Page 7 - Guide to Managing Trade Effluent - 2023

Total Daily Volume: The sewage treatment works has the capability to treat a maximum amount
of effluent. A limit on the total daily volume of effluent that may be discharged into the sewer Example of Trade Effluent Consent Conditions
is set to ensure that the sewage works has enough treatment capacity available to treat the
effluent which it receives.
• The temperature of the trade effluent shall not exceed 43 degrees C
Suspended Solids: Tight limits on the concentration of suspended solids which may be discharged • The pH of the trade effluent shall not be less than 6 nor greater than 10
into the sewer are set. These limits are designed to minimise the presence of large concentration • The total Suspended Solids in the trade effluent shall not exceed 600 mg/l
of suspended particles which may settle out within the sewer itself (rapidly settling solids) causing • The total Ammoniacal Nitrogen in the trade effluent shall not exceed 200 mg/l
blockages and to limit the concentration of solids which may arrive at the sewage treatment • The total Phosphorous in the trade effluent shall not exceed 25 mg/l expressed as
works (poorly settling solids), a proportion of these solids may not be amenable to biological
treatment and will therefore increase the volume of sludge which will be generated, increase the Phosphorous (P)
operating costs for the sewage treatment works. • The Chemical Oxygen Demand from acidified dichromate (C.O.D) of the trade
effluent shall not exceed 400 mg/l expressed as O
Sampling and Monitoring: As a means of demonstrating compliance with the conditions of the • The highest rate at which the trade effluent may be discharged shall not exceed 15
Trade Effluent Consent, the need to monitor the flow rate and daily volume and the analysis
of spot samples of the effluent to confirm its composition will be defined. Sampling may be litres per second (54 m3/hr)
undertaken by the operator with periodic independent sampling and monitoring by the sewage • The maximum volume of trade effluent to be discharged in any continuous period of
undertaker. This independent monitoring provides a means of determining the accuracy of the 24hrs shall not exceed 1296 cubic meters
information provided by the operator. In addition to confirming compliance with the discharge • The total Iron in the trade effluent shall not exceed 10 mg/l
conditions the information obtained will also be used to calculate the costs (financial charges) • The total Aluminium in the trade effluent shall not exceed 0.5 mg/l
associated with the discharge.
• The total Chromium in the trade effluent shall not exceed 0.01 mg/l
• The total Copper in the trade effluent shall not exceed 0.01 mg/l
• The total Lead in the trade effluent shall not exceed 0.01 mg/l
• The total Nickel in the trade effluent shall not exceed 0.01 mg/l
• The total Zinc in the trade effluent shall not exceed 0.1 mg/l
• The total Thiourea in the trade effluent shall not exceed 0.05 mg/l
• The total Monohydric Phenols in the trade effluent shall not exceed 0.1 mg/I expressed
as Phenol (C6H5OH)
• The total Sulphides in the trade effluent shall not exceed 0.01 mg per litre expressed as
S
• The total Arsenic in the trade effluent shall not exceed 0.01 mg/l expressed as As
• The total concentration of cyanide in the trade effluent, excluding ferrocyanide and
ferricyanide, shall not exceed 0.05 mg/l as CN
• The total Sulphates in the trade effluent shall not exceed 200 mg/l as SO4
• The amount of Soluble Methane in the trade effluent shall not exceed 0.14 mg/l as CH4
• The trade effluent shall not contain any substance or substances which either alone,
or in combination with any other matter in the sewer or at the sewage treatment
works which would give rise to obnoxious, poisonous or flammable gases, or create a
statutory nuisance or would be harmful to the sewer network, the treatment process or
the disposal of effluents or sludge generated at the works

A shaken sample is to be used except for COD, where the sample shall be the supernatant
after 1 hrs of settlement.

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