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Home My WebLink AboutCOM 0577.000 1998-2000 RECEIVED nme.. ~~~By-- -~-M--°-- County •lrOUnCli November 23, 1999 ss,o,e Mr. Jiro A. Sumada Chief Engineer Department of Public Works County of Hawaii 25 Aupuni Street Hilo, Hawaii 96720 Dear Mr. Shimoda: Subject: Papaikou Wastewater Treatment Plant Operation and Maintenance Inspection Our annual operation and maintenance inspection report of the subject facility is attached far your use. The facility is given a "Conditional Acceptable" rating for the following reasons: 1. The chlorine contact tank contained a 6 to 12-inch layer of sludge on the bottom of the tank. Sludge carryover with the final effluent can occur during peak flows or when the sludge denitrifies; 2. The chlorine alarm was tested during the inspection and found to be inoperable; and 3. The headworks ventilation fan was inoperable. For liability and personnel safety, the ventilation system should be inspected and repaired. Other deficiencies noted during the inspection are included in the attached report. Please submit within 45 days after receipt of this letter a written corrective action plan addressing the cited deficiencies. The plan should also include a reasonable time schedule for implementation of your actions. Should you have any questions, please call Ken Muranaka of our Wastewater Branch at telephone no. 586-4294. Sincerely, '~0. THOMAS E. ARIZUMI, P.E. Chief, Environmental Management Division Comm. No. Attachment S E w F71e No. c: EPA, Region I% (Attn: Mr. Dan Meer, Iw/report) 1~ TDi QV,/ P ~ , County Council Public Worke Chairperson (wlreport) DOH, Clean Weter Branch (w/report) Ref. Date 'g ,'9~ OPERATION AND MAINTENANCE INSPECTION REPORT INTRODUCTION Facility: Papaikou Wastewater Treatment Plant Date(s) of Inspection: September 14, 1999 Inspector(s): K. Muranaka Facility Representative(s)/Job Title: Lyle Hirota - WWTP Superintendent Andy Narido Sr. - WWTP Supervisor (T/A) Robert Loeffler - WWTP Operator II BACKGROUND 1. Current status of deficiencies cited in previous inspection reports: No major deficiencies were noted during the 1998 O&M inspection and the facility was given a general rating of "Acceptable". 2. NPDES Permit Status: Permit Expiration Date: January 22, 2004 Comments: The current NPDES permit issued on December 22, 1998 became effective on January 22, 1999. 3. Enforcement Action: The facility is not under any current enforcement action by DOH. 4. Capacity Analysis: Average flow: 0.105 MGD (For the period 07/98 to 06/99) Design Flow: 0.350 MGD; Percent of design capacity: 30$ Previous year's comparison: An increase of 0.018 MGD in plant flows occurred as compared to the previous year's average flow of 0.087 MGD. The increased flow was due to the construction of an extension of the Paukaa Collection System. A total of 105 new sewer connections were reported. 5. influent/Effluent Data Analysis: Based on monthly averages. a. Influent BODS 160 mg/1 (composite) b. Effluent BODS 2.3 mg/1 (composite) c. Influent TSS 173 mg/1 (composite) d. Effluent TSS 2.7 mg/1 (composite) e. pH (min) 6.30 (grab) f. pH (max) 6.90 (grab) g. Chlorine residual: 0.61 ug/1 (grab) 6. Modifications/Additions - Planned/Present Construction Status: The 8-inch supernatant sidestream return line was relocated from the primary influent channel at the headworks to the secondary backup channel in January 1999. This modification allows sidestream return flows to be channeled back into the plant downstream of the influent sampling station. CURRENT INSPECTION 1. Maintenance: Check either: No. of: Preventive Maintenance: x Current Backlogged Corrective Maintenance: x Satisfactory Excessive Major (or all) items requiring repair/replacement: None. 2. Reuse: The facility has a DOH approved effluent irrigation plan: Yes No x Not applicable 3. NPDES or Chapter 62 violations (effluent limitations, spills, etc.) None. 4. Visual quality of effluent on date of inspection (inspectors judgment): The effluent was noted to be clear on the date of the inspection. 5. Facility~s Present Deficiencies: a. The headworks ventilation system was inoperable. operations personnel keep the doors and window louvers open during the day for ventilation purposes. For safety and liability O&M Report Form (12/93) 2 considerations, the ventilation system should be made operable; b. The fire extinguisher in the Control Building was noted to be completely discharged. Monthly visual inspections of the pressure gage for all fire extinguishers in the plant should be performed in addition to the annual testing and inspection by Hilo Fire Extinguishers Co.; c. During the inspection, the chlorine alarm was tested with powdered chlorine (pittchlor) and found to be inoperable. Operators normally perform monthly PM of the unit by activating the test switch or by unplugging the power cord to the unit. This tests the alarm bell but not the probe. For personnel safety, regular testing with a pittchlor or chlorine solution and proper cleaning of the electrodes must be incorporated. A written standard method for cleaning the electrodes should be provided for all treatment facilities countywide; and d. A 6 to 12-inch thick sludge layer was found on the bottom of the Chlorine Contact Tank during the inspection. Sludge carryover with the final effluent can occur when the sludge denitrifies and/or during peak flows. The tank needs to be vacuumed on a more frequent basis. In addition, the sludge blanket should be checked at least weekly. SUMMARY i. General Rating: ACCEPTABLE X CONDITIONAL ACCEPTANCE UNACCEPTABLE Explanation: The facility was being operated and maintained satisfactorily with the exception of the above deficiencies. 2. General Comments/Recommendations: The following items are recommended for plant improvement: a. The aeration tanks have not been rotated since plant startup. It is recommended that Aeration Tank ,}1 be drained, cleaned, inspected, and repaired as necessary. The mixed liquor from Aeration Tank #2 should be pumped into Aeration Tank ;1 for startup. Tank #`2 should then be taken down, inspected and repaired as necessary. Residual lime that settles on the bottom of Tank #2 can be collected, washed, and reused; 0&M Report Form (12/93) 3 b. The 1995 O&M inspection report noted that the standby aeration tank was to be used as a flow equalization basin. Storm flows in excess of 0.6 MGD would be routed to the standby aeration tank via a slotted gate. Storage is currently unavailable with Aeration Tank #1 being full of rainwater as noted in item #2a above. The slotted gate was moved to the discharge channel. It is recommended that the gate be relocated back to the influent channel; and c. Heavy algal growth was noted on the effluent weir of Final Clarifier #2. The algae growth should be cleaned periodically. O&M Report Form (12/93) 4