Dioxin water treatment process

The selective removal of very low levels of dioxin from large volumes of process wastewater has become a concern to a number of companies and municipalities. Very little has been reported on how dioxin behaves in conventional water treatment processes (2-3). The work of Thebault, Cases, and Fiessinger suggested that alum flocculation would be marginally effective for the removal of dioxin. Our need to remove up to several parts per trillion dioxin from water in the lagoon prompted us to evaluate flocculation as a faster and more cost effective treatment for dioxin removal. 

Catalyst fines are removed with a newly developed hot-gas catalyst filter or alternatively by wastewater treatment that meets even the strictest regulations for copper, dioxins and furanes. The environmentally friendly process uses recycle gas, which is fed back to the reactor after condensing EDC and water. After EDC removal, the process water meets even the most stringent environmental requirements. 

One can speculate that ozone may be useful in the treatment of heavily contaminated bodies of water. In this use, pipes and ozone generators will be installed to provide a continuous supply of ozone to the water. At first, ozone will kill all current life. Next, it should oxidize the residual dissolved organic material remaining from past contamination. As ozone treatment continues, the sludge on the bottom will be oxidized killing and removing all bacteria and plant life. With sufficient ozone treatment, the water and bottom will become totally sterile and free from all organic contamination. While not demonstrated, this process has the potential to eliminate toxic materials such as herbicides, pesticides, DDT, DDE, dioxin and other POPs that would otherwise persist in the lake for decades. 

These processes use very little water and do not call for high capital investment for the treatment of aqueous effluent. However, they do call for increasingly heavy investment in air treatment in order to comply with the increasingly stringent air discharge limits these apply not only to cadmium but also to nickel, CO, CO2, NOx, dioxins and flirans. 

The water from the flue gas wash flows through a wastewater treatment plant in which heavy metals and dioxins are precipitated and filtered out. In this process, about 1001 of sludge arise per year. The sludge is then drained in a filter press. One percent of the remaining sludge still contains heavy metals and must be disposed of in an underground deposit. 

On the basis of the PAH rejections of over 90%, the permeate would be expected to be acceptable for discharge to POTWs (Publically Owned Treatment Works) with little or no polishing. Other pollutants found in ccaitaminated waters at wood treatment facilities (e.g., polychlorinated dioxins and furans) also are concentrated in the reject stream. Other constituents commonly encountered at such sites including colloidal oils and suspended solids are also extensively removed by the membrane process. Removal efficiencies for oil and grease were 93%. Suspended solids were removed to nrai-detectable levels. These materials did not appear to have an adverse effect on the filtration process. 

WAO is a strong candidate for the treatment of both RRS and MMD neutralents because the process requires only the addition of water and air or oxygen, and no dioxins are formed (in fact, Battelle claims dioxins are destroyed). WAO is most effective on dilute aqueous solutions (e.g., chloroform must be diluted to less than 20,0(X) mg/L), and RRS and MMD neutralents might have to be diluted with water to... 

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