Backwash Filter for a Small-Scale Electrocoagulation Trial
We recently had the pleasure of working with a client in New Zealand who is truly passionate about environmental protection. They are testing a pilot electrocoagulation (EC) unit on a small communal wastewater treatment plant – and we were brought in to supply the critical filtration step.
Here’s how the conversation unfolded – and where we ended up.
The client’s goal – clear and ambitious
Their EC reaction chamber removes sediments and organic matter from treated wastewater. The solids are mainly inorganic flocs from the coagulation process. They needed a backwash filter that could:
- Remove solids down to <25 microns (ideally)
- Handle a small trial flow of ~1 m³/h
- Tolerate a solid content of about 3%
- Discharge the concentrate to a screw press (dewatering)
- Be made of SS316 for durability
Our initial proposal – and their thoughtful pushback
We first suggested our Model JX-XF-300 Automatic Backwash Filter, equipped with a 5‑layer sintered mesh element that can achieve precision. We felt confident this would meet their needs.
But the client came back with a very valid concern: their actual TSS after the sedimentation tank was only 20–50 mg/L, and they worried that organics and polymer residues might cause rapid pressure build‑up. That would trigger frequent backwashing – disrupting their trial. They felt that a 25‑micron filter might be safer for continuous operation, and they asked if they could order an extra 5‑micron cartridge to swap in later, on their own, if they wanted to test finer filtration.
Open dialogue – the key to a better solution
Instead of a quick “yes/no”, we encouraged a deeper technical exchange. The customer raised several excellent questions about backwash water, feed pump, and overall process integration. We welcomed every single one – because those discussions helped us truly understand their system constraints and operational rhythm.
We shared our experience with similar trials, explained how backwash frequency is affected by loading. It wasn't just about selling a filter; it was about making sure the filter would work with their EC unit and screw press seamlessly.
The final decision – a tailored package
After a few weeks of careful internal review, the client chose our SS316‑400 Automatic Backwash Filter – a slightly larger model but perfectly sized for their 800 L/h flow rate. What made it special? They ordered it with both a 25‑micron and a 5‑micron filter element.
That way, they can start with 25 microns for stable, low‑interruption operation. When they feel ready, they can swap in the 5‑micron element to test higher purity – without any major modifications. This gives them flexibility and peace of mind.
Where we are now
The unit has been manufactured, tested, and shipped. We're happy to report that the client has already received the equipment in good condition. We’ve also provided detailed drawings and measurement photos for their reference.
We’re genuinely excited to see how their trial progresses. The New Zealand team has been a pleasure to work with – thoughtful, thorough, and genuinely committed to finding a sustainable solution. We’ll be following up to offer any support they might need during startup.
Final thought
This project reminded us that the best solutions don't come from a one‑size‑fits‑all catalogue. They come from listening, asking the right questions, and adapting to real‑world conditions. We’re proud to be part of this innovative trial – and we look forward to more collaborations that push the boundaries of water treatment.