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Odor control for complex sludge processing emissions

Control complex sludge odors with electric treatment proven to remove key sulfur compounds below detection limit.
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99.5%
Total odor reduction
75 oue/m³
Residual odor from 15.000 oue/m³ input
30x peak
Maintained removal during peak

Small share of mass. Large share of odor.

In sludge processing air, volatile organic sulfur compounds may represent only a fraction of the total mass, but they can dominate the odor impact. At WWTP Utrecht, DMS, DMDS and methyl mercaptan were identified as key odor-causing compounds.

Which compounds drive sludge odor?

To understand these dynamics at WWTP Utrecht, measurements were performed in November 2024 and March 2025, capturing two operating periods. In both cases, GC-MS measurements show that the bulk of the gas consists of sulfur-containing gases (predominantly volatile organic sulfur compounds; VOSC) and a mixture of aldehydes, aliphatic, aromatic and cyclic hydrocarbons.

While the VOSC account for about a sixth of the mass, they account for more than half of the odors. The main culprits are dimethyl sulfide (DMS), dimethyl disulfide (DMDS) and methyl mercaptan.

The AirShield eliminates the mix of odors

Our AirShield is designed for broad-range sludge odor control, targeting multiple malodorous gases in a single system rather than targeting a single compound. It is electrically driven and uses sensor-driven power control to adapt cleaning capacity to the odor concentration.

GC-MS measurements showed 100% removal of DMS, DMDS and methyl mercaptan. Dynamic olfactometry showed residual odor emissions of 75 ouₑ/m³, corresponding to a 99.5% reduction from 15,000 ouₑ/m³ input.

Removal of sulfur-containing gas
Removal of total odor
75 ouE/m3
Residual odor emissions
from 15,000 ouE/m³ input
“In the past, when we experienced odor issues, they were mainly caused by dimethyl sulfide, mercaptans, and other sulfur-containing emissions from our sludge treatment.

Luper’s AirShield removes these compounds with 100% effectiveness.”
Marijn van de Ven
Process Technologist,
Hoogheemraadschap de Stichtse Rijnlanden

What this means for operators

With our AirShield, you are able to:
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- Eliminate a wide range of persistent sludge odors
- Prevent odor complaints before they arise
- Obtain consistent performance across changing conditions

Why AirShield for sludge lines?
Biofilter
Carbon filter
AirShield
Handles sulfur odor peaks
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Treats mixed compounds
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Electric-based
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No chemical dosing
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Low TCO
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Want to assess sludge odor peaks at your facility?
Request assessment
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FAQ
Which pollutants does the AirShield remove (H₂S, DMS, VOCs)?
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The AirShield is designed to treat toxic and odorous gases at wastewater treatment plants and other industrial facilities. Target gases include sulfur-containing compounds such as H₂S and dimethyl sulfide (DMS), amines, aldehydes, terpenes, aromatics and other odors and (very) volatile organic compounds (VOCs).

A stand-alone unit can effectively treat peak concentrations of up to several hundreds parts per million (e.g. 750 ppm for H₂S). We offer site assessments to confirm that the AirShield is suitable for your specific airflow.
What removal efficiency and outlet concentrations can I expect?
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The AirShield will be configured to suit your site-specific requirements, such as the maximum residual emission and/or required removal rate. In field operations at wastewater treatment plants and pumping stations the AirShield shows removal rates of >99% with residual odor concentration of <75 ouₑ/m³.

We offer assessments to determine the expected performance on your airflow
How is the AirShield’s performance verified?
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The AirShield has built-in sensor slots for (remote) output and status monitoring. We provide data-enabled services such as emission monitoring and reporting, performance optimization and predictive maintenance.

If desired, we offer onsite pilots and demonstrations to validate performance under real operating conditions.
How does the AirShield clean exhaust air?
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The AirShield cleans air based on our patent pending gas-phase advanced oxidation process (GPAO). The goal of our GPAO process is to neutralize toxic and odorous gases, turn these neutralized gases into particles and then remove the particles from the air.

This sequence is completed because particles are easier (and thus more cost effective) to treat than gases.
What is the total cost of ownership (TCO) of the AirShield?
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The TCO depends primarily on treated airflow (m³/h), pollutant load and variability (e.g., H₂S/DMS peaks), operating hours, and the required outlet target. Operating expenses are typically made up of electricity consumption (Wh/m³), planned maintenance and service, and consumables such as filters and sensors.

During a site assessment we provide a TCO estimate for your location, including typical and peak energy use, expected maintenance intervals, and consumables, so you can compare CAPEX and OPEX against alternatives such as activated carbon, biofilters, or scrubbers.
How much electricity does the AirShield use?
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Electricity use depends on airflow rate, inlet concentration, temperature and humidity. Typical ranges are 0.5 – 1.5 Wh/m³ for low concentration airflows at up to 5 Wh/m³ for high concentration airflows (incl. fan).

The AirShield minimizes energy consumption by matching operating power to pollutant concentration based on sensor feedback. Using the specifics of your airflow we provide typical and peak energy consumption estimates.
Does the AirShield require (storage of) chemicals?
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No, the AirShield uses electricity and the water and oxygen naturally present in the air to generate reactive species in-situ for oxidation. Any residual reactive species are converted downstream using an integrated catalyst.
What maintenance is required and does it require special staff training?
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The yearly maintenance is designed to be straightforward and can be performed by a trained operator, a local service partner, or our team, depending on your preferences.

Tasks include inspection, checking sensors, and scheduled replacement of consumable components. We can provide service agreements and planned maintenance to ensure reliable performance. If desired the AirShield can be equipped with sensors for predictive maintenance.