Garbage handling

In general, the negative image of garbage comes from the fact often smells when microorganisms grows on food waste. When garbage is destined for incineration, odor release occurs in the steps before the incineration oven, namely when the garbage is moved between containers or containers are opened. During these stages it is difficult to fully enclose the process and contaminated air escapes, the general problem areas are shown in the figure below:General waste incineration process

 Garbage bins needs to be maintained and emptied frequently to reduce odor, if the bin contain large quantities of waste the odor in the nearby area becomes significant if not tightly sealed, the smell is especially relevant for organic wastes, that perhaps has not been collected for logistical reasons. Although, for low garbage quantities the generated smell is diluted sufficiently to avoid complaints. 

Odor becomes an issue if released in close proximity to people and in large quantities, for waste managing plants all garbage trucks have to unload their waste into large storage containers, the process of transporting the garbage from the trucks inside the plant releases odor, especially if a conveyor belt system is used. 

In the plants internal waste storage varying quantities are stored to ensure a continuous feed for incineration. At this point garbage is handled in large semi-open rooms, the air is stirred up by falling garbage, movements from cranes and convection flows. Such large rooms are difficult to close and it needs to be semi-open to allow easy loading and handling, to limit odor spread the waste can be treated in the tank or displaced with huge ventilation systems.

Semi open room for garbage handling

There are several strategies for reducing odor complaints and improving work conditions:

  • Closing the process and treating off gas
  • Have a short garbage to treatment cycle
  • Keeping the process far away from local residence, thus reducing complaints
  • Eliminating odor causing microorganisms
  • Frequent emptying and cleaning of equipment
  • Make employees wear protective gear

Current technologies available for reducing odors in large open rooms are few. Treatment processes that can be employed directly on garbage include spraying the waste with different solutions, such as bacteria solutions adapted for odor removal. Technologies based on water systems increases the moisture content of the garbage, which causes inconveniences in terms of weight increase and leaching of organic compounds into difficult to reach crevices which cannot be cleaned without stopping the process. For an incineration plant washing techniques reduces the net energy release since additional water needs to be vaporized. Furthermore, the active solution needs to be purchased, stored and constantly maintained.

Classical odor capturing techniques perform well in reducing odor, such as activated carbon which requires the odor to be collected in ventilation and requires storage and replacements of adsorbent with associated costs and man-power. Comparison of three treatment technologies are compared relative to eachother in the table below:

 

Ozone treatment

Wet treatment

Activated carbon

Maintenance frequency

 Low  High  High

Consumables

 None  High  High

Pressure drop

 Low  Low  High

Energy cost

 High  Low  Low

Manpower

Low  High  High

Ozone is the best solution for treating odors in large open rooms. In large storage areas ozone can be used to treat the tank air continuously so that when opened, less odor is released. As ozone has a higher density than air, it can be injected at an elevation and treat odors as it sink downward, in contact with garbage it kills bacteria in addition to oxidizing odorous compounds. Using this treatment option does not require chemical storage or frequent replacements, after installation an ozone system produces on demand, production can be increased, decreased or stopped without damaging the system.

With correct installation the injection is positioned so that eventual ozone escaping the chamber is below regulatory limits. Using ozone this way also prohibits bacteria growth and reduces airborne microorganisms significantly, thus reducing exposure to employees. To ensure safety, ozone sensors are installed which warns and shuts down ozone generation if ozone concentrations above safety limits are reached in key locations.

An alternative approach is to treat odorous flows already funneled in ventilations, by simply injecting ozone the ventilation becomes a deodorization reactor, followed by eventual filter solution such as our Nodora product and ozone destruction unit Contra

How severe is your odor problem in a hot summer day? We offer analysis services where we measure estimate odor and pinpoints which kind of compounds are largely present in your case. Please contact us for solutions to your odor problems.

Ozone tech