Wastewater expert Dave Parry visits Atotonilco Wastewater Treatment Plant in Mexico City to help start up the world’s largest anaerobic digester complex.

By: Dave Parry, CH2M Senior Fellow Technologist and Vice President

At CH2M, we love tackling the world’s most complex problems and seeing the opportunity within, which is why we are excited to be working with Mexico’s National Water Commission (CONAGUA) on implementing Atotonilco, a new wastewater treatment plant (WWTP), which will help sustainably manage Mexico City’s wastewater and stormwater challenges. Check out this video for more details on the project!

CH2M Atotonilco WWTP Team

Serving as Program Manager and owner’s engineer, CH2M has played a critical role in overseeing and implementing start-up activities at the Atotonilco Wastewater Treatment Plant.

Digester at the Atotonilco WWTP

For the last several months, I have been working as part of the commissioning team in Mexico City, on behalf of our client, to help start-up, Atotonilco—a career highlight for me. This is the world’s largest wastewater treatment plant built under a single project and the first facility of its kind. Its size makes it unique, but even more so, the treatment processes that will be utilized at the plant make this project one that will be used as a model for other large cities in the future.

Atotonilco digesters and combined heat and power (CHP) system

Construction of the Atotonilco WWTP began in July of 2010, and it is anticipated to be fully operational in 2016. We’ve made significant progress towards this goal with 26 of the 30 anaerobic digesters (13,000 m3 or 3.4 MG each) now operating. The biogas from the digesters are being used to fuel three of the four boilers for digester heating. After the digesters are commissioned, the combined heat and power (CHP) system consisting of twelve 2.8 MW CHP units will be started up. This was particularly challenging because no digester seed sludge was available from other installations.

Atotonilco was designed to clean nearly 60% of wastewater and stormwater produced by the Metropolitan Area of Mexico City, (compared to 8% before). It has maximum capacity to treat 50 m3/s. It will help Mexico address its irrigation and agricultural challenges by providing 80,000 hectacres of farmland with reclaimed water. While wastewater has been used for irrigation in the area for nearly 100 years, the new level of treatment will help mitigate public health and environmental problems.

Throughout my career, I’ve worked on some great projects, but this one certainly tops the list. I’m looking forward to being back in Mexico in the coming months and will provide an update on the plant’s progress then.

Dave Parry, who joined the firm in June 2015, serves as a senior technical consultant and project manager in CH2M’s water team. Located in our Bellevue, Washington, office, Dave is an expert on anaerobic digestion, co-digestion, co-generation and thermal hydrolysis technologies—bringing special knowledge of effluent heat recovery, pyrolysis, solids processing and energy projects. With more than 35 years of experience providing planning, design, program management, and construction and operational assistance for wastewater treatment, solids processing and energy projects, Dave is a recognized leader in the industry.