Safety first: and that applies to landfills, too
TeMa Geo Solutions’ thirty years of experience extends to the field of controlled landfills and contaminated sites, with products specially designed for each function to ensure the site is safe, and with investment-conscious solutions, as well as a focus on ensuring peak performance.
Safe landfills legislation
In Italy, regulation around the controlled disposal of waste dates back as far as 1982, later supplemented by the European directive and updated in 2020 by Italian legislation (D.Lgs no.121).
This legislation covers all aspects of the disposal cycle, from landfill classification to the type of waste, as well as criteria for the construction and operation of the facilities, with a strong environmental focus. In this regard, TeMa has come up with built-up systems and materials that fulfil the required functions and comply with the relevant legislation.
The main functions to make safe a controlled landfill
Making safe a landfill facility entails fulfilling a number of functions:
Barrier
Walls and floor must be isolated to protect groundwater and soil from leachate and biogases resulting from decomposition processes. To ensure sufficient watertightness, legislation requires the use of at least 0.5 m of clay or, drawing on the principle of hydraulic equivalence, synthetic products: sodium bentonite composites like Barrier Bento — which contains up to 5 kg of bentonite/sqm sandwiched between two geotextiles — provide an impermeable layer, acting as a barrier between soil and waste.
Reinforcement
One of the major issues to be addressed when designing landfills, especially the capping system, is stability, which can be achieved by leveraging the compressive strength of the soil combined with the tensile strength of geosynthetics. Reinforcement solutions provided by TeMa range from PET-series geogrids to geomats laminated with geogrids.
Drainage
For liquid and gas capture, legislation calls for the use of 50 cm of aggregate, which nonetheless can come with its own stability issues, especially on steeper slopes. With the use of drainage geocomposites, the relevant built-up system can be pared back, while the number of vehicles required to carry materials can also be reduced. TeMa’s offering ranges from studded and micro-studded membranes to monofilaments laminated with nonwovens, and geonets with one or two nonwoven layers.
Erosion control
The top layer of the soil is eroded by the action of the elements — especially by the type of unpredictable and extremely violent weather events we’ve witnessed in recent years — triggering alarming landslips, which can undermine a site’s hydrogeology. To prevent issues of this kind, it’s essential to encourage vegetation (which serves as a form of natural erosion control) and protect the soil while it takes root by using natural or synthetic mats from TeMa.
- Published in Drainage geocomposites and membranes, Erosion mats, GEO, Geogrids, Landfills, Landfills - Drainage, Landfills - Erosion control, Landfills - Reinforcement, Landfills - Waterproofing
Reinforced earth retaining walls: specific products for each function
The function of retaining wall structures is to retain and reinforce soil faces. They can be built in a multitude of areas, including private ones such as gardens and vineyards, as well as public areas such as roads, railways and embankments.
They meet the need to recover usable spaces as they can also be built with a steeply sloping face.
The authentic green appearance
Nowadays, the modern building industry is highly aware of sustainability and territorial integration. Under certain conditions, reinforced earth retaining walls can replace conventional concrete walls, without underestimating the aesthetic appearance of the landscape. This is even more important in areas subject to landscape restrictions that require the preservation of natural aspects using specific materials and construction techniques.
TeMa Building solutions integrate these trends by catering to various problems concerning land conformation and hydrogeological protection.
The functions of reinforced earth retaining walls and the products required to achieve them
Slope gradient, exposure to weather conditions (including severe ones) and the mechanical properties of the terrain often require technical solutions that stabilise a slope. Synthetic products can be used, each one performing a specific function.
Reinforcement with geogrids
The compressive strength of the soil is combined with the tensile strength of the geosynthetic product (such as T-Grid). The friction involved develops a tensional state that stabilises the structure.
Profiling with formwork units
Electro-welded metal structures such as formwork units provide a shaping of the soil face up to a 65° slope.
Controlling surface erosion with erosion control mats
Severe or prolonged weather conditions, such as strong winds and sudden downpours – and the resulting surface run-off of water – could lead to erosion and depletion at the face of reinforced earth layers, particularly if they are fully greened. The solution to this problem is to use, on the face of each layer, three-dimensional synthetic mats such as T-Mat made of polypropylene or K-Mat FG Green made of fibreglass. Alternatively, natural, biodegradable mats made of jute fibre such as T-Juta 500 can be used (also available in an XLversion).
Soil containment using gabions
An alternative solution to reinforced earth walls can be found in walls built using double-twisted wire mesh gabions, such as T-Gabion, filled with pebbles. Gabions are also an interesting solution for smaller residential projects: they provide containment while offering a different and innovative aesthetic appearance.
- Published in BUILDING, Retaining walls, Retaining walls elements
Reinforced earth structures as noise barriers
Hearing the noise of traffic outside your window all day long is irritating and distracting and, in the long term, also harmful to your health.
This is why the WHO and a number of laws govern the use of noise remediation systems in cities: the Framework Law no. 447 of 1995 for Italy and the European Directive on Environmental Noise no. 49/2022. If the cause of the noise cannot be addressed, the solution is to install protective barriers. Various kinds can be used, but in this case we focus on reinforced earth structures that require specific measures, which we discuss here.
For example, the Pedemontana Veneta is a new toll motorway in Italy: nearly 100 km long. Almost entirely in operation in the north-east of the Veneto region, the main route of this motorway runs through a deep trench in order to minimise the ‘territorial’ and environmental impact on the surrounding area. This means that long sloping areas of reinforced earth can be found along the sides of the motorway, with rows of trees and hedges for 58.61 km and green areas covering 1,333,410 square metres of hedgerows, groves, grassy slopes and tree-lined meadows.
A focus on noise with much regard for the landscape.
What do reinforced earth noise barriers consist of?
For this type of embankment with its typical trapezoidal shape, earth is used that will be covered by vegetation over time. Geosynthetic reinforcements and geogrids are added to support the earth, which already has good compressive strength. These are inserted horizontally into the ground and develop friction and tension that stabilise the structure, increasing its resistance to stress.
The TeMa Geo Solutions offer includes the X-Grid Pet PVC range of geogrids, with different resistance values, which are ideal for all kinds of contexts.
Another aspect to bear in mind is surface erosion of the soil: to counteract this, synthetic geomats are applied, also with a mulching function to encourage the growth of grass cover, or natural fibre bionets.
Also in this case, TeMa Geo Solutions offers a wide choice ranging from Ecovermat F Grass and Ecovernet FJ to the K-Mat range.
Why use a vegetation barrier as a protective noise barrier?
A vegetation barrier has an unquestionable ability to limit the spread of sound waves: some of them are absorbed, some reflected and some deflected. As a result, the amount of sound waves reaching the receiver is greatly reduced and noise can be dampened by several decibels.
The advantages of a reinforced earth sound-deadening barriera
Creating reinforced earth structures brings considerable advantages:
- it costs less because you can often use earth available on-site
- no special maintenance is required other than regular trimming.
- it helps the environment and integrates with it: the use of vegetation also reduces vehicle emissions by absorbing CO 2 and purifying the air.
Controlled landfills and the importance of isolating them
Landfills for inert, non-hazardous and hazardous waste are governed by specific laws in each country, which set out precise regulations on the construction and maintenance of these sites.
As they are virtually in the ground and designed for certain types of waste, they must meet environmental and safety standards.
Let’s take a look at everything in detail.
The risks of not isolating them
Assuming that proper disposal is essential, many types of waste can take years, even decades, to disintegrate and complete natural decomposition processes. At this stage, they produce a large amount of slurry, such as leachate, which is extremely contaminating for the soil and for groundwater.
Moreover, biogases are also produced, mainly methane and carbon dioxide, due to the breakdown of organic material, which must be controlled and could be used to produce renewable energy.
How to isolate them
Controlled landfills need to be isolated from the ground that hosts them, but to be safe they need to fulfil different functions.
Surface erosion control
Vegetation naturally protects the ground from erosion by weather conditions such as wind and rain, which would cause subsidence. While waiting for grassing to protect the sides and surface of the landfill, anti-erosion geomats, in a biodegradable and synthetic version, can be chosen according to needs.
TeMa Geo Solutions offers a wide range to choose from, which can be browsed here.
Reinforcement
A landfill site is sometimes designed and built on more or less steep slopes. If a slope is steep and the ground is unable to support itself, retaining grids need to be installed in order to prevent slippage, which would expose and damage lower layers. View all our solutions.
Drainage
Specific products, drainage geocomposites, can be used for the drainage of rainwater and leachate, which inevitably builds up and must be kept away from the ground.
Barrier
Bentonite-based products, such as Barrier Bento, allow the area to be waterproofed, including walls with high slopes and the bottom.
Capping
Landfills also have a final cover that must meet precise criteria. These include isolating waste from the ground and surface erosion control. However, minimising water seepage and blending into the landscape are equally important.
Cycle/pedestrian paths: when we get back onto our saddle, we’ll know more about them…
We know that our bike has become a mirage. But we can promise ourselves to use it more when this period of seclusion is over. Meanwhile, why don’t we take advantage of the time available to discover interesting things all around us? For example, cycle paths. Let’s start at the beginning.
What is the correct definition of a cycle/pedestrian path?
It’s where you can ride your bike, of course. But, can pedestrians walk on it too? What is the direction of movement? Then there are increasingly more complex questions, such as: has it been built as a separate cycle path or as a reserved lane? Is it a cycle/pedestrian path or a vehicular/cycle path? In short, there are many features that a cycle/pedestrian path must have in order to be defined as such. Let’s take a look at them together.
The cycle/pedestrian path was invented to allow pedestrians and bikes to get about. Such paths require cyclists to respect pedestrians and get off their bike whenever necessary to avoid getting in the way. Consequently, they are not paths for the exclusive use of cyclists.
Creating these kinds of paths encourages people to get about without using a car, thanks to these dedicated spaces, where they can feel safe from urban traffic.
How do you build a cycle/pedestrian path?
In 2018 TeMa Geo Solutions built a cycle/pedestrian path in Cozzuolo di Vittorio Veneto (TV). One of the main aims of the project was to improve road safety in an area that is a gateway to the city and where a city park is situated, used by families and children.
First of all, we enlarged the road and the nearby roundabout in order to create the necessary space for inserting the path. The enlargement was facilitated by the construction of a reinforced earth escarpment, for which reinforced geogrids were used. Installed in the ground, they create friction and enable the system to withstand significant levels of stress. The intervention work, designed on the basis of a single berm positioned at about 2 metres above ground level, allowed pedestrian and cycle traffic in an area that had been dangerous from the outset.
Looking on the bright side, when you get back onto your saddle, you’ll be more aware of what’s under your wheels. Enter the TeMa world, visit our website.
