122C01R SWTP Minimum flow, quantity and requirements for Commissioning, start-up and performance test

Presentation Summary 1-General description 2-Creteria of minimum flow selection/low flow problems 3-Minimum flow required4-Commisioning/start-up and performance test5-Clear water quantity required for testing activity6-Water and sludge circulation diagram7-Sewage quantity and conditions required for testing8-Required work

General description

Criteria of minimum flow selection The minimum flow that shall be provided for the acceptable operation parameters of SWTP is depending to the following parameters: 1-Design Plant capacity/equipment design flow Operation philosophy/continuity of operation Flexibility of operation (Trains number, Number of equipments on duty…) Hydraulic calculation 2-Biological treatment Residence time Sludge age Required aeration Upper velocity (settlement in the clarifier)

Low flowrate problem generation Low flow rate in the sewage treatment plan can generate the following problems: Discontinuity of operation caused by difference between inlet (minimum) and outlet (pump) flow Instability of MLSS concentration which causes bulking/sludge quality variation (Sludge change to very light brown color) Extended aeration which generate poor settlement of the sludge in the clarifier Over aeration which generate deflocculation or pin floc occurrence (Generate solid carry over and increase effluent flow turbidity) High Sludge age or sludge retention time which generates decomposition / Sludge decay, mixed liquor very dark brown in color Septic Odor

Minimum flow required: ParameterUnit 10% of average flow 20% of average flow 30% of average flow Standard Value Total average flow (phase I)m 3 /d8333- Minimum daily flow ratem 3 /d Equivalent inhabitant number MLSS concentrationg/l3 (3) 3-6 Minimum Required air flow rate Nm 3 /h Excess sludge flow rateKg/d Sludge minimum flowDay59.6 (2) Hydraulic retention timeH135 (1) 67 (1) 45 (1) F/M loading kg BOD/(kg MLVSS*d) 0.02 (2) < 0.1 Volumetric load kg BOD/(m3*d) < 0.36 In general condition, the minimum flowrate is between 10% to 30% of total average flow rate of the plant High sludge age Solid-liquid separation problems Carryover of solids Inefficient biological treatment High effluent turbidity High Hydraulic retention time Extended aeration/Poor settlement Over aeration  Deflocculation Water recycling from lagoon

Commissioning/start-up and performance test In order to ensure the good operation of SWTP, the remaining activities which will be performance is devised in two items as per fluid service used: -Activity which can be performed using clear water -Activity which will be performed using sanitary water 1- Fluid used

Commissioning/start-up and performance test 2- Main Testing Activity CommissioningStart-upPerformance test  Functional & operation test of equipments  Instrument scalibration & loop test  Process parameters adjustments  C&E and control philosophy check  Hydraulic profile check  Run the plant in AUTO mode Efficiency of the plant -Screening and sand -Biological treatment -Filtration & desinfection -Sludge treatment Clear waterSewage

Clear water quantity required In order to perform commissioning and start-up activity, the minimum water quantity which shall be provided is related to: -SWTP Process concrete basin volume (especially activated sludge basin and cross clarifier) -Water volume required for firefighting ParametersUnitOne trainTwo trains Water volume required for firefightingm32405 Water volume in ASBm Water volume in clarifiersm Effluent sumpm3403 Sludge storage tankm3490 Total required clear waterm

Flow circulation 1- Water circulation

Flow circulation 2- Sludge circulation

Sewage quantity required 1- Calculation criteria The sanitary water testing quantity is calculated according to the following parameter: o Capacity of basin for filling - ASB - Clarifier - Effluent sump - Piping & accessories o Period of stability - Process parameters stability - Water quality Achievement o Duration of performance test o Additional sludge required o Minimum flowrate required

Sewage quantity required 2- Calculation Results ParametersUnitValueDays Minimum Daily flowratem3/d Water required for equipment filling Water volume in ASB (one equipments)m34700 Water volume in clarifier (one equipment)m31640 Effluent sumpm3403 Sludge storage tankm3490 Dead volume for lagoonm31000 Othe Equipments and pipingm31000 Total water quantity for equipment fillingm SWTP process parameters stability (05 days)m Water quantity during Performance test (15 days)m Minimum sewage quantitym Required sewage quantitym Addtionnal dry sludge in ASB (by-truck)kg14100-

Requirements to ensure Performance test using sewage 1-Required daily flowrate Minimum flowrate of 1667 m3/d Maximum pollution load as mentioned in the contract 2-Additional sludge Additional sludge of about kg Sludge should be taken from similar plant 3-Continuous source of sewage 1667 m3/d minimum required flowrate each day Sewage shall not exceed 3 days storage for the good operation of the plant

Trucking/collection of the sludge before treatment The daily flowrate shall be provide continuously, Trucking of sewage from Al Jubail and collection for a long duration will generate many problems: o Anaerobic degradation o Water quality variation o Septic conditions o Settlement in the lagoon o Lagoon area low than required sewage quantity o m3/d is an assumption and can be increased as per process conditions/water quality

Conclusion Remaining test will be performed by two steps:  All Commissioning and start-up activity using clear water (at minimum m3)  Performance test using sewage In order to ensure the operation of the plant using sewage the following conditions shall be provided:  Minimum daily flowrate shall be about 1660 m3/d for the good operation of the plant  Continuous & permenant source of wastewater shall be provided to allow the bacteria to growth and ensure aerobic degradation of organic matter  The sanitary water consumption during performance test ( m3) is an estimation and can be changed as per water quality provided and period of stability before performance test  In order to decrease the transit period, an additional sludge quantity (about kg) is to be provided from another similar sanitary water treatment plant