City of Red Oak Wastewater Department
W 2nd Ave, Red Oak, IA
Mailing address: PO Box 475, Red Oak IA 51566
(712)-623-6508 answereing machine or (712)-623-6510 City Hall
After Hours Sewer Backups-(712)-623-5107
||Asst. Wastewater Superintendent
|| Wastewater Laborer
7:00 to 4:00 Monday thru Friday
Our Wastewater Department currently has one member with a Grade III Wastewater Certification and one member with a Grade II Wastewater and Collection System Certification. We have two members with a Commercial Pesticide Applicator license for spraying mosquitoes and one member with a Commercial Pesticide Applicator license for spraying weeds.
The Red Oak wastewater plant is a Grade III trickling filter treatment facility. The plant is designed to treat an average dry weather flow of 1.2 million gallons/day (MGD), an average wet weather flow of 2.2 MGD, and a maximum flow of 4.9 MGD. The design biochemical ozygen demand (BOD) load is 1895 lbs./day.
All wastewater comes into a pump station where it goes through a bar screen to remove debris that is too big to go through the pumps. It is pumped to the grit removal system and then the water is divided between two primary clarifiers. Sludge settles and flows to a sludge thickener for futher settling. Scum, which is made up mostly of household grease, floats to the top and is skimmed off and pumped to the digester.
Flow from the primary clarifiers is pumped to the trickling filter for removal of BOD. It then is pumped to the packed towers which aid in the removal of ammonia nitrogen. The water then flows to the two final clarifiers. Any sludge will settle and flow to the sludge thickener. The water that overflows the final clarifiers is then discharged to the East Nishnabotna River.
The wastewater, influent and effluent, is tested for BOD, total suspended solids, ammonia nitrogen, settleable solids, pH, and temperature. These tests are performed in the IaDNR certified lab at the treatment plant. Our lab is certified every two years by a member of the University of Iowa Hygienic Laboratory. The effluent is also tested for copper, toxicity, and starting in the spring of 2011, E. coli. These three tests are sent to outside laboratories. Limits for all parameters are outlined in the NPDES permit which is issued by the IA Department of Natural Resources who also inspects the plant yearly. A monthly operating report (MOR) is sent to IaDNR which includes plant flow, recirculation through the plant, all test results and how many pounds of BOD and TSS in the influent and effluent and ammonia nitrogen and copper in the effluent.
We also monitor and test any major contributing industries. This is also outlined in the NPDES permit.
Sludge from the thickener is pumped to the digester where heat and bacteria decompose the solids to futher process it for land application. The digester is tested for pH, acidity, alkalinity and the temperature is also monitored. Solids tests are done on the raw and digested sludge to make sure the reduction of volatile solids is adequate for the land application. Sludge is land applied at the City owned airport in the spring and fall. During application a sample is tested for arsenic, cadmium, chromium, copper, lead, mercury, molybdenum, nickel, selenium, and zinc of which there is a maximum cumulative loading of lbs/acre. Sludge can only be applied up to 2 tons/acre dry weight per year. A detailed sludge report is sent to IaDNR and EPA yearly.
Some helpful hints for the household would be not to put grease down the drain (sewer backups and clogged drains can be caused by grease buildup) and if you smell sewer gas and have a floor drain, put some water in the drain. Especially during the winter the water will evaporate from the trap. It's alsoagainst City Code to have sump pumps discharge to the sewer system.
Our department takes care of the collection system by using a jet truck that also has a vacuum unit on it.
The Wastewater department also does the maintenance of the levee which is inspected yearly by the Army Corp. of Engineers and the old City Landfill which is inspected yearly by EPA.