Evaluating the mobility of toxic metals in untreated industrial wastewater sludge using a BCR sequential extraction procedure and a leaching test

Abstract

The distribution and speciation of toxic metals in industrial wastewater sludge (IWS) was investigated. In this work, the modified BCR three-stage sequential extraction procedure was applied to the fractionation of Cr Pb Ni, and Cd in untreated industrial wastewater sludge from industrial sites in Hyderabad (Pakistan). The extracts were analyzed using electrothermal atomic absorption spectrometry. The procedure was evaluated using a certified reference material for soil mixed with sewage sludge BCR 483. The results from the partitioning study indicate that more easily mobilized forms (acid exchangeable) of Cd were dominant. The oxidizable fraction was dominant for all four toxic metals. Metal recovery was good, with <4% difference between the total metal recovered through the extractant steps and the total metal determined after microwave digestion. Lixiviation tests (DIN 38414-S4) were used to evaluate the leaching of toxic species from IWS, and it was observed that levels of leachable toxic metals were low compared to the amount of metal extracted in the exchangeable fraction of the BCR protocol.

Speciation of heavy metals in electroplating industry sludge and wastewater residue using inductively coupled plasma

“…Cd is the least abundant metal in the plating wastes, when comparing with other available metals. The exchangeable fraction of Cd is 6-14 % in wastewater residue samples and traces in sludge samples, similar to the observation by Kazi, et al, (2005) in wastewater sludge. About 50 % of acid extractable fractions constitute the samples 3 and 4 where as 32 and 10 % in samples 1 and 2 respectively.…”

“…Method developed by Tessier, et al, (1979) is the one widely used for this purpose. Kazi, et al, (2005) evaluates the mobility of toxic metals in untreated industrial wastewater sludge. The results from the partitioning study indicate that more easily mobilized forms (acid exchangeable) of Cd were dominant.…”

Total and extractable heavy metal, phosphorous and sulfur concentrations in slaker grits from the causticizing process of a pulp mill for use as a soil amendment

“…From a utilization point of view, the low level of organic matter in the slaker grits is a favourable phenomenon since, if present, the organic matter may form complexes with toxic heavy metals. Furthermore, the biodegradation of organic matter under oxidizing conditions can lead to the release of the metals bound to these organic components when waste material is used as a soil conditioner (Kazi et al, 2002). Except for Mn (30.3%), Fe (1.1%), Co (33.7%), Ni (36.9%), Ti (17.7%) and S (2.8%), the proportion of Cr (90.8%), V (75.4%), Zn (78.3%), Ba (62.1%), Al (99.4%) and P (99.8%) was highest in this fraction.…”

FRACTIONATION OF HEAVY METALS (Pb, Cr AND Cd) IN MUNICIPAL SEWAGE SLUGES FROM PODLASIE PROVINCE

“…62%) of Cr in the discussed fraction using BCR method. Kazi et al [2005], noted 41% of pseudo-total chromium in residual fraction. According to the authors, such a content indicates that this element occurs in a high degree as sulphides.…”

“…Metals bound to this fraction can be easily released after application of sludge into soil, due to the small bond strength [Wang et al 2008, Kazi et al 2005], during fractionation of sludges from the treatment plant located in Hyderabad city (Pakistan), with BCR method, have noted 4% of pseudo-total lead The most of lead content (89.9% of pseudototal content) in mobile pool (F1+F2+F3), i.e. available and potentially available for plants, was noted in the sludge from plant in Knyszyn.…”