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SPINE LCI dataset: Treatment of oil-contaminated waste water

Administrative

Technical System

System Boundaries

Flow Data

About Inventory


Administrative
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Finished Y

Date Completed 1999-04-15

Copyright

Availability Public


Technical System
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Name Treatment of oil-contaminated waste water

Functional Unit 1 m3 of oil contaminated wastewater from the oil treatment.

Functional Unit Explanation The water treatment facility is seen as a subsystem to the oil treatment for treatment of the oil contaminated wastewater generated at this facility.

In 1997 the received water had the following origin:
Industries and municipalities 600 m3
Surface water system 129 012 m3 (1101 m3 from Skarvik)
Ballast- wash- and slopwater from vessels and tankers 16 811 m3
Emulsions from industries, municipalities and gas-stations 1739 m3
Cisterns 16 807 m3 (11 310 m3 from Skarvik)


Process Type Gate to gate

Site CICLEAN AB Box 48047 41821 Göteborg Sweden

Sector Waste treatment

Owner CICLEAN AB Box 48047 41821 Göteborg Sweden

Technical system description The water treatment facility receives and treats oil-contaminated water from ships and some oil wastes and emulsions from industries in the western parts of Sweden.

The waste water is first collected in tanks before filtered where the oil phase is separated from the water. The water phase undergoes two treatment steps, first a flocking tank and later sand filters, before it is let out into the recipient. The oil phase from the reception tank is treated in a settling tank where water is further separated.

The cleaning process is based on chemical precipitation with aluminiumsulphate, flotation and sand filtration. The aluminiumsulphate is recycled with up to 80 % and derived oil is pumped to a storage tank for further transportation to a certified external receiver. (The transportation is not a part of the systems function.)

Within the plant there are two tanks, each with a capacity of 10 000 m3, used for receiving ballast water and other oil-contaminated water, one processing tank (2000 m3), a so called settling tank used for separating oil and water and one storage tank (1500 m3) used for separated oil. The plant also has six smaller receiving tanks (2 at 230 m3 and 4 at 50 m3) to increase the facility’s flexibility and possibility for separate treatment of particularly contaminated water. Some of the receiving tanks are provided with heating and has the possibility to draft at the top.

Oil-contaminated water, e.g. ballast water is pumped from ships to the receiving tanks. Oil-contaminated water from surface water systems within Skarvik- and Rya harbours is also pumped to these tanks. Oil-contaminated water from industries, municipalities and petrol stations is collected and transported by truck to the facility, where it is pumped into the receiving tanks. (The transportation is not a part of the systems function.)

Scrap is derived through filtering. As the scrap is combustible it is sent to Sävenäs, a waste fuelled power plant.
The oil phase, which eventually is formed at the top of the receiving tanks, is transferred to the settling tank. Sludge from ships and the top phase from oil separators within Skarvik- and Rya harbours are also transferred to this tank. The top phase may contain gasoline and other petrol products.

In the settling tank water and oil are split under the influence of heat and the addition of Petrotec RI-54. The derived oil is pumped to a storage tank for further transportation to a certified external receiver. The water goes into the plant.
In the plant the oil is separated by chemical precipitation with aluminiumsulphate. The pH is adjusted with caustic soda to 6,5. This is done automatically and is controlled by a pH-electrode. The precipitated contamination is flocked in the flocking tank. Polyelectrolyte (Magnaloc LT 27 AG) is added to optimise the flocking. The cleansed water is pumped to the clean-water tank through four sand filters. Water from this tank is also used for back flushing of the sand filters. The back flushing water is gathered in a tank for dirty water, from where the water is pumped back to the cleaning plant. The cleansed water is later on let out in Götaälv through a control plant where the flow, pH and oil contents are measured continuously. There is also an automatic testing device situated in the control plant, which takes specimens proportional to the flow.

If the incoming water does not contain emulsified oil the water is pumped to the two flotation plants. To the flotation water/air-dispersion at the pressure of 5 to 6 bar is used. The cleansed water is pumped to the clean-water tank and later on let out in Götaälv.

The separated oil-containing sludge from the plant is pumped to the recycling tank, where it is heated to 60ºC. The sludge is then mixed with sulphuric acid to get pH approximately to 1. This makes the oil separate from the aluminium hydroxide and float up to the surface. The oil is then send to the storage tank (see above).
The water phase, which consists of an acid aluminiumsulphate-solvent, is pumped back to the plant where the chemicals can be re-used to clean the emulsified water.


System Boundaries
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Nature Boundary Resources that are not seen as limited in Sweden are neglected e.g. land usage and fresh water.

The company is legislated to measure the following emissions:
Mineral oil
TEX (aliphatic)
COD
Phenol

Time Boundary The study only deals with retrospective data and no attempts are made to predict future events or conditions. 1997 is assumed as a suitable time frame to collect and interpret data.

Geographical Boundary The geographical boundary set to Sweden.

Other Boundaries Cut-off criteria
The environmental impact from capital goods and activities serving the process are neglected e.g. personell, infrastructure and facilities.
Moreover, maintenance and wear down of the system are neglected.
Is is assumed that there occurs no spill at the plant.

The chemicals Magnaloc LT 27 AG and Petrotec RI-54 are accumulated in the oil. As the oil leaves as a product their impacts on the environment can not be estimated as emissions at the water treatment facility. The impact that they cause depends on how the oil is used. It is although important to keep in mind that those chemicals has contaminated the oil and should be taken under consideration when emission is calculated for combustion of the product.

The oil percentage in the incoming water is thought to be so low that no sedimentation occurs in the receiving tanks. The only sedimitation that occurs at the facility is caused by the derived oil in the storage tank.

Scrap derived from filtering is not taken under consideration. As the water from the oil treatment already has been filtered at this facility it is considered to be free from scrap when it is pumped to the water treatment facility.

The production of electricity used in the system has not been included.

Allocations The facility treats various kinds of water but they are all considered to have the same resource use and emission per m3. As described for the functional unit; only the resource use and emissions from treatment of the wastewater from the oil treatment facility is of interest, therefore are only those impacts accounted for.

Systems Expansions


Flow Data

General Activity QMetaData
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Date Conceived 1997
Data Type Unspecified
Represents
Method Data are acquired from study of the environmental report of 1997 and inquires to the employees at the facility. Emissions of hevy metals are modelled from data in the environmental report for Reci Halmstad. This is done due to unsufficient data about these emissions. The modelled data has been taken from the incoming water to the water treatment.
Companies hired for analysing the specimens taken are;
Svenska Saybolt AB, Kemanalys AB and Analycen AB.


The subtances are divided with the total amount of recieved oil-contaminated water (164 969 m3) to represent amount per functional unit.

Literature Reference

Notes

Flow Table and Specific Meta Data
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QMetaData Direction FlowType Substance Quantity Min Max SDev Unit Environment Geography

Input Refined resource Aluminium sulphate 0.051 kg Technosphere Sweden

Input Refined resource Electricity 1.397 kWh Technosphere Sweden

Input Refined resource H2SO4 0.074 kg Technosphere Sweden

Input Refined resource Magnafloc LT 27 AG 0.0047 kg Technosphere Sweden

Input Refined resource NaOH 0.0954 kg Technosphere Sweden

Input Refined resource Oil-contaminated waste water 1 m3 Technosphere Sweden

Input Refined resource Petrotec RI-54 0.0012 kg Technosphere Sweden

Input Refined resource Thermal energy 6.471 kWh Technosphere Sweden

Output Emission Aluminium sulphate 0.0508 kg Ocean Sweden

Output Emission AOX 0.1586 g Ocean Sweden

Output Emission Aromatics 1.8296 g Ocean Sweden

Output Emission Cd 0.002 g Ocean Sweden

Output Emission COD 615.97 g Ocean Sweden

Output Emission Cr 0.049 g Ocean Sweden

Output Emission H2SO4 0.0706 kg Ocean Sweden

Output Emission HC 36.59 g Air Sweden

Output Emission Mineral oil 3.049 g Ocean Sweden

Output Emission NaOH 0.0954 kg Ocean Sweden

Output Emission Ni 1 g Ocean Sweden

Output Emission Pb 0.01 g Ocean Sweden

Output Emission Phenol 0.9148 g Ocean Sweden

Output Emission TEX (aliphatic) 12.197 g Ocean Sweden

Output Emission Zn 1 g Ocean Sweden

Output Product Waste oil 0.03 m3 Technosphere Sweden

Output Product Water 0.9698 m3 Ocean Sweden

Output Residue Oil-sludge 0.0001 m3 Technosphere Sweden


About Inventory
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Publication Master thesis: ’’LCA on converted fuel oil’’ by Daniel Strandberg and Christer Wik, MSc students
Technical environmental planning, Chalmers Univeristy of Technology

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Data documented by: Daniel Strandberg and Christer Wik, MSc students, Technical Environmental Planning, Chalmers University of Technology

Documentation reviewed and classified by: Ann-Christin Pålsson, CPM/TEP, Chalmers University of Technology
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Intended User Internal use at Reci Industri

General Purpose The objective of this study was to carry out a Life Cycle Assessment for converted fuel oil. The analysis involves outlining the environmental hazardous steps in the production. The result will be used internally to aid as an environmental improving guidance as well as to receive a better view of the process. Externally the result is a part of Reci’s ISO 14000 certification, which acts as a guarantee to the customers. The quality of the inquiry is set due to the standards of a Master of Science thesis.

Detailed Purpose To estimate the resource use and emissions released treating oil contaminated water.

Commissioner Schaff, Lars, environmental managerReci Industri AB Box 48047 418 21 Göteborg Sweden.

Practitioner Strandberg, Daniel and Christer WikMSc students Technical Environmental Planning Chalmers University of Technology 41296 Göteborg Sweden.

Reviewer Beckman, TorstenTechnical environmental planning Chalmers University of Technology 412 96 Göteborg Sweden

Applicability The data represented are site-specific and are only valid for treatment of wastewater from Skarvik.

As the incoming water is of very varying composition and quantity the impact per functional unit may vary quite much.
The data shall therefore be seen as estimation of the impacts made.

The chemicals Magnaloc LT 27 AG and Petrotec RI-54 are accumulated in the oil. As the oil leaves as a product their impacts on the environment can not be estimated as emissions at the water treatment facility. The impact that they cause depends on how the oil is used. It is although important to keep in mind that those chemicals has contaminated the oil and should be taken under consideration when emission is calculated for combustion of the product.

About Data The oil-sludge, caused by sedimentation in the oil storage tank, is derived when the tank is cleansed. As this is not an every-year-procedure the amount of sediment per cubic metre has to be estimated. The waste-oil is supposed to cause sedimentation of 0,25% at Reci’s facility in Halmstad. The data is supposed to be representative for the sedimentation at Reci Göteborg as well, calculated on the amount of treated oil.

Mass balance
Input approximately 165 000 m3.
Output about 163 200 m3.
Difference 1800 m3.

When put into perspective of the total inflow the difference can be assumed to be a measurement error. As the treatment of oil-contaminated water is a continual process and flows are only measured when entering or leaving the system it is also plausible that an significant volume was still in the system when inflows and outflows where reported. The most likely explanation is a measurement error on the inflow and outflow of water. The total inflow was 164 969 m3and the total outflow 158 214 m3. To achieve mass balance the inflow is supposed to be 1000 m3 lesser and the outflow 800 m3 more.



Notes The reviewer acted as supervisor for the Master thesis: ’’LCA on converted fuel oil’’

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© CPM, Chalmers University of Technology, 2014


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