Then : DOSFOLAT® treatment time 90 days .Today with DOSFOLAT®XS within 28 days

The treatment plant of a petroleum refinery in the State of North Rhine-Westphalia was overloaded with 51,000 population equivalents (EGW) and experienced a continuing series of breakdowns. Despite upgrading the treatment plant at a cost of DM 350,000, the effluent COD remained at an unacceptable level between 700 and 900 mg/l.
DOSFOLAT® was added to the plant and the effluent COD values over the following 90 days of normal operation are shown in Figure 4.
Within 90 days from the introduction of dosfolat®, the effluent COD decreased from 700 - 800 mg/l to below below 300 mg/l. The operator wrote us, saying :

"...dosfolat(R) has been in use since March 1, 1988. Initially the
test was not successful becauseDOSFOLAT and an Fe-precipitant were being introduced at the same location. Furthermore it was ascertained that the well water had a high iron content, and was therefore not suitable for diluting the DOSFOLAT.

Success was achieved once these problems were eliminated. The operating parameters have been stable since about the beginning of May.

The sludge volume index, a major problem, sank from about 400 ml/g to about 150 ml/g. The amount of sludge wasted decreased by 30 % and the sludge was considerably easier to dewater.
The belts of the vacuum filter press need to be cleaned only once per quarter instead of once per month. The effluent COD and especially BOD5 decreased substantially.
The dosfolat dosage rate was 0.1 ml per kg COD in the influent (for an influent of 2,500 kg COD, 250 ml of dosfolat and 100 l of municipal tap water were mixed in a storage tank and introduced at the inlet to the aeration basin at a rate of 70 ml/min)....."

Fig. 4 Germany: Mineral oil refinery STW performance results with DOSFOLAT®
Vertical axis: Effluent COD
Horizontal axis: Time in days