Evaluating sewage sludge contribution during co-composting using cause-evidence-impact analysis based on morphological characterization.

Pandiyan Balaganesh,Mangottiri Vasudevan,Narayanan Natarajan

doi:10.1007/s11356-022-19246-3

Pandiyan Balaganesh, Mangottiri Vasudevan + Show 1 more

Open Access

https://doi.org/10.1007/s11356-022-19246-3

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Abstract

The pertinent challenges associated with effective treatment of fecal sludge in medium scales necessitate alternative means for land application. The methods of compost preparation from sewage sludge and their modes of application to the agricultural fields have profound impacts on the soil ecology and environment. Besides the chemical conditioning effects on soil organic matter, they also impart physical attributes to the soil texture and structure. Though it is expected that compost addition improves water holding capacity and nutrient sequestration, there is lack of clarity in correlating the field outcomes with conditions of excess nutrient storage/leaching despite the agronomic benefits. In this study, we present a systematic cause-evidence-impact relationship on the feedstock composition, processing, and applications of co-composted sewage sludge. Various analytical tools were compared to elucidate the unique characteristics of co-composted sewage sludge to get a realistic understanding of the complex soil-compost interactions. Results from the spectroscopic characterization reveal the implications of selection of bulking agents and sludge pre-treatment in determining the final quality of the compost. Based on the results, we postulate a unique attribution of parent material influence to the formation of well-defined porous structures which influences the nutrient leaching/sequestrating behavior of the soil. Thus, the compounded impacts of composted organic matter on the soil and crop can be proactively determined in terms of elemental composition, functional groups, and stability indices. The present approach provides good scope for customizing the preparations and applications of aerobic microbial composts in order to derive the preferred field outputs.

Highlights

Global rate of sewage sludge generation from the wastewater treatment plants is rapidly increasing in recent years
The sewage sludge was collected from the in-house sewage treatment plant, vegetable wastes were collected from the hostel mess kitchen, while the agro waste such as dry leaves were collected from garden, and the sawdust was gathered from the carpentry workshop
The present study highlighted a coherent approach to evaluate the physico-chemical characteristics of sewage sludge-amended compost in order to evaluate the implications on its application, by using morphological analysis as a supporting technique

Summary

Introduction

Global rate of sewage sludge generation from the wastewater treatment plants is rapidly increasing in recent years. Co-composting is one of the sustainable approaches aimed at minimizing the burden of waste handling systems while providing numerous advantages for the agricultural sector (Liu et al 2006; Kong et al 2006; Singh et al 2020). Co-composting can be addressed as a sustainable management option for the sewage sludge by virtue of its circular economic approach, because it is simultaneously satisfying the nutrient requirements for the crop growth as well as minimizing the waste handling problems (Minamiyama et al 2008; Abbasi et al 2019; Ayesha 2020). From the agricultural point of view, the most implicating factors of compost amendment on the soil would be the soil moisture retention capacity, infiltration rate and nutrient sequestration effect (Adugna 2016; Abbasi et al 2019; Ai et al 2020). The recirculation of the leachate component during co-composting is found to provide added advantages such as maintaining the essential nutrients ratio and reducing the issues of seepage and foul odour (Chen et al 2020; Villamil et al 2020; Vasudevan et al 2019; Balaganesh et al 2020b)

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