Strathmore WWTP
Case Study
The Strathmore WWTP was constructed to replace eight extended aeration lagoons. The plant was designed to process 4,000 m3/day (1 MGPD) Average Day Flow, 10,000 m3/day (2.6 MGPD) Peak Day Flow and the permit stipulated effluent of less than 20 mg/l BOD and TSS, less than 5/10 mg/l N-NH3 in summer/winter respectively, less than 1 mg/l Total Phosphorus and less than 200 MPN/100 ml fecal coliform. The plant features included headworks, two USBF bioreactors, alum storage and dosing and a UV disinfection system. Alum solution (49%) was dosed into the anoxic compartment of the bioreactors. Phosphorus precipitation and coagulation took place within the bioreactor internal circulation. Filtration was solely by the USBF clarifiers - the process did not include effluent post-filtration. The plant was operated in May 2002 by ECOfluid and turned over to the Owner’s operator in mid June 2002. Seven months of the plant operation and performance in 2002 are summarized in the following summary tables. The results confirm that loaded very close to its design capacity the plant performed well within the design parameters and better. All data are monthly averages of daily 24 hr composite samples. Daily duplicate 24 hour composite samples were sent to certified lab for analysis (Lab analysis available). Only the higher results were recorded.
INFLUENT DATA Flow BOD BOD TSS TSS TP TP NH3 NH3 2002 [m3/d] [mg/l] [kg/d] [mg/l] [kg/d] [mg/l] [kg/d] [mg/l] [kg/d] 3,818 213 813 208 794 4.1 15.7 14.4 55.0 179 669 189 707 4.1 15.3 14.5 54.2 3,431 226 775 218 748 4.7 16.1 16.0 54.9 3,335 229 764 221 737 5.0 16.7 19.8 66.0 3,237 255 825 252 816 5.2 16.8 19.9 64.4 3,091 266 822 304 940 5.5 17.0 20.3 62.7 2,969 269 799 251 745 5.6 16.6 24.5 72.7 4000 800 800 30 100 EFFLUENT DATA CBOD BOD TSS TP NH3 Total Fecal 2002 [mg/l] [mg/l] [mg/l] [mg/l] [mg/l] Coli Coli June 7 12 16 0.4 0.1 14 10 July 5 7 8 0.5 0.1 27 14 August 4 5 7 0.2 0.2 26 14 September 4 6 8 0.3 0.4 117 24 October 4 7 14 0.4 0.1 112 23 November 4 6 9 0.5 0.1 23 13 December 4 6 9 0.3 0.4 19 13 Average 5 7 10 0.4 0.2 48 16 Design 15 15 <1 <5/10 200
In terms of BOD and TSS the plant seven months average loading as 98% of the design capacity.
June
July
August
September
October
November
December
Average
Design
•Although not recorded daily, effluent Total Nitrogen when analyzed was <10 mg/l
•Spikes of high pH (11) were experienced by the plant in October
