1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)

OPtimal strategies to retAIN and re-use water and nutrients in small agricultural catchments across different soil-climatic regions in Europe (OPTAIN)

Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)

Approaches for design and realization of complex effective measures for tile drained agricultural catchments by land consolidations (QK21010341)

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)

Research Institute for Soil and Water Conservation (VUMOP) - Czech Republic

1.3 Conditions regarding the use of data documented through WOCAT

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:

Yes

1.4 Declaration on sustainability of the described Technology

Is the Technology described here problematic with regard to land degradation, so that it cannot be declared a sustainable land management technology?

No

Comments:

The advantage of the drainage biofilter is that it occupies only a relatively small area and only minimally impedes soil cultivation

1.5 Reference to Questionnaire(s) on SLM Approaches (documented using WOCAT)

2.1 Short description of the Technology

Definition of the Technology:

Biofilters or “bioreactors” connected to agricultural tile drains are relatively inexpensive and space-saving measures with considerable potential to improve the quality of drainage water.

2.2 Detailed description of the Technology

Description:

A biofilter or “bioreactor” is a relatively small installation used to break down pollutants from drainage water. Its basic function is to allow the passage of drainage water, contaminated with nutrients and pesticides, through a container with pollutant-reducing agents. Bioreactors are usually located at the bottom of agricultural drainage structures on the drains or in connection with drainage outlets. Ideally, the biofilter is located on a site that is no longer part of the cultivated land or is under permanent grassland.

In principle, two biofilter solutions are possible. In the case of low and regular drainage flows, the drainage section is directly replaced by a biofilter. With higher flows and in the case of rapid response of the drainage structure to rainfall-runoff episodes, the biofilter is placed parallel to the outlet drain or is located under the drainage outlet (if ambient conditions allow). Such a design includes a distribution structure (preferably located in a drainage manhole) and a drainage pipe to allow safe bypassing of a portion of the elevated drainage outlet, to maintain the residence time of the water in the biofilter and thus its corresponding efficiency.

The biofilter may be designed as closed or open. A closed biofilter is completely buried and normal tillage can take place. An open biofilter lacks the advantage of an undisturbed terrain but has the advantage of benefitting from plants that enhance the purification of drainage water by bacteria living on their roots.

The installation always consists of a bed or container in which the reducing agent is enclosed, ensuring the isolation of the agent from the surrounding soil and water. In the case of a smaller sized closed biofilter, a plastic container can be used, while in the case of a larger or open design, plastic film can be used as a bed. Various materials can be used as biofilter fillings, or substrates, both individually and in combination. In most cases, the reducing agent is carbonaceous, with denitrification mediated by chemo-organotrophic bacteria.

In terms of N-NO3 removal, the most effective are wood chips, which have a high hydraulic conductivity and a C:N ratio of 30:1 to 300:1. In particular, chips from poplar, pine and larch are suitable. For the removal of pesticides or biopharmaceuticals, then biochar (biochar) and lignite are suitable as natural and readily available materials. A combination of materials can also be used. For example, the addition of biochar to the wood chips will increase the efficiency of the bioreactor in degrading pesticides, or the charge can be combined with an inorganic substrate (sand, vermiculite), which is added to prevent undesirable settling, reduce hydraulic conductivity and at the same time mechanically purify the drainage water.

2.3 Photos of the Technology

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

2.6 Date of implementation

If precise year is not known, indicate approximate date:

• less than 10 years ago (recently)

2.7 Introduction of the Technology

Specify how the Technology was introduced:

• during experiments/ research
• through projects/ external interventions

Comments (type of project, etc.):

Several biofilters have already been implemented as part of research projects, and the development of a standardized, efficient and easy-to-implement solution is currently underway.

3.1 Main purpose(s) of the Technology

• protect a watershed/ downstream areas – in combination with other Technologies
• preserve/ improve biodiversity

• reduce diffusive agricultural pollution

3.2 Current land use type(s) where the Technology is applied

Land use mixed within the same land unit:

No

3.3 Has land use changed due to the implementation of the Technology?

Has land use changed due to the implementation of the Technology?

• Yes (Please fill out the questions below with regard to the land use before implementation of the Technology)

3.4 Water supply

Water supply for the land on which the Technology is applied:

• rainfed

3.5 SLM group to which the Technology belongs

• surface water management (spring, river, lakes, sea)
• ground water management

3.6 SLM measures comprising the Technology

3.7 Main types of land degradation addressed by the Technology

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:

• not applicable

Comments:

This measure is primarily aimed at improving water quality.

4.1 Technical drawing of the Technology

4.2 General information regarding the calculation of inputs and costs

Specify how costs and inputs were calculated:

• per Technology unit

other/ national currency (specify):

EUR

If relevant, indicate exchange rate from USD to local currency (e.g. 1 USD = 79.9 Brazilian Real): 1 USD =:

0.92

4.3 Establishment activities

	Activity	Timing (season)
1.	Selecting proper place for the measure	Before implementation
2.	Obtaining the consent of the owners and users of the affected land	Before implementation
3.	Project documentation	Before implementation
4.	Water management office permisiond and building permission	Before implementation
5.	Excavation works	Drier period, ideally at the end of the growing season
6.	Biofilter construction	Drier period, ideally at the end of the growing season
7.	Filling the biofilter with substrates	Drier period, ideally at the end of the growing season

4.4 Costs and inputs needed for establishment

	Specify input	Unit	Quantity	Costs per Unit	Total costs per input	% of costs borne by land users
Labour	Project/design	person-days	5.0	200.0	1000.0	100.0
Labour	Engineering	person-days	10.0	200.0	2000.0	100.0
Labour	Implementation of the measure	person-days	6.0	150.0	900.0	100.0
Equipment	Tansport of material	machine-days	5.0	150.0	750.0	100.0
Equipment	Excavation works	machine-days	3.0	220.0	660.0	100.0
Plant material	grasss seeding	kg	10.0	8.0	80.0	100.0
Construction material	Distribution object (manhole)	piece	2.0	2200.0	4400.0	100.0
Construction material	Container for filling the biofilter	piece	1.0	2400.0	2400.0	100.0
Construction material	Sorbents (vermukulit, biochar, woodchips)	m3	3.0	440.0	1320.0	100.0
Construction material	drainage pipes and other material	m	20.0	2.0	40.0	100.0
Total costs for establishment of the Technology					13550.0
Total costs for establishment of the Technology in USD					14728.26

If land user bore less than 100% of costs, indicate who covered the remaining costs:

co-financing from public sources

Comments:

Under certain conditions, owners and users of land, regardless of their legal form, municipalities and other public entities may apply for a subsidy for the implementation of this measure, which is provided by the Ministry of the Environment of the Czech Republic
The subsidy is up to 100 % of the total eligible expenditure, the minimum eligible direct implementation expenditure per project is set at CZK 250 000 ( 10 000 EUR), excluding VAT.

4.5 Maintenance/ recurrent activities

	Activity	Timing/ frequency
1.	Exchange of reducing agent in biofilter	every 5 - 10 years
2.	Cutting the grass aroun the measure	twice a year
3.	Checking and maintenance/repairs	once a year

4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)

	Specify input	Unit	Quantity	Costs per Unit	Total costs per input	% of costs borne by land users
Labour	grass chopper	machine days	1.0	100.0	100.0	100.0
Plant material	grasss seed	kg	10.0	8.0	80.0	100.0
Total costs for maintenance of the Technology					180.0
Total costs for maintenance of the Technology in USD					195.65

Comments:

It is necessary to replace the sorbent once every 5 years to once every 10 years. The price of sorbents (vermiculite, biochar, woodchips) EUR 1320 for ca 3 cubic meters needed. The price for transportation and switching of old and new sorbents is ca EUR 300.

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

The price of this measure is mostly influenced by its dimensioning for a certain water residence time of the drainage runoff (the above described example is dimensioned for a delay period of about 12 hours at a maximum drainage flow of 0.5 l/s). Another factor is the price of sorbents, where biochar and vermiculite in particular are quite expensive (approximately 250 EUR/m3). Alternatively, woodchips can be used (80 EUR/m3). The price can also be reduced by a simpler construction of the biofilter bed. The minimum price for this measure is estimated at EUR 3 200.

5.1 Climate

5.2 Topography

Indicate if the Technology is specifically applied in:

• convex situations

Comments and further specifications on topography:

The altitude varies between 549.8 and 497 m asl., The substrate is formed by partially
migmatized paragneiss in various degrees of degradation.
Quaternary sediments are represented by slope sands and
loams reaching 1–2 m thickness.

5.3 Soils

If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.

The representation of soils
(according to the World Reference Base for Soil Resources
2006) is variable, with Gleyed Cambisols, Gleysols, and
sporadically Histosols. In the recharge area, the soil cover is
more homogenous, with prevailing Modal, Ranker and
Arenic Cambisols.

5.4 Water availability and quality

Is water salinity a problem?

No

Is flooding of the area occurring?

No

Comments and further specifications on water quality and quantity:

Water quality is threatened by non-point source (agricultural) pollution, in particular by increased leaching of nitrate nitrogen and pesticides and their metabolites

5.5 Biodiversity

5.6 Characteristics of land users applying the Technology

5.7 Average area of land used by land users applying the Technology

5.8 Land ownership, land use rights, and water use rights

Land ownership:

• company
• communal/ village

Land use rights:

• leased
• individual

Water use rights:

• open access (unorganized)

Are land use rights based on a traditional legal system?

No

5.9 Access to services and infrastructure

6.1 On-site impacts the Technology has shown

Ecological impacts

Water cycle/ runoff

6.2 Off-site impacts the Technology has shown

6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)

Other climate-related consequences

Other climate-related consequences

	How does the Technology cope with it?
Irregular rainfall distribution and increasing number of runoff episodes	moderately

Comments:

A sudden increase in drainage flow during a rainfall-runoff episode may cause a short-term reduction in the effectiveness of the measures, whereby the residence time of water in the biofilter may be reduced and also a portion of the drainage runoff flows untreated through the bypass

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?

6.5 Adoption of the Technology

• single cases/ experimental

6.6 Adaptation

Has the Technology been modified recently to adapt to changing conditions?

Yes

other (specify):

treating of pesticide pollution

Specify adaptation of the Technology (design, material/ species, etc.):

The use of biochar and other advanced materials as substrates will enable the use of bioreactors to reduce water pollution from pesticides and their metabolites

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Relatively small and cheap measure
The measure does not require frequent and costly maintenance

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
High efficiency of drainage water treatment measures

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

Weaknesses/ disadvantages/ risks in the land user’s view	How can they be overcome?
Difficult to obtain subsidies for construction	Change in subsidy polices
Often different owner and user of the land concerned

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view	How can they be overcome?
Reduced efficiency during significant rainfall-runoff events	Correct sizing of the measure.

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

ZAJÍČEK, A., SYCHRA, L., VYBÍRAL, T., HEJDUK, T., ČMELÍK, M., FUČÍK, P., KAPLICKÁ, M. 2021: Design of the Revitalization measures on the Main drainage facilities and hydrologically related Detailed drainage facilities (In Czech)

Available from where? Costs?

https://doi.org/10.3390/w15061247

Title, author, year, ISBN:

Kvítek, T.; Zajíček, A.; Dostál, T.; Fučík, P.; Krása, J.; Bauer, M.; Jáchymová, B.; Kulhavý, Z.; Pavel, M. Slowing Down Quick Runoff—A New Approach for the Delineation and Assessment of Critical Points, Contributing Areas, and Proposals of Measures to Reduce Non-Point Water Pollution from Agricultural Land. Water 2023, 15, 1247.

Available from where? Costs?

https://doi.org/10.3390/w15061247

Title, author, year, ISBN:

Vrchovecká, S., Asatiani, N., Antoš, V., Wacławek, S., Hrabák, P. (2023): et al. Study of Adsorption Efficiency of Lignite, Biochar, and Polymeric Nanofibers for Veterinary Drugs in WWTP Effluent Water. Water Air Soil Pollut 234, 268.

Available from where? Costs?

https://doi.org/10.1007/s11270-023-06281-0

Title, author, year, ISBN:

Johnson, G. M.,Christianson, R. D., Cooke, R.A. C., Diaz-Garcia, C., Christianson, L. E. 2022. Denitrifying bioreactor woodchip sourcing guidance based on physical and hydraulic properties. ECOLOGICAL ENGINEERING, 184

Available from where? Costs?

DOI10.1016/j.ecoleng.2022.106791

Title, author, year, ISBN:

Christianson, LE et al., 2021. EFFECTIVENESS OF DENITRIFYING BIOREACTORS ON WATER POLLUTANT REDUCTION FROM AGRICULTURAL AREAS,AGRICULTURAL ENGINEERINGAGRICULTURAL ENGINEERING

Available from where? Costs?

DOI10.13031/trans.14011

7.3 Links to relevant online information

Title/ description:

Zajíček, A., Hejduk, T., Sychra, L., Vybíral, T., Fučík, P. (2022): How to Select a Location and a Design of Measures on Land Drainage – A Case Study from the Czech Republic. Journal of Ecological Engineering 2022, 23(4), 43–57. ISSN 2299–8993.

URL:

https://doi.org/10.12911/22998993/146270