Ahidra, agua y energía, S.L., in cooperation with four research centres of reference in Europe and 6 national and international companies, participates on the development of a manure treatment system for the recovery and reuse of the nutrients. The main novelty of this Project is based on the combination of new technologies that allow nutrient’s splitting from manure for its use within natural fertilizers.
Nowadays the mainly used fertilizers are synthetic, coming from fossil combustibles. The extensive use of this kind of fertilizers has caused the grounds for crops to be exhaust, mainly due to exhaustion of organic carbon, thus the capacity of provided nutrient’s retention is reduced. Basically, the fertilizers provide N, K and P: elements that are present in high amounts in manure, that at this moment are considered waste because of its direct relation within eutrofization phenomena.
At present date, no existing process for manure treatment is able to split its nutrients from the waste. The treatment for manure, because of environmental requirements, is focused to nitrogen removal, being the most common the nitrification-denitrification process. This process has high energy costs, impossibility for removed nitrogen’s recovery from water and important emissions of N2O gas which increases greenhouse effect (the N2O has a greenhouse effect 200 times higher than CO2). On the other side no nutrients recovery systems exists, neither able technologies for phosphorous and potassium selective recovery from manure.
The technical objectives of ManureEcoMine Project are focused on the study, design and development of a new manure treatment system that comprises:
Nitrogen removal: by partial nitrification/anammox implementation: different scientific studies have reported the viability of using partial nitrification/anammox treatment for digestate from manure. Nevertheless, no validation or implementation of the process exists nowadays.
Manure thermophilic digestion: one of the goals is the improvement of the state of the art related to thermophilic processes by coupling a stripping system to the digester in order to reduce ammonia levels.
The synergy between both processes will become into a more stable process that will allow:
o Increase on biogas production speed
o Nutrient release
o Improve on hygienization of the obtained digestate
o Reduction of digestate volume
o Nitrogen recovery in form of ammonia by the use of a stripper
o Nutrient recovery in splitted form, for which no state of the art exists
o Nitrogen recovery: it is expected that the combination of ammonia stripping with thermophilic anaerobia digestion process gives, as a result, the nitrogen recovery in form of ammonia sulphate
o Phosphorous and potassium recovery: nowadays no technologies are able to recover selectively these elements, thus the recovery by struvite precipitation will be carried into study.
– In presence of ammonia it is expected to obtain ammonia struvite, with a 13% of P.
– If the ammonia has been previously removed, potassium struvite will be formed, with a content of 12% of K.
By using a thermophilic anaerobic digestion process, the liberation of P on manure liquid fraction in form of phosphate increases and thus, a better recovery of it is allowed.
Considering that the levels of liberated P in thermophilic conditions are 2-3 times higher than the observed on mesophilic conditions, and being reported the potential of struvite precipitation on different pilot studies, at present project the combination of both technologies for the P recovery will be analyzed, for which no previous experiences exist.
Finally, the process outcomes can be discharged directly to the river, according to present regulations.
For the execution of the project, multidisciplinary working equipment has been constituted between the different companies of the consortium that will work together on the different duties described on the project’s memory. The next duties, where Ahidra, agua y energia, S.L. acts as project leader, are remarked:
· Development of a pilot prototype, start-up and tests
· Process optimization focused on interaction’s study between different stages.
· Operation tests under steady stable conditions. Evaluation of performance, and control and establishment of the optimal operation scheme.
· Study of the economic and environmental performance of the different alternatives developed.
The involvement of Ahidra, agua y energía, S.L is fundamental because provides its experience in advanced technologies on organic waste recovery and waste water treatment for the design of the new treatment prototype, as well as the validation of the new process and the evaluation of its economic and environmental performance.