In most of the wastewater treatment plants, Static Screen is used in the pre-treatment stage to screen fibrous and non-greasy solids. Static screen operates by gravity without the need of actuating equipment. Sieve screen with slot sizes ranging from 0.15mm to 2.0mm is offered depending of the suitability of industries. This screen type is convenient and does not require regular maintenance as it has no moving parts and is able to self-clean. This screen type is used especially in the treatment plants of such industries as chicken slaughtering, pulp and paper, food processing, alcohol production, etc.
Rotary Drum Screen
Compared to Static Screens, Rotary Drum Screens can cope with a larger flowrate in a smaller footprint. The solids from the wastewater will be separated by a wedge wired rotating drum from the liquid and then washed out by a set of internal and external pipes with nozzles. Rotary Drum Screen uses high-pressure washing to eliminate blocking of the screen and ensures the screen surface is solid-free to be ready for another cycle. The separated liquid is discharged from the bottom of the drum to the next point of treatment.
Dissolved Air Floatation (DAF)
Dissolved Air Floatation (DAF) is an established physical/chemical technology and proven for its diversity on treating different industrial and municipal wastewaters. DAF system is designed to remove suspended solids (TSS), oils and greases (O&G) and other pollutants from wastewater. The process of DAF is based on the concept of dissolved air-in-water solution which is produced by feeding air to the incoming wastewater forming tiny bubbles that attach to the contaminants causing them to float. The floating sludge is then scrapped of the surface of the water into the sludge compartment.
Inclined Plate Clarifier (IPC)
Inclined Plate Clarifier (IPC) also known as lamella clarifier is a clarification tank which is fitted with inclined plate pack to promote sedimentation of solids. This design makes IPC stand out compared to the common clarifier as it is designed to allow floating suspended solids to collide with the plates and fall to the bottom of the clarifier whereas the water is led back to the top. Unlike the common clarifier, separation of solids in IPC is independent of the liquid volume but the available settling surface area. Therefore, it is most efficient to employ IPC for plant upgrades due to its large settling surface area and small footprint.
Moving Bed Biofilm Reactor (MBBR)
Moving Bed Biofilm Reactor (MBBR) Technology is the cutting edge of biological treatment in Wastewater Treatment Plant (WWTP) The MBBR Technology is currently the most advanced solution for COD/BOD Degradation, Nitrification and Denitrification Processes. The technology in MBBR system which employs BioChip as the biological carrier has proven to deliver consistent and outstanding performances in many application. IWE provides services for the design of MBBR systems as below.
BioChip carrier plays a very strong role in MBBR Technology particularly to provide higher removal rates and more reliable process stability. These two key points can be well achieved by our patented BioChip which is able to provide removal rates up to 10 times higher than any other conventional bio carriers by other competitive solutions.
Know-how and services:
- MBBR plant design
- Design of process air supply
- Design of carrier retention screens
- Tank design
- Process engineering
Activated Sludge Process (ASP)
Activated Sludge Process (ASP) is a conventional treatment process which is widely used in industrial wastewater treatment. The principle of ASP consists of three main components such as aeration tank, clarifier and return activated sludge (RAS). Activated sludge refers to the suspended aerobic sludge consisting active bacteria and this aerobic biomass acts to reduce the BOD and ammonia concentrations in the aeration tank by consuming biodegradable organic substances in the wastewater. Aeration and mixing in the aeration tank can be provided by providing air into the tank using diffused aeration through blowers or surface aerators. The biomass from the aeration tank flows to the clarifier where the thickened biomass is separated from the clarified water. Clarified water overflows to the next tank while part of the separated biomass is recycled back to the aeration tank as RAS. The purpose of RAS is to re-seed the new wastewater entering the aeration tank ensuring desired MLSS concentration. This conventional treatment process has been the very well established and guaranteed to provide efficient wastewater treatment for various industries.
Sequential Batch Reactor (SBR)
Sequential Batch Reactors (SBR) is a special form of activated sludge treatment which is able to achieve equalization, aeration, and clarification in single reactor basin. This process treats the wastewater in batch system and each batch is operated in a timed sequence through a series of treatment stages. The SBR system operates in cycles which consist of 5 basic phases i.e. Fill, Aerate, Settle, Decant and Idle. During ‘Fill’ phase, the basin receives influent wastewater and aeration starts as soon as the tank has been filled. The ‘Aerate’ phase requires mechanical mixing and aeration which allows biochemical reactions to take place. Then, during ‘Settle’ stage, the aeration would stop and the activated sludge is allowed to settle under quiescent conditions at the bottom of the tank leaving clear supernatant at the top. Floating decanters will be used to ‘Decant’ the clear supernatant. ‘Idle’ signifies the standby period for the next cycle to commence and is normally set at a very short time. The adequate time provided for each phases shall be controlled using PLC.
Upflow Anaerobic Sludge Blanket (UASB)
Upflow Anaerobic Sludge Blanket (UASB) is an anaerobic process designed to achieve high removal of organic pollutants (1~10kg COD/m3/d). The wastewater enters the reactor tank from the bottom and flows upwards. This influent passes a dense anaerobic granular biomass bed where biological conversion process takes place. During biological conversion, the bacteria living in the sludge breaks down the organic matters by anaerobic digestion, thus, transforming Chemical Oxygen Demand (COD) load in the wastewater into biogas. Gas Liquid Solid (GLS) Separator installed above the sludge blanket separates the mixture by allowing liquid and gas to leave the UASB reactor meanwhile facilitates the sludge return back into the reactor.
Expanded Granular Sludge Bed (ESGB)
Expanded Granular Sludge Bed (EGSB) reactor is a variant from the UASB process and utilizes the same operating principles. The distinguishing feature is that EGSB has a more rapid upflow velocity passing through the sludge bed. The increase in flux allows fluidization of the granular sludge bed and improves the contact between wastewater and the biomass. Besides increasing the upflow velocity, effluent recirculation is also used to enhance the substrate - biofilm contact. With the improved process, EGSB is proven to be able to treat high-strength organic wastewater (25~30kg COD/m3/d). Biogas is also produced in this system and collected at the top of the reactor using Gas Liquid Solid (GLS) Separator.
Belt Press is great for dewatering applications in wastewater treatment plants due to its compact design and reliable operating method with minimum operating complexity. Wastewater from the sludge tank is first treated with polymer to allow formation of stronger flocs and then fed into the belt press. The thickened sludge is conveyed along the belt and pressed between two belts to drain out water content from the sludge. The dry sludge is collected in a bin and the filtrated water is transferred back for re-treatment. Belt press offers much lower power consumption and is suitable to be used for start-up or upgrading plant.
Filter Press is a pressure filter which treats concentrated slurry and recovers clear filtrate by using pressure filtration. Slurry is pumped into the filter press and dewatered under pressure which leaves the cake with water contents of lower than 75%. Cake is then discharged by scrapping the cake off the cloth. Filter press operates by batch either by manual or automatic and has simple mechanism which allows easy maintenance and inspection.
Screw Press can be applied in a wide variety of dewatering applications. The screw press consist of a cylindrical wedge wire basket which allows filtrate to be drained out and the solids in the basket are conveyed gently by the slow moving rotating screw upwards to the discharge end of the screw press. This dewatering press operates continuously and can achieve high efficient dewatering with low maintenance requirement. Screw press also has low footprint due to its compact design and flexible to work with in a wide range of industries.