Content: It is acknowledged that conventional chrome tanning in leather processing discharges significant amounts of chromium, dissolved solids and chlorides. The recycling technology is one of the effective solutions to reduce the environmental impact of chrome tanning waste water at source. In this work, a novel closed recycling technology of chrome tanning wastewater was applied in the tanning process of the goat skins at a pilot scale level. The properties of chrome tanning liquors obtained by the recycling technology and the resultant crust were analyzed. The results show that this close recycling process works well. The contents of Cr2O3, total organic carbon, ammonia nitrogen and chloride ion in the waste water tend to accumulate with the increase of recycling times, and finally reach a balance after 5 times of recycling. The obtained leather sample is full, soft and having a shrinkage temperature comparable to that of conventional chrome tanned leather. SEM images indicate that the resulting leather samples by this recycling technology show fine and clean grain and well-dispersed fibrils. TG and DSC results show that the thermal stability of wet blue leathers tanned by the circular process are similar to those tanned by conventional chrome tanning process. Compared with conventional chrome tanning technology, water, salt and chrome tanning agent are saved in this process, and the zero emission of chrome tanning wastewater is realized. The cleaner production technology exhibits promising application prospect for its economic and environmental benefits. Take-Away: 1. A novel closed recycling technology of chrome tanning wastewater was applied in the tanning process of the goat skins at a pilot scale level. 2. The chrome tanning liquors obtained by the recycling technology and the resultant crust were analyzed. 3. Water, Sodium chloride and chrome tanning agent are saved by the closed recycling technology, and the zero emission of chrome tanning wastewater is realized.

This dissertation consists of two research projects in the area of Environmental Economics: water-recycling technology adoption and its cost-effectiveness in the U.S. horticulture industry (in Chapter 2), and urban tree cover's impact on residential location decision making in Milwaukee, WI (in Chapter 3). Chapter 2 evaluates the economic effects of labeling plants grown with water-recycling technology (WRT) practices in selected nursery operations in the Mid-Atlantic region of Virginia, Maryland and Pennsylvania. Partial budgeting, whole enterprise-level budgeting, sensitivity and break-even analyses are conducted to determine whether consumer premiums for plants grown with recycled water are sufficient to make WRT economically feasible combined with plant eco-labeling, and how such a labeling program would affect greenhouse/nursery production costs, gross revenues and net revenues. It is concluded that consumer premiums for plants grown with recycled water could offer nursery growers a method to improve their net returns while reducing pollution runoff and improving irrigation water usage efficiency. Chapter 3 focuses on non-market valuation of environmental (dis)amenities. Specifically, this chapter investigates the impact of urban tree cover on residential property location decision in the housing market of Milwaukee, WI. Residential sorting model embedded with "horizontal preference structure" is established to estimate the heterogeneous preferences for tree cover and other land cover attributes that vary by household socio-economic characteristics and then to identify the housing property owners' demand for these land cover attributes. The first part of this chapter mainly recovers the demand for "community trees" at the census block group level combined with 10 years property transaction data and neighborhood characteristics where the median income is aggregated to represent the household annual income. It is found that "community trees" are positively valued by the housing property owners and have a positive impact on housing price due to its positive externalities. Furthermore, income is found to be a strong exogenous demand shifter, leading to heterogeneous preference for the tree cover. The second part of Chapter 3 further investigates the impacts of both nearby trees and distant trees on residential property location decision using different spatial scales of land covers measurements. Instead of aggregating block group level median income, this study matches and merges disaggregated individual household annual incomes from the Home Mortgage Disclosure Act (HMDA) dataset to mitigate the potential aggregation bias. It is found that different spatial scales of land cover measurement result in varying willingness to pay estimates, implying that housing property owners have heterogeneous demands for nearby trees and distant trees. In other words, preferences for urban tree cover not only vary by household annual income, but also differ across spatial scales of the tree cover measurement. / Doctor of Philosophy / This dissertation contains two research projects related to researches on environmental economics. Chapter 2 talks about how adoption of water-recycling technology affects nursery growers’ finance (i.e., production cost, gross revenue, profit) and operation management in Mid-Atlantic region of Virginia, Maryland and Pennsylvania. It is found that consumers are willing to pay more money for horticultural plants produced with recycled water and these additional moneys would be sufficient for the growers to compensate the extra costs after adopting the water-recycling technology in the production. This study helps nursery growers and policy makers assess WRT adoption to improve crop water productivity and to reduce pollution of off-site surface waters. Chapter 3 discusses the impact of urban tree cover on housing price in the area of Milwaukee, WI. It is assumed that households with different socio-economic characteristics (e.g., household annual income) would have varying preferences for tree cover and other key characteristics when they make decisions on choosing their residential property locations. The first part of this chapter mainly focuses on “community trees”, namely the trees and forest within given census block groups. The second part of this chapter further takes nearby trees into consideration besides the distant trees so as to determine how trees on/near the residential properties affect the housing prices and whether the housing property owners prefer more trees on/near their properties. It is found that urban tree cover is valued by housing property owners and households with different income levels have diverse preferences for both nearby and distant trees. The research presented in this chapter not only makes academic contributions to the literatures of residential sorting model related to landscape (dis)amenities, but also facilitates the policy making of local governments and practitioners when it comes to urban and community trees and forestry programs.

Varje år uppkommer det stora volymer av jord- och bergmassor vid jord och schaktarbeten. Dessa massor måste hanteras, ofta körs de iväg till deponering och ersätts med nytt material. Det finns inga exakta siffror på hur stora massor det rör sig om. Men uppskattningsvis så kör var fjärde lastbil i Stockholms län omkring med jord- och bergmassor på sin last, detta är både kostsamt och resurskrävande. Förr fanns det upplag och täkter centralt, men i och med förtätningen av Stockholm flyttas dessa längre och längre bort från byggnationerna, med resultatet att transporterna blir dyrare, samtidigt som det sker en långsam utarmning av jord- och bergresurserna. Återvinning av jord- och bergmassorna skulle innebära att materialet inte behöver fraktas runt, och nytt material behöver inte tillverkas. Idag finns det ingen som äger frågan angående dessa massor och det finns ingen klar bild över aktörerna som är inblandade. Syftet med denna studie är att genom en aktörsanalys och kvalitativa intervjuer klargöra de olika aktörernas roller samt ta reda på deras attityd gällande återtvinningstekniker. Studien syftar även till att ta reda på var i en lärandeprocess som aktörerna befinner sig på. Resultatet visar att branschen inte har någon helhetssyn och att många aktörer har möjlighet att påverka flödet av jord- och bergmassor. Det visar också att attityden till att använda återvinningsteknik är positiv, men att ekonomiska intressen är styrande i frågan. I resultatet går även att se att det inte går att dra någon generell slutsats om var någonstans i en lärandeprocess som branschen befinner sig i, men att det saknas utbildning och att otydliga regelverk hämmar utvecklingen. / Every year there arise large volumes of soil and rock masses at ground and excavation work. These masses must be handled, often driven off to the landfill and is replaced with new material. There are no exact numbers on how big the masses are. But approximately every fourth truck in Stockholm County drive around with soil and rock masses on their load, this is both costly and resource intensive. There used to be stockpile and open-pit mining more central, but with the densification of Stockholm these are moved farther and farther away from the building sight, with the result that transportation becomes more expensive, while there is a slow depletion of soil and rock resources. Recycling of soil and rock masses would mean that the material does not need to be shipped around, and new material does not need to be manufactured. Today there is no question about who owns these masses and there is no clear picture of the actors involved. The purpose of this study is that through a stakeholder analysis and qualitative interviews to clarify the roles, as well as find out their attitude regarding recycling techniques. The study also aims to find out where in a learning process which the actors are. The result shows that the building and construction industry does not have a holistic approach and that many actors are able to influence the flow of soil and rock masses. It also shows that the attitude towards using recycling technology is positive, but that the economic interests of are the ruler in question. In the result can also be seen that it is impossible to draw a general conclusion about where in a learning process the industry can be find, but missing of education and unclear rules inhibits the development.