Recycling of Paper Mill Biosolids: A Review on Current Practices and Emerging Biorefinery Initiatives

Abstract

In a rapidly urbanizing global society, the issue of solid waste management has become even more challenging in recent times. Manufacturing of paper, an integral part of human civilization, generates a substantial amount of effluent sludge, which invariably needs extra monetary resources to dispose‐off in millions of tons annually around the world. Currently, most of the widely practiced disposal options, landfilling and incineration, invariably pose serious environmental risks to immediate neighborhoods as well as to society at large. Recent stricter environmental legislations and general public awareness have been forcing paper producers to follow a sustainable approach in dealing with residual biomass generated at their facilities. At the same time, reducing waste at source and recycling have become an integral part of waste management of some responsible companies and governments of the industrialized world have also taken a number of initiatives in this regard. This review presents a holistic overview on current practices in dealing with paper sludge and their environmental and economic implications. Also presented is a comprehensive discussion on emerging biorefinery trends leading to value‐added utilization of primary, secondary and mixed biosolids originating from effluent treatments plants, especially from paper mill operations.

Pulp and paper mill sludge management practices: What are the challenges to assess the impacts on greenhouse gas emissions?

“…PPMS management and disposal involve economic, environmental and social costs that will likely increase in the future. Some jurisdictions actually tend to reduce or ban landfilling of organic residuals by improving the efficiency of resource use and recycling (Council of the European Communities, 1991;US EPA, 1994;Ljunggren Söderman, 2003;EC-BiPRO, 2007;Fytili and Zabaniotou, 2008;Monte et al, 2009;MfE, 2010;MDDEP, 2011;Gouvernement du Québec, 2012), which will likely induce a change in the actual management practices (Mabee and Roy, 2003;Pervaiz and Sain, 2015). The actual greenhouse gas (GHG) emissions from the variety of PPMS management practices are unknown and should be addressed especially in the light of upcoming changes, consequence of reducing or banning landfilling.…”

“…The actual and common PPMS management practices are landfilling, land application for agricultural, silvicultural and reclamation purposes, and energy recovery through combustion (CANMET, 2005;Camberato et al, 2006;Gavrilescu, 2008;Likon and Trebše, 2012;MDDELCC, 2015;Pervaiz and Sain, 2015). The proportions of PPMS directed to one of these practices vary with time and jurisdiction policies.…”

“…The proportions of PPMS directed to one of these practices vary with time and jurisdiction policies. For instance, in the U.S., up to 87% of PPMS was landfilled in 1979 (Amberg, 1984) whereas this proportion has now decreased to 52% (Pervaiz and Sain, 2015). Nowadays in the province of Quebec, Canada, the annual production of 1.4 million tons of PPMS are managed at 29% by landfilling, 31% by land application, 35% by energy recovery and 5% by other practices (MDDELCC, 2015).…”

“…The Quebec's government policies aim to ban landfilling of PPMS by 2020 (MDDEP, 2011; Gouvernement du Québec, 2012) resulting in major challenges for the industry to change their PPMS management practices in order to meet the government objectives. The practice of landfilling will also tend to decrease in other jurisdictions following the application of such policies and pressure from the low public acceptance (Wang et al, 2008;Joo et al, 2015;Pervaiz and Sain, 2015). Depending on the local context for each paper mill, the tonnages actually directed to landfill sites may not be only manageable by current energy recovery installations and land availability.…”

“…Energy recovery through combustion benefits to pulp and paper industry (e.g., heat and electricity production) but it can be costly due to the implantation of combustion facilities and the prior PPMS dewatering process (CANMET, 2005;Mahmood and Elliott, 2006;Xu and Lancaster, 2008). Land application is generally feasible (Camberato et al, 2006;Pervaiz and Sain, 2015) and well accepted but this option can be practically and economically difficult for certain paper mills. For instance, some paper mills are located at great distances from agricultural lands, leading to high management costs and GHG emissions related to transport.…”