Natural Compost Research Articles

Housefly maggot-treated composting as sustainable option for pig manure management

In traditional composting, large amounts of bulking agents must be added to reduce the moisture of pig manure, which increases the cost of composting and dilutes the N, P and K content in organic fertilizers. In this study, maggot treatment was used in composting instead of bulking agents. In experiment of selecting an optimal inoculum level for composting, the treatment of 0.5% maggot inoculum resulted in the maximum yield of late instar maggots, 11.6% (maggots weight/manure weight). The manure residue became noticeably granular by day 6 and its moisture content was below 60%, which was suitable for further composting without bulking agents. Moreover, in composting experiment with a natural compost without maggot inoculum and maggot-treated compost at 0.5% inoculum level, there were no significant differences in nutrient content between the two organic fertilizers from the two treatments (paired Student’s t15=1.0032, P=0.3317). Therefore, maggot culturing did not affect the characteristics of the organic fertilizer. The content of TNPK (total nitrogen+total phosphorus+total potassium) in organic fertilizer from maggot treatment was 10.72% (dry weight), which was far more than that of organic fertilizer made by conventional composting with bulking agents (about 8.0%). Dried maggots as feed meet the national standard (GB/T19164-2003) for commercial fish meal in China, which contained 55.32±1.09% protein; 1.34±0.02% methionine; 4.15±0.10% lysine. This study highlights housefly maggot-treated composting can be considered sustainable alternatives for pig manure management to achieve high-quality organic fertilizer and maggots as feed without bulking agents.

Comparative Study of Nirmalya Solid Waste Treatment by Vermicomposting and Artificial Aeration Composting

Temple waste normally contains floral offering, leaves and milk product i.e. “Abishek waste water”, and this solid waste management is one of the important issues in the world, because of shortage ofdumping sites and strict environmental legislation. Now days ‘Nirmalyasolid waste’ is generated in large quantity due toincreased in population are commonly treated using different types of bins by the method of composting or vermicomposting. Vermicomposting of solid waste can be done by using different types of earthworms providing natural and artificial aeration along with mixture of cow dung and soil, artificial aeration is carried out by providing diffused aerators or perforated pipes. The parameters like C/N ratio, temperature, moisture contain are carried out. The main objective of this study is to minimize the problem of solid waste management by treating nirmalya solid waste by vermicomposting and suggesting that which method gives good quality of compost at short interval of time comparing artificial and natural aeration composting.

Isolation of cellulolytic bacteria, including actinomycetes, from coffee exocarps in coffee-producing areas in Vietnam

Microorganisms have been used to decompose cellulolytic waste in agriculture for the past many years. However, much of the cellulosic waste including coffee exocarps which are wastes from raw coffee process in Vietnam is often disposed of by biomass burning and discharged into the environment in developing countries, thus causing considerable environmental pollution. Besides, these organic wastes decompose slowly when they are used to produce compost in ordinary conditions. Therefore, using microorganisms to manufacture natural compost from coffee exocarps is considered a useful and environmentally sound alternative. In the course of screening for cellulose-degrading bacteria and actinomycetes, 38 bacterial strains and 18 actinomycetes strains were isolated from 15 coffee exocarp samples in coffee-producing areas in Vietnam. The isolates grew with cellulose as the sole sources of carbon and energy. The results of cellulolytic activity determinations were that 13 bacteria (>34 %) and 10 actinomycetes (>56 %) showed enzymatic degradation of cellulose. The isolated strains were identified as belonging to members of the Genus Streptomyces, Actinomycetes, Clostridium and Bacillus. Cellulose-degrading ability of the isolated microorganism strains was mostly 96 % with filter paper; however, for coffee exocarps, it was considerably lower, only about 37 % of the cellulose was digested after 30 days of incubation to coffee exocarps. A medium containing rice husk powder and lactose with pH 7.0 positively affected the cellulolytic activity of A1 and A9 strains. Cellulolytic activity of B4 and B7 strains was also most appropriate when the medium contained peptone, CMC, and with a pH 7.0. Optimal temperature for actinomycetes and bacteria isolate strains was at 25–35 °C. We concluded that the cellulolytic bacteria and actinomycete could be isolated from coffee exocarps which are normally discharged into the environment in coffee-producing areas. These microorganisms could be used to decompose cellulosic wastes, making compost from coffee exocarps, which could be applied in agriculture in Vietnam and other developing countries.

Degradability in a natural compost medium of (linear low‐density polyethylene)/(soya powder) blends compatibilized with epoxidized natural rubber

The objective of this study was to investigate the degradability of linear low‐density polyethylene (LLDPE)/(soya powder) blends. The blends were compatibilized by epoxidized natural rubber with 50 mol% of epoxidation. They were exposed to a natural compost medium located in northern Malaysia. The degradability was evaluated by using tensile tests, a morphological study, carbonyl indices, crystallinity measurements, weight loss, and molecular‐weight changes. The tensile strength and elongation at break of the compatibilized blends decreased during one year of exposure. The colonization of fungus and the formation of pores were observed in micrographs. The carbonyl indices, crystallinity, and weight loss increased during exposure, thereby indicating the degradation of the blends. The reduction in molecular weight revealed the degradation of the LLDPE upon composting. Surprisingly, after composting, the compatibilized blends showed more degradation than the uncompatibilized ones. J. VINYL ADDIT. TECHNOL., 20:42–48, 2014. © 2014 Society of Plastics Engineers

Effect of Growing Media and NPK Fertilizer on Growth of Shorea Javanica

Cibodas botanical garden – LIPI had compost product based on organic waste material (litter, grass, twigs, and fruit) which were collected from garden. Compost was produced by two methods : using katalek bioactivator and natural compost without bioactivator. Utilization of compost as growing media at nursery unit botanical garden was not optimal. The objective of this research was to determine the ability of compost from botanical garden as a growing media for seedling collection at Cibodas botanical garden. This study was conducted using a Randomized Block Design (RAB) with six treatments and four replications using Shorea javanica as plants indicator. Three types of growing media (top soil, natural compost and katalek compost) were applied for the treatment with the addition or non addition of NPK fertilizer. However, control treatment was made from top soil without addition of NPK. The data showed that both natural compost and katalek compost were demonstrated better result than top soil growing media. Katalek compost without addition of NPK fertilizer gave significantly different result at enhancement of plant height, leaf number, and dry weight if compared with control.

Effect of Growing Media and NPK Fertilizer on Growth of Shorea Javanica

Title : Effect of Growing Media and NPK Fertilizer on Growth of Shorea Javanica. Cibodas botanical garden – LIPI had compost product based on organic waste material (litter, grass, twigs, and fruit) which were collected from garden. Compost was produced by two methods : using katalek bioactivator and natural compost without bioactivator. Utilization of compost as growing media at nursery unit botanical garden was not optimal. The objective of this research was to determine the ability of compost from botanical garden as a growing media for seedling collection at Cibodas botanical garden. This study was conducted using a Randomized Block Design (RAB) with six treatments and four replications using Shorea javanica as plants indicator. Three types of growing media (top soil, natural compost and katalek compost) were applied for the treatment with the addition or non addition of NPK fertilizer. However, control treatment was made from top soil without addition of NPK. The data showed that both natural compost and katalek compost were demonstrated better result than top soil growing media. Katalek compost without addition of NPK fertilizer gave significantly different result at enhancement of plant height, leaf number, and dry weight if compared with control.

Characteristics of humic-like acid of <I>Aphodius</I>-processed cow manure and natural cow manure compost

分别用焦磷酸钠和氢氧化钠浸提新鲜牛粪、蜉金龟堆肥(APCM)和自然堆肥(腐熟牛粪)产物中的类胡敏酸, 采用元素组成、红外光谱及差热分析研究了其结构特征。元素分析结果表明, 蜉金龟堆肥焦磷酸钠浸提物--类胡敏酸(NaHLA)的芳香性低于新鲜牛粪和自然堆肥, 而碳水化合物及氮元素含量增加。蜉金龟堆肥氢氧化钠浸提物--类胡敏酸(PAHLA)的碳水化合物和氮元素含量也高于新鲜牛粪和自然堆肥, 而自然堆肥PAHLA的芳香性略低于新鲜牛粪和蜉金龟堆肥。红外光谱分析结果表明, 与自然堆肥NaHLA相比, 蜉金龟堆肥NaHLA中羧酸脂类化合物、酮类化合物、脂肪族化合物及碳水化合物有所增加。与新鲜牛粪PAHLA相比, 蜉金龟堆肥和自然堆肥PAHLA的碳水化合物、脂肪族化合物、酚类化合物及纤维素酯类减少, 同时蜉金龟堆肥PAHLA的酰胺化合物在蜉金龟消化过程中被其吸收。差热分析结果表明, 自然堆肥NaHLA的热稳定性高 于新鲜牛粪和蜉金龟堆肥, 而蜉金龟堆肥NaHLA的脂族化合物、外围官能团和分子内部芳香结构含量较高, 分子结构较复杂。蜉金龟堆肥PAHLA存在两个放热峰, 而新鲜牛粪和自然堆肥的中温放热峰消失。综上, 蜉金龟堆肥和自然堆肥采用两种提取液浸提出类胡敏酸的结构特征存在差异性。

Treating Idiopathic Male Infertility with a Combination of Tamoxifen Citrate and a Natural Compost with Antioxidant and Androgen-Mimetic Action

Background: We investigated the efficacy of a combination therapy with tamoxifen citrate and a natural composite containing Tribulus terrestris, alga Ecklonia bicyclis and polymers of d-glucosamine and n-acetyl d-glucosamine in treating male idiopathic infertility. Methods: In this prospective, randomized double blind, placebo-controlled study, we enrolled ninety infertile men at our department of urology at University Federico II of Naples. Mean age was 29.2 ± 7.8 [± SD]. Inclusion criteria consisted of the repeated exhibition of oligoasthenozoospermia (OA) without detectable cause (unexplained OA). Patients were randomly assigned to three treatment groups: Group A (n=30) receiving tamoxifene citrate (20 mg/day) and a natural composite with an antioxidant and androgen-mimetic action (150 mg of alga Ecklonia Bicyclis, 396 mg of Tribulus terrestris and 144 mg of polymers of d-glucosamine and n-acetyl d-glucosamine); Group B (n=30) receiving tamoxifene citrate (20 mg/day) and Group C receiving placebo (n=30). We evaluated the number of spontaneous pregnancies, sperm volume, concentration, sperm total motility, sperm forward progressive motility, normal sperm morphology. Results: After 6 months of therapy the number of spontaneous pregnancies was markedly higher in the Group A (13 pregnancies, 33.3%) then the other two groups: Group B (6 pregnancies, 20%) and Group C (4 pregnancies, 13.3%). Sperm concentration improved in the Group A from a mean 8.49 × 106 cells/ml ± 5.57 at baseline to 22.1 × 106 cells/ml ± 1,63 (p ≤ 0.001). In the Group B there was an improvement from a mean 7.98 × 106 at baseline to 14.43 × 106 cells/ml ± 3,43 (p=0.002). Group C did not see a statistically significant improvement of sperm number, from a concentration of 9.65 × 106 cells/ml ± 6.54 to 10.53 × 106 cells/ml ± 8.5 (p=0.0025). In Group A, sperm total motility improved from 31% ± 11% at baseline to 40% ± 14% (p=0.007) whilst the forward progressive motility slightly improved from 5% ± 3% to 9% ± 4% (p=0.0034). In the group B and C, there were not reported statistically significant changes of motility. Conclusions: The combination therapy with tamoxifen citrate and the natural compound with an andorgen-mimetic and antioxidant action leads to a higher incidence of pregnancy rates and gives a statistically significant improvement of semen parameters comparing with the single use of tamoxifen citrate and with the control group.

Effect of Microbiological Additive on the Diversity of Microbial Community and the Dynamic Distribution during High-Temperature Composting Process

The objectives of this study were to analysis the differences of microbial community diversity between the microbial additives (MA) compost and natural compost and the distribution (spatial and temporal) of MA during high-temperature composting by PCR-DGGE technology. The results showed that the MA started temperature rapidly; prolonged the time of maintained high-temperature process and increased the diversity of microbial than natural compost. Sequence comparison revealed that the microorganisms most belonged to uncultivable, thermophilic bacteria. Bacillus became the dominant microorganisms after mixed with MA. MA were found in the top and middle portions of the compost throughout nearly the entire composting process,but absent in the natural compost. Our finding represents an important step towards the understanding of MA and its function in the degradation process of compost.

Selection of biological control agents against tomato Fusarium wilt and evaluation in greenhouse conditions of two selected agents in three growing media

Two biological control practices are the use of suppressive growing media and the application of biological control agents (BCAs). The goals of this study were: (i) to screen 584 potential BCAs obtained from Fusarium wilt (FW) suppressive growing media; (ii) to evaluate in greenhouse conditions selected BCAs in three growing media with different degrees of suppressiveness of tomato FW. Two isolates selected after screening were identified as Fusarium solani (305) and Streptomyces sp. (A19). Results showed that tomato FW was reduced and total production was improved when both BCAs were applied to a conducive medium (coir fiber). In highly suppressive growing medium (grape marc compost), A19 and 305 inoculations did not improve suppressiveness. In moderately suppressive growing medium (cork compost), only A19 improved this compost to natural grape marc compost suppressiveness level. Therefore, compost suppressiveness of tomato FW depended on the nature of the compost and on the isolates applied.

Thermal, mechanical and morphological characterization of plasticized PLA–PHB blends

A blend of poly(lactic acid) (PLA) (75% by weight) and poly(3-hydroxybutyrate) (PHB) (25% by weight) with a polyester plasticizer (Lapol 108) at two different concentrations (5 and 7% by weight per 100 parts of the blends) were investigated by TGA, DSC, XRD, SEM, mechanical testing and biodegradation studies. PLA/PHB blends showed a good distribution of the major components and absence of phase separation. XRD showed that the original crystal structure of PHB in the PLA75/PHB25 blend had been disturbed. DSC curves of PLA or PHB with plasticizer exhibited one Tg value, indicating that both major blend components are miscible. The Tg values also decreased with increased amount of plasticizer and showed good correlation to the Fox Equation, The melting temperature of PLA and PHB blends mostly did not change with an increase in plasticizer content, and the thermal stability of PLA and PHB was not affected. Also, the elongation at break of the PLA/PHB blend was greatly improved with the addition of plasticizer. In addition, in preliminary biodegradation studies carried in natural compost neat PHB showed some biodegradation, whereas the samples containing PLA did not experience a substantial biodegradation. This last aspect is worthy of further investigation in a more comprehensive and detailed approach.

Biodegradability studies of poly(butylene succinate)/organo-montmorillonite nanocomposites under controlled compost soil conditions: Effects of clay loading and compatibiliser

Biodegradable nanocomposites were prepared from poly(butylene succinate) (PBS) and organo-montmorillonite (OMMT), in the presence of maleic anhydride-grafted PBS (PBS-g-MA) as compatibiliser. The effects of OMMT loading and PBS-g-MA on the biodegradability of PBS nanocomposites were investigated. Soil burial testing was carried out for 180 days in natural organic humus compost soil under controlled conditions. It is noted that the weight loss of nanocomposites was lower than that of neat PBS, due to the enhanced barrier properties after addition of OMMT. However, the addition of PBS-g-MA increased the weight loss of nanocomposite. The mechanical properties of PBS nanocomposites were significantly reduced after the soil burial. Biodegradation of the material was further confirmed by the decreased molecular weight through gel permeation chromatography (GPC), and changes in the chemical structure as verified by Fourier transform infrared (FTIR) spectroscopy. This was supported by the degraded surface of PBS and the nanocomposites observed under scanning electron microscopy (SEM). The effects of biodegradation on the thermal properties were studied through the differential scanning calorimetry (DSC). In addition, the biodegradation rate of the materials was determined by measuring the carbon dioxide (CO2) evolution. The degraded samples were recovered and PBS-degrading bacteria were found to be present in the exposed samples.

Rapid production of maggots as feed supplement and organic fertilizer by the two-stage composting of pig manure

A two-stage composting experiment was performed to utilize pig manure for producing maggots as feed supplement and organic fertilizer. Seven-day composting of 1.8ton fresh manure inoculated with 9kg mixture of housefly neonates and wheat bran produced 193kg aging maggots, followed by 12week composting to maturity. Reaching the thermophilic phase and final maturity faster was characteristic of the maggot-treated compost compared with the same-size natural compost. Upon the transit of the maggot-treated compost to the second stage, the composting temperature maintained around 55°C for 9days and the moisture decreased to ∼40%. Moreover, higher pH, faster detoxification and different activity patterns for some microbial enzymes were observed. There was a strong material loss (35% water-soluble carbon and 16% total nitrogen) caused by the maggot culture in the first stage. Our results highlight a higher economic value of pig manure achieved through the two-stage composting without bulking agents.

Generation of a cDNA library reveals the presence of a Ty-1/copia transposon in Phellinus rimosus (Hymenochaetaceae, Basidiomycota)

Lignocellulolytic fungi have significant potential as bio-convertors with a particular capacity to degrade recalcitrant natural composts, such as lignin. We generated a cDNA library of a lignocellulolytic fungus, the Phellinus rimosus (Hymenochaetaceae, Basidiomycota), and a typical species of polypore mushroom from the Brazilian semi-arid region. To the best of our knowledge, this is the first report ever to describe the existence of a Ty1-copia retrotransposon in the P. rimosus species. Given the taxonomic complexity in the Brazilian semi-arid region, our findings will be useful as they provide a molecular identity to this important parasite species of the semi-arid region of Brazil. Key words: Lignocellulolytic fungi, biotechnology, Phellinus rimosus, Ty-1 copia, Brazilian semi-arid region, molecular marker.

Influence of Nitrogen Containing Wastes Addition on Natural Aerobic Composting of Rice Straw

Problem statement: Rice straw is an agricultural residue. Typically, the rice straw can be burn in the rice field after the harvesting process . The burning can cause air pollution. Another alternative rice straw management method is animal feed. The amount of rice straw is enormus in Thailand. Another sustainable way to manage rice st raw is required. Rice straw is used as main waste to compost with nitrogen containing wastes such as golden apple snail, cattle dung and urea in natural aerobic composting reactors. The golden apple snail is a pesticide and cattle dung is an animal waste. Both materials are all waste of low values. The mai n purpose of this study was to determine the influence of nitrogen containing wastes addition to rice straw on the performance of natural aerobic composting process in terms of the following parameters: pH, temperature, organic matter, C/N ratio, electrical conductivity and GI. The impact of this study is to reuse agriculture residue by composting . Approach: The experiments was consisted of three reactors. T he reactor 1 contains the rice straws and golden apple snails while the reactor 2 contain s the rice straws, golden apple snails and urea. Th e reactor 3 contains the rice straws, cattle dung and urea. The experiments were carried out in designed natural aerobic reactors (60 L) under cont rolled laboratory conditions over 60 days. The analysis was done every 5 days however the temperature was measured daily. Results: The experimental results showed that the initial C/N ra tio was 30.7, 30.3 and 31.8 in the reactor 1, 2 and 3, respectively. After the 60-day period, the final C/N ratio was reduced to 17.9, 16.9 and 18.4 in the reactor 1, 2 and 3, respectively. The main nutr ients (N: P: K) from all reactors achieved the standard level for Thai compost standard. The rice straw as agricultural residue was suitable for co- composting with golden apple snails and cattle dung as the nitrogen containing wastes. Conclusion: The final compost is the good quality compost accor ding to the Thai compost standard. The moisture content is slightly higher than the Thai c ompost standard. The final compost can be dry in the air to reduce moisture before use. The final co mpost can be use as a fertilizer.

Effect of microbiological inocula on chemical and physical properties and microbial community of cow manure compost

Abstract The effect of the microbiological inocula to efficiently decompose animal manures into mature compost was studied. In general, TOC, water contents and C/N ratio decreased during decomposition in two composts and those properties dropped faster in the microbiological inocula compost than the natural compost. The total nitrogen content and NO 3 − –N behaved in the opposite manner and those properties increased faster in the microbiological inocula compost than the natural compost. The pH and NH 4 + –N increased first, and then decreased in two composts. The microbiological inocula showed a more rapid rate of temperature elevation at the start of composting and prolonged the time of high-temperature process. The microbiological inocula were able to facilitate the microbial diversity of the compost. Based on germination assays, the microbiological inocula seems to be advantageous in reducing the maturation time of cow manure compost.

Influence of organic matter and solute concentration on nitrate sorption in batch and diffusion-cell experiments

Nitrate sorption potentials of three surface soils (soils-1–3) were evaluated under different solute concentrations, i.e. 1–100 mg L −1. Batch and diffusion-cell adsorption experiments were conducted to delineate the diffusion property and maximum specific nitrate adsorption capacity (MSNAC) of the soils. Ho’s pseudo-second order model well fitted the batch adsorption kinetics data ( R 2 > 0.99). Subsequently, the MSNAC was estimated using Langmuir and Freundlich isotherms; however, the best-fit was obtained with Langmuir isotherm. Interestingly, the batch adsorption experiments over-estimated the MSNAC of the soils compared with the diffusion-cell tests. On the other hand, a proportionate increase in the MSNAC was observed with the increase in soil organic matter content (OM) under the batch and diffusion-cell tests. Therefore, increasing the soil OM by the application of natural compost could stop nitrate leaching from agricultural fields and also increase the fertility of soil.

Research on Nitrogen and Phosphorus Losses of Natural Composting Manure in the Northern Region of Erhai Lake

In recent years, the trend of eutrophication appeared in Erhai and the phenomena of small-scale algae outbreak has already happened. Erhai Lake pollution caused by many reasons.As an important factor of Erhai lake eutrophication, superabundant manure stacking at random in rural areas of Erhai Lake Basin and transference of the manure nitrogen and phosphorus into waterbody have attracted much attention of environmental researchers eutrophication of Erhai lake. The nitrogen and phosphorus contentes of livestock manure in the process of naturally composting were mensurated and the transference characteristics of the manure nitrogen and phosphorus were analysed. As a result, the regular pattern and loss type of livestock manure were advanced and advices about developing solid waste treatment facilities were brought forword.

Biotechnology for in vitro growing of edible and medicinal mushrooms on wood wastes

The aim of this work was focused on finding out the best way to convert the wood wastes into useful food supplements, such as mushroom fruit bodies, by using them as growing sources for the edible and medicinal mushrooms. According to this purpose, three fungal species from Basidiomycetes, namely Ganoderma lucidum (Curt.:Fr.) P. Karst, Lentinus edodes (Berkeley) Pegler and Pleurotus ostreatus (Jacquin ex Fries) Kummer were tested to determine their biological potential to grow on substrates made of wood wastes (sawdusts as well as shavings) which could be used in this way as main ingredients for preparation of natural culture composts. The experiments were achieved by in vitro growing of all these fungal species in special rooms, where the main culture parameters were kept at optimal levels in order to get the highest production of mushroom fruit bodies. The effects of culture compost composition (carbon, nitrogen and mineral sources) as well as other physical and chemical factors (such as: temperature, inoculum amount, pH level and incubation time, etc.) on mycelial net formation and especially on fruit body induction, were investigated. From all these fungal species tested in our experiments, P. ostreatus was registered as the fastest mushroom culture, then L. edodes and finally, G. lucidum as the longest mushroom culture. During the experiments, different logs of the same species were used as control samples for each culture compost variants. Applying such biotechnology, the environmental problems generated by the plant wastes accumulation in wood industry could be solved only by using biological means for their valorising, simultaneously with food supplements producing having high nutritive values as well as healing effects by increasing the consumers` health.

Use of 15N-depleted artificial compost in bound residue studies

Association of bound residues to soil humic matter may be accomplished by different binding mechanisms such as sequestration in hydrophobic interiors of the organic material or covalent linkage to the organic matter. The structures and chemical environments of compounds can be observed by NMR spectroscopy. We applied 15N-NMR spectroscopy to study the soil-bound residues of 15N-labeled simazine. As the 15N-isotope has a low sensitivity and natural abundance 15N-NMR experiments require long measurement times and often result in low signal-to-noise (S/N) ratios. Therefore, in addition to the use of 15N-labeled simazine, 15N-depleted compost was used to reduce the amount of background signal and enhance the sensitivity. The compost was produced from maize and wheat plants grown on sand with 15N-depleted NH 4NO 3 as sole nitrogen source. The plants were freeze-dried, ground and mixed with sand for composting. After a composting period of 224 days analysis of the compost revealed a 15N-content of 267 ppm as opposed to a natural abundance of 3650 ppm. Characterization of this artificial compost produced parameter values similar to those of a natural compost. The 13C-NMR-spectra of the humic and fulvic acids during different stages of maturity showed that there was a shift from single-bond functional groups to more complex double-bond and aromatic structures. Experiments with this compost showed an increased signal intensity. The improved sensitivity made it possible to obtain interpretable NMR signals in contrast to experiments with 15N-simazine on native soil where no signals were detectable. The data indicated that the bound residues of simazine are composed of metabolites resulting from N-dealkylation and triazine ring destruction. Silylation of the bound residues showed a very strong binding of the residues to the matrix as only a small fraction could be solubilized.