Biological Dehalogenation of Kraft Mill Wastewaters

Abstract

A single-stage aerobic biological treatment system was developed specifically to convert organically bound chlorine to inorganic chloride. In initial laboratory tests, greater than 90% reduction of AOX was achieved in synthetic dichlorophenol, commercial pentachlorophenol, and combined kraft wastewaters, and less than a week was required for startup/acclimation. A six-month field test of the process on a pentachlorophenol wastewater was very successful under highly variable influent conditions. No chlorinated byproducts were detected, and measurements strongly indicated that dehalogenation had occurred. Recent experiments found Cl/El wastewater to be most easily treatable by the aerobic process, followed by combined lagoon influent, El wastewater, and finally lagoon effluent. However, results have indicated that application of the treatment process to kraft AOX reduction can become feasible only if further process improvements can be defined.

An Assessment of Variability of Pulp Mill Wastewater Treatment System Bacterial Communities using Molecular Methods

“…To treat pulp mill effluents, secondary wastewater treatment systems have been used for decades for the reduction of BOD (biochemical oxygen demand), COD (chemical oxygen demand), AOX (adsorbable organic halogens), and resin acids in the final effluent (Lindstrom and Mohamed 1988;Bryant and Berkley 1991;Kostyal et al 1997). The two main types of biotreatment processes employed by the pulp and paper industry are the aerated lagoon (aerated stabilization basin) and the activated sludge system.…”

Influence of bleaching technologies on the aerobic biodegradability of effluents from Eucalyptus kraft pulps factories

“…The biological removal of AOX in aerated systems seems to be more difficult for hardwood pulp bleaching effluents (Bryant and Amy, 1991), no removals being reported for Eucalyptus pulp bleaching effluents (Boyden et al, 1994). Furthermore, the molecular weight of AOX compounds influences biodegradation as the biodegradability is higher for low molecular weight fractions (Bryant et al, 1987).…”

Redução da produção de lodo no tratamento aeróbio de efluentes da indústria de celulose e papel

“…Também observaram que o material não removido, era formado de compostos de elevado peso molecular (>1.000 Da). Os compostos monoclorofenóis, foram reduzidos de 45 à 89 %; os diclorofenóis de 24 a 93%; os triclorofenóis de 21 a 67%, os (LEUENBERGER et al, 1985;BRYANT & BARKLEY, 1991;TRIPATHI, 1995;ZHENG & ALLEN, 1996;TRIPATHI & ALLEN, 1997). Estas rotas de remoção de organoclorados são brevemente comentadas a seguir e encontram-se esquematizadas na Figura 2.6.…”