Performance of a stratified sand filter in removal of chemical oxygen demand, total suspended solids and ammonia nitrogen from high-strength wastewaters

Abstract

A stratified sand filter column, operated in recirculation mode and treating synthetic effluent resembling high-strength dairy wastewaters was studied over a 342-d duration. The aim of this paper was to examine the organic, total suspended solids (TSS) and nutrient removal rates of the sand filter, operated in recirculation mode, under incrementally increasing hydraulic and organic loading rates and to propose a field filter-sizing criterion. Best performance was obtained at a system hydraulic loading rate of 10 L m(-2) d(-1); a higher system hydraulic loading rate (of 13.4 L m(-2) d(-1)) caused surface ponding. The system hydraulic loading rate of 10 L m(-2) d(-1) gave a filter chemical oxygen demand (COD), TSS, and total kjeldahl nitrogen (TKN) loading rate of 14, 3.7, and 2.1 g m(-2) d(-1), respectively, and produced consistent COD and TSS removals of greater than 99%, and an effluent NO(3)-N concentration of 42 mg L(-1) (accounting for an 86% reduction in total nitrogen (Tot-N)). As the proportional surface area requirement for the sand filter described in this study is less than the recommended surface area requirement of a free-water surface (FWS) wetland treating an effluent of similar quality, it could provide an economic and sustainable alternative to conventional wetland treatment.

A Study on Mechanism of Organic Matter Removal in a Three-step Series Constructed Rapid Infiltration System Used for Domestic Wastewater Treatment

“…A correlation coefficient r of 0.97 was observed between the CoD removal percentages and the abundances of aerobic bacteria in the three-step series CRi system, indicating that the correlation was very obvious. This also indicated that microbes were playing a key role in the removal of organic matter, which was in agreement with some previous studies [10][11][12][13][14][15].…”

Removal of organic pollutants and nutrients from olive mill wastewater by a sand filter

“…4 shows an important reduction of the TSS as of the starting of filter operation (90%), this reduction remains always important until the clogging of the filter, and it varies between 75 and 90%. According to Healy et al (2007), significantly higher TSS removal (100%) was observed during the treatment of synthetic effluent resembling highstrength dairy wastewaters.…”

The use of laboratory sand, soil and crushed-glass filter columns for polishing domestic-strength synthetic wastewater that has undergone secondary treatment

“…Healy et al [12] found similar results when a laboratory sand filter was loaded with synthetic wastewater at TSS loading rates ranging from 5.2 to 12 g m -2 d -1 . In filters loaded with medium-to high-strength wastewaters, a biofilm layer forms as a schmutzedecke on the filter surface.…”

“…Intermittently loaded sand filters have also been successfully used to treat high-strength wastewater. [11,12] A novel horizontal flow biofilm reactor (HFBR) for treating wastewater, comprising a stack of about 40 horizontal polyvinyl chloride sheets, positioned over one another, has been developed by researchers at the National University of Ireland, Galway. [13] In this system, wastewater is intermittently pumped onto the top of the stack.…”