Assessment of the impact of water parameters on the flow rate of ceramic pot filters in a long-term experiment

Abstract

Poor water quality is a major contributing factor to disease in developing countries. Silver-coated ceramic pot filters (CPFs) are a relatively common form of household water treatment system (HWTS) representing an effective and sustainable technology for poor communities. Water production seems to be the major limiting factor of the CPF's lifetime and sustainability since low flow rates do not produce an adequate daily volume of treated water. This paper describes a long-term study of CPF flow rates under controlled conditions using three different water sources. The relationship between water characteristics and flow rate was assessed with the intent of identifying the principal parameters that impact CPF water production. The study concluded that turbidity seems to be the principal indicator in determining CPF lifetime in terms of quantity of treated water. There is no evidence that biological activity also contributes to premature failure of CPFs and the data did not indicate that chemical precipitation is responsible for the filter clogging. Manufacturers commonly conduct initial flow rate tests using clear water as a measure of quality assurance. However, the relationship between initial flow rate and average flow rate during the lifetime of the CPF should be further studied.

Household Production of Ceramic Water Filters in Western Rajasthan, India

“…5 as a function of the ambient temperature 53 . In the first hour, the fully filled filters produce an average of 600-950 ml of filtrate 54 .…”

High flow ceramic pot filters

“…Although ceramic pot filters are considered safe, robust and appropriate technologies, there is also a general consensus that water revenues are limited due to clogging of the ceramic element (Van Halem et al, 2007;Salvinelli and Elmore, 2015;Salvinelli et al, 2017). As part of the quality protocol, filters are tested at the factories for their flow rate, which should be within 1e5 L h À1 limits, depending on the factory (Rayner et al, 2013).…”

Preliminary Analysis of Water Production Rate and Turbidity in Source Water From Mount Merapi Using a Multi-Layer Sand Filter

“…A constant head flow rate test of all the filters used in the study was conducted in order to establish a baseline daily average. In order to maintain constant conditions and to maximize the flow rate of each filter over the time in which the experiment was conducted, constant head apparatuses similar to the one described by Salvinelli and Elmore [6] were used, as shown in Fig. 1.…”

“…A long-term investigation described by Salvinelli and Elmore [6] showed that flow rates decrease over time and that turbidity negatively affects both the average flow rate and the rate at which it decreases. Mihelcic et al [5] stated that turbidity has a negative impact on many water treatment processes in different ways, including clogging filters and therefore reducing their effectiveness.…”

“…Therefore cleaning the filtering unit provides a temporary benefit but does not prevent long-term clogging, and thus the flow rate is the limiting factor of the sand filtration lifetime and sustainability. According to Salvinelli and Elmore [6], turbidity seems to be the principal indicator in characterizing the sand filtration lifetime in terms of the water production capacity. In addition, the relationship between the sand filtration flow rate and turbidity is not well understood.…”