Medeina FAQs
Here you can find the most
frequently asked questions about
Medeina
and their answers
OUR NATURE AGENTS:
WORMS & PLANTS
Depending on the type of sediment to be treated and its characteristics, Medeina uses (two) different types of local worms, mostly aquatic worms and earthworms. The distinctive attributes of aquatic worms make them particularly well-suited for fast dewatering in the presence of very fine sediments in a fluid medium. Meaning, these species are more suitable for deployment during the initial settling phase of fine particles in muddy slurries. As we progress in the treatment process, the introduction of earthworms – thanks to their ability to process larger portions of sediment into soil and their propensity for environments with lower humidity, complement the overall dewatering strategy. Their involvement contributes to enhanced efficiency in sediment volume reduction, facilitating the transition from ‘yogurt-like’ mud into healthy soils.
The lifespan of aquatic worms and earthworms can vary depending on various factors such as soil quality and chemical composition, moisture levels, temperature, predation and availability of food. While earthworms can live for several years under ideal conditions, aquatic worms typically have a shorter lifespan, averaging around 4 months.
As dewatering and compaction progresses within the sediment under treatment, conditions for worms become less advantageous as food and water availability decreases. Once the treated sediment has reached the desired moisture and settling levels, the worm population is expected to stop reproducing and thus to eventually disappear once their natural lifespan is reached.
Medeina eliminates the potential risk of introducing foreign worm species in landscapes at the very outset of each project. During the Scan and Design phases of our work process, we assess and select the most suitable worms within the available variety of endemic species, easily accessible at the location where a project or engineering intervention takes place. No invasive species will be used by Medeina, in fact not even non-local species will ever be considered.
Medeina uses endemic plants to dewater and strengthen sediment beds for engineering applications. Selecting the most suitable plants for a specific application depends on the type of sediment to be treated (e.g. marine vs. fresh-water). As plants offer an array of ecosystem and engineering services, the plant species to be deployed might be linked with the targeted engineering service. For instance, some plants are quicker in removing water, while others are better at developing a root network or strengthening the resulting soil.
Similarly as with worms, Medeina eliminates the potential risk of introducing foreign plant species into landscapes during the Scan and Design phases of our work process. Here, we assess and select the most suitable plants within the available variety of endemic species. That is, pioneering plants easily accessible at the location where a project or engineering intervention takes place.
PERFORMANCE OF NATURAL
AGENTS vs. TRADITIONAL ENGINEERING
Current sediment processing methods, including mechanical and chemical treatments, achieve greater performance (i.e. higher drainage) than alternatives. However, this performance comes at a much higher financial and environmental cost. Mainly because these more traditional methods use heavy machinery and specialized equipment that generate emissions and environmental pollution. While others consume large quantities of chemical additives to make the sediment flocculate (i.e. forming large clusters of sediment particles) and accelerate its dehydration.
Another popular sediment processing method is passive dewatering at ponds, commonly known as lagooning. Worms or plants constitute an important improvement in the efficiency for this type of dewatering operations (x20 times faster), without polluting or adding elevated costs.
Finally, Medeina’s tools are 100% locally sourced natural agents, endemic to the project’s context, which promote sediment circularity with zero emissions.
In this type of technical application, worms are never subjected to shocks intended to affect its population. As evidenced, worms used for engineering dewatering operations will stop reproducing progressively – as less favorable conditions for reproduction develop (e.g. with less water available). Whenever possible, we contemplate harvesting worm populations from already dewatered ponds and apply them to subsequent ponds where more favorable conditions will allow them to thrive once again and deliver their dewatering effect. It is worth mentioning that the latter consideration does not come from ethical concern, but rather from a cost-efficiency perspective.
There are clear rules with respect to the farming of worms, especially when they are to be introduced in the food chain (as animal feed or other agricultural applications). Moreover, legislation for using worms as composting agents is currently developing, and does contemplate limitations with respect to the type of feed that is permitted for farming. Though using worms as a dewatering agent does have a significant positive impact on the fertility of the treated soils, this technical application is nevertheless not considered as composting. We believe the organic load at the resulting (dewatered) soil is considerably smaller than in compost.
Still, in this evolving scenario, Medeina’s chooses practices that are 100% consistent with existing composting legislation with respect worm feed, i.e. no animal protein, no animal by-products, no biodegradable waste or GFT (Groente-, fruit- en tuinafval).
Medeina has studied the impact of different application methods of worms for dewatering purposes. To illustrate a comparison, our worms are like an engine that can be operated at different gears. We know our gears and have tested them extensively ahead to be able to give you the best possible service. So worms can be added to sediment ponds and beds in different ways, depending on project site conditions, equipment availability and total volume to be treated. For example, via injection pipes, as we know how much shear inside a pipe worms can withstand, even as a function of sand content.
Once added to the sediment on-site, worms colonize the entire sediment bed, seeking nutrition and oxygen. In this environment, worms typically consume the available organic materials such as dead plant matter, algae, bacteria and other organic debris. Typical organic matter contents, in dredged sediment and tailings, are in principle enough to keep the worms well fed while they are busy dewatering the sediment. The total time needed to dewater a dredged sediment slurry or tailing with worms is a function of the project characteristics. And as evidenced, it is an order of magnitude smaller given the feed availability in the soil.
APPLICATION REQUIREMENTS
Fine sediments may come from different sources, considering that slurry management is an integral activity in engineering operations across industries worldwide, including: construction, ports & navigation infrastructure, agriculture & food production, mining/oil/gas and wastewater treatment.
As a rule of tomb, sediment mixtures with a percentage of fine sediments of about 10 to 20% (silts and clays i.e. 0.05 to 0.002 mm, or smaller particle size) are more suitable for treatment with aquatic worms and pioneering plants. When the sand content of the sediment exceeds 50% to 60%, the treatment starts being less efficient. Nevertheless, we have also developed formulas to treat coarser sediment with larger sand contents via the application of terrestrial worms.
Medeina estimates the performance of our natural agents using two primary methods. The first method involves analyzing the granulometry, initial density, organic matter content, and salinity of a sediment sample. We then compare these measurements against our comprehensive database to predict performance outcomes. The second, more precise method, involves conducting tests in settling columns ranging from 1 to 5 meters in length. This allows us to extrapolate results to field conditions, maintaining as many consistent variables as possible to ensure accuracy.
Medeina’s solutions are designed to integrate seamlessly into your existing project site. Whether the application involves clay ripening, land reclamation, or sediment dewatering, the introduction of our natural agents—plants and worms—requires minimal additional tools or activities beyond standard engineering project procedures. To ensure the successful implementation of our solutions, Medeina requires a comprehensive understanding of the technical characteristics of the engineering intervention and its planning.
Medeina has tested our solutions across a variety of seasons and weather conditions, including rain, heavy rain, sunshine, heat, and mild weather. Our experience has given us deep insights into how these conditions influence worm behavior and plant development. With this knowledge, we are well-equipped to effectively plan, predict and integrate the performance of our solutions into your project, taking into account the local climate dynamics.
Medeina solutions, in particular worms, have been tested under different load conditions up to approximately 1 bar. Worms do not only survive the load, but also continue to provide enhanced dewatering under the load. This resilience allows for their application in capping operations, for example.
The impact of worms and plants on the geochemistry of contaminated sediments or soil is complex and varies based on local conditions. However, it is well-established that these natural agents profoundly influence soil microbiology, which in turn affects geochemistry through interactions with the newly established microbial community. Specifically, worms promote a healthy soil structure, while plants can accumulate heavy metals in their tissues, which is to be taken with care to prevent entry into the local food chain.
While neither worms nor plants directly remove contaminants, their ability to reduce sediment volume, enhance compaction, and accelerate dewatering supports other remediation strategies. In this way, Medeina’s natural agents play a crucial role in improving sediment management practices, contributing to the sustainable rehabilitation of contaminated sites.
WORM SOURCING FOR PROJECTS
Medeina Engineering exclusively uses self-grown worms, always. We have established partnerships with leading experts in worm farming, spanning both academia and the private sector, to ensure a sustainable and reliable breading of aquatic and earthworms for our projects. Our collaborations with hardware manufacturers for worm farms also enable us to produce up to hundreds of kilograms of worms. This gives us a clear competitive advantage and positions us as the best possible partner in worm sourcing with the required capabilities, space, organic substrates and time.
Medeina Engineering customizes worm breeding based on the desired dewatering speed and the scale of the project, which can vary project costs. We meticulously calculate the required quantity of worms and the optimal timing for their introduction. Depending on these factors, we design and set up a worm reproduction facility adjacent to the project site. The size of this facility can range from 10 m² to 100 m². For perspective, each square meter of our worm farms can produce between 1 to 5 kg of worms in just three months, depending on the availability and quality of feed. Thus, a 100 m² farm can yield up to 500 kg of worms within the same timeframe, ensuring we meet project demands efficiently and effectively.
USE CASES & FIELDS OF
APPLICATION
Medeina’s solutions significantly boost the efficiency of clay ripening. In traditional processes, the surface layer of clay dewater quickly, forming a dense cap that impedes further moisture loss from the underlying clay. The introduction of worms and plants improves the situation by increasing the permeability of this upper layer. Their burrowing and root systems create pathways that facilitate deeper and more rapid dewatering.
Additionally, the proportion of worms used to enhance dewatering is typically about 0.01% of the clay’s dry mass. These worms help to oxidize between 1% and 5% of the organic matter in the clay, leading to a net reduction in the clay bed’s organic content.
Furthermore, marine worms have shown promising results in the dewatering and ripening of marine clays. While Medeina does not currently farm marine worms, we can source them locally depending on the project’s needs and conduct a feasibility study to assess the economic viability of their use in specific projects.
Worms and plants offer valuable contributions to improving current practices used in land reclamation. Worms are instrumental in mixing various sediment layers, ensuring homogeneity and enhancing the uniformity of the reclaimed land. Their burrowing activities also stabilize the sediment, which helps in reducing erosion and preventing soil loss. Concurrently, plants play a crucial role; their roots absorb excess moisture, helping regulate soil moisture levels and preventing waterlogging. Moreover, the root systems help bind soil particles together, further reducing erosion risks caused by wind and water, thus synergistically enhancing soil stability in reclaimed areas.
Marine worms exhibit similar performance in marine dredged sediment as freshwater worms do in freshwater sediment, which has been extensively studied across various sediment types. Currently, Medeina does not yet farm marine worms; therefore, large-scale applications in marine sediments depend on the collection of these worms in the field. However, freshwater worms are capable of treating brackish sediments to a certain extent. Additionally, if the treatment of marine sediment includes a step where it is flushed with freshwater, then using freshwater worms could become a viable option.
Land reclamation is perhaps the most obvious application case of worms and plants. We are talking about adding endemic species to the freshly deposited sediment, species that will otherwise and in time colonize the area anyway. Our approach is to manage this colonization and to make it active so that the strengthening of the sediment matches your project requirements and characteristics.
IMPACT DELIVERED BY OUR SOLUTIONS
The use of endemic natural agents such as worms, plants, and algae in sediment treatment is inherently sustainable and environmentally friendly. These methods produce minimal to no emissions and do not introduce harmful chemicals into the environment. Furthermore, by promoting sediment circularity and enhancing soil quality, Medeina’s solutions contribute to ecosystem health and biodiversity preservation.
What are the potential economic benefits of using natural agents in sediment treatment?The use of natural agents in sediment treatment offers several potential economic benefits. By reducing the need for heavy machinery and chemical additives, Medeina’s solutions can significantly lower operational costs compared to traditional mechanical and chemical methods. Furthermore, the promotion of sediment circularity and the enhancement of soil quality can create opportunities for additional revenue streams, such as soil reuse and land reclamation projects.
The long-term benefits of using natural agents in sediment treatment extend beyond immediate dewatering and compaction. By promoting sediment circularity and enhancing soil quality, Medeina’s solutions contribute to the long-term sustainability of engineering interventions. This includes improved soil fertility, enhanced biodiversity, and reduced environmental impact, ultimately creating healthier and more resilient ecosystems for future generations.