Turbidimeter, Spring 2011

Emily Clamp, Rohiverth Guarecuco, Julia Morris

Abstract:

The goal of the turbidity team was to create a low-cost turbidimeter that measures water turbidity within the range of 5 NTU to 250 NTU. Thus far, the team has brainstormed various turbidimeter designs and created several prototypes for simultaneously testing different LED display patterns. Many patterns have been assessed, including a dual-range LED display pattern for measuring a broad turbidity range. The dual-range LED pattern was tested using an experimental setup that allowed turbidity measurement of water that was constantly mixed with kaolin clay using a water pump. The team determined that only the fine pattern of the dual-range pattern was necessary, since the pattern alone could accurately measure turbidities from 5-200 NTU. This approach is based on resolution of the fine pattern within the turbidimeter as opposed to the use of contrast when using conventional Secchi disk patterns. The fine-resolution pattern was used to create a low-cost turbidimeter prototype equipped with an NTU scale based on the power-law equation derived from experimental results.

Turbidimeter, Fall 2011

Julia Morris, Andrew Gorodetsky, Heidi Rausch

Abstract:

This report will cover all the work that has been done by Cornell’s AguaClara program on turbidimeters. Research first started on creating a new, low cost turbidimeter at Cornell in the Spring of 2011. Since then several different prototypes have been created and ten turbidimeters have been sent to Honduras for use by communities who are considering building an AguaClara plant. The reason that a low cost turbidimeter needs to be developed is so that communities who may be in need of water treatment facilities can test their water without incurring the high expense of other turbidimeters currently on the market. The most current complete turbidimeter prototype can read NTU values down to 15 NTU. The research discussed in this report details new turbidimeter designs with which it may be possible to read NTU values down to approximately seven NTU. The most promising design includes the use of a blue LED light and a large HDPE block, which is used for diffusing the light. However, this design will need to be tested more thoroughly for accuracy before it can be fabricated for use in the field. In the future if research continues to be done to try to create a turbidimeter that can read turbidity values below 5 NTU the length of the lowering rod may have to be made longer than the current prototype, which is only 60 cm long. Without adding length to the lowering rod current research suggests that it may be impossible to read the turbidity of any water with an NTU value lower than seven.