The Department of Environment and Natural Resources (DENR) has set the guidelines on the use of waste materials to promote the utilization of alternative fuels and raw materials in the production of cement. DENR Secretary Horacio Ramos cited that cement production is energy-intensive and is already being tapped by giant cement companies in the country to co-process alternative fuels and alternative raw materials in manufacturing cement.

Alternative fuels refer to non-traditional fuels, such as waste materials, that provide thermal energy in the production of cement, while alternative raw materials refer to waste materials that provide minerals essential in the production of cement. Meanwhile, co-processing is the reuse or recovery of mineral or energy content of waste materials while simultaneously manufacturing cement in a single combined operation. Ramos has signed DENR Administrative Order No. 2010-06 to provide guidelines to ensure that the use of alternative fuels and raw materials in the cement industry is compatible with existing national laws and policies on hazardous waste, waste management and air quality standards to reduce their environmental impacts.

The DENR guidelines include the registration and permitting requirements and the standards and procedures in co-processing of waste materials in cement production. Ramos noted that waste materials, which can be used in cement kiln burners, include plastic waste, car tires, waste wood, rice husk, sewage sludge, animal meal, waste oil and solvents. As for hazardous waste materials, Ramos said these should pass the acceptance criteria set by the Department based on their calorific value, mineral oxides, heavy metal content and other substances and impacts on kiln operation, clinker and cement quality.

Based on the DENR AO, an alternative raw material is acceptable if its ash content is greater than 50 percent, and its total mineral oxide content is greater than 75 percent. An alternative fuel should have a gross calorific content of not less than 2,000kcal/kg. The DENR chief said the waste materials may be allowed to undergo pre-processing to comply with the requirement. Should they still fail to pass the waste acceptance criteria, these shall be banned from being used as alternative fuels.

The order also prohibits the use of health care wastes, asbestos-containing wastes, all types of batteries, electronic assemblies and scraps, explosives, cyanide wastes, mineral acids, radioactive wastes and un-segregated municipal solid wastes as alternative fuels. Cement kilns are fuelled traditionally by non-renewable energy, such as coal, fuel oil, pet-coke and natural gas. Traditional raw materials used in cement production, on the other hand, include limestone, marl, sand, shale, clay, pyrite cinder, diorite, silica, to name a few.