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Measuring Runoff‐Suspended Solids Using an Improved Turbidometer Method
Author(s) -
Ginting Daniel,
Mamo Martha
Publication year - 2006
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2005.0219
Subject(s) - turbidity , distilled water , settling , chemistry , particle size , suspension (topology) , total suspended solids , particle size distribution , sucrose , suspended solids , particle (ecology) , surface runoff , soil science , chromatography , environmental science , environmental engineering , mathematics , wastewater , geology , food science , ecology , oceanography , chemical oxygen demand , homotopy , pure mathematics , biology
Differences in particle size distribution between runoff standards and unknown samples affect the accuracy of estimation of total suspended solids (TSS) concentration using the nephelometric turbidity (NTU) method. The objective was to quantify the effects of a sucrose solution as suspending medium and contrasting particle size distribution on nephelometric turbidity and accuracy of TSS estimation. Nineteen benchmark soils varying in texture and color were divided into particle size distribution of <250 and <2000 μm. Soils from these two aggregate classes were then made into suspension ranging from 0.2 to 15 g L −1 using distilled deionized water. Runoff suspensions ranging from 0.2 to 21 g L −1 were also collected from different watersheds. Turbidity of soil and runoff suspensions was measured in sucrose solution and in distilled deionized water. The sucrose solution density ranged from 1.10 to 1.30 kg L −1 Increasing sucrose solution density decreased turbidity. The TSS concentration was most sensitive to changes in turbidity with the 1.30 kg L −1 sucrose solution. Using the 1.30 kg L −1 sucrose solution, particle size bias and error of TSS estimates were decreased by at least 20% compared to distilled deionized water. Reduction in refraction index differences between the suspended particles and sucrose solution combined with reduced particle settling and reduced Brownian motion resulted in dampening the effects of particle size distribution. We propose a sucrose solution of 1.30 kg L −1 as a better suspending medium to dampen the effect of particle size distribution and thus improve suspension TSS concentration estimation.