## 4.21.2 Verification of treatment performance 

## 4.21.2.1  Treated Effluent Standards 

The required treated effluent quality to be fulfilled is stated in Volume 3: Employer's Requirements, Section 2.5.1 of the Employer's Requirements. The verification of this fulfillment shall be carried out during the Defects Notification Period following the Employer's Taking Over in accordance with the following procedures. 

All of the testing for compliance referred to below shall be carried out by an accredited laboratory which is to be approved by the Engineer. The composite samples shall be taken by means of sampling devices defined in Section 3.2.4. During the Defects Notification Period, the Engineer shall monitor the treated effluent for compliance with the stated effluent standards stated in the Volume 3: Employer's Requirements, Section 2.5.1 Table 2.4. 

Inlet 

A minimum of 48, flow-proportional 24-hour samples shall be collected at regular intervals for each year from the inlet to the treatment plant in order to assess the actual pollutant load. 

Outlet 

A minimum of 48, flow-proportional 24-hour samples shall be collected at regular intervals for each year from the effluent discharge main in order to monitor compliance with the requirements for treated wastewater. 

Compliance criteria 

The treated wastewater shall be assumed to comply with the relevant parameters if, for each of the relevant parameter considered individually, samples of the wastewater show that it complies with the relevant parametric value in the following way: 

 For the parameters of BOD$_{5}$, COD and TSS; the maximum number of samples which fail to conform is 3, 

 For the parameters of BOD$_{5}$, COD, and TSS, the failing samples taken under normal operating conditions shall not deviate from the parametric values by more than 100 percent. For the parameter of TSS, deviations of up to 150 percent shall be accepted, 

 For the parameter of TN and TP, the annual mean of the samples for each parameter shall conform to the relevant parametric values, 

 Extreme values for the wastewater quality shall not be taken into consideration when they are the results of unusual situations such as heavy rain. 

## 4.21.2.2 Dewatered and Dried Sludge Quality Requirement 

The required dry solids content of the dewatered sludge and dried sludge to be fulfilled is stated in Section 2.5.2 of the Employer's Requirements. The verification of this fulfillment shall be carried out during the Defects Notification Period following the Employer's Taking Over in accordance with the following procedures. 

All of the testing for compliance referred to below shall be carried out by an accredited laboratory which is to be approved by the Engineer. 

Procedure 

