Drain Water Information

The Problem Overview

During the cutting process the WAZER combines high pressure water and abrasive to quickly erode the work piece. This process creates waste in the tank that is made up of water, abrasive, and tiny particles of the material being cut and the cut bed. Before the WAZER expels its waste water it ensures that the majority of the particles are retained in your machine with two different methods. The first method is by means of a series of baffles in the back of your machine, where suspended solids have time to settle out of the water column. The second method is by means of filtering the water that will be dumped by a set of 0.6 mm stainless steel mesh filters (50 mesh). A small percentage will still be suspended in the water and an even smaller percentage will be dissolved in the water that is exiting your machine The exact amount will depend on a variety of factors. The following article will go through trying to quantify and understand what is released as well as local regulations.

In summary, for most townships the waste water produced by WAZER will fall below local regulations for individuals. This of course assumes you are cutting non-toxic materials. If you have concerns it is easy to get the waste water tested to see if your particular case passes your local regulations.

Wastewater

WAZER separates the majority of particles from cuts and retains them in the tank using baffles, abrasive buckets, and fine internal mesh filters,. This waste is disposed through solid waste processes. However, it is possible that trace amounts of that material can be found in the drain water of the system.

The elements that combine in the waste water are in two different states. They can be suspended or dissolved in the water column. Those that are in suspension are larger particles that will eventually settle out. However, this settling can take an extended period of time combined with low speed water flow. The elements can also be dissolved, where the particles have reacted with the water and will never settle out.

These states are important due to local drain water regulations and the physical impact on your water drainage system. What you are legally allowed to dispose of down your drain is controlled by local drain water regulations. This will be a combination of the chemical makeup of the elements (ex: cutting lead or copper), to the amount of particles in suspension. The physical impact on your system involves situations such as clogging due to the suspended particles settling out of the drain water somewhere in your drain system. This is of particular importance in older buildings and those where the drain line may have a shallow pitch.

How to Address Concerns

Local Regulations:

Let’s first address the topic of local regulations, which vary greatly across local municipalities and govern the concentration that is allowed to be drained by any individual/entity. The best way to get this information is to contact your local water company (whoever you pay for water supply and sewage) and ask them for the local regulation standards. They will be able to either give you direct information, or put you in contact with someone who will. Another way to get this information is to simply search the internet for “waste water limits” or “ wastewater quality control” for your particular area. These days many counties and city’s governments post this information on their websites. You can find limit lists in table form that go through all of the different substances that are limited in your area, as well as the overall suspended solids limit. Make sure to note if the regulations exactly apply to you, many times the regulations for individuals are far less restrictive than that for a large organization because the actual volume of water disposal is substantially less. An example of a representative table is included below. This is taken from New York City’s dewatering application. If you look closely you will notice that one of the restrictions, the total suspended solids (TSS), is for large organizations, which are defined as producing more than 10,000 gallons of waste water a day.

The next step in this case is to access the MSDS (Material Safety Data Sheet) of the material you will be cutting. These can be obtained from your vendor or for common materials in online databases. This gives you detailed information on the material and the properties of it. Now cross reference the elements that your local authorities regulate with the contents of the material composition of the material you are cutting. If the contents on the regulated list overlap with the contents you are cutting, you may want to run a water test. Note, that just because there is an overlap does NOT mean you cannot cut the material (in most cases you still will be able to!). This is because the regulated element is likely to have an allowable limit or threshold (concentration) in the waste water. Therefore, this situation may require testing of the water to see if you are below the limits of the regulated substances.

The testing mentioned above is run at a laboratory on the waste water coming out of your machine. This may seem like a big deal, but its not! Such laboratories are located all across the country, and can be found by identifying if a laboratory will run water and wastewater analysis for residential purposes. Some key words to search for are local “residential wastewater testing”, “commercial wastewater testing”, “water and wastewater testing for residential”, and other such terms.

Let's walk through a simple example of cutting that we conduct in our WAZER Product Development center everyday, cutting of thin 1/8" aluminum. We have accessed the MSDS for our Aluminum alloy and also our local authority list of regulated drain water elements. We have found that TSS must be <400mg/L and that Aluminum is a regulated element to not exceed 20mg/L. We perform this cut and grab a sample of the drain water exiting our WAZER and bottled it up in a clean container. We next found a local water testing laboratory and send them the bottle to test for TSS and Aluminum. We waited 5 days for the results and they showed that we can expect to have approximately 382 milligrams of solid particles in suspension for every liter of waste water of which 16.3mg/l is aluminum. As a result, we know we are in the clear with our local regulations. It is important to note that this percentage is particular to our setup, other materials and other setups will have different results. The results directly from the water testing lab of the above test are below.

Local Drainage System:

The second topic to address is the effect of drain water on your local drainage system. This involves the drainage system in your house or shop, as well as the public drain system that your home or work drains into. Based on our internal testing, WAZER has concluded that there is a minimal hazard of clogging in the pipe systems the WAZER drains into. However, as there are suspended solids in the water, there will always be a small risk of a clog occurring in systems that are older, already partially clogged, or not built with a standard drain pitch.

When the WAZER drains through a typical plumbing system, it first encounters a p-trap. This is the bend underneath a sink or toilet that catches large and/or dense objects before they get sucked into the main line. Here, some sediment from the WAZER waste water will build up over time. However, internal testing has shown that this will not cause clogging on its own because after just a few hours this sediment will reach a steady state and any more that tries to settle will be washed away. Additionally, it has been observed that the sediment buildup is washed away when a higher volume flow passes through. In other words, if the sink or system that the WAZER drains into is flushed with fresh water, then the quantity of sediment buildup will decrease.

After the p-trap, a section of straight plumbing will connect your p-trap to a larger primary drain pipe in your household or commercial setting. The common limit for pipe length is 6 feet or less. WAZER also tested to find out if there is any sediment buildup throughout this worst-case scenario of 6 foot pipes. The three most common residential and commercial pipe sizes were tested; 2 inch diameter, 1 ½ inch diameter, and 1 ¼ inch diameter. After testing it was observed that there is some slight sediment residue that builds up along the bottom of the pipe. This residue is a very thin layer and does not cause any issues with drainage.

The overall conclusion from WAZER’s internal tests is that in most situations there is no issue from the drain water going through residential piping systems. However, if you believe you already have partially clogged pipes, non-traditional plumbing, or routing prone to clogging (long, shallow drain pipes), then you may want to monitor your drainage situation very carefully to make sure you do not clog and overflow. You can also implement additional ways to reduce the chance of clogging even further, as will be elaborated next.

Solutions

Overall, drain water from WAZER is not a concern for the majority of systems. However, if you feel inclined or are required, there are a few simple extra steps that can be taken to ensure that you limit the amount of sediment being drained from your system.

A settling tank is the cheapest and easiest method, and is also highly effective. By allowing more of the suspended solids to settle out before the waste water moves to the drain, you can reduce the concentration by large quantities. There are many different settling tank methods, involving baffles and other features. The simplest incarnation is a container that overflows into your drain solution (ie. a 3 gallon pale that sits in your shop sink illustrated below). As an example, WAZER created a basic settling tank and measured the effects of it with regards to the suspended solids. The results showed up to a 2.5x decrease in suspended solids.

Another method is to use an extra filter in-line with the drain hose. Depending on the micron size of the filter, this can eliminate a lot of the larger suspended solids in the drain water. However, the finer the filter is the more frequently it will clog. This is an important trade-off to note.

If you have any more questions about proper disposal of WAZER drain water, please check the on our website at www.wazer.com/faq or contact us at www.wazer.com/support

Works Cited:

-WAZER internal research and testing -https://www.analab.com/ -https://www.thefabricator.com/article/waterjetcutting/disposing-of-waterjet-abrasive-the-right-way -http://www.nyc.gov/html/dep/pdf/water_sewer/dewatering_application.pdf