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Practical Design Calculations for Groundwater and Soil Remediation - Chapter 5

Vadose vùng đất khắc phục hậu quả Chương này minh họa tính toán thiết kế quan trọng đối với thường được sử dụng trong kỹ thuật khắc phục hậu quả tại chỗ và đất trên mặt đất. Việc điều trị các quy trình được bảo hiểm bao gồm khai thác đất hơi, xử lý sinh học đất, rửa đất, và sưởi ấm ở nhiệt độ thấp. | Kuo Jeff Vadose zone soil remediation Practical Design Calculations for Groundwater and Soil Remediation Boca Raton CRC Press LLC 1999 chapter five Vadose zone soil remediation This chapter illustrates important design calculations for commonly used in situ and above-ground soil remediation techniques. The treatment processes covered include soil vapor extraction soil bioremediation soil washing and low-temperature heating. V.1 Soil vapor extraction V.1.1 Introduction Description of the soil venting process Soil vapor extraction SVE also known as soil venting in situ vacuum extraction in situ volatilization or soil vapor stripping has become a very popular remediation technique for soil contaminated with VOCs. The process strips volatile organic constituents from contaminated soil by inducing an air flow through the contaminated zone. The air flow is created by a vacuum pump often called a blower through a single well or network of wells. As the soil vapor is swept away from the voids of the vadose zone fresh air is naturally through passive venting wells or air infiltration or mechanically through air injection wells introduced and refills the voids. This flux of the fresh air will 1 disrupt the existing partition of the contaminants among the void soil moisture and soil grain surface by promoting volatilization of the adsorbed and dissolved phase of contaminants 2 provide oxygen to indigenous microorganisms for biodegradation of the contaminants and 3 carry away the toxic metabolic by-products generated from the biodegradation process. The extracted air is usually laden with VOCs and brought to the ground surface by the vacuum blower. Treatment of the extracted vapor is normally required. Design calculations for the VOC-laden air treatment are covered in Chapter seven. 1999 CRC Press LLC Major components of an SVE system Major components of a typical soil venting system include vapor extraction well s vacuum blower s moisture removal device knock-out drum offgas