Alken Clear-Flo 7008 Controls Odor and Aids Compliance for Large Greek Oil Depot

Background:

In 2002, a large Greek Oil Depot Station's sequential batch reactor (SBR) experienced difficulties adjusting to hydraulic fluctuations in their raw wastewater, with feed varying from twice a week to once every ten days.

One stream of wastewater in the plant derives from the drainage water collected from the bottom of the collection tanks. This "dirty water" containing petroleum, benzene and jet fuel, is a portion of the ballast water used by oil tankers to travel back to the Greek Refinery in Athens, where they load their new fuel cargo for transportation back to the relevant Depot Station.

Oily polluted rainwater, called "first flush", from dirty surfaces at the 0.50 hectare in the depot station, supplies a second stream of pollution to the SBR plant.

To treat this system, bacteria were required that could quickly adapt to substrate and hydraulic fluctuations. Bio-Best gents Sotiris Stassinos and Alina Simeonaki and Alken-Murray's Valerie Anne Edwards decided to test therecently improved formulation of Alken Clear-Flo 7008 (formulation improvement in the fall of 2001) in this application.

Influent Characteristics:

Flowrate=20-150 m3/week
BOD5=500-800 mg/l
COD=1.500-2.200 mg/l
Lubricants and hygrocarbons (oils)=500-1.100 mg/l
Suspended solids=50-120 mg/l

The wastewater treatment plant consists of the following:

1. Balance tank
2. Tilted plate separator
3. pH adjustment tank
4. Coagulation and flocculation tank
5. Induced air flotation tank
6. Sequential Batch Reactor (SBR)
7. Rapid sand filter
8. Activated carbon filter
9. Drying beds

Initial Treatment - The SBR Wastewater System

 Alken Clear-Flo 7008 was fed in the biological tank during start up and commissioning period. After one week of treatment, the BOD removal efficiency was greater than ninety-seven percent and COD removal exceeded eighty percent.
With these results, the Depot station was finally able to obtain an Operation permit from the local authorities. Treatment was continued, with small maintenance doses for another four months.

Treated effluent characteristics:
BOD <5 mg/l
COD <80 mg/l
Lubricants and hygrocarbons (oils) <10 mg/l
Suspended solids <10 mg/l

Second Treatment - Odor Control in Stagnant Storage Tanks

Intermittent operation of the treatment plant caused the oily wastewater to remain stagnant in all the tanks (apart from SBR where it was constantly aerated) sometimes for as long as one to two weeks. During summer heat, this practise resulted in offensive odors traveling from the partly covered tanks in a radius of 300 meters from the plant, causing complaints from neighbors.

BIOBEST advised that small dosages of CF 7008 should be added to the odor emitting tanks and wells. After 24 hours of treatment with CF 7008, the bad odor disappeared and small air bubbles were released from the botton of the relevant tanks and wells. The client now applies preventative treatment of small doses of CF 7008 whenever water is expected to remain stagnant for more than one day. No more problems with offensive odors have been reported since treatment began.

E-mail Alken-Murray Corp.: clearflo@alken-murray.com