Local Residents Tour The Mesa Plant
By Nick Myers
I recently had an opportunity to tour the Greenfield Wastewater Reclamation Plant (GWRP). Before I continue, I want to point out that all opinions and views expressed in this article are my own. I have not (nor do I expect) that I will be asked to tour a Johnson Utilities (JU) facility, so any comparisons made in this article are done from my own distant observation, docket items, and live streams at the Arizona Corporation Commission.
The first thing I noticed after parking right outside the gate: NO SMELL! This is an immediate and stark contrast to simply driving down Hunt Highway within a mile or two of some of the JU facilities. Second, I walked in the administrative building and not only was I greeted with a smile, but they were expecting me and ready. Already, customer service is top notch. This is going to be a good day. I apologize for not having pictures at this point, I was busy chatting with the staff and joking around. Besides, I didn’t know how they would react to photos being taken. My background in dealing with JU has not been the friendliest or most helpful, so I didn’t want to push any boundaries. Needless to say, they were more than accommodating.
First, they described the entire flow of the plant. They even have brochures printed up to give a visual representation.
After going through each of the stages of processing shown above, and answering a lot of questions (most questions offered up by me and John Dantico), we continued on to the SCADA control room.
This is the room where the general overview of the plant can be seen and monitored. Much of the operations of the plant can be monitored electronically, and shown as a red/yellow/green indication on a computer screen. If any issues are detected, an indication is given and the operator can go check it out. This method is not foolproof, but is a highly efficient method of utilizing manpower. Sitting right next to the SCADA monitors, to the left is the e-log entry station. Any discrepancies are logged and kept for a minimum of 7 years. However, they verbally said that they have chosen to keep the records forever.
Comparing this to JU, It should be noted that JU does use SCADA, but from ACC documents and EPCOR reporting, it is inadequate for their operation. After EPCOR took control, one of their tasks was to upgrade, and repair SCADA infrastructure. Also, JU has had Notice of Violations (NOVs) written up regarding their lack of on-site logs being kept, their inability to produce any logs on sight, and their apparent falsification of logs when demanded, which occurred by someone noticing that all handwritten values were exactly on day off but identical to a different month at one point in the hearings (ACC Docket Number: WS-02987A-18-0050). It appears they cannot keep logs for 1 hour, let alone forever.
The next stop on the tour was the onsite lab.
This lab is mainly used in running daily operations of the plant. The lab is not used for legal verification of compliance, which is passed off to third party labs. Multiple samples from each section of the plant are brought into this lab daily and tested for the state of the various microorganisms (called “bugs” by the staff). This includes both the health and the quantity of bugs. Basically what they are looking to do is keep the bugs in their mid-life stage. This is where they are most effective, and gives a great indication of the overall health and balance of the plant operation as a whole. Bugs that are too young or too old are less efficient, and indicate either a current problem, or potential issues that need to be addressed immediately. The state of the bugs tells them what kind and how much of a treatment needs to be applied. If these bugs get too far out of line they bring in bugs from other plants to supplement. They even have abilities to pass on information to the cities in charge of the incoming wastewater should illegal/detrimental substances be introduced into the system which may cause havoc. The cities will then do investigations into things like illegal dumping and they have methods of tracking down offenders.
At this point I have never heard of JU plants having onsite labs.
We started at the back of the “liquids” section and worked our way forward. This reverse was done because of a lot of construction occurring at the time. First were the disk filters.
This is nothing special. It is simply another stage of filtration that removes particles down to 10 microns. These are self-cleaning filters and the cleaning mechanism is triggered based by flow rate of the water passing through. It is worth noting that at this point I still have not smelled even a slight hint of a sewage odor, even with the doors of this filter open to allow us to peer in.
Next up was the UV treatment phase. The UV treatment takes place under the floor in this area. Note the boxes of UV light bulbs that are being replaced. The bulbs need replaced every ~12,000 hours, or about 1.5 years.
One of the panels in the floor pulled back to display the energized UV section. Note the greenish color being reflected off the inner parts of the treatment chamber.
A rack of UV bulbs removed for maintenance.
It is worth noting that UV is a very inefficient way to treat water. This plant is currently building a chlorine treatment section that will soon replace the UV treatment. Chlorine is much more effective, cheaper, and easier to monitor and control.
This view is looking out over the new chlorine treatment section that is currently being built.
At this point the water is considered fully treated (based on daily testing to ensure compliance) and will be returned to the cities or Gila River Indian Community as reclaimed water (or replenished into the aquifer as needed). It is also worth noting that reclaimed water can be extremely clean at this point in the process with the exception of pharmaceuticals. Illegally disposed of medications are not specifically treated at this point (although the technology exists and to a large degree happens naturally in this process). Also, post handling (after this plant) of the water may be different, so I would highly recommend you not go swimming or drink it still).
JU’s method is to give reclaimed water to the golf course also owned by the owners, while apparently forcing lawsuits for other reclaimed water users in San Tan Valley (I. E. Johnson Ranch Golf Course/First Swing Golf, ACC docket number: WS-02987A-16-0017) and then use ground water replenishment methods to get rid of the rest. It should also be noted that it appears many of these things are being addressed by EPCOR at this point, so props on them for doing the right thing.
Next up we were taken into one of a few master control centers (MCC).
This is where the electricity enters, pumps and valves are controlled, monitoring equipment is staged, and SCADA data is gathered and sent back to the SCADA room. Not a lot going on in this photo, but I can assure you that while I did not get it in the picture, there was a large Uninterruptible Power Supply (UPS) bank in the corner. This UPS bank is to keep things running between a power failure and generator spin-up. Those generators are also tested monthly to ensure they work correctly. Additionally, both power feeds from SRP (yes, they have 2 physically separate trunks from SRP from physically different sides of the plant both capable of powering the plant individually in case of a power failure on one trunk) are physically disconnected on a periodic basis to ensure all systems function properly and technicians are kept abreast on failure scenarios.
It has been said by others (and I may be paraphrasing) that JU pretty much has the oldest, cheapest generators that could be purchased that may, and in some case do not, meet minimum requirements for the application. They also do/did not test on a regular basis and when tested they did not work correctly. It is also important to note that at least one SSO has been attributed to SRP power outages (due to storms), and I suspect more given the correlation of heavy rains and lift station overflows (ACC Docket Number: WS-02987A-18-0050). Also, I have never heard of JU having dual power feeds to any of their plants. Again, EPCOR has been addressing these failures and correcting what it can as time and money permit.
Continuing the tour, we are still working backwards, we get to the “step 5” in the diagram above, the Secondary Clarifier.
This is a picture of one of the maintenance panels opened up. At this point the water is already extremely clear and the turbidity is down to virtually nothing. The water will spend about 3 hours in this clarifier. It is also important to note that there is nothing but a rainwater type of smell coming from this door. I literally stuck my nose down inside this door and it smelled like a muggy room. In fact, the original design of this clarifier had an air handler pipe coming off the top of this tank and feeding the input to the pumps that supply the air to the Aeration Basin’s. That pipe has since been cut and blocked off because the air quality was so good that there was no benefit to trying to capture and reuse it. The only thing that was happening was extremely moist air was being pumped into a multi-million dollar air pump causing corrosion and decay which greatly increased maintenance costs. So the best way to save taxpayer dollars, both in equipment maintenance costs and operational electricity costs, was to simply cut and plug the pipes.
Next stop is another MCC, but it looks just like the other one except for a large window.
Inside this window you can see the massive aeration pumps. I can’t express how impressive these things are. They would not allow us in the room because of the sound levels, but these things are huge. They also run on 4100+ Volts. Of course I had to ask them if the tree was helping on their air clarification…they confirmed that it did.
As we walked out of the MCC we could see a bunch of the construction. What a refreshing sight seeing PROACTIVE construction. The plant still has headroom for growth, but instead of waiting until the last minute, is expanding ahead of the anticipation. This is an area where the Johnson Utilities owners should take note!
A couple of the MASSIVE generators (note that there are more than this onsite).
Now we arrive at the access point to one of the numerous, 25 foot deep, Aeration Basins. In this picture you can see one of the guides pulling up a sample cup of fluid. Don’t think about it, it’s a bit disgusting. You can definitely get a feel for how the bugs are doing their job. The air helps keep them happy and productive. An interesting factoid: So much air is being pumped into this basin that if you were to fall in, you would be gone. Normal water density is 1 gram per milliliter. They claim the density of this liquid is about 0.6 g/ml. In other words, you can’t swim in it. You would sink to the bottom immediately with no way out.
Another interesting tidbit: Standing in the breeze of this open pit of nasty poop-water, the stink was far less than driving down Hunt highway by the JU plants (according to my nose). At this point we are only 4 process steps away from raw sewage as shown on the operational flow above. The big difference as best I can tell is that GWRP intentionally treats their incoming sewage differently. The headworks (incoming point of the raw sewage) was having an issue at the time of the tour, so we couldn’t visit that area, but fundamentally they screen/filter, then go through a grit removal tank and primary clarifier where they take the air from those enclosed facilities and treat it with a caustic treatment, followed by a chlorine “rain” for good measure. That way the rest of the process is relatively odor free.
Inside one of the new aeration basins. This is new construction and this is being tested with water in it. It doesn’t look 25 feet deep from here.
At this point in the tour we transitioned to the solid treatment area. Unfortunately there weren’t many interesting pictures taken of this area as it mainly consisted of pumps and pipes. We did get to walk through the area where they load the digested/dehydrated sludge into semi trucks (it was inside a building) and it was the worst smelling area of the plant. This smelled almost exactly like the smell many residents that live by the Section 11 WWTP deal with from their house on a routine basis. It was bad, but I want to reiterate that we were INSIDE THE BUILDING. Not open air as Section 11 is.
Finally, we couldn’t see inside the digesters or centrifuges (for removing water from the sludge before it is given to farmers or landfill), but we did get to see what happens to the methane that is given off in the digestion process:
This is a picture of the “flares” used to burn off the excess methane. You can’t really tell in this picture, but they are actively burning here. It is important to note that some of the methane is recycled to use for heating the sludge to aid in the digestion process, so it’s not all wasted. It’s also important to note that these are 12 years old already, but they don’t look like it.
Fundamentally it is clear that this plant is run relatively efficiently. Maintenance is kept up on a routine basis. Every attempt at reviewing efficiency indicators is done multiple times per day to make sure things are running smoothly and so they can find issues before they become big issues. Improvements are being made proactively. There were no areas that appeared to be “Swiss Cheese” (ACC Docket Number: WS-02987A-18-0050), however we did not get to view the headworks area of this plant.
I also broached the subject of spills, or SSO’s with the GWRP. I had to pry a bit because no one could really remember anything substantial. As it turns out, the biggest spill in their 12 year history occurred about 1 week prior to this tour, and was due to an aging pipe that dumped, get this, a whopping 200 gallons of sewage (not enough to fill an IBC tote). The other 2 spills were far less severe. None of the spillage left plant boundaries. Considering a single spill in recent history for JU was multiple 10’s of thousands of gallons, I think I am OK with a truly accidental spill of 200 gallons. It just goes to show how much more efficient and well trained the staff is.
A question was also posed to the staff about why you keep a “poop plant” so clean. The answer was simple: It’s all about worker psychology. The more clean their work environment, the more apt they are to handle real issues with enthusiasm. It’s pretty simple, keep your workers happy and they will keep you happy. Another lesson that the owners of JU are learning the hard way.
All of this is done with a staff of about 25 people including administrative staff, technicians and janitors, etc. At night, the plant is able to be run and be maintained by a minimal staff of two personnel, which will soon have to be expanded due to all the construction improvements being done.
It is also important to note that this is all being done as a cooperative effort between multiple towns and cities. Without knowing the details of the agreement, it was discussed about how a private utility may utilize this plant and it’s efficiency. The answer was that it probably shouldn’t be that difficult. Just ask and let the discussions begin.
With all of this said, I want to give EPCOR USA one more mention and thank you. While the comments in this post were meant for JU as it was, nominally, before the interim manager, much has changed for the better, and I suspect we will see continued improvements as EPCOR continues to move forward. I urge EPCOR to continue fighting for the people, and to not get too wrapped up in JU ownership politics as this would be disastrous for people that have fought so hard.