The Swedish Agency for Marine and Water Management's general advice on small sewage systems for domestic wastewater;

The Swedish Agency for Marine and Water Management’s general advice on small sewage systems for domestic wastewater;

Pursuant to Chapter 3. 5 § Miljötillsynsförordningen (2011:13), the Swedish Agency for Marine and Water Management issues the following general advice.
This general advice concerns the application of certain provisions in the Environmental Code and the Ordinance (1998:899) on environmentally hazardous activities and health protection (FMH) to wastewater facilities for the treatment of domestic wastewater from individual households
and from community facilities designed for up to 25 person equivalents (pe).

The following terms and abbreviations are used in this general advice:

Waste fractions: sewage sludge, toilet water, urine, feces and contents of closed tanks

‘sewage sludge’ means sludge from sewage treatment plants, septic tanks or similar installations treating domestic or urban waste water, or from other treatment plants treating waste water of similar composition

BDT water: bathing, dishwashing and washing water

BOD7 : biochemical oxygen demand measured over seven days.
Measurement of oxidizable substances (in the wastewater), see below under the section “Commentary on biochemical oxygen demand”, Appendix 2
BOD5 : biochemical oxygen demand measured over five days.
Measurement of oxidizable substances (in the wastewater), see below under the section “Commentary on biochemical oxygen demand”, Appendix 2

‘Stormwater’ means precipitation water, i.e. rainwater or meltwater, which
runs off superficially from yards, plots, streets, roads, roofed surfaces and the like

Drainage: dewatering of land by diverting sinking water
and groundwater in a pipeline or ditch FMH: Ordinance (1998:899) on environmentally hazardous activities and health protection

Domestic wastewater: wastewater from dwellings and service facilities, HVMFS 2016:17, which is predominantly toilet water or bathing, dishwashing and washing water (BDT water) MB: Environmental Code

Person equivalent (pe): pollutant load in terms of BOD7 and the specific pollutant load, 70 g BOD7
/ person and day, see below under the section “Commentary on biochemical oxygen demand”, Annex 2 Expert: person who, through professional experience, participation in training courses or by
other means, has sufficient knowledge to carry out the work referred to

Tot-P: total (both particulate and dissolved) phosphorus

Tot-N: total (both particulate and dissolved) nitrogen

Knowledge requirements:
Anyone who has installed or operates a wastewater facility should, by consulting the manufacturer’s instructions, hiring an expert or in some other way, acquire the knowledge necessary to maintain and operate the facility in such a way as to ensure its proper functioning.

Starting point for assessing wastewater facilities during inspection and
permit assessment The design load for a household should be based on an assumption of at least five pe and year-round residence unless there are strong reasons against this.

Level of protection
The local authority should, in each case, relate the health and environmental protection measures for the individual installation to a normal or high level of protection. The assessment of the level of protection needed should be made
on the basis of the natural and other conditions of the area in question. Municipal strategies and plans such as master plans or conservation plans for Natura 2000 areas can support this work. In addition, the conditions on the property should be taken into account.

The level of protection for health protection need not be the same
as for environmental protection.
If one or more of the following criteria are met, a high level of protection should apply to the protected interest.
1. The discharge from devices of the type in question may be expected to have a negative impact on the protected interest in an area which, pursuant to Chapter 3, Section 2 of the Ordinance (2004:660) on the Management of the Quality of the Aquatic Environment, is included in the register of protected areas.
2.Surface or groundwater sources for drinking water other than those referred to in 1 are located within the area of influence of the device and the device can be feared to contribute to nuisances with regard to the availability of water or the quality of the water in these sources, such as drinking water for animals.
3. MB entails a need for special precautionary measures.
4. Discharge of treated wastewater takes place directly, without prior delay in a ditch, for example, to sensitive surface water, e.g. near a bathing area.
5.The total load in the area is or is likely to be high due to the number of discharge sources; for example, in so-called conversion areas where recreational settlements have been converted into permanent dwellings and where this may lead to a gradual deterioration in water quality or quantity.
6. The receiving body or the surrounding area is sensitive for other reasons.

Safeguards, limitations and precautions
The permitting and regulatory authority should normally impose the following requirements when assessing wastewater facilities and handling of wastewater fractions on the property.

With regard to health protection, a balanced assessment should be made taking into account the robustness of the device, the reduction of pathogenic micro-organisms and the location of the discharge point. The requirements in the tables below are not designed as permit conditions, but indicate what should be achieved through requirements on the design of the device together with appropriate conditions on protective measures
and other precautionary measures.

Stricter reduction requirements or additional needs for
protective measures than those set out in these general guidelines may be justified on the basis of what is technically, economically and environmentally justified in the individual case.
Action programs drawn up in accordance with Chapter 6, Sections 5 and 6 of the Ordinance on the Management of the Quality of the Water Environment (2004:660) may form the basis of such an assessment. 5 and 6 of the Ordinance (2004:660) on the Management of the Quality of the Aquatic Environment may form the basis for such an assessment.

Basic requirements
Normal level
A. Storm water and drainage water are not led to the waste water system.
B. The waste water system, with the exception of any infiltration part, is sealed to prevent water from entering or escaping.
C. The operation of the wastewater facility is easy to check.
D. The wastewater facility is designed to facilitate maintenance and servicing.
E. The wastewater facility is constructed in such a way and at such a location that its operation can be maintained during the lifetime of the facility.
F. The wastewater facility is accompanied by an operating and maintenance instruction from the supplier containing the information needed to ensure the operation of the facility. Normally, the information set out in Annex 3 should be included.
G. The drainage device is, where necessary, equipped with an alarm in the event of operational or other malfunctions. An alarm should always be provided to warn before a closed waste water container has become full.
H. It is possible to take a sample of the waste water that comes out of the device in cases other than when the waste water is led to a closed container.

Health protection
Normal level
A. Discharge of wastewater does not contribute to a significantly increased risk of infection or other nuisance, e.g. odor where people may be exposed to it, for example through contamination of drinking water, groundwater or bathing water.
B. The handling of residues from the facility that takes place on the property can be managed in a hygienically acceptable manner.

High level (in addition to A – B)
C. Additional protective measures beyond the main treatment in the device are taken. For example, there may be a need to prohibit certain discharges, to make the discharge point more difficult to access, to increase the robustness of the device or to
add treatment steps that further reduce the pollutant content, increase the residence time, equalize fluctuating flows or receive any overflowed water.

Environmental protection
Normal level
A. Technologies that limit the use of water are used, e.g. water efficient fixtures.
B. Phosphate-free detergents and phosphate-free household chemicals are used.
C. The wastewater facility can be expected to achieve at least 90 % reduction* of organic matter (effluent content 30 mg/liter)
D. The wastewater facility can be expected to achieve at least 70% reduction* of total phosphorus-P (effluent concentration 3 mg/liter)
E. The wastewater facility enables the recovery of nutrients from wastewater fractions or other residues.
F. Measures are taken to minimize the risk of infection or other nuisance to animals.

High level (In addition to A – C, E and F)
G. The wastewater facility can be expected to achieve at least 90% reduction* of total P (effluent concentration 1 mg/liter)

H. The wastewater facility can be expected to achieve at least 50 % reduction* of total nitrogen (effluent content 40 mg/liter)
——-
* Can be converted to emissions per person per day or to
content mg/liter, see Annex 1.

Location
When assessing the notification of or application for a permit for the establishment or modification of a wastewater facility, the following should be taken into account:
1. Discharge of wastewater should be located so as to minimize the impact on the receiving water. Location that results in direct discharge to larger water bodies and that can be avoided by e.g. backwashing should not be allowed.
2. The outer edge of a sewerage facility (with the exception of any discharge pipe) should be located no closer than 10 m and preferably more than 30 m from surface water or ditch.
3. The outer edge of sludge separators should be located at least 10 m from residential buildings and at least 4 m from the property boundary. Sludge separators that meet the density requirements of SS-EN 12566-1, SS-EN 12566-4 or equivalent should have at least 20 m protective distance to the water source. Other sludge separators should be placed at the same horizontal protective distance as an unsealed device, cf. 10.
4. Sludge separators should be placed above the groundwater level.
5. Sludge separators should always be accessible to sludge removal vehicles.
6. Pipes that are leak-tested on site should have a protective distance of at least 10 m to the water source. Protective distances for non-tightness tested pipes should be at least 20 m.
7. Devices other than sludge separators and pipes, if they have passed tightness testing according to harmonized standards (as shown by the declaration of performance and CE marking) or have otherwise been tested for tightness with approved results, should be located at a minimum protective distance of 20 m from the drinking water source. If they are not leak tested, the horizontal protection distance from the sewerage system to the drinking water source should correspond to the groundwater transport distance for at least two to three months.

When wastewater is allowed to infiltrate into soil, the following should be taken into account:
8. Sewerage facilities should be located downstream in the groundwater flow from the water source. As a rule of thumb for this, the wastewater facility should be placed lower in the terrain than the well.
9. The groundwater level in the nearby water source should be higher than the level of the groundwater under the wastewater facility at maximum water extraction. If the water source is a rock drilled well, this criterion is not applicable as the level of the water source is governed by the ratio of inflow to and abstraction from the well. Instead, it should be ensured that the groundwater level in the soil layers adjacent to the well is higher.
10. Horizontal protection distance from the sewerage system to the drinking water source should correspond to the groundwater transport distance for at least two to three months at maximum water abstraction; however, the distance should never be less than 20 m.
11.The distance between the infiltration level and the highest groundwater level or rock should not be less than 1 m.
12. Sewerage facilities should be located downstream of the energy well.
13. Sewerage facilities should not impede the provision of water supply to other properties.

Recycling and management, management of residual products
The municipality should create the conditions for household waste consisting of sewage fractions to be utilized, for example by setting up systems for collection, treatment and storage and transfer to farmers, or by providing guidance on the use of the property in question while maintaining hygiene and
minimizing the potential spread of infection.

Considerations in the individual case
When assessing whether it is unreasonable to take precautionary measures under Chapter 2, Section 3 MB for a device, the following should be taken into account:
1. whether the wastewater device is already established in accordance with the permit and whether it functions as originally intended; for example, requirements for far-reaching phosphorus reduction may be unreasonably costly in relation to the environmental benefit that an upgrade of an otherwise well-functioning device would entail;
2. the amount and composition of the discharge in relation to the sensitivity of the surroundings;
3. if the location is in a very sparsely populated area, e.g. the northern Norrland hinterland or other part of the country with similar conditions;
4. when assessing requirements for nitrogen reduction: if the municipal
treatment plants in the area lack specific requirements for nitrogen reduction and the nitrate levels in the groundwater are low.

When assessing whether it is unreasonable to meet the functional requirements regarding recycling and management, the following should be taken into account:
1. whether the measures required by the requirements are technically demanding for the individual;
2. whether there are no conditions for long-term utilization
of the waste fractions.

Care, control and documentation
1. Sewerage equipment should be operated and maintained according to instructions where available.
2. A record should be drawn up by the supplier and kept up to date by the property owner. A note should be made when chemicals are added, samples are taken, major interventions are made, materials are changed or in the event of other measures of significance to the functioning of the device.
3. Operating and maintenance instructions, records and relationship drawings should, where appropriate, be kept on the property and be available for inspection by the supervisory authority.

The supervisory authority may, in the event of suspected malfunctioning or operational problems which may mean that the device does not meet the requirements, require sampling of the effluent from the device. Sampling should only
be required if the results of such sampling can be considered to provide information essential for assessing what further precautions need to be taken.

For the estimation of incoming concentrations, the default values in Annex 1 should be used.

Piping sewage from a separation toilet or similar to an existing BDT facility should be considered to require a permit.
Changing the location of an existing infiltration should be considered as a relocation that requires a new permit.

Assessment documentation for permit applications
When considering an application for a permit for a wastewater facility to which a water toilet is to be connected or a permit for another facility in a part of the municipality where the municipality has stipulated that such a facility is subject to a permit, the municipal committee should, to the extent necessary to assess the application, have access to the information specified in Appendix 4. The municipal
board should not request information from the applicant that it can obtain more easily from other sources.
The documentation should be based on the investigations carried out and be sufficiently detailed to enable it to assess whether the wastewater facility in the application meets the necessary requirements for the protection of human health and the environment.

Assessment basis for notification
When assessing a notification for the establishment of a wastewater facility to which a water toilet is not to be connected, at least the information specified in Appendix 4, points 1-2 and, depending on the choice of technology, point 4 should be included in the assessment basis.

Requirements in decisions
When granting a permit for the installation of a wastewater facility or when giving notification under Section 13 of the FMH, the municipal council should require that the work be carried out by an expert.
The municipal council should also require that the facility be inspected by an expert at least every ten years, or within such shorter period as the municipal council deems appropriate. Furthermore, the council should require that records of the inspection are kept on the property and can be presented at the request of the supervisory authority.
When deemed necessary, for example if the chosen technology is sensitive to disturbances or lack of maintenance, an annual inspection of the device should be required. In this case too, the municipal council should stipulate that records must be kept on the property and be available for inspection at the request of the supervisory authority.

Installation inspection
In the case of a permit or notification, it should be required that the device be installed in accordance with the application or notification or in another manner prescribed in the permit, and that the installation of specified critical parts be documented with photographs in accordance with an inspection plan laid down in the decision. The decision should stipulate that the documentation of this inspection and a certificate from
the installer that the device has been installed in accordance with the decision must be submitted to the municipal council.

What constitutes a substantial change should be assessed in relation to the load on the existing device. Both an increase and a decrease of the load can be considered as a substantial change.
Replacing a (deficient) septic tank with a new one at the same location should not be considered as a notifiable change.

Re-digging a soil bed or laying new infiltration pipes in an
infiltration plant should be considered as an action that may significantly change the composition of the waste water even if the purpose is to improve the plant.

Assessment basis for notification
When assessing a notification of a change to a licensable device, the same information as for a
license application should be included in the assessment basis. Details of the changes to the device to which the notification relates and the consequences this can be expected to have for the
quantity and composition of the wastewater should be included. To the extent that information is already known, it should be considered sufficient that only the additional information needed to assess the notified change is included.

Inspection in case of modification
If the modification is of such a nature that it significantly affects the functioning of the device, the municipality may, insofar as necessary, prescribe an installation inspection equivalent to that for a new installation.