Company Reaches Settlement Over Chlorine Discharge Violations In Connecticut

Operations Management International Inc. (OMI), which operates wastewater treatment plants in New Haven and Norwalk, agreed to pay $2 million to settle alleged chlorine discharge violations.

Kevin J. O'Connor, U.S. Attorney for the District of Connecticut, announced on Feb. 8 that OMI and the U.S. Attorney's Office have entered into a deferred prosecution agreement relating to the Office's investigation of alleged permit violations.

In response to the investigation, OMI has to date made substantial changes to operations and environmental oversight, described more fully in the agreement, including implementing a compliance effort nationwide and at the facilities in Connecticut at cost of more than $6 million, officials said. OMI has cooperated with the investigation and will continue to cooperate. In addition, OMI will contribute $2 million to targeted projects:

  • $1 million to the Greater New Haven Water Pollution Authority to pay for plant upgrades and, if those funds exceed proposed repairs, provide the remainder to two public interest organizations, Long Island Sound Fund and Long Island Sound Study.
  • $1 million to assist in the funding of an endowed chair of environmental studies at the U.S. Coast Guard Academy, located in New London, Conn.

"We're pleased that this investigation has prompted OMI to reform its compliance efforts so that these violations do not happen again, in Connecticut and elsewhere," O'Connor stated.

The agreement expires 24 months from Feb. 8. If, at that time, OMI is in full compliance with all of its obligations under the agreement, the government will seek dismissal of the charges against the company and will not prosecute OMI for the conduct alleged in the agreement.

OMI is engaged in the business of providing wastewater treatment services and operates wastewater treatment plants at various locations around the country, typically under contract with the municipalities who own those facilities. Since January 1999, OMI has operated the wastewater treatment facility that is owned by the city of New Haven, managed by the New Haven Water Pollution Control Authority (WPCA), under contract with the city. At all relevant times since OMI began performance of this contract there has been in effect a permit issued by the Connecticut Department of Environmental Protection (DEP) under the Clean Water Act (CWA) to the New Haven WPCA which, among other things, imposes certain conditions on the quality of the effluent discharged from the Facility to the receiving waters in New Haven Harbor, officials said. As the contract operator of the facility, OMI was obligated to comply with those effluent limitations imposed by the permit.

Among other things, the permit has contained an effluent limitation for residual chlorine, which provides that chlorine in the effluent, as reflected in four "grab" samples to be taken during the day, shall not exceed 1.5 milligrams per liter (mg/l) nor be lower than 0.2 mg/l. The OMI operators typically collected the chlorine grab samples four times each day. Before bringing each sample to OMI's laboratory for analysis, the operators conducted a chlorine field test using a Hach test kit. These field tests were not required by the permit but enabled the operators to make adjustments to the plant's manual chlorine feed system. After completing the field test and adjusting the chlorine addition, the operator brought the sample to OMI's on-site laboratory. There, OMI laboratory technicians analyzed the sample and recorded the results in a chlorine bench book. Each day, the bench book data was summarized on a laboratory data sheet. Those sheets, along with the bench books, were reviewed by the laboratory manager who entered the data into the "Ops 10" computerized data system. Other OMI managers used the data in the Ops 10 system to prepare MORs and DMRs.

Because of the variability of the wastewater and the limitations of the manual chlorine feed system, the New Haven plant did not always operate within the residual chlorine limits. As a consequence, sometimes, when the operators collected the four daily samples identified above and undertook a process check of chlorine level, potential chlorine exceedances were detected by the operators. On these occasions, the operators discarded the sample, adjusted the chlorine, and then collected a new sample. At least one person in OMI management at the New Haven plant was aware of this practice.

Chlorine samplings that were outside the permit range that were not detected by the operators' field tests were caught by the more sensitive analyses performed in OMI's on-site laboratory. On 15 occasions between July 26, 2000, and Sept. 18, 2002, OMI's laboratory technicians identified a sample outside permit range. The laboratory technicians recorded the results of the sample in the laboratory chlorine bench book, but not on the laboratory data sheet, and instructed the OMI operators to collect an additional sample. At least one member of OMI management at the New Haven facility was aware of this practice, including that the samples outside the permit range were ultimately not entered in the Ops 10 system and not reported on the relevant MORs and DMRs.

Prior to Dec. 13, 2001, OMI personnel at the New Haven facility used an automatic sampling device known as an "autosampler" to gather final effluent composite samples for analyses to ascertain compliance with the relevant effluent limitations. In September of 2001, the equipment began not to function properly. As a result the operators frequently augmented the sample with additional effluent before bringing it to the laboratory for analysis, a practice known by at least one member of OMI management at the New Haven facility.

By Dec. 13, 2001, OMI took the autosampler off-line and replaced it with manual grab sampling. This grab sampling program called for taking eight flow-proportional samples per day. OMI management at the New Haven facility were aware of the permit requirements, including that manual sampling was permitted, but did not follow the permit requirement that the samples be taken at intervals no more than 60 minutes apart. The manual grab sampling program continued until approximately June 6, 2002, when the autosampler was repaired at a cost of $750 and put back on-line.

Pursuant to its 2000 contract with the city of Norwalk, OMI has been responsible for operating the Norwalk wastewater treatment plant since June 2000. At all relevant times, OMI operated the plant to maximize nitrogen removal by maintaining a higher than normal level of sludge in the plant clarifiers. The clarifiers are large settling tanks in which solids sink to the bottom and are collected for disposal while effluent is designed to flow over the top of the clarifiers through the process for disinfection and discharge. However, higher than normal levels of sludge can cause disruptions in the clarifiers, interfere with settling and cause solids to wash into the discharge. Between June 2000 and October 2002, higher than normal levels of sludge caused the clarifiers to overflow and resulted in several solid washouts. OMI was aware of the washouts but did not report them to DEP in the manner required by the DEP discharge permit issued to the city of Norwalk.

Under the terms of the deferred prosecution agreement, OMI has accepted responsibility for the conduct at the New Haven and Norwalk facilities and has taken substantial measures to prevent such conduct from occurring in the future, is cooperating in any continuing investigation and has consented to the payment of $2 million, as noted above.

The deferred prosecution agreement can be viewed at

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