Due to several reasons, treatment methods for a certain waste are oftennot available locally in the waste handling and management industry. This is especially true for regions which are not densely populated. This requires transports, the majority of which consumes fossil fuel. To avoid this, local waste treatment methods need to be developed. In this work it is investigated how treatment of one hazardous waste is done; water and sludge containing oil. Based on sustainability criteria three novel methods are presented that can be conducted locally; mycoremediation, phytoremediation and electrocoagulation. The methods are evaluated in a case study of a recycling company. Mycoremediation and electrocoagulation were found to be suitable in the case study, as long as some criteria are fulfilled. In addition it is shown what barriers exist in law, policies and practices that hinder local treatment of water and sludge containing oil.

High rate algal ponds (HRAPs) are an advanced pond that provide efficient and cost-effective wastewater treatment, as well as the ability to recover nutrients in the form of microalgal biomass. Microalgal photosynthesis, nutrient uptake and subsequent growth, coupled with aerobic bacteria degradation of organic compounds, are fundamental to the process of wastewater treatment in HRAPs, yet are often limited in these ponds and, in particular, microalgal photosynthesis is well below the reported theoretical maximum. Understanding how the physico-chemical environment affects microalgal performance is therefore critical to improved wastewater treatment and nutrient recovery, yet has been the subject to few studies to date. This research focused on the enhancement of microalgal photo-physiology, growth and nutrient removal efficiency (NRE) through modification to the physical and chemical environment in wastewater HRAPs. In this study, I first examined the seasonal dynamics of microalgal performance in full-scale wastewater HRAPs. While both retention-time corrected chlorophyll biomass and photosynthetic potential increased from winter to summer, the summer-time performance was considered to be constrained, as indicated by the decreased light absorption, light conversion efficiency and NRE. The physico-chemical environment in the full-scale HRAPs were characterised by high day-time pH, high light attenuation and long, straight channels with low turbulence. This led to questions regarding 1) effects of nutrient supply, in particular carbon and 2) the role of the HRAP light climate on microalgal performance. I addressed these questions using a series of experiments that involved either changing the nutrient concentration and its supply or by modifying the light environment, through changes in pond operational parameters including CO2 addition, influent dilution, pond depth, hydraulic retention time (HRT), mixing speed and frequency. The overall results from these experiments showed that carbon was the primary and light the secondary limiting factors of microalgal performance. These limitations negatively affected light absorption, photosynthesis, productivity and NRE. While each operational parameter tested impacted on microalgal performance, to some degree, CO2 addition had the greatest influence on light absorption, photosynthetic efficiency and productivity, while continuous mixing had the greatest effect on NRE. Adding CO2 increased light absorption by 110% and 128%, maximum rate of photosynthesis by 185% and 218% and microalgal biovolume by between 150 – 256% and 260 – 660% (species specific), when cultures were maintained at pH 8 and 6.5, respectively. Providing sufficient mixing to achieve continuous turbulence enhanced NRE by between 300 – 425% (species specific), increased biomass concentrations between 150% and 4000% (species specific) compared to intermittent and no mixing, respectively, and increased harvest-ability of colonial species. However, at present, both CO2 addition and mechanical mixing attract high capital and operational costs. Modification to these technologies would be required to meet the objectives of cost-effective wastewater treatment and biofuel production. A more immediate and cost-effective solution demonstrated in this study was the altering pond depth, influent concentration and HRT. Doubling pond depth from 200 to 400 mm increased both microalgal nutrient removal and photosynthetic efficiencies which led to areal productivity increasing by up to 200%. When increased pond depth was coupled with decreased HRT, light absorption and photosynthetic performance further increased due to decreased internal self-shading and improved pond light climate. For nutrients, high influent loads increased productivity, while moderate loads increased effluent water quality. Overall, this work demonstrated that optimising the chemical and physical environment of wastewater treatment HRAPs (CO2 addition to maintain pH at 6.5 – 7, 400 mm pond depth, continuous mixing with vertical speed of 200 mm s-1, moderate nutrient load (15- 30 g m-3) and moderate HRT (4 / 6 days summer / autumn) can enhance microalgal biomass productivity, nutrient recovery as well as improve effluent water quality, particularly during summer when growth can be constrained.

The self-treatment system of nature cannot handle man-caused high rate water pollution on its own, therefore cleaning in wastewater treatment plant (WWTP) is necessary to avoid eutrophication – excessive enrichment of nature by nutrients. Current technologies applied in WWTPs are old, outdating and highly energy demanding, especially biological treatment step generally requires large amount of energy for aeration of water. The alternative to current system could be microalgae treatment step, which would use green algae to consume pollutants present in the waste water, namely nitrogen, phosphorus and heavy metals. Via photosynthesis it could produce oxygen required for biological oxidation of organic matter. Furthermore carbon source is necessary for microalgal growth, this can be added to the water as CO2 produced in other industries and so decrease global greenhouse gas footprint. Co-digestion of microalgae with undigested wastewater sludge under mesophilic conditions can give a synergic effect for biogas production, therefore harvested and co-digested microalgae could contribute to positive energy balance of WWTP. Full-scale microalgae cultivation in WWTP can be achieved only when good grow is guaranteed. This is a result of many factors, particularly access to nutrients, light condition, water temperature, and pH. The goal of master’s thesis was to understand and evaluate main factors influencing algal growth using literature review, propose design of microalgae treatment step with artificial lights and evaluate energy balance, of wastewater treatment plants in Uppsala and Västerås with new design. The work proposed two different designs of microalgae treatment steps, modelled in Excel and applied to current state of municipal WWTP in Västerås and Uppsala with belonging satellite plants. The first design of microalgae activated photobioreactor (MAASPBR) aimed to replace current biological treatment step. This is possible in Västerås and Uppsala WWTPs if microalgae can consume 75% of total nitrogen (Ntot) and produce at least 13.5 and 2.4 tonne O2/day in Västerås and Uppsala respectively. The sensitivity analysis showed that minimal volumetric algal yield of 0.15 kg/m3 ,day and 0.25 kg/m3 ,day is required for Västerås and Uppsala respectively, when oxygen production rate of 1.92 kg O2/kg microalgae is assumed. Furthermore harvested and co-digested algae with sewage sludge contributes to significant increase of biogas production and negligible transportation energy increase. The second design of open algal pond for reject water (OAPRW) aims to cultivate microalgae on reject water with high concentration of nutrients, generated in sludge centrifuge. The model assumed high algal growth due to excessive amount of nutrients and increased water temperature to 24°C. Results show a possible 23% and 20% electricity saving on blowers in the biological treatment in Västerås and Uppsala respectively. Both models have positive impact on energy balance in all WWTPs, however MAASPBR has greater uncertainties, because this type of photobioreactor has not been tested unlike OAPRW which has been tested in pilot plant scale.

Pharmaceuticals and personal care products (PPCPs) are detected routinely in raw and treated municipal wastewater. Conventional wastewater treatment processes are not effective in removing PPCP; therefore, treated wastewater discharges are one of the main entry points for PPCPs into the aquatic environment, and eventually into drinking water supplies. The use of laccase-catalyzed oxidation for removing low concentrations of PPCPs from municipal wastewater after primary treatment is investigated. Oxybenzone was selected as a representative PPCP. Like many other PPCPs, oxybenzone is not recognized directly by the laccase enzyme. Therefore, mediators were used to expand the oxidative range of laccase, and the efficacy of this laccase-mediator system in primary effluent was evaluated. Eight potential mediators were investigated. The greatest oxybenzone removal efficiencies were observed when 2,2’-azino-bis(3-ethylbenzthiazoline-6sulphonic acid) (ABTS), a synthetic mediator, and acetosyringone (ACE), a natural mediator, were present. An environmentally relevant concentration of oxybenzone (10 µg/L) in primary effluent was removed below the detection limit after two hours of treatment with ABTS, and 95% was removed after two hours of treatment with ACE. Several mediator/oxybenzone molar ratios were evaluated at two different initial oxybenzone concentrations. Higher mediator/oxybenzone molar ratios were required at the lower (environmentally relevant) oxybenzone concentrations, and ACE required higher molar ratios than ABTS to achieve comparable oxybenzone removal. The oxidation mechanisms and kinetics of the ACE mediator was evaluated. A better understanding of the mediator oxidation process would lead to a better design of the laccase-mediator system. An alternative laccase-mediator treatment configuration, which allows the enzyme and mediator to react prior to coming in contact with the target PPCP, was investigated. This treatment configuration shows promise for further development since it might reduce laccase and mediator requirements. Oxidation byproducts generated by the laccase-mediator system were characterized and compared to those generated during ozonation. Enzymatic treatment generated byproducts with higher mass to charge (m/z) ratios, likely due to oxidative coupling reactions. The results of this study suggest that, with further development, a laccase-mediator system has the potential to extend the treatment range of laccase to PPCPs not directly recognized by the enzyme, even in a primary effluent matrix. / text

Scenedesmus obliquus is a freshwater microalga which has high lipid content and biomass productivity. It is regarded as a promising species for production of biodiesel and other valuable organic compounds. Given the high cost of using potable water and commercial fertilizers, the use of municipal wastewater as algal growth medium is attractive in view of its constituent organic carbon and inorganic nutrients, including nitrogen and phosphorus. Investigating the mixotrophic cultivation of S. obliquus in an imitation municipal wastewater, the results of this study showed that: (1) The unmodified imitation wastewater by itself as expected yielded poor S. obliquus growth owing to its pH significantly decreasing to 3.5 as caused by the presence of Ammonium Chloride in the wastewater, inhibiting cell growth; (2) Adding either Acetic Acid or Sodium Acetate to the wastewater medium maintained its pH at 6.5 to 7.0, and its algae biomass on day 6 increased significantly by 212% and 194%, respectively; (3) Adding either Acetic Acid or Sodium Acetate to the wastewater medium maintained its pH at 6.5 to 7.0, and its algae biomass during exponential phase (day 4) significantly exceeded that in the MF control by 220.6% and 165.8%, respectively, while its algae biomass during saturation (day 6) significantly exceeded that in the MF control by 60.8% and 51.5%, respectively; and (4) Addition of NaNO₃ to the wastewater to match the level of N in the MF medium improved the algae biomass by 10%. This study developed ways for how the successful mixotrophic cultivation of S. obliquus in municipal wastewater could be achieved.

Ecological impacts of natural estrogens and xenoestrogens in treated wastewater include altered sexual development and sex ratios among continuously exposed organisms. The primary sources of estrogenic activity in wastewater are natural estrogens such as estrone, 17β-estradiol and estriol and synthetic compounds like 17α- ethinylestradiol, alkylphenols and alklphenol ethoxylates. Precursors in raw wastewater can yield estrogenic intermediates during wastewater treatment. All these compounds can be destroyed by biochemical processes conventional wastewater treatment processes, suggesting that conventional processes can be optimized for removal of estrogenic activity from wastewater. Sorption to sludges derived from wastewater treatment affects the fates of hydrophobic xenoestrogens such as nonylphenol, in part because the biodegradability of sorbed contaminants is limited. It may also be possible to tailor sludge stabilization processes to remove trace contaminants, including estrogens. For example, there are significant differences in the efficiencies of aerobic and anaerobic digestion for destruction of alkylphenols and probably other estrogenic compounds with aromatic moieties. Because advanced wastewater treatment is not economically feasible for most communities, there is ample incentive to develop accurate relationships between operational parameters and removal of estrogenic compounds during secondary wastewater treatment. Large quantities of polybrominated diphenyl ethers (PBDEs) have been used as flame retardants in clothing and plastic products since the 1970s. A small fraction of the PBDEs in manufactured products subsequently enters municipal wastewater. The resistance of these compounds to chemical and biochemical transformations provides opportunities for accumulation in sediments. Balances developed for PBDE congeners indicate that conventional wastewater treatment processes and soil infiltration of treated wastewater in recharge operations do not discriminate significantly among the major congeners in commercially available PBDE products. Accumulation of PBDEs at near part-per-million levels was measured in the sediments at the Sweetwater Recharge Facility in Tucson, Arizona, during 10-15 years of operation. Half times for loss of major PBDE congeners from sediments were decades or longer. Local agricultural soils amended with biosolids over a 20-year period showed similar accumulation of PBDEs. The widespread use of PBDEs in commercial products, compound persistence and toxicity indicate that additional effort is warranted to better understand fate-determining processes for PBDEs in the environment.

In this literature review the characteristics of two free-floating macrophytes, water hyacinth   (Eichhornia crassipes) and duckweed (Lemna sp.), and two microalgae, Chlorella and Scenedesmus, have been examined regarding their suitability as efficient nutrient removers in the treatment of wastewater with high levels of nutrients and suspended solids from a biogas plant in Loudden. The needs required for the plants to be able to grow in wastewater and the amounts of biomass they can produce have also been studied. The results show that Chlorella is capable of a very high uptake of nutrients in photobioreactors with high nutrient loadings. With an ammonia uptake maximum value at 10900mg/m2/d Chlorella outshines the other organisms in this study. The test organism that performed the closest to Chlorella in terms of nitrogen uptake was water hyacinth with an uptake about 1602mg/m2/d. One factor affecting nutrient uptake in a positive way is the growth rate. Free-floating macrophytes produce more biomass than algae do, and water hyacinth have been shown to be the most productive. It is important to conduct a regular harvest of the plants if a high production should be maintained. High quantity of biomass per unit area can inhibit the growth, and algae are more sensitive to this than the macrophytes often suffering from self-shading when the density is too high. The high level of nutrients in the wastewater prevents growth and dilution is required to achieve any growth at all. Therefore, conventional treatment methods might prove to be a better option.

Tiriant poveikį vandens ekosistemoms labai svarbu yra įvertinti ne tik nuotekų cheminius rodiklius, bet taip pat įvertinti kompleksinį toksinių medžiagų poveikį jautriems organizmams, kurie reprezentuotų tiriamai ekosistemai sukeliamą poveikį. Šiame darbe buvo atliktas Vilniaus miesto nuotekų kokybės tyrimas, nustatant nuotekų cheminę kokybę, bei toksiškumą vertinant sausumos ir vandens augalais, sėjamąja salota (Lactuca sativa L.), mažąja plūdena (Lemna minor L.) bei dafnijų (Daphnia magna) judrumo slopinimo testu. Darbo tikslas buvo palyginti skirtingų biotestų: sausumos augalų – sėjamosios salotos (Lactuca sativa L.) ir vandens augalų – mažosios plūdenos (Lemna minor L.) augimo slopinimo ir dafnijų (Daphnia magna) judrumo slopinimo testų jautrumą ir tinkamumą bendram nuotekų toksiškumui vertinti. Atlikus cheminę analizę gauta, kad nevalytose nuotekose pH= 7, NH4+ – 100 mg/l, NO2- – 0,03 mg/l, NO3- – 1 mg/l , PO4-3 – 18 mg/l, o nuotekose po išvalymo pH = 7,5, amonio koncentracija sumažėjo 10 kartų (NH4+ – 10 mg/l), nitritų koncentracija padidėjo 16,7 karto (NO2- - 0,5 mg/l), nitratų 20 kartų (NO3- –20 mg/l), o fosfatų koncentracija sumažėjo 30 kartų (PO4-3 – 0,6), tačiau nors ir amonio jonų koncentracija valytose nuotekose sumažėjo, ji viršijo nuotekoms taikomą DLK 1,5 karto. Atlikus sėjamosios salotos (Lactuca sativa L.) biotestavimą, nustatyta, kad šaknelės augimo slopinimas buvo jautriausias galutinis rodiklis. Mažosios plūdenos (Lemna minor L.) testas parodė, jog... [toliau žr. visą tekstą] / The examination of the impact on aquatic life is very important to evaluate not only the water chemical parameters, but also to assess a complex toxic effects on sensitive organisms that are representative of the investigated ecosystem effects. This work was carried out in Vilnius water quality test for chemical water quality and toxicity evaluation of terrestrial and aquatic plants, lettuce (Lactuca sativa L.), the duckweed (Lemna minor L.) and Daphnia (Daphnia magna) acute immobilisation tests. After physicochemical analysis revealed that untreated wastewater pH = 7, NH4+ – 100 mg/l, NO2- – 0.03 mg /l, NO3- – 1 mg /l, PO4-3 – 18 mg/l, and after treatment the effluent pH were 7.5, ammonium concentrations decreased by a factor of 10 (NH4+ – 10 mg /l), nitrite levels increased 16.7 times (NO2- – 0.5 mg / l), 20 times the nitrate (NO3- – 20 mg /l) and phosphate concentration decreased by 30 times (PO4-3 – 0.6), but while ammonium ion concentration in treated wastewater has decreased, it exceeded the limits applicable to discharges of 1.5. The lettuce (Lactuca sativa L.) bioassay showed that root growth inhibition was the most sensitive end point. Duckweed (Lemna minor L.) test showed that the most sensitive indicator was the mass of duckweed. Daphnia (Daphnia magna) mortality undiluted untreated wastewater after 48h was 100% and in treated wastewater – 40%. After a comparative study found that the main agent causing the effluent toxicity to Daphnia was ammonium. The... [to full text]

The objectives of this project are to rate three approaches for deriving effluent requirements; create a prioritized list of improvement steps; apply a watershed-level model to determine treatment plant requirements; and provide recommendations for deriving effluent requirements in Ontario. Results of a two-part stakeholder survey show that until advancements are made, compromise is necessary when selecting an approach for deriving effluent requirements, as no one approach meets all the evaluation criteria. However, the necessary steps toward improvement are relatively clear and require multi-disciplinary input. When the watershed-level modelling approach was applied, it was found that although there are challenges that must be addressed, overall, it appears advantageous to use a tool such as watershed-level models for the purpose of deriving effluent requirements in Ontario. / Natural Sciences and Engineering Research Council of Canada, Ontario Graduate Scholarship Program

This thesis is a participant observer case study that examined how three primary intervening variables (resources, trust, and risk communication) influenced the amplification and attenuation of perceived risk during a regulatory permitting process. The objective was to better understand the role of risk perception in a water policy decision, the issuance of a permit by the Texas Commission on Environmental Quality to the Waco Metropolitan Regional Sewerage System permitting them to discharge 1.5 million gallons of waste water effluent a day into Bull Hide Creek. The study took place between March 2008 and October 2009. The plant, designed to serve the sewer needs of distant cities, was planned without the participation of the residents of the creek community. After being notified of the permit application, they organized to protest the issuance of the permit which they felt presented a serious risk to their community. It is the conclusion of this researcher that risk perception played a key role delaying the issuance of the permit and construction of the plant. When perceived risk attenuated to a mutually acceptable level for all stakeholders, the permit was issued. It is postulated that if risk perception is recognized as a significant factor in potentially controversial urban and regional planning and policy decisions, implementation may be less difficult. The validity of this conclusion is constrained due to the fact this was a single case study and generalization is limited.