Up to 99.5% Oil Recovery from Refinery Waste

Oil Recovery Systems

There is money in slop oil. Our automated oil recovery system reclaims up to 99.5% of the contained hydrocarbons, turning waste into profit. You will save money from minimized discharge costs and earn money from valuable oil at the same time. Find out all details below.

1-Inlet pump, 2-Tricolor® dosing device, 3-Sludge mixing reactor, 4-Oil/water separation system, 5-MBR filtration system, 6-Water heating & circulation system, 7-Oil/solids separation system, 8-Control unit

Turning Oil Waste into Profit

Oil waste comes in many forms, but it always causes trouble. Besides being harmful to the environment, it poses a serious financial dilemma for any operator:

  • Storage and disposal of hazardous oil waste causes substantial costs.
  • The often large amounts of oil contained in oily waste cannot be sold and thus have to be written off as lost earnings.

This is where the Zaopin ST sludge oil recovery (SOR) system comes in.

Specifically designed for the efficient recovery of oil from oil waste, the Zaopin SOR system extracts close to 100% of contained hydrocarbons in a fully automated process, thereby turning toxic oil waste from refineries and drill sites into non-hazardous solids.

Even more, the recovered oil which is essentially free of impurities can be sold as valuable product. This advantage makes Zaopin SOR a system that pays for itself.

Wide Range of Application

The Zaopin SOR system is suitable for the treatment of a wide range of oily waste and especially excels at recovering oil from waste with high solids contents.

The following categories broadly describe the scope of application:

Drilling waste: Recovery of oilfield and drilling mud waste oils such as

  • Oil-based mud (OBM)
  • Oil-based fluids (OBF)
  • API separator sludges
  • Oil-contaminated soils

Oil sludge: Recovery of sludge and tank bottoms from crude oil storage tanks, sludge tanks, and tank bottom pits.

Slop oils: Recovery of waste and secondary oils from oil refineries often stored in sludge lagoons, pits, and sumps.

99% Oil Recovery

The Zaopin SOR system is able to reclaim up to 99.5% of hydrocarbons from oil waste such as oil-based drilling mud or slop oil.

The returned oil is of high purity and can be reused or sold downstream. Even with the current low price of oil the profits generated by treating hazardous oil waste with the Zaopin sludge oil recovery system can be significant.

How Clean is the Final Output?

The effluents oil, water, and inorganic solids returned by the Zaopin ST SOR system are very clean. In fact, the ability to cleanly separate the sludge into its components is what makes this system so effective.

The high purity of the effluents gives the oil product a high market value, while the effluent water and solids are classified non-toxic and can be safely discharged.

The following section describes the level of purity for each effluent in more detail.


Containing only traces of water and solid particles, the hydrocarbons extracted from the sludge are of high purity and can be safely reintroduced into the refinery process.

Effluent Zaopin SOR
Effluent Oil BS&W < 1%

BS&W: Basic Sediment and Water. The total amount of residual water and solids, quantified as a volume percentage of the oil.


The effluent water from the Zaopin SOR system is safe for direct discharge and exceeds even the strict requirements of the German waste water directive (Abwasserverordnung - AbwW) with regards to oxygen demanding substances.

Effluent Zaopin SOR German Waste Water Directive
Discharged Water BOD < 10 mg/l
COD < 50 mg/l
Ammonia < 10 mg/l
TSS < 10 mg/l
PH 6-8
BOD ≤ 15 mg/l
COD ≤ 75 mg/l
Ammonia ≤ 10 mg/l

BOD: Biological Oxygen Demand. Indicates the content of oxygen needed to decompose organic compounds in wastewater by bacteria. Test method used: BOD5
COD: Chemical Oxygen Demand. Indicates the amount of oxygen needed when all organic ingredients would be oxidised completely.
TSS: Total Suspended Solids. The amount of solid particles suspended in a liquid.


With a residual hydrocarbon content of only 0.5-1%, the solids discharged from the Zaopin oil waste remediation system are non-hazardous and can be easily disposed of at a common landfill at much reduced costs.

Effluent Zaopin SOR
Discharged Solids Oil contents 0.5-1% PH:6-9

Significant Time Savings

In its standard configuration, the Zaopin ST soil remediation system processes 2 m3 of oil laden solids per hour. This throughput can be further raised to up to 8 m3/h simply by connecting more reaction tanks.

To give you a better impression about the performance of the whole system, the following table shows the capacity at several key processing points:

Treatment Process Equipment Capacity
Soil Input & Washing Reaction tank 2, 4, 8, custom m3/h
Exhaust Gas Collection Condenser, activated carbon 600 m3/h
Oil Recovery Oil skimmer 2-3 m3/h
Water Pre-Treatment Oil/water separator 8-10 m3/h
Water Discharge Membrane bioreactor 0.5-1 m3/h
Solids Discharge Solids/liquid separator 5-8 m3/h

Competitive Advantages

Broad Scope of Application

  • Oil sludge from tank bottoms, sedimentation ponds, and oil lagoons
  • Oil-based drilling mud (OBM) and oil-contaminated drilling waste
  • Oil-laden soils

Easy to Use

  • Fully automatic oil recovery system
  • No additional pre-treatment of oil necessary

Safe Operation

  • Fully automatic operation minimizes points of failure
  • Construction and installation to ATEX 114 (former ATEX 95)
  • Operation in accordance with ATEX 137


  • High throughput for shorter cleaning times.
  • Reclaims up to 99.5% of hydrocarbons from the sludge or drilling mud.
  • Non-toxic effluent solids and water means reduced costs of disposal
  • High quality oil reclaimed from the waste can be sold old as a valuable product

Small Footprint

  • Only two 20' standard containers in size in the default configuration.
  • Containerized module system for fast installation, even in remote areas.

Environmentally Friendly

  • Toxic oil waste is turned non-hazardous solids.
  • Closed-loop cleaning system for emission-free operation.
  • Non-toxic effluent solids and water can be disposed of without further treatment.

How it Works


In its standard configuration the Zapin SOR system comprises of a reactor module and a separation module, both the size of a 20' standard container. This mobile design allows the equipment to be mounted on any truck and easily be transported to even to the most remote locations.

When the cleaning system arrives on-site, the reactor unit is connected to the separation unit and a heat source is added.

Fully Automated System
The Zapin SOR is a fully automated system: Once inside the reaction tank, the oil waste is separated into its oil, water, and solids phases in a self-running process.
Minimizing manual operation reduces the treatment time and ensures a consistent high quality of the effluents.


Oil waste such as oil-based drilling mud, tank bottoms, or slop oil is mixed with water and pumped into one of the reactors of the reactor module. Then a small amount of the Tricolor® washing agent is added to the oil/water mixture via an automatic dosing system.

Tricolor® is our proprietary washing agent. Its ability to transform long hydrocarbon chains into smaller ones significantly increases the efficiency of the separation process. Being plant-based, it is non-toxic and 100% biodegradable.

Next, the contents of the reaction tank are heated up and kept in motion for several minutes with the help of an agitator.

During this incubation time, the second reactor tank is filled and the washing agent is added.
By alternating between both reaction tanks, oil waste can be added at a constant flow, resulting in a more efficient separation process.

After the incubation time, the oil, water, and solids phases from the oil waste are clearly visibly, indicating the success of the initial separation.


The following automatic cleaning steps remove most of the impurities from the oil, water, and solids phases to make sure the oil can be sold as valuable product, while the effluent water and solids can be easily disposed of without further treatment.

Solids Phase: The solid matter present at the bottom of the reactor is transferred to an 2-phase decanter that separates solid particles from residual oil. The resulting effluent solids only contain 0.5-1% of hydrocarbons and can be safely disposed of on a common landfill.

Oil Phase: The oil phase is fed into an 2-phase separator to remove any residual water (The oil originating from the solids separation process is also directed here). The cleaned oil is then discharged and can either be reused (in case of oil-based drilling mud) or fed into the refinery pipeline.

Water Phase: The water first flows into a pre-treatment unit for removal of any residual oil (The water originating from the oil separation process described above is also directed here). As long as there is solid oil waste added to the system, the water is then pumped back into the reaction tank and reused as a washing medium.

Water Reuse: The water is kept inside a closed-loop system where it is being reused as a washing medium over and over again until all oil waste has been processed.
This design allows us to consume only a minimal amount of water in the oil recovery process

When the remediation of the solid oil waste has finished and all of its oil has been recovered, the pre-treated water is fed into an MBR before being discharged. The resulting effluent water is very clean and even exceeds the German Waste Water Directive.

MBR stands for membrane bioreactor and describes the combination of a bioreactor with a microfilter as part of a wastewater treatment unit. The water is first pumped into the bioreactor, where organic matter is degraded with the help of microorganisms. In the following ultrafiltration process any debris is removed, thus further increasing the purity of the discharge water.

Exhaust Gas Collection: Any hydrocarbon gases that might form during the incubation process pass through a gas condenser and retained via an activated charcoal unit.


After all oil waste has been processed, the Zaopin SOR system can be disassembled in a few easy steps. The system is then ready for the next oil recovery job.

Slop Oil Recovery Services

We conduct oil recovery services worldwide using our own SOR equipment. Whether you want to get rid of tank bottom sludge, slop oil, or other secondary oils, our system's near 100% recovery rate makes your project very cost-efficient. In fact, thanks to the high market value of the reclaimed hydrocarbons, you actually make a good profit.

Slop Oil Recovery Services