Kristel Kroon

Step-wise temperature decreasing cultivates a biofilm with high nitrogen removal rates at 9°C in short-term anammox biofilm tests

ABSTRACT The anaerobic ammonium oxidation (anammox) and nitritation-anammox (deammonification) processes are widely used for N-rich wastewater treatment. When deammonification applications move towards low temperature applications (mainstream wastewater has low temperature), temperature effect has to be studied. In current research, in a deammonification moving bed biofilm reactor a maximum total nitrogen removal rate (TNRR) of 1.5 g N m−2 d−1 (0.6 kg N m−3 d−1) was achieved. Temperature was gradually lowered by 0.5°C per week, and a similar TNRR was sustained at 15°C during biofilm cultivation. Statistical analysis confirmed that a temperature decrease from 20°C down to 15° did not cause instabilities. Instead, TNRR rose and treatment efficiency remained stable at lower temperatures as well. Quantitative polymerase chain reaction analyses showed an increase in Candidatus Brocadia quantities from 5 × 103 to 1 × 107 anammox gene copies g−1 total suspended solids (TSS) despite temperature lowered to 15°C. Fluctuations in TNRR were rather related to changes in influent concentration. To study the short-term effect of temperature on the TNRR, a series of batch-scale experiments were performed which showed sufficient TNRRs even at 9–15°C (1.24–3.43 mg N g−1 TSS h−1, respectively) with anammox temperature constants (Q10) ranging 1.3–1.6. Experiments showed that a biofilm adapted to 15°C can perform N-removal most sufficiently at temperatures down to 9°C as compared with biofilm adapted to higher temperature. After biomass was adapted to 15°C, the decrease in TNRR in batch tests at 9°C was lower (15–20%) than that for biomass adapted to 17–18°C.

Nitrite inhibition and limitation – the effect of nitrite spiking on anammox biofilm, suspended and granular biomass

Anaerobic ammonium oxidation (anammox) has been studied extensively while no widely accepted optimum values for nitrite (both a substance and inhibitor) has been determined. In the current paper, nitrite spiking (abruptly increasing nitrite concentration in reactor over 20 mg NO-2-NL-1) effect on anammox process was studied on three systems: a moving bed biofilm reactor (MBBR), a sequencing batch reactor (SBR) and an upflow anaerobic sludge blanket (UASB). The inhibition thresholds and concentrations causing 50% of biomass activity decrease (IC50) were determined in batch tests. The results showed spiked biomass to be less susceptible to nitrite inhibition. Although the values of inhibition threshold and IC50 concentrations were similar for non-spiked biomass (81 and 98 mg NO-2-NL-1, respectively, for SBR), nitrite spiking increased IC50 considerably (83 and 240 mg NO-2-NL-1, respectively, for UASB). As the highest total nitrogen removal rate was also measured at the aforementioned thresholds, there is basis to suggest stronger limiting effect of nitrite on anammox process than previously reported. The quantitative polymerase chain reaction analysis showed similar number of anammox 16S rRNA copies in all reactors, with the lowest quantity in SBR and the highest in MBBR (3.98 × 108 and 1.04 × 109 copies g-1 TSS, respectively).

Nitric oxide for anammox recovery in a nitrite-inhibited deammonification system.

The anaerobic ammonium oxidation (anammox) process is widely used for N-rich wastewater treatment. In the current research the deammonification reactor in a reverse order (first anammox, then the nitrifying biofilm cultivation) was started up with a high maximum N removal rate (1.4 g N m−2 d−1) in a moving bed biofilm reactor. Cultivated biofilm total nitrogen removal rates were accelerated the most by anammox intermediate – nitric oxide (optimum 58 mg NO-N L−1) addition. Furthermore, NO was added in order to eliminate inhibition caused by nitrite concentrations (>50 mg ) increasing (2/1, respectively) along with a higher ratio of (0.6/1, respectively) than stoichiometrical for this optimal NO amount added during batch tests. Planctomycetales clone P4 sequences, which was the closest (98% and 99% similarity, respectively) relative to Candidatus Brocadia fulgida sequences quantities increase to 1 × 106 anammox gene copies g−1 total suspended solids to till day 650 were determined by quantitative polymerase chain reaction.

Nitritating-anammox biomass tolerant to high dissolved oxygen concentration and C/N ratio in treatment of yeast factory wastewater

Maintaining stability of low concentration (<1 g L−1) floccular biomass in the nitritation-anaerobic ammonium oxidation (anammox) process in the sequencing batch reactor (SBR) system for the treatment of high COD (>15,000 mg O2 L−1) to N (1680 mg N L−1) ratio real wastewater streams coming from the food industry is challenging. The anammox process was suitable for the treatment of yeast factory wastewater containing relatively high and abruptly increased organic C/N ratio and dissolved oxygen (DO) concentrations. Maximum specific total inorganic nitrogen (TIN) loading and removal rates applied were 600 and 280 mg N g−1 VSS d−1, respectively. Average TIN removal efficiency over the operation period of 270 days was 70%. Prior to simultaneous reduction of high organics (total organic carbon>600 mg L−1) and N concentrations>400 mg L−1, hydraulic retention time of 15 h and DO concentrations of 3.18 (±1.73) mg O2 L−1 were applied. Surprisingly, higher DO concentrations did not inhibit the anammox process efficiency demonstrating a wider application of cultivated anammox biomass. The SBR was fed rapidly over 5% of the cycle time at 50% volumetric exchange ratio. It maintained high free ammonia concentration, suppressing growth of nitrite-oxidizing bacteria. Partial least squares and response surface modelling revealed two periods of SBR operation and the SBR performances change at different periods with different total nitrogen (TN) loadings. Anammox activity tests showed yeast factory-specific organic N compound-betaine and inorganic N simultaneous biodegradation. Among other microorganisms determined by pyrosequencing, anammox microorganism (uncultured Planctomycetales bacterium clone P4) was determined by polymerase chain reaction also after applying high TN loading rates.

Start-up of low-temperature anammox in UASB from mesophilic yeast factory anaerobic tank inoculum

Robust start-up of the anaerobic ammonium oxidation (anammox) process from non-anammox-specific seeding material was achieved by using an inoculation with sludge-treating industrial -, organics- and N-rich yeast factory wastewater. N-rich reject water was treated at 20°C, which is significantly lower than optimum treatment temperature. Increasing the frequency of biomass fluidization (from 1–2 times per day to 4–5 times per day) through feeding the reactor with higher flow rate resulted in an improved total nitrogen removal rate (from 100 to 500 g m−3d−1) and increased anammox bacteria activity. As a result of polymerase chain reaction (PCR) tests, uncultured planctomycetes clone 07260064(4)-2-M13-_A01 (GenBank: JX852965) was identified from the biomass taken from the reactor. The presence of anammox bacteria after cultivation in the reactor was confirmed by quantitative PCR (qPCR); an increase in quantity up to ∼2×106 copies g VSS−1 during operation could be seen in qPCR. Statistical modelling of chemical parameters revealed the roles of several optimized parameters needed for a stable process.

Effect of concentration on anammox nitrogen removal rate in a moving bed biofilm reactor

Anammox biomass enriched in a moving bed biofilm reactor (MBBR) fed by actual sewage sludge reject water and synthetically added was used to study the total nitrogen (TN) removal rate of the anammox process depending on bicarbonate ( ) concentration. MBBR performance resulted in the maximum TN removal rate of 1100 g N m−3 d−1 when the optimum concentration (910 mg L−1) was used. The average reaction ratio of removal, production and removal were 1.18/0.20/1. When the concentration was increased to 1760 mg L−1 the TN removal rate diminished to 270 g N m−3 d−1. The process recovered from bicarbonate inhibition within 1 week. The batch tests performed with biomass taken from the MBBR showed that for the concentration of 615 mg L−1 the TN removal rate was 3.3 mg N L−1 h−1, whereas for both lower (120 mg L−1) and higher (5750 mg L−1) concentrations the TN removal rates were 2.3 (±0.15) and 1.6 (±0.12) mg N L−1 d−1, respectively. PCR and DGGE analyses resulted in the detection of uncultured Planctomycetales bacterium clone P4 and, surprisingly, low-oxygen-tolerant aerobic ammonia oxidizers. The ability of anammox bacteria for mixotrophy was established by diminished amounts of nitrate produced when comparing the experiments with an organic carbon source and an inorganic carbon source.

Deammonification process start-up after enrichment of anammox microorganisms from reject water in a moving-bed biofilm reactor

Deammonification via intermittent aeration in biofilm process for the treatment of sewage sludge digester supernatant (reject water) was started up using two opposite strategies. Two moving-bed biofilm reactors were operated for 2.5 years at 26 (±0.5)°C with spiked influent (and hence free ammonia (FA)) addition. In the first start-up strategy, an enrichment of anammox biomass was first established, followed by the development of nitrifying biomass in the system (R1). In contrast, the second strategy aimed at the enrichment of anammox organisms into a nitrifying biofilm (R2). The first strategy was most successful, reaching higher maximum total nitrogen (TN) removal rates over a shorter start-up period. For both reactors, increasing FA spiking frequency and increasing effluent concentrations of the anammox intermediate hydrazine correlated to decreasing aerobic nitrate production (nitritation). The bacterial consortium of aerobic and anaerobic ammonium oxidizing bacteria in the bioreactor was determined via denaturing gel gradient electrophoresis, polymerase chain reaction and pyrosequencing. In addition to a shorter start-up with a better TN removal rate, nitrite oxidizing bacteria (Nitrospira) were outcompeted by spiked ammonium feeding from R1.

SMOOTH TEMPERATURE DECREASING FOR NITROGEN REMOVAL IN COLD (9-15° C) ANAMMOX BIOFILM REACTOR TESTS

Domestic violence in itself is one of the most difficult, specific and wide-spread social-legal problems containing the number of signs of violation. Conflict directly concerns people connected with coexistence; it has the local, exclusive character and the fight against it is less effective in accordance with common practice of fight against the crime. Specificity of the fight against the crime of this category is expressed in both complexity of its revealing and in effective and lawful choice of coercive measures against it. The issue of domestic violence has been tabooed in many countries for a long time, because the disclosure of such issues was considered as interference in people’s private life. Although the society has gradually realized that the problem of domestic violence must not be ignored as violence endangers people’s health and life. Domestic violence is not only the problem of separate individuals, it has negative effect on the other members of the family, especially on minors and leads to distortion of their psyche and consciousness which, in its turn, leads to the formation of an unhealthy situation in the society.The author analyzes the results of the four stages of victimization surveys and Unified Crime Reports prepared by the Ministry of Internal Affairs of Georgia in 2010-2013. The results of victimization surveys and statistics reports related to indexes and structure of crime became important after the parliamentary elections held in October 1, 2012, resulted by defeating of the ruling political party “National Movement” which was in power for the last 9 years. The new coalition “Georgian Dream”, headed by the billionaire B. Ivanishvili, radically changed political climate and announced the acceleration of democratization of the country and adopted the legislation decriminalization policy. According the new policy, the government of the country carried out the general amnesty, and released more than 60% of all prisoners from the custody. Such policy became the object of serious criticism from the part of the oppositions and some experts. They have expressed concerns about the criminal situation and decreasing level of security in the country predicted anarchy and disorganizations. This article is an attempt to assess the real situation in Georgia and the level of real threat to stability posed by criminality.Everything has his pros and cons. Debtor’s rights and obligations during court order enforcement, causes of problems that may arise. This problem is in the whole country, not just in one city or in one social class. A very large number of families from everywhere around Georgia have been affected. How and where it started will be discussed below in the text. Rights of creditors and debtors overlap in many aspects. We need to be very careful when sorting out this issue. We cannot under any circumstances make a decision with a benefit of one party while the other party will suffer losses. Georgian law on “Law Enforcement” does not support in any ways rights of debtors and all the procedures highlighted are towards forcing the debtor to pay off the debt. At this stage based on the current law, current socio-economic problems, statistics, ways on sorting out the problem, this object of studies is very important and has a very high intrinsic value in its theoretical part as well as in its practical part. If the right approach is taken it is possible to minimise the need to protect rights of creditors or debtors in the futures, because every party will be fully aware of their abilities and punishments for failures to fulfil their obligations, before signing the contractThe article includes detailed employment and uniploymant analysis in each municipality. In the analysis we use results from household survey conducted by the National Statistics Service. More specific information about the labour market at the municipal level was collected through cooperation with local municipalities. For the analysis we used information from municipalities’ web pages, telephone conversations with stakeholders, personal meetings with experts and so on. It should also be noted that a certain part of the data obtained from municipalities and from administrative territorial units have an approximate nature, but based on these information it is possible to gain some valuable conclusions and make assumptions. Terms and reality of employment analysis is carried out not only at the level of the municipality but on the country and regional ones as well.This project aims to apply learning of operations research and optimizing resources to practical cases. The aim of this problem is to maximize the the fairness of the schedule , while respecting all the constraints . In regards with the results obtained after some tests ILP has found a very good solution to our problem . Better values of the penalties associated to the shifts could be defined in order to represent the reality more accurately especially by taking into account the length of the shifts. The models can also be solved by means of optimization software. As shown in this paper, the current schedules can benefit from this work. My problem is NP-hard that it means unsolvable.My objective is to do the objective values ( diff =0.1) . The ideal must be 0 but it is impossible.there is shown in the table in 5 shifts , 20 nurses 10 weeks. We see that when we increase the number of shift the objective value is decreasing. It is fact that when we add a shift the software must do more iterations but the penalty is decreasing. We see that with the same number of iterations the penalty is smaller when we add a shift.For the welfare of modern society and any state`s correct function it is very important to have straightened working court system and to ensure every person`s court accessibility. Each step of court case management is detailed in civil procedure code. The legislation of civil procedure of Georgia foresees some mechanisms and opportunities of the restriction of court accessibility, which must be studied. The meaning of this study is stipulated by huge importance of court accessibility itself and by need of due caution during its restricting. The access to the court right is reserved not only by national, but also by international law, as evidenced by Article 42 of the Constitution [1], ``The UN Convention for Protection of Human Rights and Fundamental Freedoms`` Article 6 [3]. As any study issue, this one also needs scientific, systemic approach. For fully demonstrating the issue it is advised to classify and define court accessibility restriction mechanisms. Here presented work is about this matter.The Administrative Law is a part of public law, as it is depended on the subordinate principle. It aims to realize public interest. On the other hand, Enforcement Law is part of administrative space, which regulates the rules and procedures of the enforcement process for different court’s decisions as well as other acts. As administrating effects our everyday lives, it is a public interest that this process should be kept in the legal borders. This is exactly what the Administrative Law is all about. It regulates the social relations in which were government and other administrative bodies play a major role. It is true that Enforcement Law provides us with the norms, rules and procedures of the legal administration, but it is still court’s responsibility to assess the legal quality of it. This is why we need effective justice, to have the competent court ruling practice and to enforce them properly.Collision issues are discussed in family law such as conditions of marriage, results of marriage, annulment of marriage, duty of maintenance, relations between parents and children, relations related to child’s origin, conditions of adopting, guardianship and tuition. I discuss issues of guardianship and tuition in mentioned work, which I think is very interesting and actual.