The Cloevis technology was developed by researchers from The University of Queensland’s Advanced Water Management Centre (AWMC) to control sulfide generation within municipal wastewater collection systems. Cloevis uses free nitrous acid (FNA) to remove the biofilms that adhere to the inner surfaces of sewer force main walls- including the underlying sulfate reducing bacteria (SRB) that produce hydrogen sulfide.
As a result, gaseous hydrogen sulfide is eliminated. As Cloevis removes the biofilm, treatments are required intermittently and provided as a service program with FNA generated on-site.
USP Technologies, working closely with the University of Queensland, received an exclusive license to use the Cloevis technology. This has led to further refinement of the technology through fields tests in the U.S. which have consistently show it to provide high sulfide removal across a wide range of forcemain situations.
Benefits of Cloevis for Wastewater Treatement
- Avoidance or minimization of on-site chemical storage
- Independence from sulfide loading, retention time or oxygen uptake
- No labor/maintenance requirement
- Removal of hydrogen sulfide odors for up to three weeks after treatment cycle
- Elimination of methane production within the treated segment
- No downstream adverse impacts due to residual treatment chemicals
- Cost similar to caustic shocking and less than nitrate or iron salts
USP Cloevis Delivery Options
After an initial process assessment has been conducted, USP Technologies will develop a tailored treatment approach to meet your specified control objectives.
Three different delivery options are available depending on situational restraints:
- Fully mobile systems where no on-site facilities are required except for an injection point dose line. This is beneficial for sensitive areas as there are no chemicals or equipment stored on-site.
- On-site storage and dosing facilities where chemical precursors are delivered and fully used during each treatment. This is beneficial as treatments are supervised and monitored. In addition, after treatment no chemicals are stored or left on-site.
- Conventional on-site facilities that include chemical storage. This option is ideal for larger lines or secure facilities where chemical storage on-site is not an issue. This reduces delivery frequency and service can be managed remotely.
To verify performance, hydrogen sulfide levels are monitored continuously with the use of OdaLog hydrogen sulfide dataloggers, and treatments are reapplied when sulfides begin to reappear in the transmission line.
Service and compliance reports summarizing program activities are provided at regular intervals to keep customers informed of ongoing program performance.
- Cloevis Biofilm Removal Service Technical Bulletin [pdf: 708 KB]
- Case Study: Sulfide Control with Cloevis Biofilm Removal Service [pdf: 702 KB]