A septic tank combined with a sand filter is the most common onsite wastewater treatment system worldwide, since it is a simple, lowcost and reliable treatment method. Alternatives to sand in filters could be advantageous in terms of availability of material and enhanced treatment properties. In this study, flow dynamics and pollutant transport in three filter materials; sand, pine bark and act...

The main focus of this paper is to describe a developed and dynamic method of designing finite impulse response filters with automatic, rapid and less computational complexity by an efficient Genetic approach. To obtain such efficiency, specific filter coefficient coding scheme has been studied and implemented. The algorithm generates a population of genomes that represents the filter coefficie...

A direct viable counting method was used to rapidly assess the effectiveness of chlorination of biofilms on rapid sand filter gravel. A total of 50% of the cells were nutrient responsive after exposure to 0.5 mg of chlorine per liter, while this value was 25% after exposure to 25 mg of chlorine per liter. A large variation was seen in the numbers of nutrient-responsive cells on different rocks....

In this paper, results ofa new sand filter design were presented. The drawer compacted sand filter (DCSF) is a modified design for a sand filter in which the sand layer is broken down into several layers, each of which is 10 cm high and placed in a movable drawer separated by a 10 cm space. A lab-scale DCSF was designed and operated for 330 days fed by synthetic grey water. The response of draw...