A new standard, NFPA 56 (PS), Fire and Explosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems, now covers transport and delivery of landfill gas to an end use. In the past, these gas delivery piping systems did not require purging and they have been treated similarly to the gas collection systems in the landfill. No more!

First, let’s be clear – NFPA 56 (PS) does not apply to LFG collection and control systems (GCCS). It is only applicable to piping that leads to an onsite or third-party user that is not employing a simple flaring system, for example, engines, turbines, boilers, fuel processing, or pipeline injection.

Who needs to meet the new standard?

From a practical perspective, the standard does not apply to you if your site is simply extracting and flaring LFG to maintain environmental compliance. However, if you are sending gas to a secondary use, whether it’s an internal project or a third-party operation, you now have some additional protocols to consider.

Highlights of the requirements in NFPA 56(PS) include:

• Use of flammable gas for internal cleaning of piping systems is prohibited.
• Cleaning new or repaired piping systems, placing piping systems into service (purging), and removing piping systems from service (purging) are all covered.
• Development of written procedures and a safety validation of procedures by competent persons is required.
• Examples of purge procedures based on requirements in the standard are provided.

Why was the new standard implemented?

Like many regulatory requirements, the new standard came about because of a tragic accident. The National Fire Protection Association (NFPA) acted to regulate flammable gas delivery systems due to an urgent recommendation from the US Chemical Safety Board (CSB) following a disastrous accident at a power plant that was using high-pressure natural gas to clean a recently constructed pipeline. The uncontrolled exhaust was ignited, resulting in an explosion that killed six workers and injured 50 others. This was considered a fairly routine procedure that had been replicated without reported incidence many times before, at this facility as well as others.

In a direct response to this incident, the NFPA developed 56 (PS) to address not only the cleaning practice known as “gas blows” but also a broad range of gas process activities, such as purging into and out of service, pipe cleaning, repair, replacement, and removal procedures conducted at power plants, and industrial, institutional, and commercial applications. LFG and other biogas delivery systems fall under the definition of this standard.

If you want to know more about the new standard, check out New Directions for LFG, an article written by Steve Wittmann and me that appeared in the January-February 2013 issue of MSW Management.

I thought others in the industry might find this interesting, so here goes.

Some of the more advanced sensor systems are manufactured by MSA. These are what I will call “accurate” sensors. That is, they measure methane to a specific tolerance repeatedly, at the expense of needing to be calibrated at set frequencies. Due to their accuracy, alarms can be triggered at precise measurement values, which may be a permit requirement, such as 20 percent LEL, as opposed to a detection of gas between a broad range of measurement values.

Two basic setups for these sensors are shown below:

Standalone individual sensors (few $1000s) – Useful in situations where you have large spaces to monitor. If you were concerned with methane intrusion into a building, and had multiple occupied first floor rooms, such as an apartment building, each of these separate spaces would require its own sensor. Depending on the number of rooms, this could get costly, not even taking into account a hassle to routinely check and calibrate each sensor.

One sensor, multi sample locations (starting $30,000 and increasing with options) –  If you were to require monitoring of numerous locations, this type of system can monitor up to 32 separate locations up to more than 500-750 feet from the system sequentially, utilizing one central sensor. So, when it comes time to check and calibrate sensors, there is only one sensor to deal with. In addition, up to two other sensor types can be installed to monitor other potential gases. Monitoring records can be printed on a daily basis or accessed over the internet.

If you need something simpler, there are sensors similar to a typical household smoke detector, which will alarm at some point between 10 and 25 percent LEL (per UL 1484). These do not have to be calibrated and do come with a relay option to wire into a building alarm. Best of all, they are inexpensive (~$100), although they will need to be replaced after approximately 5 years.

When it comes to methane sensors, or any other indoor air quality sensor, there are a multitude of choices out there, with varying levels of functionality and price points. The decision on which specific sensor to use needs to consider and balance both regulatory requirements and sensor capital and maintenance costs.

Landfill gas well at inactive landfill

Everyone knows how difficult it can be to meet New Source Performance Standards (NSPS) requirements at older inactive landfills. Recently, we were successful at getting approval for an alternative operating scenario for a facility with an older inactive landfill, which will let the owner operate the gas collection and control system (GCCS) without the limits on oxygen, temperature, and pressure and the complications that go along with them.

I thought it was an interesting option for facilities that are subjected to NSPS and required to install a GCCS, and wanted to share my thoughts on the subject.

By an older inactive landfill, I mean one that is a closed landfill or area of a landfill, with final cover and a decreased landfill gas (LFG) flow. As a landfill ages, LFG production decreases and the GCCS may require a little extra attention to keep things running smoothly. Even if the wells are operated and maintained properly, low methane/flow conditions may cause problems.

Regulatory limits can be tough for older inactive landfills to meet, which can lead to exceedances, notifications, and expenses, including staff time and potential fines. The use of an alternative operating scenario may be a good option to consider when there is enough LFG to keep collecting it. When operating, the facility acts as a “good neighbor” since odors, surface emissions, and subsurface migration are controlled with the continued use of the GCCS.

At the facility in question, an inactive area of the landfill met the requirements to remove GCCS by itself, but the facility wanted to continue to operate the GCCS, but without having to meet the operating limits required by NSPS. To do this, the facility developed an alternative operating scenario for the older inactive landfill.

The process started by discussing the wellfield, lateral migration, and surface emission monitoring data, liquid levels in the wells, well integrity inspection results, and records of condition/age of waste in the area with the regulatory agency. The process concluded with a letter that demonstrated to the agency that even with oxygen, temperature, and/or pressure levels exceeding required thresholds, the GCCS of the inactive area of the landfill was still effectively managing emissions.

The agency approved the request and revised the air permit. The new air permit requires monthly monitoring of pressure, oxygen, and temperature, of each well and quarterly surface emission monitoring of the older inactive landfill. The facility does not need to perform follow up corrective actions or expand the collection system after an uncorrected exceedance at a well. However, follow up corrective actions and re-monitoring has to be done if there is a recorded surface emission monitoring exceedance.

Garth Bowers discussing modeling results at GWMS

Everyone knows that proper delineation of floodplain limits and design of surface water management controls is an important part of any landfill design, whether it’s an initial facility siting/design or an expansion. Part of that delineation usually requires use of computer modeling of existing and proposed surface water conditions.

Over the years I’ve used both one-dimensional and two-dimensional models, but recently I was involved in a project where both were used and the results compared. What that comparison shows is that both one-dimensional and two-dimensional modeling has a place in siting and design of landfill facilities. No big surprise here – but I thought I’d share the results of the study so others can see which one might yield the best results for their projects.

The one-dimensional models run quickly and can be used to demonstrate that proposed facility designs comply with the requirements of 40 CFR §258.11. They are also great for evaluating multiple facility design configurations to identify proposed locations of channel banks and grading that won’t cause surcharging outside of the facility boundaries.

On the other hand, two-dimensional models typically require more set up and computational time and, this means they don’t lend themselves as well to quick evaluation of numerous alternatives. But the plus side is that they provide a more detailed evaluation of flow conditions throughout the modeled domain, including variations in flow depths, velocities and directions across the width of the floodplain, which may be required to demonstrate compliance with local floodplain requirements.

If you develop floodplain limits using this type of more detailed evaluation of flow conditions, you may be able to better optimize proposed designs, compared with designs based on floodplain limits developed using one-dimensional modeling techniques or floodplain limits taken from FEMA FIRM maps. These optimized designs may allow additional landfill airspace within the existing facility property, deferring the need for additional property acquisition or new landfill siting.

I think that there could be a lot of value in using a two-stage process, in which a one-dimensional model is used first to quickly evaluate flow conditions at a site and develop preliminary configurations of site improvements. Then, once the preliminary configuration is identified, a two-dimensional model can be used to “polish” the design and identify locations where additional space for site improvements can be obtained with little or no impact on off-site flows.

For anyone interested in seeing more of the details of the comparison between one-dimensional and two-dimensional modeling, I recently did a poster presentation for the 2012 Global Waste Management Symposium in Phoenix. If you’d like to discuss it further, please email me.

Flare showing continuous biogas pilot line

At the last Global Waste Management Symposium, I presented on the benefits of using landfill gas to power a flare, giving the end user more operational flexibility – say for landfill gas-to-energy or other beneficial reuse systems. I offered three case studies of situations where continuous biogas pilots worked well, along with costs for implementation. A continuous biogas pilot has a place in gas management at these sites, but should be evaluated on a case by case basis.

It is most common for people to be retrofitting (similar to what I presented), but discussion and questions posed after the presentation gave me a new understanding that new flares being produced by certain manufacturers have a much higher turndown capacity than the traditional 10:1 seen in older flares. While retrofits are still more common than installing new flares, new flares have the ability to take much lower flows right out of the box, which benefits LFGTE operational flexibility.

Also at the GWMS, an interesting breakout session focused on the solid waste impacts of shale fracking. A client was discussing this with me after the presentation, and told me that on some of their sites, they are getting nearly 50 percent of their tonnage from fracking waste cuttings, which present some big picture operational issues.

The material coming into the landfill needs to be dewatered and mixed with MSW in a strategic manner so structural issues don’t occur in the future. These are relatively new problems and structural stability issues are just being realized and addressed with relatively little engineering analysis or data developed at this time. In my view, engineering firms who are able to best address the solid waste and environmental water issues related to fracking will have an edge in this rapidly expanding service area.

For some facilities with excess LFG, or with local or regulatory compliance issues, the reduced flow might be a benefit. But for many others, reducing LFG flow may mean revenue losses. If not anticipated and properly planned for, these will become an unpleasant surprise in the future. If you are responsible for a facility with existing contractual obligations to supply LFG to a landfill gas -to-energy (LFGTE) facility, you should begin planning now to avoid these impacts.

Luckily, there are ways that reduction in LFG flow can benefit the landfill. For example, owners may be able to save on gas collection and control system (GCCS) costs because of the reduced flow. Operational costs may also be reduced. And in some cases, where expected excess gas requires LFG flaring, a reduction in LFG flow can actually help the long-term bottom line. Here are two real-world examples of the effects on LFG flow from diverting a percentage of the organic fraction.

Landfill life and LFG production extended

In Case 1, I assumed that the landfill is most interested in landfill longevity and the reduction in organics has not been replaced by inorganic waste.

For this example, while the peak of the LFG curve decreases, the life of the landfill is extended by up to 7 years and LFG production is also extended, which ends up resulting in revenue from energy sales being realized further into the future.

In Case 2, I assumed that the diverted fraction is replaced by inorganic waste. Each scenario would have the same closure date, however the more organics are diverted, the less LFG is generated, and there is the potential for substantial losses from energy sales.

Diverted fraction replaced by inorganic waste; potential for substantial losses from energy sales.

In either of these cases, the size of the GCCS was reduced because of organics diversion. An example site I developed shows cost savings of more than $3 million dollars, through reduced pipe sizes, and reduced engine and flare capacity required.

So to sum it all up, possible negatives of organics diversion include lower revenue from energy sales, the possibility of not being able to meet contract requirements, and a reduction of LFG flow that is not recouped if the organic portion is replaced by inorganics. And the plus side? Lower GHG emissions, potential savings from smaller GCCS, fewer engines and reduced flare capacity, potentially lower operating and maintenance costs, and the possibility of extending the LFG flow (and as a result revenue from energy sales) long into the future.

Regulator attached to nitrogen tanks

We all make protection of human health and safety our top priority, but you also should know about the General Duty Clause. There are standards of care in our industry, and simply meeting statutory requirements may not shield an entity from all liability in the event of an accident!

My advice is that you pay specific attention to the interrelationship between state and local fire, building, and pipeline safety codes, and the provisions set forth by OSHA, U.S. EPA, U.S. DOT Pipeline and Hazardous Material Safety Administration (PHMSA), National Fire Protection Association (NFPA), and International Code Council (ICC).

It’s also important to understand the sheer scope of what is covered by the regulations. Extraction wells and vents, vacuum and pressure piping systems, blowers and compressors, treatment systems, digester tanks, flares and gas engines all may contain LFG/biogas in explosive or otherwise harmful concentrations.

Safety considerations relevant to design, construction, maintenance, and operation of LFG/biogas facilities are contained in many different regulations and standards. I’ll list them here:

• Process Safety Management (PSM), which includes Process Hazard Analysis (PHA)
• Hazardous Waste Operations and Emergency Response (HAZWOPER) standard
• International Fire Code (IFC)
• National Fuel Gas Code (NFPA 54)
• International Fuel Gas Code (IFGC)
• Cleaning and Purging of Flammable Gas Piping Systems (NFPA 56PS)
• National Electric Code (NFPA 70)
• Vehicular Gaseous Fuel Systems Code (NFPA 52)
• Pipeline Safety Regulations (49 CFR 190-199)

I’ll explore the applicable provisions of these regulations and standards in an upcoming white paper – stay tuned!

This year, I engaged vendors I don’t always talk or pay attention to; I made a point of listening to their messages and entertaining more of their questions. What I found was a genuine concern for the industry’s wellbeing and prosperity. I came away from the conference with a renewed sense of “family.” Vendors are committed well beyond the mindset one may simply expect, which is, “I have products and services I wish to sell.” What I found was that the overall goal of the waste industry’s vendors is NOT simply to sell more products, but to provide something that is so much more.

Solid waste industry representatives visit the booths and discuss their trials and tribulations, and vendors are intently listening to the waste industry representatives concerns. They are internalizing these conversations. They are taking the information back to their companies and trying to develop ways they can improve their products and services to assist in tackling these trials and tribulations.

Now, this is extremely interesting to me personally, because I am a compliance consultant and my bread and butter involves networking and coordinating many different vendors. We compliance consultants even routinely find ourselves interacting with direct competitors. These relationships can have their ups and downs, but as long as the vendors focus on the common objective of serving the client’s/waste industry’s best interests, we can accomplish more together. Both companies have relationships with supporting vendors and suppliers that can be brought to bear to accomplish our joint objectives.

At WASTECON, I learned about several new products and services, and I forged new alliances with vendors. I also witnessed many other vendors doing the same. Maybe even more importantly, vendors are creating synergistic relationships to serve the industry better than they have previously. Overall, it was very pleasing to see that vendors are genuinely interested in learning more from the waste industry representatives not purely for the business and sales relationship, but rather to fully support the waste industry and address its needs, because everyone in it considers themselves part of a very large “family.”

One of the most important recommendations is that available analytical data should be periodically evaluated to update the background. What does this mean? For semi-annual monitoring, you should update background every 2-3 years. This will identify any potential changes in baseline groundwater conditions, as well as increase the power of the statistical analyses and reduce statistical false positive and negative rates.

This is so important, because all statistical tests used to evaluate groundwater monitoring results are predicated on having appropriate and representative background measurements. If an outlier value with much higher concentration than other background observations is not removed from background prior to statistical testing, it will tend to increase both the background sample mean and standard deviation, which may also substantially raise the magnitude of a control limit (in case of a parametric analysis) calculated from that sample.

If this happens, a subsequent compliance result will be much less likely to identify a statistically significant exceedance. The same is true with non-parametric analysis. If the maximum is an outlier not representative of the background population, few truly contaminated compliance wells are likely to be identified by such a test, thereby lowering the statistical power of the method and the overall quality of the statistical monitoring program.

The guidance also recommends getting a high number of background observations. Occasionally updating the groundwater monitoring program to increase the participant size will help decrease the occurrence of statistical false positive and negative rates. In short, exclusion of potential outliers and other trending values, as well as a higher number of background observations, contributes to a successful background update.

I’ve been in the solid waste industry for just under five years, and as a first time attendee, I wasn’t sure what to expect of the symposium. I understood there would be an exhibition hall, and in separate conference rooms there would be presentations. Part of me even wondered, “Why do they do this?”

But after attending a few sessions I began to see why. The presenters were sharing tips, tricks, techniques and lessons learned, which I really found helpful. (One guy even shared a picture of his brand new granddaughter.) They were describing new and better ways to get things done, from liners and leachate handling to capping, closing and post-closure management. Did you know that leachate can be used for irrigation? Word for the day: Phytoremediation.

In the exhibition hall there were new and improved products of every kind. You could see the latest in pumping equipment, specialized, simplified and streamlined, some even solar powered. As a relative newcomer, I found it very inspirational and a great way to pass along tons of information.

I met a lot of people too. It was easy – everyone was always “Pleased to meet ‘cha”. My new acquaintances include a professor from the west coast, a small hauling company owner from Haiti, and quite a few others from places and occupations in between. I also ran into people I haven’t seen in quite a while. The entire experience was great. Uplifting in a way. I have a new appreciation for this industry which is consistently endeavoring to improve the business, public relations and public health.

I was going to write a song about the experience, and I still might. I just need to find some words that rhyme with symposium. Then maybe I can compose me one?