Where can I find someone to design a Slow Sand Filter?
August 26, 2016 1:33 PM   Subscribe

Hi guys, I am building a slow sand filter to purify captured rainwater. I have advertised here and on reddit for an experienced engineer to design a filter for me. Where can I go to get more visibility for my request or what should I do to motivate interest in my project?
posted by metasluggo to Technology (20 answers total) 1 user marked this as a favorite
Why are existing designs not adequate?

The CDC has some good info:
http://www.cdc.gov/safewater/sand-filtration.html , including further links.
posted by at at 2:13 PM on August 26, 2016 [2 favorites]

Response by poster: I am not an engineer, but I have read over the design documents, corresponded with a guy on youtube who promotes slow sand filters and asked questions on the forum that he runs. I have tried to do as much as possible myself. Due to numerous design consideration such as available space, turbidity and plumbing issues I am finding that the required design exceeds my skills. Normally when this happens you get an engineer.
posted by metasluggo at 2:29 PM on August 26, 2016

You get an engineer by phoning up an engineering firm and hiring one.
posted by clew at 2:53 PM on August 26, 2016 [3 favorites]

Response by poster: I have had a good dozen phone calls and even had people sit on my couch and tell me they want to help me but they never seem to be available when I call back. I didn't realize I needed to "sell" my problem to people who do this for a living. I guess they have more customers than they need.
posted by metasluggo at 3:19 PM on August 26, 2016

Much like home construction contractors, when the market is hot and there are a lot of available projects then smaller projects are less likely to get picked up. If you ask someone for a quote and schedule on a project, they'll have a harder time dodging you--they either will or won't take your project.

Depending on where you live, this might be against code (we can't filter rainwater where I live, even though we can get a variance to collect rainwater in a cistern or barrel if the outflow is properly set up to enter the sewer).
posted by late afternoon dreaming hotel at 3:27 PM on August 26, 2016 [1 favorite]

If I wanted a new pair of jeans, there's no ad I could write on Reddit or anywhere else that would stimulate someone from The Gap or Levi's to call me up and offer to sell them to me.

If you're a municipal government building a new water treatment facility and hiring someone for five figures or more, then yes, qualified engineers will bid on your project. But most engineers don't have the time to waste looking at random websites on the off chance there's a request to help a homeowner who is interested in the minimum possible job.

Call (or email) an appropriate engineering firm in your area.
posted by Homeboy Trouble at 3:36 PM on August 26, 2016

Response by poster: Yeah. I called lots of them. The last one was a condescending Architect/Engineer ( A specialist in environmental design ) who told me that collecting rainwater was stupid and had I considered building an extension on my house? What I am looking for is tips to get someone knowledgeable interested in what ought to be a pretty hot topic right now.
posted by metasluggo at 4:12 PM on August 26, 2016

Try a fabrication shop. They ought to have plenty of in-house engineering wisdom and be used one-off project constraints and budgets.
posted by glibhamdreck at 4:15 PM on August 26, 2016 [1 favorite]

I know _nothing_ about this or hiring engineers, but here's an idea anyway (I have had experience dealing with people who wanted to hire me for small projects that I did or didn't want to do):

Is there any way you could find people in your area who have done similar projects, then get referrals or advice from them? If there's an engineer who has previously solved a similar problem near you, it may be easy for her to adapt the previous solution to your circumstances.
posted by amtho at 5:42 PM on August 26, 2016

I'm going to guess that it's got more to do with liability -- slow sand filters are certainly better than nothing, but they are not guaranteed to be 100% safe to drink from. And depending on the method of capture, you could be at serious risk for pathogens and other contaminents (see #16).

If you have someone build this for you, then drink from it and get sick, they are at risk of being sued or even facing criminal charges.

The fact that you mention turbidity is not a great sign -- this means you don't have a clean capture and will need a roughing pre-filter anyway, but also that you are much more likely of your water containing something nasty that won't filter out.

Proceed with caution, please. Rainwater is a great resource and you should use it if you can / are allowed, but maybe not for drinking. (Do you have a garden you could water instead?)
posted by ananci at 7:15 PM on August 26, 2016 [3 favorites]

Call your local municipality or government, tell them what you want to do and ask for permit requirements and if they can recommend someone or if they have standards or guidelines. Best way to get a qualified person for a niche thing like this. Failing that go to Mother Jones or the Homesteading forums and ask there. You'll almost certainly need an ozone filtration system or similar too btw.
posted by fshgrl at 9:14 PM on August 26, 2016

Response by poster: You know, this is the response I get all the time:
"You sure are stupid to want to capture rain water! That stuff is dangerous! Just build it yourself, It's easy! Just call an engineering contractor!"

My father grew up drinking nothing but captured rainwater. My whole extended family drinks, baths in, and cooks with nothing but rainwater. None of them have ever bothered to filter ordinary rainwater, so I'm going a step above and beyond.

How is it that one of the key elements of environmentalism ( water reuse and appropriate use) has become something to be frightened of. Do you know that if you live in a major city there is a fair chance that your drinking water was filtered with a slow sand filter? Do you question the purity of your drinking water?

Why am I having to defend myself? Do you not like environmentalism? Why is every part of this a struggle?

I'm thinking of a kickstarter to make a movie highlighting my plight so that leftist engineers can see it at sundance :-/
posted by metasluggo at 3:14 AM on August 27, 2016

Mod note: Everyone, let's stick to the question going forward rather than getting into more back and forth about if it's a good idea. OP, please just flag comments if you feel they are not helping with the problem.
posted by taz (staff) at 4:00 AM on August 27, 2016

It appears that there is a disconnect between how you feel about the project and how people who do engineering for a living feel about it, at least in the current market for engineering projects in your area.

If all the people you have called/had over do not want to proceed with the project it is simply not a commercially viable project for them at the moment. Maybe they'd have to forego other bigger projects, maybe they realise that your specific set-up is likely to give rise to all kinds of problems that would require a disproportionate amount of time to overcome, maybe they feel that they can't do it for what you'd like to spend - it could be none or all of this but at the end of the day they don't want to proceed.

So you can either spend time working out what the problem is and if you can fix it or target your search elsewhere. In particular do you know any retired engineers? Somebody who has the technical expertise and experience but no longer the same commercial and time constraints. Also, engineers in any environmentalist communities may at least be able to point you, even if they can't help you. And these communities are also likely to contain people who had this work done and could refer you. Good luck!
posted by koahiatamadl at 7:15 AM on August 27, 2016

A key question is whether or not this is legal where you live. If it isn't (or if the regulatory barriers are so high as to be insurmountable), no licensed engineer will put their name on the design. You can still DIY it, of course, but this may explain why local engineers aren't showing much interest.

If it is legal, but just unusual, then you have the problem that they won't have an off-the-shelf design to use, so you are in for a lot more cost. I don't know what engineers bill at where you are, but here you could easily pay $150/hour, which includes the time driving out to look at your site, time researching designs and regulations, time assisting during construction, etc, and can add up to real money pretty quickly. A sole practitioner who takes on small and oddball projects would be the cheaper option, rather than a larger firm.

Having said that, there are a lot of existing designs for small scale rainwater catchment and filtration that have been developed for international development projects, and repurposing one of them is likely going to be your best option. (Engineering in Emergencies: A Practical Guide for Relief Workers, which can be easily found online as a pdf, has both drawings and design details for this, for example.) If you can find someone who has done engineering water projects for organizations like MSF, they might have the most familiarity with these kinds of small-scale designs, compared to someone who designs municipal water systems.
posted by Dip Flash at 7:51 AM on August 27, 2016 [1 favorite]

Response by poster: Thanks for taking the time to look at my problem.

In answer to your questions:
*) After a legal battle, environmentalists have gained the right to capture rainwater from roofs in this area. It is still illegal to drink or bath in rainwater here, but you can water your garden, wash cloths and flush your toilet with it.
*) despite the fact that the town that I live in promotes rainwater capture on their website and the local stores carry cisterns in the gardening section, It seems to be so unusual that none of the dozen or so plumbers, engineers and architects I have spoken to have ever set up a rainwater capture system.
*) I have not even bothered to call any of the bigger outfits. They are way out of my range.
*) Our site has many problems that might be discouraging to an engineer who was serious about completing the project, but they never get to that stage. I get that sinking feeling when I answer the door and see a guy who shows up without a paper and pen. They are simply not interested in my project. It usually doesn't even get that far. In general they don't return my calls.

After thinking about this for a while it seems rational and even possibly a good idea to discourage people from doing things out of the ordinary. People in the construction trade have a vested interest in creating a cookie cutter "retail" experience for the public. This insures that people walk away more or less happy with the end product and keeps them coming back. I have read about the nightmare of the Earthship community. They were declared an illegal subdivision and spent years and literal fortunes bringing the Earthships up to code. Earthships by the way, use commercial water filters to filter rainwater. These need to be changed out every few months. I think this is because slow sand filters would freeze in the winter if kept outside and smell like sewage so would be unsuitable for indoor use.
posted by metasluggo at 9:01 AM on August 27, 2016 [1 favorite]

After a legal battle, environmentalists have gained the right to capture rainwater from roofs in this area.

Those guys! You need to call those guys. (Guys = women or men). Tell them what you want to do, and they will probably be not only sympathetic, but informed. Look through the news articles about this effort to get names.

If these people are already your friends, all the more reason to contact them with your question.

I realize they may not be filtering as you want to, but they might still have an idea of who to call or what to do next.

Yes, this is hard. That's not surprising.
posted by amtho at 10:23 AM on August 27, 2016 [2 favorites]

Where are you located? And are you contacting contractors that specialize in rainwater filtration systems? You should reach out to the contractors, not the engineers; contractors will have their own in-house engineering team or will work with an engineer they know.

I've worked with a contractor to design a rainwater capture and reuse system; it was their expertise. This was in NYC; your mileage may vary.

Lastly, to be brutally honest: if you're talking to contractors/people who specializes in rainwater filtration, and none of them are calling back, it either because it's outside of their expertise, or they think you'll be a bad client. This might be any of the following reasons:
1) You're asking for work upfront without payment.
2) Your scope is unclear or vague.
3) They don't think the project is real.

Your comment about "a guy who shows up without paper or a pen" makes me think that you may be expecting something for free. "Can you just tell me what kind of system I need so I can decide whether or not I can pay for it?" equals 'can you design my system without payment?'
posted by suedehead at 5:21 AM on August 28, 2016 [2 favorites]

Response by poster: Look, I have gone a long long way towards setting this up. I have a tiny space here, but I have built a concrete cistern and a space under where I park my car to hold the filter. I have had a lid built by a metal worker that I can drive on and that opens with springs. I put in plumbing pipes into the house and bought a prefiltration system( a swirl filter). This has all taken literally years and put me so far beyond budget that I don't want to even think about it anymore. I have done a great deal of this work myself, but the plumbing is code work and I had a plumber put in the pipes. It should be obvious that I am deadly serious and that I have both the money and the time to complete the project.

If you interpret the fact that professionals show up without a pen and paper as evidence that the problem is ME... well I don't know what to say.

I tried to get at what I think the problem was up above. Let me take another stab.

Engineers occupy a very odd niche in our world. The job of the engineer is not well defined. If you ask a plumber to put in a new hot water heater he will bill you and put in a new hot water heater. When he walks away the job in done. Everybody agrees and that is ( usually) the end of it. When you ask an engineer to design something it is not guaranteed that the result is possible. I think that pure engineering is a non-starter for the average Joe. They have requirements such as:
*) it needs to fit under the car.
*) it needs to use almost no power
*) it needs to not smell bad.
*) it has to filter the water quickly but not so quickly that some of the pathogens can pass through.

and on and on. Some of these things might ( or might not) be possible simultaneously. An engineer has to concentrate on areas that will result in zero customer problems. If he or she has an angry customer he or she can spend the rest of his career debugging the work that he designed. The engineer is also on the hook for the project even if the mason doesn't follow his design. Some people manage to connect but I think they are good salespeople. That is to say I think that folks that need to have something designed are good at getting people to do what they want. Overcoming this resistance is a skill. You look at engineering firms and you think it is like going to the grocery store. It is more like trying to pick someone up in a bar.
posted by metasluggo at 7:36 AM on August 28, 2016

I actually used to work at a place that "qualified" clients before talking to them. We designed products/devices, and sometimes people would call up with an idea for an invention, but the people wouldn't seem to be good clients. My boss gave me a long talk once about "qualifying" people. It wasn't engineering as you describe, but more computer/electronic device/industrial design stuff, but maybe I have some kind of insight.

Here's an idea: hire someone to "coordinate" the project, and have that person start as go-between for you and the engineering firm. An experienced person could help smooth out the communication between you and the engineering firm -- communication with inexperienced people can be _excruciating_, slow, and lead to a lot of wasted work, and that's not even accounting for the increased time/cost (which you would cover, but that doesn't make up for the pain of explaining everything and doing work that gets thrown out). I'm not saying that you'd need this, necessarily -- it sounds like you're pretty clear about what you want and the limitations of your situation, so you might well be a "good" client.

However, just _having_ an additional person with you when you approach a firm, one who clearly knows the field and is really really good at communicating with engineers and with you, could help them relax and maybe even get excited about the project. Plus, a good communicator might help make the project more attractive to them somehow -- he or she might know an angle to the project that would be particularly appealing to the firm, like the possibility of trade journal or news article.

I'm not saying I've witnessed this exact thing, but avoiding the "lone eccentric" stereotype will help a _ton_, and having another person involved in the project could help a lot practically. Also, if you have someone in your employ (who isn't a relative or preexisting friend), it shows that you're serious about the money, too.

I don't know exactly how to find such a person. Maybe a super green remodeling firm, or someone studying engineering, or a professional technical communicator. Maybe someone on Metafilter would have a better idea.
posted by amtho at 11:21 AM on August 28, 2016

« Older Music for Dancing Grammas   |   How Would I Promote a Crowdfunding Campaign? Newer »
This thread is closed to new comments.