Efficient Low-Cost Anaerobic Treatment of Wastewater Using Biochar and Woodchip Filters

Abstract

Access to improved sanitation is often lacking in many low-income countries, and approximately 90% of the sewage is discharged without treatment into receiving water bodies. The aim of this study was the development and evaluation of an efficient low-cost wastewater treatment system for developing countries. Biochar and woodchips, potential locally available and inexpensive materials, were used for anaerobic wastewater filtration and their suitability evaluated in comparison to gravel as a common reference material. Filters were fed with raw sewage from a municipal full-scale wastewater treatment plant in Germany at 22 • C room temperature with a hydraulic loading rate (HLR) of 0.05 m•h −1. This resulted in a mean organic loading rate (OLR) of 252 g COD •m −3 •d −1 and a mean organic surface load of 456 g COD •m −2 •d −1. To determine the influence of different filter materials, the removal efficiency of chemical oxygen demand (COD), total organic carbon (TOC), turbidity, and faecal indicator bacteria (FIB) E. coli and enterococci were tested. It was found that COD (up to 90%), TOC (up to 80%), FIB (up to 1.7 log 10-units), and turbidity (effluent turbidity below 35 NTU) could be significantly reduced. The findings of this study demonstrate the potential of anaerobic filters (AFs) for wastewater treatment in low-income countries to reduce water pollution and comprehensively improve water quality. The performance of biochar filters was significantly better over the entire experiment compared to woodchip and gravel filters with respect to COD, TOC, turbidity, and FIB removal, indicating the superior properties of biochar for wastewater treatment.

Slow sand filtration of raw wastewater using biochar as an alternative filtration media

“…Furthermore, as hydrolysis of organic substances is assumed to limit anaerobic degradation processes 41 , a lowering of OLR would lead to a reduced accumulation of organic matter. With an improved wastewater pre-treatment, such as pond systems or anaerobic filters to remove organic substances 9,42,43 , longer filter run times can be expected of AnBFs by preserving the relatively high HLR. This in turn may improve the formation of a well-developed biofilm in the filter bed, which is expected to increase the removal efficiency of pathogens and organic substances.…”

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“…The analysis of parameters was done using the procedure in the Standard Methods for the Examination of Water and Wastewater [12] to test the concentration of nutrients of interest namely nitrates, nitrites and phosphates from the effluent. The ultra violet and visible light spectrometer UV VIS (model 1800 Simdzu) from Sino-Africa-Joint-Research Center (SAJOREC) laboratories at JKUAT were used.…”

The Impact of Soil-Applied Biochars From Different Vegetal Feedstocks on Durum Wheat Plant Performance and Rhizospheric Bacterial Microbiota in Low Metal-Contaminated Soil

“…Both biochars were produced at a high pyrolysis temperature of 700 • C, as reported in Supplementary Table S1 in Supplementary Material S1 together with their other characteristics. These biochars are considered as standard; in fact, they have been widely investigated by several research teams (Wiedner et al, 2013;Kammann et al, 2015;Shen et al, 2017a,b;Kaetzl et al, 2018;Mašek et al, 2018; and several others) and were also used in this study for experimental reproducibility purposes.…”