This document provides an executive summary of a final report for a project that evaluated using permeable concrete filters to provide clean drinking water in developing communities. The project aimed to design concrete filters that could remove contaminants like bacteria from water without needing treatment chemicals or power. Testing found the filters effectively removed over 99.9% of bacteria but resulted in high pH levels in the filtered water. The conclusions identified concerns with pH and concentrations of some chemicals to study further in a proposed Phase II. The overall goal of providing cleaner water sources aligns with sustainable development objectives.

1. NCER Assistance Agreement Final Report Executive Summary
Date of Final Report: April 6, 2007
EPA Agreement Number:
Project Title: Sustainable Concrete Filtration System for Developing Communities
Faculty Advisors: Dr. Stephan A. Durham and Dr. Anu Ramaswami,
Department: Civil Engineering
Institution: University of Colorado at Denver and Health Sciences Center
Student team member: Gregory M. Majersky, Civil Engineering
Project period: August 1, 2006 to July 31, 2007
Description
It was the goal of the study team to develop a system that can filter contaminated water;
thus producing safe drinking water for developing communities. The University of
Colorado at Denver and Health Sciences Center, UCDHSC, P3 team evaluated a non-
conventional filter material. Permeable or pervious concrete has traditionally been used
in producing pavement structures. Pervious concrete is a hardened mixture comprised of
water, cement, and gravel. The mixture has little to no sand. With the absence of sand,
voids are present to allow water to flow through the concrete structure. Our goal is to
design the shape, size, and effective gravel size to successfully filter contaminates from
non-potable water.
The research team chose concrete due to its wide use and availability throughout the
world. Global experience in working with this material is present and sufficient supply
and production infrastructure are already in place. No additional energy is required to
create systems to produce this traditional material.
Objective
The objectives of this research are:
To demonstrate that pervious concrete filters can be fabricated as regular concrete
but without fine grained materials. The ease and simplicity in fabrication of these
samples does not require special training and special fabrication materials.
To examine the pervious concrete filter effectiveness in improving overall water
quality for consumption or other uses.
To investigate the hypothesis that eliminating gravel larger than x inches is more
effective in bacteria and inorganic compound removal than an unsieved
composition of coarse grains when the filter dimensions were identical.
The overall goal is to provide people in developing communities, without any need for
electrical power, chemicals or expensive new technology and at minimal cost clean
drinking water. In addition, an existing technology, permeable concrete, is being
evaluated for a new potential use.

2. Summary of Findings
The first test performed was an erosion test. This was to examine how much, if any,
cementitious material or aggregate would be physically removed by the presence of
flowing water. Initially, the first three tests produced slightly turbid water with a small
amount of pebbles. As a result of this test, the research team began to flush the filter
with cold tap water for 70 minutes at a flow rate of 1 L/hr. Laboratory analysis of
samples taken from the erosion test was measured for metals concentrations and pH with
an Inductively Coupled Plasma (ICP) instrument. The erosion test samples were
analyzed for total recoverable metals, with the primary focus being iron, aluminum, and
magnesium. Three samples experienced higher than expected levels of magnesium.
Results showed that both iron and aluminum concentrations were within the
Environmental Protection Agency (EPA) secondary maximum concentration limits
(MCLs) for drinking water.
Bacterial testing was performed on filters with sieved and unsieved coarse aggregate.
These tests were conducted to provide a comparison of filter performance between the
unsieved vs. sieved filters. Pre-filtration and post-filtration dissolved oxygen (DO)
measurements were taken to measure oxygenation abilities of the unsieved and sieved
filters. The sieved filter produced an average of 0.21 mg/L increase in D.O. levels over
the unsieved filter. Percent removal of bacteria was calculated on a mg of bacteria/L
basis. The filter was successful in removing bacteria from a concentration of about 10^8
bacterial per mL of water to less than 1 per mL. The percentage of bacterial removal for
both filters was well in excess of the EPA primary MCLs for bacteria (99.9%).
The results of the metals analysis found that iron was removed to less than the minimum
detection level of the ICP in all but the third trial. The concentration of iron in both cases
was in excess of the EPA’s secondary drinking water standard of 0.3 mg/L. The
percentage of sodium removed by both filters increased similarly with each successive
trial.
Lastly, post-filtration pH was measured for each sample. The range of pH was 11.45 to
12.52. This level of pH is extremely high and is a concern regarding the filter’s
effectiveness. The pH level of filtered water will be further investigated in Phase II.
Conclusions
This study discusses a potentially new method of providing potable water to people in
developing communities without adequate drinking water. Concrete is a recyclable
material providing for both environmental and economical benefits. Infrastructure is
already in place around the world to produce concrete, thus little or no additional effort is
needed to produce pervious concrete filters.
The filter was determined to be effective in filtering bacterial; however, concentrations of
other chemical contaminants may increase in concentration. This was particularly
evident with the pH level of the filtered water. These concerns will be further
investigated in Phase II.

3. The unsuccessful factors of this experiment were an unexplainable increase in dissolved
copper concentrations (from 2 to 9 mg/L) and a very high pH (11 to 12). Further testing
will be conducted to evaluate copper concentrations and removal using this type of filter.
The impact of this project is the goal to provide cleaner water, which has an enormous
impact on the quality of life for all life on this planet. Phase I of this study focused on the
application of an original and innovative idea applied to an existing product, resulting in
a new use for pervious concrete.
Proposed Phase II Objectives and Strategies
Phase I of the pervious concrete filter study provided the P3 team with a prototype design
and preliminary filtration results. The proposed Phase II study will investigate the high
pH levels, low percent removal of copper, and high levels of magnesium in water quality
testing conducted in Phase I. In addition, the team will test additional contaminants not
included in the Phase I scope of work. The proposed study which includes the analysis
and modeling of permeable concrete filters for a developing community consists of five
tasks. These tasks include:
Task 1 – Travel to a developing community to understand the need, capabilities,
and resources needed to fabricate and install pervious filters for potable water
supply
Task 2 – Examine and fabricate additional pervious filters
Task 3 – Perform water quality testing on old and new filters
Task 4 – Model the “on-site” fabrication and installation of a filter in the
laboratory
Task 5 – Data analysis and development of pervious concrete filter guidelines
Supplemental Keywords: water, drinking water treatment, bacterial contamination,
disinfection, sustainable development, permeable concrete, pervious concrete