Pilot equipment: test to verify various ways of containing odors

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

It is a small, scaled equipment on a smaller scale abatement technologies useful for finding the most suitable solution in a 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.

Performing a test with pilot systems that allow reproducing odor abatement processes and treatments, on a smaller scale, directly on the targeted emission, is the only way to obtain actual information on the current state of an odorous emission. 

Tests are chemical, physical and olfactometric, based on detailed protocols evaluated previously and agreed upon with the customer. 

The sampling strategy involves sampling upstream and downstream of each treatment stage, during the various phases, and based on the customer’s requirements.
The pilot equipment is usually made of multiple interconnected environmental abatement devices, which becomes a so-called "hybrid" equipment.
Everything 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 equipment, it is preferable to test multiple possibilities that can work alone or synergistically, such as:

• temperature reduction; 
• condensate separation; 
• dry filtration with multiple reagent media; 
• multi-stage wet scrubbing; 
• olfactometric finishing with osmogenic barrier. 

After it has been designed, the pilot equipment goes through test definition to follow a precise operational protocol for analysis. 

The following data allow for prior evaluation: 

• physical (speed, flow rate, humidity); 
• chemical (quality and quantity of chemical compounds present); 
• related to authorizations (type of license and possible limits); 
• olfactometric (if present). 

Olfactometric tests, as of UNI EN 13725:2004, and chemical tests may be carried out during the experimentation. Field tests and laboratory analysis will be carried out.
The data obtained will allow understanding the variation in efficiencies as a function of the treatment applied. This will be followed by a detailed concluding technical report in which to 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 includes:

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

In order to understand some details on how to design and implement a pilot plant, here is an example of a system designed by our team of technicians for odor treatment of vents set up on tanks.

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

However,the isobar vent of a tank, even operating at environmental pressure, is to be considered in all respects as a safety device and no modification or alteration is allowed. 

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

Therefore, an experimental phase becomes indispensable and allows taking measures at a preliminary stage in order to determine abatement yields precisely by means of the pilot equipment having 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 to evaluate emissions coming from the vents of the leachate storage silos.

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 about 1 m above ground level in order to connected in to the tower inlet. 

In order to operate, the pilot plant required an electrical power supply having the following specifications: 400 V, 50 Hz, 3.0 kW.

For convenience, it was chosen to have a hose for the filling of the pilot scrubber tank (max 200 liters) in order to facilitate the loading of the plant during operation.

Overall dimensions of the equipment supplied are approximately 4 sq. m (4 x 1).

First stage: wet treatment equipment

During the first phase, we tested a wet abatement system (or wet scrubber), which involved the removal of the pollutants present by using water. . 

Odor abatement is, in this case, the result of an "air scrubbing" process. This allows pollutants to go from a gaseous state to a liquid state, and get then neutralized.

Scrubbing towers allow absorbing the liquid part through filling bodies or exchange packs inside a scrubbing chamber, which contains the pressurized aqueous solution.

Here we installed a wash tower consisting of a vertical-axis cylindrical structure made of polypropylene.

A spraying device with full-cone nozzles ensured backwashing of the effluent and removed the polluting components of the air stream with an aqueous solution having a known titer of base and oxidant.

Second stage: dry treatment equipment

During the second step 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; 
• light indicating the presence of voltage;

• warning light for pump malfunction 

• STOP and START button; 

• EMERGENCY STOP button.   

Afterwards, the olfactometric tests and chemical analyses that had been foreseen previously were performed.

Sampling protocol

The standard procedure for the detection and sampling of analytical and olfactometric parameters, as mentioned above, , was performed over a time-periode of 20 days, corresponding to the whole test duration.

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

Pre-test arrangements and connections

In order to perform the test, the following arrangements and connections were ensured:

The main advantage due to 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 complementing 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 efficiencies variation depending on the equipment used, thus allowing the client to assess, without risk, which technology to adopt in order to solve his emission problem