All about the Poop - ElectroScan Low Amp Electrode Warning

One of the things that has been really convenient on DreamChaser is an on-board waste treatment system.  Like most things in the boating world, the “nautical term” for this is a “Type 1 Marine Sanitation Device” or MSD for short.  I think non-boaters would be surprised to know some of the details around how waste (sewage) is dealt with.  There are essentially 3 legal ways to manage waste on board a vessel and they go up in cost and complexity as the get more sophisticated. 

Type 3 Marine Sanitation device 

These take on 2 different primary forms. The first is a holding tank on a boat that has to be pumped out into a proper disposal on shore or the other is typically recognized as a Camping toilet or portable toilet. They essentially contain the waste in a unit that can store it and then empty at the proper location (on shore or more than 3 miles off shore)

Type 2 Marine Sanitation device
This is a flow through treatment system that can use maceration, disinfection and some type of biological treatment.  The details are not quite as pleasant, however, these can be discharged as long as there are “no more than 150 milligrams of total suspended solids per liter”  

Type 1 Marine Sanitation device

The last type is a unit that also uses flow through treatment method however must not discharge any suspended solids and must contain a fecal coliform bacteria count below the threshold of 1000 per 100 Milliliters.

The Type 1 unit above actually treats waste to <10 per 100 Milliliters, however it can not be certified as a Type 2 due to the suspended solids requirements of a type 2 that require aeration and larger amounts of electricity and are not as feasible on boats under 65 feet due to space and power constraints

The convenience is that the system just works 95% of the time and you don’t really have to think about it.  For example we have a combination of Type 1 and Type 3, so our system automatically monitors the volume in the holding tank and then starts the treatment cycles automatically and shuts off when complete and includes key to lock the system off for times when you are in an EPA designated no discharge zone (or NDZ).  

When we first bought the boat, the unit seemed to turn on and run, but would give an error and stop about 30 seconds into the treatment.  That was when I educated myself on these systems and did my first cleaning of the Electrodes with Acid according to the Manufacturer (Raritan).  It worked great and I want to share the information below so that you too can keep your unit running for a long time, or possibly even restore a unit that has stopped working.
There will be links within this blog directly to Raritan Engineering Manuals for these procedures as well.

You start this process by flushing the toilet several times and your goal is to push all clean water into the system.   A good bit of information to know is how long your sanitation hoses are from the toilet to the ElectroScan.  In our case, they go to a holding tank first then to the ElectroScan, so we had to factor in longer runs.  Once you know how long the hose is, you can determine with the chart below how much water you have to flush through the toilet to get to the end of the sanitation hose.
Typically boats use a 1.5” diameter Sanitation hose and  when doing so, 10’6” of hose will hold 1 gallon of water.  So if you have 24 feet of hose between the head and the ElectroScan, you would need a little over 2 gallons just to reach the ElectroScan.

It is very important that you do NOT run a treatment cycle while the Acid is in the chambers or it can, and will, damage your electrodes.    The way to ensure that they don't run is to go to your Control Panel for the ElectroScan (on the far right side of the unit when looking at it from the front) and unplug the Red, Orange and White leads.  These are the positive connections to the Electrode Pack, the Macerator and the Mixing motor.  
Disconnecting the Red, Orange and White wires
In our case, we turn off the large battery switch that feeds power to the holding tank, ElectroScan and Electric Head, disconnect the wires and then turn the battery switch back on.  With it setup this way, we can still flush the toilet into the holding tank if needed and can activate the pumps on the holding tank without worrying about the electrodes charging.

Once flushed and the plumbing is clear it is time to put in the acid solution.  I recommend using a sturdy bucket and start with 3 gallons of water in it.  You then need to add 1 and a half pints of Muriatic Acid.   CAUTION - Be sure wear protective gear.  I use safety glasses to avoid a drop of the acid solution getting in my eyes as I am pouring this into the bowl.  

Now you will want to add this Acid/Water mixture into the ElectorScan by pouring it into your head and flushing repeatedly. Do this without adding more water through the flushing. You just want to move the diluted acid from the bowl to the ElectroScan treatment chambers.  

Once the 3 gallons has been introduced to the system, you want to run another 1 gallon trough the toilet.  The purpose of this is to flush the acid mixture out of any other components in the system such as the head itself and any “Y” valves but leave the not flush so much that you push the acid solution beyond the electroscan unit itself. 

Raritan recommends letting this solution sit for “at least 45 minutes”, however I have found that best results when I let the solution sit in the unit for about 3-4 hours.

After the elapsed time, you will want to remove all acid from the system.  You do this by running at least 10 gallons of water through the toilet to rinse away the acid before you connect the wires and energize the unit.

Now turn off power to the entire unit and connect the Red, Orange and White wires again to the control box and it is time to test the system.   You should notice a significant improvement in amperage at the control panel status panel during a treatment cycle.

It is important to keep in mind that the ElectoScan units rely on salt water.  it is the salt that make the water in the unit more conductive.  To that end, if you are in fresh water, great lakes, inland rivers, or (like us) have your toilet fed directly from your fresh water pressure system, then you MUST add salt to the water so that it has the correct salinity to the ElectroScan.    

There are several options to accomplish this.  The first is using a 2 gallon salt feed container that taps into the seawater toilet intake and mixes the salt water as the seawater comes into the bowl during a flush.  There are 4 gallon automated systems that also plumb directly to the pressure water system and are controlled by the ElectroScan unit by monitoring the salinity of the water in the treatment chambers and pumping in more on demand as needed.   We use a fairly simple method and it works fine too. We keep solar salt in a container in the bathroom with an old coffee grounds scoop in it.  Each time someone uses the restroom, they add 4 scoops of the salt directly into the bowl before flushing.  

I hope you have found this article useful, and it helps to ensure your MSD continues to run in top condition.  We have now made this part of our regular maintenance schedule and we do it every 6 months even if we are not seeing the reduction in amperage at the Electrodes during treatment.  

Raritan Hold-n-Treat System - This is a combination holding tank, ElectroScan, and a series of transfer pumps and automation to manage the waste in the tank

For those on fresh water or with a fresh water plumbed see this document for the 4 gallon automated salt feed solution.

I hope you found this helpful and see after reading this and watching the video that this is not nearly as hard as you may have imagined it to be.  I know I toiled over this for a few months before we did this treatment the first time.  I was so worried about what it was going to take and how 'dirty' this job would be that I put it off, and it turns out that this is not a dirty job at all. 

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May you have a following sea and a gentle breeze.