Page 211 - AJWEP-22-6

Performance of Kalobe waste ponds, Mbeya

Table 5. Performance of facultative ponds:
Effluent characteristics and removal efficiency

Parameter Anaerobic Facultative % removal
outlet (mg/L) outlet (mg/L) efficiency
(this stage)
BOD 5 60.60 43.05 28.97
COD 284.32 102.27 64.02
TSS 128.78 56.67 55.99
Ammonia 9.68 4.91 49.28
(NH )
3
Nitrite 0.42 0.38 9.52
(NO )
2
TDS 963.00 920.40 4.42
Abbreviations: BOD : Biochemical oxygen demand, 5-day;
5
COD: Chemical oxygen demand; TDS: Total dissolved solids;
Figure 4. Anaerobic pond: Influent versus outlet TSS: Total suspended solids.
concentrations
Abbreviations: BOD : Biochemical oxygen demand, Table 6. Performance of maturation ponds: Final
5
5-day; COD: Chemical oxygen demand; TDS: Total effluent characteristics and removal efficiency
dissolved solids; TSS: Total suspended solids. Parameter Facultative Maturation % removal
outlet (mg/L) outlet (mg/L) efficiency
(this stage)
BOD 5 43.05 39.00 9.41
COD 102.27 78.00 23.71
TSS 56.67 41.00 27.61
Ammonia 4.91 3.00 38.90
(NH )
3
Nitrite 0.38 0.38 0.00
(NO )
2
TDS 920.40 892.00 3.09
Abbreviations: BOD : Biochemical oxygen demand, 5-day;
5
COD: Chemical oxygen demand; TDS: Total dissolved solids;
TSS: Total suspended solids.

system performed strongly in terms of COD, TSS,
and ammonia removal, while BOD reductions were
Figure 5. Facultative pond – parameter reduction moderate (Table 7 and Figure 7). Nitrite and TDS
Abbreviations: COD: Chemical oxygen demand; removal remained poor.
TDS: Total dissolved solids; TSS: Total suspended solids.
3.3. Seasonal and flow variation effects
this unit showed additional polishing of BOD, COD, Analysis of daily industrial discharge flow data for April
TSS, and ammonia (Table 6 and Figure 6). Nitrite 2025 revealed significant fluctuations in the volumes
remained unchanged, while TDS removal continued to received by Kalobe WSPs (Table 8). Peak inflows
be negligible. toward the end of the period coincided with temporary
declines in the performance of anaerobic and facultative
3.2. Overall treatment efficiency stages. During the highest recorded daily inflows, BOD
The cumulative treatment efficiency of the Kalobe WSP and TSS removals were approximately 10% lower than
system, from the anaerobic pond inlet to the maturation period averages, indicating that hydraulic shocks can
pond outlet, was calculated for each parameter. The depress treatment efficiency.

Volume 22 Issue 6 (2025) 205 doi: 10.36922/AJWEP025320249