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TREATMENT WETLANDS - CHAPTER 6

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Tần số dữ liệu ảnh hưởng đến mức độ phân tán dữ liệu. Thay đổi đa dạng giảm hàng ngày, hàng tuần, hàng tháng, hàng năm, nhưng xu hướng trung tâm là như nhau. Ví dụ, các hệ số biến đổi phốt pho tổng số hơn bốn năm tại Brighton, Ontario, hàng tuần 89%, 83% hàng tháng, và 19% hàng năm. Nhiều yếu tố góp phần biến đổi ngẫu nhiên trong nồng độ đầu ra từ một vùng đất ngập nước xử lý duy nhất. Biến đổi này thường không nhỏ, với hệ số biến thể của 20% -60% là. | 6 Representing Treatment Performance This chapter examines the available means of collecting and analyzing the large amount of performance data that now exists for treatment wetlands. Wetlands are open systems heavily influenced by environmental factors. This makes them more complex than other types of biological treatment reactors activated sludge trickling filters described in the environmental engineering literature. Nevertheless attempts have been made to adapt models from these other technologies to treatment wetlands Burgoon et al. 1999 McBride and Tanner 2000 Langergraber 2001 Rousseau et al. 2005b Wu and Huang 2006 . Wetlands are dominated by biomass storage compartments that are very large relative to pollutant mass in the water column again different than other biological reactors . These biomass storage compartments are affected by seasonal cycles that are different than temperature cycles. Treatment performance is represented by two components the central treatment tendency for a wetland or group of wetlands and the anticipated variability away from that central tendency. Central tendencies are driven by flows and concentrations in concert with environmental factors. Random events within the wetland will produce stochastic variations in effluent performance. Both must be assessed to describe treatment performance in constructed wetlands. Different types of wetlands e.g. wetland configuration vegetative community function differently. Therefore a set of universal parameters for describing treatment performance in wetlands is not to be expected. 6.1 VARIABILITY IN TREATMENT WETLANDS Two types of variability are of interest for understanding and design of treatment wetlands. First it is necessary to understand the scatter of performances for an individual wetland around either the central tendency of data or the model characterization of that central tendency. This is the intrasystem or internal variability and it is needed to understand the excursions .