FIX800 Multi-Gas Detector (O2/H2S/EX) and CO Detector — Sewage Sludge Resource Recovery Facility (Pohang, Gyeongsangbuk-do)

Following our previous post, we're sharing another Pohang installation case.

Looking back at some of our more demanding recent projects, this Pohang sewage sludge resource-recovery facility was one of them — though we never expected it to come back around in such a meaningful way. Last time we didn't have enough photos, so the write-up ran long; this time we'll get straight to the point.
Facility: Pohang sewage sludge resource-recovery facility
Installation points & equipment: Sludge intake area — FIX800 (O₂/H₂S/EX) 1 set + outdoor display board; Dried sludge storage tank — FIX800 (CO) + advanced pre-treatment unit + free-standing display board
Schedule: 2 teams of 2, completed in one day
First, let's look at what a sewage sludge resource-recovery facility actually is.

Photo credit: Seoul Metropolitan Landfill Site Management Corporation. Sewage sludge, put simply, is the combined food/kitchen wastewater that drains from household sinks. A facility that processes this collected sludge through several stages to recover it as a resource is called a resource-recovery facility — the same general concept as the livestock manure treatment facility we covered in an earlier post, where we went into the chemistry in more detail.

This project covered the two points shown above.
Sludge intake area: Once the intake process finishes, the shutter is lowered and the space becomes fully enclosed — filled with odorous, potentially explosive gases. Gas detectors were installed here for the safety of workers inside.

2. Dried material storage tank: a warehouse where heat-treated material from the intake area is stored. Picture one giant tank beneath a green urethane floor. Combustible gases such as methane, generated by the dried sludge just before resource recovery, can ignite from even a small spark, so a CO detector — the primary combustion gas indicator — was installed to prepare for that fire risk.

Because installation points and power-supply methods had already been worked out over several prior meetings, the on-site work itself went smoothly.

After completing the required safety training, our team briefed the site manager on the installation plan and sequence. Working in two teams, each group tackled one installation point. Both proceeded simultaneously, but we'll walk through them one at a time — starting with the sludge intake area.
Sludge intake area — multi-gas detector installation

1. Drilled through the concrete wall and mounted the display board first.
2. Power is drawn from the ventilation-fan outlet behind the wall — a single outlet was converted to a duplex outlet, leaving a spare.
3. Installed the detector and cut the cable to length.

4. Terminated the cable ends to match the cut length.
5. Neatly routed the cable using saddles so as not to interfere with existing fixtures.
6. Finally, connected the display board to the FIX800 — done. Simple, right?

7. The detector powers on and shows normal readings.
8. The outdoor display board also shows a normal (green) status.
9. We injected test gas to run the alarm test — completed cleanly.
2. Dried sludge storage tank — CO detector installation

This point required a free-standing stainless enclosure and pre-treatment unit, so anchor work came first. Drilled to match the anchor bolt length, cleaned the drilled area and surrounding dust, and re-waterproofed around the drilled section to protect the existing waterproof coating.

4. Installed the anchors and leveled the enclosure.
5. Ran piping so the GAS IN/OUT hoses could connect to the blower's front (positive pressure) and rear (negative pressure) ports — these ports had already been welded per prior agreement at the planning meeting.
6. Connected the pre-laid 220V power line and 4–20mA signal line. Unfortunately the electrical team's schedule didn't align, so power wasn't immediately available.

7. Connected the durable PTFE hose to the completed piping.
8. Walked the site manager through product operation and usage.
9. Finished product — ta-da. We tidied the conduit and gas line with cable ties afterward, but unfortunately didn't get a photo of that final state. Wondering how we ran the commissioning test without power yet connected?

The answer: a portable backup battery. This project involved two somewhat different installation jobs at the same site, carried out at the same time. Because we'd already worked out all the details through a site survey and multiple prior meetings, the actual on-site work wrapped up quickly and simply — a good reminder of how important thorough preparation is. We think today's photos speak for themselves, so we'll close here. If you need a gas detector, feel free to reach out.

Frequently Asked Questions (FAQ)

Q1. Why are gas detectors needed at both the sludge intake area and the dried sludge storage tank?

The sludge intake area becomes a sealed, enclosed space once the shutter closes after intake, with odorous and potentially explosive gases present — requiring detection for worker safety. The dried sludge storage tank can generate combustible gases like methane from the drying material, so a CO detector monitors for fire risk.

Q2. What's the difference between the two FIX800 configurations used here?

The sludge intake area used a FIX800 configured for O₂/H₂S/EX (combustible gas) with an outdoor display board, while the dried sludge storage tank used a FIX800 configured for CO with an advanced pre-treatment unit and a free-standing display board — each tailored to the specific gas risks of that location.

Q3. How long did this two-location installation take?

Two teams of two worked simultaneously, completing both installation points in a single day, largely because installation points and power-supply plans had already been finalized during prior site surveys and meetings.

Q4. What is a pre-treatment (sampling conditioning) unit used for?

It conditions the sampled gas before it reaches the sensor, filtering out moisture, particulates, or other interference so the detector can measure the target gas accurately in demanding environments like a sludge storage facility.

Q5. How was the system tested before permanent power was connected?

A portable backup battery was used to power the unit temporarily, allowing the team to complete the commissioning and alarm test on the same day, even though the permanent electrical connection was scheduled separately.