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Nutrient Farming and Traditional Removal: An Economic Comparison (Werf Report)

The purpose of this study was to assess the economic feasibility of using large-scale, restored wetlands to assist publicly owned treatment works (POTWs) in meeting the U.S. Environmental Protection Agency’s (USEPA) recommended criteria for nutrients, specifically, total nitrogen (2.18 mg/l) and total phosphorous (0.076 mg/l). The assessment compares the cost of nutrient control by advanced wastewater treatment technology to that of wetland treatment technology. The comparison was based on several economic factors: annual operating costs, average costs, marginal costs, and present value. To explore the economic relationship between wastewater and treatment wetlands and to quantify the magnitude of wetland area needed, a case study was developed using the seven water reclamation plants (WRPs) owned and operated by the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) and proposed treatment wetlands located adjacent to the Illinois River in the upper Illinois River watershed. Cost functions for both technologies were developed. Using these functions, the economic characteristics of the two technologies were compared assuming, first, that the USEPA’s proposed nutrient criteria would be enacted as the enforceable water quality standard by the state regulator, and, second, that a less stringent standard would be established (3.0 mg/l TN and 1.0 mg/l TP). However, the USEPA’s phosphorus criterion was modified due to the technical difficulty in achieving an effluent concentration of 0.076 mg/l TP. The more stringent phosphorous criterion was set at 0.5 mg/l TP for this comparison study. To meet the future nutrient criteria, the physical facilities of the seven MWRDGC treatment plants must be upgraded to incorporate biological nutrient removal (BNR) technology. A detailed capital cost analysis for the addition of BNR treatment, specifically the 5-stage Bardenpho (with methanol addition), was performed by the MWRDGC for one of its larger WRPs, Calumet. The capital costs for the other plants were estimated using Calumet’s cost formulas and prorated by the design flows. The operating and maintenance (O&M) costs were estimated to add approximately 50% to those for the conventional treatment currently being employed by MWRDGC. The capital costs for upgrading the seven WRPs with the Bardenpho system has been estimated at $1.6 billion with the total present value cost at $2.5 billion.

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The Elements of Agriculture A Book for Young Farmers, with Questions Prepared for the Use of Schools

This is a reproduction of a book published before 1923. This book may have occasional imperfections such as missing or blurred pages, poor pictures, errant marks, etc. that were either part of the original artifact, or were introduced by the scanning process. We believe this work is culturally important, and despite the imperfections, have elected to bring it back into print as part of our continuing commitment to the preservation of printed works worldwide. We appreciate your understanding of the imperfections in the preservation process, and hope you enjoy this valuable book.

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Biological Control by Natural Enemies

Control of insect pests and weeds by their natural enemies offers a proven, feasible, safe, ecological method to pesticidal control. In this concise and fascinating account, Paul DeBach and David Rosen trace the historical background of biological control and examine in detail some of the most famous examples of the discovery of natural enemies and their implementation as active successful biological controls. The book has been thoroughly updated to incorporate recent studies, projects and developments on all aspects of biological control. Conclusions reached, however, remain the same; more biological control is needed – alone and as the mainstay of integrated pest management programmes – if there is to be a diminished use of toxic chemicals which are more expensive, less effective and most importantly, damaging to the environment. This is a second edition of the highly successful book published in 1974 under the same title.

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