Enteric bacteria in aerobically digested sludge

Fecal indicator and Ascaris removal from double pit latrine content

Since May 2006, the BRAC Water, Sanitation and Hygiene (WASH) Programme in Bangladesh has enabled more than 30 million people to achieve hygienic sanitation, contributing to an increase in sanitation coverage from 33 to 83% in programme areas and rapid progress towards universal access. In rural areas, most families have single pit latrines that need to be emptied when full. Since 2007, BRAC has promoted the use of hygienic double-pit latrines. Use of double-pit latrines, where appropriate, is also recommended in the Bangladeshi Draft National Water Supply and Sanitation Strategy. More than 800,000 double-pit latrines are in use in BRAC WASH areas, delaying the need for emptying and allowing time for the fecal matter to decompose while the resting pit is sealed. This paper focuses on a study undertaken by BRAC WASH to treat and safely use fecal material from double pit latrines as an organic fertilizer for rice and other crops. The study investigated the removal of pathogens from pit waste through simple solar drying and conducted analysis on nutrient properties of fecal sludge. The study showed a significant positive impact on developing organic fertilizer from fecal sludge.

Increased frequency of drug-resistant bacteria and fecal coliforms in an Indiana Creek adjacent to farmland amended with treated sludge

Many studies indicate the presence of human pathogens and drug-resistant bacteria in treated sewage sludge. Since one of the main methods of treated sewage disposal is by application to agricultural land, the presence of these organisms is of concern to human health. The goal of this study was to determine whether the frequency of drug-resistant and indicator bacteria in Sugar Creek, which is used for recreational purposes, was influenced by proximity to a farmland routinely amended with treated sludge (site E). Surface water from 3 sites along Sugar Creek (site E, 1 upstream site (site C) and 1 downstream site (site K)) were tested for the presence of ampicillin-resistant (AmpR) bacteria, fecal and total coliforms over a period of 40 d. Site E consistently had higher frequencies of AmpRbacteria and fecal coliforms compared with the other 2 sites. All of the tested AmpRisolates were resistant to at least 1 other antibiotic. However, no isolate was resistant to more than 4 classes of antimicrobials. These results suggest that surface runoff from the farmland is strongly correlated with higher incidence of AmpRand fecal coliforms at site E.Key words: drug-resistant bacteria, indicator bacteria, treated sludge, surface runoff.

Effect of lactic acid fermentation on bacterial pathogens and indicator organisms in broiler processing waste

Broiler processing offal (heads, viscera, and feet) was collected on 3 separate days from a commercial processing plant. Each sample was separately ground, supplemented with sucrose (6% initial concentration), inoculated with actively growing lactic acid bacteria (10(6) cfu/g of offal) from a commercial silage culture, and fermented at 37 C. Replicate samples were taken for standard microbiological analysis after 0, 48, and 120 h of fermentation. In fresh offal, heterotrophic plate count, total and fecal coliforms, fecal streptococci, and Aeromonas hydrophila concentrations were 7.4, 5.9, 5.9, 5.4, and 3.9 log10 cfu/g wet weight, respectively. After 48 h of fermentation, the bacterial concentrations were 7.6, 2.2, < 1.3, 5.5, and < 2.3 log10 cfu/g wet weight, respectively. After 120 h of fermentation, the bacterial concentrations were 6.9, < 1.1, < 1.1, < 1.1, and < 1.1 log10 cfu/g wet weight, respectively. Salmonella concentrations in fresh, 48-h fermented, and 120-h fermented offal samples were 3.7, < 1.5, and < 1.5 log10 most-probable-number/100 g wet weight, respectively. Lactic acid fermentation appears to be effective in reducing the number of bacterial pathogens and indicator organisms in poultry processing offal.

Detection of Salmonella enteritidis in environmental samples by monoclonal antibody-based ELISA

We have developed a enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody (ASCII) for the detection of Salmonella enteritidis in environmental samples. ELISA was used to test for sensitivity and specificity of ASCII. 38 other species of bacteria, including 31 Salmonella species were included in cross-reactivity testing with ELISA. ASCII showed no reactivity with any other species tested. ASCII was found to be an IgG1 specific for S. enteritidis lipopolysaccharide (LPS). The lower limits for S. enteritidis detection was 10(5) cells/ml for pure cultures and in 10% sludge (w/v). Environmental samples (raw wastewater, wastewater effluents, mixed liquor and aerobically digested sludge) were obtained twice from five sites and ELISA tested for the presence of S. enteritidis. ELISA results compared to the American Public Health Association (APHA) method of Salmonella detection were not significantly different (P greater than 0.05). The ELISA took 24 h for completion compared to 96-120 h for the APHA procedure. Results demonstrate the reliability of the ELISA and, more importantly, provides a rapid means of detection of S. enteritidis in environmental samples.