Pilot equipment: a test to verify different ways of containing odors

Sometimes, if the system is particularly complex, it is necessary to include a test phase with "pilot equipments".

It's a small, scaled equipment, with abatement technologies useful for finding the most suitable solution for the specific application. 

The possibility of carrying out a preventive test with a pilot equipment is the best solution to understand the real efficiency of an abatement system, before purchase and installation.

Carrying out a test with pilot systems capable of reproducing, on a small scale, odor abatement processes and treatments directly on the target emission, is the only way to obtain real information on the current state of an odorous emission. 

The tests are chemical, physical and olfactometric, according to detailed protocols evaluated in the preventive phase and agreed with the customer. 

The sampling strategy involves sampling upstream and downstream of each stage of treatment, in the different phases and based on the needs highlighted by the customer.
The pilot equipment is usually made up of multiple environmental abatement devices interconnected to form a "hybrid" equipment.
All on a smaller scale to treat an emission with a flow rate between 100 and 500 m3/h.

For the selection of the most suitable abatement garrison, it is preferable to test multiple solutions that can work alone or synergistically, such as:

• temperature reduction; 
• condensate separation; 
• dry filtration with multireagent media; 
• multi-stage wet washing; 
• olfactometric finishing with osmogenic barrier. 

After the design phase, test definition with a pilot equipment follows a precise operational protocol for analysis. 

The data that allow prior evaluation are: 

• physical (velocity, flow rate, humidity); 
• chemical (quality and quantity of chemical compounds present); 
• with authorizations (type of licence and any limits); 
• olfactometric (if present). 

Olfactometric tests, according to UNI EN 13725:2004, and chemical tests can be carried out during the experimentation. Field tests and laboratory analysis will be carried out.
The data obtained will allow to understand the variation in efficiencies as a function of the treatment applied. This will be followed by a detailed concluding technical report in which we highlight strengths, and possible weaknesses, of the adopted solution.

The type and conformation of the pilot equipment is defined on a case-by-case basis, and the structure normally employed includes:

• wet tower
• Demister with BSM
• DKFIl multilayer
• olfactometric finishing chamber.

The testing phase usually has a duration of at least 20 consecutive days. To understand in detail how to design and implement a pilot plant, below is an example made by our team of technicians for odor treatment of vents on tanks.

Tank vents are often underestimated from the point of view of odor emissions. In fact, rather often, because of the effluent they contain, they can become a source of nuisance, especially during loading. 

However, the isobar vent of a tank, even operating at ambient pressure, is to be considered in all respects a safety device and its modification or alteration is not 'allowed. 

Capture is therefore an aspect that should not be underestimated and requires careful design. 

The experimental phase therefore becomes indispensable and allows action to be taken at a preliminary stage in order to determine abatement yields precisely because of the pilot equipment of a size and capacity quite similar to the final equipment. 

The duration of this phase was 20 consecutive days and the object of the test was the emissions detected from the vents of the leachate storage silos.

The installation of the pilot equipment

We installed the pilot equipment on the ground near the silos in the area identified during the survey. 

The first stage of treatment required the incoming hose from the storage tanks to descend to about 1 m above ground level in order to connect to the tower inlet. 

 For its operation, the pilot plant required an electrical supply point with the following specifications: 400 V, 50 Hz, 3.0 kW.
 For convenience, it was chosen to have a hose for filling the pilot scrubber tank (max 200 liters) as to facilitate the loading of the plant during operation.  

First stage: wet treatment equipment

In a first phase, we tested a wet abatement system (or wet scrubber), which involved the removal of the pollutants present through the action of water. 

Odor abatement is, in this case, the result of an "air scrubbing" process, in which pollutants are transferred from the gaseous state to a liquid state and neutralized from there. 

 The scrubbing towers that are installed allow the absorption of the liquid part by filling bodies or exchange packs inside a scrubbing chamber, containing the pressurized aqueous solution. Here we installed a wash tower consisting of a vertical-axis cylindrical structure made of polypropylene. 

 A spray ramp with full-cone nozzles ensured backwashing of the effluent and removed the pollutant components of the aeriform stream with an aqueous solution of known titer of base and oxidant.

Second stage: dry treatment equipment

In the second phase of the test, we used a chemical-physical adsorption filter system that does not require the use of any liquid substance and is therefore referred to as a "dry scrubber." 

 This type of solution is very effective for treating air from waste collection rooms, composting facilities and silo vents, as in the case described.

Electrical panel 

The electrical panel is equipped with: 

• main switch; 
• recirculation pump switch; 
• voltage presence indicator light; 
• pump malfunction alarm light; 
• STOP and START button; 
• EMERGENCY STOP button.   

Olfactometric tests and chemical analysis planned in the design phase followed.

The sampling protocol

The standard procedure for the detection and sampling of analytical and olfactometric parameters, as mentioned above, was conducted over the time frame of 20 days, equal to the entire duration of the test. 

 To reproduce proper experimentation, the constancy of physical and chemical characteristics of the effluent, odor mass flow, temperature and overall flow rate was ensured over the measurement and sampling period.

The pre-test arrangements and connections

In order to conduct the test, we recapitulate the arrangements and connections made:

The main advantage derived from pilot equipment is to avoid errors in the implementation of the final plant, with obvious savings in overall cost and time. 

 Through the experimentation, which complements the olfactometric tests and chemical analyses planned in the design phase, it is also possible to implement the garrison having the certainty of achieving the set objectives. 

 The final detailed technical report that Labiotest provides highlights, thanks to the measured data, the variation of efficiencies depending on the garrison used, thus allowing the client to assess, without risk, which technology to adopt to solve their emission problem.