… and Production Wastewater from Oil Products
How to make efficient use of wastewater and contaminated water? This question is raised by the ships and enterprises owners due to the following two reasons:
- Environmental – a continuous reduction of MPD and MPC (maximum permissible discharge & concentration) due to increased environmental requirements.
- Economical – regular increase of water costs for the enterprise’s needs.
Wastewater is classified into the following groups in accordance with the source of origin:
- Production (industrial) wastewater (originating from technological production processes) is discharged through industrial or general sewer system.
- Domestic (household) wastewater (originating from domestic activity)
- Surface wastewater (divided into rainwater and meltwater – originating from melting of the snow, ice and hail) is usually discharged through the stormwater sewer system.
- Ships’ (bilge) water originating from the ships’ tanks shall be disposed in the ports of entry.
As a result of utilization of the typical systems for water treatment from oil products, the enterprises are using vast areas and keeping a lot of staff and service personnel.
Treatment of bilge water is not doable without additional energy costs, which is usually not a cost-efficient option.
Aiming at reducing the costs born by enterprises for maintenance of these facilities, energy costs and costs for sustaining the operating mode of complicated equipment that are included into the end-product costs, our experts have developed stationary facilities that are installed at oil containing water mainlines. This complex of mainline facilities (as seen in Figure 1) allows solving the issue of treatment of oil containing water from hydrocarbon fractions and mechanical impurities without any additional costs.
Figure 1. Treatment facility of water from oil products and mechanical impurities.
1 – Stage of pretreatment from mechanical impurities – 10-50 micron
2 – Stage of fine treatment from oil products
The main operating unit of the facility is a filter with filtering elements – Cribrol cartridges (Figure 2). Filter consists of a case with the upper lid for installation of Cribrol filtering cartridges. Filtering cartridge consists of a special composite material of a hollow cylindrical shape (310 x 165 mm) with 1 or 2 fixing discs depending on the design option (through/non-through). Water to be treated enters the filter through the inlet pipe and passing through the filter fills the bottom of the separation chamber, where the treated water comes from through the bottom outlet pipe, and enters the technical water mainline.
Figure 2. Main processes of separating water from oil products/gases in the separation chamber of the filter.
Mechanical impurities are left in the inner part of the cartridge, and oil droplets separated from water are getting bigger and rise to fill the upper part of the separation chamber. When required, the accumulated separated oil products are removed from the separation chamber through the upper discharge pipe to the oil products collector.
Our special composite material allows for effective removal of oil products, mechanical and biological impurities from water.
In order to prove the effective operation of the water treatment facility we have collected samples of oil containing water before and after treatment with Cribrol filter (Figure 3).
Figure 3. Results of oil containing wastewater treatment at Cribrol mainline facility after one flow through the separation cartridge.
The results of the water testing for content of oil products before and after treatment in mg/dm3 are presented in the table below:
|Water sample||Results||Errors in measured data, +||Test assessment reference|
|Before filter||2562.5||256.2||PNDF 14.1:2.5-95|
Water testing in accordance with environmental normative PNDF 14,1:2,5-95 showed reduction of oil products concentration in water from 2562.5 mg/dm3 to 1.29 mg/dm3, which corresponds to the requirements to the feed water at the oil refining enterprises – below 1.5 mg/dm3 and requirements to the water discharged to the municipal sewer – below 5 mg/dm3.
Extracted oil products are drained to the storage tank for further usage. There is no water in separated oil products.
We have conducted a test with artificial water-fuel emulsion, in order to determine effectiveness of Cribrol cartridges in case of the highest concentration of oil products in contaminated water. On the basis of such test we have detected that Cribrol cartridges are capable to separate water-fuel emulsions with more than 50% concentration of oil products in water.
Figure 4. Result of treatment of the diesel oil emulsion:
- Diesel fuel – “standard”.
- Emulsion: water – 43%, diesel fuel – 57%.
- Treated diesel fuel (water content – 05%).
- Water separated from diesel fuel
Provided below in Figure 5 results of effectiveness of Cribrol cartridges in accordance with ISO-16332 allow us to declare versatility of this technology with respect to water-fuel emulsions.
Figure 5. Comparative graph of performance figures of EU filter elements and Cribrol cartridges during tests in accordance with ISO-16332.
X axis – Water content in diesel fuel, %
Y axis – Effectiveness of water separation, %
Based on the capacity of Cribrol cartridges to separate technical water with various content of oil product (from 1% to 99%) and get two fractions with precise interface (oil product/gas – water) after such separation, we conclude that technologies developed by us can be used for treatment of oil containing water. This can be proved by successful operation of our equipment that is notable for its mobility, small size, zero energy consumption and simple servicing.
Equipment based on Cribrol cartridges is an effective solution to the problem of reuse of oil containing water at many production objects of various economic sectors.
Current operational track record of our equipment in the industry
- Treatment of light oil products from water and mechanical impurities (production, transloading, storage).
- Treatment of oils from water and mechanical impurities (production, transloading, storage).
- Treatment of gases from dropping liquid (production, transloading, storage).
- Separation of water from hydrocarbons (in any percentage).
- Washing out storage tanks (zero waste recirculating systems that allow to treat transloading, storage and transportation tanks in the shortest term).
- Treatment of oil products and gases of any density from mechanical impurities (cartridges of various micron size – from 10 to 1000 micron).
- Oil recovery
- Fuel conditioning.
Some Modifications of Cribrol Units