Environmental and financial impact assessment of two plants of Amsterdam Water Supply

It is known that products, processes or services, may be environmentally orfinancially favourable during either the production, operation/use, or disposal stage,but unfavourable during another stage of the life cycle. This represents a complexchallenge to businesses: sound environmental performance along the life cycle of itsproducts, processes or services, without compromising quality, while keeping costs aslow as possible.Although it has already significantly reduced its environmental impacts in the pastyears - most notable by changing over the use of green energy yielding a reduction of27% - this is also now the challenge for Waterleidingbedrijf Amsterdam, whichproduces drinking water for households and industries. The company is in the processof renovating its pre-treatment plant in Loenderveen (LDV) and wants to use theopportunity to select a pre-treatment technology causing the least possibleenvironmental impacts in the most economical way.Based on the Life cycle Assessment approach, environmental impacts were assessedusing SimaPro 5.1 and the Eco-indicator 99 method. It was found that environmentalimpacts from drinking water production are 8.54 milli-ecopoints/m3• Further analysisdemonstrated that three parameters in the same number of unit processes were thedriving forces behind those impacts: the use of ferric chloride in coagulation, the useof NaOH in softening and the use of steam in the activation/regeneration of activatedcarbon, produced together 61% of the environmental impacts.Alternatives to reduce the impacts where assessed: i.e. the use of ferrous sulphate ascoagulant, the use of NaOH produced with green energy and increasing the run timeof the activated carbon, so as to reduce the use of oxidant. It was concluded thatenvironmental impacts can be potentially reduced by 37% with the alternativesproposed here provided that water quality is not affected.Financial impacts were assessed with Umberto 4.2 software, under an environmentalcost accounting approach based on materials and energy flows, and including otherdirect costs of production, like maintenance and direct labour costs. Softening, bioactivatedcarbon filtration (BACF) and coagulation are the three unit processes havingthe highest financial impacts. Energy use, purchase of NaOH and activated carbonpurchase and regeneration are the three parameters driving the financial impacts,contributing with 25%, 18% and 16% respectively.Softening, BACF and coagulation are the unit processes causing most of both theenvironmental and financial impacts. Nevertheless, those impacts are caused bydifferent parameters (for example, energy causes a negligible environmental impactbut the main financial impact), with the notable exception of NaOH, which causessignificant impacts in both environmental and financial terms.VI