Pumping Technology into our Sewage Pumping Stations

Transcription

1 Pumping Technology into our Sewage Pumping Stations This presentation is about how we continue to deal with our unprecedented growth which has put a high demand and strain on our plumbing infrastructure. It talks about our evaluation of the failures we were encountering via RCA s, the various options we looked at to solve the problems and the final modifications and enhancements we agreed upon that would best suit our unique requirements, the tenants need and those of the travelling public. Like any other large facility Toronto Pearson Airport Plumbing system and sanitary sewage system is one of the very critical systems that is out of sight but very essential to keeping the facility open, humming and operating flawlessly. Airports are unique in nature, unlike other large facilities like malls and stadiums which handle large groups of people but slow down at the end of the day, where maintenance can take over and deal with breakdowns and system upgrades. In addition, at these facilities generally all food establishments and washroom facilities are centrally located. Due to our strong economic growth maintenance activity windows at Toronto Pearson are a thing of the past. Closing out facilities to perform maintenance must be vetted through several stake holders. There is the additional security aspect and the restaurants and washrooms are located across the airport to provide for passengers. Through my presentation I would like to illustrate how we have been evaluating the different system components, specific needs in different areas and the technology chosen and implemented to improve our system reliability. Sustainability through Reliability presented at the 2015 Maintrain Conference talked about how the influx

2 of the number of restaurants contributed to the high number of plumbing drainage failures. By carrying out an RCA on the failures of the plumbing drainage lines we could pinpoint the reasons for most of the failures related to restaurant drain lines. That RCA primarily focused on the Tenants providing Food and Beverage. We could engineer out the root cause of the failure, change our design standards, and create a sustainable and economic option for our Food and Beverage tenants on how they deal with fats and oils. Instead of going down the drains, fats and oil are recovered and tenants get credited for oil they recycle, in addition most of the organics get collected and disposed of in our organics bins. However, that was considered our starting point or the first phase of improving the reliability of our plumbing drainage and pumping system. Due to the complex nature of the airport and the fact that there is a single drainage line which receives drainage from the food prep kitchens, restaurants and washrooms we were also seeing failures of a different nature caused due to the excessive amount of toilet paper, paper towel and medical syringes down the drains. These not only caused blockages in the lines but caused failures to the pumps in the pumping stations. The elevation of the airport terminal buildings is far lower than that of the region s main sanitary sewer lines. Hence the system is designed such that the drainage lines empty into sewage sump pits serving specific areas. These pits are strategically located across both the terminals. Pumps located in these pits then pump out the water through the terminal areas and out to main sewage lift stations located offsite. The sewage collected in these massive underground storage wells must then be pumped out to the region s main sanitary drain lines.

3 In one instance a trunk line that connected the terminal to the main sewage lifts was blocked with a length of paper towel and caused a backup in the service level of the terminal. Our priority was to install back water valves on these lines to prevent this from happening. In addition, we also installed a system that monitored the water levels in the curbside manhole. This simple system comprised of a float connected to a transducer attached to the top of the manhole. When the level rises above a predetermined level it sends an alarm to our Building Management system. This buys our response teams some time to respond and alleviate the problem or divert the water to the adjacent manhole. The area pits in the terminals are generally smaller in size varying from the smallest being 6'by 6' and 6' deep to some of the larger 15' by 15' and 15' deep. The smaller pits have single pumps while the larger consist of dual pumps (primary + backup), floats, some have grinders and ultrasonic level controls with float back up. Quite often we would have failures of the pumps due to excessive amounts of toilet paper, sanitary products, diapers and syringes that would get sucked into the pump. The usual course of action was to remove the burnt-out pump and replace with another. The cost of the pump was not a major factor, but the labor to remove and install, interruption to operations was the driver that pushed us to look for more reliable options solutions. We implemented a very comprehensive maintenance program for the pumps in our main sewage lift stations as those failing could cause the shutdown of the terminals. But through RCA s we discovered that we were still missing important steps, components and technology in our system that were causing us to run into failures with our system. We began evaluating our pits and the failures and sought out solutions.

4 The next steps we took was to deal with syringes found floating in the pits. Several of the washrooms had no place for travelers to dispose of their syringes and hence were flushing them down the toilets. A quick fix was to add Sharps containers in all the washrooms so that they are clearly visible and in handicap stalls so that everyone could safely dispose of this material and keep it out of our sump pits. Our next step was deal with the issue of paper towel and excessive amounts of toilet paper build up. We found that when the blockages occurred we often found long lengths of paper towel was the cause of the blockage. Paper towel does not break down easily and some of the dispenser did not dispense single cut sheets, but user could dispense the desired length they felt like dispensing. We removed these types of dispensers from the bathrooms and replaced them with single cut dispenser where we could adjust the length of the sheet dispensed. We even carried out extensive trials with different types of hand dryers. Surveys carried out through the trial period showed that travelers and employees preferred using paper as opposed to hand dryers. Our investigations also revealed that the water was not being churned enough to break down the tissue paper and be pumped out of the pit via the pump. It kept building up and floating on the surface. Eventually getting ingested into the pump causing the pump to jam and burn out. We looked at the different types of submersible pumps that were installed and none of them were truly suited for our applications. We researched the market for alternatives and found there were several types of pumps available. We did extensive trials and finally tried out a Flygt 3000 series pump with a flush valve mounted to it. The impeller we picked was the N type impeller. This specially designed impeller does not

5 allow material to get clogged between the pump body and the impeller. The optional flush valve is designed to direct a water jet out the side of the pump which caused the water to churn enough so that it broke down the tissue paper and allowed it to be pumped out through the pumps. We ran this combination on a rental basis for a period of over 6 months and it ran without a single failure. We felt confident that this would be the best solution and gradually are converting all are pumps in the smaller pits to this 3000 series type pumps. As an additional benefit this pump seemed to handle syringes and other sanitary products without getting clogged and failing. Plus, with standardizing this pump for majority of the applications it is easier for us to have a couple of similar spares that we can keep on hand in case of failure. Our pump supplier also carries several of these in his rental inventory so there is always an alternative back up plan. For the pits that do not have submersible pumps we have added heavy duty mixers that churn up the water so that all the paper and build up breaks down and remains in a suspended state for it to be pumped out. Finally, we looked at our pumping station controllers as we had experienced a failure with the Terminal 3 station and had to operate it manually until we could get it back on track. The hardware needed upgrading, the programming was very basic and had very limited functionality, but the biggest concern was that we had no access or control over the software. The company that had carried out the programming had closed and the owner now operated under another name. We were fortunate enough to track him down and managed to get the system up and running a few days later. It was at that point we decided that we had to consider better options. Pearson Airport now operates like a small city by comparison, so we decided to look at how other similar operations were handling their sewage stations by

6 comparison. After doing some research it was quickly apparent that the next generation of technology for water and waste water pump stations was the Pump Station Managers. Pump station managers combine the best of PLC s, RTU s and pump controllers into a comprehensive and intuitive package. It integrates numerous control panel components hence lowering panel costs. The preprogrammed logic is designed to significantly reduce operating costs and is easily set up via the Setup Wizard. There are several benefits and features of these Station Managers and few are underlined below: Advanced Pump Control Functionality (6 pumps) Max Run time and Run most efficient pump Clean well out by removing Floatables (with Mixer) Multiple set-point profiles Generator Set profile changes Limits max pumps Locked level raises alarm (level device failure) Optional VFD module / VFD accessed via 1 screen Supports Security key Mixer control agitates mixer in wet well Fail-safe probe for monitoring health Fault condition monitoring and retry function Predictive alarm conditions Flow without flowmeter Rapid hardware changeout Quick programming via local compact flash card Data logger for 50,000 events (10,000,000 to Card) History page with detailed fault and data events Firmware and features upgrades easily via web (620) Connects to any modern SCADA platform Built in control panel hardware for insulation resistance testing(meg-ohm-meter), Phase rotation, pump current monitoring, main service voltage

7 monitoring, run time meters, level sensor auto-fail over Odor reduction via max off time Blocked pump detection defines max # of starts The list of features and benefits is extensive and we were really interested in seeing more of this product. We invited the vendor for an inhouse demonstration and were very content with what we saw, however that was in a meeting room environment. If we were going to consider upgrading the stations we wanted to be sure about the product and see all its features in a realworld environment. Luckily for us the vendor had a few installations in the area that we could visit, but the one of greatest interest to us was at the Western University Campus in London Ontario. The visit to the site was very beneficial and seeing the system working exceeded our expectations. It was easy for the end user to set up and make changes without having to carry a laptop to the site. Our staff found it easy to scroll through the menu and try out the user functions with having to worry about corrupting the background programming. The best part of our visit was opening the pit access hatches to find little or no odor from the pit, minimal amount of debris floating on the surface, buildup of any kind was minimal on the floats and level monitoring equipment. With the help of the maintenance staff we could try out some of the pump reversing features to rid the pump of blockages. What really got us excited about our conversation with their maintenance team was that in over 3 years of the system being installed they did not have a single blockage or failure of any nature and would even forget that it was in existence had it not been for the remote monitoring.

8 I am happy to say that we are in the stages of upgrading our system to deliver better service to all those who pass through Toronto Pearson Airport.