Pathogen removal during wastewater treatment by vermifiltration

Abstract

The study was designed to determine the effect of earthworms and the mechanism behind removal of pathogens during wastewater treatment by vermifiltration. The experimental phase continued for 10 weeks, starting after the initial stabilization phase of one week. Significant organic matter degradation and coliform removal were observed during vermifiltration of domestic wastewater. It was observed that vermifilter (VF) reduced biochemical oxygen demand and chemical oxygen demand by 84.8% and 73.9%, respectively. Significant log removal was observed for total coliforms (TC), faecal coliforms (FC), faecal streptococci (FS) and Escherichia coli with a mean log removal value (K) of 2.92, 2.20, 1.85 and 1.68, respectively. The decay rate constant (k) for indicator organisms (TC, FC and FS) was observed to be high as 8.04, 6.59 and 5.55 m day(-1), respectively. The population of total heterotrophic bacteria, total fungi and actinomycetes reduced remarkably by 3.14, 1.29 and 2.13 log units, respectively. Antibacterial activity of the isolated microorganisms from VF against gram-positive Staphylococcus aureus (ATCC 29213) and gram-negative E. coli (ATCC 25922) was observed which indicated the existence of a mechanism that may be responsible for pathogen removal during wastewater treatment. This demonstrated the production of antibacterial substance, from the microorganisms associated with earthworms, that causes inhibition of other microbes, specifying the effect of earthworms for pathogen removal. Overall, the present study contributes to the understanding of mechanism for pathogen removal during vermifiltration through antibacterial action of microflora.

Vermifiltration: Strategies and techniques to enhance the organic and nutrient removal performance from wastewater

“…Similarly, Kumar et al (2014) and Kumar et al (2016) have achieved an enormous removal of organics and nutrients, especially N, from the synthetic and real domestic wastewater, respectively, employing riverbed material as the vermibed material. Arora, Rajpal, Kumar, et al (2014) have also made the same conclusion. This could be because the riverbed material ensured adequate HRT of wastewater inside the vermibed and imparted higher adsorptive properties due to the presence of fine sand with enhanced SSA (Singh, D'Alessio, et al, 2021).…”

Performance evaluation of developed macrophyte-assisted vermifiltration system designed with varied macrophytes and earthworm species for domestic wastewater treatment

“…These indicators were used to evaluate the pathogenic quality of the treated effluents. The characteristics of wastewater, with particular reference to pathogen indicators were high and this could be due to the influx of human feces into the septic tank [ 2 ]. Large populations of the pathogen indicators grow in the intestinal tracts of humans and are excreted in faecal wastes.…”

“…In the tropical regions like Ghana, most of the domestic wastewater from households are collected and stored in septic tanks [ 1 ]. These wastewater are poorly treated and infiltrate the sub-surface to contaminate the groundwater table, contributing to freshwater depletion [ 2 ]. Contaminants in the wastewater such as organic and inorganic solids, nutrients as well as pathogens, have been reported to cause serious health effects [ 3 ].…”

Effect of Vermiaqua and Hospital wastewater on Bitter gourd (Momordica charantia L.)

“…There is no sludge formation takes place during vermifiltration of wastewater Thus, it is an eco-friendly system. Technically, vermifiltration is a synergistic and symbiotic activity of earthworms with microorganisms, here worms integrated with organic pollutants, present in wastewater and also increasing surface area which is suitable for the microbial activities and degradation also (Tomar et al,, 2011, Arora, et al,,2014and Samal, et al,, 2017.…”