Metals, which are generally more water soluble at lower pH, may become more mobile during this phase, leading to increasing metal concentrations in the leachate.Ĭountries including Germany, Austria, Sweden, Denmark, Belgium, the Netherlands, and Switzerland, have banned the disposal of untreated waste in landfills. The increase in the biomass of acidogenic bacteria increases the amount of degradation of the waste material and consuming nutrients. The H 2 generation phase is relatively short because it is complete by the end of the acid formation phase. High concentrations of VFAs increase both the biochemical oxygen demand (BOD) and VOA concentrations, which initiates H 2 production by fermentative bacteria, which stimulates the growth of H 2-oxidizing bacteria. Long-chain volatile organic acids (VOAs) are converted to acetic acid (C 2H 4O 2), CO 2, and hydrogen gas (H 2). During this phase, the decomposition intermediate compounds like the VFAs contribute much COD.
The increased organic acid content decreases the leachate pH from approximately 7.5 to 5.6. Hydrolysis of the biodegradable fraction of the solid waste begins in the acid formation phase, which leads to rapid accumulation of volatile fatty acids (VFAs) in the leachate. The use of 'rail-haul' permits landfills to be located at more remote sites, without the problems associated with many truck trips. In addition to trucks, some landfills may have equipment to handle railroad containers. The weighing process can assemble statistics on the daily incoming waste tonnage, which databases can retain for record keeping.
If necessary, they return to the weighbridge for re-weighing without their load. Before leaving the landfill boundaries, the waste collection vehicles may pass through a wheel-cleaning facility. After loads are deposited, compactors or bulldozers can spread and compact the waste on the working face. Afterward, the waste collection vehicles use the existing road network on their way to the tipping face or working front, where they unload their contents. During landfill operations, a scale or weighbridge may weigh waste collection vehicles on arrival and personnel may inspect loads for wastes that do not accord with the landfill's waste-acceptance criteria.
0 kommentar(er)
