Fairfax

Fairfax Fairfax Project Motivation and Objective Fairfax Water has contracted with CH2M HILL to investigate biofilms that are present in a channel downstream of the ozone contactors at the Griffith Water Treatment Plant (WTP). Among the important characteristics of biofilm are the amount and characteristics of the biofilms extracellular polymeric substances, or EPS. The Swette Center for Environmental Biotechnology (Biodesign Institute at Arizona State University (ASU)) has expertise in analyzing biofilm samples to characterize EPS. Therefore, CH2M HILL wishes to sub-contract the Swette Center at ASU to perform EPS analyses on biofilm samples from Fairfax Water. Research Methods Fairfax Water will ship to the Swette Center six biofilm samples that are clearly labeled as to source and other defining characteristics. Once the biofilm samples are taken, Fairfax Water will arrange for them to be put immediately on ice and shipped to the Swette Center for next-day delivery. This means that samples need to be taken on Monday through Thursday to allow deliver at the Biodesign Institutes loading dock, which operates only on weekdays. In addition, it is critical that the mailing address clearly indicate that they are to go to the Swette Center for Environmental Biotechnology. Shipments should be coordinated in advance with the Centers Laboratory Manager, Diane Hagner. The sample size needs to be at least 0.1 g dry weight. The recommended sample container is a 50-mL Falcon tubes. Packaging needs to protect the tubes from breakage during shipment, and they need to stay frozen until reaching the Swette Center. Samples will first be analyzed for Total Chemical Oxygen Demand (COD) using methods 5220D of Standard Methods (APHA, 1998), as implemented with HACH high-level kits. Then, the EPS will be extracted by the NaOH + formaldehyde method (Liu and Herbert, 1992), which generally gives the highest yield. Extracted EPS will be assayed for it contents of: carbohydrate using the phenol-sulfuric-acid method (Dubois et al., 1951), protein using the BCA method with the Pierce BCA Protein Assay Kit (Thermo Scientific 23227), and humics using the Folin method (Box, 1983). All EPS component values will be converted to COD. A typical biofilm mass density of 50,000 gCOD/m3 (Rittmann and McCarty, 2001) will then be used to make a rough estimate of the thickness of the total biofilm and the EPS. All methods and results will be summarized in a written report.