What Are Chloramines?

Chloramines are a mixture of chlorine and a small amount of ammonia.  While obviously toxic at high levels, neither poses health concerns to humans at the levels used for drinking water disinfection.  Visit the Environmental Protection Agency website for additional information regarding Chloramines.

There are some within the community that have shown concern with the use of Chloramines for water disinfection.  From the extensive research the HBPW and it's hired consultants have done, as well as the research done by the United States EPA, the HBPW agreed that the use of chloramines was the best option for disinfection.  The use of Chloramines has become one of the most common forms of water disinfection in the United States.  Chloramines, the monochloramine form in particular, has been used as a disinfectant since the 1930's.

Because the chloramine residual is more stable and lasts longer than free chlorine, it provides better protection against bacterial regrowth in systems with large storage tanks or piping systems, buildings taller than 10 stories, and dead-end water mains.  One case study done by the National Center for Infectious Diseases stated that, "Increasing use of monochloramine in water supplies throughout the United States may reduce Legionella transmission and incidence of Legionnaires' disease" (Read the full article Emerging Infectious Diseases, or visit www.cdc.gov/eid).

In 2000, the American Water Works Association published a similar journal article that studied hospitals where outbreaks of Legionnaires' disease occurred.  They found that hospitals supplied with drinking water containing free chlorine were 10.2x more likely to have reported an outbreak of Legionnaires' disease than hospitals that used water with monochloramines.  Read the full article Legionnaires.

Additional Information

Press Release send August 28, 2015

Letter from HBPW Director of Operations

Letter to the Editor - Hannibal Courier Post sent November 16, 2015

MoDNR Response Letter sent November 23, 2015

GAC Memo presented to HBPW Board February 16, 2016

April 5, 2017

On April 4, 2017, the citizens of Hannibal voted to remove the use of ammonia as part of the city’s disinfection system by a vote of 1,259 to 894.  The proposition called for the Hannibal Code of Ordinances to be amended to include the ordinance prohibiting the use of ammonia in the public drinking water system within 90 days of approval by City Council.

The HBPW Board has solicited a proposal from Black & Veatch Engineers to begin the process of studies, reports, and designs required to eliminate the use of ammonia in our drinking water.   The proposal is currently being written.

April 19, 2017

The HBPW Board solicited a proposal from Black & Veatch Engineers to begin the process of studies, reports, and designs required to eliminate the use of ammonia in the drinking water.  This is the Board’s first action item required to come into compliance with the results of the Proposition 1 referendum on April 4, 2017.  During the April 18th board meeting, the HBPW Board received the first draft proposal from Black & Veatch.  The Board will review the proposal and convene next month for a special board meeting to discuss changes.

Memo from Bob Stevenson on April 18, 2017

May 9, 2017

The HBPW Board held a special meeting on Monday, May 8, 2017 to discuss and approve the Chloramine Replacement Alternative Evaluation proposal submitted by Black & Veatch Engineers.  Several changes were made to the first draft proposal given to the HBPW Board members last month, and the final document was approved. Read the Approved Proposal.

Part of B&V's scope of work will help identify target treatment goals for the 90 day referendum period, as well as long term target goals and objectives for the project, while remaining compliant to all regulatory requirements.  It is the HBPW's responsibility to remain compliant with both the City referendum and current drinking water standards throughout the entirety of the project.

May 25, 2017

The Hannibal Board of Public Works Board of Directors received the Chloramine Replacement Alternative Evaluation:  Implementation Strategy from Black & Veatch Engineers.  This report identifies target treatment goals, and details concerning the project’s approach, constraints, and delivery.

May 31, 2017

Black & Veatch Engineers met with the Missouri Department of Natural Resources to discuss the Discontinuance of chloramines in Hannibal's water treatment disinfection system.  In attendance were several Black & Veatch members, several members of MoDNR and State of Missouri, and HBPW’s Utility and Construction Engineer, Mathew Munzlinger.

June 7, 2017

Bob Stevenson, General Manager for the HBPW, submitted a projects report to the Board.

July 25, 2017

On July 25th the HBPW Board Members received a copy of Black & Veatch Engineers Initial Findings Report over the Chloramine Replacement Alternative Evaluation that was proposed to the Board of Directors in April 2017 and approved in May 2017.

"[This 64-page report] summarizes findings from an initial screening of potential solutions to enable compliance with MCLs for TTHMs and HAA5s once the plant begins operating with free chlorine in place of chloramines.  The initial screening consisted of a comprehensive review of the City's treatment alternatives, distribution system modifications, and potential source water alternatives." 

August 9, 2017

Hannibal Board of Public Works staff, Calgon Carbon Corporation and Black and Veatch Engineers installed a small scale Granular Activated Carbon (G.A.C.) system at Hannibal’s Water Treatment Plant.  This unit has four vessels which mimic four different G.A.C. treatment scenarios. The data from these four vessels will guide us in determining which process will be most advantageous in meeting future regulations without the use of Monochloramine disinfection.  This DNR approved Pilot Project will extend for up to six months and plant personnel will monitor numerous parameters at least every 3 hours throughout the length of the Pilot Project.

The four vessel tests include:

1st vessel - A single G.A.C. vessel

2nd vessel - Two G.A.C. vessels in series

3rd vessel - Vessel mimicking our current filter construction with a G.A.C. cap

4th vessel – Vessel demonstrating

For photos of the pilot study, go to the Hannibal Board of Public Work's Facebook page.

October 9, 2017

The HBPW received data from the G.A.C. pilot study that was installed at Hannibal's Water Treatment Plant in August 2017.

November 15, 2017

HBPW General Manager, Bob Stevenson, gave an update on the Chloramine Replacement Project to the utility Board during the monthly board meeting, detailing Black and Veatch Engineers progress since October 2017.

The GAC pilot testing continues at the Water Treatment Plant.  Accumulated data is presented in the two links below.  These graphs were prepared by Black & Veatch of preliminary TOC (total organic carbon) data collected from the pilot study.  The trend lines the utility is paying attention to are represented by Columns 3 and 4. When the Column output TOCs matches or equals the Clearwell TOC levels it is an indication the GAC must be replaced.  Prior to the start of this study, the utility expected the batch of GAC to last up to 12 months before replacement was required.  The below charts indicate that the GAC is exhausted after only 120 days.

Column 3 Results         Column 4 Results

December 19, 2017

Black & Veatch presented the following presentation to the HBPW Board of Directors during the December board meeting.

HBPW Preliminary Design Presentation

They also presented a draft of the Chloramine Replacement Evaluation to the Board of Directors.  The HBPW will select which alternative to move forward with, and once the alternative is selected, Black & Veatch will modify the report to include the recommendation and submit a sealed final version to the Missouri Department of Natural Resources.  Click the link below to download a PDF copy of the report.

DRAFT - Chloramine Replacement Evaluation

January 17, 2018

WM Financial Strategies

The HBPW Board was presented a proposal from Joy Howard from WM Financial Strategies during January’s board meeting.  This proposal will assist the HBPW with obtaining financing for capital improvements at the Water Treatment Plant.  Board members will make their final decision during March’s board meeting as to what water treatment option the HBPW Water Treatment Plant will transition to in the near future.  Mrs. Howard has assisted the HBPW in the past with financing all funds, including Electric generator project, the Water SRF (State Revolving Fund) financing, and the Sewer bonds.

During the same meeting, Board members spent a large portion of their time discussing design, pricing proposals, and the pros and cons of Reverse Osmosis (RO) and Granular Activated Carbon (GAC) treatment options.  After much discussion regarding design, pricing proposals, and the pros and cons of each option the Board decided to table the vote until the regular February Board meeting to do additional research of each option presented.

Utility Financial Solutions, LLC

The HBPW will renew a Water Cost of Service Study with Utility Financial Solutions that will include the cost of service study, five year financial projection and development of financial targets, and a one year rate design.  The study will give the utility a plan on what rates should be set at over the course of 3-5 years to cover cost of expenses.  The HBPW typically performs a cost of service study for each utility (electric, water, sewer) every five (5) years.

To view the proposal from UFS, click Hannibal Water Cost of Service Engagement Letter.

February 20, 2018

During the monthly Board of Directors meeting held on February 20, 2018, the HBPW Board made a final decision on what treatment option would be implemented at the Water Treatment Plant.  The Board of Directors voted unanimously to begin design work for a Granular Activated Carbon (GAC) filtration system.

The Board has also approved a contract with Black & Veatch to design and bid the new treatment process.  Click   to read the full contract provided by Black & Veatch.


Heath Hall, Director of Operations, presented two options for the Board of Directors on design options available once a new treatment system was chosen.  The Board unanimously voted to use the traditional Design-Bid-Build method for the project.


The below links are two cost estimate options for raising new revenue for Proposition #1 compliance.  These estimates summarize new revenues the HBPW Water Fund needs to collect to pay for the capital and operating costs associated with a new disinfection process.  Each spreadsheet also details the thought processes behind several different ways the new revenues could be assigned to the various customer classes, including the changes to meter charges and usage charges that each option would involve, and the actual percentage and dollar amount effects on the average Residential customer.

Project Cost Estimate – if 25 Year Bond

Project Cost Estimate – if 25 Year Lease

The numbers used in each estimate have been obtained through professional engineers, Black & Veatch, as well as current market pricing, and are subject to change based on final borrowing costs, operating costs, and construction costs.

March 2, 2018

Black & Veatch submitted the final Chloramine Replacement Alternative Evaluation to the Missouri Department of Natural Resources.

HBPW staff met with Black & Veatch for a design kick-off meeting to go over design alternatives of necessary improvements.  Since that meeting, Black & Veatch personnel have been working on a design memo and preliminary layouts of the improvements.

April 17, 2018

Hannibal Board of Public Works Board of Directors approved the use of Bond financing for funding the Chloramine Replacement Project.  Steps are being taken for City Council approval of necessary documentation to be included on the August 7, 2018 election ballot.