Application of wastewater treatment systems to minimize the water consumption of a pulp mill located in the Rio Doce basin (WatMin).

This research combined a technical approach with a social science approach to assess
the implementation of new technology in the pulp and paper industry. This industry is a huge
consumer of freshwater and energy resources, resulting in a large environmental footprint. Studies
show that reducing environmental impacts by increasing water and energy efficiency in the
pulp production process is paramount for companies in the industry to remain competitive and
sustainable (CORCELLI et al., 2018; DESHWAL; PANJAGARI; ALAM, 2019; GHOSAL,
2015; JOHAKIMU et al., 2016). The case of the Brazilian bleached kraft pulp mill in the Doce
River basin provided an opportunity to investigate the implementation of UF systems in practice,
which contributes to reduced water usage by permitting the reuse of process water (CHEN
et al., 2015). In this case, the need to reduce water usage was intensified by a mining disaster
that occurred in 2015. This disaster severely impacted the quality of the Doce River, the mill’s
main freshwater resource.
This research answered two main research questions. The first concerns the technical,
economic, and environmental benefits, risks, and impacts of implementing UF systems in three
different scenarios. The results show that UF implementation can greatly benefit the Brazilian
bleached kraft pulp mill by contributing to reduced freshwater intake and reduced COD, BOD,
TSS, and turbidity values. In Scenario 1, the principle benefits of the UF system are water savings
of 500 m3/h, higher energy efficiency in the recovery boiler, and 20% sludge reduction
from reduced color, COD and TSS concentrations. The options in Scenario 2 provide the opportunity
to profit from the recovery of pulp fibers, as well as several water re-use options that
also contribute to water savings of up to 500 m3/h. The options in Scenario 3 are the simplest
to implement with the lowest risks at the lowest costs, freeing up sand filters in the WTP for
Chapter 7. CONCLUSION CHAPTER 267
other uses and providing drinking water fit for human consumption. However, the third scenario
does not provide many other environmental or technical benefits. It is therefore recommended
to combine Scenario 3 with one of the options in Scenarios 1 and 2. The greatest water savings
can be achieved if both Scenarios 1 and 2a are implemented, however this has the highest
economic impact. Scenario 2b or 2c may be alternatively combined with Scenario 1 to balance
water savings and financial costs.
It is important to note that both Scenarios 1 and 2 may contribute to increased electrical
conductivity as well as calcium and potassium ion concentrations in the industrial water
stream. This may impact recovery boilers as well as other processes in the mill sensitive to these
changes. If the proper measures are taken, however, these risks appear low. Further modeling
may also be necessary to account for unknown chemical reactions, which are outside the scope
of this study. Reducing freshwater intake is an important goal for the pulp and paper industry,
as this reduces environmental impacts and increases production efficiency (GHOSAL, 2015;
TRAN; VAKKILAINNEN, 2016). Implementing UF in the Brazilian mill would contribute to
reduced freshwater intake as well as reduced COD, TSS, turbidity, and color concentrations
in the mill’s wastewater discharges. This can greatly benefit the recovery process of the Doce
River.
The second research question concerns the favorability of governance conditions in the
pulp and paper industry towards the implementation of new technology. Previous research suggests
that implementing new technology such as UF in the industry is difficult due to high
upfront costs and limited access to financial resources (ADNAN et al., 2010; MäNTTäRI et al.,
2010; SONG et al., 2015). However, increased pulp demand, the need to remain competitive,
and stricter environmental regulations place pressure on companies in the industry to increase
production efficiency (GHOSAL, 2015; KONG; HASANBEIGI; PRICE, 2016). Governance
assessment results suggest that the governance conditions surrounding the implementation of
new technology in the pulp and paper industry are favorable. Overall, there is significant support
from international governments, technology providers, and academia towards research, development,
and implementation. Meanwhile, companies are indeed motivated to implement new
technology in order to increase production efficiency and comply with government regulations
as well as social and environmental pressures. Governance assessment results also show that
companies in the industry are more likely to implement new technology if it has been previously
applied in other mills or in other industries. Thus, implementing UF in the Brazilian
mill could contribute to the application of UF in other mills, especially if the resources and
knowledge are readily available and accessible.
Notably, there is evidence that resources and motivations may be impacted by global
disasters, especially at the international level. Future studies may be therefore conducted to
assess the impact of global crises such as the Covid-19 pandemic on industrial technology implementation.
Additionally, future studies could monitor the quality of Doce River after UF has
been implemented in the Brazilian kraft pulp mill to further assess the environmental impacts.

Due to the existing pressure for a more rational use of the water, many public managers and industries have to re-think/adapt their processes towards a more circular approach. Such pressure is even more critical in the Rio Doce region, Minas Gerais, due to the large environmental accident occurred in 2015. Cenibra (pulp mill) is an example of such industries due to the fact that it is situated in the river basin and that it has a water demanding process. The current proposal is meant as an academic and engineering study to propose possible solutions to decrease the total water consumption of the mill and, thus, decrease the total stress on the Rio Doce basin. The work will be divided in three working packages, namely: (i) evaluation (modelling) of the mill process and water balance (ii) application and operation of a pilot scale wastewater treatment plant (iii) analysis of the impacts caused by the improvement of the process. The second work package will also be conducted (in parallel) with a lab scale setup in The Netherlands to allow fast adjustments and broaden evaluation of the setup/process performance. The actions will focus on reducing the mill total water consumption in 20%.