I have a customer who asked us to help them to recycle the water used in the laundry process (washing clothes and linen). They want to use the water in the laundry process again once recycled.
The daily water usage is 600 liters per day total from 7 different industrial type washing machines.
Can Ultra Filtration and Carbon Block technologies recycle the water back to the desired state?
How about the soap and bleach elements, how to take care of these?
How many times can the water be recycled through this process?
one of the main issues with laundry water reuse is the concentration of lint which needs to be filtered out. Also I would imaging that your client will want to retain as much of the heat as they can, which is where RO fails as the membranes typically fail around 45c. I would look at using an Organic Destruction Cell, as it will remove micro pollutants, and organics at a higher temperature.
Hi Shawn. Laundry wastewater requires biological treatment to remove the soluble organic contaminants from the soap and detergent, but biological treatment can be problematic in North Americaas a result of low phosphorus detergent formulations. As a consequence, if treating laundry wastewater on its own, nutrients generally need to be added to support biological oxidation. There are a number of ways to approach treatment. You could consider electro-coagulation or chemical coagulation/flocculation to remove suspended solids and colloidal solids prior to biological treatment, followed by filtration (possibly MF or UF membranes). Like any industrial wastewater treatment process investigation, pilot testing is highly advisable due to the extreme variability between laundry operations and wastewater characteristics. RO membranes have also been used, but typically reject around 25% of the wastewater flow to sewer - so water conservation levels are much lower than using more conventional treatment. The degree of treatment required greatly depends on what level of residual contaminants may interfere with laundry cleaning efficiency. Biological treatment with ceramic micro or ultra-filtration membranes have also been applied - but the ceramic membranes are still very expensive.
600 LPD does seem a little low. However, we are able to scale to this size for laundry closed loop recycling. Yes, ultrafiltration is used. It is used in conjunction with membrane bioreactor process. We then follow with an advanced oxidation process (AOP) which involved ozone and UV. Our process scales from 300 to 50,000 LPD
600 LPD does seem a little low. However, we are able to scale to this size for laundry closed loop recycling. Yes, ultrafiltration is used. It is used in conjunction with membrane bioreactor process. We then follow with an advanced oxidation process (AOP) which involved ozone and UV. Our process scales from 300 to 50,000 LPD
I'm not 100% sure, but quietly confident that your bleach and soaps would be taken out of solution with electrocoagulation. In this "oxidised" state it would be very easy to separate and then filter the cleared water for reuse. Worth a test at least if you have access to a pilot scale EC unit.
Published
by Wayne Pozarycki, ZBiG Consult - Managing Director
The simplest type of greywater use is to collect water in a dishpan as you handwash dishes, and then toss it over your flowerbeds or fruit trees. This is a wonderfully simple, inexpensive way to tap into greywater, but with just a little more effort and expense, you can capture much more water.
Greywater is household wastewater from bathroom sinks, showers, tubs and washing machines; it has not come into contact with faces or passed through a toilet. Some intrepid homeowners recycle their greywater by using it to water their lawns or gardens or by using it to flush their toilets. The greywater can be treated first, or it may be used untreated; under no circumstances, however, should it contain bleaches, dyes, bath salts, fabric softeners or detergents containing boron — an excess of boron is toxic to plants.
All required laundry detergents and auxiliary washing preparations are fed into the line over a dosing system by computer control as well as the water is added.
The washing water is thermally and biologically processed after the washing operation, so that the cleaned water can be fed back again into the washing circulation process. Therefore, the laundry procedure does not generate any wastewater.
The process exhaust air of the washing operation is being used to produce energy – it is re-fed into the process (laundry line, dryer) again as steam for recovering heat.
A thermal afterburning system emits the waste exhaust air after treatment as „clean air“to the environment. The exhaust air from the drying process is used for recovering heat for the dryer. Waste exhaust air is being emitted as “clean air” to the environment after the treatment in a regenerative afterburning system.
In order to build the LWR you need to have room directly (or nearly) above your washing machine for the tank. You also need a way to secure the tank safely, because when full it will weigh more than 250 pounds.
Typically industrial/commercially consumes 18/26 liters per kilogram of linen washed. So if the laundry is using only 600 liters per day on 7 washer extractors, it might be small domestic washers.
And such low water quantity the recycling would not be cost effective. Usually a 7 industrial washer extractor with minimum of 2500 kgs/day can be very ideal situation of recycling with fair payback.
We do laundry waster water recycling with proven technology and our customers have saved over eight billion gallons of water.
Let me know if you need more information on our product line.
I totally agree with you, Surej! One of our clients consumes 10m3 per day per machine. 600 L with 7 machines is not indusyrial like and as I mentioned in my post, not economically viable.
The first wash water will be dirty and needs to be drained. The next rinses should be collected. Followed by simple flocculation and sand filtration (incl back wash) + UV and than reuse.
Yes. I think some form of synchronization with the washing system will be required to optimize size and energy consumption of the recycling system. That is assuming it is on industrial scale. I think feed buffering is definitely a requirement for the washer system.
We have also been requested by our friends to help them find ways to reduce the wastage of water in the laundry process. The requesting unit processes about 30KL- 40Kl of water per day. they shall be interested in bioremediation techniques to extract raw water for the initial rinse cycles. Suggestions may please be sent to pk@jugapro.com
Hi Shawn, Is there a standard flow rate? Pulses or continuous. I would think with 7 machines, probably not synchronized, would have huge fluctuations in rate and duration (24/7?). My context is ecological design using siphons, basins, and continuous flow tanks for organic breakdown of the compounds. With this the volume is buffered and collected for continuous flow in a series of tanks. Much like water systems in the water short islands, the water is recycled. Very low energy, clean water for reuse, high organic output, and a PR benefit too. It takes space and a strategy that begins at the start of the washing process. Low cost ecological system.
I work in a membrane factory, we manufacture and sell UF membranes, and we have the experience for filtrate laundry water. We can discuss on this project further by email, my mailbox is: export006@aqucell.com. Wait to hear from you.
I design eco systems closed and semi closed. If I understand you correctly you have a chlorine problem. (chlorine filtering must be part of step #1)... suggest cupric sulphate. This coagulates and makes it easy to remove without expensive filters. Next would be a selection from which to choose. You can use the remaining water for agricultural use, bio toilets, or venture towards 100% recycling of your water using a biodigester with a bio generator. When using RNA microbes for bio degradation electrons break away and be collected for your energy needs. Collect, use, long term storage of rainwater is always a plus. Then you can grow food for yourself and your wash customers. Maybe open a restaurant on location. Talk about a captive audience. wash, eat, learn natures bio systems that cost you zero. contact me for details on all of the above.
regulations are the concern. They interfere with the natural process. The only purpose for any regulation is to make money. Take from the poor and give to legislators and their corporate accomplices. These microbes have been used for the last 40 years. Passed every inspection. Declared 100% organic. Can be shipped and used with any country belonging to the WTO. But seeing how they eliminate the need for regulations and our EPA these criminals infest every part of our society. Cochroaches all.
There are several companies specializing in recycling laundry wastewater. One of the best is Pure Pulse marketed by Water Recovery System. They employ a ceramic membrane process. As well saving water it also reduces energy consumption. Google Pure Pulse
A simple system commonly known as a laundry to landscape system could be optimised to industrial scale if need be. Laundry water either for reuse in Laundry or for use in irrigation.
The laundry to landscape system allows for a limited number of trees and shrubs to be irrigated by utilizing the built-in pump within the washing machine. The water pumped from the washing machine is unfiltered and is simply dumped onto the plants and trees. Valves are added to provide some flow balancing to the system. Because the greywater is unfiltered it is mostly not used in drip irrigation systems.
Also, using ozone has over time proven to be inefficient and expensive especially on a large industrial scale as for oxidizing these soluble pollutants. Use of biological treatments is presently gaining sway and is most sustainable for this process.
Published
by Amali Abraham AMALI, Graduate Student (Integrated Water Resources Management - IWRM)
1 Comment
Hi, Amali, Could you please indicate studies on "using ozone has proven to be inefficient..."? Expensive, yes, I admit, but inefficient.?, Where are the facts based on data?
Hi Pedro. I am not an expert in this field but it is of concern to me and I have had to read lots of related literatures assessing the system functionality. The efficiency of the system often comes into question due to the need to maintain an optimal ozone dosage. Low dosage may not effectively inactivate some viruses, spores, and cysts. And because the concentration of ozone generated from either air or oxygen is so low, the transfer efficiency to the liquid phase is always a critical economic consideration.
Published
by Amali Abraham AMALI, Graduate Student (Integrated Water Resources Management - IWRM)
First you need selfcleaning fine screens or sieves to retain and remove fibers and other large solids which would otherwise result in clogging and damage downstream. Next a gravity trap shall remove the sand/grit upstream of a mixed buffer/equalisation tank where the bleach will decompose in short time (depending on wastewater temperature). UF as proposed by others will only remove solids. As a result all soluble pollutants including smelly volatile compounds would be recycled. Using ozone would be very inefficient and expensive as main treatment to oxidize these soluble pollutants. Instead we use advanced biological treatment as most sustainable and efficient main treatment followed by UF and ozonation as polishing.