If you have ever driven along the Beetham Highway whenever the landfill “belched” out noxious gases, or had to contend with smoke and smog coming from the Aripo landfill during one of its yearly fires, you would know of the value of having clean and fresh air.
The chemicals that come out of the landfills such as toxic hydrocarbons, hydrogen sulphide, and volatile organic compounds (VOCs) wreak havoc on the air quality of the nearby communities and have serious short-term and long-term effects for the people who live there.
One of the exhibitors at last week's 2022 Trinidad and Tobago Energy Conference hosted by the TT Energy Chamber, Morrow Energy, a gas treatment company, may have a solution to the gases coming from the Beetham, Guanapo, Forres Park and Studley Park landfills to deal with the toxicity and bring about an additional source of renewable gas.
Morrow Energy, using special technology and patented chemicals, treats toxic fumes to produce pipeline-quality natural gas.
Dared to change the environment
Areyan Stocks-Gonzales, finance and business development manager, told Business Day that the US-based Morrow Energy Company was established in 1986 by the Morrow family. They started in contract treating and moved on to manufacturing sales and equipment for the conventional oil and gas industry.
In 2000 the company began building landfill gas treatment plants, but how it started, Stocks-Gonzales said, was on a dare.
He couldn’t say who, but said that someone gave the company a sample of gas that they were challenged to treat.
“We figured out a way to treat it and sent it back. It was only after we sent the treated product that we realised that it was a sample from a landfill,” Stocks-Gonzales said.
After the company treated the gas it began developing and designing and commissioned its first plant in Arkansas. Now, it has 24 landfill gas treatment plants, and 16 digester plants which take gases from waste food and manure and convert that into natural gas as well.
Stocks-Gonzales said that while they have been in the landfill gas treatment business for 22 years, over the last five to ten years they built most of their plants.
“We took our decades of treating experience and leveraged that to build a plant that treats the gas, and we were successful,” Stocks-Gonzales said. “The very first plant is still running. Every couple years we would look at more plants but from 2012 we really started building.”
The dirtiest gas ever
Stocks Gonzales said landfill gas is by far, the dirtiest gas that Morrow Energy has ever had to treat.
Conventional natural gas that comes from an onshore or an offshore well is relatively clean, he said. Natural gas has some hydrocarbons, and a quantity of CO2 as well as hydrogen sulphide, but other than that it is relatively clean and easy to treat.
“Landfill gas is by far the dirtiest gas we have ever come across,” he said.
“When you look at landfill gas every gas that you can possibly imagine is there in some concentration or another, depending on the nature of what goes into the dump. There is a lot of variability to it, and because of that it is harder to treat.”
Landfill gas is about 50 per cent methane, which is 28 to 36 times more effective in trapping heat in the atmosphere, making it a much larger contributor to global warming than carbon.
In the US, municipal solid waste landfills are the third-largest source of human-related methane emissions. According to the US Environmental Protection Agency, the methane emissions from landfills in 2020 was the equivalent to 20.3 million passenger vehicles driven for a year.
When a landfill is covered it creates an anaerobic environment for bacteria to break down the trash. As bacteria feeds on the garbage it releases the noxious gases. Short-term exposure to gases such as ammonia and hydrogen sulphide can cause coughing, irritation of the eyes, nose and throat, breathing difficulties and aggravation of asthma. Long-term exposure can also cause nasal blockage, sleep difficulties, weight loss, chest pain, nausea and headache.
Stocks-Gonzales said the main ingredient in its landfill gas treatment process is the chemical Selexol which, at varying temperatures and pressure can select different chemicals in the air.
“Selexol is absorbing and physically pulls chemicals out the gas, grabs it and holds on to it,” Stocks-Gonzales said.
“At one temperature and pressure it will collect soloxines and VOCs and some of the really nasty components, and at other pressures it will absorb carbon. We can treat the vast majority of the hard-to-treat gases and then it is pretty easy to remove the rest of the components.”
Morrow Energy digs a well in the landfills, draws out the gas and treats it.
First, it is compressed for transit through a pipeline, then the hydrogen sulphide is removed through the use of a solid media VOC treatment bed which binds and extracts the chemicals. Then the selexol is introduced, which absorbs the harmful chemicals such as heavy hydrocarbons. The selexol is used to take out the carbon as well, then the oxygen is also taken out with a catalytic O2 unit.
The result is clean, pipeline-quality methane gas that can be used in a list of clean energy solutions.
Stocks-Gonzales said the chemicals that are drawn out of the gas is gathered and incinerated to the point where it would not be harmful.
“There is a small stream of harmful chemicals that you can’t release into the atmosphere, so we incinerate it using a thermal oxidiser,” he said.
“These are chemicals that would have been released into the atmosphere anyway, but we collect it and render it harmless.”
While the methane collection is one benefit of the process, Stocks-Gonzales said one of the bigger benefits of landfill gas plants is the reduction in odour. He said Morrow can withdraw a steady amount of natural gas depending on the size of the landfill.
TT's Solid Waste Management Co Ltd (SWMCOL) said landfills receive about 700,000 tonnes of waste per year, which is two-thirds household waste and one-third industrial waste.
Morrow lauds SWMCOL, Energy Chamber
Stocks-Gonzales lauded the Energy Chamber on its conference, saying it was a great opportunity to meet with several people in the industry.
He said project manager Bob Heath did a lot of work in the regional energy sector and knew of the conference, and the fact that it would be the first time in two years that people in the chamber would meet physically.
“We started looking into it more and more and we realised that you have three landfills that were great candidates for this technology,” he said.
“The experience at the conference was great. It was well put together and well run and was a great opportunity to meet people while we were down there. We were really glad that we came.”
While in TT Stocks-Gonzales also met with SWMCOL and did site visits of the Beetham landfill, to assess whether or not the landfills were in fact good candidates. He also praised SWMCOL on its management of the landfills.
“I thought that the meeting went very well. It was very positive. We see how committed the government is to improving the conditions by the landfills, and the emphasis they are putting on moving in a more sustainable direction. We believe in their mission and think we can help them achieve that goal.”