Nutrient R emoval from S laughterhouse W astewater in an I ntermittently A erated S equencing Ba tch R eactor
1. Laboratory-Scale Sequencing Batch Reactors (SBR) System
2. Slaughterhouse Wastewater
3. Operation of the System
4. Analytical Methods
Results and Discussions
1. Overall Performance of the SBR Reactor
2. Cycle Performance
Slaughterhouses produce high-strength wastewater.
The amount of wastewater generated per cow is approximately 2 m 3 per day .
In pig slaughterhouses, 1.6 – 8.3 m 3 of water per tonne .
S laughterhouse w astewater can be variable .
- S uspended S olids (SS)
- Chemical Oxygen Demand ( COD )
- Total Nitrogen ( TN )
- Total Phosphorus ( TP )
O n-site biological treatment by European Commission
- R emove O rganic C arbon (C)
- R emove N utrients
The European Commission also recommends that Sequencing Batch Reactors (SBRs) be amongst the Best Available Techniques (BATs) for Slaughterhouse wastewater treatment.
SBRs are capable o f:
- R emoving organic C
- R emoving nutrients
- R emoving SS
- H ave low capital
- Low operational costs
SBRs are not able to remove nitrogen (N) as efficiently as COD.
Anoxic heterotrophic denitrifiers reduce nitrate-N (NO 3 -N)/nitrite-N (NO 2 -N), which is produced in the preceding operational cycle and remains in the reactor after the draw phase, to nitrogen gas (N 2 )
P accumulating organisms (PAOs) will compete with denitrifiers for rbCOD for anaerobic P release.
A conventionally operated SBR can be changed to an intermittently aerated SBR, where one complete operational cycle comprises four phases – fill, react, settle and draw.
If the DO in the reactor tank is controlled properly by means of intermittent aeration, NH 4 -N will be partially oxidized to NO 2 -N and then in the mixing period, NO 2 -N will be reduced to N 2 gas.
the performance of a laboratory-scale, intermittently aerated SBR for simultaneous N and P removal from slaughterhouse water was investigated.
Laboratory- S cale Sequencing Batch Reactors (SBR) System
Slaughterhouse W astewater
Operation of the S ystem
Analytical M ethods
Method Laboratory- S cale Sequencing Batch Reactors (SBR) System
Collected from the conditioning tank in the wastewater treatment plant (WTP)
Reduce COD and N
Tertiary treatment (chemical coagulation)
The WTP comprises:
- Preliminary treatment (screening and dissolved air flotation)
COD, BOD5 and SS were measured in accordance with the standard APHA methods
TN i is the amount of N (mg) contained in the influent wastewater fed into the reactor tank during the fill phase
TN o is the amount of N (mg) contained in the effluent wastewater leaving the reactor tank during the draw phase
TN M is the amount of N (mg) utilized by microorganisms for biomass synthesis
(TND) i is the amount of N (mg)removed from the reactor tank by means of denitrification in the i th non-aeration stage (i = 1, 2, 3, 4)
Analytical M ethods
Results and D iscussions
Overall P erformance of the SBR R eactor
Cycle P erformance
Results and D iscussions Overall P erformance of the SBR R eactor
Results and D iscussions Cycle P erformance
At an influent OLR of 1.2 g COD/(L d), average effluent concentrations of COD, TN and TP were 150 mg/L, 15 mg/L and 0.8 mg/L, respectively. This represented COD, TN and TP removals of 96%, 96% and 99%, respectively.
A nitrogen balance was carried out and showed that 66% of N removed was due to denitrification and 34% was consumed by microorganisms for biomass synthesis.
Partial nitrification occurred in the system, possibly due to the intermittent aeration pattern employed in the SBR system. 95% of N removal by means of denitrification was via NO2-N.
Nutrient Removal from Slaughterhouse Wastewater in an Intermittently Aerated Sequencing Batch Reactor