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From page 62... ... 62 General considerations for deicer treatment system design and implementation are discussed in this chapter. 5.1 Sizing the Treatment System The basis of design for a treatment system provides information that is needed to complete the design and cost estimates for the selected deicer management system. Read the entire page →
From page 63... ... Designing and Implementing Deicer Treatment Systems 63 Mass Loading Rate. The mass loading rate refers to the mass of stormwater constituents conveyed, processed, or treated per unit of time, expressed typically in pounds per day (lbs/day) Read the entire page →
From page 64... ... 64 Guidance for Treatment of Airport Stormwater Containing Deicers concentrations of BOD, TOC, or COD and adjusting flow rates in response. Higher measured concentrations result in the need to reduce flow rates to maintain a constant loading rate and vice versa. Read the entire page →
From page 65... ... Designing and Implementing Deicer Treatment Systems 65 extremely rarely. The design capacities needed to manage worst-case conditions can be several times larger, for example, than the design treatment capacities needed to fully manage 90% of the deicing events. Read the entire page →
From page 66... ... 66 Guidance for Treatment of Airport Stormwater Containing Deicers 5.1.2.1 Effect of Temperature on Design Capacity The cold temperatures characteristic of deicer-affected stormwater may affect treatment in multiple ways: • Decreased levels of microbial activity reduce the mass of BOD that can be treated in a biological system per unit mass of bacteria. • Increased water viscosity reduces flow rates through membrane systems. Read the entire page →
From page 67... ... Designing and Implementing Deicer Treatment Systems 67 performance during the coldest months. During the coldest period for many northern airports, the water temperatures are frequently less than 41°F when the stormwater enters the treatment system. Read the entire page →
From page 68... ... 68 Guidance for Treatment of Airport Stormwater Containing Deicers – Providing external source of heat. � Heat exchange with hot water source fueled by: • Methane captured from anaerobic systems. Read the entire page →
From page 69... ... Designing and Implementing Deicer Treatment Systems 69 season. The inability to treat all water before the start of the deicing season could lead to several issues, including: • Degradation of the stormwater stored in the tanks, in particular over warm weather months. Read the entire page →
From page 70... ... 70 Guidance for Treatment of Airport Stormwater Containing Deicers where space is at a premium. The primary advantage to storage is that there is significantly less operational burden and cost to operate a storage structure compared to treatment. Read the entire page →
From page 71... ... Designing and Implementing Deicer Treatment Systems 71 5.1.2.5 Effects of Using Multiple Treatment Technologies on Design Mass Loading Rate Many airports use multiple treatment technologies within a single treatment system. Frequently, the collected runoff is segregated into fractions based on PG, BOD, COD, or TOC concentration. Read the entire page →
From page 72... ... 72 Guidance for Treatment of Airport Stormwater Containing Deicers 5.1.2.8 Use of Modular Systems to Split Required Design Capacity Many times, treatment systems are constructed as multiple smaller units rather than one large unit. Using multiple smaller units offers a number of advantages, including: • Ability to run the system in series or parallel mode, • Ability to have one or more treatment units offline for maintenance while continuing operations, • Operational costs managed by only operating enough units to meet the current treatment demand, • Better process control (e.g., more efficient mixing) Read the entire page →
From page 73... ... Designing and Implementing Deicer Treatment Systems 73 • Oversizing a treatment system can potentially result in: – Unnecessary capital and operating costs. – Compliance risk because of the difficultly in maintaining a continuous and stable treatment operation. Read the entire page →
From page 74... ... 74 Guidance for Treatment of Airport Stormwater Containing Deicers the dilution provided during the remainder of the time usually reduces average TDS concentrations in storage to avoid treatment impacts. However, the effect of TDS on deicer treatment systems has not been well-studied. Read the entire page →
From page 75... ... Designing and Implementing Deicer Treatment Systems 75 nutrient feed system includes mixing/storage tanks, metering pumps, and tubing to the injection point. Many of the existing biological deicer management systems have experienced instances of unintentional or accidental impacts from lack of nutrients. Read the entire page →
From page 76... ... 76 Guidance for Treatment of Airport Stormwater Containing Deicers 3. Programming loaded onto the PLC to provide the process logic and control mechanisms; and 4. Read the entire page →
From page 77... ... Designing and Implementing Deicer Treatment Systems 77 • When the construction is started (construction of some elements may not be feasible in winter) , • Weather delays during construction, • The degree to which components or unit processes come prepackaged, • The extent to which existing infrastructure is used, and • When funding is available. Read the entire page →
From page 78... ... 78 Guidance for Treatment of Airport Stormwater Containing Deicers • Troubleshooting; • Sampling, monitoring, and lab analysis; • Data entry, review, and analysis; • Performing maintenance; • Aligning treatment system operation with the rest of the deicer management system; and • Reporting to regulatory authorities. It is not always required or essential to have licensed wastewater treatment operators for deicer treatment facilities, but training of the operators in the specifics of the treatment system operation is essential. Read the entire page →

From page 62...

... 62 General considerations for deicer treatment system design and implementation are discussed in this chapter. 5.1 Sizing the Treatment System The basis of design for a treatment system provides information that is needed to complete the design and cost estimates for the selected deicer management system.