INVESTIGATING THE PHYSICO-CHEMICAL CHARACTERIZATION AND SOME SELECTED HEAVY METALS OF THE SLUDGE RELEASED FROM INDUSTRIAL PARK: THE CASE OF HAWASSA INDUSTRIAL PARK, ETHIOPIA

ABSTRACT Textile sludge is an inevitable byproduct generated from Common Effluent Treatment Plants (CETPs). Presently ,excess sludge is left over from zero-liquid-discharge plant, often get filled in the sludge may contain unsafe levels of heavy metals and pollutants, that are very active to circulate on environment and its accumulation is a burden to the industry and affects environmental quality and human health. Therefore, the purpose of this study was to investigate the physio-chemical characteristics and the levels of some heavy metals of the sludge released from Hawassa textile industrial park. Accordingly, sludge sample was collected by randomly from temporary discharge point and stored in plastic bag by applying Quartering method. And send to laboratory to determine the content of pH; Temperature; Total dissolved solid (TDS); Chemical Oxygen Demand (COD) ; Total Alkalinity ;Dissolved Oxygen (DO); Electrical Conductivity (EC) ; Total Suspended Solid (TSS) ; Total Nitrogen (TN ); Total Phosphors (TP); Potassium (K); Magnesium (Mg); Calcium (Ca); AmmoniaNitrogen (NH3-N) ; Sulphate (SO42-) ; Phosphate (PO43-); were determined by using spectrophotometer and heavy metals determined using Atomic Absorption Spectrometer(AAS). The result showed the concentration of pH; TDS ; COD ; Total alkalinity ; DO and EC were 8.11 ; 26.7 ; 1762+52.2mg/L ; 996+125.03mg/L ; 717+44.23mg/L ; 17+0.01mg/L ; 2.96+0.2ms/cm respectively. TSS 236+61.01mg/L; BOD 331.11+36.71mg/L correspondingly. TN ; NH3-N ; TP ; SO4 2 ; K ; Ca and Mg found to be 0.21+0.03; 0.026+0.02; 0.01+0.0; 0.03+0.02; 12.4+1.06; 52+4.02 and 26+5.3mg/L correspondingly. The proximate such as moisture content; volatile /fixed solid; total organic carbon and matter content were 80.85+1.7; 40.2+1.81; 59.8+1.81 ; 4.82+0.36 and 8.34 ±0.71 % respectively . The concentration of heavy metal concentration values in the sample sludge were ranked in the following order: Fe > Zn > Cr > Ni > Co > Cd > Cu > Pb accordingly 8.46+0.18; 4.11+0.41; 4.02+1.15; 2.37+0.72; 1.93+0.01; 1.51+0.7; 1.40+0.1and 1.24+0.13mg/kg respectively. The obtained results found to be within the regulatory limits nature of sludge of Indian Hazardous Waste Management Rules (Amendment rules, 2003), whereas below the permissible standards guidelines for maximum limit proposed for agriculture soil set by FAO/WHO. Therefore, adopt a suitable management option requires an extensive investigating the characterization of physicochemical parameters and pre-treatment process technology for reducing the amount of some heavy metal toxicity before the sludge can be used for agricultural land fertilizer or disposed.