Letter to the Editor

Phytosequestration of Carbon in Miscanthus × giganteus and Pinus sylvestris L. in Degraded Zinc Smelter and Post-Mining Soils

The main aim of these studies was to determine the potential for carbon sequestration in brown coal open-cast mine by phytoremediation using scots pine (Pinus sylvestris L.) and giant miscanthus (Miscanthus x giganteus) plants. This paper presents relationships between soil organic carbon (SOC) sequestration and carbon phytosequestration in waste dump associated with open-cast lignite mine in Central Poland. The research is the continuation of previously carried out experiments, but was conducted in field conditions. In reclamation of post-mining landscapes, during field experiment, an effect of sewage sludge, compost and lake chalk amendments and in combination of plants was investigated. The impact of soil amendments on carbon stock, CO₂ emission reduction, plant biomass production and carbon content in shoots and roots was studied. The highest SOC stock was found in soil treated with sewage sludge (33 Mg*ha⁻¹) and compost (45 Mg*ha⁻¹) stabilized by lake chalk. These fertilizer combinations also contributed the most in relation to CO₂ emission reduction through SOC stock (83 Mg*ha⁻¹ and 127 Mg*ha⁻¹ respectively). In addition, greater amounts (60–100%) of soil organic matter was converted into humic acids fraction. This phenomenon could be the initial stage of the progressive process of organic matter deposition and carbon sequestration in post-mining area. Carbon phytosequestration was determined through carbon bound in plant tissues. The highest carbon content (60%) in both plant species was recorded in treatments with sewage sludge and compost with lake chalk. Stabilization of compost by lake chalk application was good method to improve the efficiency of carbon sequestration in soil and carbon phytosequestration. Improving the efficiency of these two processes, through skillfully selected soil additives and plant species, may be used on a larger scale in the future as an alternative to the storage of carbon dioxide, especially in degraded areas.

This chapter investigates the issues of energy recovery using different kinds of sludge. It presents the findings of various studies regarding methane (CH₄) production from municipal sewage sludge (MSS), as well as comparing its characteristics and energy recovery potential with those of industrial sludge such as pulp and paper biosludge, tannery sludge (TnS), sludge originating from wastewater treatment facilities in the chemical, petrochemical and food processing industries. The main problems with anaerobic digestion (AD) of these kinds of sludge are also discussed in detail and addressed thoroughly by presenting methods of intensifying it by means of feed and substrate pretreatment, as well as the possibility of simultaneous treatment of these sludges with other organic waste in the process of anaerobic codigestion (AcD).