WCSEE Flocell XFM a game-changer in Tertiary Solids and P-removal for wastewater

Regulations associated with asset management plan 2025-2030 (AMP8) continues to push towards the target of 0.25 milligrams of phosphorus per litre of effluent across an increasing number of wastewater treatment plants (WwTP).

This shift has now placed growing pressure on smaller WwTPs, which present unique challenges in meeting performance targets while keeping costs down and return on investment justified. 

Additionally, with a changing climate, each water company has its own net zero and water use reduction targets which is fuelling the need to trial, hire, and buy equipment which is offering new and innovative solutions to age old problems.

The Flocell XFM Filtration System effectively helps WwTPs struggling with overloading due to changing phosphorus consent levels, population growth and climate challenges.  

Read below to discover how the Flocell XFM offers water managers a game changing product without the same compromises as traditional filtration systems

How is the Flocell XFM Filtration System revolutionising tertiary solids and phosphorus removal in wastewater treatment? 

Originally developed for application in the high value koi carp pond filtration, the Flocell had been a proven technology in the aquatic sector for over two decades - before expanding into the wastewater treatment market. 

Flocell is a game changer because it gets phosphorus levels down to consistently low levels with less energy, water use, and complexity compared to other technologies currently on the market. Like all filters the phosphate has to be presented as a particulate, this is generally achieved using ferric, or a combination of organic coagulants such as Cofloc and ferric.

For an in-depth case study, read about our trial with United Utilities which helped a WwTP achieve phosphorus removal levels as low as 0.04 mg/l, leading to a contract win.

Headline benefits include:

• 94% less energy and over 99% less water use compared to conventional filtration systems
• No backwashing needed
• Captures particles as small as 1µm and over 50% of particles larger than 5µm 
• 20-year life span on average for the XFM housing and media
• Hire options can be turned around in days
• Capital projects from the initial conversation can deliver lead times no longer than 8 weeks, with the option to hire whilst the units are built to meet a specific asset standard
• Quick operating training and no special skills needed

How does the Flocell XFM system compare to other filtration systems? 

Traditional units force trade-offs such as:

• Paying more to install and maintain.
• Running frequent backwash cycles.
• Increasing the load on main treatment stages.
• Buying costly parts for replacement or chemicals to clean.
• Skilled staff needed to operate and clean frequently. 

Traditional filtration systems and how they compare to the Flocell XFM: 

Pile cloth filters are more expensive to purchase, install, and maintain and are labour-intensive. When the backwash tank of a pile cloth filter is full, the system stops working. Pile cloth filters also struggle with larger solids and can block quickly.

The Flocell XFM does not backwash, instead it uses air scouring to release the solids from the filter and then the filter is ‘drained’, a process that takes about thirty minutes once a week and needs no more water than that contained in the filter, almost eliminating any water being returned to the head works.

The Flocell XFM will also hold approximatly 20-30x more solids than a pile cloth filter. Flocell XFM’s have been used as pre-treatment before cloth filters and also to treat the backwash water where cloth filters have already been installed and are causing hydraulic issues. 

Screen and drum filters involve costly maintenance and continuous backwashing, which creates hydraulic loss prone to quick blockages with larger loads, breaking up particles during filtration.

By supplementing the screen and drum filter process, the Flocell XFM system can be used to clean backwash water or reduce pressure on the unit beforehand, much like the pile cloth filter.

Additionally, the effectiveness of screen and drum filters is determined by their mesh size, typically capturing particles no smaller than 20µm. The Flocell XFM captures particles as small as 1micron (µm) and over 50% of particles larger than 5µm. 

Multimedia depth filters are costly to purchase and install, requiring significant civil works and a larger footprint. It also necessitates the delivery and use of COSHH-regulated chemicals, for cleaning  

Additionally, multimedia depth filters require a separate backwash tank, using 6% of its process water for cleaning, which disrupts the hydraulic balance of the WwTP. 

Basic sand filters are an older WwTP technology that are initially cheaper to purchase. However, they require a powerful pump to operate increasing operating costs and the large backwash volumes dilute the sludge. These filters are also prone to quick blockages when handling larger loads and require frequent media changes. As a result, downtime is more frequent, leading to process inefficiencies and higher costs. 

What makes the filter cleaning cycle of Flocell unique? 

 The Flocell XFM modular filtration system uses Air Clean technology to clean the filters, replacing the traditional backwash cycle. Low-energy blowers agitate the media pack, effectively removing trapped solids during a brief cleaning cycle. This air-based method reduces energy consumption and means that the filter is ‘drained’ and not backwashed, minimising water loss. 

With no moving parts or hydraulic pressure in the filter, the Flocell XFM further reduces energy consumption and requires no process water to operate.

More importantly, the filter cleaning cycle has a high solids content of 0.8 – 1.2% dry solids, allowing the throughput to be directed straight to onsite sludge storage or returned to the head of the works for co-settlement with incoming effluent. All without significantly increasing the hydraulic load.  

Lastly, no chemical cleaning is needed, as the filter system is not affected by polymers or chemicals, and it requires no parts, consumables, or lubricants. 

What is the unique advantage of the multi pass (bio-dialysis) mode of the Flocell XFM compared to traditional filters? 

If deployed, bio-dialysis mode offers benefits including: 

• Increases the capacity to remove solids and increased sludge thickness
• Flexible implementation between process stages
• High solids holding capacity
• Keeps surface sludge down
• Does not disturb the sludge blanket
• Still operates as per a final settlement tank
• Volume of effluent requiring treatment is significantly reduced
• Provides a buffer volume whilst backwash is undertaken

What are the benefits of using open cell media? 

The open-cell media on the Flocell XFM is designed to efficiently reduce tertiary solids and soft, difficult-to-manage flocs, retaining particulates without increasing pressure within the filter or reducing flow. Benefits include: 

• Open cell media does not create hydraulic loss
• Designed to consistently trap and remove particles down to 1µm
• Remove 50% of particles larger than 5µm 
• Media only needs cleaning with system water
• Saves money on installation and operating cost ​
• 100% virgin HDPE and no plastic shedding issues– compliance tested

How can the Flocell XFM system assist operational teams when under pressure for on-site visits and tight lead times? 

More traditional, long‐established providers of p-removal technologies are regularly quoting lead times exceeding 36 months.

Manufactured in the UK with a 20-year life span on average, the WCS Flocell XFM can be shipped within eight weeks and a hire unit can be on site within days which can be useful for trialling the technology as well as ensuring permit consents are never breached and no shutdowns are required.

With the Flocell XFM installed, operations teams only need to go to a WwTP every one or two weeks, for less than 30 minutes on average, freeing time to do other things.  

It sits perfectly between being a fully automated system, which tends to be very expensive, and a traditional system with moving parts which takes a lot of management time and parts replacement on site.  

How easy is it to deploy and install the Flocell XFM? 

The Flocell XFM promotes standardisation across WwTPs. It’s scalable, modular, container design provides exceptional flexibility, especially in space-constrained environments or when rapid deployment is required, with no need for civil works as no concrete base is required on a flat surface.  

With a quick commissioning time of just one hour and thirty minutes onsite training, it is the perfect solution for time-sensitive or temporary setups. 

• Ease of integration with critical systems​
• No requirement for specialist training or qualifications. 
• Shock loading capacity​
• Ideal for maintaining compliance during system downtime
• Modular container design means it can be easily moved between sites
• Scalable and additional units for extra capacity can be installed easily. 

What are the benefits of using mobile lab testing when trialling the Flocell XFM? 

Customers have the peace of mind to know what size Flocell XFM is needed before hire, trial, or purchase. Mobile lab testing and particle size analysis of on-site effluent samples enables us to identify the most efficient wastewater treatment equipment needed. 

Trials always start with a single unit as a ‘starter for ten’ and WwTP operators go from there. Mobile lab testing benefits include: 

• Up to fifteen user-defined size cohorts between 2µm - 125µm​
• Real time analysis up to four samples per hour ​
• Critical for solution-matching​
• TSS analysis​

What are the plans for expanding Flocell XFM as water companies goes through AMP8? 

WCSEE is looking to make bigger Flocell XFM units and developing them to include all the ancillary equipment as standard, so it doesn’t matter what pre-existing infrastructure a WwTP has.  

The ambition is also to develop the Flocell XFM so it can be used in tandem with the WCSEE Hybrid biological treatment as a final polishing step for effluent. The advantage would be that WCSEE would be able to offer a complete solution for CSOs or stormwater events. The next stage is the find collaborations with water companies to start trialling this ‘all-in-one' set up.