16:45 28 Mar 24
I-DEV0310: Deviation from Monitoring Plan, Tridecanter effluent.
Reference | I-DEV0310 | |
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Submitted by | DNV (22 Mar 2010) | |
Project activity | 1570: Granja Tres Arroyos Methane Avoidance in Slaughterhouse Effluents Project | |
Selected monitoring period | 25 Apr 2008 - 31 Aug 2008 | |
Title/subject of deviation | Deviation from Monitoring Plan, Tridecanter effluent. | |
Description |
There is a deviation from the revised monitoring plan (approved on 19/12/2009) regarding the measurements of the chemical oxygen demand (COD) of the wastewater at the exit of the tridecanter (CODww,tridecanter).
The revised monitoring plan states that the CODww,tridecanter will be determined every two working days. However, there is no CODww,tridecanter monitoring data available for the first verification period (25/04/2008 – 31/08/2008). The rationale for revising the monitoring plan originated from the re-configuration of the projects general arrangement. Specifically, there was a modification made to the returned wastewater from the tridecanter. Initially, this wastewater was to be discharged at the equalisation tank. However, in October 2008 it was observed that the returned wastewater from the tridecanter was discharged immediately downstream of the production plant exit. There was a fundamental technical reason for this re-configuration; by discharging the tridecanter wastewater immediately downstream of the production plant exit, the wastewater was mixed and thus its acidity diluted. This was also accompanied by a reduction in temperature. Combined, these design improvements would protect the integrity and performance of the dissolved air flotation system (a significant component in this wastewater treatment plant). This re-configuration, however, impacted the monitoring requirements and thus CODww,tridecanter would now need to be monitored. Given this re-configuration was not recognised until October 2008, there is a period of time where there is no monitored data, i.e. for the monitoring period in question (25/04/2008 - 31/08/2008) and part of the consecutive monitoring report which yet has to close. In the absence of data, the CODww,tridecanter has been conservatively estimated in order to calculate the chemical oxygen demand of the treated wastewater (CODww) according with the formula established in the revised monitoring plan: (Please refer to the equation in the attached document) In order to do that, measurements of CODww,tridecanter from 01/10/2008 until 31/12/2009 were analyzed (see below). |
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Assessment |
The proposed deviation from the monitoring plan is in accordance with the approved monitoring methodology applicable to the project activity according AMS-III.I version 4 considering the actual chemical oxygen demand of the wastewater.
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Impact |
In absence of CODww,tridecanter measurements prior to October 2008, CODww,tridecanter measurements from 01/10/2008 to 31/12/2009 were analyzed to determine a conservative value for the first monitoring period.
In accordance with the revised Monitoring Plan the CODww,y,m (tonnes/m3) is calculated as follows: (Please refer to the equation in the attached document) This equation is based on the diagrams available in Annex 4 of the revised Monitoring Plan. http://cdm.unfccc.int/UserManagement/FileStorage/GWUECXFA23QL67VT4J8DN9YH5OKISR Being Qww,total,y,m, CODww,total,y,m monitored, and Qww,tridecanter,y,m estimated during the first verification period. According with the registered PDD, the ERs are calculated as follows: (Please refer to equations in the attached document) Therefore, the higher the CODww,tridecanter,y,m the lower is the CODww,y,m and the ERs calculated. The CODww,tridecanter,m is calculated as the monthly average of the CODww,tridecanter monitored every two working days. For the period 01/10/2008 until 31/12/2009 fiftheen monthly averages were calculated based on monitored data available. Furthermore, the average and maximum of these monthly values were calculated for the refered period. However, in order to be conservative the highest CODww,tridecanter value directly monitored during the period 01/10/2008 until 31/12/2009 was selected to conservatively estimate the CODww,tridecanter,m for the first verification period. This value was compared with the average and maximum of the monthly values to demonstrate that conservativeness of this approach. The results included in the attached spreadsheet were: 1. La China facility: a. Average of monthly averages CODww,tridecanter,m value: 14,791 mg/l b. Maximum of monthly averages CODww,tridecanter,m value: 19,709 mg/l c. Maximum CODww,tridecanter monitored value: 27,136 mg/l i. Maximum CODww,tridecanter monitored value is 83% higher than the average of monthly averages value; ii. Maximum CODww,tridecanter monitored value is 38% higher than the maximum of monthly averages value. 2. Cahuané facility: a. Average of monthly averages CODww,tridecanter,m value: 11,580 mg/l b. Maximum of monthly averages CODww,tridecanter,m value: 15,567 mg/l c. Maximum CODww,tridecanter monitored value: 20,940 mg/l i. Maximum CODww,tridecanter monitored value is 81% higher than the average of monthly averages value; ii. Maximum CODww,tridecanter monitored value is 35% higher than the maximum of monthly averages value. Applying the above conservative estimate for CODww,tridecanter,m, the ERs calculated for the first monitoring period are 10% lower than the ERs that would be obtained applying the average of the monthly averages CODww,tridecanter,m. and 6% lower than the ERs that would be obtained applying the maximum of the monthly averages CODww,tridecanter,m.. Therefore, the present deviation is considered conservative and is likely to result in an underestimation of reported emissions reductions. |
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Annexes | Request for deviation with equations and figures (72 KB) | |
“GTA_Workbook250408-310808_v02” (196 KB) | ||
Link to the documentation made available at validation stage or monitoring report | Link to relevant documentation | |
Signed form | Signed form (410 KB) | |
Decision | This request for deviation has been accepted. | |
Current status | 20 May 2010 - Deviation accepted | |
Historic statuses |
22 Mar 2010 -
Submission received 16 Apr 2010 - Successfully passed the Completeness Check 04 May 2010 - Awaiting EB decision |
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