Compost Toilet : Our response to water scarcity?

Compost Toilet : Our response to water scarcity?

Let us introduce the newest addition to our production center in Porto: the compost toilet! Although human waste is a taboo subject, we will be talking about poop a lot in this article. After all, if you refuse to address a topic, how can you challenge the conventional and unsustainable systems that surround it?

One unsustainable aspect of conventional toilets is water. Most toilets in wealthy countries use potable water to flush toilets, but water is a resource that is becoming scarce amid rising global temperatures. [1] [2] Even if this were not the case, the fact we contaminate drinking water on purpose reflects a dire need to challenge this convention. Human excrement, ironically, is a valuable resource. It can be used as a source of food for bacteria. Sewage, as well as diseases linked with fecal contamination of the environment, can be eliminated when composting is adopted as a sanitation method.[9]

In our phytodepuration article, we explored one alternative method for wastewater treatment. It consists of a marsh-like condition, in which greywater and blackwater are filtered and purified using plants. Compost toilets are the inverse; they require no water and use dead plants rather than living ones. Essentially, microbes break the waste down into humus, a completely decomposed organic material. Besides feces, the other necessary ingredients for composting are straw, sawdust, dead leaves, or wood chips. These carbon-rich materials are known in the composting world as “browns,” while the nitrogen-rich feces make up “The Greens.” The balance of browns and greens is crucial to successful decomposition; a composting toilet without carbon-rich material would not result in compost and would be a health hazard. Additionally, the browns act as a cover material to expunge smells.

Across the world, different prototypes of compost toilets are being tested within diverse capacities and contexts. One such example is the project Mobile Dry Diversion Toilet in Lagos developed by FABULOUS URBAN with several partners since 2017. The project targets families in low-income communities who do not have access to domestic sanitation. This prototype separates the urine and feces into different compartments, which finally facilitates the process of composting. [4] The urea present in urine degrades into ammonia while not only has an off putting smell but also is the reason for the extermination of the bacteria that would otherwise break down the waste.[5] For further explanation, you may follow the link to the original article. Mobile Dry Diversion Toilet

Mock-up prototype being constructed to be tested for the project Mobile Dry Diversion Toilet Photo. © FABULOUS URBAN

Public acceptance, regulations, and a lack of expertise and experience in composting toilet design and operation are all obstacles to the use of composting toilets in urban environments [3].

We have been testing our system here at the Critical Concrete office.


a large compost pilea toilet chambera bucket within the chambera seat for the chamber

The assembly of components of the our compost toiletTo use the compost toilet, users cover their poop with a layer of carbon-rich material. In our case, this is mostly sawdust because it is a waste material that we always have on hand. Once the collection bucket in the toilet is full, we empty it into the outdoor compost pile dedicated solely to the compost toilet. The fresh layer of waste is covered with more sawdust, which immediately removes the smell and wards away flies. We then rinse the bucket, pour the rinsing water on the compost pile to help moisten the compost pile, and cover the compost pile again with fresh sawdust.

Our compost pile setup

We use our compost primarily for feces as we are an office which means the usage of this toilet for urine will be more than feces. The imbalance of the proportion of urine and feces could result in a slower composting process. A low level of urine is not an issue for the decomposition, but with our compost pile located near our living space, we want to avoid the smell that it can cause. In the active compost pile, the waste completes its conversion into humus. The temperature at the core of the active compost pile can reach upto approximately 650C. The covering material such as saw dust, hay, weeds, straw is referred as biological sponge in the figure on the right. Once the compost pile is high enough, we leave it to cure for oneyear, after which it is safe to use for gardening. The curing time for compost containing human waste is longer than most compost piles, but it ensures the extermination of pathogens present in the feces before its use.

Section through the compost pile © The Humanure Handbook: shit in a nutshell

Temperature reading from our active compost pile

Making a functional compost toilet can be challenging, so of course, we had to manage some difficulties.  First, the volume of our waste output is disproportionate to our available yard space. After just three months of using the toilet, the compost pile is half-full. Since the active compost pile still needs to be cured once it is ample, we may have to pause our use of the compost toilet at that point. If we had unlimited space in our yard, we would have had the chance to start a new compost pile. But in an urban setting like ours, that is not an option. Our second challenge is that our active compost pile is dry because we use a lot of sawdust. In order to create a hospitable environment for the suitable bacteria to break down our waste, we need to add moisture to the pile. At this point having some levels of urine present in the compost pile would help but, we use some greywater from washing dishes instead in order to avoid washing drinking water and unpleasant smell of urine. It will be also good to mention that according to “the Humanure Handbook: shit in a nutshell” by Joseph Jenkins for a household the separating urine and feces is not necessary.[9]

Rich fertile compost

Even though there are some obstacles to using a compost toilet, especially in an urban environment, the system is quite simple overall. For us, it is a way to transition from relying on a flush toilet and better our water usage while producing garden material. We will update our progress on this blog and our social media as we adapt to this new and improved option for human waste management in our headquarters.

Do’s and Don’ts © The Humanure Handbook: shit in a nutshell



[1] United Nations, “Scarcity | UN-Water,” UN-Water, 2011.

[2] E. Saner, “The no-flush movement: the unexpected rise of the composting toilet,” The Guardian, Dec. 09, 2019.

[3] C. K. Anand and D. S. Apul, “Composting toilets as a sustainable alternative to urban sanitation – A review,” Waste Management, vol. 34, no. 2, pp. 329–343, Feb. 2014, doi: 10.1016/j.wasman.2013.10.006.

[4] “Mobile Dry Diversion Toilet FABULOUS URBAN,” Swiss-Architects. (accessed Oct. 06, 2021).

[5] N. Rogers, “Composting toilets could be the way of the future,” ABC News, Jun. 24, 2019.

[6] T. Avellán, “The world needs more toilets – but not ones that flush,” The Conversation, Mar. 21, 2017. (accessed Oct. 07, 2021).

[7] “Saving water in the home,” nidirect, Oct. 20, 2015.

[8] N. Hancock, “Safe Drinking Water Foundation,” Safe Drinking Water Foundation, Nov. 30, 2016.

[9] J. C. Jenkins, HUMANURE HANDBOOK : shit in a nutshell. S.L.: Chelsea Green, 2019.


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Interview: Why Krytonite™ Is the Unsung Hero of Construction Joint Waterproofing

Interview: Why Krytonite™ Is the Unsung Hero of Construction Joint Waterproofing

When you think of general concrete waterproofing, you probably envision membranes or crystalline waterproofing admixtures. But those aren’t the only aspects you need to consider for waterproofing. In fact, you should think of them as part of a more holistic approach to waterproofing. With only membranes or concrete admixtures, you’re not protecting your entire structure from water ingress. You’re missing out on protection for areas like tie holes, pipe penetrations, construction joints, and control joints.

It only takes one of those areas to remain exposed to water for there to be a water ingress problem. After all, as the Construction Waterproofing Handbook notes, 90% of water ingress issues happen within only 1% of the total structure’s surface.

That’s why you need solutions like our Krytonite
Swelling Waterstop, which seals concrete construction joints, protecting them from water. Such solutions, however, aren’t always given the attention they deserve.

To see why that is and why changing that in favor of Krytonite and more is better, we’ve turned to our territory manager for the Eastern United States, Christian Warren. With over 13 years of technical territory sales and operations management experience in concrete waterproofing construction and a background in ready-mix quality control, Christian knows just how valuable it is to give each concrete detail its due. And it’s why he’ll be discussing the value of Krytonite with us today.

Thank you for joining us here, Christian. While all aspects of waterproofing are necessary, waterstops like Krytonite are not often the first part to come to mind for builders. Why is that?

Thanks for inviting me.

As you mentioned, waterstops tend to not get the spotlight that’s needed. As they’re encased inside concrete, it becomes easy to forget about them (it’s like the old saying goes: “out of sight, out of mind”). That’s the case for both waterproofing successes and failures.

Successes tend to be attributed to the whole waterproofing system. And failures are no different. In either situation, it’s difficult to diagnose the waterstop’s successful contribution to the waterproofing system because it takes destructive techniques to the concrete joint to even see the waterstop’s condition.

What about Krytonite itself? What makes it stand out from the other waterstops on the market?

While the installation of Krytonite will be familiar to those who have installed bentonite or other swelling waterstops, the performance of the product is top-level.

For performance comparison, bentonite waterstops offer entry-level capabilities. They’re often inexpensive and mostly ineffective, even in low-risk applications. Part of that is due to their uncontrolled swelling and inability to hold up through wet-dry cycles. Because of that, there is a risk of the concrete blowing out due to high internal pressures, damaging the structure and incurring high maintenance costs as bentonite waterstops deteriorate quickly due to their clay-based composition.

Meanwhile, Krytonite offers greater performance. It’s designed with advanced elastomeric hydrophilic polymers, which is a superior form of technology to that of bentonite. As a result, Krytonite offers better compression sealing, stability, and longevity.

For compression sealing, Krytonite can swell more than 10x its original size. That is up to 4x more than competitors. And with its unique trapezoid shape, Krytonite can minimize the possibility of voids in the concrete.

For stability, Krytonite takes advantage of controlled swelling that allows for proper concrete strength development. It also ensures that Krytonite will never blow out the concrete due to unchecked internal pressures.

And for longevity, Krytonite is made to be cohesive, remaining intact for the life of the concrete structure. It’s a stark contrast to bentonite waterstops, as those are expected to disintegrate eventually, especially under extreme conditions and constant wet-dry cycling.

Of course, the greater value with Krytonite is not just the top-level performance but its cost and warranty. How Kryton has priced it and given it a 10-year limited warranty makes this waterstop a huge value add. It ensures that contractors can get guaranteed top-level performance for entry-level pricing with Krytonite.

So, Krytonite comes with great performance and value. A significant factor for the performance side of things seems to be the product’s superior swelling. Just how does that work? And for how long?

So, Krytonite will swell only in the presence of water. Depending on that water’s source and where the Krytonite is situated, contractors will see variations in that swelling. For instance, to see Krytonite swell up to 1,000% of its size, the waterstop would have to be unconstrained and come into contact with clean water. But when it’s placed within a joint, Krytonite will only expand as much as necessary. So that means expanding until it has enough pressure to stop the flow of water.

Krytonite will stay that way so long as there is water present.

Can it seal more than just construction joints with this ability?

Yes, you can use Krytonite to seal around other items fully embedded in concrete. These might be pipes, studs, or tie rod sleeves.

Is it able to withstand water contaminated with salts, acid, or hydrocarbons?

Whether the water has salt, acid, or hydrocarbon contamination, Krytonite will still be able to activate and operate as normal. It’s all thanks to its unique synthetic rubber technology. Because of the technology’s cohesive properties, Krytonite will not deteriorate if it encounters contaminated water.

Still, to maintain quality, I recommend that contractors confirm the Krytonite’s stability with Kryton’s technical department if the contaminated water levels are particularly high.

How do you get Krytonite to adhere to concrete? Does it matter if the surface is damp?

To get Krytonite to adhere to concrete, you should first apply Krytonite Adhesive along the center of the construction joint. Then, press the Krytonite into the adhesive. When doing this, you should have enough adhesive on the surface that it comes out the sides of the pressed Krytonite.

This is the most optimal way of making sure that Krytonite stays firmly attached to the concrete surface.

That remains the case even if the concrete surface is damp as the adhesive can keep Krytonite up off the damp surface enough for the Krytonite to bond properly. That only works, however, if the surface is not too wet and is free from debris and pooling water.

Of course, if you’re set on using a different adhesive, the next best option is a one-component polyurethane construction adhesive.

Once applied, will it need protection?

Yes. It is possible for Krytonite to tolerate some early water exposure, but you should still take care to protect it from as much rain and moisture as possible before pouring concrete. Otherwise, the Krytonite could end up debonding.

To prevent that from happening, make sure the Krytonite is fully shielded from weather and moisture. A way to accomplish that might involve covering it with plastic to put a barrier between it and any possible water ingress.

Is there anything you’d recommend adding with Krytonite to waterproof construction joints and details?

While Krytonite will do an excellent job at protecting concrete construction joints and other small details, it works best with the KrystolWaterstop System. Under that system, you have Krytonite as well as Krystol Waterstop Treatment
, Krystol Waterstop Grout
, and Crack Inducing Waterstop.

When used in varying combinations, they can offer contractors a robust waterproof jointing system that’s available for low- and high-risk areas.

For low-risk areas, contractors can bring their concrete to a saturated surface-dry (SSD) condition and then coat it with the Krystol Waterstop Treatment. The Krystol technology in that treatment will react to water and unhydrated cement particles to form crystals that stop water from passing through. Then, the contractor can install the Krytonite to the concrete, further sealing the joint from water.

That acts as double protection for a structure that isn’t expecting to see a heavy amount of water ingress.

For higher risk areas, this system offers triple protection. That requires the same SSD condition and the same Krystol Waterstop Treatment and Krytonite application. But after that, contractors can apply Krystol Waterstop Grout to a keyway that’s formed with the help of the Crack Inducing Waterstop, adding extra Krystol technology protection.

All of that builds redundancy into the waterproofing system, giving it better protection from possible installation and material failures and from water ingress.

If I were interested in installing Krytonite and the rest of the Krystol Waterstop System, who should I go to?

We have territory managers and distributors all around the world who can help you. To find out who’s nearest to you, just send your request to Kryton on our contact us page or call Kryton’s headquarters anytime at 800-267-8280. There is always someone ready to help. And of course, if you happen to be in the eastern area of the USA, I am always happy to talk with you to see how Krytonite and the Krystol Waterstop System can best serve your concrete waterproofing needs.

Thanks again for chatting with us, Christian! We’re glad to see just how valuable Krytonite and the Krystol Waterstop System can be.

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4 Advantages of Polished Concrete Flooring

4 Advantages of Polished Concrete Flooring

Polished concrete flooring has gained popularity in recent years for its durability, low maintenance, and affordability. If you’re thinking about getting your floors redone but haven’t narrowed down your choice of material just yet, continue reading.

Polished concrete floors are perfect for both homes and businesses. They can be used in a variety of spaces, including kitchens and garages. Some of the biggest advantages of this type of flooring include:

1. Extreme durability

Concrete can last for decades without needing to be repaired or maintained. It doesn’t peel, scratch, or fade over time like most other types of flooring. This makes it a particularly great choice for cat or dog owners whose pets tend to scratch up the floors. Not to mention, it will save you money in the long run by reducing repair or replacement costs.

2. Requires very little maintenance

In addition to being extremely durable, polished concrete flooring is also easy to clean and maintain when compared with other types of flooring. Pet stains and spills come up easily and can be swiftly cleaned away without the need for special and expensive cleaners. This makes polished concrete a great choice if you’re looking for flooring that will stay beautiful without requiring time-consuming care and maintenance. 

3. Endless color options 

Contrary to popular belief, concrete doesn’t have to be gray and dreary. Polished concrete comes in an array of beautiful colors, including both classic and modern choices that will blend seamlessly with your existing décor, giving your home or business an entirely new look.

4.  Affordability

One of the biggest advantages of polished concrete floors is the low cost. This flooring is an excellent choice for homeowners and business owners who want to install new flooring but can’t afford pricey wood or marble. 

While there are many distinct advantages to polished concrete, the success or failure of your flooring project ultimately depends on picking the right contractor. Our professionals at Port Aggregates are highly skilled in creating beautiful, precise pours every time. Contact us today to request a quote for your next project!

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5 Reasons to Choose a Rip Rap Retaining Wall

5 Reasons to Choose a Rip Rap Retaining Wall

A retaining wall is necessary for any landscape project.

Without them, shorelines will quickly erode or flood, and gardens become overgrown with weeds.

The most popular type of retaining wall is the traditional concrete block style that has been around since the 1950s.

However, plenty of other options are available. One such option is a type of limestone called rip rap.

This bulky stone offers an array of benefits. When used as a retaining wall, it’s:

1. Aesthetically pleasing

A rip rap retaining wall is an attractive way to add some interest and excitement to your yard or city shoreline. The irregular shapes of the stones give it a more natural, rustic look that complements a variety of styles.

2. Eco-friendly

Because limestone can be obtained from quarries, it has less environmental impact than other materials like concrete and steel. It is also a sedimentary rock, which means that it’s formed over time from the weathering of other rocks.

The process of obtaining limestone does not involve chemical treatments or strong acids like some materials do. It helps to protect the environment and human health during and after its creation.

In addition, limestone is a natural sponge that absorbs water. This makes it an especially good choice for areas like the South that experience heavy rainfall and hurricanes.

3. Great for protection against the elements and erosion

Thanks to its irregular shape, rip rap can be useful in more urban areas to protect buildings from heavy rains and flooding. It also prevents soil at construction sites from getting washed away by rainfall or runoff water that carries mud and silt into nearby waterways.

4. Long-lasting

Rip rap is a long-lasting material that can remain in your landscape for many years. Since it’s made from limestone, you can also rely on this material for its strength and durability. Unlike certain materials like cinder blocks, rip rap will not break down over time.

In addition, the limestone itself has been around since prehistoric times and will likely be here until another type of rock comes along to replace it. This provides an excellent return on investment compared with materials like wood or plastic which need replacing every few decades.

5. Easy to maintain

One of the final benefits of rip rap is that it’s easy to maintain. Unlike traditional concrete block walls, you don’t need to replace these stones since they’re not attached together with mortar or cement.

Instead, each stone rests on top of the other and can be removed when necessary (if repairs are needed or if you want to create a new design).

In addition, the irregular shapes and sizes of rip rap makes it easy to find just what you need for your project, whether that’s one large piece or several smaller ones. This is unlike many other types of retaining wall stone which are sold in pre-cut pieces.

Port Aggregates offers three types of rip rap: 10lb rip rap (6-10”), 30lb rip rap, and 55lb rip rap. Whether your goal is to prevent erosion or simply create a garden, we’ve got just what you need. Our high-quality crushed limestone is available in numerous sizes to suit your special needs. Contact us today to request a quote

The post 5 Reasons to Choose a Rip Rap Retaining Wall appeared first on Port Aggregates.

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4 Reasons Why You Should Use Concrete in Your Next Project

4 Reasons Why You Should Use Concrete in Your Next Project

Around the world, concrete is one of the most commonly used materials in construction.

From concrete patios and walls, to intricate fountains and fireplaces, this versatile material is perfect for any project in your home or business.

In this blog post, we will discuss four reasons why concrete should be the building material you choose for your next project.

1. Strength and Resilience

The secret to concrete’s durability is all in the science. When cement is mixed with water, a chemical reaction called hydration occurs. This reaction bonds the two substances together rather than just holding them together. The resulting chemical bond prevents concrete from crumbling, breaking apart, or pitting.

Concrete’s strength and durability allow it to withstand even the most extreme conditions, such as underwater environments, deserts, and extremely cold climates. It’s one of the most fire-resistant materials, and doesn’t burn like wood or other organic fixtures.

Not only is concrete strong, but it also gets stronger as it ages–unlike other construction materials that erode over time. This process is called hardening, and it occurs as a result of the formation of calcium silicate hydrate as the cement continues to hydrate. The integrity of concrete can last for decades. On average, you can expect concrete to last three times longer than most building materials.

2. Low Maintenance

Once concrete is poured and set, the job is pretty much complete. Unlike other building materials, concrete requires little to no maintenance; there’s no need to worry about discoloration or laborious upkeep.

3. Versatility

Concrete can be applied in numerous ways — hand-applied, sprayed, pumped, poured, and more. When freshly mixed, it is malleable enough to be poured and molded into anything. Builders can even replicate the appearance of wood or bricks by stamping the concrete.

You’re really only limited by your own imagination when you pour concrete. From stamping designs to creating elaborate patterns, there are endless design possibilities, making it a first choice for many builders.

4. Affordability

One of the greatest benefits of concrete is its affordability. Because concrete can be poured into just about any shape or size, it does not require extra materials to maintain its form. As a result, the overall cost of your project will be significantly less than if you were trying to work with other building materials such as tile or stone.

On top of that, concrete’s low maintenance combined with its durability reduce the overall operating costs and insurance. Even after disasters, rebuilds are a lot less cost exhaustive than they are with other materials.

If you’re looking for a cost-effective, versatile, and long-term solution, concrete is the best material for the job, and our dedicated experts here at Port Aggregates have you covered. Contact us today to start your next concrete project!

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