Field Office Compliance - Assistance

Assistance ID - 114397
Osceola Water Works - 310338248
2320 WEST CLAY STREET Osceola, IA 50213
Clarke County

FO 5

Report
File Name File Type File Date Note
Comments
2/25/2021 Normally manganese is contained in bottom sediments as insoluble particulate oxides. During warm summer months, a number of things can happen to reduce the dissolved oxygen (DO) content in the water near these bottom sediments. A lack of rainfall with inadequate mixing of fresh and stagnant water, increased algae growth, deterioration of organic matter as the water warms up, and low wind conditions, can all contribute to depletion of DO levels. If a reservoir becomes stratified as a function of temperature, the bottom layer will be very low in DO. This leads to the development of anaerobic conditions in the deeper portions of the lake bottom sediments. Manganese is converted from oxide forms that are insoluble through bacterial action to manganese ions (Mn++) which are very soluble and now leach out of the sediments. A manganese concentration of just 0.5 mg/L is ten times the drinking water standard and can cause significant color and staining problems. One of the cheapest methods of manganese removal, chlorine oxidation, often cannot be used on such water sources due to the formation of trihalomethanes (THMs) and haloacetic acid (HAA) from the dissolved organic carbon in the water. Under anoxic conditions (i.e. waters where oxygen is absent), increased release of iron and manganese from bottom sediments may result in elevated concentrations of these metals in the water. High concentrations of iron and manganese can impair the use of water, as the metals are precipitated upon re-aeration during the water treatment process. This is typically where the manganese problems begin during stratification. Concentrations of phosphorus, ammonia, iron and manganese are greatly influenced by the presence of oxygen in lake water and sediments. Ammonia is a breakdown product of proteins. When little or no oxygen is present at the sediment-water interface, concentrations of ammonia can be quite high. Ammonia is toxic and represents a further threat to aquatic life. Sediments in lakes can contain a lot of iron, manganese and phosphorus. These can be released in large quantities from the bottom of the lake when oxygen levels are very low. Iron and manganese can cause treatment problems in water treatment plants. Phosphorus released in the water fuels yet more plant growth. Bottom sediments can provide a significant source of phosphorus to prairie lakes. Phosphorus bound to the bottom sediments is released to the overlying waters when the water overlying the bottom sediments in a lake become anoxic. During the summer, most deep lakes experience a temperature-density gradient in the lake profile from warmer surface (epilimnion) waters and cooler bottom (hypolimnion) waters. The process of establishing a density gradient in a lake, either in winter or summer, can be beneficial in slowing down manganese is termed stratification. Phosphorus-rich hypolimnetic water is isolated at the bottom of the lake if the water is anoxic and a temperature-density gradient exists. However, when the temperature gradient disappears during the spring and fall, the entire water column in the lake mixes or 'turns over'. This allows the phosphorus-rich bottom water to circulate to the lake surface where the combination of available nutrients and sunlight facilitates algal growth. An additional source of phosphorus to lake water is the resuspension of sediments. Sediments can release phosphorus and manganese when resuspended into the water column of a lake by wind action. JANET GASTINEAU
8/20/2020 Gastineau, Janet <janet.gastineau@dnr.iowa.gov> 12:43 PM (0 minutes ago) to Keith, Bob, Taroon, Diane, Thaddeus, Anne, Ted Osceola appears to be through the worst of their recent upset. CFE is down to 0.3 NTU and IFEs are performing fairly equally without regard to the age of the GAC. Manganese levels are down and consistent through the treatment train. Brandon will be submitting a partial MOR for August so I can get the second TTV issued (95% CFE rule) so they can get the PN issued for both violations with their September 1 bill mailouts. SIRWA's plans are similar. When everything settles down sufficiently, the operator will submit an as-built application for the permanganate feed so it's on the books as a permanent feed that will likely be used seasonally. Thanks to everyone who put their heads together on this one:) JANET GASTINEAU
8/18/2020 On Mon, Aug 17, 2020 at 4:08 PM Gastineau, Janet <janet.gastineau@dnr.iowa.gov> wrote: Everything was sort of settling down over the weekend. CFE was down to 0.28 ntu, but then they saw another bloom off shore and treated it with sodium percarbonate and manganese came back up to over 1 mg/L. CFE was up to around 0.39 ntu when I talked to him around 3 pm. Upflow clarifiers and IFEs turbidity looks pretty good, but coming out of the two clearwell and the CFE compliance point are back up today. They continue to treat with permanganate and plan to get a bigger pump hoping to increase the dose even further. They are also only treating with chlorine dioxide on the clarifier effluent (with the chlorine portion of the generator higher than usual). Please, if anyone has any suggestions, they're welcome. The operator is going to ask for some help from their engineer on a better location for permanganate feed. A better location for the CFE compliance point (currently on the suction side of HSP) is unlikely without construction. Each filter effluent line runs separately into the two clear wells and although there is a line between the clear wells and GSR, when the transfer pumps kick on they cause turbidity spikes. JANET GASTINEAU
8/13/2020 Gastineau, Janet <janet.gastineau@dnr.iowa.gov> 8:37 AM (0 minutes ago) to Keith, Bob, Taroon, Diane, Thaddeus, Anne, Ted The operator and I continue to be in touch daily and sometimes more frequently. This morning I received the results of cyanobacteria testing of raw and finished samples. These were collected again because they switched from the lower intake back to the upper intake, which had higher counts. The good news is, Cyanobacteria is down from 95,600 cells/ml to 41,600 cells/ml in the raw water and no detect for microcystins in the raw or finished sample collected 8/11/2020. The bad news is, the finished water only went from 269 cells/mL to 220 cells/mL in the finished water sample. As of last night, CFE was down to 1.11 NTU, which was pretty consistent with the values earlier in the day. They did some double backwashing of the filters over the last couple of days in hopes of removing some of the manganese that went through the treatment process when the lower intake was in use. It seemed to have helped marginally, but since they use partially treated water from their clear wells to backwash, it wasn't the magic bullet they hoped for. IFEs are pretty good though, between 0.19 and 0.38 NTU last night. Manganese is getting oxidized in the clarifier, but still slightly higher in the clear well effluent. Because there are basically two "sides" to the WTP, they have been trying different things on one side and something else on the other to see what is most effective; Chemsult continues to work closely with them through jar testing and adjustments. One thing that happened that I thought was interesting was they switched out the 1720 on the CFE with one of their TU5300 from another location. They discovered the 1720 was not lining up with their benchtop meter, which is a TU5200; the inline instrument was higher by over 0.4 NTU. Andy from Onsite Service Solutions was on site and helped them and said sometimes components on the interior on the 1720, if they get dirty enough, can reflect color and measure it as turbidity. Furthermore, turbidity went from 1.8 NTU measured on the 1720 to 1.5 NTU measured on the TU5300! Operators continue to work very hard on the problem. With this upset going on, they've also had a tower out for maintenance and had a main break! I hope to get the TTV issued before the end of the week. When the dust settles I would like to see them consider a permanent permanganate feed and relocation of the CFE off the suction side of the HSPs (which I wish they would have done over two years ago when they had manganese problems. A second reservoir is also in their future! JANET GASTINEAU
8/11/2020 Gastineau, Janet <janet.gastineau@dnr.iowa.gov> 11:48 AM (1 hour ago) to Keith, Bob, Taroon, Diane, Thaddeus, Anne Osceola continues to struggle. The installed the permanganate and moved the ClO2 injection post clarification with no noticeable success. They just can't meet the oxidation demand that the manganese is putting on the treatment process. Tim with chemsult thinks it's some other organic demand in addition to the high manganese. Later yesterday afternoon they switched back to the upper intake because it is harder to clarify but less oxidation demand from something else. They are continuing to feed permanganate and the coagulant feed was up to 105 ppm (usually around 82 ppm). They tried slowing flow and wasting from four filters with no luck. They exceeded 1.49 NTU yesterday evening--1.62 NTU. However, at 1.5 MG GSR it's going to take a while for the water in the reservoir to get pumped to the system and replaced with the currently treated water. They provided data showing the turbidity is due to manganese precipitation. They continued to treat water till about 11:30 last night and turbidity leveled off at 1.9 NTU. This morning CFE is 1.8 NTU and IFEs are between 0.4 and 0.5 NTU, which is fairly consistent with what they were last night around 10:00 pm. They only had about 1/10" of rain yesterday. I asked them to take more microcystin samples to DMWW, which they did this morning. I asked them to take another round when they think they've turned the GSR over from finished water from the lower intake to finished water from the upper intake (which had significantly higher cyanobacterial counts than the lower intake). Mn out of clarifiers is still 0.05 mg/L and higher out of the clearwell. CFE was 1.8 NTU at 10:30. Attributing turbidity to Mn, at this time I'm planning to issue a TTV with a Tier 2 (30 day public notice) like we did in March 2018. I will follow up with another TTV when I receive the August MOR demonstrating the percent of turbidity measurements that were less than 0.3 NTU. On Mon, Aug 10, 2020 at 8:17 AM Gastineau, Janet <janet.gastineau@dnr.iowa.gov> wrote: I wish I had better news. I talked to Brandon from Osceola a few times this weekend as his situation continued to decline. Clarifiers are doing fine and IFE on both sides is holding in the high teens (0.17, 0.18), but the CFE has been as high as 1.47 NTU due to manganese precipitating in the GSR. They tried to slow flow through one side of the WTP to see if that helped and it really didn't. The turbidity from the clear wells is pretty high also (1.1, 1.2 ntu). Finished manganese is 0.08 mg/L, but they are starting to get some complaints of colored water in the DS. I suggested they take some DS samples for Mn just in case and provided him the FAQ/fact sheet for some talking points. They are going to try injecting permanganate this morning. There is already an injection point on the raw water line before it splits to the two sides of the WTP. They are also going to move the ClO2 to the clarifier effluent. We talked about not doing too much at once so they can determine which was successful, which he agreed because they don't know if it was the increased coagulant or switching to the lower intake that turned the clarifiers around. He's getting pretty desperate! JANET GASTINEAU
8/7/2020 Gastineau, Janet <janet.gastineau@dnr.iowa.gov> 12:01 PM (0 minutes ago) to Keith, Bob, Taroon, Diane, Thaddeus, Anne Remaining on lower intake level IFE down to 0.2 NTU with older GAC filter side a little higher CFE down to 0.26 NTU Chlorite residuals began climbing, so they adjusted the CL02 generator to blend in more chlorine and less sodium chlorite, which concerned him for DBP formation, but they don't sample again until October. I'm touching base with him tomorrow or earlier if something changes. JANET GASTINEAU
8/7/2020 Gastineau, Janet <janet.gastineau@dnr.iowa.gov> Thu, Aug 6, 7:42 PM (12 hours ago) to Osceola Des Moines Register asking questions and here's what the Iowa DNR told them. ---------- Forwarded message --------- From: Moeller, Mark <mark.moeller@dnr.iowa.gov> Date: Thu, Aug 6, 2020 at 3:42 PM Subject: Re: Des Moines Register request To: McDaniel, Lori <lori.mcdaniel@dnr.iowa.gov>, Murphy, Alex <alex.murphy@dnr.iowa.gov> Cc: Mccoid, Corey <corey.mccoid@dnr.iowa.gov>, Wilken, Keith <keith.wilken@dnr.iowa.gov>, Janet Gastineau <Janet.Gastineau@dnr.iowa.gov>, Jason Marcel <jason.marcel@dnr.iowa.gov>, Ted Petersen <Ted.Petersen@dnr.iowa.gov>, Jessica Montana <jessica.montana@dnr.iowa.gov> Lori and Alex, Here is a response that can be used: The DNR has heard from one drinking water system that is being affected by the drought. The City of Casey is on a water conservation notice. DNR has reached out to the city and has had preliminary discussions on water hauling, if it becomes necessary. Concerning algae blooms, both the Osceola and Clarinda water systems are dealing with algae blooms and higher bacteria counts in their source waters, which are affecting their treatment processes. Currently, there are no detects for microcystins in their source water or finished water. DNR is working closely with both systems to monitor the situation. Alex, If Donnelle wants DNR contacts for any of these systems. Janet Gastineau is working with Osceola and Keith Wilken is working with Clarinda. I think the best contact for the City of Casey would be contacting the city. Keith can also be DNR's contact about Casey, if needed. From: Eller, Donnelle <deller@registermedia.com> Date: Thu, Aug 6, 2020 at 10:02 AM Subject: Des Moines Register request To: Murphy, Alex <alex.murphy@dnr.iowa.gov> Hi Alex, I wanted to touch base to see if DNR is hearing any problems from cities or towns that they’re struggling to have enough drinking water due to the drought. Also, it sounds like algae blooms are more likely during extreme droughts, so I thought I’d see if there were problems there as well. Thanks in advance for your help. Donnelle Eller DMRegister 515-314-6584/cell JANET GASTINEAU
8/7/2020 Gastineau, Janet <janet.gastineau@dnr.iowa.gov> Thu, Aug 6, 7:39 PM (12 hours ago) to Osceola I saw the results; if DMWW 25,000 cells it gets their attention and at 50,000 cells they start to worry. It really is amazing that there were no toxins at the levels in the raw water. Your GAC must be doing all it can! Osceola Upper Intake: 95,600 cells/mL – cyanobacteria (Anabaena, Pseudanabaena, Aphanizomenon) Lower Intake: 64, 800 cells/mL – cyanobacteria(Anabaena, Pseudanabaena, Aphanizomenon) Finished: 269 cells/mL - cyanobacteria(Anabaena, Pseudanabaena, Aphanizomenon) Clarinda 1000-1800 cyanobacteria in two of the samples (Microcystis) JANET GASTINEAU
8/7/2020 Gastineau, Janet <janet.gastineau@dnr.iowa.gov> Thu, Aug 6, 11:07 AM (21 hours ago) to Bob, Anne, Diane, Thad, Taroon, Keith I spoke with the operator at osceola. They switched to the lower intake which has higher manganese and is putting a greater demand on their chlorine dioxide and the chlorine that they add in the two smaller clear wells. Their IFE are down to less than .3 ntu. The side with the newer GAC is down to about .2 compared to .28 on the side with the older GAC. Finished turbidity is around .33 NTU. At this point they’re not sure which solve the problem, switching to the lower intake or increasing the permanganate. They have been treating the lake alternating weeks applying copper sulfate and sodium percarbonate. They do have two solar bees in the lake. He is more comfortable with current status but still feels like they’re not out of the woods. The lower level did have less cyanobacteria in it by about a third compared to the upper intake level. He will probably do more Cyanobacteria sampling to determine when he can return to the upper intake. JANET GASTINEAU
8/5/2020 By 8/4 IFE were higher and chemsult working on jar testing lower intake, which has lower turbidity but higher iron/manganese. Discussed CFE and results of CFE >0.349, TT, PN. JANET GASTINEAU
8/5/2020 Upset filters due to algae. Looking for TA. I met with WSE/FO4, who is working with Clarinda in a similar situation; it was decided to have samples submitted to DMWW for microcystin analysis. Jeff Mitchell said he would also do some speciation on the samples. Brandon submitted upper and lower intake raw samples and finished sample. JANET GASTINEAU
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