SINOKLE Dual-Media Filter: Gradient Purification and Filtration for Industrial Wastewater

In industrial water treatment applications such as oilfield oily wastewater, refinery wastewater and metallurgical/chemical wastewater, advanced filtration is a critical step for meeting discharge standards and enabling water reuse. Conventional single-media filters (for example, quartz sand filters) have long suffered from three notable problems:

• Limited filtration precision - most can only retain particles larger than 10 um, removing suspended solids incompletely and leaving downstream treatment under a consistently high load;

• The single media bed is prone to compaction and clogging, backwashing is ineffective and frequent shutdowns for maintenance are required;

• Poor adaptability - it is difficult to satisfy high capacity and high precision at the same time.

Built around gradient media combinations and high-efficiency air-water backwashing, the SINOKLE dual-media filter integrates structural design with automation technology. It not only overcomes the precision and efficiency bottlenecks of conventional filtration but also greatly optimises O&M costs - a professional and practical technical solution for advanced industrial wastewater treatment.

1. Technical principle

The core innovation of the SINOKLE dual-media filter lies in the gradient layering of dissimilar filter media - the key to achieving high precision, high loading and low clogging. The filter uses a combination of anthracite and emery. Because of the density difference between the two media (anthracite about 1.4 g/cm3, emery about 3.6 g/cm3), a layered structure forms naturally during operation: light on top, heavy below; coarse on top, fine below. The upper anthracite layer has relatively large particles (typically 1.2-2.0 mm) and is responsible for retaining large suspended solids and floating oil in the wastewater, acting as a coarse screening buffer. The lower emery layer has smaller particles (typically 0.5-1.0 mm) and, thanks to its higher hardness and density, precisely retains particles and colloidal contaminants above 2 um, achieving fine filtration.

This gradient filtration mode avoids the clogging problems of a single fine-media bed. By retaining contaminants in stages - coarse first, fine afterwards - it maximises filtration efficiency and the dirt-holding capacity of the media bed. In effect, it creates a purification barrier for the wastewater that runs from coarse to fine, so particles of different sizes are captured by a precisely matched media layer.

2. Technical advantages

Based on the product parameters and characteristics of the SINOKLE dual-media filter, its technical advantages are high precision, high adaptability and easy O&M. A comparison with conventional single-media filters highlights how innovative it is:

Specifically, the technical advantages can be broken down into four points:

1. High precision and high removal rate: meeting stringent water quality requirements

With its dual-media gradient structure, the SINOKLE dual-media filter stably retains particulate contaminants above 2 um with a suspended solids removal rate of 98%. Even for industrial wastewater with influent suspended solids of no more than 50 mg/L, filtered suspended solids can be reduced to below 5 mg/L. It also has a notable synergistic oil-removal effect on oily wastewater, with oil content in filtered water of no more than 5 mg/L - fully meeting stringent water quality standards for oilfield reinjection and industrial water reuse.

2. Efficient backwashing: thorough media regeneration, avoiding compaction and clogging

A combined air-scour plus water-wash backwash mode is used: the air disturbance breaks up the compacted media bed while the water flow carries retained contaminants fully out. This avoids both the incomplete cleaning of water-only washing and the media loss risk of air-only scouring. The media regeneration rate exceeds 95%, greatly extending the media replacement interval.

3. Flexible adaptation: covering multiple application requirements

Capacity per unit ranges from 5 to 150 m3/h, with a design pressure of 0.6-2.0 MPa and a design temperature of up to 80 C. Units can be combined in series or parallel to suit different treatment scales, from small and medium oilfield produced water to large refinery wastewater. Filtration resistance is no more than 0.12 MPa, and energy consumption is far lower than that of precision membrane filtration equipment.

4. Automation and easy O&M: lower labour and time costs

It supports fully automatic operation and remote control with no on-site dedicated staffing. Operating procedures are simplified and backwashing can be triggered automatically (based on filtration resistance or operating time); maintenance only requires periodic checks of media loss. Compared with the frequent shutdowns and manual media cleaning of conventional filters, average monthly O&M time is reduced by more than 60%.

3. Application scenarios

Thanks to its gradient purification characteristics, the SINOKLE dual-media filter closely matches the advanced industrial wastewater treatment needs of many industries, as follows:

1. Oilfield oily wastewater treatment: used as the fine filtration step before produced water reinjection, the filtered water meets formation reinjection requirements for low suspended solids and low oil content, effectively preventing formation plugging.

2. Fine filtration of refinery wastewater: applied to the advanced treatment of desalting effluent and circulating water blowdown, providing stable water quality for subsequent reuse or compliant discharge.

3. Metallurgical/chemical wastewater treatment: effectively retains heavy metal precipitates and chemical colloidal particles, reducing the load on downstream biological or membrane treatment and extending the service life of core equipment.

4. Textile wastewater reuse filtration: removes dye particles and fibrous suspended solids, enabling recycling of reclaimed water.

Take an oilfield produced water project: influent oil content of no more than 50 mg/L and suspended solids of no more than 50 mg/L were reduced after treatment by the SINOKLE dual-media filter to effluent oil content of no more than 3 mg/L and suspended solids of no more than 4 mg/L, meeting oilfield reinjection standards. The unit has a capacity of 50 m3/h and required only one media top-up in six months of operation, cutting O&M costs by 40% compared with conventional quartz sand filters.

4. Technical value

Through high-precision filtration, the SINOKLE dual-media filter achieves advanced purification of industrial wastewater. It not only helps enterprises comply with strict regulations such as the Emission Standard of Pollutants for the Petroleum Refining Industry but also promotes wastewater reuse and reduces freshwater consumption. Compared with membrane filtration equipment, investment cost is more than 50% lower and operating energy consumption 30% lower, while O&M costs of downstream treatment units are significantly reduced.

The filter's automation and high-efficiency backwash design free industrial water treatment from dependence on heavy manual input, matching the intelligent transformation needs of industrial enterprises. It overcomes the precision limits of conventional filtration while meeting the demands of high-load operation and easy O&M in industrial settings - the preferred solution for advanced industrial wastewater treatment, combining professionalism, practicality and cost-effectiveness.