KDS technology requires no wash water
As environmental regulations tighten and sustainability becomes a global imperative, effective sludge management is emerging as one of the textile and fashion industry’s most urgent challenges—particularly in the Asia-Pacific region. At the heart of this issue is textile sludge, a hazardous byproduct of manufacturing that demands efficient, affordable treatment solutions, especially for small and medium-sized enterprises (SMEs).
In this exclusive interview with Fibre2Fashion, Mike Bambridge, Managing Director of CST Wastewater Solutions, sheds light on KDS liquid-solid separation technology—a compact, low-maintenance, and highly efficient system designed to transform how SMEs handle sludge. With decades of expertise in wastewater treatment and a clear commitment to sustainable innovation, Bambridge explains how KDS technology addresses the pressing environmental risks of sludge, cuts down disposal costs, and integrates seamlessly with existing DAF systems to support the industry’s eco-friendly transition.
Why is sludge management such a critical issue for sustainability in the textile and fashion industry today?
A substantial and enduring manufacturing sustainability issue such industries must face is textile sludge, which is an unavoidable byproduct of textile manufacturing processes. Sludge treatment and disposal must be treated responsibly to achieve the textile and fashion industry’s objective of sustainability and eco-friendliness.
The issue is growing, because as textile industries scale up to meet global demands, the volume of textile sludge has increased significantly. This waste material poses a significant challenge for disposal because of its hazardous nature and environmental impact.
What are the main environmental and health risks associated with improper disposal of textile sludge?
Textile sludge is the semi-solid residue generated from wastewater treatment processes applied, particularly, in the primary stages of textile manufacturing. This sticky and hazardous material separated from process water can vary widely depending on the specific processes and chemicals used. Generally, sludge is expensive to handle, costly to transport and dear to dispose of using increasingly limited and costly landfill facilities, which must be properly engineered to prevent leakage to groundwater.
Hazardous components of textile sludge can often contain toxic substances such as chromium, cadmium, lead, and heavy metals which can contaminate soil and water sources, leading to long-term ecological damage.
Improper disposal of textile sludge more generally can lead to harmful chemicals leaching into the soil and groundwater, adversely affecting agricultural productivity and posing health risks to communities relying on these water sources.
Also, decomposition of organic matter in textile sludge can produce potent greenhouse gases, so, when not managed properly, sludge disposal can contribute to climate change.
What are the biggest challenges faced by small and medium-sized textile manufacturers when it comes to wastewater treatment and sludge disposal?
The biggest challenges are treatment and disposal. Textile manufacturing processes are always going to produce sludge as a byproduct, but the methods in which this sludge is treated can vary, and this is where SMEs can stand out from their competitors by using environmentally-harmonious technologies that also benefit the bottom line by saving in transport and disposal costs.
In your experience, what are the biggest misconceptions SMEs have about sludge management and treatment technologies?
There can be a misconception that ‘bigger is better’ when it comes to sludge dewatering systems. And with bigger systems costing more money upfront, this can be a barrier to SMEs investing in sludge treatment technologies that can help them reduce handling costs and improve their environmental credentials.
Could you briefly explain the core concept of KDS liquid-solid separation technology and how it differs from traditional sludge treatment methods?
The compact KDS multi-disc roller separator features a unique self-cleaning dewatering and conveying system with oval plate separation and transfer structure that prevents clogging and permits automatic continuous operation that handles oily and fibrous material with ease.
KDS – which requires no washwater, while capturing 90-99 per cent of solids – is engineered to overcome the limitations of technologies such as screw presses, belt presses and centrifuges currently used.
The largest energy-saving KDS unit can handle about 100kg DS (dry solids) an hour at 98 per cent solids capture, to produce this more hygienic and more compact output that is easier and cheaper to handle and transport.
How does KDS technology cater to the needs of small and medium-sized enterprises (SMEs) in the textile and fashion industry?
Efficient sludge dewatering can reduce the volume of sticky sludge produced by typical DAF (Dissolved Air Flotation) installations by 70-90 per cent, making it lighter, drier, safer to handle, transport and dispose of or recycle.
But obstacles to wider adaptation of such technology by SMEs may include costly large dewatering systems, when SMEs typically need more compact and profitable ways to make sludge dryer, lighter, easier to handle, and safer to dispose of.
Oversized systems often have built-in high operating costs to achieve results, including costly use of polymer, electricity, and wash water. They also may require the presence of skilled engineering staff to optimise their performance, dedicated skills that SMEs often do not have and cannot afford.
A science-based approach looks at the particular challenges first. So, because different types of textile processes face different challenges, environmentally aware and quality-focused wastewater treatment professionals do not ever propose that just one solution is the total answer to all water quality issues.
There are many excellent technologies out there suitable for different applications, of which KDS is an outstanding example in the sludge dewatering category for SMEs.
What are the key environmental benefits of using KDS technology for managing textile sludge, particularly in Southeast Asia’s fast-growing fashion sector?
DAF systems are widely used in the textile industry already. They couple readily with KDS Multidisc Roller technology systems, which require no wash water, while capturing 90-97 per cent of solids. Such systems are engineered for simple, reliable operation, with their self-cleaning multidisc functionality helping to overcome the limitations and maintenance needs of technologies such as screw presses, belt presses and centrifuges.
A substantial and enduring manufacturing sustainability issue textile and fashion industries must face is textile sludge, which is an unavoidable byproduct of textile manufacturing processes. Sludge treatment and disposal must be treated responsibly to achieve the textile and fashion industry’s objective of sustainability and eco-friendliness.
Could you elaborate on the science behind the self-cleaning multidisc mechanism and how it enhances operational efficiency?
When sludge enters the KDS system, it is put through a series of rotating oval plates. The plates are aligned in such a way that liquid (filtrate) is squeezed out and falls to a separate area below. Solid matter, now removed of much of its liquid content, continues along the conveyor until it reaches the end of the oval plates section. Here it continues down an angled chute and into a receptacle ready to take away for disposal. Because the oval plates rotate right up to the end of the conveyor section, no solid material gets stuck. The oval plates keep pushing down on the solid material to keep the filtering zone clean.
Variations in sludge properties are accommodated by adjusting the rotational speed of the oval-plate units and the pressure of the pressure plate. Complex adjustments are not required.
For example, if the priority is treatment capacity, the operator can increase the rotational speed of the oval-plates and reduce the pressure of the plate to improve it. On the contrary, if the desired result is high dryness of discharge cake, the operator can reduce the water content by slowing down the oval-plate units’ rotation and increasing the pressure of the plate.
What kind of reductions in sludge volume and disposal costs have users typically experienced with KDS systems?
The KDS was used in the US, where it cut sludge volumes and waste transport and disposal costs to less than a seventh of previous levels.
The US in-service performance assessment of KDS sludge dewatering technology – conducted over 250 days to demonstrate accuracy and reliability – involved a mixed food waste disposal challenge involving oily and starchy wastewater treatment issues of a type typical of SME food and beverage processing operations and of commercial kitchen waste, cleaning and grease trap processes.
The technology assessment – which is equally applicable to KDS operations in Australasia and SE Asia – also produced waste that is safer for wastewater maintenance and cleaning staff by radically reducing the amount of sticky, hazardous waste they typically have to handle.
The in-service trial of KDS technology – which cuts sludge volume before dewatering from 403 tons to 53.52 tons afterwards – disproves the common misconception that energy-efficient and environmentally harmonious sludge separation wastewater treatment is mainly for the largest applications.
How does your system integrate with existing DAF installations in textile manufacturing plants?
DAF systems are often used as the primary sludge handling process in textile manufacturing plants, but their output can often involve wet, sticky sludge. In one example, a KDS employed after DAF processing in a textile process has produced a solids capture rate of 95.7 per cent, with a sludge cake dryness of 22.6 per cent, meaning a high proportion of the heavy and sticky water content has been removed. The textile example was achieved with dissolved solids content of 6kg an hour, and hydraulic flow of 0.2m3 an hour.
From an economic standpoint, how quickly can SMEs expect a return on investment from installing a KDS system?
The ROI would vary depending on a number of factors, including sludge volumes, how the KDS is set up (rotation speed and pressure of the pressure plate), how sticky the sludge is, and how often the KDS is in operation. But using some of the examples cited here, SMEs can expect immediate benefits, and a good ROI when using KDS for sludge dewatering.
Are there any particular textile manufacturing processes or conditions where KDS technology may not be as effective?
For larger operations, there will be larger equipment that is better suited to these applications. KDS is particularly effective for SMEs, or for large operations where sludge treatment is only required at levels up to 100kg DS (dry solids) per hour. For operations requiring greater levels than this, there are a range of other technologies available.
How does KDS technology address hazardous substances in sludge, such as heavy metals and toxic dyes?
KDS systems separate out the hazardous substances, so that they do no end up in water tables, where they can create environmental hazards.
What innovations are KDS working on to further improve sludge dewatering or broaden applications beyond textiles?
The KDS system is broadly applicable to a wide range of industries, including:
- Municipal wastewater applications, including sewage treatment
- Food and beverage wastewater applications, including pork, poultry, seafood, fruit, vegetables, commercial food waste, abattoirs, feed lots
- Industrial wastewater applications, including anaerobic fermentation tanks, grease traps, chemical recycling, and plastic recycling.
