Hydraid(TM) Biosand Water Filter Project

Characterization of the Biological Layer (Biofilm) of the Biosand Filter System

Water is essential to sustain daily life for all inhabitants of the world. Clean freshwater is a shrinking resource and has become a limiting commodity in large parts of the globe. Overuse, pollution, and contamination in underdeveloped countries has contributed to this dire issue. An inexpensive remedy is the potential for development and use of the Biosand filter in every household, as it delivers safe filtered potable water. Indeed, hundreds of HydrAid Biosand filters are in use the world over at present. However, where as the physical filtration of particulate impurities through graded sand is well understood, no scientific understanding of the role of the biofilm (presumably through an active food web), in ridding the water of pathogens and pollutants, exists. This study is designed to address this void by rigorously studying the structure and function (role) of the biofilm in the Biosand Filter system using modern microscopic and other analytical tools. Findings are expected to contribute to the basic scientific understanding of biofilm structure and function as well as establish a sound scientific basis for the operation of the Biosand filter system thereby enabling its widespread use in regions with questionable water quality and improving human health and welfare.

Key objectives for this study are:

  1. Study the structure (composition) and function (role) of the biofilm in the Biosand Filter system in the following manner:
    1. Employ traditional and possibly high resolution electron microscopy and fiber-optic microprobes to determine the community composition and development of the biofilm. (Q: What is the organization of the biofilm?)
    2. Determine the unique functionality, efficacy, and sustainability of the biofilm through respiration and DOC studies. (Q: What is going on?)
  2. Describe the phylogenetic composition of the biofilm using Fluorescence In Situ Hybridization (FISH) or other molecular ecological techniques. (Q: Who is there?)
  3. Describe the active components of the microbial food web within the biofilm. (Who is doing what?)
  4. Study Strategies:
    1. 1st Phase: Experiments in microcosms Fall 2010  Spring 2011.
    2. 2nd Phase: Testing in actual full-size Biosand Filters Spring/Summer 2011.

Relevant External Web Links:



Nicole with Mesocosm experiments

Nicole with Microcosm Experiments