Search

Dewatered sludges from twenty-two sewage treatment facilities were characterized to develop the quality control indices in India. This study used fertilizer index (FI) and clean index (CI) as a tool for categorizing sludge utilization into different classes (A, B, C and limited use classes LU-1, LU-2, LU-3) by their fertilizing potential, toxicity level, pathogen presence, and vector attraction reduction criteria. The findings revealed that total P (as P2O5), total N, and K (as K2O) in the sludge samples ranged from 0.9 to 5.7%, 1.2 to 3.8%, and 0.1 to 1.5%, respectively. Moreover, all sludges belong to Class C and lower category due to the presence of toxic metals and pathogens. The helminth eggs were found in the range of 25–1450 Numbers/4gTS in sludge samples. The highest number of helminth eggs of 1450/4 g of TS was found in the fecal sludge. The specific oxygen uptake rate (SOUR) values in the sludge samples varied from 0.3 to 4.9, with a median value of 1.3 and an RSD of 86% is way too high. It indicates that the sludge samples need further treatment to be less attractive as a food source for vectors and rodents. However, sludge samples have fertilizing potential and FI values ranges from 4.1 to 4.9, and CI value ranges from 2.5 to 5.0. It indicates that compost is best in quality and has high-fertilizer potential and low heavy-metal content, which is suitable for high-value crops such as organic farming. Further sludge treatment using typical composting, aerobic or anaerobic digestion, and solar or thermal drying could bring the sludges into the Class A and B categories. [ABSTRACT FROM AUTHOR]

The mitigation of sewage sludge is quite challenging, as the general method of disposal of sludge after being treated at the waste water treatment plant is landfilling, which makes land unfit for either agricultural or commercial growth. The disposal of sewage sludge in India presents significant environmental challenges due to increasing urbanization and limited land availability. Understanding the potential use of sewage sludge as a construction material has been verified to be the best method of recycling and environmental protection. The possible use of sewage sludge in civil engineering firms is discussed in this paper, along with the various testing methods. Carefully treated sewage sludge is proven to be an effective material, either as a replacement for cement or aggregates in construction. This paper indicates that sewage sludge can be effectively utilized as a raw material in concrete, contributing to resource conservation and environmental sustainability. It supports the feasibility of using sewage sludge in various construction applications, such as eco-cement, bricks, and lightweight aggregates, offering an eco-friendly solution to sewage sludge disposal. [ABSTRACT FROM AUTHOR]