Agrotechnology

Faecal Sludge Reuse in Agriculture: Challenges and Management Strategies

Freya Carrard^* Department of Sustainable Futures, University of Technology Sydney, Ultimo, Australia
^*Correspondence: Freya Carrard, Department of Sustainable Futures, University of Technology Sydney, Ultimo, Australia, Email:

Received: 03-Feb-2023, Manuscript No. AGT-23-20580; Editor assigned: 06-Feb-2023, Pre QC No. AGT-23-20580 (PQ); Reviewed: 20-Feb-2023, QC No. AGT-23-20580; Revised: 27-Feb-2023, Manuscript No. AGT-23-20580 (R); Published: 06-Mar-2023, DOI: 10.35248/2168-9881.23.12.305

Description

Faecal sludge (FS) is the semi-solid or liquid material that accumulates in on-site sanitation systems such as pit latrines and septic tanks. It contains a high amount of organic matter and nutrients that can be beneficial for soil fertility and crop production. However, it also harbours many pathogens that can pose serious health and environmental risks if not properly treated and disposed.

The reuse of FS in agriculture is a potential solution to address the challenges of FS management and resource recovery in lowand middle-income countries. It can reduce the pressure on landfills and wastewater treatment plants, improve soil quality and water retention, enhance crop yields and food security, and provide income opportunities for farmers and entrepreneurs. However, it also requires careful consideration of the technical, social, economic, institutional, and regulatory aspects to ensure its safety and sustainability. One of the key challenges of FS reuse in agriculture is the inactivation of faecal pathogens that can cause diseases such as diarrhoea, typhoid, cholera, hepatitis, and helminthic infections. These pathogens can be transmitted through direct contact with FS, ingestion of contaminated crops or water, or inhalation of aerosols. Therefore, FS needs to undergo adequate treatment before it can be applied to land or used as a fertilizer or soil conditioner.

There are various methods of FS treatment that can achieve different levels of pathogen reduction depending on the operating conditions, duration, and efficiency. Some of the common methods include

• Composting is a biological process that involves mixing FS with organic materials such as agricultural wastes or sawdust and allowing it to decompose under aerobic conditions. The high temperature generated by microbial activity can kill most pathogens within a few weeks or months. However, the composting process requires careful monitoring and control of parameters such as moisture content, carbon-to-nitrogen ratio, pH, oxygen supply, and turning frequency to ensure optimal performance and quality.

• Drying is a physical process that involves exposing FS to sunlight or artificial heat sources to reduce its moisture content and volume. The high temperature and low humidity can also inactivate most pathogens within a few days or hours. However, the drying process can be affected by weather conditions, drying area, FS characteristics, and potential odour and fly nuisances.

• Heat treatment is a thermal process that involves heating FS to a certain temperature for a certain time to destroy pathogens. The heat treatment can be achieved by using direct or indirect methods such as steam injection, boiling water, hot air, microwave, or solar concentrators. The heat treatment can achieve a high level of pathogen reduction within a short time but it also requires a high amount of energy input and equipment maintenance.

• Chemical treatment is a chemical process that involves adding substances such as lime, urea, ammonia, chlorine, or ash to FS to alter its pH, ammonia concentration, or oxidationreduction potential. The chemical treatment can inhibit or kill pathogens by disrupting their cell membranes, enzymes, or DNA. However, the chemical treatment can also affect the nutrient content and availability of FS and pose potential risks for human health and the environment if not properly handled and applied.

The choice of FS treatment method depends on various factors such as the availability of resources, the quality of FS, the intended use of FS products, the local regulations and standards, and the preferences and acceptance of stakeholders. Therefore, it is important to conduct a comprehensive assessment of the technical feasibility, economic viability, social acceptability, environmental sustainability, and health safety of each option before implementing it. The reuse of FS in agriculture can offer multiple benefits for sanitation service delivery and resource recovery but it also requires careful planning and management to ensure its safety and effectiveness. By applying appropriate treatment methods and following good practices such as hygienic handling, storage, transport, application, monitoring, and evaluation of FS products, it is possible to minimize the risks and maximize the opportunities of FS reuse in agriculture.