It is widely recognized that severe water pollution stems not only from improper waste disposal but also from the unregulated discharge of industrial and domestic wastewater. The direct release of untreated contaminated water constitutes a critical violation of environmental norms, necessitating urgent attention. Against this backdrop, zero liquid discharge (ZLD) has emerged as a pivotal concept in Water Quality Monitoring frameworks. This paper collaborates with manufacturers of Online Water Quality Monitoring Equipment to examine the core challenges impeding the implementation of ZLD.

1.High Investment and Operational Costs

The capital expenditure and ongoing operational costs associated with ZLD systems are prohibitively high, creating significant barriers to their large-scale promotion. In extreme cases, expenditures related to ZLD technology can account for up to 50% of the total investment in environmental protection projects, constraining its feasibility for many stakeholders.

2.Energy Intensity and Suboptimal Cost-Benefit Balance

Achieving ZLD requires substantial energy input, leading to an imbalance between performance and economic viability. As the concentration of solutes in wastewater increases, the saturation vapor pressure of the solution decreases, which slows the evaporation rate. Technologies such as steam-driven evaporation and crystallization—essential for ZLD realization—consume large volumes of electrical and thermal energy, often resulting in suboptimal outcomes for ZLD systems.

In summary, current technological limitations mean that complete zero wastewater discharge remains unachievable. However, compliant discharge of treated wastewater that meets pollution standards is technically feasible. Safeguarding water quality security must remain a non-negotiable priority, as it is fundamental to sustaining healthy living environments.