PFAS, PFOS, PFOA, PVDF?

Debunking Misleading Connections Between PFAS and PVDF Membranes

There is confusion in parts of the U.S. water industry, possibly fueled by non-PVDF membrane suppliers, around the connection of PVDF membranes and new regulations for PFAS compounds in drinking water. PVDF (Polyvinylidene fluoride) is the most widely used material in the manufacture of MF and UF membranes.

The confusion stems from proposed regulations in Europe that would broadly define PFAS as any substance that contains at least one fully fluorinated methyl (CF3) or methylene (CF2) carbon atom (without any H/Cl/Br/I attached to it). This definition would cover a wide variety of chemical structures, including PVDF. In contrast, the current USEPA definitions of PFAS exclude PVDF including the most recent update of the structural definition of PFAS.

The American Membrane Technology Association (AMTA) has stated that PVDF is considered to be part of a class of high molecular weight fluoropolymers that are distinct from non-polymeric PFAS and have distinctly different physiochemical, toxicological and environmental characteristics. AMTA also states that suppliers of PVDF used for water treatment membranes have certified that there is no use of PFAS as processing aids. See the full AMTA Fact Sheet here.

So, with all of this regulatory discussion there is an ‘opportunity’ to confuse those that are not conversant in polymer chemistry and the correct definitions. I have heard concerns from some end users and engineers that PVDF membranes may release PFAS compounds and may therefore be banned in the future. Coincidentally, these rumors are strongest where ceramic membranes are being considered… Ironically, when offered PES membranes as a non-PVDF polymeric membrane alternative, one engineer said they did not want to consider ‘unproven’ membranes, implying that ceramic membranes were considered more proven... I’d say there are orders of magnitude more PES membrane capacity installed than ceramic membranes, also with a lot longer operating history.

If an engineer and owner want to install ceramic membranes, that is their decision to make. I just want to make sure PVDF membranes are not misrepresented and decisions and made based on facts. Firstly, the European regulations are not being proposed due to any concern that PVDF membranes are releasing PFAS into drinking water. They are just a broad regulation to ban production of products using PFAS materials (like Teflon). Secondly, there is no evidence that PFAS compounds are released into drinking water from PVDF membranes after use for over 20 years. As part of the development of regulations for PFAS in drinking water, the USEPA has required extensive testing of drinking water supplies and no connection with systems using PVDF membranes has been made. Thirdly, the USEPA has indicated it has no intention of banning PVDF or classifying it is a PFAS compound, irrespective of what happens in Europe.

I know some water systems will still lean towards using ceramic membranes due to concerns about future regulations against PVDF even though this is highly unlikely. If they are prepared to pay a high premium for membranes as insurance against this low probability, sobeit. Maybe less expensive insurance would be to install an open platform/universal polymeric membrane system now, that can be converted to ceramic if needed in the future.

The comments and opinions in this post are my own and not those of my employer.

What the Flux! – Part 2

Polymeric vs Ceramic Membranes – Lifecycle Cost Comparison Myths

 

In my last post I discussed that just because ceramic membranes can operate at much higher fluxes than polymeric membranes, a ceramic system will not necessarily have a smaller footprint since ceramic modules or stacks have a lot less surface area than polymeric modules – often less than a quarter the surface area in the same footprint. Therefore, higher flux does not necessarily translate into a lower capital cost.

In this post I will focus on the operational cost comparisons and dispel some myths that ceramic membrane systems have lower lifecycle costs due to longer membrane longevity. Let’s start with the longevity. In polymeric versus ceramic membrane lifecycle cost comparisons, membrane replacement frequencies are typically based on warranty lengths which are often 10 years for polymeric and 20 years for ceramic membranes. A 10-year life for polymeric membranes is OK, but there are plenty of examples of Pall (Aria Filtra) and Toray installations still operating with the original modules after 13-15 years. To my knowledge, only Metawater has ceramic membrane installations over 20 years’ old and therefore can guarantee this lifespan. They say the strength of a chain is based on the weakest link and while I don’t doubt the ceramic membranes used in Nanostone, Ovivo and Cerafiltec systems are very durable and would probably last 20 years, what about the plastic components, polymers and glues used to construct and house these membranes? Will these parts last 20 years? I don’t know if any of these systems have been operating more than 3-5 years so far, so it is taking a great leap of faith in believing these systems will last 20 or more years. The housings on the Metawater modules on the other hand are made of stainless steel, so as long as you don’t drop a module (where it would be like dropping a ceramic pot) there isn’t a weak link to fail before the membranes fail.

 The lifecycle calculations I have seen in bid documents are typically over 20 years, and assume a polymeric replacement after 10 years, and no ceramic replacement over that period, so that is where ceramic systems have an advantage. What if we run the lifecycle cost over 20 years and one day, so we include 2 polymeric replacements and 1 ceramic replacement in the lifecycle cost? That’s fair isn’t it?

 From what I have seen, the cost of a ceramic module is at least twice that of a polymeric module while having around a fourth of the surface area. For a replacement cost comparison, let’s assume the following:

• A ceramic module has 1/4 the surface area of a Toray or Dupont polymeric module (see previous post).
• A ceramic module can get 3 times the flux of a polymeric module.
• A ceramic module costs twice as much as a Toray or Dupont module. Say the polymeric module replacement cost is $2600, Ceramic is $5200.
• Let’s say the base case is a 2 x 2 MGD train polymeric system, design flux of 50 gfd, 45 modules per train. Equivalent capacity ceramic skids will have 60 modules (3 x flux but 1/4 surface area per module).
• Cost to replace all polymeric modules is $234,000.
• Cost to replace all ceramic modules is $624,000.

 Based on the above assumptions, for a 10-year polymeric replacement period and 20-year ceramic replacement period, over 20 years and one day, the replacement cost for polymeric membranes is $156,000 less (two replacements of polymeric versus one ceramic replacement). Maybe ceramics can get a little higher flux and maybe the cost assumptions are a little off, but there is no way you are saving much if anything on membrane replacement costs with ceramics. If ceramic membranes can get four times the flux, the replacement cost is just breakeven using my pricing assumptions.

Known Fact: we know there are Pall and Toray polymeric membrane systems that have had their membranes last 13-15 years. Can we be certain the new ceramic membranes on the block will last 26-30 years to break even with the polymeric membrane replacement cost?

Every water is different, and the flux difference may vary one way or the other to shift the economics, but you can’t say there will be a significant savings in membrane replacement costs using ceramics unless you are looking at the polymeric membranes of yesteryear. Kind of like comparing the fuel efficiency of a car from the 70s with today’s modern cars.

I was going to include a comparison of lifecycle costs with coagulant included, where ceramic membranes often need a coagulant dose to achieve high fluxes, while polymeric membranes do not. This can make the lifecycle cost of a polymeric system significantly lower than a ceramic, but I have rambled on for too long already so will leave that to Part 3.

The comments and opinions in this post are my own and not those of my employer.

What the Flux!

Polymeric vs Ceramic Membranes

My sales rep in the Southeast came to me recently concerned that ceramic membrane companies are promoting fluxes to engineers and water utilities in the region in excess of 200 gfd, asking me how polymeric membranes can compete? My response was WTF! Flux is just a number and just because the flux may seem a lot higher than polymeric membranes it does not mean a ceramic system has a smaller footprint or lower cost. I’ve seen a lot of presentations from ceramic membrane companies trumpeting all the reasons ceramic is better than polymeric but I haven’t yet seen a counter argument from a polymeric membrane company or system supplier. So maybe this is the first counter to some of the ceramic membrane company’s claims. I know I’ll get a push back from the ceramic membrane companies because they are all trying to get established in the market, but I can’t just sit back and let the latest polymeric membranes be unjustly grouped with systems of the past. Note that I am not criticizing the integrity or performance of ceramic membranes at all, and there are situations where these are a great fit, but rather I am just trying to provide a balanced and up to date comparison with polymeric membranes.

WTF!*

Let’s start with the high flux claims. I have seen papers on ceramic pilot studies where fluxes up to 200 gfd have been tested but I don’t yet know of a full-scale system in the US that has been put in service with a design flux this high. The largest ceramic membrane system in the US at Butte MT has a design flux of 69 gfd. A ceramic system that was awarded at Mandaree ND a few years ago had a design flux of 120 gfd for summer. These are pressure ceramic systems where there are feed pumps supplying pressurized modules. 

Figure 1: Membrane System Configurations

The other ceramic configuration is submerged flat sheet operating in the vacuum configuration where a pump draws through the membranes (see Fig 1). Companies such as Cerafiltec and Ovivo are providing this submerged technology and are particularly active in the Southeast. I don’t think a flat sheet submerged ceramic system is installed in the US on a full-scale drinking water system yet, but I have seen several pilot study papers. What strikes me about these recent pilot studies is they are not that impressive. I won’t call out any specific studies, but go search the proceedings from recent AMTA/AWWA Membrane Technology Conferences and you will find them (there may be better pilot studies but I can't find any published). They all spend a lot of time optimizing coagulation ahead of the membranes to reduce rapid TMP buildup and then ramp up the flux in steps over 1 to 2 week periods to get to 200 gfd.  I haven’t seen more than a few weeks operation at anything near 200 gfd in the published papers. Whenever I’ve been involved in a pilot study with polymeric membranes it has been necessary to run at stable operating conditions for at least 30 days. Why is the bar lowered when ceramic membranes get evaluated? Note the Mandaree ND ceramic pilot study did have stable operating periods of at least 30 days at 120 gfd.

 Another criteria for setting design conditions for polymeric membranes is to be a little conservative on the design flux compared to what the manufacturers or pilot studies claim is possible, so if a pilot study shows a flux of 60 gfd is possible based on the feed water quality, the engineer will allow 50 gfd for the full-scale system. While the ceramic membrane companies may claim 200 gfd is possible, when it comes to the design, I haven’t seen more than 120 gfd allowed. Even so, polymeric membranes can be disadvantaged from years of full-scale experience and require a more conservative design flux while ceramic membranes can claim aggressive fluxes without past full-scale experience to suggest otherwise.

 Does Ceramic have a Smaller Footprint?

The claim is often made or implied that due to higher fluxes, ceramic membrane systems have a lot smaller footprint. I will prove to you that is absolute baloney! Let’s look at the comparative footprints of polymeric and ceramic systems. For polymeric, I’m going to use Toray’s HFUG-2020AN module which has 969 sq.ft. of surface area and is probably the most popular polymeric membrane on the market currently. Compare this with a Nanostone ceramic module at 258 sq.ft. per module. A Nanostone module has around the same diameter as a Toray module and is around 9 inches shorter, so the footprint of a membrane rack is the same for both modules (ie. a rack with 40 Toray modules is the same size as a rack with 40 Nanostone modules). Therefore, a Nanostone module needs to have 3.8 times the flux of a Toray module just to have the same footprint based on surface area per module. So, if the polymeric module is designed for a 50 gfd flux, the flux through the Nanostone module needs to be 190 gfd to match the Toray module footprint. If the design flux for ceramic is 150gfd, the Toray system at 50 gfd will have a smaller footprint.

 Now let’s look at a Cerafiltec flat sheet submerged system. These membranes are supplied as 64.6 sq.ft. modules that have a footprint of 28” x 22.7”. Based on Cerafiltec’s website, these modules can be stacked in towers 16 high, so that would add up to a surface area of 1034 sq.ft. From the photos I have seen on the website, the tallest I saw was 8 high, but I will be conservative and compare the footprint of a 16 high tower versus Toray modules in the same footprint. The Toray modules are 8.5” diameter, so within the footprint of the ceramic flat sheet tower, you could conservatively fit 4.5 Toray modules allowing for spacing between the modules (see Fig 2). Therefore a Cerafiltec tower at maximum height needs to have 4.2 times the flux of a Toray module to have the same footprint, i.e. if the Toray module flux is 50 gfd, the submerged ceramic system needs to flux of 210 gfd to match the footprint.

Figure 2: Polymeric versus Ceramic Footprint Comparison

So, I hope I have made it clear that flux is just a number and a high flux does not mean that a membrane system will have a smaller footprint. You also need to consider the amount of membrane surface area that will fit within a given footprint and that ceramic modules have a lot lower surface area than polymeric modules. The price of a ceramic membranes compared to polymeric modules on a membrane surface area basis is also a lot higher, so you can’t assume a higher flux also means a lower cost.

 Of course, there are other important considerations when comparing polymeric to ceramic membranes such membrane longevity and lifecycle cost. I have mentioned in a previous post that the longevity of the newer polymeric membranes is much improved over earlier polymeric membranes which has narrowed the lifecycle benefits of ceramic over polymeric. I’ve also calculated that when you consider the requirement of a coagulant dose ahead of ceramic membranes, the lifecycle cost of polymeric membranes can be lower than ceramic. I will elaborate on that in a future post.

*Shoutout to Stuart Leak from Avista who first used this acronym in his presentation What the Foulant.

The comments and opinions in this post are my own and not those of my employer.

PFAS Discharges into Sand Creek from Suncor’s Denver Refinery Must Stop

Suncor Refinery alongside Sand Creek - Photo by Hyoung Chang, Denver Post

I have been stewing over whether to do a post on an article I saw in the Denver Post on July 27, 2023, regarding discharges of PFAS from Suncor’s refinery in the Denver area into Sand Creek which eventually makes its way to the South Platte.  For years I have been hearing local news stories of concerns from nearby communities about air emissions from the refinery and allegations of exceeding EPA and Colorado Department of Health and Environment (CDPHE) permit levels. I have wondered if Suncor has been given some slack due to its position as a major fuel supplier in the region. Whenever the refinery is offline due to maintenance, etc., fuel prices spike which impacts the wider community’s hip pocket (does anyone keep their wallet in their hip pocket anymore?). Is that allowing Suncor some leverage over CDPHE’s permitting process? According to the Denver Post article, Suncor had been operating on an air quality permit from 2006 that is supposed to be updated every 5 years. The permits for water and stormwater discharges were last updated in 2012.  Of course, having a permit does not mean Suncor adheres to it and there have been reported incidences of benzene spills into Sand Creek over the years as well as air permit exceedances.

South Platte’s PFAS Problem

Being in the water industry and seeing the great expense many water utilities and communities are facing to meet upcoming PFAS regulations, when I read about how such high levels are being discharged from Suncor into a drinking water source used by so many Coloradans it really hit a raw nerve for me. Pretty much any water treatment system taking water from the South Platte in the Denver Metro Area and East, including nearby wells, will have to implement some sort of treatment for PFAS removal. The cost for treatment is in the millions to tens of millions of dollars each, depending on system size. While the drinking water PFAS regulations are still being finalized, many water systems are already making plans to install treatment, since it can take years to get the funds and construct the required treatment equipment (typical solutions are GAC, Ion Exchange or Reverse Osmosis).

Suncor’s source of PFAS is likely firefighting foams used onsite, although I’m not familiar with refining to know if any raw materials contain PFAS also. This contaminates groundwater under the refinery and according to the Denver Post, Suncor treats this groundwater before releasing to Sand Creek, although obviously it not treated for PFAS removal yet. Admittedly, PFAS has only been identified as a concern in drinking water relatively recently (since 2016) and drinking water regulations are still being finalized. But Suncor was issued a draft permit by CDPHE in 2020 to release no more than 70 parts per trillion into Sand Creek. Note in June 2023 Suncor reported to the CDPHE a discharge level of 2,675 ppt…this is after Suncor apparently installed in interim treatment system to reduce PFAS to 70 ppt in early 2022.

The Denver Post article reported that Suncor estimated it would take 3 years and millions of dollars to build a permanent system to remove PFAS from wastewater before discharge into Sand Creek. Suncor also said PFAS removal is extremely difficult and treatment technologies are still in development. These statements really raise my hackles. First of all, established treatment technologies for PFAS are available now – Reverse Osmosis, Granular Activated Carbon (GAC) and Ion Exchange are well proven and already in use for PFAS removal by water utilities. Secondly, if the stormwater is already being collected for treatment, a lot of the hard work is already done and it would not be difficult to add GAC or ion exchange to the treatment train. Much larger treatment systems have already been installed on contaminated Californian ground water supplies in a quick response to the detection of PFAS and the interim regulations. So don’t try to say the technologies are not yet developed! Locally, there are also treatment systems installed at water utilities south of Colorado Springs where they detected PFAS in the ground water supply originating from a local military base.

While Suncor continues to discharge PFAS into Sand Creek, communities downstream are paying the price with their health and their money where the local water treatment plants must pay for treatment.

The article in the Post was written in late July, so Suncor may very well have accelerated installing treatment for PFAS removal since then, since the media is quick to report a violation but often slow to report on a resolution. If so, then I retract some of my vitriol for Suncor not taking action.

The comments and opinions in this post are my own and not those of my employer.

“So your saying there’s a chance” - Dumb Bid Evaluation Processes

 I saw a bid evaluation process recently for membrane equipment that I hadn’t seen in about 10 years. I thought this type of evaluation had seen its last days with the demise of the bids that only allowed the ‘big-three’ proprietary system suppliers (Pall, Memcor, Zenon). I guess there are some engineers/owners still living in the past who don’t realize that bidding processes of the old days are not relevant for evaluating between todays’ membrane system suppliers (MSSs).

This particular bid process required bidders to provide in one envelope (#1) a technical proposal, including qualification and experience criteria, and in the other envelope (#2) the pricing and other commercial information. The owner and/or owner’s engineer would review the technical proposal and select the best qualified submission and only open the pricing proposal for that bidder. If the price met budget they would start negotiations to award to that bidder without looking at pricing for any other bidders. Out of the four MSSs invited to bid, one of these was one of the big-three and would clearly have the most references and be chosen as having the best score out of the technical proposals. So why would the other three bother bidding? Maybe some would hope the favorite in the race did not turn up for some reason?

In the old days, the big-three would bid nearly everything to try get market share in a fast growing and evolving market. Well hello, the MF/UF market is now quite mature, MSSs are often bidding with the same membranes supplied by independent vendors and decisions on whether to bid or not are based on whether the project can be profitable rather than buying market share. So, if you don’t have an open and fair bidding process, there may be only one bidder, which does not look good for the writer of the specifications.

This bidding situation had the look of the engineer/owner really wanting to select one manufacturer while keeping that manufacturer’s price honest. As long as the price is within budget, that manufacturer’s price could be higher than all others and the owner would never know. These days for MF/UF system procurement it is common to see a prequalification stage where a short list is made of manufacturers based on experience, company financial stability, references, local service, etc and then these bidders have a competitive bid based on price. That way the owner and engineer are happy with the quality of the bidders and the owner gets the best price from these bidders.

Another bidding process that is a combination of the above has a scoring matrix where price (or NPV) is say 40-60 points out of 100, with the rest of the points spread across reference installations, local service capabilities and other factors. This evaluated bid process can still allow the engineer/owner to pick the MSS they prefer using the subjective scoring factors, as long as the pricing of the preferred vendor is not too high. But at least all bidders will get their prices considered and therefore more MSS’s will likely bid, even those scoring lower on the non-price factors. As Lloyd said in Dumb and Dumber “So your saying there’s a chance”. I still think this bid process is not ideal, but if it is an open bid with no favorite, I’ll take this this type of evaluated bid over the two-envelope lucky draw...

Of course, if I am in the shoes of the preferred manufacturer with the best experience, I’ll take the ol’ two envelope bid process but sooner or later when this process yields only one bidder, somebody will end up looking dumb…

The comments and opinions in this post are my own and not those of my employer.

Gasson Spices up Membrane Technology Conference Opening Session

(Not one of the keynote speakers)

This year’s Membrane Technology Conference (MTC) in Knoxville TN, February 20-23, saw a spike in attendance, almost back to pre-covid levels, with a definite buzz around the presentations and exhibit hall where attendees were excited to be back networking with colleagues and technology suppliers.

Christopher Gasson, Publisher of Global Water Intelligence, was a keynote speaker for the Opening General Session, along with Harry Seah, CTO of PUB. Christopher’s ‘State of the Global Membrane Industry’ presentation certainly provided a spicey opening to the conference with his description of ‘What’s Hot and What’s Not’. Some exhibitors in the audience that were on Christopher’s ‘Not Hot’ list may have begged to differ. These included manufacturers and developers of ‘Fancy Membranes’ which I assume referred to new chlorine resistant membranes and fouling resistant membranes among others. From a global market share perspective, he is probably correct, but companies such as ZwitterCo are likely not trying to take the place of traditional RO membranes and are content targeting niche markets.

Other technologies or technological trends on the ‘Not Hot’ list included higher recovery for seawater, higher flux RO membranes and lower pressure desal membranes.

On the ‘Question Mark’ list included ceramic membranes and Universal/Open Platform low pressure systems.

During questions, Hary Seah agreed to disagree on the potential for ceramic membranes where PUB is a big advocate of ceramic membranes at its plants in Singapore. I’ve given my thoughts on the ceramic market previously and copped some flak for saying it is a niche technology, but I would agree with Christopher on his position.

I also agree that the Universal/Open Platform low pressure market may have cooled a little now that there are many direct replacement modules available for Asahi (Pall), Memcor, Toray and Dupont modules, which gives some flexibility for future membrane replacements without needing a membrane rack to accommodate modules of different configurations. Also, the proliferation of non-proprietary MF/UF systems using modules from Toray, Dupont and others has taken some steam out of the need for Universal racks. I will flesh this out further in a separate post.

 On the ‘Hot’ list were higher recovery RO in industrial applications (not seawater) which I assume is technologies such as CCRO, Pulse RO and FRRO, polymeric NF (NX Filtration), RO/NF membrane spacers, brine mining and digital monitoring (AI). Christopher pointed out that NX Filtration is capitalized at over €500M with revenues of €8M last year, having investment characteristics of a start-up tech company and a lot of pressure to perform.

I must admit I haven’t been to many opening sessions at MTC, but this one was very well attended, possibly in anticipation of the speakers’ topics. The audience was not disappointed, and Christopher’s thought-provoking statements provided a great catalyst for discussion afterwards and set the stage for a very lively conference.

The comments and opinions in this post are my own and not those of my employer.

Good Projects Spoiled by Bad Contractor Selection

 

Something that really perplexes me is how engineers and owners can put so much effort into the design of a plant, ensuring equipment vendors and components are well qualified and tightly specified, then the project is put out to bid and awarded to the contractor with the lowest price. Then it is a crapshoot if the contractor has the experience or capability to complete the project….

The contractor is the most important part of the project. They are responsible for taking the process equipment specified and all the surrounding infrastructure and turning it into a functioning water treatment plant. So why are there so many instances where unqualified, low-bid contractors win these projects?

When an incompetent contractor runs into trouble with schedule or budget when he/she missed something in the specifications, he is going to do what he can to deflect the blame to try keep the project profitable and avoid LDs. That often ends up in conflict with process equipment vendors to improve schedule to make up for poor project management, and drawn-out payments to vendors because the contractor can’t get approval for achieving project milestones. So many times I have heard the excuse from contractors that they can’t pay for start-up because they haven’t been paid for the practical completion milestone. That is compete BS when the equipment has been delivered and started up months ago and the contractor can’t get his s - it together to finish the landscaping or install the toilets… Just as frustrating is when start-up is delayed for months because the contractor is behind with installation, meanwhile the component vendors for the process equipment must be paid, so we go back to the old story of the process equipment vendor also acting as a bank for the project… (see previous post). All of this leads to conflict between the owner, engineer, contractor and OEMs and nobody feels good about the project.

Don’t get me wrong, I’m not out to bash all contractors. I have worked with a lot of very competent water treatment system contractors. And process equipment vendors are not always without blame for delays and missing items in the specifications. I have also seen specs where it wasn’t clear who was supposed to provide some items, so nobody had them, which is on the engineer who wrote the specs. My gripe is really with the process of not prequalifying contractors and ending up with a rudderless ship of a project. Similarly, process equipment vendors should be pre-qualified and most of the time they are, but when they are not it opens up the possibility of any garage integrator throwing in a price. Which takes me back to my original point – why spend so much time designing and specifying a plant and then leaving the execution in the hands of a random low bidding contractor?

Don't Blame the Pandemic

Admittedly, these days in some cases it has been hard to find contractors to bid projects. So, standards may be lowered to get competitive bids. Before a job goes out to bid, there has to be an awareness of what else is bidding locally that will cause contractors to pick and choose what to bid. I have seen bids delayed so as not to overlap with a larger project bidding in the region, which is smart. I have also seen cases where a bid is due just before a board meeting to approve the winning bidder, so there is no room to delay the bid for scope clarifications or to allow contactors more time to prepare, so bidders drop out. This happens so many times. An engineer spends a year or more pulling the spec together then allows 4-5 weeks for contractors to get a bid together and there is no flex in the bidding schedule to give contractors a few more weeks. Not smart!

 While recent years have made this situation worse with supply chain delays and a shortage of contractors to bid projects, unqualified contractors winning water treatment projects has been going on for years and is not a symptom of the pandemic. Engineers and owners need to put more thought into  the bidding process to ensure they get a competent contractor which will ensure a much more successful and harmonious project for all involved!