Development of a Self-Sustaining Wastewater Treatment with Phosphorus Recovery for Small Rural Settlements

Global trends such as climate change and the scarcity of sustainable raw materials require adaptive, more flexible and resource-saving wastewater infrastructures for rural areas. Since 2018, in the community Reinighof, an isolated site in the countryside of Rhineland Palatinate (Germany), an autarkic, decentralized wastewater treatment and phosphorus recovery concept has been developed, implemented and tested. While feces are composted, an easy-to-operate system for producing struvite as a mineral fertilizer was developed and installed to recover phosphorus from urine. The nitrogen-containing supernatant of this process stage is treated in a special soil filter and afterwards discharged to a constructed wetland for grey water treatment, followed by an evaporation pond. To recover more than 90% of the phosphorus contained in the urine, the influence of the magnesium source, the dosing strategy, the molar ratio of Mg:P and the reaction and sedimentation time were investigated. The results show that, with a long reaction time of 1.5 h and a molar ratio of Mg:P above 1.3, constraints concerning magnesium source can be overcome and a stable process can be achieved even under varying boundary conditions. Within the special soil filter, the high ammonium nitrogen concentrations of over 3000 mg/L in the supernatant of the struvite reactor were considerably reduced. In the effluent of the following constructed wetland for grey water treatment, the ammonium-nitrogen concentrations were below 1 mg/L. This resource efficient decentralized wastewater treatment is self-sufficient, produces valuable fertilizer and does not need a centralized wastewater system as back up. It has high potential to be transferred to other rural communities.

Experimental Study on Cracking Behavior and Mechanism in Desiccating Soils in Xi’an, Shaanxi Province, China

Drying-induced cracks are frequently observed in soils, which can severely influence the mechanical parameters of soils in geotechnical engineering applications. In addition, geohazards can also be accelerated with the formation of preferential path in slopes caused by cracks in soils. This study aims to analyze the cracking behaviors and mechanisms of a special soil collected in northwestern China using experimental methods. Local displacements and strains can be obtained and analyzed with Digital Image Correlation (DIC) method. Combined with DIC method, the tensors maps with total “mechanical” principal strain are drawn. Cracks in mixed opening-sliding mode are identified and the curling phenomenon of soils is observed in situ. Three typical types of crack patterns are observed, which are “T,” “Y,” and “wave-ring,” respectively. Crack pattern of “T” is more frequent than the other two types. The identification of cracking behaviors and mechanisms is helpful for the analysis of mechanical properties of soils and the prevention of geohazards in northwestern China.

Weed Control in Chickpea Crops in Lower Volga

Chickpea is a cheap source of nutrients and does not require special soil conditions of growth. In addition, the properties of the symbiotic relationship of nitrogen-containing bacteria in its root system make it a valuable crop for agriculture. Due to its droughtresistant properties, it is one of the most dynamically developing cultures in export potential, which allows producers making profitable trading operations in foreign food markets and improving their financial condition. The climatic conditions of the Russian Federation make it possible to grow chickpeas and produce its seeds. The cultivated areas of chickpea in Russia in 2018, according to Russian Statistic Agency, amounted to 851.2 thousand hectares. Over the year, they increased by 71.6 %, from 2013 – by 26.5 %. Volgograd region in the all-Russian chickpea field occupies 22.5 % after the Saratov region, on yield it occupies the seventh position after the Stavropol Territory – 7.7 c/ha. Chickpea is a valuable crop, the cultivation of which will make it possible to obtain grain beans that are valuable for human food and to engage Russian agricultural producers in export operations. However, weed vegetation reduces the efficiency of chickpea production. The article describes a method of dealing with weed vegetation in chickpea crops in dry conditions. This will allow the use of tank mixtures of herbicides, which are cheaper in cost and effective in combating weeds in chickpea crops. Using this method, it is possible to get a crop without spending extra funds and achieve a profitability of 15 and 25.6 %.

ISOLASI DAN PENENTUAN INDEKSHIDROLISIS BAKTERI AMILOLITIK DARI TANAH SEDIMENT MANGROVE DI WONOREJO, SURABAYA

Mangrove sediment is a habitat for various bacteria, one of them is amylolytic bacteria which has the potential to produce amylase enzyme. Amylase enzyme has many benefits in industry, textiles and medical. The mangrove ecosystem area has special soil characteristics, which have the opportunity to have microorganism diversity, one of which is the mangrove ecosystem in the Wonorejo region, Surabaya. This study aims to obtain potential amylolytic bacteria from potential amylolytic isolates derived from mangrove sediment. Soil bacteria were isolated in Starch media for 2% agar and tested with Lugol’s Iodine reagents to measure their amylolytic index. Character isolates observed included colony morphology, Gram staining, and motility. Of the 27 isolates found there were 3 isolates with the highest index values in their activity, namely isolates A.7, A.27 and A.64. Characterization results showed that isolates A.7 and A.64 were Gram negative bacteria, and isolates A.27 were Gram positive bacteria. And the motility results for the three isolates were negative, with the results of a positive catalase test.

F. Yu. Levinson-Lessing (1861-1939) -V. V. Dokuchaev apprentice and follower and his role in Soil Science Institute foundation

The world-class geologist and petrographer - Frants Yul’evich Levinson-Lessing (1861-1939) was one of the followers and apprentices of V.V. Dokuchaev, the founder of the Soil Science. In 1882-1892 he took part in Dokuchaev’s expeditions. Thereafter, Levinson -Lessing carried out research in the field of petrography; he assumed various administrative positions and constantly lent support to his teacher’s life-work. He was the chairman of the Soil Commission of the Russian Free Economic Society (1905-1912), one of the founders of Dokuchaev Soil Committee and its council member (1912-1916), headed Soil Science Department and Soil Science Institute of the Commission on Natural Production Forces affiliated with Academy of Sciences of the USSR (1917-1925), V.V. Dokuchaev Soil Science Institute (1926-1929). In 1927 in cooperation with V.I. Vernadskiy and K.D. Glinka he gained recognition of the Soil Science as a fundamental science in Academy of Sciences of the USSR, which resulted in establishment of special Soil Science Institute of Academy of Sciences of the USSR.

Statistical Analysis of Influence of Cover Depth on Loess Tunnel Deformation in NW China

Loess is a kind of special soil with structure and hydrocollapse behavior; due to the particularity of loess, the deformation regularity of the tunnel in loess shows different characteristics from those in rock. To ensure the safety of construction, crown settlement (CS) and horizontal convergence (HC) are widely used to assess the stability of the tunnel structural system. Based on statistical analysis, this study focused on analyzing the influence of cover depth on the deformation of surrounding rock of loess tunnels by ANOVA, and relationships between them were presented by regression analysis. The achieved results indicated that the influence of cover depth on deformation was not obvious in shallow tunnels, while the cover depth had a significant effect on deformation in deep tunnels. Based on the difference of influence of cover depth on deformation between shallow tunnels and deep tunnels, a method for determining the cover depth threshold (CDT) in the tunnel by statistical analysis was proposed. The horizontal and vertical deformations in shallow tunnels were discrete and obeyed the positive distribution, mainly concentrated within 200 mm. The deformation allowance in shallow tunnels was recommended to be 200 mm. In deep tunnels, as the cover depth increased, the deformation increased linearly, while the CS/HC decreased.

Biological and topochemical studies on the resistance of excavated oak piles (Quercus sp.) from a historical bridge in Bavaria

Archaeological wood of 13 excavated oak piles from five historical bridge generations in Bavaria, dated from 1447 to 1787, was investigated by means of light microscopy (LM) and cellular UV-microspectrophotometry (UMSP) to study the ageing and natural resistance of the excavated wood. Furthermore, the mineral content of the ancient wood was determined to evaluate the impact of mineral inclusions on microbial resistance, tested using a mini block fungal test. The LM and UMSP analyses revealed well preserved cell wall structures and no significant modification of the lignin composition and distribution in predominant parts of the piles. Slight microbial decay caused by soft rot and erosion bacteria was only detectable at the outermost millimetres of individual piles. The fungal mini block tests yielded mass losses of ancient oak samples between 15% and 30%, independent of their analysed mineral content. The results provided evidence that the fungal resistance of the investigated ancient wood is mainly determined from the special soil with its high mineral content.