Co-application of Red Gypsum and Sewage Sludge on Acidic Tropical Soils

Abstract

The agroenvironmental impact of co-utilization of red gypsum and sewage sludge was investigated. Both laboratory and greenhouse studies were conducted. The treatments were soil + sewage sludge (5% w/w) + red gypsum (0, 2.5, 5, 10, 20, and 40%, w/w). Corn was grown in the greenhouse, and the highest rate of red gypsum application was excluded. The residual calcite in red gypsum was able to increase the pH of the red gypsum-sewage sludge acidic soil system. Hence, gypsum reduced the zinc (Zn) concentrations in the soil solution released by sewage sludge. Phosphorus (P) and potassium (K) were insufficient for corn growth. At the rate of 2.5% red gypsum and 5% sewage sludge application, no dry-matter reduction was observed compared to the control. The uptake of Zn, copper (Cu), and iron (Fe) by the corn plants decreased. Therefore, co-utilization of red gypsum and sewage sludge is a better option than using these by-products separately.

The Physico-Chemical and Mineralogical Characterization of Mg-Rich Synthetic Gypsum Produced in a Rare Earth Refining Plant

“…The risk posed by heavy metals could be reduced with the co-application of organic amendments such as rice husk biochar (RH) and/or empty fruit bunch (EFB). Previous studies show that the sorption of such heavy metals (i.e., Cd, Cu, Zn, Fe, As) has the ability to bind to soil particles, hence reducing the bioavailability of the heavy metals in the soil solution [28][29][30][31]. For example, based on Langmuir's adsorption model, the maximum adsorption capacity (q max ) of EFB biochar for As was 0.42 mg g −1 , which was higher than RH biochar (0.35 mg g −1 ) [32].…”

A Review on Industrial by-products as Materials to Coat Compound Fertilizer

“…Red gypsum was also can be co-utilized with sewage sludge with recommended combination rate of 2.5% red gypsum and 5% sewage sludge for corn cultivation. However, the requirement of P and K of corn need to be observed due to high pH of red gypsum (Fauziah et al, 2011).…”

Physical, Mechanical and Chemical Properties of Dewatered Sewage Sludge and Red Gypsum Mix as a Potential Recycling Product

“…Both wastes are produced in significant amount in Malaysia, i.e. 5 million tonnes/year for SS and 0.5 million tonnes/year for RG as in 2011 and has been increasing ever since [3,4]. These wastes are currently left unused and of no direct beneficial value.…”