Assessment of factors contributing on early rotting of Chromated Copper Arsenate treated utility power distribution wood poles in Tanzania

Abstract

The study aimed to assess the factors contributing to the premature decay of Chromated Copper Arsenate (CCA) treated utility power distribution wooden poles in Tanzania. Deteriorated poles samples from various regions in Tanzania were analyzed using handheld X-ray spectrometry to quantify the retention of CCA preservative chemicals. The ages of these poles were estimated based on annual growth rings. The findings indicated that premature failure of CCA treated wooden poles is attributed to an imbalance in the chemical composition of the preservative solution. The study found that CuO retention in most samples ranged between 10-18 kg/m3, significant lower that the 24 kg/m3 minimum required by standards. Insufficient As2O5 levels and premature timber harvesting were also contributing factors. The study concluded that early decay of CCA treated wooden poles is multifactorial, with the primary cause identified as an inadequate ratio of chemical elements in the CCA compound. This imbalance is characterized by reduced levels of Copper and Arsenate and an elevated content of Chromium (a bonding agent), likely adjusted to balance the minimum retention values. Additionally, premature timber harvesting and treatment with high moisture content aggravate the degradation process. The study also highlights the need for stricter treatment protocols and suggests policy intervention to enhance pole durability. Implementing these changes could reduce TANESCO’s annual expenditure on replacements, improve infrastructure reliability, and enhance worker safety. Further research is needed to assess alternative preservatives and examine the impact of environmental conditions on decay rates.