Guidance

Monitoring discharges to water: alternative monitoring methods

Published 11 June 2020

Applies to England

General determinands

These are the monitoring methods for general wastewater quality indicators and inorganic parameters (excluding metals).

Ammonia

Method and comments Standard Reported LOD Reported range
Ammonia in Waters (1981). Several suitable methods presented. You can vary the limit of detection (LOD) and range by using a different instrument configuration. SCA blue book 48 0.5 mg/l 0 – 40 mg/l

Biochemical oxygen demand (BOD)

Method and comments Standard Reported LOD Reported range
5 Day Biochemical Oxygen Demand (BOD 5) Second Edition 1988 (with Amendments to Dissolved Oxygen in Waters) Procedure for 5 day incubation period, with addition of allylthiourea. SCA blue book 130 2 mg/l 0 to 6 mg/l Extended by dilution

Chemical disinfecting agents (including chlorine)

Method and comments Standard Reported LOD Reported range
Chemical disinfecting agents in waters and effluents (2008). Contains methods for all forms of chlorine, plus some procedures for determining other disinfecting agents used in water treatment. These include chlorine dioxide, ozone, bromine and iodine. If samples cannot be analysed immediately in a laboratory, you should use on-site methods. SCA blue book 218    

Chemical oxygen demand

Method and comments Standard Reported LOD Reported range
Determination of chemical oxygen demand (COD) in waters and effluents (2007). Contains 5 methods, 3 of which do not use mercury compounds. SCA blue book 215 10 mg/l 400mg/l, extendable by dilution

Chloride

Method and comments Standard Reported LOD Reported range
Chloride in Waters, Sewage and Effluents (1981) ISBN 0117516260. Several methods presented, not all are suitable for wastewater. You can vary the LOD and range by a different instrument configuration. SCA blue book 51 1 to 10 mg/l Up to 1,000 mg/l

Conductivity and pH

Method and comments Standard Reported LOD Reported range
The measurement of electrical conductivity and the laboratory determination of the pH value of natural, treated and waste waters (1978) ISBN 0117514284. SCA blue book 14    

Cyanide

Method and comments Standard Reported LOD Reported range
The determination of cyanide in waters and associated materials (2007). The methods presented are for easily liberated and complex cyanides, using colorimetry, potentiometry and continuous flow. SCA blue book 214 0.003 to 0.4 mg/l  
Water quality. Physical, chemical and biochemical methods. 3 methods for the determination of easily liberatable cyanide. BS 6068-2.18 0.02 mg/l 0.02 to 0.25 mg/l
Water quality. Physical, chemical and biochemical methods. 3 methods for determination of total cyanide. BS 6068-2.1   Up to 100mg/l

Nitrate, nitrite and total oxidised nitrogen (TON)

Method and comments Standard Reported LOD Reported range
Oxidised Nitrogen in Waters (1981) ISBN 0117515930. Covers several methods for both nitrite and TON, nitrate is calculated by difference. SCA blue book 40 TON 0.2 mg/l, nitrite 0.01mg/l TON 0 to 40 mg/l, nitrite 0 to 1 mg/l

Phosphorus and silicon

Method and comments Standard Reported LOD Reported range
Phosphorus and Silicon in Waters, Effluents and Sludges 1992) (ISBN 0117523771. A compendium of methods for both P and Si. SCA blue book 147    

Sulfate

Method and comments Standard Reported LOD Reported range
Suphate in Waters, Effluents and Solids 1988 (2nd Edition.) ISBN 0117522406. Contains 5 methods which are reported as suitable for wastewater. SCA blue book 136 0.1 to 5 mg/l up to 5,000 mg/l

Suspended solids

Method and comments Standard Reported LOD Reported range
Suspended, settleable and total dissolved solids in waters and effluents (1980) ISBN 011751957X. You should use a paper filtration method for suspended solids (Whatman GF/C paper or equivalent glass fibre paper with a nominal pore size of 1 to 1.2µm.) SCA blue book 105 2 mg/l  

Total and dissolved organic carbon (TOC and DOC)

Method and comments Standard Reported LOD Reported range
The instrumental determination of total organic carbon and related determinands (1995) ISBN 0117529796. Results will be influenced by instrument dependant considerations. 2 methods presented. SCA blue book 157 Instrument dependant, nominally 0.05 to 0.2 mg/l Instrument dependant

Turbidity

Method and comments Standard Reported LOD Reported range
Colour and Turbidity of Waters (1981) ISBN 0117519533. SCA blue book 103    

Metals

These are the monitoring methods for trace metals.

Arsenic

Method and comments Standard Reported LOD Reported range
Arsenic in potable waters by atomic absorption spectrophotometry, semi-automatic method (1982) ISBN 0117516791. No method performance data for waste water. SCA blue book 69   0.05 to 5 ug/l

Mercury

Method and comments Standard Reported LOD Reported range
Mercury in waters, effluents, and sludges by flameless atomic absorption spectrophotometry (1978) ISBN 0117513261. SCA blue book 10 0.1 to 0.2 mg/l 0 to 2 µg/l
Mercury in Waters, Effluent, Soils and Sediments etc [TA1] [HM2] (additional methods) 1985 ISBN 0117519073. Includes amalgamation and atomic fluorescence methods. SCA blue book 92 1 to 2 ng/l  

Silver

Method and comments Standard Reported LOD Reported range
Silver in waters, sewages and effluents by atomic absorption spectrophotometry (1982) ISBN 0117516783. SCA blue book 68 0.03 mg/l Up to 6mg/l

Trace metals (multi determinand methods)

Method and comments Standard Reported LOD Reported range
Inductively coupled plasma spectrometry (1996) ISBN 0117532444. Inductively coupled plasma atomic emission spectroscopy (ICPAES) and inductively coupled plasma mass spectrometry (ICPMS) are both covered. ICPMS may be the most appropriate method for very low concentrations. SCA blue book 163    

Organics

These are the monitoring methods for organic determinands.

Hydrocarbon oils

Method and comments Standard Reported LOD Reported range
Determination of hydrocarbon oils in waters by solvent extraction, infrared absorption and gravimetry (1983) ISBN 0117517283. Solvents recommended in the method are no longer in use – tetrachloroethene is now used. SCA blue book 77 0.2 mg/l  

Organotin compounds

Method and comments Standard Reported LOD Reported range
The determination of organic, inorganic, total and specific tin compounds in water, sediments and biota (1992) ISBN 0117523607. Performance data is not presented for effluents. SCA blue book 142    

Phenols and phenol index

Method and comments Standard Reported LOD Reported range
Phenols in waters and effluents by gas chromatography, 4-aminoantipyrine and 3-methyl-2-benzothiazolinehydrazone (1981) ISBN 0117516171. The gas chromatography method gives results for individual phenol compounds. The 4 colorimetric procedures are of the phenol index type. SCA blue book 50    

Steroid oestrogens

Method and comments Standard Reported LOD Reported range
The determination of steroid oestrogens in waters using chromatography and mass spectrometry (2008). Several methods are presented. SCA blue book 220 0.1 ng/l Up to 25 ng/l

Volatile organic compounds

Method and comments Standard Reported LOD Reported range
The determination of volatile organic compounds in waters and complex matrices by purge and trap or by headspace techniques (1998). Covers many volatile compounds including halogenated hydrocarbons. Applicable to (diluted) waste water. No performance data is presented for waste water. SCA blue book 170