# The Urban Waste Water Treatment (Scotland) Regulations 1994, Paragraph 5

Extent: S

The points of discharge of urban waste water shall be chosen, as far as possible, so as to minimise the effects on receiving waters.
TABLE 1
REQUIREMENTS FOR DISCHARGES FROM URBAN WASTE WATER TREATMENT PLANTS SUBJECT TO REGULATION 5(1) AND (2)
The values for concentration or for the percentage of reduction shall apply.
Parameters
Concentration
Minimum percentage of reduction
Reference method of measurement
Analyses concerning discharges from lagooning shall be carried out on filtered samples; however, the concentration of total suspended solids in unfiltered water samples shall not exceed 150 mg/l.
Biochemical oxygen demand (BOD5 at 20°C) without nitrification
25 mg/1 O2
70-90
Homogenized, unfiltered, undecanted sample. Determination of dissolved oxygen before and after five-day incubation at 20°C ± 1°C, in complete darkness. Addition of a nitrification inhibitor.
Chemical oxygen demand (COD)
125 mg/1 O2
75
Homogenized, unfiltered, undecanted sample Potassium dichromate.
TABLE 2
REQUIREMENTS FOR DISCHARGES FROM URBAN WASTE WATER TREATMENT PLANTS TO SENSITIVE AREAS WHICH ARE SUBJECT TO EUTROPHICATION AS IDENTIFIED IN SUB-PARAGRAPH (a) OF PART I OF SCHEDULE 1
One or both parameters may be applied depending on the local situation.The values for concentration or for the percentage of reduction shall apply.
Parameters
Concentration
Minimum percentage of reduction
Reference method of measurement
(1)Reduction in relation to the load of the influent.
(2)Total nitrogen means: the sum of total Kjeldahl-nitrogen (organic N+NH3), nitrate (NO3)-nitrogen and nitrite (NO2)-nitrogen.
Total phosphorus
2 mg/1 P (10,000–100,000 p.e.) 1mg/1 P (more than 100,000 p.e.)
80
Molecular absorption spectrophotometry
Total nitrogen
15 mg/1 N (10,000–100,000 p.e.) 10 mg/1 N (more than 100,000 p.e.)
70-80
Molecular absorption spectrophotometry

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Source: https://www.legislation.gov.uk/uksi/1994/2842/schedule/3/part/I/paragraph/5 (the official version)
Page: https://openlegislation.uk/urban-waste-water-treatment-scotland-regulations-1994/schedule-3/part-I/paragraph-5
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.