Identification of Industrial Sewage Sludge based on Heavy Metal Profiles: A Case Study of Printing and Dyeing Industry

The illegal disposal of industrial sewage sludge has caused serious environmental pollution. To develop identification techniques of industrial sewage sludge based on the characteristic fingerprints carried by sewage sludge itself is a promising method that is helpful to clarify the responsibility of illegal enterprises. In this study, heavy metal composition and speciation of sewage sludge from industries (including printing and dyeing industry and other industries) and municipal sewage treatment plant located in eastern China were determined and their performance of classification was evaluated by principal component analysis (PCA) and linear discrimination analysis (LDA). Results showed that heavy metal composition and speciation can be an effective tool for distinguishing sewage sludge between printing and dyeing industry and other industries, with an accuracy rate of 82.9% and 100%, respectively. Antimony (Sb) and zinc (Zn) are two characteristic heavy metals, which can be used to identity sewage sludge in printing and dyeing sub-industries with an accuracy rate of 90%. The combination of these three methods may be a precise and promising tool for identification of sewage sludge between industries and sub-industries. This study developed a potential method for tracing the industrial sources of sewage sludge and establishing the identification database of industrial sewage sludge, and provided technical support for the government to supervise the illegal dumping and disposal of industrial sewage sludge.

Co-pelletization of Industrial Sewage Sludge and Rice Straw: Characteristics and Economic Analysis

The disposal of industrial sewage sludge is one of the most serious environmental problems in Thailand. Moreover, the disposal expense is considered as the production cost to the manufacturer. Therefore, the concept of waste-to-energy technology (WTE) is applied to solve this problem. This study aimed to study the effect of sewage sludge and rice straw proportions on the properties of co-pellets. Here, the production of co-pelleted sewage sludge from the canned food industry, combined with biomass (rice straw), was performed using a lab-scale pelletization machine. The pellets consisted of sewage sludge (SS) and rice straw (RS) with sewage sludge ratios of RS100:SS0, RS50:SS50, RS35:SS65, RS25:SS75, and RS0:SS100. The co-pellets produced were characterized for physicochemical properties and calorific heating values. In addition, the benefit to cost ratio (B/C), internal rate of return (IRR), and payback period (PB) from the utilization of co-pellets were studied. The results suggest that the proportion of sewage sludge affects the properties of the co-pellets. The optimum sewage sludge to rice straw ratio at RS0:SS100is considered to have good fuel combustion properties. It is suitable for the production of co-pellets because of its high volatility and low ash slagging content

THE PHYSIOLOGICAL AND CELLULAR STUDY OF TRITICUM TURGIDUM GROWN IN AMENDED SOIL WITH SEWAGE SLUDGE (URBAN AND INDUSTRIAL) IN OPEN FIELDS UNDER SEMI-ARID CLIMATE CONDITIONS

A field experiment was conducted to demonstrate the beneficial and negative aspects of sewage sludge application on wheat and to determine the way of heavy metals in the sludge-soil-plant system. Two types of sewage sludge (urban and industrial) were applied at different rates (5, 25, 50 and 100 t dry matter (DM) per ha). Results showed that growth and yield have been improved by sewage sludge use. However, sewage sludge applications modified the content of heavy metals in plant tissues especially for industrial sewage sludge and high rates where significant accumulations including Co, Cr and Pb, were detected mainly in the roots. This has been coupled by an alteration of the root cellular ultra-structure and the presence of heavy metal deposition as electron-dense granules and crystals.