| WASTEWATER DISINFECTION It Doesn't Work By Jim Bynum Retired Safety Consultant DAVID GATTIE AND DAVID LEWIS (2003) A High-Level Disinfection Standard for Land-Applied Lewis was a highly respected microbiologist at EPA. Once he exposed the lies supporting sewage effluent recycling, EPA and the waste industry have brought discredit upon his name as an expert witness in the legal system. I know. It is in the public records, I had to write Lewis a letter to that effect when I desperately required his expert testimony in court. Lewis mentioned the high levels of E. coli I required expert testimony for in Sludge Magic at the EPA, The Journal of Commerce; January 27, 1999. Today, Lewis can not even comment on a sludge issue because of pending court action. You will notice the disinfection levels discussed in this study are achieved in a medical laboratory -- not in a wastewater treatment plant. EPA acknowledges that low levels of disinfection will injure coliforms. EPA stated in 1989, "Because total coliforms are common inhabitants of ambient water and may be injured by environmental stresses (e.g., lack of nutrients) and water treatment (e.g., chlorine disinfection) in a manner similar to most bacterial pathogens and many viral enteric pathogens, EPA considers them a useful indicator of these pathogens." It is useful to hide the exposure danger, in effect the injured bacteria become viable, but nonculturable by standard laboratory methods. There is one more problem. "Unlike other E. coli, isolates of serotype O157:H7 do not ferment D-sorbitol within 24 h, lack-glucuronidase activity, and do not grow at 45.5°C" Excerpt Current federal standards for pathogen reduction in sewage sludge are based on levels of indicator organisms, such as Escherichia coli and Salmonella. [fecal and coliform bacteria] Because all federal and state requirements are based on less resistant indicator organisms, it is not known whether current methods, including aerobic and anaerobic digestion, heat treatment, lime stabilization, and composting, could achieve high-level disinfection. Table 1. Disinfection levels required to kill pathogens in sewage sludges.(a) ------------------------------------------------------------------------------------------------------------------------- Group Disinfection level required ------------------------------------------------------------------------------------------------------------------------- Bacterial endospores (e.g., Bacillus anthracis) Nonenveloped viruses (e.g., Norovirus, Coxsackie, Rotavirus) Helminths (e.g., Ascaris, Toxocara) Protozoa (e.g., Cryptosporidium, Giardia) Mycobacteria (e.g., M. tuberculosis) Fungi (e.g., Candida) Vegetative bacteria (e.g., Staphylococcus, Salmonella) [coliform] Enveloped viruses (e.g., hepatitis B, HIV, influenza) ------------------------------------------------------------------------------------------------------------------------- Data from the Association for the Advancement of Medical Instrumentation (AAMI 1994). (a) Disinfection levels are based on susceptibilities to liquid chemical germicides; groups increase similarly in resistance to heat, with enveloped viruses being the most sensitive and bacterial endospores the most resistant. Most bacteria found in sewage sludge produce either endotoxins or exotoxins, both of which can cause severe illness or death. As sludges decompose, toxins can leach into groundwater, enter surface water runoff, and be carried away in airborne dusts. Considering that tons of decomposing sewage sludge per acre are often applied to hundreds or thousands of acres many times a year, land-application sites have a potential for producing and exporting large quantities of toxins. Unlike most exotoxins, endotoxins are heat stable even upon autoclaving (Baines 2000). They can, however, be inactivated with dry heat at > 200oC for 1 hr (Williams 2001). Traces of endotoxins in food and water can cause headaches, fever, fatigue, and severe gastrointestinal symptoms; however, their primary target is the lungs. In addition to the former symptoms, inhaling endotoxin-contaminated dusts can cause acute airflow obstruction, shock, and even death. Chronic respiratory effects can also develop [American Conference of Government Industrial Hygienists (ACGIH) 1999]. Nearby residents exposed to dusts from land-application sites report many of the same symptoms of endotoxin poisoning that have been documented among sewage treatment plant workers. These include flu-like symptoms, nausea, vomiting, diarrhea, headaches, and difficulty breathing (Lewis et al. 2002). Rylander (1987) proposed occupational exposure limits to endotoxin-contaminated cotton dusts. Based on average air concentrations over an 8- to 10-hr workday, he suggested limits ranging from 200 EU/m3 to prevent airway inflammation to 20,000 EU/m3 to avoid toxic pneumonitis. The exposure levels of endotoxin-contaminated aerosols with sewage treatment plant workers have ranged from 80 to 4,100 EU/m3 (Liesvuori et al. 1994). The toxins, however, have a greater effect on people with immune systems compromised by injury or illness (Baines 2000). http://www.ehponline.org/members/2003/6207/6207.pdf Detection of Pathogens (1998) Deadly Deceit CHAPTER 7, Deadly Microbes D. Strauch in his 1991 paper, "Survial of pathogenic micro-organisms and parasite in extreta, manure and sewage sludge" reported that two groups of researchers had found that pathogenic disease organisms will be taken up inside the food crops. In other words, it will do little good to wash the outside of fresh vegetables and fruit when the pathogenic bacteria, viruses and worms from the sludge can be inside the plant. Strauch concluded in his report that, "In any case, the agricultural utilization of hygienically dubious sewage sludge poses a risk for the whole national economy." It has been recognized in Germany, at least since D. Strauch published his paper in 1991, that" most pathogenic agents can survive the treatment process" and the sewage treatment process causes some of the pathogenic disease organisms to be absorbed or enclosed in faecal particles during the treatment process. "Therefore," according to Strauch, "sewage sludge is rightly described as a concentration of pathogens." In a personal interview with scientist David Lewis of the EPA, who is a whistleblower, more disturbing facts about pathogens and their detection came to light including the information about the AIDs virus. According to Lewis, standard test methods underestimate the number of water repellant contaminates. In looking at the aids virus found on medical and dental tools, Lewis discovered that the HIV virus, when it was covered with a water repellant lubricant such as silicone, was still infectious after several days. The water repellant lubricants such as silicon and petroleum products cover the pathogens and prevent them from being found by standard test methods. It was only when he dissolved the lubricants with acetone or other solvents, that the pathogens showed up in tests. "Body fluids also break down the lubricants surrounding the contaminates," he said. Lewis has brought these facts to the attention of the Food and Drug Administration who is supposed to be setting up a committee to study the problem. "The problem of pathogen detection in sludge, according to Lewis, "is that the sewage treatment process changes the outside crust of the aggregates in sludge and only the pathogens on the outside of the aggregates are measured by standard tests." He says that most of the microbes are trapped inside the aggregates. When ultrasound was used to break open the aggregates of sludge the trapped microbes were revealed. In effect, it appears that the treatment processes hide most of the pathogens rather than destroying them. Straub, Pepper and Gerba say that the list of pathogens are not constant but keep changing: As advances in analytical techniques and changes in society have occurred, new pathogens are recognized and the significance of well-known ones change. Microorganisms are subject to mutation and evolution, allowing for adaptation to changes in the environment. In addition, many pathogens are viable but nonculturable by current techniques (Rozak and Colwell 1987), and actual concentrations in sludge are probably underestimated.(p. 58) They add further: Thus, no assessment of the risks associated with the land application of sewage sludge can ever be considered complete when dealing with microorganisms. As new agents are discovered and a greater understanding of their ecology is developed, we must be willing to reevaluate previous assumptions. (p. 58). According to the article "Pathogen Destruction and Biosolids Composting" in Biocycle of June of 1996, "There is some evidence that coliforms and Salmonella sp. can survive prolonged exposure to temperatures of 55 C." They cite a study done by Droffner and Brinton (1995) using DNA gene probes, where they detected E. coli and Salmonella sp. in samples collected from an in-vessel composting facility after the first 15 days of active composting at a temperature above 55 C. In Table 5-4 Processes to Further Reduce Pathogens in A Plain English Guide to the EPA Part 503 Biosolids Rule, composting time and temperature requirements for within-vessel composting method was 55 C or higher for three days! Droffner and Brinton found that it took 56 days and 90 days for the densities of Salmonella sp. and E. Coli, respectively, to decline below the detection limit...These investigators also "cite evidence of mutant strains of E. coli and Salmonella sp. resistant to thermal environments in composting." (p. 68) " |