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Orenco Systems Inc. March 2002 AdvanTex AX10 Test Report minutes based on field experience from 3 and 4 bedroom homes. In comparison, previous research and testing carried out at the University of California in Davis, on a similar sized unit, used a ten minute dosing frequency. Consequently, a decision was made to increase the dosing frequency to determine if that would improve the filter performance further, and on June 4, 2001 (Day 233 in Week 34), the dosing frequency was increased to once every four minutes. The effluent CBODS concentrations continued to improve following this change (Figure 6) in spite of higher influent CBOD5 loading rates between Weeks 23 and 40 (over 50% higher loading than during the first 22 weeks), indicating that the increased dosing frequency further improved performance. The CBODS loading from Weeks 23 to 40 of testing was equivalent to a 4 to 5 person household. 4.5 Comparison With Davis Test Unit And NSF AX20 Results A similar size hanging-sheet filter unit was tested by H. Leverenz at the University of California, Davis for a period of 195 days. However, we understand that the Davis unit used a first generation textile material that had inferior treatment characteristics(i.e., water tended to flow across the surface at higher loading rates than desirable). The full Davis report is available in its entiretyfrom UC Davis, orfrom Orenco systems, and presently further testing is underway with the current generation of textile media. An AX20 unit (double the size of the AX10 unit)was tested by NSF at the Mamquam site in parallel with the AX10 unit but at a lower hydraulic loading rate than the AX10 unit. The full NSF report is available from NSF or from Orenco. The relationship between performance and hydraulic loading rates forthe three test units is — presented in Figure 14. It generally shows a gradual rise in both effluent CBOD5 and TSS concentrations with increasing hydraulic loading. The one anomaly is the generally "poorer" performance of the Davis unit at a loading of 36 gpd/ft2. This has been attributed by Orenco to the characteristics of that first generation media material which was very dense and resulted in a sheet flow down the surface at the higher hydraulic loading. Nova Tec Consultants Inc. Page 25 of 38