Experimental Studies on Continuous Electrocoagulation Treatment of Peat Water in Sarawak with Copper Electrodes

Abstract: Electrocoagulation is an electrochemical wastewater treatment method, which coagulates impurities particles and ions by using electrical current. In Sarawak, freshwater peat covers around 1.698 million hectares whereas the other 154,000 hectares are mangrove. Peat water is the water or moisture produced from these peatland or peat soil. Clean water availability in the rural coastal regions is limited due to the high financial cost of distribution of essential clean water resources to sparse population in the remote areas. Therefore, a cost-effective standalone electrocoagulation system for the treatment of peat water in Sarawak is one of the suggested solutions to this water supply problem. The main aim of this research is to develop a continuous electrocoagulation water treatment system by using copper electrodes to treat peat water in Sarawak. The peat water treated is targeted to achieve at least standard quality for domestic usage and the parameters studied to measure the optimal design of the treatment system are the turbidity, total suspended solids (TSS), total organic carbon (TOC), pH and chemical oxygen demand (COD) of the water treated. The experimental results meet the standard for Raw Water Quality and Drinking Water Quality with an optimum parameter of 20 electrodes, 0.7 cm inter electrodes spacing, current density of 5.99A/m2 and treatment time of 100 minutes. The total operating cost for the optimize parameters is RM 0.11 per litre of peat water. Overall, the treatment of peat water by using continuous electrocoagulation with copper electrodes is feasible. &nbsp

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data