Author: Muhammad Ahmad

In Chapter 6, top‐down BACT analyses for criteria pollutants were presented for a gas turbine facility (Section 6.6). As an example, here we present the TACs and costs per ton pollutant of particulate matter removed against exhaust gas rate and boiler steam capacity for four control options: (i) multi‐cyclones (MC), (ii) Venturi scrubber (VS), (iii) electrostatic…

Costs associated with poor environmental and societal performance can be very large. Waste disposal feed, permitting costs, and liability costs can all be substantial. Wasted raw material, waste energy, and reduced manufacturing throughput are also consequences of wastes and emissions. Corporate image and relationships with workers and communities can suffer if performance is substandard. But…

Industrial air pollution prevention (P2) efforts have focused on both source and waste reduction, and on reuse and recycling. A key approach is preventing air pollution within a company’s manufacturing processes, particularly in chemical process industries. Frequently, we fail to consider that control systems themselves are industrial processes that consume energy and can emit significant pollutants…

Emissions of nitrogen oxides (NOx), sulfur dioxide (SO2), VOCs, and mercury, as well as carbon dioxide (CO2), and hotter climate undermine public health, the environment, and the overall state economy. The worst air quality in the United States is in California, a state known for its efforts to raise environmental standards, cut greenhouse gas emissions,…

In July 1996, a paper company located on the west bank of the Mississippi River undertook a program to eliminate the discharge of industrial wastewater to the river. A wastewater recycling system consisting of pumps, surge tank, and filtration system reduced discharges by 99%. The successful pollution prevention includes the annual elimination of 562 million gal of…

Like the three evaporators, the two concentrators are vertical‐tube, falling‐film design. Rather than using a vapor compressor to drive the system, the concentrator is operated with steam generated by the recovery boiler. The evaporation process in the concentrators is essentially the same as in the evaporators, but the effluent is concentrated further, to about 67%…

The heart of the zero effluent system is three vertical‐tube, falling‐film vapor compression evaporators which operate as explained (Das 2005). At 100 ft tall, and with thousands of square feet of heat transfer surface, this is the largest train of mechanical vapor recompression evaporators in the world. The evaporators concentrate effluent from 2% solids to 35% solids,…

The first unit operation to receive pulp mill wastewater is the floatation clarifiers. Since removal of fiber is very important to the performance of the evaporators, the mill decided to install two clarifiers instead of one. This allows for maximum removal efficiency and flexibility. Chemicals are added to aid in flocculation and floatation of the…

The $250 million Millar Western Meadow Lake Mill is located on a 247‐acre site about 200 miles northwest of Saskatoon, Saskatchewan. It uses mechanical action supplemented by mild chemicals to turn aspen wood chips into bleached chemi‐thermomechanical pulp (BCTMP), about 240 000 MT/Y.2 More efficient than the kraft process, this approach uses half the trees to make the same amount…

Introduction Every day, water‐cooled thermoelectric power plants in the United States withdraw from 60 billion to 170 billion gal of freshwater from rivers, lakes, streams, and aquifers, and consumes from 2.8 billion to 5.9 billion gal of that water. Freshwater withdrawals for cooling in thermoelectric power production account for about 40% of all withdrawals, essentially the same amount as withdrawals for agricultural…