Sewage Sludge Incorporating Into Fired Clay Brick: Indoor Air Quality Testing

Abstract

Sewage industry have generated huge amount of sewage sludge. It is found that the amount of sewage sludge generated by Malaysia sewerage companies has reached 5.3 million m3 per year. Sewage sludge (SS) are usually disposed into a landfill or incineration but due to the huge amount of sludge produced and limited availability of lad, it has become an environmental hazard. Thus, this research was conducted to utilize sludge that resulted from the wastewater treatment plant into fired clay brick as well as contributed to other alternative disposal method for the sludge. This research focuses on the investigation of indoor air quality of fired clay brick incorporating with SS. The SS was collected from IWK located at Senggarang and Perwira whilst clay soil was collected at Yong Peng, Johor. The characteristics of SS and clay soil were analyzed using X-ray fluorescence (XRF). From the results, it showed that SS was high with silicon oxide (SiO2) and zinc (Zn) that makes it compatible to replace clay soil as raw materials. Next, two types of sewage sludge brick (SSB) which are Senggarang brick (SB) and Perwira brick (PB) were incorporated with 0%, 1%, 5%, 10% and 20% of SS respectively. Then, the compressive strength test was conducted in accordance with the British Standard BS 3921: 1985. Based on the result, it shows that 5% of SS replacements as clay soil into fired clay brick have achieved the optimum strength. As for the indoor air quality (IAQ) test were done in walk-in stability chamber (WiSC) and the gas emission was compared with the Industry Code of Practice on Indoor Air Quality (ICOP-IAQ) through Department of Occupational Safety and Health Malaysia (DOSH, 2010). From the result, IAQ brick for SB and PB showed that up to 5% in fired clay brick were complied with the standard which below the acceptable limit that has provided for wall, column and cube formed. Thus, as a conclusion this method provided an alternative disposal method for the SS whilst producing a new low-cost building material with no negative effect to human as well as benefit to the environment.