold (6 km), main sewerage pumping station and six pumping stations, providing treatment for 99% of the whole volume of wastewater, have been in operation since 1976.  Despite the efforts of the maintenance staff, equipment often stops working due to its old age.  Main sewerage pumping station and pumping stations require major repairs.

The average age of drainage systems is 25 years, including 26 km section over 25 years and 32 km section over 20 years.

Description of wastewater treatment facilities

At present municipal wastewater is discharged to the facilities of biological purification of the capacity of 3650 thousand m³/year.

The treatment facilities comprise of the following:

- Inlet chamber; reinforced concrete, dimensions 2.0 * 1.3 * 2.5.

Wastewater is supplied through three discharge manifolds.

- Screen facilities.  The screen facilities are equipped with two mechanized screen facilities of MG-7T type.

- Horizontal grit chambers.  The unit comprises of two grit chambers with circular motion of water of horizontal type.  De-sanding is performed by hydraulic elevator.  The sand is removed through the pipe to sand grounds.

- Sand grounds.  The complex is equipped with two sand grounds on the natural foundation from drainage with dimensions 35 * 80 m.

- Pumping station of sand grounds.  The pumping station of the treatment facilities is intended for pumping of drainage waters from sand grounds through drainage manifold to the central line before the grit chambers.

The engine-room is equipped with two pumps, one is running, the other is on stand by.

- Vertical primary clarifiers.  The complex of treatment facilities is equipped with four settling tanks d = 9 m.  The total volume of one settling tank is 334 m³.

Sludge removal is performed through the sludge pipe by hydrostatic pressure.  The settling tanks are intended for retention of coarsely dispersed insoluble.  The settling time is 1.5 hours.

- Aaeration tanks.  The complex of treatment facilities is equipped with two sections of aaeration tanks, with the corridor width of 6 m, depth of 4.4 m, length of 54 m, useful capacity of one section being 5700 m³.  The aaeration tanks are intended for complete biological treatment.  Water is supplied to the sections through the rectangular inlet covered with the panel.

The circulating activated sludge is supplied to the beginning of the first corridor of each section through the pipe turning into the chute.  The sludge mixture from the section overflows through the spillway and comes through the siphon to the canal of secondary settlers.  The air in canals is distributed by tube pneumatic aaeration tanks.

- Final sewage settling tanks.  The treatment facilities are equipped with eight settling tanks.  The settling tanks provide for settling of the activated sludge supplied to the aaeration tank.  The volume of a settling tank is 226 m³, with the total height of 6.85 m.  The sludge is removed under hydrostatic pressure to the circulating sludge reservoir with V = 100 m³, then pumped back to the aaeration tanks, and partially to concentration tanks.

- Concentration tanks.  There are two concentration tanks d = 9 m, h = 7.3 m for sedimentation of the excess activated sludge.  The clarified water is supplied through the spout to the chute, and then to the pumping station of the sludge grounds.  The concentrated sludge is removed through the sludge pipe into the concentrated sludge reservoir, and then is pumped to the sludge grounds.

- Sludge drying beds.  These are constructed on the natural foundation with drainage wells and intended for reception of excess sludge and wet sediment.  There are six drying beds.  The size of drying beds is 100 * 40 m.  The drainage water is supplied to the pumping station of the sludge drying beds.

The pumping station of the sludge drying beds is intended for pumping of the drainage water from the sludge drying beds and local sewer system to the inlet of the treatment facilities.  The pumping is performed by two pumps (one is running, the other is on stand by).

- Blower installation.  The blower installation has three blowers for air supply to the aaeration tanks, two pumps for technical water, two pumps for concentrated excess sludge, two pumps for pumping circulating activated sludge.

Due to the long term of operation, some installations are worn-out.

The majority of the town population is not connected to the central sewage system.  Complete canalizing of the city rayons, not connected to the sewage system, creation of environmentally sound operation conditions and reduction in faecal discharge into water bodies and on the ground surface require construction of 120 km of sewage system, 22 km of discharge manifolds, eight pumping stations.

There are 18 operating drinking water supplies wells in the town.  Drinking water is used for technical purposes.

The enterprise is developing the program of construction of the disinfection plant for wastewater.  Realization of this project will allow get good quality water, suitable for technical needs, reduce withdrawal of underground water and amount of contaminated wastewater.  Therefore, the next goal is reconstruction of operating treatment facilities, decreased consumption of drinking water for technical needs and reduced amounts of effluent discharge.

10.4.2. Description of mitigation measures

The enterprises of the town are currently supplied with technical water from the surface source (the Iput River).  It is followed by treatment at treatment facilities and water supply to consumers.  It was decided to increase the treatment level of wastewater and supply it for technical needs.

To improve the quality of wastewater, the program is being developed for “Construction of engineering-biological water-protective facilities in the CIty of Novozybkov”.  The cost of the program implementation is 7400 thousand roubles in the 2001 prices.  In the same time, the work has started on project “Reconstruction of system of the use of treated wastewater for technical water supply of enterprises of the City of Novozybkov”.

Realization of the above mentioned project suggests the following measures: decontamination of the whole volume of wastewater (3650 thousand m³/year) and the use of 1800 thousand m³ of treated water for technical water supply of the town.  They also include construction of conduit 300 mm in diameter from water decontamination station to the point of connection to existing pipeline of technical water supply.

Realization of this project will enable to reduce the volume of treated wastewater (up to 50%) discharged to the Korna River.  This will ensure enhancement of ecological condition of water bodies as well as gaining of economic benefits from realization of treated wastewater used for technical needs.

10.4.3. Investment Requirements

Development of environmentally sound operational conditions of wastewater treatment facilities, discontinuance of faecal discharge to water bodies and on the ground and extension the sewerage system to all rayons of the city require about 240 000 thousand roubles in 2002 prices.  However, the issue of extension of the sewerage system to all rayons of the city is not considered in the current program.

Financial requirement directly for construction of biological wastewater treatment facilities makes up 7400 thousand roubles, for decontamination of wastewater with subsequent use of the half of treated wastewater for technical water supply of the town makes up 7263 thousand roubles.

10.4.4. Feasibility Analysis and Recommendations

Economic substantiation of water protective measures is carried out by means of correlation of economic results of these measures with spending required for their realization.

The cost of averted damage caused by the pollution of water body (У_п), including increment of earlier loss of profit is accepted as economic result of water-protective measures.

The input data provided by the State unitary enterprise “Novozybkov Inter-District Engineering Services”:

- The cost of reconstruction of the scheduled complex of measures – 7263 thousand roubles.

- Total operational cost for the considered complex – 656 thousand roubles.

 

Calculation of cost efficiency of mitigation measures at Novozybkov Inter-District Engineering Services

Calculation of mono-pollutant (М).

М = _i  *  V_i = 654.8 c. t (see Table 10.11).

 

Calculation of total mass of pollutant, that pollution of wastewater at Novozybkov Inter-District Engineering Services will be reduced for within 5 years, is presented in Table 10.11.

M_a per year = 131 t

D_a = 8400 * 1.8 * 131 = 1980 thousand roubles

 

Calculation of increment of lost financial benefit I

I is assumed in professional judgment as 10% of D_a = 198 thousand roubles

E_e = 1980 + 198 = 2178 thousand roubles

 

Realization of project“Reconstruction of the system of use of treated effluents for technical water supply” will enable to get fees for withdrawal of 1800 thousand m³ of water and at the price 230 roubles for 1000 m³:

1800 thousand  230 = 414 thousand roubles / year

 

Table 10.11 : Annual Damage Caused due to Inefficient Treatment Facilities

 

To reduce the fee for effluent discharge:

1800 * 28 = 64000

 

According to the feasibility study by the vodokanal, the cost of 1 m³ of technical water is reduced by 1.19 rouble or by 212.2 thousand roubles annually.

The total profit is 742 thousand roubles annually.

The total economic result is 2178 + 742 = 2920 thousand roubles.

 

Calculation of the reduced costs

The reduced costs are calculated by formula:

DC_r = Т_c + 0.12 К,

e = 0.12;  K = 14663

The total operational costs are 646 thousand roubles.

DC_r = (0.12  * 14663) + 646 = 1760 + 646 = 2406 thousand Roubles

 

Calculation of net economic effect

DU = E_e - DC = 2920 - 2406 = 514

 

Payback period (T) for investments into the water-protective measures is calculated by formula

T = K / DU = 14663 / 514 = 28 years (with threshold of effectiveness at 14 years).

 

The reasons are the following.  The main effect from the complex of water-protective measures is provided by reduction in volumes of damage due to decreased amounts of pollution.  However, this reduction does not cover the costs of total upgrading of the obsolete assets of the vodokanal.

If we consider only the first one of these two projects, the one of reduction in the pollution level, it will be effective.

The other project – on disinfection of wastewater and its subsequent use for technical water supply – is very enticing and high-minded.  But due to the historically low water rates in Russia, it does not pay back formally within the given time.  In western countries, with their much higher rates, it would be highly effective.

The effective payback period for the investment into treatment facilities is less than 7 years.  Realization of this project will enable to reduce the volume of treated wastewater (up to 50%) discharged to the Korna River.  This will ensure enhancement of ecological condition of water bodies as well as gaining of economic benefits from realization of treated wastewater used for technical needs.