As an expert on the risks associated with the land application of America's sewage sludge, I was impressed with Rose's Biosolids chapter. I wish the chapter had been longer and had emphasized how federal and state regulatory agencies work with those corporations that profit from sludge spreading to deceive legislators, the media, farmers, and the public on the short- and long-term risks of this practice. See www.sludgefacts.org. Since the publication of my 2005 paper disturbing new data about the environmental and health risks of spreading sludge on farmland is reported almost every month. US EPA officials continue to ignore and deride complaints by sludge-exposed rural residents who ask for help. Many of them live in low-income and/or minority neighborhoods that have neither the political or legal clout to restrict land application. EPA ignores or covers up incidents of ground water pollution, soil degradation, cattle deaths and fly infestations, all linked to sludge spreading. Occasionally EPA send someone to a problem area to investigate. But their response is always that all is well, because no rules were broken. Of course. The US rules governing sludge spreading are the most lenient of any industrialized nation, which means that almost any hazardous material can legally be used as a soil amendment.

Rose's Biosolids chapter includes one factual error. Although admitting that Class B sludge is risky, she appears to be promoting the use of "pasteurized" Class A EQ sludge. Class A sludge is not pasteurized. Many experts believe that long-term, the unregulated use of Class A sludge is more risky, especially if this material is stored for longer than three weeks, because of pathogen re-growth. US Sludge compost can legally contain 41 mg/kg of arsenic, 39 mg/kg of cadmium, 1,500 mg/kg of copper, 300 mg/kg of lead, 17 mg/kg of mercury, 420 mg/kg of nickel, 2,800 mg/kg of zinc, and any amount of hexavalent chromium, molybdenum, and dioxins, besides pathogens that have not been inactivated in the process. Yet this material can legally be spread anytime, anywhere, in any amount, on any soil.

There is a great deal of difference between the night soil of rural China, Africa, and India, and the sewage sludge of the US. Most of this country's sludge is generated in large urban industrialized centers. Industries that used to dump their hazardous and persistent pollutants into rivers and oceans, are now dumping them into sewage treatment plants. As the sewage is "cleaned" most of these same pollutants concentrate in the resulting sludge. Every business, hospital, institution, metal plating shop in the country can legally dump 33 pounds of hazardous waste into the sewers, every month, and many probably dump more.

The current US system of managing human and industrial waste makes no ecological or economic sense; except of course for the large cities that need to get rid of their daily sludge and the corporations that profit from spreading this poisonous complex and unpredictable mixture on rural farmland. Pollutants don't go away. Land application is not "recycling". It is pollution transfer. Does it really make sense to spend millions to build a sewage treatment plant that removes pollutants from sewage, only to spread these same pollutants back on the land where they can affect humans, animals, groundwater, and degrade farmland? Sometimes I wonder if ocean dumping of sludge (beyond the continental shelf) wasn't perhaps a better solution.

The real solution? Africa, India, and China show us the way. Use sludge as a renewable feedstock for clean energy. Rose mentions how in one French town buses are run on sludge; in a Swedish town this is also done. And in Flint, Michigan, the mayor, has introduced the same idea. In St Paul, Minnesota, sludge is managed in three fluodized -bed incinerators at great savings and reduction in air emissions. Biogas, anaerobic digesters, by all means! China and Germany have the right idea.
Yes, there is a need for sanitation in developing countries. Most important is the availability of clean drinking water. What good is a clean latrine and hand washing, if the material is just dumped in the nearest river which also serves as a source of drinking water?
As Rose points out, waterborne systems don't work in regions where water is scarce. But standard sewage treatment plants do not make sense, either. They are expensive to build, use a great deal of energy and water, they cannot remove emerging contaminants from the waste water, and produce sludge that needs to be managed some way.

India's Pathak had the right idea with his Sulabh Shauchaleaya, a kind of composting toilet, which should be promoted in un-sewered and water-scarce regions of the world. However, in this country, where most of the sludge is produced in large cities, composting toilets are not the answer. Congress just appropriated another $ 200 billion over the next ten years to build new sewage treatment plants. Perhaps some of those funds can be used to build digesters or low-emission incinerators on site to manage sludge, so that our fields, farms, and forests will no longer be spread with industrial pollutants hiding in "biosolids."