Centralised heavy metal recovery and removal synthesis for industrial wastewater
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Date
2017
Authors
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Publisher
Universiti Teknologi Malaysia
Abstract
One of the main pollutants in industrial wastewater is heavy metals that could originate from industries such as tanneries, semiconductors, dye, paper mills and textile. Heavy metal contaminated wastewater discharges are hazardous and can affect the health of living organisms. In most countries, the government has set a limit for heavy metal discharge to the river. Industries typically have to design their own decentralised heavy metal removal treatment plant (DHMRTP) to achieve this discharge limit which can be quite expensive, and requires operating and maintenance cost. Furthermore, since the heavy metals which are available in the wastewater is not much, industries tend to only remove the heavy metals and dispose it, instead of recovering it. These heavy metals are actually resources which can be recovered and sold. However, to recover heavy metals, economy of scale is needed. Due to this, this research aimed to develop a new concept of heavy metal recovery and removal treatment plant (CHRRTP). The idea was for the selected wastewaters polluted with heavy metals from different industries within an industrial region are sent to this CHRRTP plant. The industries will be charged certain amount of industrial charge based on the wastewater and pollutant amount. The cost should be lower than the price for them to build their own DHMRTP plant. The CHRRTP will gain profit from the industrial charges and also from selling the recovered heavy metals. The objectives of this research were: (1) To develop heavy metal recovery and removal synthesis for designing the most cost-effective and profitable centralised heavy metal recovery and removal treatment plant (CHRRTP) from a cluster of industrial wastewaters, (2) To validate the mathematical model programming with an illustrative case study involving an industrial zone to evaluate the performance of the CHRRTP, and (3) To perform a sensitivity analysis to ensure any changes in the industrial wastewater heavy metals concentration and flowrate, as well as other operating costs do not affect the profitability of the plant. The methodology was demonstrated by using a case study with 14 industries on-site. Based on the results, 13 of the industries’ wastewaters that were heavily contaminated with heavy metals were selected. The best heavy metal recovery and treatment technologies selected for this study were the molecular recognition technology and ceramic membrane system. The total profit for the system was 1,870,622 USD/yr with a payback period of five and half years.
Description
Thesis (PhD. (Chemical Engineering))
Keywords
Sewage—Purification—Heavy metals removal, Heavy metals, Sewage disposal plants