In this study species richness of earthworms in the Central Elburz Mountains is reported for the first time based on samples collected from 33 localities along the Haraz and Chalus rivers. Twelve species were identified representing seven genera from family Lumbricidae (Rafinesque-Schmaltz 1815): Aporrectodea caliginosa (Savigny 1826), A. rosea (Savigny 1826), A. jassyensis (Michaelsen 1891), Dendrobaena byblica complex (Rosa 1893), D. octaedra (Savigny 1826), D. hortensis (Michaelsen 1890), D. veneta (Rosa 1886), Dendrodrilus rubidus (Savigny 1826), Eisenia fetida (Savigny 1826), Eiseniella tetraedra (Savigny 1826), Octolasion lacteum (Orley 1881), Perelia kaznakovi (Michaelsen 1910). All the reported species were common, with Eiseniella tetraedra being dominant in both areas.

BACKGROUND AND OBJECTIVE: Increasing of world population and excessively consumption of the needed materials result to greatly household solid wastes generation that can threaten human health and environment. Thus, application of appropriate methods for solid waste disposal is effective on community health. This study was performed to identify the capability of native earthworms of Mazandaran province (Iran) for compost production from household solid wastes.METHODS: In this cross sectional study, the types of earthworms were separated based on appearance characteristics. Plastic bin, loam soil, sand and animal fertilizer were used for bedding. 50 gr of vegetable (lettuce) was poured on the bed. Earthworms with a certain number and weight were located on soil bed. Sequential water was added to beds for moisture control. Seventeen and thirty-five days after loading, the soil of different beds were assessed for chemical and microbiological analysis.FINDINGS: The organic matter, organic carbon, nitrogen, phosphorous and electrical conductivity in initial substrate and vermicompost increased from 16.8% to 40.2 and 45.2%, from 1.95% to 3.9 and 5.85%, from 1.1% to 3.6 and 3.9%, from 1.8% to 2 and 2.6% and from 344 to 372 and 1068 microsiemens per centimeter, respectively. Ash percentage, C/N ratio and total coliforms in initial substrate and vermicompost decreased from 83.2% to 65% and 59.8%, from 1.75% to 1.63% and 1.49 %and from 4.5×106 to 3.3×103 and 1.3×103 MPN/100ml, respectively.CONCLUSION: The results of this study showed that earthworms can produce compost from household solid wastes during 17 days.

Production of vermicompost from sewage sludge is one of the suitable methods for convert of this waste to organic fertilizer. In this study, effects of decomposition stage of sludge and bulking materials on growth of earthworms were investigated. Experimental design was split factorial in three replications. The main factor was the stage of sewage decomposition (raw sewage, digested sludge in digester, dewatered sludge in lagoons, and final dried sludge in lagoons), and kind of bulking materials (woodchips, tree leaves, and wheat straw) and mixing proportion of bulking materials to swage sludge (0, 15, 30, and 45 %, V/V) were as subordinate factors. After 5 months incubation of pots in controlled moisture and temperature conditions, numbers of worms, cocoons, wet body weight of worms, and concentration of nutrients and heavy metals in produced vermicompost were measured. Population of worms, their body weight and cocoon production were highest in the pots contain final dry sludge. The  growth and reproduction of earthworms were greater when wood chips used as bulking material for vermicompost production. There was no significant difference between wheat straw and tree leaves in this respect. The suitable mixing proportion of bulking material and sewage sludge was 30 % (V/V). Therefore, mixing of wood chips with dry sewage with the proportion of 30 % (V/V) for vermicompost production and use of this technique to improve the stability of sewage sludge produced in sewage treatment plants are recommended.

Soil microbial fuel cells (SMFCs) could generate electricity from the organic matters in the soil. We focused on the soil ecosystems, specifically the earthworms which were known to improve the soilfertility. The aim of this study was to investigate the effect of earthworm on power generation of the SMFC. The maximum power density and the internal resistance were compared to the SMFC with and without earthworms. The power density increased 9 times and the internal resistance decreased by 8. 5 times. The soil structure of the SMFC with and without earthworms was different and the clear soil aggregate structure was found in the SMFC with earthworms, which had been made with the passage of soil through the earthworm gut. The results indicated that adding earthworms had a significant effect on the SMFC performance, especially the power, internal resistance and soil structure. It was considered that the soil environments were changed biologically and physicochemically by adding earthworms into SMFC and these changes had a positive influence on the SMFC.