Hacker News new | past | comments | ask | show | jobs | submit login
Nets on the outlets of drainage pipes save waterways from pollution (themindcircle.com)
154 points by lelf 27 days ago | hide | past | web | favorite | 85 comments

I kayak and fish in the bays of NYC. A fact not known by much of the population of the city is that almost every time it rains, the sewage treatment plants release raw sewage into the ocean. This is due to the storm drains being drained by the same system that sewage is treated from. Due to this the water is filled with trash, floating condoms, and wet wipes. So this isn't just third world countries. It is bad enough that bacteria and nitrogen wastes get into the water when this happens. They should at least capture the trash and disgusting sewage products.

Because this is top comment and no one has provided further explanation yet, here is a link: https://www1.nyc.gov/html/dep/html/stormwater/combined_sewer...

Most older cities have what are called combined sewers (there is a good wikipedia article on it) and have to deal with this problem in various ways.

Not just older cities. I live in San Diego and we have exactly the same problem here. Can't swim or surf after the rain. Not exactly sure why it was done this way - maybe because it rains very rarely and they just did not design the sewage system to handle rare (but sometimes heavy) rains.

California built a ton of great infrastructure and then people decided they didn’t want to pay to maintain it. The entire state is full of projects where the people who ran them are begging for money to avoid needing to spend even more after it finally breaks. One of the big problems was the sprawl due to the highway system – when San Diego raises its property taxes that means people may still work and play in the city but will buy a house somewhere else, paying no taxes at all.

This is a common story around the world but Prop 13 adds the wrinkle that it mostly affects new buyers and people who haven’t figured out how to pass property to their descendants without resetting the tax assessment. That guy who bought a place in PB with his back pay when he got out of the Navy is still paying $100 a year in taxes. He has a massive incentive not to do anything which will reset that, so the city won’t be getting more revenue that way until he (or his heirs) sell the place.

Yup. I had to explain this to my visiting friends, who wanted to go to Coney Island after a storm.

IIRC, there are physical limitations on the city's ability to filter sewage and stormwater -- it all runs through the same pipes, and it would be a momentous undertaking to split the systems (some of those pipes are 200+ years old, and aren't accurately mapped). Wastewater treatment capacity is slowly increasing, however.

They wanted to collect Coney Island Whitefish?

This seems worse in almost every respect than a hydrodynamic stormwater separator. With the latter, you pop open a manhole cover and suck out the goo with a vacuum truck. With a net, you have to somehow pick it up without spilling the contents. Then you hope you can empty it without destroying it or you replace it. This sounds much harder.

Oh, and hydrodynamic separators claim to catch oils, too.

Textbook example of perfect being the enemy of good. If we can't solve the problem 100% with this (cheap, easy to retrofit) method then why even try?

How much do those cost though?

The only benefit I can think of is that it is probably easier to retrofit onto existing installations.

That only works for vertical storm drains, no? Could it be installed in outflow pipes as seen in the pictures?

And what about cost?

Looking around, a number of widths exist for these systems, and installing what is called pre-cast units would start at about 10k$ for the smallest (4ft in diameter), and go up from there (see EPA paper below for additional details). Maintenance costs are said to be really low in what I could find (1000$ a year or so), as maintenance (emptying the trash) can be done by one vacuum truck in 30 minutes. So it may be a better choice for systems that are there to last rather than nets, but nets would still be best for temporary sites. http://www.water-research.net/Waterlibrary/Stormwater/hydrod...

Wet garbage is extremely heavy and hard to clean up. These socks typically require heavy equipment to remove/maintain. These filters also only work well in very specific drain configurations. Not as effective as the article suggests.

I feel like a similar design could be implemented almost on any water way that is small enough, so I don't see how the drain configuration is a limitation. They probably don't want to put them where there might be wildlife, so they would only want to put them in rainwater runoff. This obviously isn't the answer to the entire plastic problem, but it seems to be helping.

What is specific about a circular drain opening for this to work?

I think the answer to this is the same as the answer to the classic interview question, “why are manhole covers round?” With a round hole, a ring of slightly larger diameter (to hold the net in this case) cannot pass through the hole, no matter what angle it gets turned. With any other hole shape (eg rectangular), the “ring” that sits outside the hole to hold the net can be turned such that it can go through the hole.

Strayan here. These nets are used quite widely by a number of local councils including Greater Sydney. They are not universally used though. Larger waterways may have a boom, a number have these nets, some have something like a metal sieve and many have nothing

Some people have suggested a vacuum may be easier. But a council in Australia always has bulldozers and rubbish trucks available, so it may fit better into that existing infrastructure

I wonder why we don't have them at every level.

If we make it legally mandatory to put such a filter in every house then it will often get clogged and cost money and people will learn not to flush down the waste in toilet.

I read somewhere that people learn best when mistakes cost them money.

Imagine hotels having a massive filter then some might want to install sensors in individual drainage pipe coming from the individual units and charge their customers based on the amount of waste they flush down the toilet which ends up costing the money to hotel on subsequent cleanup.

It looks like these are applied to waterways that are largely free of faeces, such as storm drains.

A net applied to pipes intended to transport faeces would presumably need holes so big it couldn't catch condoms, sanitary products or wet wipes.

> Though the installation and the manufacture of these nets cost money (about $10,000 each)

That seems exceedingly expensive for a net and a metal ring to hold it (maybe because drainage outlets aren’t standard sizes?), but I’m impressed with the claims of how effective it is.

The city's website [1] says that cost includes the design, manufacture, install and associated civil works.

[1] https://www.kwinana.wa.gov.au/our-city/news/Pages/City%E2%80...

Plus, it goes on to indicate that's a cost savings over the old "roam around and pick it up by hand" approach.

I though the same initially, but if you look closely there is a metal assembly that has to be fitted to the concrete pipe, plus the whole thing must be a lot heavier than one would assume from pictures to withstand the water pressure for weeks at a time.

Australian. I've seen this circle the internet many times, but I've never seen one in the wild at any beach or river outlet.

These have been over the runoff drains around bondi, tama, bronte and coogee for as long as I can remember (at least 10 years) so I’m surprised this is being reported as ‘new’

I doubt that "Australia" Found a Way is putting credit where it deserves to go. It's not exactly a national priority.

You make it sound like Australia has a huge problem with plastic/trash in waterways that "Australia" is actively ignoring.

In general, Australian's culture is to use rubbish bins and keep things tidy.

Sidepoint: I am not sure if it is something only Australians do, but whenever something about Australia comes up, there will be an Australian there bemoaning how badly we do things. Yes, there is always room for improvement, but Australia is so far ahead of most countries in just about any measure that you choose, that one has to wonder where this sentiment stems from.

It's probably because a lot of people feel we could easily do better when it comes to the environment - regardless of what other countries might be doing.

And there are a number of areas where we certainly aren't ahead either.

Oh I agree that we can do better, and should do better. I am more taking issue at people who make it sound like Australia is terrible compared to just about any other country, no matter what the discussion is about.

Whether the discussion be about environment, politics, innovation, corruption, you name it, some Australian will start moaning about how badly we do X.

I wasn't implying that things were bad in Australia in this case, just that the credit for this net idea could be better given to a specific person or organisation.

I.e., there's no "Australia" program to install these nets, as far as I know.

Fair enough. Apologies for reading too much into your words, and ascribing a meaning beyond what you had intended.

There's a rather fancy one in North Strathfield in Powells Creek at coordinates: -33.8586891, 151.0842781

Not suprising given the article only mentions one city council doing this.

There's one literally fifty meters from my house in Perth, but ok

I assume this can only work for outflows near a road in order to provide access to the machinery. Outflows in forests, and at the foot of cliffs might go uncaptured, but its a good stab at a solution.

In the Thames they have flotsam collectors that rubbish ends up as the tide tos and fros along the river, it's called a passive driftwood collector:


I noticed this one a few weeks back when I was at the shops. There seemed to be a weird crane-line contraption hidden in the woods where I knew there was a creek or canal. Thinking it had something to do with canal boats I wanted to have a closer look. https://goo.gl/maps/FuXrmR7TFRmm4r1r5

It's very much like those carnival crane games where you try to lift a prize out of a glass box. I'm not sure how often it's emptied, but at the time it was full of rubbish.

Seeing as a city reservoir is not far away I can understand why they would want to filter as much as possible before it floats that way.

This is great! It certainly helps but we humans also need to change our behavior about littering.


Interesting, I'm curious about the impact on wildlife and the way they switch the full nets for empty ones. They imply there's an overflow system in place I'd love to know how that works

More info on the company manufacturing those http://stormwatersystems.com/trash-traps/ They also make trash collecting bots boats.

At least one of the pictures shows the nets are on pipes that drain an open cistern. It appears that if the nets get clogged, water will fill the cistern and flow over, bypassing the nets. Seems like a fairly reasonable fallback solution until the nets can be cleared and put back into action. Other pictures show netted pipes that don't appear to have such a cistern, so I do wonder how overflow is handled in those cases - maybe a cistern upstream that's not visible?

Nets on the inlets to storm water systems help a lot too. Leaves, rubbish etc get trapped and collected. I used to see them around building sites here in Auckland, but they have started cropping up in other areas too. It probably makes sense to filter it at multiple points.

this is so damn simple, that I fear for us, for not having thought of it sooner ><

Exactly what I thought first too.

Expected this article would be about the series of tubes know as the Internet of Drains.



Holy crap. I did not realize this much litter came down drains. Insane.

What a weird country, on the one hand they want to save environment from plastic pollution.

On the other one tho.. invest in coal power plants, which will only make drought issues bigger.

Inconsistencies in environmental standards aren't uncommon globally. Even environmental leaders like California have, what I would consider to be, inconsistent water usage policies, even if it does consistently evolve technology to facilitate those policies.

Trust me, a lot of Australians hate the current leadership and would love to see them gone. Unfortunately we are tending towards the trial version of USA.

As the recent federal election clearly demonstrated, the proportion of Australians who 'hate the current leadership' is a lot smaller than previously imagined.

It needs to be more broadly look at than simply election results. We have had notoriously disingenuous governments which have mislead the broader voting population into believing flat-out lies when it comes to the environment, the economy, and the state of society in general. The fact that people voted in a certain direction is only evidence of a successful yet highly questionable marketing exercise.

Ah, yes, the old "the only way anybody could have voted for my political opponents is if they were duped or lied to". Do you realize that people have different political dispositions? And that there are valid positions on both sides of most issues?

Please don't make assumptions over my particular leanings, it's a fairly high-level observation I was making. If you'd like to dispute that the last few governments in the last decade have been increasingly blatant with misleading the public, I'm all ears.

So what if people were lied to? Is the government the citizenry's only source of information? Do they even trust the government? Are there not competing sources of information? What basis do you have for concluding that the Australian government has any significant ability to sway the opinion of its citizens?

You're being directly obtuse, but to humour you:

> So what if people were lied to?

This is fairly serious when you consider that this is the entity which takes a portion of your working income as tax to provide services based on the needs of the community. If the policies which are decided on are based on a misinformed public opinion, then the services which are actually required (as opposed to being perceived as being required) are not delivered.

> Is the government the citizenry's only source of information?

Obviously not, but to claim that there is not a significant perception of truth in a lot of people's eyes when it comes to what a sitting government says is naive.

> Do they even trust the government?

See above, many do.

> Are there not competing sources of information?

This is a discussion in itself. The Murdoch groups own over two-thirds of the media outlets in this country (something like 64% according to a quick glance at wikipedia [1]). It is no small secret that this organisation has a lot of influence in Australia and has swayed public opinions previously on various topics, and there's a plethora of articles discussing this [2].

> What basis do you have for concluding that the Australian government has any significant ability to sway the opinion of its citizens?

I'd put the onus of proof on you for this one, what makes you think that they do not? Governments spend tens of millions of dollars in prime-time advertising with the sole intention of sway opinions of citizens. This seems beyond ridiculous to me that you would want to make that point.

1. https://en.wikipedia.org/wiki/Media_of_Australia

2. https://www.theguardian.com/media/2018/sep/20/very-australia...

> I'd put the onus of proof on you for this one, what makes you think that they do not? Governments spend tens of millions of dollars in prime-time advertising with the sole intention of sway opinions of citizens. This seems beyond ridiculous to me that you would want to make that point.

Look, your point is that the government lies to people and that this influences they way they vote. I’m sure that has some marginal effect. But here you are completely unaffected by these lies. So what’s the difference between you and somebody who votes differently? Is it that they are a hopeless rube who has been taken in? You seem to think so. But you have not demonstrated at all that it isn’t an alternative hypothesis which explains their different voting record. And the alternative hypothesis that I would put forward is that their different political leanings account for most of their different voting record. And that their lack of concern about the veracity of the information put out by the government is a result of these different political leanings, not its cause.

How do you know I even vote?

I could be an expat from another country for all you know.

(Note: This isn't the case, but it well could be. Don't make assumptions. That's why a higher level discussion is better than getting pissy at each other and trying to level attacks - which is what you're doing.)

FWIW, you haven’t invalidated my position. Our disagreement is about the direction of the arrow of causality between misinformation and voting. Whether or not I assumed that you vote and/or are an Australian citizen is irrelevant.

But didn’t the public just vote for coal?

The people I know who voted for the libs preferenced the greens first and only voted for the libs because labor would leave them financially worse off.

And we have to put our own finances before the environment! (Screw our children, after all.)

“The public” just voted in a popularity contest. “The public” doesn’t give a shit about coal.

Unless you live in Townsville, Queensland which currently has high unemployment and a new coal mine scheduled to be constructed nearby.

Yes, that was one of the big distortions of the whole campaign. The mine looks like possibly being an environmental disaster, which isn't great given it's proximity to the Great Barrier Reef - possibility of more coal run-off going into the reef (keeps happening whenever it floods already from the existing coal port), and pollution and physical damage from the extra shipping that will go through the reef area to the port. Then there's the massive amount of water they're going to be allowed to draw from the Great Artesian Basin (which is already depleting at a worrying pace). And all that's before even thinking about climate change.

But the conservative side of politics managed to make it all about jobs, even though the mine, being highly automated, will deliver very little. I believe the most the company expects is about 1600 (even though for years they were claiming 10,000 which still isn't that many). I believe more people have already been employed installing and maintaining renewable energy this year than will ever be employed by this mine, if it ever gets funded (a lot of banks have said they wouldn't fund it because of the environmental problems, as well as the fact that it doesn't seem like it will stack up economically, because the extra supply will likely push down prices making it, as well as other mines in the state less profitable - possibly to the point of unviability).

So it turned into this culture war over coal based on a mine that probably won't go ahead and even if it does won't actually give the community the jobs it needs...

Well colour me pleased that Townsville, Queensland is representative of our entire country.

Australia exporting coal to India and China is far more likely to be having climate change impact than anything it might be doing domesticaly in terms of power generation.

Mining is such a big industry in Australia and has been for such a long time that dirty coal money has influenced the politicians in government for a long time now.

800 pounds in a couple of weeks... kind of dispells the notion that it's not coming from western countries.

800 pounds? China pumps 4,800,000,000 pounds (2.4 million tons) of plastic into the ocean each year.

No, western countries are not perfect. Yes, the vast majority of ocean waste comes from poor, non-Western countries. The US, 3rd largest country by population, is #20 for ocean pollution. China alone produces 1/3 of all ocean waste.


Plastic waste per person is a different story.


USA: 0.34kg per person per day

China: 0.12kg per person per day (just under a third of the US figure).

In cultural terms, China is already far ahead of the USA in terms of individual responsibility.


Edit: Though your point on the handling of waste itself still stands (at least according to 2010 figures)

> China is already far ahead of the USA in terms of individual responsibility.

I would not call it individual responsibility. It’s called poverty.

Western countries export most of their plastic waste to the countries named in the article. Substantial amounts of the plastics China spills into the ocean are ours, exported there for “recycling”

Why does that matter? The issue is that they claim to be recycling and then just dump it in the ocean instead.

That's quite disingenuous to what's really happening. The companies in the US claiming their "recycling" service are probably well aware of what's going on, and China probably isn't making any promises that they're recycling anything. The US companies accept money for "recycling" material, maybe cut off the power cord for reuse, then pay China to take the rest as junk.

And it's a given that if you're transporting garbage to a landfill, some of it isn't going to make it that far and will eventually end up in the ocean. Maybe they are just dumping it as you say, but just the fact that some of it ends up there isn't evidence of that fact.

You contradicted yourself in your own post. If there's no evidence that they're dumping it in the ocean then what exactly are the US companies supposedly aware of?

The fact is that US companies are paying for a disposal service. What that disposal service does is up to them, and if they just throw in the water then it's their fault alone. Maybe there should be some regulations there to ensure recycling companies actually do some recycling.

>what exactly are the US companies supposedly aware of?

That it's not being recycled.

But who puts them into the water?

We ship our low grade plastic waste there well knowing what will happen with it.

A lot of that was probably imported western trash. In terms of trash production I would guess US is way higher. Just a guess though.

This merely puts the plastic pollution somewhere else (into a dump near the ocean most likely), so it doesn’t really save anything.

The problem is still the production of the materials in the first place.

Sorry, that's just ludicrous.

Putting plastic in a dump is much better than letting it kill animal after animal, decomposing into smaller pieces and getting into the food chain.

Ideally we design most plastics out, but barring that recycling would be fine - and just burying it is still much better than either burning or letting it drift into oceans.

Your comment's great, except for the first sentence, which is what the site guidelines refer to as calling names in arguments. Would you mind reviewing https://news.ycombinator.com/newsguidelines.html and editing those bits out of your HN comments in the future?

I know it seems small, but it has a downgrading effect on conversation. Also, it often doesn't seem small to the person being addressed that way (or some other readers who happen upon it).

Thank you for being the net on the outlets of our drainage pipes! Subtle & not unnoticed work.

Of course if we didnt use as much disposable things there would be less trash.

But wouldn't you rather have all this garbage collected somewhere, than scattered throughout the river and beyond?

Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact