A. M. KONOKH, director; G. N. SHESTAKOVA, head of production and technical department association of the Municipal Unitary Enterprise «Gorvodokanal» (city of Novoaltaysk)

APPLICATION OF ECOPOLYMER DIFFUSERS IN ALTAI

The issues of improvement of the sewage treatment plant functioning efficiency of the city of Novoaltaysk have been in the focus of attention of the Municipal Unitary Enterprise “Gorvodocanal” literally from the very first day of its functioning.

The sewage treatment facility complex of the city of Novoaltaysk has been exploited since 1979; its design output being 33 ths. m³ per day. The composition of the complex is: comminuting screens, radial primary settlers (3 units); aerotanks (3 sections), radial secondary settlers (3 units), airblower unit, chlorinating, pump transit of the treated sewage to the river Ob, all those allow to carry out the full cycle of biological cleaning.

The aeration system had become virtually non-operable by 1997. Filtering channels had been shut down by 70% and aeration was carried out through T-shaped perforated pipes, and only 30% of the filtering channels supplied air through the filtering plates.

In 1997-1998 aerotanks were reconstructed, their bottoms were fully rebuilt and encased in concrete. The aeration system had been changed into pipes with polyethylene dispersive coating of the firm “Ekopolimer” production.

The advantages of the introduced aeration system:

• High mechanical reliability of the aerators and their connections allows tolerating water hammers and that is why careful and gradual blower actuation is unnecessary;
• There are no water ejecting risers under the introduced aeration system, since after the shutdown and subsequent blower actuation the sewage is easily pressed out of the aerators. The absence of the water ejecting risers considerably facilitates exploiting the aerotanks, especially in wintertime. One doesn’t have to warm up the latches by a blowlamp, to open them by turns etc. The new system allowed reducing the personnel by three operators;
• During the three years of the aeration system exploitation the aerotanks have neither been shut down for repairs, nor there have been any swashes.

There has been no energy saving because there has been one blower in operation and the same blower has been used for retaining the sludge in suspension, though just half of the blower’s output is sufficient for oxygenation.

In fact, the aeration system reconstruction had turned out to be the basement on which we later founded our subsequent large-scale improvements in the station functioning.

After the aeration system replacement in all three aerotank sections there had been implemented the adjustment of all sewage disposal facilities and aerotanks, in particular, attracting the professionals from the City Unitary Enterprise «MosvodokanalNIIproyekt» for alteration of blowing of the sewage, air and recurrent activated sludge.

Implementation of the above mentioned measures allowed carrying out a considerable sewage quality improvement before they are discharged into the river Ob. The average concentration of the contaminating agents is given in the following table:

The nitrification process now goes much deeper and the process of denitrification occurs in the lower corridors of each three sections of the aerotanks, because the aeration system allows implementing the necessary air supply volume through the aerotanks’ corridors.

The introduction of the progressive aeration system let tackle further aerotank reconstruction with the introduction of polymeric charge to the clarified water in front of the aerotanks, offered to the “Vodokanal” by the professionals from the City Unitary Enterprise «MosvodokanalNIIproyekt», which will let to improve the clarified water quality up to the standard of a fish industry basin. The polymeric charge is now being installed.

The cooperation of the Municipal Unitary Enterprise “Gorvodocanal” of the city of Novoaltaysk with the research and production firm “Ekopolimer" is of a long-term character and is based on a mutual trust and mutual aid. Thus, in 1999 with the assistance of the research and production firm “Ekopolimer" we acquired and installed at 4 sewerage and pumping stations monoblock sewage pumps of the Swedish firm ABS with the capacity of 127-235 m³ per hour, the introduction of these pumps allowed reducing 7 workers (of 14) and saving energy of 250 ths. kw per year and wages for 130 ths roubles per year.

As a result of our longstanding cooperation with the research and production firm “Ekopolimer” the water pollution payments alone has decreased for 50 ths. roubles per year (90 instead of 140) in comparison with the years 1997-1998. On the whole, the Municipal Unitary Enterprise “Gorvodocanal” of the city of Novoaltaysk enjoys an annual economy of 300 ths. roubles, which equals to a monthly salary fund of the entire enterprise.

We believe that the implemented reconstruction of the aeration systems has measured up in full both technically and economically.