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Evaluation of physico-chemical pretreatment methods for landfill leachate prior to sewer dischargePoveda, Mario 10 April 2015 (has links)
The City of Winnipeg, MB currently hauls by truck the leachate from the landfill, to be co-treated with the municipal wastewater at a wastewater treatment plant. Pre-treating the leachate with physico-chemical methods would allow for direct discharge to the sewer system, avoiding transportation. The goal of this research is to evaluate the effectiveness of different pre-treatment options as well as their impact on a biological nutrient removal system.
In Phase I, the four pre-treatment options evaluated were air stripping, chemical coagulation, electro-coagulation and advanced oxidation with sodium ferrate. Chemical coagulation and air stripping reported the best COD and ammonia removal rates, respectively.
Phase II evaluated the effectiveness of the selected pre-treatment methods in the response of a biological treatment system. The pre-treatment was successful in allowing complete nitrification by lowering the influent ammonia concentration. However, if the ratio of leachate to wastewater is low enough; pre-treatment may not be needed as the dilution lowers the impact of the leachate’s higher concentrations.
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Effects of ozonation/filtration on the raw water from Lake Mälaren / Effekter av ozonering/filtrering på råvattnet från sjön MälarenLarsson, Nina January 2004 (has links)
<p>Syftet med examensarbetet var att undersöka effekterna av ozonering och filtrering på råvattnet från sjön Mälaren. Studien är utförd i en pilotanläggning på Lovö vattenverk, Stockholm Vatten AB, under våren 2004.</p><p>En negativ effekt med den konventionella reningen är den stora konsumtionen av kemiska koagulanter. Kemikalieanvändningen leder till många transporter och processen producerar också ett slam som för närvarande transporteras till Mälaren. År 2001 byggdes en pilotanläggning på Lovö vattenverk för utveckling av nya processer, en av processerna är ozonering följt av olika filter.</p><p>Ozonering har använts i Europa i många år som desinfektion i slutet av dricksvattenreningsprocessen. Intresset för ozonering har ökat markant sista åren och idag används ozonet också i andra steg i processen. Förutom desinfektion har ozonet andra fördelar, som oxidation av järn och magnesium, mikroflockning, reduktion av lukt och smak samt är bra på att reducera färgen på vattnet. Mikroflockningen leder till att kemikalieanvändningen kan minska och i vissa fall tas bort helt.</p><p>Den här studien startade med en litteraturundersökning följd av försök med ozonering och filtrering i pilotanläggningen. De första undersökningarna sammanfattades med att ozonering följt av filtrering inte gav tillräckligt bra resultat och processen behöver ett komplement för att producera ett högklassigt vatten.</p><p>Undersökningen fortsatte med laboratorieanalyser för att undersöka effekterna av olika kemiska koagulanter. Resultatet visade att järnsulfat tillsammans med kalcium var ett bra alternativ och en lägre kemikaliedos kunde användas.</p><p>Efter implementering av kalcium och järnsulfat till pilotanläggningen testades olika ozondoser och olika järnsulfatdoser. Det bästa resultatet erhölls då man använde sig av en ozondos på 6 mg O3/l och en järnsulfatdos på 50-60 μmol/l. Denna mängd av järnsulfat är ca 60 % lägre än den dos som används vid den konventionella reningen på Lovö vattenverk.</p><p>Olika filter används i pilotanläggningen och för att förbättra resultatet provades även ett Filtralite-filter som biofilter istället för GAC-filtret. Jämförelsen mellan Filtralite-filter och GAC-filter visade på stora skillnader i parametervärden i början av studietiden. När bakteriepopulationen ökade i Filtralite-filtret blev skillnaderna mindre och i slutet av undersökningstiden var parametervärdena likartade. Det slutliga resultatet indikerar att Filtralite-filter kan vara ett bra alternativ som biofilter.</p> / <p>This Master thesis was made to investigate the effects of ozonation and filtration on raw water from Lake Mälaren. The study was performed in lab-scale as well as in a pilot plant at Lovö waterworks, Stockholm Water Company during spring 2004.</p><p>The conventional treatment at Lovö waterworks comes with a few disadvantages, such as large consumption of chemical coagulants. The chemical consumption leads to many transports and the treatment also produces a sludge which is, in present, returned to Lake Mälaren. In 2001 a pilot plant were built at Lovö waterworks for research on new treatment processes, and ozonation followed by filtration is one of them.</p><p>Ozonation has been used in Europe for several years as disinfection at the end of the drinking water treatment process. The interests of ozonation has increased significantly in recent years and today the ozonation is used in other steps in the drinking water treatment process. Except for the disinfection, ozone has other benefits such as oxidation of iron and manganese, microflocculation, reduction of taste and odour and it is also effective to reduce the water colour. The microflocculation leads to the fact that less or no coagulants need to be used in the process.</p><p>This study started with a literature overview followed by experiments on ozonation and filtration in the pilot plant. After the first experiments the conclusions were that the ozonation and filtration did not reach the same results as Lovö waterworks. To continue, jar tests were made to see the effects of different coagulants. The result indicated that ferric sulphate together with calcium addition (pH-adjustment) was a good alternative. Thereby a lower coagulant dose could be used.</p><p>When ferric sulphate and calcium were implemented into the pilot plant, different ozone doses and ferric sulphate doses were tested. The best results occurred when an ozone dose of 6 mg O3/l and a ferric sulphate dose of 50-60 μmol/l were used. This amount of ferric sulphate is approximately 60 % lower than that for the conventional treatment at Lovö waterworks. To produce ozone electrons are needed and energy consumption increases with approximately 66 % compared to the conventional treatment. The decrease in chemical dose and increase in energy demand gives a decrease of the total cost with 10 % compared to the conventional treatment. The results indicate that the treatment with ozonation, calcium addition and ferric sulphate as a coagulant is an alternative to the conventional treatment.</p><p>Different filters were used in the pilot plant and to improve the results a Filtralite-filter was tested instead of the GAC-filter as a bio filter. When comparing Filtralite-filter with the GAC-filter there were large differences between the filters at the beginning of the study. When the bacteria population in the Filtralite-filter had started to increase the differences became less. In the end of the experimental period the filters had similar conditions and Filtralite-filter may be a good alternative as a biofilter.</p>
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Sustainable development of an integrated solid waste and wastewater treatmentWong, Ling Say January 2012 (has links)
This PhD thesis investigated solid and liquid waste treatment systems for Sureclean, a waste Management company based in the North of Scotland. Sureclean receives a diverse range of waste streams and the increasing need for sustainable development as well as stringent environmental legislation motivated this research to develop an integrated waste treatment system. Waste characterisation was conducted using a range of analytical instrumentation to identify the TPH, COD, heavy metals content, TOC, and particle size of Sureclean waste streams. From there, four treatment systems were investigated utilising Sureclean waste streams: mechanical separation, chemical treatment, electro-coagulation and the advanced oxidation process. Laboratory and field trials were conducted using these different treatment techniques and the analysis was performed to verify the treatment results. The result of these trials led to the development of four modular waste treatment units, that form the outcome of this research: the Sureclean Water Treatment System (SWTS), a filtration based mechanical separation system was shown to reduce the TSS, BOD and TOC content of an oily wastewater; the Sureclean Sludge Separation System (SSSTS), a chemical-enhanced filtration based system was demonstrated to reduce 52.6 % of the sewage sludge volume; the Sureclean Electro-coagulation Water Treatment System (SEWTS), a system that agglomerates colloid particles and demulsifies oil removed 99.9 % of TPH from Sureclean interceptor effluent; and the Sureclean Advanced Water Treatment System (SAWTS), an advanced oxidation process which was demonstrated to reduce the TPH of a contaminated groundwater collected from an ex-gas work. The treated effluent could be discharged to Sureclean interceptor. The four treatment units developed in this research expanded Sureclean waste treatment capabilities and an integrated system was developed to treat different waste streams and to improve the treatment efficiency thus increasing the revenue and future waste stream options for Sureclean.
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Effects of ozonation/filtration on the raw water from Lake Mälaren / Effekter av ozonering/filtrering på råvattnet från sjön MälarenLarsson, Nina January 2004 (has links)
Syftet med examensarbetet var att undersöka effekterna av ozonering och filtrering på råvattnet från sjön Mälaren. Studien är utförd i en pilotanläggning på Lovö vattenverk, Stockholm Vatten AB, under våren 2004. En negativ effekt med den konventionella reningen är den stora konsumtionen av kemiska koagulanter. Kemikalieanvändningen leder till många transporter och processen producerar också ett slam som för närvarande transporteras till Mälaren. År 2001 byggdes en pilotanläggning på Lovö vattenverk för utveckling av nya processer, en av processerna är ozonering följt av olika filter. Ozonering har använts i Europa i många år som desinfektion i slutet av dricksvattenreningsprocessen. Intresset för ozonering har ökat markant sista åren och idag används ozonet också i andra steg i processen. Förutom desinfektion har ozonet andra fördelar, som oxidation av järn och magnesium, mikroflockning, reduktion av lukt och smak samt är bra på att reducera färgen på vattnet. Mikroflockningen leder till att kemikalieanvändningen kan minska och i vissa fall tas bort helt. Den här studien startade med en litteraturundersökning följd av försök med ozonering och filtrering i pilotanläggningen. De första undersökningarna sammanfattades med att ozonering följt av filtrering inte gav tillräckligt bra resultat och processen behöver ett komplement för att producera ett högklassigt vatten. Undersökningen fortsatte med laboratorieanalyser för att undersöka effekterna av olika kemiska koagulanter. Resultatet visade att järnsulfat tillsammans med kalcium var ett bra alternativ och en lägre kemikaliedos kunde användas. Efter implementering av kalcium och järnsulfat till pilotanläggningen testades olika ozondoser och olika järnsulfatdoser. Det bästa resultatet erhölls då man använde sig av en ozondos på 6 mg O3/l och en järnsulfatdos på 50-60 μmol/l. Denna mängd av järnsulfat är ca 60 % lägre än den dos som används vid den konventionella reningen på Lovö vattenverk. Olika filter används i pilotanläggningen och för att förbättra resultatet provades även ett Filtralite-filter som biofilter istället för GAC-filtret. Jämförelsen mellan Filtralite-filter och GAC-filter visade på stora skillnader i parametervärden i början av studietiden. När bakteriepopulationen ökade i Filtralite-filtret blev skillnaderna mindre och i slutet av undersökningstiden var parametervärdena likartade. Det slutliga resultatet indikerar att Filtralite-filter kan vara ett bra alternativ som biofilter. / This Master thesis was made to investigate the effects of ozonation and filtration on raw water from Lake Mälaren. The study was performed in lab-scale as well as in a pilot plant at Lovö waterworks, Stockholm Water Company during spring 2004. The conventional treatment at Lovö waterworks comes with a few disadvantages, such as large consumption of chemical coagulants. The chemical consumption leads to many transports and the treatment also produces a sludge which is, in present, returned to Lake Mälaren. In 2001 a pilot plant were built at Lovö waterworks for research on new treatment processes, and ozonation followed by filtration is one of them. Ozonation has been used in Europe for several years as disinfection at the end of the drinking water treatment process. The interests of ozonation has increased significantly in recent years and today the ozonation is used in other steps in the drinking water treatment process. Except for the disinfection, ozone has other benefits such as oxidation of iron and manganese, microflocculation, reduction of taste and odour and it is also effective to reduce the water colour. The microflocculation leads to the fact that less or no coagulants need to be used in the process. This study started with a literature overview followed by experiments on ozonation and filtration in the pilot plant. After the first experiments the conclusions were that the ozonation and filtration did not reach the same results as Lovö waterworks. To continue, jar tests were made to see the effects of different coagulants. The result indicated that ferric sulphate together with calcium addition (pH-adjustment) was a good alternative. Thereby a lower coagulant dose could be used. When ferric sulphate and calcium were implemented into the pilot plant, different ozone doses and ferric sulphate doses were tested. The best results occurred when an ozone dose of 6 mg O3/l and a ferric sulphate dose of 50-60 μmol/l were used. This amount of ferric sulphate is approximately 60 % lower than that for the conventional treatment at Lovö waterworks. To produce ozone electrons are needed and energy consumption increases with approximately 66 % compared to the conventional treatment. The decrease in chemical dose and increase in energy demand gives a decrease of the total cost with 10 % compared to the conventional treatment. The results indicate that the treatment with ozonation, calcium addition and ferric sulphate as a coagulant is an alternative to the conventional treatment. Different filters were used in the pilot plant and to improve the results a Filtralite-filter was tested instead of the GAC-filter as a bio filter. When comparing Filtralite-filter with the GAC-filter there were large differences between the filters at the beginning of the study. When the bacteria population in the Filtralite-filter had started to increase the differences became less. In the end of the experimental period the filters had similar conditions and Filtralite-filter may be a good alternative as a biofilter.
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[en] APPLICATION OF THE ELECTROLYTIC PROCESS IN THE TREATMENT OF WASTEWATER FROM A PETROCHEMICAL INDUSTRY / [pt] APLICAÇÃO DO PROCESSO ELETROLÍTICO NO TRATAMENTO DE EFLUENTES DE UMA INDÚSTRIA PETROQUÍMICAANA CHRISTINA SOUZA WIMMER 06 May 2008 (has links)
[pt] A indústria petroquímica constitui um dos mais importantes
setores industriais no Brasil. A grande diversidade dos
processos de fabricação praticados faz aumentar a
necessidade de caracterização dos efluentes gerados
em cada planta industrial. Em geral, os efluentes
apresentam elevado teor de matéria orgânica, cuja remoção é
necessária para atender às normas técnicas
de descarte de efluentes industriais. Um dos processos de
tratamento utilizados é a coagulação química seguida de
tratamento biológico. Na coagulação química, sais de
alumínio ou ferro são usados como coagulantes. Devido às
grandes flutuações de carga orgânica, as quais dificultam a
dosagem do coagulante, buscam-se alternativas para
aprimorar o tratamento. Neste contexto, a eletrocoagulação
pode servir como alternativa à coagulação química ou como
pré-tratamento. O presente trabalho consistiu de ensaios de
coagulação química (Jar Test) e de eletrocoagulação em
escala de laboratório, utilizando efluentes gerados em uma
indústria petroquímica fabricante de borracha sintética. Os
ensaios permitiram comparar as eficiências de remoção de
matéria orgânica por eletrocoagulação e por coagulação
química, bem como comparar as eficiências
desses tratamentos em escala de laboratório com aquelas
obtidas na etapa de tratamento físico-químico (coagulação
química e floculação) da ETEI - Estação de Tratamento de
Efluentes Industriais da indústria citada. Em todos os
casos, as eficiências de remoção de carga orgânica foram
avaliadas pela DQO (Demanda Química de Oxigênio). Nos
ensaios de coagulação química em laboratório, utilizou-se
como coagulante o sulfato de alumínio. Os parâmetros
investigados foram o pH ótimo de coagulação e a dosagem
ótima de coagulante. Os ensaios do processo eletrolítico
foram realizados em batelada com eletrodos de alumínio. Os
parâmetros investigados foram a temperatura, o potencial
aplicado, o pH inicial, a distância entre eletrodos, o
número de eletrodos e o desgaste dos mesmos. As eficiências
de remoção de DQO pelo processo de eletrocoagulação
apresentaram valores até três vezes maiores que a média
mensal obtida na ETEI da indústria em questão, pelo
processo de coagulação química e floculação, no período da
coleta das amostras, indicando a possibilidade de aplicação
do tratamento eletrolítico ao efluente estudado. / [en] The petrochemical industry constitutes one of the most
important industrial sectors in Brazil. The great diversity
of processes of manufacture makes to increase the necessity
of characterization of the effluents generated in each
industrial plant. In general, the effluents presents high
grade of organic matter, whose removal is necessary to
expect to the technical standards of discarding of
industrials wastewaters. One of the used processes of
treatment is the chemical coagulation followed by
biological treatment. In chemical coagulation, aluminum
or iron salts are used as coagulants. Because of the large
fluctuations of organic load, which makes difficult the
dosage of the coagulant, alternatives are being
looked for the improvement of the treatment. In this
context, the electrocoagulation may be an alternative to
the chemical coagulation or can serve as a preliminar
treatment. The present work consisted of assays of
chemical coagulation (Jar Test) and of electrocoagulation
in scale of laboratory, using effluent generated in a
petrochemical industry manufacturer of synthetic
rubber. The assays had allowed to compare the efficiencies
of removal of organic matter by electrocoagulation and
chemical coagulation, as well as comparing the
efficiencies of these treatments in scale of laboratory
with those gotten in the stage of treatment physical-
chemical (chemical coagulation and flocculation) of
Industrial Effluent Treatment Station of the cited
industry. In all the cases, the efficiencies of organic
load removal had been evaluated by the COD (Chemical
Oxygen Demand). In the chemical coagulation experiments in
laboratory, the aluminum sulphate was used as coagulant.
The investigated parameters have been pH excellent of
coagulation and the excellent dosage of coagulant. The
assays of the electrolytic process had been carried through
in batch with aluminum electrodes. The investigated
parameters have been the temperature, the applied
potential, pH initial, the distance between electrodes, the
number of electrodes and the consuming of them. The
efficiencies of COD removal for the electrocoagulation
process reached values up to three times higher that the
monthly average observed in the treatment station of the
studied industry in the chemical coagulation and
flocculation stage. The results indicate the possibility of
application of the process in the treatment of the studied
effluent.
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Aplicação da técnica de eletrofloculação utilizando corrente alternada de frequência variável no tratamento de água de produção da indústria do petróleo / Variable frequency AC current aplied to the treatment of produced waters from the oil industryAlexandre Andrade Cerqueira 07 January 2011 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / O principal objetivo da tese está relacionado ao tratamento de águas oleosas
através da eletrofloculação utilizando corrente alternada de frequência variável, o
qual procurou explorar as potencialidades desta técnica. Com a crescente demanda
por petróleo e seus derivados, é cada vez maior a produção dessas águas
residuárias que, antes de serem descartadas, precisam ser submetidas a tratamento
que satisfaçam aos requisitos legais. O trabalho apresentado descreve o
levantamento bibliográfico e os resultados dos ensaios realizados, empregando o
tratamento de eletrofloculação com a finalidade de remover as substâncias
consideradas poluentes presentes nestes efluentes. O processo de eletrofloculação
foi testado tanto para o tratamento em corrente continua quanto em corrente
alternada de frequência variável em efluentes sintéticos e reais de alta salinidade,
contendo teores elevados de óleos e graxas, turbidez e cor. Eficiências de redução
de 99% para óleos e graxas, cor e turbidez foram obtidos utilizando eletrodos de
alumínio. O processo de eletrofloculação demonstrou-se bastante vantajoso em
função da alta condutividade que permite o tratamento com menor consumo
energético. A tecnologia de eletrofloculação com corrente alternada quando
comparada com a tecnologia de corrente contínua se mostrou muito eficiente em
relação a economia no desgaste de massa de eletrodos, o que, dependendo do
tempo de aplicação da corrente elétrica nas mesmas condições de estudo, houve
redução de mais da metade do consumo. / The main aim of the present work was to study the treatment of oil
wastewaters using electroflocculation with AC and variable frequency and to explore
the potentiality of the process. With the increasing demand for oil and its derivatives
the production of oil wastewaters also increases. Before its final disposal, these
undesirable wastewaters must undergo treatment to adjust its quality to legal
requirements. The present work presents an extensive literature survey and the
experimental results obtained can be deemed as excelent, as reduction efficiencies
of about 99% of the main quality parameters, namely, oils and greases, turbidity and
colour, were obtained. The process was carried out using both direct and variable
frequency alternate currents in high salinity samples of both real and synthetic
wastewater. containing high levels of oil and grease, turbidity and color. Reduction
efficiencies of 99% for oils and greases, color and turbidity were obtained using
aluminum electrodes. The process electroflocculation seem to be quite
advantageous due to the the fact that high conductivity values result in considerably
low energy consumption. Electroflocculation processes using AC , as compared with
similar processes, proved to very efficient, mainly because of its potential economy in
mass of electrodes, which, depending on the time of application of electric current in
the same conditions of study, a reduction of more half the consumption was
obtained.
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Aplicação da técnica de eletrofloculação utilizando corrente alternada de frequência variável no tratamento de água de produção da indústria do petróleo / Variable frequency AC current aplied to the treatment of produced waters from the oil industryAlexandre Andrade Cerqueira 07 January 2011 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / O principal objetivo da tese está relacionado ao tratamento de águas oleosas
através da eletrofloculação utilizando corrente alternada de frequência variável, o
qual procurou explorar as potencialidades desta técnica. Com a crescente demanda
por petróleo e seus derivados, é cada vez maior a produção dessas águas
residuárias que, antes de serem descartadas, precisam ser submetidas a tratamento
que satisfaçam aos requisitos legais. O trabalho apresentado descreve o
levantamento bibliográfico e os resultados dos ensaios realizados, empregando o
tratamento de eletrofloculação com a finalidade de remover as substâncias
consideradas poluentes presentes nestes efluentes. O processo de eletrofloculação
foi testado tanto para o tratamento em corrente continua quanto em corrente
alternada de frequência variável em efluentes sintéticos e reais de alta salinidade,
contendo teores elevados de óleos e graxas, turbidez e cor. Eficiências de redução
de 99% para óleos e graxas, cor e turbidez foram obtidos utilizando eletrodos de
alumínio. O processo de eletrofloculação demonstrou-se bastante vantajoso em
função da alta condutividade que permite o tratamento com menor consumo
energético. A tecnologia de eletrofloculação com corrente alternada quando
comparada com a tecnologia de corrente contínua se mostrou muito eficiente em
relação a economia no desgaste de massa de eletrodos, o que, dependendo do
tempo de aplicação da corrente elétrica nas mesmas condições de estudo, houve
redução de mais da metade do consumo. / The main aim of the present work was to study the treatment of oil
wastewaters using electroflocculation with AC and variable frequency and to explore
the potentiality of the process. With the increasing demand for oil and its derivatives
the production of oil wastewaters also increases. Before its final disposal, these
undesirable wastewaters must undergo treatment to adjust its quality to legal
requirements. The present work presents an extensive literature survey and the
experimental results obtained can be deemed as excelent, as reduction efficiencies
of about 99% of the main quality parameters, namely, oils and greases, turbidity and
colour, were obtained. The process was carried out using both direct and variable
frequency alternate currents in high salinity samples of both real and synthetic
wastewater. containing high levels of oil and grease, turbidity and color. Reduction
efficiencies of 99% for oils and greases, color and turbidity were obtained using
aluminum electrodes. The process electroflocculation seem to be quite
advantageous due to the the fact that high conductivity values result in considerably
low energy consumption. Electroflocculation processes using AC , as compared with
similar processes, proved to very efficient, mainly because of its potential economy in
mass of electrodes, which, depending on the time of application of electric current in
the same conditions of study, a reduction of more half the consumption was
obtained.
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Comparative Life Cycle Assessment of Sludge Treatment Systems : Is recycling aluminium based coagulant from chemical sludge the way of the future? / Jämförande livscykelanalys av slamhanteringssystem : Är återvinning av aluminiumbaserad koagulant från kemslam framtidsvägen?Henriksson, Patrick January 2017 (has links)
Chemical coagulation is a widely used wastewater treatment method around the world to reduce impurities from the process water in various industries. However, the large amounts of coagulation chemicals that are required for the removal of dissolved particles create a chemical sludge which poses a great environmental problem. Purac AB, a Swedish wastewater treatment company attempts to solve this problem with a new technology called the ReAl process. The ReAl process can recycle the aluminium ions from the commonly used coagulant aluminium sulfate, which reduces the amount of chemical sludge and the amount of aluminium sulfate needed in the coagulation process. In this study, a comparative life cycle assessment was conducted with a cradle-to-grave approach and mostly in accordance with the ISO-14040 series with the only deviation of not including resource-based impact categories. The goal was to evaluate the environmental impact of two sludge treatment systems – a conventional system (system 1) and a system which includes the ReAl process (system 2). Furthermore, the environmental performance of two dewatering equipment’s, a decanter centrifuge and a filter press, were examined in system 1, while in system 2, the exclusion of sludge drying was investigated. The scope of the study did not include the infrastructure of the sludge treatment systems and the ReAl process since previous studies have shown that, the environmental impact from the infrastructure in the wastewater treatment industry is relatively small compared to other factors, such as the energy and coagulation chemical used in these systems. The characterization results showed that system 2 had the lowest environmental impact on all the evaluated impact categories. The results also revealed that system 1 would have a slightly lower environmental impact if the chemical sludge was dewatered with a decanter centrifuge instead of a filter press. Similarly, system 2 would have a slightly lower environmental impact if sludge drying was excluded from the system. However, the environmental performance gain from selecting the best dewatering and drying equipment is limited and considered within the margin of error. Thus, this thesis suggests selecting the sludge treatment equipment based on their economic and technical factors before their environmental performance. The largest environmental impact in system 1 derived from the use of the coagulation chemical aluminium sulfate, while in system 2, sulfuric acid used in the ReAl process contributed the most to its environmental impact. The sensitivity analysis showed that a “clean” electricity mix is essential for system 2 and the ReAl process overall impact on the environment compared to system 1.
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