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One of the most pressing environmental problems worldwide is sewage sludge (SS) management. Every year, wastewater volume increases and thus, the amount of SS produced increases as well. The disposal of SS in landfills, as practiced in many countries, is not a sustainable solution. Instead, SS, rich in organic matter and other nutrients, can be used as an alternative soil additive or fertilizer. The properties of these materials depend on their chemical composition and the method of treatment. Experience from a number of countries, such as the US and Europe, has shown that SS can be transformed from a waste into a valuable resource, provided that the final product fulfils the relevant regulatory standards. This review examines the sustainable conversion of SS to sustainable fertilizers, the impact on waste minimization, and the potential benefits in agriculture.

IntroductionTrophic ulcers are a common health problem, and there are numerous treatment methods. Irreversible damage in the skin, subcutaneous tissue, and fascia with long-term ulcer existence make standard autotransplantation inneffective. Skin grafts are often complicated by partial or complete rejection of skin flaps. The aim of this study was to examine the feasibility of using transplanted cultivated allogenic fibroblasts on the backing of a cellularless xenogenic fabric for wound healing.MethodsTransplantation of cultured embryonic fibroblasts on a backing of xenogenic tissue was used in the complex treatment of trophic ulcers for stimulation of regenerative processes. Decellularization xenogenic film was previously held. Then allogenic fibroblasts were cultivated on the surface of collagen-elastin matrix. Since 2013, we treated 12 patients with giant ulcers caused by the following: lymphedema (2 patients), vascular disease (3 patients), diabetes (2 patients), after injury (4 patients), and radiation ulcer (1 patient). Dimensions of ulcers were from 150 to 600 cm2. Duration of the lower limb ulcers ranged from 8 months to 10 years. For a number of years, all patients were on a complex therapy, which had not resulted in healing wounds. During the operation when excision of granulation tissue was performed, plastic wounds perforated with the ratio 1:2 autoskin. Xenogenic fabric with cultured fibroblasts was applied on top. In this case, xenogenic film protected the skin from drying, created optimal microclimate, and cultured fibroblasts stimulating regeneration and improving engraftment.ResultsThe first redress was held on the fifth day. In all cases, the results of engraftment skin grafts achieved maximum possible (100%) and optimal (90%). Complete epithelialization of the cell perforation was seen in five patients on the fifth day and three on seventh day after skin plastics. Average period of inpatient treatment was 20.7 days. All patients were discharged with healed wounds.ConclusionThus, the treatment of trophic ulcers can be successfully solved using advances in biotechnology. Transplantation of cultivated allogenic fibroblasts on a backing of cellularless xenogenic fabric shows good clinical results due to the stimulation of regenerative processes and creates the optimum environment for autotransplants.

IntroductionBurns are an important public health challenge due to the frequency of getting burns in day-to-day life, occupational hazards, and catastrophes. Treatment of burns is complex and is associated with high morbidity and mortality. Duration and complexity of burn treatment require finding new ways of curing and rehabilitating burns. The result of burn treatment plays a significant role in post-traumatic status of a patient and his or her consequent adaptation in society. Chitosan is a natural safe non-toxic product compatible with human tissues, characterized by hydrosorbid, anticoagulant, antibacterial, and wound healing features. The study aims to show a clinical application of chitosan-pectin scaffold with cultured human skin fibroblasts in the treatment of deep burns.MethodsThe substrate was prepared by dissolving 3% chitosan in 0.5N acetic acid, which was then mixed with 3% solution of pectin dissolved in distillated water. Chitosan film was formed in a Petri dish for 20–24 hours at 20–25 °C. After drying the film, cultured allogeneic fibroblasts (patent number RK-25091) were seeded on its surface.ResultsThe results from an in vitro culture study showed that human allogeneic fibroblasts could adhere well and grow on the selected scaffold with a typical morphology. During autodermoplasty surgery, cultured allogeneic fibroblasts were applied on granulating wounds of 9 patients with IIIA to IVB degree burns and limited donor resources. Wounds treated with the fibroblastseeded scaffold among all patients provided the highest level of re-epithelialization (day 5), in comparison to cell-free scaffold (day 7) and untreated surface of wounds (day 10).ConclusionOur results indicate the potential use of chitosan for wound healing due to its allogenic fibroblast adherence to scaffolding as well as high epithelization. This warrants further studies on chitosan for use in wounds resulting from third and fourth degree burns.

Agrogels, a hydrogel applied in the soil that collects water during irrigation or rainfall and distributes moisture to plant roots during drought, are a solution to water shortage concerns. Extending the release of low molecular weight chemicals has the potential to minimise mineral fertiliser losses as well as water and soil pollution. Thus, the aim of the research is to obtain chitosan from insect chitin, to synthesize a hydrogel based on chitosan with included mineral and organic fertilisers, and to report on experiments with agrogels in the field. In this study, chitosan was obtained from the adult beetles Zophobas morio. IR spectroscopy was used to examine chitosan. The existence of absorption lines typical of primary amines was demonstrated. In one step, a technique for the manufacture of chitosan-based hydrogels containing embedded mineral fertilisers was established. Hydrogel has a swelling coefficient of 60 g/g. Agrogels were evaluated while planting spruce seedlings on “Semei Ormany” LLP experimental locations. The survival rate of seedlings was found to be 40% higher in the experimental group than in the control group.