The cheapest lawful way to reuse water in Spain
Every reclaimed-water system in Spain needs an authorisation, and that authorisation rests on a risk management plan. Keryon computes which combination of treatment stages and additional barriers reaches the required quality class at the lowest ten-year cost, then writes the plan that proves it.
- The engine searches every admissible configuration, instead of stopping at the first one that works.
- Each result carries the article and annex it rests on, so the file can be checked line by line.
- You receive the risk management plan, the permit file, and the monitoring evidence that keeps both valid.
For reuse system operators, irrigation communities and holders of reclaimed-water concessions.
Cost against compliance for one reuse system
IllustrativeThree rules decide whether a reuse scheme can legally operate
Real Decreto 1085/2024 replaced a fixed table of quality limits with a risk-based regime. That change moved the work from measuring water to designing and defending a configuration.
The plan comes before the permit
The risk management plan is a precondition of the production and supply authorisation, and the health authority's report on it is binding. Without an accepted plan there is no permit, and without a permit there is no lawful supply.
The intended use sets the target
The crop and the irrigation method fix the quality class, and the class fixes the pathogen reduction the scheme must achieve. Class A schemes must also be validated before they enter service, not after.
Barriers can sit outside the plant
An additional barrier may be provided by someone other than the plant operator and drawn from the Annex III catalogue. Drip irrigation, storage time or a crop restriction can replace capital equipment — which is exactly where cost is won or lost.
Compliance stated as an optimisation problem
A reuse scheme has more lawful configurations than anyone can price by hand. Keryon enumerates them, keeps the ones that satisfy the class, and returns the cheapest over the full permit term.
What can change
Treatment stages, additional barriers from Annex III, where each barrier sits along the chain, and who holds it — the plant, the irrigation community or the end user.
What cannot be broken
The quality class demanded by the crop, the irrigation method and the point of use, together with the monitoring and validation duties attached to that class.
What is minimised
Total cost of ownership across the ten-year authorisation: capital works, energy and reagents, sampling, and the staff time the monitoring regime consumes.
A computed configuration, end to end
Illustrative · Class A irrigationWhat arrives on your desk
Three products, sold separately or as one engagement, covering the permit from first application to the monitoring record that keeps it alive.
Risk management plan
The full PGRAR for the scheme: hazard identification, the computed barrier configuration, the monitoring regime, and the corrective actions attached to each control point. Written to be read by the health authority and the basin organisation.
Permit file support
The application package for the production and supply authorisation, with the technical annexes, the validation programme for Class A schemes, and answers to the queries that follow the first submission.
Monitoring subscription
The sampling calendar, the record structure the inspection expects, and a review of the configuration whenever the crop, the use or the rule set changes during the ten-year term.
A configuration that passes is not the same as the one that costs least
Two schemes on the same river, with the same crops, routinely end up with different equipment because each was designed by a different hand. The rules allow both. Only one is cheap.
The gap between the first feasible answer and the least-cost lawful answer is capital that the operator spends and then carries for ten years of energy, reagents and sampling.
Designed by hand
One configuration is proposed, checked against the class, and defended. Alternatives are never priced, because pricing them takes weeks.
Computed
Every admissible configuration is priced across the permit term. The cheapest lawful one is returned, with the rejected ones kept on record.
Agricultural users have until 31 December 2028
Permits are resolved in up to twelve months, and silence counts as refusal. Schemes that start late compete for the same reviewers as everyone else.
Candidates, prices, and the reason for the answer
The engine does not hide its working. Every configuration it rejected stays in the file, and every line of the decision points at the article behind it.
Candidate configurations
Ranked by total cost of ownership across the permit term
| Configuration | log10 | Capital | Annual | 10-year cost | Status |
|---|
Why this answer
Screen and figures are illustrative. Costs in a live run come from the scheme's own quotations and tariffs.
Build a barrier chain and see whether it holds
Secondary treatment starts the chain at 1.5 log10. Class A irrigation needs 5.0. Switch barriers on and watch both the reduction and the cost move — then ask the engine for the cheapest combination that passes.
Reduction values and the cost index are illustrative and shown on a common scale. A real assessment uses validated credits for the specific installation.
Secondary effluent alone does not reach Class A.
Four layers between the decree and the signed plan
Everything the inspection asks for, already written down
A permit is granted once and defended for ten years. The evidence layer keeps the configuration, the reasoning and the record in a form that survives a change of staff on either side of the counter.
Traceable decisions
Each control point in the plan is linked to the article, annex or validation result that justifies it, and to the alternatives that were priced and set aside.
Monitoring that matches the class
Sampling points, parameters and frequencies follow from the class the scheme claims, so the record answers the question an inspector actually asks.
Re-runs when things change
A new crop, a new user or an amended rule set re-opens the search. The scheme is re-priced against the current rulebook rather than the one in force when it was built.
The rules, the dates, and how many schemes they touch
Spain reuses more reclaimed water than any other member state, and since October 2024 every scheme has been operating under a risk-based regime with a fixed compliance horizon.
What the decree requires, article by article
| Provision | What it requires | What it means in practice |
|---|---|---|
| arts. 7.4, 21 | A risk management plan must accompany the application for the production and supply authorisation, and the health authority's report on it is binding. | The plan is the gate. Everything else in the file depends on it being accepted. |
| art. 8.3 | The competent body resolves within twelve months; where it does not, the silence is adverse. | A late or weak file is not simply delayed, it is refused by default. |
| art. 8.4 · Annex II.A | Class A schemes must complete a validation programme before the reclaimed water enters service. | Validation has to be planned and budgeted at design time, not after commissioning. |
| art. 10 | Authorisations run for a fixed ten-year term and may be renewed up to three times. | Every cost decision is a ten-year commitment, which is the horizon the engine prices. |
| art. 16.3 | An additional barrier may be provided by an agent other than the operator of the reclamation plant. | Cost can move off the plant balance sheet and onto the irrigation community or the end user. |
| art. 22.2.c · Annex III | Additional barriers are selected from the catalogue set out in Annex III. | The option set is finite and defined, which is what makes an exhaustive search possible. |
Summarised from the consolidated text published in the Boletín Oficial del Estado. The decree itself governs.
From the European regulation to the Spanish deadline
Select a milestone to read what it changed.
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How many schemes have to do this work
Spain reclaims an estimated 500 to 600 cubic hectometres per year. Every scheme behind that volume needs a plan and an authorisation under the new regime.
Reuse systems by river basin demarcation
EstimateMarket over a ten-year permit cycle
EstimateDerived from the estimated system count, the share in agricultural use, and the scope of work each authorisation requires across the ten-year term.
Where these figures come from.
Real Decreto 1085/2024, de 22 de octubre — regime for the reuse of reclaimed water. Boletín Oficial del Estado.
Real Decreto-ley 4/2023, de 11 de mayo — sets the 31 December 2028 adaptation deadline for agricultural users.
Regulation (EU) 2020/741 — minimum requirements for water reuse, applicable since 26 June 2023.
AEDyR — Spanish Desalination and Reuse Association, sector volume data. System counts, market values and the demarcation split are Keryon estimates built on published sector data, not official registers.
Built by people who have run the plants and signed the files
Keryon is based in Spain and works on Spanish reuse schemes. The team covers the four things a permit file needs: the method, the money, the measurement and the access to the operators who need it.
Four founders, four responsibilities
Nawal Cherikh
Sixteen years in water treatment operations across fifteen plants, twelve quality-control laboratories and roughly €95M of procurement. Owns the regulatory method and the plan itself.
Laguel Baya
Corporate banking at Crédit Agricole with agricultural portfolios covering about 150,000 hectares. Owns configuration economics: what a barrier really costs over ten years.
Yuri Vorona
Aviation engineer, then fifteen industrial steel projects delivered to EN 1090 with a zero-defect record. Owns measurement, validation and the evidence the file rests on.
Azibi Hillal
Eleven years building businesses, including rural solar development in Spain. Owns commercial access to operators, irrigation communities and basin bodies.
A permit file fails at whichever link is weakest
Each role owns one link, and each link has a clear failure mode if nobody owns it.
Method
The regulatory model, the plan structure, and the judgement about what a health authority will accept.
Without it: a technically sound scheme written in a form nobody can approve.
Economics
Cost models for every barrier, tariff and staffing assumption behind the ten-year comparison.
Without it: an optimiser that ranks options on numbers nobody trusts.
Evidence
Sampling design, validation programmes, and the record that holds up during an inspection.
Without it: a plan that is granted once and cannot be defended afterwards.
Access
Relationships with operators, irrigation communities and basin organisations, and the sales cycle around them.
Without it: a good product that never reaches the schemes that need it.
We would rather be checked than believed
Every claim in a plan points at the provision behind it. If a reviewer disagrees, they can find the exact line to disagree with.
A number without a source is not a number
Costs come from quotations and tariffs, reduction credits from validation, and system counts from published sector data with the uncertainty stated.
The cheapest lawful answer, not the most elegant one
An operator lives with the configuration for ten years. Elegance that costs money is a design failure, not a feature.
Talk to the person who owns the part you care about
Regulatory method, cost modelling, measurement or commercial terms — say which, and the right founder answers.
Tell us about your scheme
Send the basics — where the water comes from, what it irrigates, and where you are in the permit process. You get back a short written view of what the regime demands of you and what it is likely to cost.