31 August, 2020

Waste management

Waste management


At ProCycla we have extensive experience in the fields of management and treatment of organic waste, water and gases, offering integrated and modular solutions. Our close collaboration with major Technology Centers in the development of our technology solutions provides added value in innovation, efficiency and sustainability. The dissemination of publications and articles in different magazines of international prestige reflects and demonstrates the scientific, technical and innovative aspects in each of our solutions.

Organic waste is all waste that can be degraded in a biological way. Its origin, in plant and / or animal form, can come from urban, commercial or industrial activities. In particular, the agricultural sector (agriculture, livestock and forestry) generates a high amount of organic waste, making it essential to apply good management and treatments to avoid a negative environmental impact. At present, the biological processes most used for this type of organic waste in the agricultural sector are:


Biogas plants (Anaerobic Digestion)

Anaerobic digestion is a microbial fermentation in the absence of oxygen (O2) that gives rise to a mixture of gases, mainly methane (CH4) and carbon dioxide (CO2), known as ‘biogas’, and to an aqueous suspension or sludge that contains the microorganisms responsible for the degradation of organic matter, called ‘digestate’ or ‘digested’. The raw material preferably used to undergo this treatment is any residual biomass with high moisture content, such as food scraps, leaves and grass residues, livestock residues, sludge from urban wastewater treatment plants (WWTP) and other waste effluents. domestic and industrial. Biogas is used for the joint generation of electrical and thermal energy. Digestate is generally used as fertilizer, due to its better fertilizing properties, due to the mineralization generated in the process. At ProCycla we have different biotechnological solutions in the field of biogas:

It is a modular anaerobic digester designed by ProCycla, characterized by (1) having a ‘modified flow-plug‘ configuration: the reactor includes a stirring of the internal sludge; (2) innovative engineering and design: modular and scalable type, easy to build, with Hi-Tech; (3) automation and control: it integrates a biological control system that optimizes the anaerobic digestion process; (4) recovery of digestate as a fertilizer: residual digestate with a high content of nutrients. The solution allows you to reduce costs, increase your energy efficiency and treat a wide range of substrates, in a range of 2 to 15% total solids.

The circular structure in anaerobic digesters, or more commonly called the ‘complete mix‘ (MC) type, is the predominant option in Europe thanks to the enhancement that has been made of it in countries such as Germany or France, where it has been tending towards decentralization. Although there is no separation of the 4 phases of the biological process as occurs in the plug flow structure, it allows treating large-scale volumes, without requiring recirculation of the effluent. The solution, therefore, enables it to adapt to the necessary treatment volumes and offer a long service life for the assembly as it is a robust civil work.

The automation and control of biogas and anaerobic digestion plants are very important elements. Currently, the mathematical modeling of biochemical processes is of special interest for process analysis, control and optimization. The control tool developed by ProCycla optimizes anaerobic digestion and biogas generation processes through a modified ADM1 model applied to RFP and RMC reactors that integrates non-ideal mixing conditions and substrate accumulation, offering different advantages in the plant.

The cleaning of the biogas is essential to be used in engines and boilers. ProCycla has developed a drained bed biofilter that, with the help of bacterial cultures for the elimination of H2S, CO2, mercaptans and O2 present in polluting gases, present a more economical, practical and smaller solution compared to other conventional systems. The elimination of CO2 and H2S is between 95-100%. The combination of biogas generation treatment and biofiltration from bacterial cultures from biol (liquid fraction of digestates) results in the optimization of the overall process and minimization of costs.


Composting

Composting is an aerobic biological process, that is, in the presence of oxygen (O2). Under controlled ventilation, humidity and temperature conditions, it transforms degradable organic waste into a stable and sanitized product called compost, with good nutritional characteristics to be used as organic fertilizer. At ProCycla we carry out the transport and management of organic waste to transform it in our own facilities through composting solutions.


Nutrient recovery/removal

Livestock activity generates a high concentration of organic waste, mainly in the form of slurry, making the soils unable to absorb the large inputs of nutrients, especially nitrogen (N), causing productive damage and environmental problems, such as harmful seepage in subsoils, groundwater pollution, eutrophication and greenhouse gas (GHG) emissions. Nitrogen is a macronutrient, essential for plant life, so that its excess causes the proliferation of uncontrolled life. The surplus nitrates not used by plants is leached through the soil profile, since it is highly soluble in water. Nitrogen excesses above the needs of crops become a risk for water pollution. Waters affected by an excess of nitrates are no longer drinkable, since nitrates start to form nitro compounds. Nitrate contamination of surface and groundwater is one of the most serious public health and environmental problems today.

DAO is a partial nitritation. The oxidation of ammonium is carried out by autotrophic bacteria ANAMMOX (Anaerobic ammonium oxidation). It is a biological method that offers more advantages: (1) it is not necessary a carbon source; (2) biomass / sludge production is reduced; (3) the O2 demand is reduced by 60%. At ProCycla we wanted to go a step further and treat digestate directly in a single tank, without previously performing any type of solid-liquid separation. This implies reducing investment and operational costs, and improving the energy efficiency of the plant as a whole.


Microalgae

Currently, biological wastewater treatment systems have grown and increased in size due to increasing demand. This implies higher energy consumption and research into new technologies that are more compact, economical and respectful with the environment. Microalgae are photosynthetic microorganisms capable of generating organic biomass from inorganic sources of carbon (CO2) and light as an energy source. They require a contribution of water (H2O) to carry out the oxidation of organic matter, and therefore there is energy savings in aeration, in addition to greater efficiency in the recovery of nutrients. ProCycla works on the two main microalgae production systems: open systems (ponds, raceways, inclined pools, circular tanks) and closed systems (chambers, photobioreactors). Microalgae are presented as a promising alternative to other aerobic and anaerobic biological processes.


Vegetable covers

A vegetal roof is a type of inverted roof with the addition of an organic-mineral substrate, plants in its upper layer and a system of intermediate layers with different functions. At ProCycla we offer two types of plant covers: (1) extensive plant cover or ecological cover, which has a plant layer of a few centimeters (> 10cm), with low-size and maintenance plants (autochthonous), with a water supply and nutritional substances by natural processes; (2) the intensive vegetation cover or garden cover, has a thicker substrate (20cm), plants, shrubs, trees, irrigation installation and with a normal maintenance of a garden.

The extensive roofs are characterized by having upholstered vegetation of mostly native plants, typical of the region where the building is located. The plants must be resistant, since on the covers they can be subjected to strong winds, frost or excessive solar radiation, especially in the summer season. They must also be regenerable and be able to withstand periods of low irrigation due to natural rainfall or artificial irrigation (drip). Within the great family of succulents, moss and natural herbs, a multitude of native plants can be found in each region, suitable for forming a natural carpet that meets the conditions to be called “extensive cover”. Furthermore, the extensive roof is characterized by requiring a very low maintenance, which can be limited to two or three inspection and control visits per year.

The intensive garden-type covers include all existing plantations and crops, from grass to trees of maximum dimensions, combined with access for people, vehicles, ponds, lagoons, orchards, sports fields, wetlands for the treatment of gray water, and even swimming pools. It is carried out both on flat roofs and on underground garages. The construction of the slab has to correspond to the type of use of the roof and to admit the load represented by the vegetal layer and the destination and its traffic. It requires more maintenance and allows you to place a wide variety of plants. Even trees and ponds with ducks. The vegetation that supports are: grasses, herbaceous, shrubs and trees. The weight of this green roof can reach 500 kg / m2, so the structural resistance of the building must always be checked.