For several decades, lobe and multistage blowers were the tried-and-true blower technologies for wastewater treatment plants. Over the past 15...
In what was at one time considered to be one of the most polluted regions in the World, something miraculous has occurred; a viable ecology has been restored. Through thoughtful design and the appropriate use of the clean water it produces, the East Chicago Sanitary District Wastewater Treatment Plant (ECSD), East Chicago, Ind., has become a haven for the successful spawning of chinook salmon, in addition to nurturing freshwater sponges and a variety of other flora and fauna.
"We believe that the salmon spawned successfully in East Chicago because of the well-oxygenated, high quality effluent water that is produced by the wastewater treatment plant," said a report, Salmon Spawn in Treated Wastewater. The report was compiled by Peter Baranyai, ECSD's operations manager; Timothy Early, Aquatic Resource Center, Hammond, Ind.; Lidia Bardygula-Nonn, Center for Great Lakes Studies, University of Wisconsin-Milwaukee, Milwaukee, Wis.; and Thomas Glonek, MR Laboratory, Midwestern University, Chicago, Ill.
In addition, viable freshwater sponges are populating the sides and bottom of the concrete walls of the plant's disinfection contact chamber. The sponges, Ephydatia muelleri, are growing to enormous size within the disinfection contact chambers, and have become efficient filter-feeders. These living organisms are considered biological indicators of clean water since they are destroyed by even minute quantities of pollutants, according to the report.
In The Beginning
In 1986, the East Chicago wastewater treatment plant began to upgrade the vintage 1944 plant to improve its effluent quality by adding filtration and disinfection. By 1989, six Infilco Degremont ABW filters and an ultraviolet disinfection system (to eliminate the use of chlorine) were installed. This is when Baranyai first noticed a change in the effluent quality of the plant.
Months later, he discovered aquatic life inhabiting the receiving stream where the plant's effluent was directly discharged. But it wasn't until 1993 that Baranyai first noticed growth on the walls of the effluent channel. He attempted to clear away the foreign substance, unaware of what was thriving in the tank, but as soon as he removed the colorless algae-like material, it grew back. That's when Baranyai decided to call in an expert.
In February 1995, he contacted Purdue University's department of civil engineering and later, the Aquatic Resource Center (A.R.C.), who confirmed the growth to be freshwater sponges native to Lake Michigan, which only flourish in the most pristine waters.
"They [Purdue Univesity's scientists] said this couldn't be from a wastewater plant," Baranyai said. But he knew better.
Despite initial skepticism, Tim Early, executive director of the Aquatic Resource Center, ventured to the plant to see what all the fuss was about."I expected to see a little piece of sponge," Early said. What he saw amazed him.
Ephydatia Muelleri Galore!
In June 1995, a hesitant crew of divers suited up to take a swim in the wastewater disinfection contact chamber. "We were reluctant until we got into the water," Early said. "What we saw was totally unique! The walls were coated with thousands of sponges."
Sponges are actually colonies. Thousands are supported on a common skeleton of silicon where they compete with each other for space. Early said the sponges will expand until they are a fine line apart, then they will engage in chemical warfare against each other until one overcomes the other and can occupy the entire space. They are one of the most ancient forms of animal life still in existence.
These sponges, when observed living in Lake Michigan, come in a variety of colors, including red, green, and blue. The sponges color comes from the algae that grows inside of them, from which the sponges derive some degree of energy. Growing in Lake Michigan, these sponges are usually found to be 20 to 24 in. in diam.
In the treatment plant's contact disinfection chamber, these same species of sponges live a completely different lifestyle. These sponges do not compete with each other for space, but instead, blend together, living in harmony with one another.
They are also colorless, indicating that algae doesn't grow within them. According to Early, they don't need the algae because there is enough food in the chamber's environment for them to survive and thrive. "They benefit from the high quality effluent that supports this high quality environment," Early said.
Though it hasn't been confirmed and there is some disagreement, experts suspect that fish carried the sponge gemmules, the reproductive structure of sponges, into the effluent channel during their spawning period. Although this is thought to be impossible, it is the only lead the ECSD has. "No one has been able to cultivate sponges [though it has been tried]. We have inadvertently created a sponge farm and fish hatchery," said Early.
Plant and Animal Kingdom
Also found in the chamber was an entirely enclosed ecosystem, including algae, invertabrates, plants and fish. There were dozens of little black fish, smolt, about three inches long, swimming throughout the chamber. After observing the four foot weir that these baby fish needed to leap in order to get where they were, the scientists concluded that they would have had to have been born there.
What evidence was there to support this theory? When the fish were tested genetically, Early and his crew found that they were all siblings, evidence that supports their theory that the salmon were spawned there. After all, commented Early, how else would one find a group of fish all related in one consolidated area. "They could have gotten out at anytime, but they couldn't have gotten in. These fish wanted to be there," Early said
According to Early, this is the first documented evidence of salmon spawning in southern Lake Michigan. Instead, salmon are stocked seasonally. Why? In the mid-1960s the population of alewife fish was so astronomical that they began to create big problems for coastal cities.
Early said that during that time, when these fish would die, their dead bodies would crowd the coastline, which was unsanitary and odorous. In order to control this problem, various state agencies stocked the Lake with the fishes predators, Chinook salmon.
Within no time the salmon had feasted enough that the problem disappeared, leaving what today is a multi-million dollar industry: sport fishing.
Nature Takes Its Course
In October 1995, the scientists tested recently dead adult salmon that had swum upstream into the chamber (as salmon instinctively swim upstream when it is time for them to spawn) and found that they had spawned. The crew found that prior to the arrival of the adults, the smolts had left, swimming with the current down the four foot weir, through the effluent channel and earthen channel, straight to the Grand Calumet River and eventually Lake Michigan. "We expect to see these same fish in three to five years, when it is their time to spawn," Early said.
The treatment plant has a man-made earthen channel that empties into a combined sewer overflow reservoir, which directs the plant's treated effluent to the Grand Calumet River. The river then leads the water several miles to Lake Michigan.
The channel supports migrating salmon, rainbow trout, sunfish, minnows and other aquatic life. As a result of the fish spawning in this area, they have become a food source for a variety of animal life, including deer, beavers and foxes, as well as ducks, swans, geese, kingfishers, blue heron and white egets.
Sensational Ecological System
The amount of interest in these sponges has caused a major sensation for ECSD. Specialists in environmental science, some from as far away as Kenya, have visited the treatment plant to see the phenomena for themselves.
Baranyai is convinced that the UV disinfection system has something to do with the growth of this ecosystem. "The sponges are only located in the water after ultraviolet disinfection," he said. "It's apparent the UV is killing the bacteria and allowing this environment to thrive," he said. "Therefore, I believe there is a direct relationship in using UV light as a mechanism of destruction of bacteria in the wastewater and the growth of the sponges."
An added benefit of the sponges is that they are serving as a fourth means of filtration for the District, further purifying the water in the effluent channel before it is discharged into the receiving stream and, ultimately, Lake Michigan.
Sponges are highly efficient filter-feeding animals capable of removing a wide range of materials, including algae and bacteria from the water. Just a small piece of some species can filter over 30 gallons of water per day. "The sponges here at ECSD are probably helping us to filter more than 4 million gpd," said Baranyai.
Also, these sponges will die off, clogged with algae if the water quality deteriorates. The fact that they are thriving proves that East Chicago's water outflow is clean and pristine.
Secret of Success
Since this ecological system is the result of contributions from many sources in to improve the environment, Baranyai gives credit where credit is due. He said that this phenomenon is a success story for the Clean Water Act, which imposed regulations that required ECSD to upgrade and improve its facility. "We've done what the Clean Water Act was designed to do. This speaks of the success of when industry and government work together to achieve a common goal."
Also credited by Baranyai are the industries that surround the treatment plant, as well as the community. "Years ago the quality of the environment was lower, but the industries have worked to improve it as well. Also, the citizens of East Chicago have participated in recycling programs and there is education for the general public."
Baranyai also deserves credit. He used treated waste to plant sunflowers and a pumpkin patch, which flourished with pumpkins that were sent to local schools in time for Halloween.
"We don't want this to be East Chicago's best kept secret," Early said. "We want this to be available [to other plants] around the world. We need partnership and funding in this investigation so that we can advance this project further and faster."
"This project has the potential for the whole world to benefit," John Kundrat, managing director of the Aquatic Resource Center said. "After all, water is the most valuable resource we have."
About the Author:
Jeanne Spacek is the WEM associate editor.