Written by Martha Powers and Heidi Travis
The large glass geodesic dome pictured on the left graces the entrance to the Marseille Geolide Wastewater Treatment Facility. The interior of the public area of the facility is clean and modern with little hint of what is just underground. The facility is located in downtown Marseille, commissioned in 1987 by the city at a cost of 160 million Euros to build, with a biological treatment extension added in 2008. The design of the facility is at the lowest point of the city and was built underground due to its urban location. This plant serves 17 towns and 1 million inhabitants within the Huveaune river valley. Currently, it is running at 70 percent capacity, with operations at the facility directed by 440 employees.
Previous visits to U.S. wastewater plants in the states of Pennsylvania and New Jersey provided context for our visit. Below are the main differences and similarities between those plants and the Geolide plant.
Private vs. Public. After the Geolide plant was built, it was politically determined that the plant should be maintained privately by experts in the field. Thus Marseille contracted with Suez Environment, who then set up a subsidiary, Seram, to run the plant operations for a 13 year period, ending in 2013. Tour guide and Seram employee Bruno Triboulet explained the entire treatment process and fielded many questions related to operations and output. In comparison, the water treatment facility in Atlantic City, New Jersey is run by a municipal utilities authority, created by the City’s Board of Commissioners. The differences between Seram and a municipal authority could include accountability to a public versus private entity. There are also differences between employees working for government versus a private company which may include benefits and long-term employee engagement.
Costs. Yearly wastewater treatment fees in Marseille are about 120 Euros ($156) per household. To compare, residents in Camden, New Jersey pay slightly more, at just over $300 per household per year. Philadelphia households pay the most– $700 per year for water use. The fee for Marseille residents is considered low, by French standards.
Stormwater Management. Marseille has a stormwater management issue during significant rains because contamination of waterways from flooding present a problem within the current system. The Philadelphia Water Department also faces a similar wastewater management problem because of its combined sewer system and amount of paved surfaces, directly connecting drainage systems to the river. Philadelphia is working on developing extensive green infrastructure to help absorb or catch and slowly release water in order to create a long-term solution. This green work may prove useful to other cities, such as Marseille, that have aging infrastructure and stormwater problems.
Quality Testing. Quality testing in Marseille occurs at exit points, which, for Marseille, means beaches. Sometimes beaches must be shut down if bacteria levels become too high. The Marseille plant’s last step is bio-filtration, which is a quick process through bacteria filter media with added air. Mr. Triboulet said that since the water exits into the ocean, they do not want to harm ecological life with unnecessary additional chemicals. They are currently not using coagulants or flocculants at this stage unless needed to control biological agents. Philadelphia adheres to a different last stage of treatment by adding chlorine, as it releases water directly into the river instead of an ocean. Officials at the Camden wastewater plant say chlorine evaporates before it reaches the river.
When asked about improving removal of contaminants, the Seram staff recommendations included limiting source pollution such as detergents, industrial chemicals, and other endocrine disruptors. They noted that endocrine disruptors are an emerging problem and that they have started actively testing for substances in the past two years. This is a similar sentiment to how U.S. treatment plants are treating the emerging risk of endocrine disruptors. There has been an initial contribution to the public forum regarding baseline data, but so far steps have not been taken to treat this type of contaminant in either country.
One of the most discussed issues amongst all of the plants is concern for air odor affecting the surrounding communities. Each plant makes a strong effort to use air scrubbers to prevent unpleasant smells. Finally, there are many emerging issues related to health and pharmaceuticals in wastewater that are under consideration; however cost is prohibitive until further studies prove that these problems are serious enough to act upon.