We are in the process of buying a new waste treatment system. We are currently using a Ion exchange system but I would like to know more about Membranes pros and cons. please reply to this forum or directly to RHORTA@McCurdy.com
Date: Tue, 13 Jan 1998 09:42:53 -0600
Charles Barker@I-O INC
For our application (D. I. water feeding in-line board washer), we have
been using about 3500 gallons/day. With our present Ion Exchange system,
our costs are running about $2K per month for rental/service/replacement of
tanks. When the system is in top shape, we are probably getting about 0.5 to
1 ppm of dissolved minerals in the output stream to the cleaner. That is
probably about 10 to 15 megohm or better quality. As the resin beds
deteriorate, quality drops so we usually switch out beds about once a week.
Straight R.O. system will provide about 8-10 ppm minerals. R.O. system
needs pretreatment and decent (right temp range, ph, etc.) water going into
it. For our application, we will need a water softener and a carbon filter.
An R. O. system is designed to provide a certain number of gpm. For our
application, he suggested a 200 gallon storage tank as a buffer, feeding a
set of resin beds (back to Ion Exchange system), feeding our cleaner. Cost
of complete system, about $17-18K with about $200/month continuing for
consumables and service.
R. O. system this size would take up a space about the size of two filing
cabinets plus space for storage tank. You still need the resin tanks as
polishers or finishers, but their life expectancy increases by about a
factor of 10, so they can be the smaller variety.
He estimates the break even point for cost advantage is at teh 6-8K gallon
per month usage. In our case, there would be a decent ROI in less than one
year.
Hope this gives you something useful. If you wish to call me, my # is
281-552-3328
Charlie B.
Date: Tue, 13 Jan 1998 17:06:10 -0800
Things to Consider with a Membrane System
Membrane wastewater systems work very well for removing precipitated
metals from wastewater leaving a clean clear filtrate. You have to
factor in several hidden costs. I have seen membrane failures in as
short as one year. Most membrane companies only FULLY warranty their
membrane for one year, after that your paying some percentage of the
full list price.
Don't underestimate the cost of cleaning solutions (bleach, acid, etc.)
these costs can really add up if your not properly segregated. Membrane
systems typically don't work well if there is too much organic material
(stripper, developer, etc.) in the wastestream. The more of this stuff
that finds its way into the system, the more you will be cleaning the
membranes. Cleaning frequently is the biggest cause of premature
membrane failure.
For every 100 gallons per minute of filtrate, you will be recirculating
about 900 to 1000 gallons per minute of water. Check with your local
electric supplier and get your KWH rate and ask the membrane supplier to
include the cost of electricity in the operating costs.
We sell conventional wastewater systems that typically have much lower
operating costs than membrane systems. Before you buy a new system take
a look at what we can offer. Our local rep in your area is Tritek
Circuit Products. Their phone number is 714-279-1060. We would be happy
to show you some of our installations. I believe we are the only company
that sells the equipment and well proven chemistry designed to work
together.
If you would like more info please call us or visit our web site at
www.Romartech.com. Our phone number is 978-887-0777
Hope this info is helpful
Date: Wed, 14 Jan 1998 14:48:59 EST
Rogelio,
My question is why are you considering membrane filters? Since the
circulating flow is about ten times the filtered flow, you'll have to have
circulating pumps (one running; one standby) sized for say 500 gpm in order to
get 50 gpm out of the filters. Calculating the cost of electricity, not to
mention the capital and maintenance costs yields additional costs which are not
offset. Our analysis showed that the only cost offset for membrane filters is
the cost of coagulant or flocculent used in gravity settling systems. Otherwise,
everything else cost more - amortization costs, electrical costs, maintenance
costs, floor space costs, etc. Your cost of WW treatment will be higher than a
gravity settling system.
Since properly run gravity settling systems can achieve very low metal
discharge levels, why would you not consider them? We have at least five single
settler systems running and we average 0.5 ppm or less. I'm aware of a dual
system running in series which typically achieves 0.06 ppm!
Lee Wilmot
Date: Wed, 14 Jan 1998 12:24:43 +0000
Rogelio,
I'm sending you a long article of the various types of PCB waste
treatment systems and there advantages and disadvantages in a direct
e-mail. It is too big to attach to this and broadcast.
In short, you need to do some other treatment in front of the RO.
They are very intolerant of dirty water. If you try membrane systems
alone, you will end up with a lot of sludge, some clean water and a
lot of membrane cleaning time. Even the microfilters need a lot of
pretreatment to prevent clogging and the still do. You will also have
to watch the segregation upstream.
Bob Mesick
Reply-To: "ComplianceNet Mail Forum."
Sender: ComplianceNet Mail Forum
From: Charles Barker
Subject: Re: Membranes
X-To: rhorta@MCCURDY.COM
01/13/98 09:42 AM
Some information gleaned from our Culligan Man:
Reply-To: "ComplianceNet Mail Forum."
Sender: ComplianceNet Mail Forum
From: "Erin T. Conner"
Organization: Romar Technologies, Inc.
Subject: Re: Membranes
X-To: Rogelio Horta
Steve Lavalley
ROMAR TECHNOLOGIES, INC.
Reply-To: "ComplianceNet Mail Forum."
Sender: ComplianceNet Mail Forum
From: lwilmot@HADCO.COM
Subject: Re: Membranes
X-To: Rogelio Horta rhorta@MCCURDY.COM
We have one facility which has utilized membrane filters to remove
reactant precipitates from treated WW, but are in the process of replacing it
with a gravity settling system. (Main reason for replacement is increased
capacity.) However, with years of operating experience on these filters, we can
say that it is absolutely crucial that you segregate organic bearing WWs from
inorganic ones. Otherwise, as Steve Lavalley said in his message, you're going
to have membrane pluggage, reduced flow and increased cleaning chemical issues
to resolve. A basic problem is then, how do you treat metal bearing organic
containing WWs when you have membrane filtration?
lwilmot@hadco.com
Reply-To: remcobob@gte.net
Sender: ComplianceNet Mail Forum
Comments: Authenticated sender is
From: Bob Mesick
Organization: Remco Engineering
Subject: Re: Membranes
Remco Engineering
Water and Wastewater Treatment Systems
http://www.remco.com