What Is Wastewater?
Wastewater analysis determines the pollutant load of water at a treatment plant outlet or discharge point into a receiving environment. The parameter list is set by the facility's sector; organic load (COD, BOD), suspended solids, nutrients (nitrogen, phosphorus), oil-grease, heavy metals and sector-specific pollutants are measured.
Purpose of Wastewater
The purpose is to show the discharged water complies with the regulatory limit values and to monitor the treatment plant's efficiency.
Which Products Is Wastewater Applied To?
- Industrial facility discharge waters
- Domestic wastewater treatment plant outlets
- Organised industrial zone collector waters
- Pre-treatment outlet waters
- Cooling water discharges
In Which Sectors Is Wastewater Used?
Standards Related to Wastewater
- TS EN ISO 5667-1/-3 (sampling programme and preservation of samples)
- TS ISO 5667-10 (guidance on sampling of waste waters)
- TS EN ISO 15705 (COD — small-scale sealed-tube method)
- TS EN 1899-1/-2 (determination of BOD)
- TS EN 872 (suspended solids)
- TS EN ISO 17294-2 (determination of elements by ICP-MS)
Wastewater Conditions
- Specimen type
- Grab or composite; chosen per the discharge regime and directly affects the result
- Preservation
- Acidification, cooling or storage in the dark, depending on the parameter
- Time
- Each parameter has a maximum holding time defined in the standard
- Flow rate
- The discharge flow rate must be recorded for the pollutant load calculation
Equipment for Wastewater
- Automatic composite sampler
- COD thermoreactor and spectrophotometer
- BOD incubator and oxygen meter
- ICP-MS / ICP-OES
- Oven, muffle furnace and precision balance
Sample Requirements for Wastewater
- Sampling is the largest component of total uncertainty in environmental analysis. The specimen container, preservation (acidification, cooling, storage in the dark), fill method and time to reach the laboratory are all defined in the standard; if any one is not met, the result loses its validity. Sampling must be carried out by authorised personnel per a written plan.
- Separate specimens in different containers are required per the parameter list
- Sampling point, date, time and flow rate must be recorded
- If a composite specimen is taken, the sampling interval and duration must be stated
Duration of Wastewater
Parameters such as COD and suspended solids give quick results. BOD requires the incubation time the method demands and cannot be shortened; this sets the total reporting time.
Wastewater Procedure
- 1The sampling plan and parameter list are prepared.
- 2The specimen is taken in suitable containers with preservation.
- 3It is delivered to the laboratory via cold chain.
- 4The relevant standard method is applied for each parameter.
- 5Quality control specimens are run alongside.
- 6Results are compared against the regulatory limit values.
Wastewater Acceptance Criteria
The acceptance criterion is the discharge limit values defined in Water Pollution Control legislation according to the facility's sector; the discharge permit may also carry facility-specific limits. The applicable table and values are confirmed from the current legislation and the discharge permit.
Evaluation of Results
Grab and composite specimen results carry different meanings: a grab specimen shows the condition at that instant, a composite shows the average load. Which specimen type the legislation requires is decisive; a specimen taken with the wrong type is not used as the basis for compliance assessment.
Wastewater Report
- Sampling point, date, time and specimen type
- Discharge flow rate and, if any, production information
- Method, result and limit of quantification for each parameter
- Measurement uncertainties
- Regulatory limit values compared against
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- 2000/60/EC Water Framework Directive
- 91/271/EEC Urban Waste Water Treatment Directive
- (EU) 2010/75 Industrial Emissions Directive
Environmental Analysis — What Does This Testing Field Cover?
The section below describes the field that the Wastewater test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Environmental analysis determines the presence and concentration of pollutants in water, soil, waste, air and flue gas samples. The output of this family is usually part of a permit, a declaration or an inspection file; the result has direct legal consequences.
In this family SAMPLING is half the result, and this is the feature that most sets the field apart. A sample taken at the wrong time, in the wrong container, under the wrong preservation or from the wrong point gives an invalid result no matter how well it is analysed in the laboratory. In waste water a grab sample and a composite sample give different information; in soil, surface and depth produce different results. Sampling therefore has its own standards and its own accreditation scope.
On the water side, physico-chemical parameters (pH, conductivity, turbidity, COD, BOD, suspended solids), ions, heavy metals, organic pollutants and microbiological parameters are measured. Drinking water and waste water carry different parameter sets and different limits; the same laboratory method leads to a different decision under the two regimes.
In soil and waste, heavy metals, hydrocarbons, PAH and PCB compounds and LEACHING BEHAVIOUR are determined. The leaching test carries a logic peculiar to this field: it is not the total amount of a pollutant in soil but the fraction that can pass into water that determines the environmental risk. Waste classification and the disposal decision rest largely on this test.
On the emissions side, dust, sulphur dioxide, nitrogen oxides, carbon monoxide, oxygen, moisture and total organic carbon are monitored in flue gas. Measurement is made on site under operating conditions and must represent the plant's actual operating regime; a measurement taken at low load does not show the emissions at full capacity.
Continuous measurement systems are a separate body of work. In large plants emissions are monitored continuously and the accuracy of these systems is verified periodically by comparison with independent measurements; the quality assurance framework governs this.
Noise and vibration measurements complete the environmental impact side of the field: environmental noise mapping, workplace noise exposure and vibration exposure measurements produce evidence for both environmental and occupational health legislation.
Method groups in this field
Sampling
Separate sampling standards for water, waste water, soil, waste, flue gas and ambient air; grab, composite and continuous sampling techniques.
Water physico-chemical
pH, conductivity, turbidity, colour, suspended solids, COD, BOD, TOC, alkalinity, nitrogen and phosphorus species.
Elemental analysis
Determination of heavy metals and trace elements in water, soil and waste by ICP-OES and ICP-MS.
Organic pollutants
Volatile organic compounds, PAH, PCB and organochlorine pesticides by GC-MS; hydrocarbon oil index.
Flue gas
Measurement of dust, SO2, NOx, CO, O2, moisture and total gaseous organic carbon; quality assurance of automated measuring systems.
Leaching and waste characterisation
Leaching tests and waste classification parameters; the basis for the disposal decision.
Commonly confused in this field
- An analytical result cannot be used on its own without the sampling record; the time, point, conditions and chain of custody are part of the report.
- Total content and leachable amount give different information; in waste classification, leaching behaviour is what counts.
- Emission measurement must be made under representative operating conditions of the plant; a result taken at partial load is misleading.
- Drinking water and waste water limits are defined in different legislation; the same parameter carries a different threshold under the two regimes.
- A sample from a single point does not represent the whole area; assessment of a contaminated site requires a grid-based sampling plan.
Which decisions these results support
- Compliance with environmental permits and discharge limits
- Quality assurance of continuous emission measurement systems
- Contaminated site assessment and the remediation decision
- Waste classification and selection of the disposal method
- Workplace exposure measurements and occupational health obligations
Related Tests
Frequently Asked Questions About Wastewater
Is a grab specimen sufficient?
The legislation and discharge permit determine this. For facilities whose flow and pollutant load vary during the day, a composite specimen better represents the real situation; a grab specimen only shows the instant it was taken.
What is the difference between COD and BOD?
COD measures all chemically oxidisable matter, while BOD measures organic matter that can be broken down by micro-organisms. The ratio between them indicates the wastewater's suitability for biological treatment.