Village of Red Hook WWTP – June 2025 Sewer Report

ee C~S Delaware Engineering, D.P.C.

28 Madison Avenue Extension Albany, New York 12203

Tel: 518.452.1290 Fax: 518.452.1335

July 22, 2025

The Honorable Mayor Karen Smythe Village of Red Hook 7467 S Broadway, Red Hook, NY 12571

Subject: Village of Red Hook WWTP – June 2025 Sewer Report

Dear Mayor Smythe:

The Old Plant (outfall 1B) was placed in operation on May 28, 2025 and treatment on that side took a few weeks to fully treat the wastewater. This startup lead to discharge permit violations for total suspended solids (June 5) and settable solids (June 6). Note that even with the high effluent solids BOD, ammonia, and fecal were all incompliance for the whole month.

Since June 6, treatment on both sides has been in full compliance with the discharge limits. The effluent quality has been very clear and odorless.

The effluent flow meter on the Old Plant was re-calibrated June 20, 2025 and confirmed that the flow data recorded prior to that date was artificially high by a factor of approximately 2.

The modifications noted in the May 2025 report will be needed to continue compliance.

The following data is extracted from the DMR reports attached to this letter.

|Parameter|Units|Result Old Plant|Result New Plant|Limit| |---|---|---|---|---| |Average Day Flow|mgd|0.0196|0.0286|0.025/0.05 (1) max| |Total Suspended Solids (TSS)|mg/L|29.5|7.56|10 max| |Carbonaceous BOD5(5-Day)|mg/L|4.7|<4.0|5 max| |Total Ammonia Nitrogen (as N)|mg/L|0.644|0.735|0.98 (2) max| |UOD|mg/l|32.3|19.5|34 max| |Fecal Coliform|MPN/100|<10|<10|200 (3) max| |Dissolved Oxygen|mg/L|7.21|8.17|7 min|

Notes:

1. Outfall 1A (New Plant) has a monthly average flow limit of 50,000 gpd and outfall 1B (Old Plant) has a monthly average flow limit of 25,000 gpd.

2. The limit for Total Ammonia Nitrogen (as N) is 0.98 mg/L from June 1[st] to October 31[st] and 1.81 mg/L from November 1[st] and May 31[st] .

3. The limit for Fecal Coliform is regulated as 200 No./ 100m over a 30-Day geometric mean and 400 No./ 100m over a 7-Day geometric mean.

223 Main Street Goshen, New York 10924 845.615-9232

55 South Main Street Oneonta, New York 13820 607.432.8073

548 Broadway Monticello, New York 12701 854.791.7777

16 East Market Street Red Hook, NY 12571 518.452.1290

Delaware Engineering, D.P.C.

Please call me at 518-452-1290 if you have any questions.

Sincerely, Roberto Flores, P.E.

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