Chasing Landfill Odors: Part 2

Chasing landfill odors is a never-ending job. Operators are forever promised solutions, but today there is no way to completely prevent or mitigate every trace of odor. Where massive tons of waste accumulate, there will be stink. But in this two-part series, we gain insight to better understand and improve on odor control.

Part 1 focuses on technologies and a partnership between two odor-mitigation companies to combine their offerings for what they believe is a better solution than they could offer apart.

In Part 2 a landfill odor expert discusses odor analytical detection methods; new tools such as fate and transport odor modeling; and what’s the best mitigation approach in which landfill scenario.

In this Q&A Nevzat Turan, principal of Weaver Consultants Group, provides insight on odor control.

Waste360: What are strategies to detect odors?

Turan: Although nose detection never gets old, Weaver Consulting Group uses analytical methods only.  Mainly we rely on methods in EPA/625/R-96/010b (Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air). And we perform our own gas chromatography–vacuum ultraviolet spectroscopy (GCVUV) method in collaboration with a university in Texas.

Waste360: What are challenges as you try and isolate the source, and how do you address them?

Turan: Challenge depends on what you are sampling for. For example, if you are sampling a chemical for a particular design and odor control system the challenge is figuring out where you will sample and  how much dosage you will need.   Once you have these answers, before sampling, do necessary forensics, including gathering data on physical and climatological factors.  This may get very challenging in certain cases such as river floodplains.

Waste360: What are evolving trends in this space?

Turan: As I mentioned, doing analytical testing and lab-scale performance verification.  This is very important as engineering a system that involves open air is already challenging. We do not leave anything to guessing when it comes to performance of the odor-eliminating chemicals.  Also, fate and transport modeling for odors is now a readily available tool that uses site-specific source, terrain, and climatological data.

Waste360: What’s unique to odor control at landfills vs materials recovery facilities (MRFs), transfer stations, commercial composting, and wastewater treatment plants?

Turan: I consider the following unique characteristics of each:

MRFs: in general, these are the easiest facilities to handle as in most cases incidental quantities of odor-causing chemicals are involved. However, odor-causing chemicals exist, and these facilities happen to be closer to crowded areas.  Also, depending on what is recycled (all inert materials, dry wall, concrete, etc.) and facility design, challenges would be site specific. However, especially for the enclosed operations, engineering of the odor control system would be straightforward.

Waste Transfer Stations: In general, transfer station operations occur indoors, which makes it significantly less challenging to design for odor control; odor control chemicals and odor molecules can much easier find each other in enclosed spaces.

Commercial Composting: I consider this as a non-issue as there are a menu of solutions with topical applications and they are very effective.

Wastewater Treatment Plants: These operations have relatively larger footprints compared to MRFs and transfer stations. However, they still have confined conditions where an effective odor control chemical should be able to address most problems.

Landfills: Landfills come in all sizes of waste footprints and working faces.  Additionally, incoming waste types may have significant impact on odor generation.  Within the general area where a landfill is located, developing a successful odor control system requires significant data gathering (receptor, other sources, climate data, modeling) and analysis.   

In general, after everything is done to prevent departure of, or creation of odorous compounds at the source the answer to this question (and most odor questions) has three parts:

2.Check operation: determine if there is anything that can be done (including using topicals) to prevent generation and to minimize rate of odorous chemical emission.

3.Design the odor control system: depending on the source and receptor a design should be site specific (including location, climatological conditions, times of the day, days of the year, etc.).

The best solutions can be topical, aqueous, and nonaqueous.  It has been demonstrated that nonaqueous systems are far superior to aqueous systems as they provide an enormously large impact zone compared to aqueous (misters) systems.  Also, nonaqueous systems operate in below freezing temperatures. 

Waste360: What is the best mitigation approach in which landfill scenario? And how do you determine that?

Turan: The best mitigation approach is to leave as little as possible for the odor abatement system.  Because even the most effective odor control chemical will still require finding the odor-causing chemical and, in enough quantity, to balance the stoichiometry.  We are now moving towards optimizing the control systems by better understanding how the receptors are getting odor.

Waste360: What challenges do landfills encounter as they bring in more types of odor-generating wastes? What can they do about it?

Turan: The main challenge has been largely wastewater treatment (domestic/industrial) sludges and aged waste due to significant travel time.  They have decomposed significantly and it’s more challenging to control odor as you place them on the working face. 

Sludge in particular may require solutions at the source, before it reaches the landfill.

Unless landfills stop taking specific wastes, there is a plausible solution that involves working face operations and two-stage (at working face, and perimeter) odor control.

Waste360: How are landfills impacted when they co-locate with compost facilities and or other odor-producing operations?

Turan: Composting and landfill operations have very different characteristics as compost operations are stationary and odors can successfully be managed using topical applications (i.e., not much capital cost). However, landfills (i.e., working face) spatially and vertically are not stationary; thus the source of odors is a moving target.  This has a host of issues including power supply for odor control equipment, location of odor controls, portability issues related to odor control equipment.

Waste360: How do you reduce odor complaints in communities?

Turan: The way to do it is to eliminate odors if they are identified to be coming from your facility.  Developing good relationships with neighbors and educating them with actual site data will help (this would help for everything else the facility does). However, without showing genuine effort and recording success, it may present challenges.

Waste360: What is trickiest about getting communities to understand when odor is generated by landfill and when it isn’t?

Turan: Be in front of them (open houses, etc.) more than anyone else and educate them about the site and general area.  Let them know what your facility is and what you are doing there.  Also, always demonstrate genuine effort – start with the thought that nobody can be fooled.

Waste360: What advice can you give landfill and commercial compost operators around working with communities to assure them operators are staying on top of odor?

Turan: Gain their trust.  You will know that you did when they call you before they call the regulatory agency.

Waste360: What’s the difference between neutralizing and masking odors?

Turan: Neutralizing (and deodorizing) is an attempt to eliminate an odorous chemical before it reaches to receptor’s nose. Masking is an attempt to reach to a receptor’s nose with a “pleasant smell” in a timely manner so that receptor is not bothered by odorous chemicals.

Neutralizing (and deodorizing) involves conversion of an odorous chemical to a non-odorous chemical (either chemically or  biologically).  The success of the effort results in no smell (good or bad).

Masking is feeding more powerful (hopefully more pleasant) smelly compounds to the ambiance where odorous chemicals are so that receptors smell more pleasant chemicals.  Regardless, there is a smell. 

Waste360: During what times of the day and or what seasons do landfills smell worse and why?

Turan: After sunset and before sunrise and the wintery half of year (starts sometime in October and ends early April, but it varies by location).  Main reasons are losing photo degradation, lower temperatures coupled with atmospheric inversion.  Interestingly, I have not seen much academic work related to micro scale atmospheric inversion.

Waste360: Can you do anything to ward it off before it happens?

Turan: After addressing all issues regarding gas control and collection systems (GCCS) and leachate management, managing daily cover correctly and operating large impact odor control systems overnight will address the problem.

Waste360: How do odors move offsite? How do you stay on top of this problem?

Turan: The controlling mechanism is mass movement of air (wind or inversion).

Odor control plans should be developed with a year around action plan approach. Otherwise, it may become very challenging.  Year around planning also allows operators to develop and secure their odor control budgets ahead of time.  Acting quickly may require costly (e.g., stop taking a waste stream, etc.) changes to operations if the site is caught unprepared.  

Waste360: What’s most key to success in managing odors?

Turan: Regardless of what odor control strategy and technology are used, if an odor control infrastructure and a sound site operating plan are not in place, it will always be an uphill fight.  Everything, including GCCS, leachate management, working face operations, stationary and portable odor control systems (wintered as needed) must be working coherently to record success.

Waste360: What’s your best advice on staying in regulators’ good graces?

Turan: If the “team” that includes site operators, neighbors, and the regulatory agency staff is not established and not operating in cooperation then the operators will always deal with challenges. The core ingredient of this is the level and sincerity of the effort by the operators.

Waste360: When odor happens at landfill, how often is trash at the working face the root of the problem? What are other common issues?

Turan: Trash is the root very often. Inbound and outbound truck traffic, GCCS operations, and leachate management are also issues.

It is important to eliminate the potential for generating odors from non-working face odor sources and leave only the incidentals to odor control.  Trash (or working face) is the main source most likely because other potential sources are under control.