"EVEN IN AN EXCELLENT MANAGED SEWAGE WORKS,

THE APPLICATION OF AQUA CLEAN ACHIEVES SIGNIFICANT

BENEFITS AND IMPROVEMENTS"

Introduction
The sewage work of the borough Deutsch-Wagram is situated in the south west of the settlement on the left shore of the Rußbach and has been in operation since 1969. The drainage area is 350 hectare and the degradation performance is more than 90%. All accumulated waste water is cleaned by mechanical, chemical and biological treatment. At the moment only one activated sludge tank is used, the second one is used as storage tank for sludge. The quantity of water for a population equivalent of 8.1 is treated in the activated sludge tank, designed for a population equivalent of 6.000. Under the supervision of the Erich Hlubik, the sewage works’ technician, there has been steady improvements made to the system to investigate new methods and cost saving techniques, AQUA CLEAN™ was introduced in co-operation with the company Stuhl & Stuhl in Vienna.

Components of the Sewage Work of Deutsch-Wagram- Screw pump, screen, circular degritter, distributor structure, two activated sludge tanks à 1400 m3, secondary settling tank 2.300 m3, sludge recycling pump station, iron sulfate solution tank, sludge storage tank, sludge de-watering and plant site.

Operation of the Sewage Work of Deutsch-Wagram- The waste water entering the sewage work at the supply tank is lifted up with screw pumps to the level of the sewage work and passes the screen. By a mechanical scraper coarse matter is removed from the waste water. Then the waste water flows through the circular degritter where granular components are separated.

Through a distribution system, the waste water is mechanical pre-cleaned and enters the activated sludge tank with a capacity of 1440 m3. The biological treatment is carried out by the activated sludge process. To assure the oxygen demand, air is supplied with cage rotor aerators in the waste water. In the secondary settling tank, with a capacity of 2.300 m3, the sludge settles down and is separated from the waste water, cleaned biologically, which is then discharged to the receiving water (Rußbach). Through a syphon pipe the settled sludge enters the sludge recycling pump station. With screw pumps the sludge is pumped back into the activated sludge tank.

The chemical cleaning is carried out with the addition of iron salts to precipitate phosphorous from the waste water and is removed with the excess sludge from the process. Under corresponding plant operations, Nitrates can also be removed (denitrification) with high efficiency from the waste water. The sludge is thickened in the sludge storage tank and the sludge liquor pumped back into the supply tank. The thickened sludge either can be directly used in the agriculture or the produced sludge granulate is scattered on the fields after de-watering with a Bellmer sludge press.

Operation Characteristics of the Sewage Work of Deutsch-Wagram

Table 1. Average of some parameters from the annual report of 1997 

Dosage Schedule for AQUA CLEAN™ in the Sewage Work of Deutsch-Wagram

Dosage of AQUA CLEAN™ depends on through-flow, retention time, size (volume) of the sewage work (activated sludge tank, secondary settling tank, etc.), and the loading (COD; BOD) of the system. The dosage and schedule plan for the application of the sewage work of Deutsch-Wagram was suggested by the use of the data given.

1 US gallon = 1 bottle = 3,7853 liter

If required, AQUA CLEAN™ is applied additional in the pump station, supply tank, secondary settling tank and sludge storage tank. The addition is carried out either by direct applying or spraying in a dilution of 1:10 to 1:50 with water.

Application of AQUA CLEAN™ in the Sewage Work of Deutsch-Wagram

If required (seasonal depending high inflow rates) at the pump station, into the supply tank and into the secondary settling tank AQUA CLEAN™ is applied additional.

Improvements Achieved by the Application of AQUA CLEAN™ in the Sewage Work of Deutsch-Wagram

Although management and functioning of the sewage work operates very well, excellent parameters in the degradation performance of the cleaned water in the discharge, significant improvements with a reduction of the manpower was found:

Results of the Sludge Pressing in the Sewage Work of Deutsch-Wagram

To get representative values, comparatively values from the period of the previous year, 28.7.-7.8.1997, were used. The sludge pressing process was carried out with a Bellmer sludge press under the firm of Reinpold.

Table 2. Results of the sludge pressing obtained from 24.7-1.8.98 

The values listed in table 2 show impressive results, even in an excellent managed sewage works, the application of AQUA CLEAN™ achieves significant benefits and improvements.

The slurry sludge could be pumped out easily and only insignificant residues in the tank and on the walls are visible. De-watering and the pressing process of the coarse sludge particles were carried out without troubles. The resulting press-cake is granular and easy to compost. 

Beside the reduction of the environmental loading, care of mechanical parts, working and removal costs were reduced in this connection. The costs for AQUA CLEAN™ are only a fraction of this cost savings.

Alternative an offer for a treatment with enzymes was made by another competitor. In comparison the costs for this treatment would be the triple of the price for AQUA CLEAN™.

Enzymes are, compared with AQUA CLEAN™ no living bacteria, only very specific reactions are supported by them. Enzymes are most fixed on nutrients where bacteria slowly settle down and then they actually carry out decomposition processes. AQUA CLEAN™ contains living strains of bacteria, adapted to stress situations, well suited with very effective digestion and decomposition processes. They start to break down organic wastes immediately after application. They produce needed enzymes by themselves and can adapt the production of special enzymes to organic wastes present (constitutive, inductive).

For system startup, recovery from upset or shock loading AQUA CLEAN™ is best suited.

The successful application of AQUA CLEAN™ in the sewage work of Deutsch-Wagram is continued and changes will be noted. Analysis of the inflow and discharge waste water are made periodically and are documented. Qualitative and quantitative results about improvements and savings are added as supplement continuous.