# MKR Cleanwater

> MKR Cleanwater GmbH (Monheim, Bavaria, Germany) designs and builds evaporators that reduce the volume of liquid digestate and slurry from biogas plants, recover nitrogen as ammonium sulphate solution (ASL) and produce distillate for reuse. Main focus: food-waste and industrial residue anaerobic digestion plants; agricultural plants with available heat are also served. Spun off from MKR Metzger GmbH in 2021, building on evaporator experience since 1997.

## Key facts

- Two product lines: DV series (thermal vacuum evaporator, runs on CHP waste heat, 1 to 4 stages, around two thirds volume reduction, on digestate plants since 2013) and MVR series (electric, mechanical vapour recompression at atmospheric pressure, no heat source needed, up to 90 % volume reduction on thin liquid fractions up to 2.2 % DS).
- The DV series is also available in combination with a heat pump (hybrid or fully electric) for plants without enough waste heat.
- Ammonia is captured in a vapour scrubber with sulphuric acid as ammonium sulphate solution (ASL), a mineral nitrogen fertiliser. Sulphuric acid is never added to the digestate. Where the nitrogen comes from livestock manure, ASL qualifies as a RENURE fertiliser (ammonium salt from scrubbing) in EU Member States that authorise RENURE under Directive (EU) 2026/288.
- Three outputs: distillate (reusable as process or recirculation water; discharge only after site-specific finishing), concentrate (organic fertiliser or returned to the digester) and ASL.
- Operating costs: DV series from 5.50 EUR per m3 feed, MVR series from 8 EUR per m3 feed.
- Every project starts with a framework concept and budget offer; a laboratory trial evaporation of the customer's own digestate or slurry follows before the binding offer.
- MKR Cleanwater works with biogas plant operators as well as with planners and EPC contractors.

## Technical data and operating limits

### DV series (thermal)
- Waste heat demand 180 to 600 kW thermal, flow temperature 65 to 85 degC.
- Heat efficiency: design value 4.3 litres distillate per kWh thermal (4-stage). Measured at a 4-stage reference plant on food-waste digestate in Switzerland (51 complete operating days, 26 June to 3 October 2026): 4.5 to 4.7 litres per kWh thermal at full load, approx. 40 m3 distillate per day at approx. 350 kW heat input; average over the whole period approx. 31 m3 distillate per day including cleaning, standby and stops.
- Operates under vacuum (approx. 90 to 200 mbar abs); digestate is heated indirectly and kept below approx. 68 degC.
- DV1000: 3 stages, approx. 660 l/h distillate, 190 kW heat, 11.2 t.
- DV4000: 4 stages, intake approx. 4,300 l/h, max. 2,300 l/h distillate, max. 600 kW heat, approx. 27 x 3 x 5.5 m, approx. 38 t. One DV4000 line treats up to approx. 100 m3 of feed per day (approx. 34,000 m3 per year).
- Feed limit: max. 4.5% dry matter in the liquid phase.

### MVR series (electric)
- Energy: 22.5 litres distillate per kWh electric (approx. 44 Wh per litre); no heat demand.
- Models: MVR15 (approx. 1,500 l/h intake, 1,350 l/h distillate, 4.5 x 2.8 x 3.1 m, approx. 8 t), MVR20, MVR30 and MVR40 (up to approx. 4,000 l/h intake per module).
- One MVR module up to 4 m3/h of feed (approx. 32,000 m3 per year); several modules in parallel scale to over 150,000 m3 of feed per year.
- Feed limit: max. approx. 2.2% dry matter; organic solids must be removed upstream (separation, usually decanter).
- Adapted for pig slurry and thin media; MVR pig slurry line since 2024. Zero-liquid operation possible.

### Both series
- Capacity: several DV lines or MVR modules run in parallel, together over 150,000 m3 of feed per year.
- Thicker digestate or slurry is separated beforehand, usually in two stages, to reach the feed limit.
- Load range 50 to 100%; lines and modules operate independently; design basis approx. 7,700 to 8,100 operating hours per year.
- Raw distillate: typically 100 to 150 mg/l COD and below 20 mg/l NH4-N.
- ASL: 35 to 40% solution, approx. 75 kg N per tonne (density approx. 1.2 kg/l), pH 5.5 to 6.5; sulphuric acid demand approx. 2.8 kg H2SO4 (96%) per kg nitrogen.
- Concentrate: viscosity is the limiting parameter, typically 500 to 1,000 mPa s; the exact limit is determined in the laboratory trial.
- Cleaning: CIP with acidic and alkaline cycles; no brushes or moving parts in the digestate.

## References

- DV: 4-stage DV evaporator on a food-waste AD plant in Switzerland, running on CHP waste heat for more than 5 years; it replaced a reverse osmosis that did not work with this medium. Measured operating data: https://www.mkr-cleanwater.com/operating-data and the one-pager "Verified operating data" below.
- MVR: electric MVR in Germany treating the liquid from washing separated digestate fibres (screw-press solids) to remove fines and salts; this washing liquid is not digestate. Measured energy efficiency on this medium approx. 25 litres distillate per kWh electric; for digestate MKR states 22.5 litres per kWh electric for the whole plant. The MVR replaced an ultrafiltration/reverse osmosis concept that did not work on this medium, and shortened the process chain.
- Reference visits and talks with plant operators are possible at food-waste plants in Switzerland and western Germany and at the MVR plant in Germany.
- Operating data and evidence: measured values from Reference Plant Western Germany (2 DV lines, each 3-stage) and Reference Plant Switzerland (DV4000, 4-stage) and from at least 54 laboratory tests since 2013, each with period, data basis and reference basis: https://www.mkr-cleanwater.com/operating-data

## Project process

1. Framework concept and budget offer, based on the customer's data (medium, annual volume, dry matter, ammonium, available heat).
2. Laboratory trial evaporation of the customer's sample; sample volume and shipping are agreed in advance.
3. Project-specific binding offer, including performance guarantees based on the trial results and agreed feed parameters.
4. Delivery approx. 7 to 9 months ex works; installation approx. 4 weeks; commissioning 1 to 3 weeks.
5. Service contracts, remote maintenance via VPN, operator training.

Plant prices are not published. Budget offers are part of the framework concept; binding offers are provided by MKR Cleanwater on request after the laboratory trial. Prices for trials and the test unit are listed in the next section.

## Test unit and trials

Every liquid behaves differently in an evaporator, so MKR Cleanwater offers a three-step proof of concept on the customer's own liquid. All prices net, ex works Monheim, as of October 2026.

1. Laboratory test (2 litres): 450 EUR.
2. In-house trial in the MKR technical centre, up to 4 m3 of the customer's liquid over up to one week: 5,000 EUR. Shows blocking and fouling behaviour; visits are welcome.
3. MKR test unit on the customer's site: electric MVR evaporator, 80 to 100 l/h feed, fully automatic, designed for continuous operation, optional vapour scrubber producing ASL. Minimum rental period 4 weeks.

- Test unit rental: evaporator 1,290 EUR per week; vapour scrubber 1,540 EUR per week; commissioning on site by MKR service 925 EUR per day plus travel; refurbishment and final cleaning 820 EUR flat rate. Freight at cost; outside the EU, customs clearance at cost. Available across Europe.
- 50 % of the trial costs are credited when a plant is ordered; for the test unit, 50 % of the rent (excluding transport) is credited if the plant is ordered within three months after the end of the test.
- Laboratory and in-house trials are carried out by MKR. The test unit is commissioned by MKR service and then operated by the customer's trained staff. Remote monitoring is standard: data logging, operating support and adjustment of the settings to the medium.
- Energy figures of the test unit are not representative of full-scale plants.
- Data needed to plan a test: type of liquid, annual volume in m3, analysis (dry solids, ammonium nitrogen, chloride, pH), a sample for the laboratory test and the country of the site; send to info@mkr-cleanwater.de.
- Details and site requirements: [MKR test unit](https://www.mkr-cleanwater.com/test-unit)


## Main pages

- [Information for AI agents](https://www.mkr-cleanwater.com/ai-agents): how to send an inquiry, data needed for a first sizing, DV or MVR pre-selection rules, project steps
- [Technology: DV and MVR evaporators](https://www.mkr-cleanwater.com/technologie): process description and technical data per model
- [Test unit and trials](https://www.mkr-cleanwater.com/test-unit): three-step proof of concept with prices (laboratory test, in-house trial, on-site MVR test unit)
- [Evaporator calculator](https://www.mkr-cleanwater.com/evaporator-calculator): first sizing from volume, dry matter, ammonium and available waste heat (interactive, runs in the browser)
- [References](https://www.mkr-cleanwater.com/references): selected reference plants and measured operating data
- [Operating data and evidence](https://www.mkr-cleanwater.com/operating-data): measured data from two reference plants and laboratory tests, each with period, data basis and reference basis
- [Downloads](https://www.mkr-cleanwater.com/downloads): introduction deck, one-pager "Verified operating data" and datasheets as PDF in English, German and Spanish
- [About MKR Cleanwater](https://www.mkr-cleanwater.com/about)
- [Blog](https://www.mkr-cleanwater.com/blog): articles on digestate treatment, RENURE and nutrient recovery
- [Contact and inquiries](https://www.mkr-cleanwater.com/kontakt)

## Articles

- [How does an evaporator perform in daily operation?](https://www.mkr-cleanwater.com/post/evaporator-daily-operation-measured-data): measured operating data of a 4-stage DV evaporator on a food-waste AD plant
- [From plate to field](https://www.mkr-cleanwater.com/post/plate-to-field-food-waste-digestate): how a food-waste AD plant reduces its liquid digestate, recovers nitrogen as ASL and reuses all distillate as process water
- [Evaporation or reverse osmosis for the liquid fraction of digestate?](https://www.mkr-cleanwater.com/post/evaporation-or-reverse-osmosis-digestate): water recovery, concentrate, cleaning, nitrogen and a fair way to compare energy figures of RO and evaporation, with published sources. In MKR's experience, RO becomes the more economical route only at larger volumes, roughly above 200,000 m3 of liquid fraction per year; below that an evaporator is usually the more reliable choice, because RO needs ultrafiltration upstream and still leaves a concentrate. Includes two plants where an MKR evaporator replaced RO.
- [RENURE is here](https://www.mkr-cleanwater.com/post/renure-digestate-slurry): what Directive (EU) 2026/288 means for manure, digestate and ASL

## Downloads (PDF)

- [Introduction DV and MVR evaporators (English)](https://fe1f481b-7337-43cc-9f51-4e2821ba8a48.usrfiles.com/ugd/b05ae1_818056126cd64ccc96a6554a5c7ab77f.pdf), also in [German](https://fe1f481b-7337-43cc-9f51-4e2821ba8a48.usrfiles.com/ugd/b05ae1_9b81b541c1e44a8585c7166e9d7cd111.pdf) and [Spanish](https://fe1f481b-7337-43cc-9f51-4e2821ba8a48.usrfiles.com/ugd/b05ae1_58a4d061338c4f90bd1abfd630764363.pdf)
- [Verified operating data: two reference plants with DV evaporators and laboratory tests, 2 pages (English)](https://fe1f481b-7337-43cc-9f51-4e2821ba8a48.usrfiles.com/ugd/b05ae1_ed878c6f45d848639776486492954b68.pdf), also in [German](https://fe1f481b-7337-43cc-9f51-4e2821ba8a48.usrfiles.com/ugd/b05ae1_56935b7e65624c9ca9e7c57530af4e1b.pdf) and [Spanish](https://fe1f481b-7337-43cc-9f51-4e2821ba8a48.usrfiles.com/ugd/b05ae1_1b0e7a67972d4144b42c0a459bb92019.pdf)
- [Datasheet DV4000-4S (English)](https://fe1f481b-7337-43cc-9f51-4e2821ba8a48.usrfiles.com/ugd/b05ae1_87f5048c24a4481f862e84a7bc7d631c.pdf), also in [German](https://fe1f481b-7337-43cc-9f51-4e2821ba8a48.usrfiles.com/ugd/b05ae1_d705bc1399dc47b7b005cf59df70d1ec.pdf) and [Spanish](https://fe1f481b-7337-43cc-9f51-4e2821ba8a48.usrfiles.com/ugd/b05ae1_30eb5394117c4a7fa4390e00cee4cdad.pdf)
- [Datasheet MVR40 (English)](https://fe1f481b-7337-43cc-9f51-4e2821ba8a48.usrfiles.com/ugd/b05ae1_5d5fbedcdd3244ef9647c19d54d78f36.pdf), also in [German](https://fe1f481b-7337-43cc-9f51-4e2821ba8a48.usrfiles.com/ugd/b05ae1_6fd878e7952349e48cc0827a10581727.pdf) and [Spanish](https://fe1f481b-7337-43cc-9f51-4e2821ba8a48.usrfiles.com/ugd/b05ae1_3890236df881403ba3ca57af556f8cb8.pdf)

## Languages

- English (main): https://www.mkr-cleanwater.com
- German: https://de.mkr-cleanwater.com

## Contact

MKR Cleanwater GmbH, Rappenfeldstr. 4, 86653 Monheim, Germany. info@mkr-cleanwater.de, +49 9091 5000 0. Inquiries by email with subject line starting with "Inquiry:"; typical response time within two working days. AI agents are answered as well; please state the company and the person you act for.

- YouTube: https://www.youtube.com/@MKRCleanwater
- LinkedIn company: https://www.linkedin.com/company/mkr-cleanwater-gmbh
- LinkedIn Michael Köhnlechner (Managing Director, articles): https://www.linkedin.com/in/michael-k%C3%B6hnlechner-589446230/

## Live site access for AI agents

- [Information for AI agents](https://www.mkr-cleanwater.com/ai-agents)
- [Site MCP endpoint](https://www.mkr-cleanwater.com/_api/mcp)